Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: MANDO on March 31, 2005, 07:06:21 AM
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The comparison chart posted by Crumpp here:
http://www.hitechcreations.com/forums/showthread.php?s=&threadid=129772&goto=lastpost (http://www.hitechcreations.com/forums/showthread.php?s=&threadid=129772&goto=lastpost)
shows D9 at 2.03 ata doing 386 mph at sea level. When was the D9 cleared for 2.03 ata? The chart "seems" to be signed 3 Jan 1945.
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According to all sources i have seen so far never.
2.03ata boost pressure is available only in JUMO213 engines that are 1900PS basis, as noted on the chart.
The 2.03ata is most likely the 2240PS curve shown in a JUMO213A chart that has 1900PS as Start/Notleistung, which indicates it's a power chart of the 1900PS basis.
From handbook notes, TAM reports mentioned in various books, the highest power level cleared for operational use on the JUMO213A was 2100PS@3250rpm@1,8ata.
The following topic in the LEMB might be interesting to read:
http://p069.ezboard.com/fluftwaffeexperten71774frm9.showMessage?topicID=357.topic
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What about the 190D-11? It had a higher boosted engine than the D-9 IIRC:
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While ata is not printed, look at curve 5 showing near 640 kmh (397mph) at sea level, I would say it corresponds with 2.03 ata and it comes from a real D9 (ETC 504 included).
Fw 190 D-9 Speed (http://www.terra.es/personal2/matias.s/d9speed2chart.jpg)
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While ata is not printed, look at curve 5 showing near 640 kmh (397mph) at sea level
:eek: :eek: :eek:
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Ever since first seeing that data I've thought that that would be my dream piston engined perk plane! :)
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Mando, this data is calculated, it comes from a summary about FW190D performance.
I have gone very deep into researching the performance of the D9 as you might know and so i can tell with 99% certainty that there excists no flight test of any D-Series FW190 using either Erhöhte Notleistung or MW50.
Speed graph that contain curves for those powersettings are calculated.
Know tests of D9 at Langenhagen and Rechlin where done at a max power setting of ~1750PS@3250rpm@1,5ata.
And if you read the thread in the LEMB you will notice that so far no engine power curve was found that corresponds to the 397mph graph.
Power of this setting is somewhere around 2400PS. Ask Henning he can calculated the power for you.
After years of research into the D9 and many talks to Bryan Bury, Willaume, Crumpp and also Butch2K, i must admit that for the D-Series of the FW190 we face a scarce source situation. In late '44 and early '45 the german research resources were extremely limited. Most systems were no longer evaluated like in 41, 42 or even 43.
Best example is the MW50 system, sadly the FW190D that was supposed to flight test the system was destroyed on a landing before testing began. After that the MW50 system seems to have only been gone through ground testing in the V58 if i remember correctly (you can look in up in D. Hermanns FW190 Long Nose).
Neither Bryan nor Willaume could tell me if an allied performance flight test of the FW190D survived up to today. We know they should be there, cause both the RAE and the US AF had some D-Series planes to test flight. But noone could yet dig out those reports, they seem to have vanished.
For the FW190A it's a different picture, because the BMW801F tests were done in '43 and so there are some evaluation showing the performance gain due to boost pressure increase.
@GScholz: Look again at the graph and you will see that the curve for the D9 with 2.03ata has the shape that fits to the supercharger of the JUMO213A. A D11 would have either a JUMO213F or EB which are both high alt engines and would provide a performance very similar to the D12/13 curve in the table.
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Naudet, which chart is calculated? The one from Jan 45 posted by Crumpp or the one posted by my dated march 45 (hardly readable)? Or both? Note that the top speeds at sea level are quite different, 386 mph the first and 397mph the second.
Which are the last dates of the TAM reports you mention?
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Both are calculated.
Think Dez '44 or Jan'45 for the TAM reports. Do you own D. Hermanns Book? If not, buy it, it's a must read. From my viewpoint it's the new reference if it comes to FW190D developement and performance history and he presents many original documents.
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Problem may be the info from jan 45 to the end of the war.
If these TAM reports are older than Jan 45 then they do not give us an accurate idea about possible higher ata clearance along the last months.
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If these TAM reports are older than Jan 45 then they do not give us an accurate idea about possible higher ata clearance along the last months.
As so far none brought up later reports and those reports mentioned never give a hind to a power level above 2100PS, the most simple and most logical solution is that there never was one until the end of the war.
Any discussion of the operational use and possible performance would be highly speculative, not supported by any source i know.
I happen to visit the Archive of the german museum in munich in march to find some interesting documents about the FW190D and JUMO213A.
I am especially interested in handbooks and flight reports, if i run accross a note, passage or whatsoever indicating that D9s ever flew at a higher power level than 2100PS i will be the happiest man alive, but i don't think it will be there.
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Mando,
Naudet knows what he is talking about when it comes to the Dora.
Ignore that chart for anything except the FW-190A's.
Some Dora Charts which you might find useful:
Jumo 213A Power:
(http://www.onpoi.net/ah/pics/users/503_1112615377_jumo213a1.jpg)
Dora Performance:
(http://www.onpoi.net/ah/pics/users/503_1110499629_d9speed.gif)
(http://www.onpoi.net/ah/pics/users/503_1110499728_d9climb.jpg)
BTW,
Naudet did you get on the Members Only Section? Bunch of new pictures going to be posted. Including a film of pilots view from "Black 3" coming soon.
All the best,
Crumpp
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Ah thanks for posting the images.
The JUMO213A chart Crumpp presents is the chart that was/is responsible for most of the missunderstandings when it comes to power curve/speed curve allignment.
This is a chart for the JUMO213A 1900PS Basis Engine and it is NOT representative for the FW190D9s in service with the LW.
The power curve on this chart that tops out at 2240PS at SL, is very likely the 2.02ata setting.
Note the 2100PS line has not gear changes, why this is so, i yet do not know.
It will not fit to the climb/speed data provided here. I explained that in the LEMB already.
A representative chart for FW190Ds can be found in the PRO document AIR 40/74. It contains a translated DIN A3 format table showing all power settings for the JUMO213A 1750PS Basis engine.
There should also be an orignal german power chart in AIR 40/74, showing not only engine power (sadly missing the 1900PS line)but also exhaust thrust information.
@Crumpp: Not lately will see if i find the time on the WE. Private issues take up most of my attention currently. Allowing me only to look through the forums from work. And at work i don't have the link to the members section. :)
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Crumpp, your Dora speed chart is just the chart I posted, there is the misterious curve 3 (sonder Notleistung mit A lader Bodenmotor? Note that this power setting is not shown in the Jumo chart) with 397mph at sea level.
Naudet also indicates that these are calculated curves (I dont find much sense on calculated curves as late as March 45).
Based on TAM reports, Naudet indicates that maximum allowed ata was 1.8 (in fact 1.81) for Dec 44, but there is no more info about allowed ata, for example, for March 45.
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Mando, i can guaranty you that those charts are calculated, cause i not only own the graphs themself but also the accompanying pages which show the calculations. And before Byran removed the originals from his D9 page, those pages were also available there.
If i remember correctly the entire report can be found in the Smithsonian archive.
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Naudet, calculated or not, there is something named "sonder Notleistung mit A lader Bodenmotor" or something like that (hardly readable). I suppose this is not a "calculated" powersetting, but an actual powersetting. Question would be whether this was operationally allowed during 1945.
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Mando, we are kinda beating a dead horse hear. The curves are all calculated.
It doesn't matter that the power settings did exist (in case for curve 1, 3 & 5) or where a proposal or may have existed.
I draw a very straight line between documented facts and "wishful thinking".
D9s using 2.02ata belongs in the "wishful thinking" category, as with the current source situation it is not possible to prove the testing of such a setting nor the operational use.
If in the future documents turn up that show such a power settings as operational, i will be the happiest Dorphile around and i surely will search for them in the archive.
But unless i have it black on white i will not speculate.
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Hallo Naudet:
Interesting work. Could you cut to the chase for me and describe, in your view, that curve which best represents performance of the 190 D in operational service? Thanks. I've found very similar issues with late 109s as you have encountered with the 190 Ds.
Mike
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Hi Mike, check your PM box in the allaboutwarfare boards.
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Hi Mike,
>Could you cut to the chase for me and describe, in your view, that curve which best represents performance of the 190 D in operational service? Thanks.
Have a look at this:
http://hometown.aol.de/HoHunKhan/Fw190D-9Analysis.gif
The blue curve is extrapolated from flight tests, combining the drag factor of a Fw 190D-9 tested in a close to finalized configuration with a sub-standard engine with the power curve from a standard engine.
(It's conservative as the substandard engine is assumed to give full power albeit at a lower full throttle height.)
So the blue curve is a pretty realistic estimate of minimum Fw 190D-9 performance with a 2100 PS (MW50 injection) engine without bomb rack.
Curve 4 is the Focke-Wulf estimate for a Fw 190D-9 with a bomb rack. That's quite a bit faster than my extrapolation, but it makes sense as the Focke-Wulf estimate probably includes the engine compartment seal that the aircraft I based the blue curve on didn't have. I believe Naudet could find no documentation on whether this seal was ever fitted to operational aircraft.
Based on curve 4 and my rendition of it (note slight deviation at low altitude), I have tried to match curve 3 by increasing engine output.
I found that I needed 2400 HP at sea level to achieve curve 4 performance. (Some guesswork involved, but it shows the order of magnitude.) Higher power also yields higher exhaust thrust, which is not indicated in the power curve but plays a big role, too.
My conclusion from this analysis is that curve 3 probably is for a Jumo 213A engine that is run at such a high boost that it doesn't use low gear because low gear full throttle height is below sea level.
Whether such an engine was ever built is not clear, but in my opinion it's highly unlikely that it ever saw operational use. Von Gersdorff et al. list a Jumo 213S engine that was a project for low full throttle heights, yielding a maximum power of 2400 HP, which looks like it could be the engine curve 3 is based on.
Regards,
Henning (HoHun)
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Hello HoHun:
Thanks for sharing your analysis. Its very nicely thought out and concisely presented. Strikes me as being perfectly plausible. I have a much clearer picture now of the factors that you fellows have been grappling with in your deliberations. That's strong performance...
Regards,
Mike
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Originally posted by Naudet
but also the accompanying pages which show the calculations.
Naudet, these calculations use real plane/engine data as input parameters, or parameters are estimate values?
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Hi again,
http://hometown.aol.de/HoHunKhan/Fw190D-9Analysis.gif
>I found that I needed 2400 HP at sea level to achieve curve 4 performance. (Some guesswork involved, but it shows the order of magnitude.) Higher power also yields higher exhaust thrust, which is not indicated in the power curve but plays a big role, too.
>My conclusion from this analysis is that curve 3 probably is for a Jumo 213A engine that is run at such a high boost that it doesn't use low gear because low gear full throttle height is below sea level.
I'd like to suggest a slightly amended interpretation of the data we have in order to eliminate some of the "guesswork" I mentioned above. My guess was that the engine in question had the same high-altitude characteristics as the standard Jumo 213.
In order to get the high-altitude speed of my extrapolation to match the high-altitude speed of curve 3, I assumed that the curve 3 aircraft had somewhat more drag at the same power, and worked from there.
My new suggestion: The curve 3 aircraft has the same drag as the standard Dora, but the supercharger gearing has been changed to operate the supercharger at a lower speed, yielding better low-altitude power at the cost of decreased high-altitude performance.
(This is comparable to what was done to the Spitfire LF V with "cropped" supercharger, though in a slightly different way.)
It might be possible to confirm that from looking at the boost levels, though I don't have good data on these.
I admit the difference to my previous interpretation is somewhat subtle, but I think it's a progress anyway :-)
Regards,
Henning (HoHun)
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Originally posted by HoHun
I found that I needed 2400 HP at sea level to achieve curve 4 performance. (Some guesswork involved, but it shows the order of magnitude.) Higher power also yields higher exhaust thrust, which is not indicated in the power curve but plays a big role, too.
I´m convinced that it is for 2600PS. The difference of 2400 to 2240PS is not enough to give the extra power by exhaust thrust which would be necessary to reach 640km/h. Furthermore, due to the higher critical altitude compared to curve 2, you lose compared to the first stage of curve 2 power in the supercharger. Additional losses due to higher mach number all over the aircraft makes 2400PS look too low also.
In the book "Flugmotoren and Strahltriebwerke" 2600PS is mentioned as a projekt in the last days, i´m sure that curve 3 is for that project.
niklas
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Hi HoHun:
>"The blue curve is extrapolated from flight tests"
Flight tests of which aircraft? What speeds were achieved at what boost?
Thanks.
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Niklas, the document i mentioned in the AAW boards include curves for a FW190D9 with a JUMO213 using C3 fuel. Those speedcurves match with the powercurves and power seetings listed on the JUMO213 chart with the 2240PS curve. That D9 was calculated for roughly 620km/h SL using C3 + MW50 injection.
And none of the Junkers doc i found in Munich ever mention 2600PS as the next projected power for the JUMO213. "Flugmotoren und Strahltriebwerke" is a little bit of in that regard.
The most promising engine according to Junkers was the JUMO213J, an engine with four valves technique and a rated power of ~2400PS@3700rpm@1,6ata. That engine ran succesfully on the benches btw.
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Hi Niklas,
>The difference of 2400 to 2240PS is not enough to give the extra power by exhaust thrust which would be necessary to reach 640km/h.
Note that curve 4 sea level speed is achieved at 2100 PS, so curve 3 benefits from a 14% shaft power increase, not from a 7% power increase as you assume.
(Naudet found out that we had always used the wrong power curves originally, that's why we had so many problems making it fit.)
>Furthermore, due to the higher critical altitude compared to curve 2, you lose compared to the first stage of curve 2 power in the supercharger.
Curve 2 actually is for C3 fuel - I'm basing my estimate on curve 4 which is based on B4 fuel, just as curve 3.
I'd guess the better performance evident in curve 2 is probably due to using a higher compression engine with the same boost as curve 4, but I haven't thought too hard about it yet :-)
>Additional losses due to higher mach number all over the aircraft makes 2400PS look too low also.
Definitely not :-) Mach number at sea level is only 0.55, far below the critical realm. Curve 3 tops out at Mach 0.60 at around 3600 m.
(The Mach-induced loss of propeller efficiency is figured in by my spreadsheet, and it does in fact play an important role. Before I included it, I actually thought 2100 PS should be enough for 640 km/h, but I was wrong there.)
>In the book "Flugmotoren and Strahltriebwerke" 2600PS is mentioned as a projekt in the last days, i´m sure that curve 3 is for that project.
I'm pretty sure my calculation is accurate enough to rule out 2600 PS. I got within 1% of the flight test speed data, so for a single point, I should be within 3% of the power. So it's really 2400 PS +/- 70 PS - and that's the worst case error, I have a complete speed over altitude curve instead of a a single data point after all.
The same book you quoted also mentions the Jumo 213S with 2400 PS, and in my opinion, there can be no doubt that this is our curve 3 engine.
Regards,
Henning (HoHun)
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Hi Mike,
>>"The blue curve is extrapolated from flight tests"
>Flight tests of which aircraft? What speeds were achieved at what boost?
Here's the full story of the analysis:
http://p069.ezboard.com/fluftwaffeexperten71774frm9.showMessage?topicID=372.topic
I used flight tests of three different aircraft with end-numbers 002, 006 and 043.
I don't have the boost figures ready because the Jumo 213 was not regulated for constant boost, but for constant charge mass, making boost a parameter of secondary importance. (For example, high gear and low gear boosts were markedly different, and the maximum boost varied even below full throttle height.)
Maybe Naudet can help with the exact figures?
Regards,
Henning (HoHun)
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Naudet posted this over on Butch's AAW2:
There it was a package from the NASM, truely amazing as i ordered just four weeks ago.
And the day got even better when i quickly read a frist time through the pages, cause they not only contained the performance numbers/curve i expected. No there was testflight data for the FW190D9 Wk.-Nr. 210 002 with both "Erhöhte Not-/Startleistung" and with MW50 injection!
We finally have it, real flight test speeds for a Dora with the Special Emergency power settings.
Last I read he was busy with real life but once he gets settled he said he would post some info...
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Don't think this is hijacking the thread since it's D9 related. I came across a used copy of Dietmar Hermann's book on the FW 190 "Long Nose"
I assume this is the book Naudet is referring to up thread a ways as a good source on the D9-D13.
A couple of questions after having gone through it.
My impression was that there were very few if any D12s that made it to combat units and only a couple of D13s including the surviving Yellow 10.
Is this a fair assumption?
Also, how many D11s were produced and saw combat? I couldn't find that info in the book
I was also surprised to read about the test flights flown by German pilots in the D13 including the one against the Tempest a month after the war was over.
First to admit my LW knowledge is far below my RAF and USAAF knowledge, but always trying to learn more
Dan/CorkyJr
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D13 or 152, encountered tempest post-war?
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Originally posted by moot
D13 or 152, encountered tempest post-war?
RAF had a German pilot fly Yellow 10, the only surviving D13 against a Tempest.
Pilot quoted in Hermann's book on the 190 D series
Dan/CorkyJr
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Yes, i am pretty busy with RL issues currently, but i just want to jump in an give a couple of answers from memory i can write down in 5 mins.
Henning is indeed correct that JUMO213 uses charge mass and not boost for power control. Boost pressure varies because of this with temperature and so on.
But the rough figures for a JUMO213A with 1 : 6,5 compression ration and rated at 1750PS are the following:
Climb & Combat 1620 PS ~ 1,4 ata
Take-off/Emergency 1750 PS ~ 1,5 ata
Increased Emergency 1900 PS ~ 1,7 ata
MW50 injection 2100PS ~ 1,78 ata
I have not picked out all data for the next developement steps of the JUMO from the documents yet, but Junkers went multiple ways to increase power. One was with high quality fuel (C3) by using a higher compression ration of 1 : 8,5, others were just higher boost pressure, than there were also RPM increases or a even combination of ways. Its a complex issue, because some engines don't even got a regular designation.
And to give a quick glance on the MW50 test, Wk.-Nr. 210 002 reached speeds of 570-580 km/h with Erhoehte Notleitung and 590-595km/h at SL using MW50, without ETC504 attached and a puttied and polished surface.
In a later test were a gap between engine and wing was covered, 002 managed 608km/h at SL using MW50.
But all tests were done using underperforming engines, mentioned in both FW and Junkers documents and so they approve Hennings oppion that the engine of 002 was somewhat "bad". He was right, because the first serial production chargers did not reach intended full boost altitude and airflow, according to Junkers reports of benchtests with there JUMO213 engines from the first serial production batch.
And funny to note, comparative test with Wk.-Nr. 210 001 with standard factory surface finish reached the same speeds as 002. FW was a bit curious why the higher quality surface finish of 002 did not show in better performance and were keen to investigate that issue further.
The conclusion of FW was that with engines performing to the published figures and good factory finish a serial production D9 will reach the calculated performance figures.
About D11/D12/D13, those planes were really only around in penny pocket numbers. Maybe ~50 if you take all three together. Problems here were mainly that the JUMO213E/F never got produced in numbers. You can skip them for any comparison of wartime operations. But it should be mentioned that below ~6000m the D9 performs as good or even a tad better than those three, above that alt the two stage three gear of the JUMO213E/F will give them a huge performance advantage over the D9.
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Originally posted by Naudet
But all tests were done using underperforming engines, mentioned in both FW and Junkers documents and so they approve Hennings oppion that the engine of 002 was somewhat "bad". He was right, because the first serial production chargers did not reach intended full boost altitude and airflow, according to Junkers reports of benchtests with there JUMO213 engines from the first serial production batch.
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The conclusion of FW was that with engines performing to the published figures and good factory finish a serial production D9 will reach the calculated performance figures.
Do you actually have the evidence that the production Jumo 213A reached intended full boost altitude and airflow during war? At least in the case of the DB 605, the tested planes typically did not reach claimed FTH.
gripen
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Originally posted by gripen
Do you actually have the evidence that the production Jumo 213A reached intended full boost altitude and airflow during war? At least in the case of the DB 605, the tested planes typically did not reach claimed FTH.
gripen
Source my dear?
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Thanks HoHun and Naudet! Nice work guys :)
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Originally posted by Kurfürst
Source my dear?
All Bf 109G flight tests I have (more than 30 planes tested) vs DB factory data (published in "Suomen Ilmailuhistoriallinen Lehti").
gripen
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You like to speak in absolute extremes. 'All, never, always'.
here`s the finnish curves of MT 215 (109G-2) :
http://www.onpoi.net/ah/pics/users/715_1118410910_finnishbf109g-2mt215_climb_testat1.3ata.jpg
And the official DB power curves :
http://www.onpoi.net/ah/pics/users/715_1118410819_db605agraph.jpg
The offical FTH of 5.7km corresponds nicely to the test.
just the usual grinoodleh claim again. :D
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Umm, geez - there must be a GL/C-E2 sheet for a 190 D-9? I don't recall having seen one, that's odd. At least that would give some reference points....
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Originally posted by Kurfürst
You like to speak in absolute extremes. 'All, never, always'.
here`s the finnish curves of MT 215 (109G-2) :
http://www.onpoi.net/ah/pics/users/715_1118410910_finnishbf109g-2mt215_climb_testat1.3ata.jpg
And the official DB power curves :
http://www.onpoi.net/ah/pics/users/715_1118410819_db605agraph.jpg
The offical FTH of 5.7km corresponds nicely to the test.
Actually the MT-215 data is a good example if you compare it with the DB factory data. The curves I'm talking about contain static and dynamic MAP as well as how the MAP changes above the FTH.
Originally posted by Kurfürst
just the usual grinoodleh claim again. :D
Is there a remote possibility that you could discuss without personal attack?
gripen
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Hi Naudet,
>But the rough figures for a JUMO213A with 1 : 6,5 compression ration and rated at 1750PS are the following:
>Climb & Combat 1620 PS ~ 1,4 ata
>Take-off/Emergency 1750 PS ~ 1,5 ata
>Increased Emergency 1900 PS ~ 1,7 ata
>MW50 injection 2100PS ~ 1,78 ata
I'd add that on the 006 test sheet, Climb and Combat power (3250 rpm, 1780 PS at sea level) is shown to be achieved at 1.47 ata in low gear and 1.64 ata in high gear.
>One was with high quality fuel (C3) by using a higher compression ration of 1 : 8,5
I'd suspect that's the curve 2 engine.
>In a later test were a gap between engine and wing was covered, 002 managed 608km/h at SL using MW50. But all tests were done using underperforming engines, mentioned in both FW and Junkers documents and so they approve Hennings oppion that the engine of 002 was somewhat "bad".
On the other hand, 006 and 043 had perfectly good engines. All tested aircraft had higher drag than the curve 4 aircraft, though.
The interesting discovery you now made is that 002 was brought up to a drag condition slightly superior to the curve 4 aircraft later, and 001 shared the same low drag with s standard finish.
Did 002 reach the quoted 608 km/h @ 0 km with a good engine? If it was the same sub-standard engine it had earlier, all the filling and polishing might have done it some good after all :-)
Regards,
Henning (HoHun)
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Hi Kurfürst,
>here`s the finnish curves of MT 215 (109G-2) :
Hm, to keep the unavoidable thread creep to a minimum, could you please open a separate thread for the Me 109 issue? Thanks in advance! :-)
Regards,
Henning (HoHun)
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Hi again,
>My new suggestion: The curve 3 aircraft has the same drag as the standard Dora, but the supercharger gearing has been changed to operate the supercharger at a lower speed
I've got a new and even better idea now: Curve 3 is achieved with standard supercharger and supercharger gearing, but with reduced compression.
As the C3-engine shows, Junker was varying the compression to adopt the engine for different altitude bands, so reducing compression to get a low-altitude engine would be the obvious technique.
Regards,
Henning (HoHun)
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Originally posted by gripen
Actually the MT-215 data is a good example if you compare it with the DB factory data. The curves I'm talking about contain static and dynamic MAP as well as how the MAP changes above the FTH.
Actually the MT 215 makes your claim totally silly, but doh, facts do not bother you much... but, as HoHun suggested, if you are so keen sharing your ideas with others about the virtually endless list of DB/109 faults and failings, why dont you do it in a seperate thread and refrain here from spreading nonsense you dont back up later at all...
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Originally posted by HoHun
Hi again,
I've got a new and even better idea now: Curve 3 is achieved with standard supercharger and supercharger gearing, but with reduced compression.
Regards,
Henning (HoHun)
What I am wondering about is why curve 2 (Sonder/C3) and curve 4 (sonder/B4+MW) differ from each other..? I`d rule out different boost as it`s appearing on the whole altitude range.
ETC present/removed? Any idea?
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Originally posted by Kurfürst
Actually the MT 215 makes your claim totally silly, but doh, facts do not bother you much... but, as HoHun suggested, if you are so keen sharing your ideas with others about the virtually endless list of DB/109 faults and failings, why dont you do it in a seperate thread and refrain here from spreading nonsense you dont back up later at all...
Well, it does not matter what I tell you, you want to keep your opinion. Could you please:
a. Get the article and check if what I say is true.
or
b. Ignore my postings if you don't like them.
or you can also do both.
gripen
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Checked Monogram close up on Ta 154 and also there is claims about the Jumo 213A not giving claimed performance.
gripen
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Checked Monogram close up on Ta 154 and also there is claims about the Jumo 213A not giving claimed performance.
Probably not much different from the Mustang Pilots claims of the aircraft not reaching factory performance. Of course the Mustang was very dependant upon "fit and finish" unlike the FW-190.
Given field conditions, manufacturing defects, I have no doubt some FW-190's did not reach factory performance levels. That is a logical and in all probability a true statement.
To blanket classify every FW-190 or even the majority as substandard and unable to reach factory stated performance though is hardly logical. A vast conspiracy to decieve the RLM would have to exist within the RLM test pilots, Focke Wulf, and the Luftwaffe. Frankly it is a silly notion.
All the best,
Crumpp
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Hi Kurfürst,
>What I am wondering about is why curve 2 (Sonder/C3) and curve 4 (sonder/B4+MW) differ from each other..? I`d rule out different boost as it`s appearing on the whole altitude range.
That's probably the result of the different compression.
Remember that the boost pressure alone is only half the story - the supercharger compresses the intake air, but the piston compresses the air even further (actually, it does the lion's share of the compressing).
You want high charge pressure in the cylinder at the moment combustion starts - boost pressure outside the cylinder doesn't really mean anything.
Accordingly, with B4 + MW50 and standard compression, you'll get a standard power curve except in those regions where you can use MW50 to increase the boost pressure as long as your MW50 lasts.
If you have C3 available, you can increase combustion chamber pressure by some amount without having to worry about running out of MW50. That means you can increase the pressure in the cylinder - either by increasing the boost pressure or by increasing the compression.
The drawback of increasing the boost pressure is that it will only work below the original full throttle height, unless you change the supercharger or the supercharger gear ratio. Increasing compression, on the other hand, will give you a higher full throttle height with the same supercharger.
(Why not build a high-compression engine entirely without supercharger and let the piston do all the compressing? In WW1, engines like that were actually used, but they were less efficient than the supercharged engines that were introduced later.)
So we seem to have three different compression ratios with the same supercharger in our Focke-Wulf chart:
Curve 4: B4 + MW50, standard compression
Curve 2: C3, high compression, probably the 1 : 8,5 Naudet quoted
Curve 3: B4 + MW50, low compression
In fact, the curve 3 description is "Sondernotleistung mit A-Lader als Bodenmotor" = "special emergency power with A type supercharger as dedicated low altitude engine".
So it was MW50 injection, but the standard supercharger of the Jumo 213A, and the engine was turned into a dedicated low altitude engine by reducing the compression.
It's all logical, don't know why it took us years to figure out ;-)
Regards,
Henning (HoHun)
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Hi Crumpp,
>To blanket classify every FW-190 or even the majority as substandard and unable to reach factory stated performance though is hardly logical.
I'd like to add that out of the 002, 006 and 043 aircraft, 002 was the only one with an engine that didn't match the Jumo 213A engine chart. The 006 and 043 tests matched the Jumo charts quite precisely.
Regards,
Henning (HoHun)
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Originally posted by Crumpp
Probably not much different from the Mustang Pilots claims of the aircraft not reaching factory performance.
Monogram Close up on the Ta 154 seem to be quite well done book. Author (Jay P. Spenser) seem to have large amount of flight report from Fw and he also interviwed Sander and other FW personel. As an example he mention that he had complete flight reports of the Ta 154 V1. In the case of the Jumo 213A not delivering expected performance, author quotes pretty much directly a FW report.
Originally posted by Crumpp
Given field conditions, manufacturing defects, I have no doubt some FW-190's did not reach factory performance levels. That is a logical and in all probability a true statement.
We have here at least four separate reports where the Jumo 213A did not deliver expected performance and apparently no evidence that it actually could deliver expected performance. The test on 002 with MW 50 (reel 3481 in NASM) seem to be dated March 1945 and the Jumo 213A had been in quantity production about a year that time so the engine was probably quite standard.
Originally posted by HoHun
I'd like to add that out of the 002, 006 and 043 aircraft, 002 was the only one with an engine that didn't match the Jumo 213A engine chart. The 006 and 043 tests matched the Jumo charts quite precisely.
Actually not true, the 043 had lower FTH but HoHun claims that
"Daimler-Benz made two slight simplifications with regard to the diagram, drawing straight through the supercharger gear change, and slightly underestimating full throttle height."
In other words HoHun blames DB for poor match.
The 006 is so much slower than others that it is possible that it actually did run at lower MAP than the 002 and 043. That also explains higher FTH.
gripen
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Ah... Just noted Naudet's post in the LEMB:
"And yes, 006 was used early with an "untuned" engine and a D12 airscrew.
As far as i understand the report "untuned" actually means an engine that was not put through several testflights to ajust boost pressure altittude and so on."
That pretty much confirms that the engine of the 006 might had been running at lower MAP and therefore it could reach higher FTH.
gripen
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The question whether the charger of the JUMO213A reached the proposed performance can not be answered currently.
Complains about lower FTH are written down in the Report of Nov '44 and it was ordered to check the chargers for production deficiencies.
Actually with the tests the problems are that multiple engines where used in each plane. FW noted the characteristics of those engines varied somewhat.
To be honest, while reading the tests i got the impression FW was not vary satisfied with the overall performance/quality of the JUMO213.
About the planes: 001 & 002 had the "Fahrwerksrestabdeckungen", while 006 did not have them. That might explain why 006 was a draggier airframe, it was not as "smooth" as the earlier maschines.
The tests with serial production planes lasted from around August '44 up to Feb/March '45. During March '45 FW send in a report summarizing all results from the D9 tests. Thats why you have so many tables with late dates.
Even though the D9 is by far my most favourite plane of WW2 i must admit that the overall picture the documents produce at the moment is that serial production planes were slightly underperforming due to engine problems.
If those problems could be solved cannot be answered yet.
I know these facts will heat up the discussion about plane performance in AH and i know even before this day ends the first voices will call for a performance reduction of the FW190D in AH.
But i would like to remind you all when rating the FW190D as a historic fighter plane, of the following: In AH +/- 5mph Topsspeed
really make a difference, cause you excatly know what your opponent is capable of, this was not the case in WW2 were the performance from plane to plane varied slightly and you only had a brief idea of the peak performance of you adversary.
P.S.: @Gripen the DB tests is a very odd one, it seems DB was using wrong data. They reported that Wk.-Nr. 210 043 engine was running at 1900PS, but that was not the case. Reported boost pressure, FTH, and speed of 043 show that the flights were done using take-off/emergency of 1750PS@1,5ata and not Erhoehte Notleistung.
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Hohun says:
So it was MW50 injection, but the standard supercharger of the Jumo 213A, and the engine was turned into a dedicated low altitude engine by reducing the compression.
Makes perfect sense.
Gripen says:
We have here at least four separate reports where the Jumo 213A did not deliver expected performance and apparently no evidence that it actually could deliver expected performance. The test on 002 with MW 50 (reel 3481 in NASM) seem to be dated March 1945 and the Jumo 213A had been in quantity production about a year that time so the engine was probably quite standard.
No different from the investigation into the Mustang's problems. It seems that the mustang could not achieve stated performance unless the machine had a very good fit and finish. Something extremely hard to achieve in service use and something a frontline unit is unlikely to be able to maintain. No solution presented itself during the war. In fact the debate still rages today!
The tests with serial production planes lasted from around August '44 up to Feb/March '45. During March '45 FW send in a report summarizing all results from the D9 tests. That’s why you have so many tables with late dates.
Hey Naudet!
Interesting however I am not surprised.
Without a doubt they were investigating ways to increase performance. Additionally quality control was always a concern in wartime German aircraft manufacturing. I have several reports on sabotage during production and investigation into substandard production of subcomponents of the FW-190A throughout the war. Byproduct of the use of slave labor by the Nazi's and wartime philanthropy. In fact we are working a display at the museum as parts of our aircraft were built with slave labor. The German aircraft industry was very sensitive to quality control issues. In fact, Focke Wulf maintained "quality control" example aircraft which were flown to various subcontractors’ assembly lines to demonstrate the standards Focke Wulf Bremen expected.
This was also a common practice with most aircraft manufacturers worldwide.
Keep in mind, performance tests were also an ongoing fact of life in fighter development in any air force as well. Designs were not static and for a manufacturer to not continue development was to invite both economic ruin for the company and defeat for the country.
As you well know, it's a long chain of events in the mass production of a complicated machine. Any weak link can lower performance or lead to premature failure. If this was not the case, new car dealerships would never need a service department!
BTW I have some goodies coming that may speak directly to this issue. I located the engineering development team meeting minutes from Focke Wulf Bremen with the Geschwaders from Mid-1944 thru March 45. These are meeting between the pilots, mechanics, and FW design team to get feedback on the aircraft performance in combat as well as suggestions for technical improvements. Logistics’ is also discussed. The previous reports I have are broken down by Luftflotte/JG.
All the best,
Crumpp
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Originally posted by Naudet
I know these facts will heat up the discussion about plane performance in AH and i know even before this day ends the first voices will call for a performance reduction of the FW190D in AH.
I'm here merely promoting an idea that there is a remote possibility that real flight tests might give better picture of the performance of the plane and engine than any calculation or factory spec.
Regarding the performance of the AH Fw 190D, I can honestly say that no one else here can be more satisfied than me with it's current performance (and it's same in the case of the AH Bf 109G-2).
gripen
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Gripen, i fully agree with you. Real flight tests are giving the best picture, cause they are the only ones were production quality etc. shows it's effect.
And if it shows that the productions deficiencies of the JUMO213A were an issue due to the entire FW190D production, i myself would agree with a reduction of AHs D9 performance.
And as Crumpp mentioned in the late years of war the increasing amount of slave labor lead to problems with the quality control.
Additionally many planes/engines were license produced and those factories often did not show the same care for the production process as the orignal manufacture.
This is the case for the JUMO213A i.e. the first serial production batch that showed deficiences were not build by Junkers itself.
And for the FW190D it was known that planes from FW's own factory in Sorau were especially good with a very smooth surface finish.
My maininterest in this is - after years of research - no longer to promote a position of "this is the best plane", but to show that german aircraft specifications and design processes were based on a reliable and realistic data base and not some kind propaganda.
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My maininterest in this is - after years of research - no longer to promote a position of "this is the best plane", but to show that german aircraft specifications and design processes were based on a reliable and realistic data base and not some kind propaganda.
They very much were based on reliable realistic data. Many of today's innovations, from developing alloys such as Elektron, to today's industry leaders such as Drager, BMW, DB, and many others were leading their industry back then as well.
Those documents arrived in the mail just a few hours ago. There are several entries regarding the Jumo 213A and the Dora.
I will post scans on AAW in the "FW190 discussion group" for you.
The "my plane is best" agenda permeates these boards and is exactly why I am not keen to post nearly as much as in the past.
There is always someone with "game" issue or agenda to push to include downright data manipulation.
All the best,
Crumpp
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Crumpp,
What investigation are you referring to? North American Aviation was well known for extremely good fit and finish. VIII Fighter Command ground crews were equally well known for the care they took of their charges. Polishing, waxing and repainting were the norm for 8th AAF fighters.
There seems to be a conventional wisdom which states that the Mustang suffered more than other fighters from operational use. That CW is wrong. I suspect it is based on the mistaken belief that the Mustang relied on actual laminar air flow over the wing to achieve its performance. Not true. As you no doubt know, the Mustang's sterling performance resulted from its radiator design and the laminar profile wing's excellent drag performance at high speed. No production Mustang wing ever achieved true laminar flow.
The fact is that both USAAF and RAF testing numbers met or exceeded the numbers supplied by NAA. Even Mustang III FB377, which was received by the R.A.E. from 316 Sqn with a truly wretched surface condition (paintwork described as “in very poor condition” with eight coats of “badly chipped” paint on the wings), achieved 383 mph at SL fully combat loaded at +25 lbs boost. The much smaller Bf 109K-4's best-case estimated sea level performance was 6 mph slower with slightly more HP. 8th AAF historian Roger Freeman states that VIII FC squadron service P-51D’s exceed 430 mph in level flight at half combat fuel load.
Originally posted by Crumpp
Makes perfect sense.
No different from the investigation into the Mustang's problems. It seems that the mustang could not achieve stated performance unless the machine had a very good fit and finish. Something extremely hard to achieve in service use and something a frontline unit is unlikely to be able to maintain. No solution presented itself during the war. In fact the debate still rages today!
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What investigation are you referring to? North American Aviation was well known for extremely good fit and finish. VIII Fighter Command ground crews were equally well known for the care they took of their charges.
I am refering to an 8th AF investigation brought about by complaints from it's P51 squadrons that the aircraft was not reaching stated factory performance.
Are we really going to deny the "laminar flow" debate or enter it? Aeronautical engineers have been arguing for decades now on this issue.
Polishing, waxing and repainting were the norm for 8th AAF fighters.
There is a reason it became the norm. It takes a lot of extra work to polish a plane. It is a difficult to maintain finish in a frontline unit.
It never had any weapon reliability issues either!
All the best,
Crumpp
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I will post scans on AAW in the "FW190 discussion group" for you.
Crumpp, i think i don't have access to that subsection of AAW currently.
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You should. Your on the member list.
All the best,
Crumpp
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LRRP2,
The NACA and North American say that laminar flow was important to Mustang Performance.
The performance achieved under controlled conditions could not be replicated under field conditions.
In application, the laminar flow airfoil was used during World War II in the design of the wings for the North American P-51 Mustang, as well as some other aircraft. Operationally, the wing did not enhance performance as dramatically as tunnel tests suggested. For the best performance, manufacturing tolerances had to be perfect and maintenance of wing surfaces needed to be thorough. The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories. Still, the work on the laminar flow wing pointed the way to a new family of successful high-speed airfoils. These and other NACA wing sections became the patterns for aircraft around the world.
http://www.hq.nasa.gov/office/pao/History/SP-4406/chap2.html
So yes, the P 51 Mustang did not achieve the same performance in the squadrons as it did under controlled test flight conditions.
All the best,
Crumpp
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Originally posted by Crumpp
Operationally, the wing did not enhance performance as dramatically as tunnel tests suggested.
Crumpp,
Absolutely. Fortunately for Mustang squadrons, NAA and USAAF performance numbers were not derived from wind tunnel testing. No P-51 Mustang produced by North American Aviation, prototype or production, experienced true laminar flow in actual flight- including those used for testing. Lee Atwood himself attributed the Mustang’s speed performance to the radiator design and very low airframe drag, not laminar flow which he knew was unobtainable using contemporary production methods.
Was the P-51 subject to performance degradation due to surface wear and tear? Certainly- just like every other aircraft. The six coats of "very poor" paintwork on Mustang III FB377’s wings resulted in an estimated 12 mph speed loss compared to speeds achieved after a partial restoration of its paintwork. Considering the 'as received' condition, 12 mph hardly seems excessive.
Do you have specifics on this supposed USAAF investigation? It sounds suspiciously like the alleged 'RAF Hendon' test which has already been debunked on this board. I have dozens of 8th AAF-specific works, none of which relate a single instance of VIII FC squadrons or pilots being disappointed with operational Mustang performance. Quite the contrary, in fact.
And yes, the P-51B/C obviously had weapon stoppage problems early on. Those problems had been largely dealt with (though not eliminated) by Summer, '44 . The P-51D had no such problems.
Anyway, I don't want to hijack this thread any further...
Regards,
Brent
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Considering the 'as received' condition, 12 mph hardly seems excessive.
In fact it seems very remarkable if it is your contention a 12 mph gain was average for the Mustang due to surface finish.
We know cooling drag is part of the total drag component of a reciprocating engine powered aircraft.
The P51's low overall drag is in part due to the design of the cooling system.
Take the Bf-109 for instance. Cooling drag makes up a larger percentage of it's total drag picture when compared to the Mustang.
Therefore surface finish should have less of an effect as it can only overcome so much of the total drag.
Yet we see here that large gains where made in overall speed for surface conditions.
(http://www.onpoi.net/ah/pics/users/503_1118615248_polished109.jpg)
19 MPH to 25 MPH gained from a wax job is pretty good.
Now lets looks at the opposite end of the spectrum, the FW-190A. A very large percentage of its total drag picture is made up in cooling drag. Hence surface finish had very little to no effect on its overall performance.
(http://www.onpoi.net/ah/pics/users/503_1118616152_smoothing.jpg)
Neither of the German aircraft have laminar flow wing designs either.
So yes, I do find it remarkable that the Mustang only gains a few mph due to surface finish. With the smallest percentage of cooling drag changes in form drag should have a greater effect on performance than an aircraft whose total drag picture is comprised of a much larger percentage of cooling drag.
All the best,
Crumpp
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Originally posted by Crumpp
In fact it seems very remarkable if it is your contention a 12 mph gain was average for the Mustang due to surface finish.
Hello Crumpp,
I make no contention as to average gain to be expected from improved surface finish. The Royal Aircraft Establishment, however, found that Mustang III FB377 gained approx. 12 mph from stripping and repainting two feet of the wings' leading edges and 'rubbing down' the rest of the airframe. The report (AVIA 6/10618) certainly doesn't support the contention that the Mustang suffered performance losses due to surface finish to a larger degree than other aircraft. The R.A.E. states that the improved surface finishes could be "maintained in this final condition without any great difficulty under squadron conditions".
(http://img.photobucket.com/albums/v11/brentce/FB377pg3.jpg)
As for the 30-40 kph increase claimed for the Bf 109, it is quite possible that the claims made in the JG302 document were more anecdotal than empirical. Most ac****s relating to polishing the surfaces of Mustangs, Spitfires and Thunderbolts refer to 'an extra few mph' and not the large increased claimed above.
I'm a little confused regarding your comments on cooling drag vs. parasitic drag. Whether the 190 had larger amounts of cooling drag in no way means that improvements in form drag would have no effect- the 190 suffered from form drag every bit as much as the Bf 109 or P-51. Increased cooling drag comes in addition to drag related to surface slickness, not in lieu of it.
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This report (AVIA 6/10618) certainly doesn't support the contention that the Mustang suffered performance losses due to surface finish to a larger degree than other aircraft. The R.A.E. states that the improved surface finishes could be "maintained in this final condition without any great difficulty under squadron conditions".
I don't see were this report says anything about differences in performance due to finish.
This report simply states the operational squadrons had some pretty rough finishes so they cleaned up the aircraft. They removed the paint from 2 ft on the leading edge and repainted it. The rest they smoothed the finish on.
They due note the seriousness of such a finish on the performance of the Mustang:
(http://www.onpoi.net/ah/pics/users/503_1118622127_mustangfinish.jpg)
And additional modifications so it is hardly representative.
All the best,
Crumpp
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It does in fact state 12 mph due to surface restoration:
(http://img.photobucket.com/albums/v11/brentce/AVIA6-10618Pg4.jpg)
I don't know why FB377 would be more or less representative than any other Mustang in similar condition. That "seriousness" resulted from the fact that the Mustang's paintwork was in "very poor condition" vs. "fairly poor" and "poor" in the case of the Tempest and Spitfire.
Originally posted by Crumpp
I don't see were this report says anything about differences in performance due to finish.
This report simply states the operational squadrons had some pretty rough finishes so they cleaned up the aircraft. They removed the paint from 2 ft on the leading edge and repainted it. The rest they smoothed the finish on.
They due note the seriousness of such a finish on the performance of the Mustang:
And additional modifications so it is hardly representative.
All the best,
Crumpp
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I don't see were this report says anything about differences in performance due to finish.
Obviously I need to be more specific.
I was making a general statement. I already know the report states this aircraft increased performance by 12 mph.
You stated that earlier, LRRP2. No reason not to believe you.
This report does NOT make any specific conclusions about the Mustang performance increases due to finish as I stated.
To spell it out. You cannot say the Mustang is only slightly improved by "fit and finish". As the NACA and North American concluded, you cannot get planned performance out of the Mustang under field conditions. It's performance is greatly effected by it's finish.
I'm a little confused regarding your comments on cooling drag vs. parasitic drag. Whether the 190 had larger amounts of cooling drag in no way means that improvements in form drag would have no effect- the 190 suffered from form drag every bit as much as the Bf 109 or P-51. Increased cooling drag comes in addition to drag related to surface slickness, not in lieu of it.
Cooling drag is part of the total drag and is included when the total drag is determined. The little to no effect of surface condition is a reoccuring theme in FW-190 tests and is well documented.
(http://www.onpoi.net/ah/pics/users/503_1118628914_coolingdrag.jpg)
All the best,
Crumpp
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Hi Crumpp,
>http://www.onpoi.net/ah/pics/users/503_1118628914_coolingdrag.jpg
Quite interesting! What does w/g stand for?
Regards,
Henning (HoHun)
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Hm... If a plane gained 30-40 km/h when the standard finish was puttied and polished, then the standard surface finish must had been very bad.
gripen
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Originally posted by Crumpp
Obviously I need to be more specific.
I was making a general statement. I already know the report states this aircraft increased performance by 12 mph.
You stated that earlier, LRRP2. No reason not to believe you.
This report does NOT make any specific conclusions about the Mustang performance increases due to finish as I stated.
To spell it out. You cannot say the Mustang is only slightly improved by "fit and finish". As the NACA and North American concluded, you cannot get planned performance out of the Mustang under field conditions. It's performance is greatly effected by it's finish.
All the best,
Crumpp
Well Crump, the R.A.E., Boscombe Down, and Wright Field disagree.
What’s your definition of “Planned Performance”? If you mean wind tunnel projections of performance, then you are most likely right. 1940’s production technologies could not produce a surface finish conducive to actual laminar flow. If you mean the NAA/USAAF/RAF figures for clean aircraft performance, then you are almost certainly wrong since reaching the published performance figures didn’t require actual laminar flow. After all, the test aircraft used to generate those numbers, like squadron examples, didn’t enjoy laminar flow to begin with.
Maybe I need to make myself clearer: The commonly quoted figures for actual Mustang performance, not preliminary estimates based on wind tunnel tests, were quite attainable by squadron service P-51's. In fact, the RAE’s 12 mph speed loss due to finish fits very well with Wright Field’s test of P-51B 43-24777 from May of ’44. 43-24777 did 364 mph/67” Hg at sea level in full combat configuration (9,680 lbs) with wing racks. FB377 did 383 mph@SL in the same configuration (but probably 9200 lbs) at 81” Hg. Subtracting the 25-27 mph attributed to the increase from 67” to 81” Hg leaves us with 356 to 358 mph@SL for FB377 at 67” Hg- even less than 12 mph estimated by the RAE. The missing 4-6 mph is probably attributable to the fact that FB377 was likely 400-500 lbs lighter than 43-24777, or even just normal variation in airframes or test conditions.
To spell it out. You cannot say the Mustang is only slightly improved by "fit and finish". As the NACA and North American concluded, you cannot get planned performance out of the Mustang under field conditions. It's performance is greatly effected by it's finish.
You are confusing (or combining) the issues of production quality vs. operational wear and tear. Your conclusion doesn't follow from your premise. The only way it does work is if the Mustang left the factory with a wing capable of true laminar flow. It didn't. Period. No one, including NAA Vice President and Chief Engineer Lee Atwood, believed it did. Did Mustang performance benefit from NAA's high standards for fit and finish? That production quality didn't suddenly disappear in squadron service, however. Like other fighters, paintwork (not overall production quality) degraded in the field, but no more so than other fighters. In other words, paintwork would degrade, but not the underlying production quality of the airframe.
You seem to have a firmly held belief that the Mustang was some how less potent than other fighters under operational circumstances. That's fine, its just that the evidence doesn't support your belief. So far, all you have been able to show is that the Mustang’s wing didn’t achieve the same air flow efficiencies in production as did wooden models in the wind tunnel. You have provided no evidence that production P-51’s were more affected by service wear and tear than its contemporaries. I have provided clear cut evidence that even a heavily degraded surface finish only accounted for a 12 mph speed loss. Like I said, performance numbers were based on actual production finishes, not wind tunnel projections.
The fact is that the Mustang's aerodynamic advantages were based in the cooling design's very effective use of the Meredith Effect, a very slick shape and excellent overall production quality. To what it was not due was actual Laminar Air Flow.
Cheers,
Brent Erickson
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Originally posted by gripen
Hm... If a plane gained 30-40 km/h when the standard finish was puttied and polished, then the standard surface finish must had been very bad.
gripen
Too true...
.
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I have provided clear cut evidence that even a heavily degraded surface finish only accounted for a 12 mph speed loss.
No you have provided one report which sheds no light on this issue. The speed gain is "estimated" not measured and estimated how? The exhaust change can have huge effects both on form drag and engine performance. Adding considerable form drag while increasing power and exhaust thrust. How much these forces changed is unknown in your report.
You can hardly draw conclusions about this aircraft's drag profile for the entire Mustang series.
Your conclusion of small gains does not make sense scientifically given the low total drag of the Mustang.
Again both the NACA and North American say the same thing. The Mustang performance was heavily dependant on fit and finish.
For the best performance, manufacturing tolerances had to be perfect and maintenance of wing surfaces needed to be thorough.
http://www.onpoi.net/ah/pics/users/...coolingdrag.jpg
All the best,
Crumpp
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About drag: Maybe you know already this doc:
http://www.mitglied.lycos.de/luftwaffe1/aircraft/usaaf/P51B_drag.pdf
In Figure 14/15 you can see the influence of dust on the wing. In this particular case drag is increased at low AoA by at least 5%.
This alone raises the question whether flight tests of single machines make sense. I mean when you have bad whether with a lot of dust, you´ll perform easy 30-40km/h worse than on a good day. Fly through a swarm of flies during takeoff, or get some dirt by your wheels, and you lose immediatly 20km/h and so on.
In any case cleaning and polishing the machine, especially after a flight, makes sense.
btw. the laminar flow effect (minimum drag bulge in the polor curve at low AoA) can also be observed in wind tunnel tests on standard airfoils at this time, though not as pronounced compared to a laminar airfoil. I remember to have some german wind tunnel tests in my hand, mentioning it. That little bulge could be seen in the polar curve.
niklas
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Crumpp,
The change in exhaust stacks accounted for a 1 1/2 mph gain. How do I know? Because the airplane was tested after the removal of wing racks and paintwork restoration, and then again after the change of exhaust stacks. the first condition yielded 403.5 mph at sea level and the second 405 mph at sea level. Remember, the RAE were not amateurs at this kind of testing- it is what they did.
In application, the laminar flow airfoil was used during World War II in the design of the wings for the North American P-51 Mustang, as well as some other aircraft. Operationally, the wing did not enhance performance as dramatically as tunnel tests suggested. For the best performance, manufacturing tolerances had to be perfect and maintenance of wing surfaces needed to be thorough. The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories.
This seems to be the basis for your belief that the Mustang was severely compromised in squadron service. As I have pointed out repeatedly, the P-51 didn't require 'tunnel tests' level of finish to achieve the NAA and USAAF speed numbers- the tested aircraft didn't have wind tunnel model tolerances either. Like all other aircraft, the Mustang suffered from operational wear and tear but not, as indicated by AVIA 6/10618, significantly more than other types
Now 'scientifically', I don't think you have any empirical basis for saying that paintwork of a certain condition must account for more than 12 mph in lost speed. Frankly, it sounds more like wishful thinking than science. I do have empriacal data supporting the 12 mph speed loss. If a 12 mph loss isn't enough, how much, 'scientifically', do you believe is appropriate?
Originally posted by Crumpp
No you have provided one report which sheds no light on this issue. The speed gain is "estimated" not measured and estimated how? The exhaust change can have huge effects both on form drag and engine performance. Adding considerable form drag while increasing power and exhaust thrust. How much these forces changed is unknown in your report.
You can hardly draw conclusions about this aircraft's drag profile for the entire Mustang series.
Your conclusion of small gains does not make sense scientifically given the low total drag of the Mustang.
Again both the NACA and North American say the same thing. The Mustang performance was heavily dependant on fit and finish.
http://www.onpoi.net/ah/pics/users/...coolingdrag.jpg
All the best,
Crumpp
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How do you explain the NACA drag test on the P51B Niklas posted. Thanks for posting that Niklas BTW, I had forgotten about that investigation.
It clearly states "good agreement between windtunnel test and flight test".
The report I saw from squadron complaints was in the 8th AF archives. I will be heading back there in a few weeks and will grab a copy of it. I did not get a copy because it was of little interest to me at the time.
All the best,
Crumpp
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How do you explain AVIA 6/10618? I think a report that deals with direct testing of operational aircraft has a lot more relevance to the discussion than a prop-less, unpowered and empty example towed to altitude and dropped over the desert. The truth is that we have controlled tests of an operational Mustang in documented conditions. This test showed that improving the paint surface from "very poor" to something approaching new condition yielded a 12 mph speed gain. Even if the RAE underestimated the amount of speed loss caused by the wing racks (8 mph), they could, at most, be off by a couple of mph. Both the USAAF and RAF found that wing racks cost the P-51 12 mph around 10,000 ft and up to 14 mph above 20-25,000 ft. The RAE says 8 mph at sea level which is certainly *very* close to the actual value.
Just to get this straight: Is it your contention that NAA and USAAF P-51 performance numbers were derived from wind tunnel estimates and not from actual testing of production models? Or is it that you believe the tested numbers were derived from exceptional, custom built examples? You might be able to make that argument for the NAA numbers, but the fact is that the USAAF and RAF always tested from delivered production batches and, in the case of the P-51, the USAAF and RAF data invariably equalled or exceeded the NAA numbers.
Further, do you believe that the P-51 ever achieved actual laminar flow during flight? There really is no debate about that- it didn't. Even in the late 50's the only way to achieve actual laminar flow involved a wierd system of boundary layer vents in the wing and a compressor system to pump air over the wing.
I'll be looking for the 8th AAF report...
Regards,
Brent
Originally posted by Crumpp
How do you explain the NACA drag test on the P51B Niklas posted. Thanks for posting that Niklas BTW, I had forgotten about that investigation.
It clearly states "good agreement between windtunnel test and flight test".
The report I saw from squadron complaints was in the 8th AF archives. I will be heading back there in a few weeks and will grab a copy of it. I did not get a copy because it was of little interest to me at the time.
All the best,
Crumpp
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Crumpp,
An honest question: how much speed, in mph, do you think the average operational P-51 lost compared to published USAAF figures? How many mph do you think the average P-47, Spitfire or Focke Wulf suffered?
Regards,
Brent
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This test showed that improving the paint surface from "very poor" to something approaching new condition yielded a 12 mph speed gain.
Seems they skipped the effect of the new exhaust stubs:
(http://www.onpoi.net/ah/pics/users/503_1118699813_avia6-10618pg4.jpg)
Which would change power, drag, and exhaust thrust.
Is it your contention that NAA and USAAF P-51 performance numbers were derived from wind tunnel estimates and not from actual testing of production models? Or is it that you believe the tested numbers were derived from exceptional, custom built examples? You might be able to make that argument for the NAA numbers, but the fact is that the USAAF and RAF always tested from delivered production batches and, in the case of the P-51, the USAAF and RAF data invariably equalled or exceeded the NAA numbers.
It is my contention that the NACA was correct in its conclusions:
For the best performance, manufacturing tolerances had to be perfect and maintenance of wing surfaces needed to be thorough.
And that the 8th AF experienced this historical fact recorded by the NACA:
The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories.
As with any manufacterer who subcontracts, quality control issues will arise. Especially in the begining when subcontrators are tooling up and learning to make the product.
Add in the difficulties of maintaining the high degree of surface finish the Mustang required to achieve it's stated performance and it is not a surprise that the end users would voice some complaints.
http://www.hq.nasa.gov/office/pao/History/SP-4406/chap2.html
The Mustang was very sensative to surface imperfections as covered in this report which is seeking to make general conclusions about the design and not specific ones about a modified aircraft as in AVIA 6/10618.
The tests results show that the drag characteristics of the test airplane can be predicted with satisfactory accuracy from tests in the Ames 16-foot high-speed wind tunnel of the Ames Aeronautical Laboratory at both high and low Mach numbers. It is considered that this result is not unique with the airplane.
http://naca.larc.nasa.gov/reports/1948/naca-report-916/
All the best,
Crumpp
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An honest question: how much speed, in mph, do you think the average operational P-51 lost compared to published USAAF figures? How many mph do you think the average P-47, Spitfire or Focke Wulf suffered?
It depends on the drag characteristics of the aircraft in question. It is not the same for each aircraft. Some planes make larger gains than others.
That is what I explained earlier with the P&H scans and documents. You should read up more on aerodynamics. It can add some wonderful insights into the history of these aircraft.
All the best,
Crumpp
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Originally posted by Crumpp
Seems they skipped the effect of the new exhaust stubs:
Which would change power, drag, and exhaust thrust.
Crumpp,
I've already posted the information regarding the exhaust stacks. Two tests were conducted after the paintwork was cleaned up- the first before the exhaust stacks were replaced which yielded 403.5 mph at sea level, and one after the exhaust stacks were replaced which yielded 405 mph. +1.5 mph- that is not disputable. If you choose to discount that fact, so be it.
(http://img.photobucket.com/albums/v11/brentce/FB377.jpg)
It is my contention that the NACA was correct in its conclusions:
Yes, but its conclusion was that the quality of airflow achieveable with a wooden 1/3 scale model in a wind tunnel wasn't attainable by production airframes because of limitations in production methods and operational wear and tear. It says nothing regarding squadron performance vs. manufacturer/service test performance. That is a logical leap you have chosen to take, not NACA. After all, the tested aircraft were subject to the same production limitations and quality as any other example. Service test performance numbers were based on production airframes that were pulled at random from delivered production batches.
And that the 8th AF experienced this historical fact recorded by the NACA:
That may, or may not be the case. I supect that when you find the above mentioned report, it is going to be far less damning than you seem to imply.
As with any manufacterer who subcontracts, quality control issues will arise. Especially in the begining when subcontrators are tooling up and learning to make the product.
Add in the difficulties of maintaining the high degree of surface finish the Mustang required to achieve it's stated performance and it is not a surprise that the end users would voice some complaints.
Please make reference to which stated performance. Again, manufacturing defects were already built-in to the service trial numbers.
The Mustang was very sensative to surface imperfections as covered in this report which is seeking to make general conclusions about the design and not specific ones about a modified aircraft as in AVIA 6/10618.
Laminar flow was very sensitive to surface imperfections, prohibitively so. The Mustang's laminar profile wing was less so.
I am a bit befuddled as to why you patently dismiss the results of a professionally conducted and documented service test report, yet extrapolate deep meaning from some general comments that don't specifically address the issue at hand.
I know you don't like to deal in specifics but, again, please tell me just how much slower you think a field worn P-51 should be vs. other fighters in the same condition. I'll settle for a range, but you must be able to quantify this disparity to some degree. It's my contention that any differences would be minor while you seem to believe that they were profound.
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Originally posted by Crumpp
It depends on the drag characteristics of the aircraft in question. It is not the same for each aircraft. Some planes make larger gains than others.
That is what I explained earlier with the P&H scans and documents. You should read up more on aerodynamics. It can add some wonderful insights into the history of these aircraft.
All the best,
Crumpp
Please spare me the condescension.
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Please spare me the condescension.
Honestly I was not trying to be condescending. It is just that you do not seem to understand some of the theory.
Evidenced by your statement below:
I've already posted the information regarding the exhaust stacks. Two tests were conducted after the paintwork was cleaned up- the first before the exhaust stacks were replaced which yielded 403.5 mph at sea level, and one after the exhaust stacks were replaced which yielded 405 mph. +1.5 mph- that is not disputable. If you choose to discount that fact, so be it.
Yes. I have seen this.
Tell me:
How much is lost to extra drag of the exhaust stubs?
How much is gained due to power gains of larger exhaust?
How much exhaust thrust is added over a normal P51?
We know the end result but we do not know the relationship from this graph. Nor was it calculated in the report.
And this statement:
Increased cooling drag comes in addition to drag related to surface slickness, not in lieu of it.
Which I already showed you that cooling drag and form drag are all part of the total drag.
The larger a component is the greater the effect of it's reduction.
Please make reference to which stated performance. Again, manufacturing defects were already built-in to the service trial numbers.
Not likely as evidenced by the NACA report's use of a high quality aircraft submitted for testing by North American.
All the best,
Crumpp
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Originally posted by Crumpp
Honestly I was not trying to be condescending. It is just that you do not seem to understand some of the theory.
Evidenced by your statement below:
Well Crumpp, If I didn't know better I would call that more condescension.
There is no "theory" involved in the fact that you claimed the changes made to the exhaust stacks had an unknown effect of the increaded performance. That statement is patently absurd considering the fact that we know exactly how much extra speed was gained: exactly 1.5 mph. 'Extra Drag' caused by the very slightly larger exhaust stacks sounds like grasping at straws, Crumpp.
If I need to read up on aerodynamics, you need to read up on logic- your statements just don't add up. Sound logic and observation would tell you that that the change in exhaust stacks is irrelevant to the topic at hand: The 12 mph gain in speed from paint restoration occurred before the exhaust stacks were replaced.
Please, quit being obtuse. You have been presented with hard data from an infinitely credible source that you refuse to accept, period.
Reards,
Brent
Oh BTW, all production P-51's were 'high quality'.
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Please, quit being obtuse. You have been presented with hard data from an infinitely credible source that you refuse to accept, period.
It's not being obtuse to take more than one source.
T'Extra Drag' caused by the very slightly larger exhaust stacks sounds like grasping at straws, Crumpp.
The change in performance is known. It is the effect on the forces that is not. Is that hard to understand?
Mute point anyway as this modification did not see production. However my questions clearly showed your lack of understanding of the science.
You still do not understand the relationship of drag forces and want to hold one example up as typical of the entire series.
Explain how the RAE is more credible than the NACA or the manufacturer of the aircraft?
Oh BTW, all production P-51's were 'high quality'.
Sure they were, otherwise the NACA's would not have had to quantify their findings on Mustang performance.
The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories.
http://www.hq.nasa.gov/office/pao/History/SP-4406/chap2.html
All the best,
Crumpp
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Originally posted by Crumpp
It's not being obtuse to take more than one source.
Crumpp,
It is in fact grossly obtuse to take data that directly addresses the issue of squadron service performance and discard it in favor of general comments from another source that only very indirectly address the subject at hand. Obviously, since it doesn't fit your agenda, you have no use for it. Perhaps you should take a more objective approach to selecting and weighting your sources.
Since you can't seem to accept the idea that AVIA 6/10618's expressed purpose was to test the expected performance of average squadron aircraft:
(http://img.photobucket.com/albums/v11/brentce/AVIA6-10618Intro.jpg)
The change in performance is known. It is the effect on the forces that is not. Is that hard to understand?
Please don't lecture me on understanding. You are showing a willful lack of understanding of the information provided to you. There is no mysterious alchemy involved here- no secret science that I am not a party to. Quite simply, a Mustang III (FB377) pulled directly from operational service (316 Sqn) achieved 383 mph at sea level with wing racks in place and a very poor surface condition. That same airplane, at exactly the same power setting, and under the same controlled and corrected test conditions achieved 403.5 mph after the wing racks and the small bracket at the base of the VHF aerial were removed, and the very poor surface condition restored. The Royal Aircraft Establishment at Farnborough, an exceptionally qualified testing institution, attributed 8 mph of the increase to the removal of the wing racks, 1/2 mph to the removal of the aerial bracket and 12 mph to the resoration of the badly degrade paint surfaces. In all other ways the airplane was identical.
Your attempts to obfuscate the results with repeated referrals to the exhaust stubs and resulting exhaust thrust ring hollow, I'm afraid. Further, I'm sure the realization that a well-used squadron service Mustang III with a six coats of badly chipped paintwork was faster than the fastes production Focke Wulf doesn't sit well with you, either.
Your patronizing attempts to convince me that I'm just too thick to understand the forces at work here are just a way for you to avoid directly addressing the findings of the report. The report doesn't support your premise so you want simply to ignore it.
Mute point anyway as this modification did not see production. However my questions clearly showed your lack of understanding of the science.
You still do not understand the relationship of drag forces and want to hold one example up as typical of the entire series.
I'm glad that you have finally accepted that the larger Spitfire-type exhausts fitted are moot to this argument. After all, the increase in speed attributed to the cleaned-up surfaces was determined before the exhaust stacks were replaced. It is you who exhibits a shocking lack of understanding of logic and reason here, Crumpp. And once again Crumpp, it was the Royal Aircraft Establishment, not me, that held this example as representative of the average operational aircraft. For the last time, either tell me why they were wrong and you are right, or finally accept the uncomfortable truth.
Explain how the RAE is more credible than the NACA or the manufacturer of the aircraft?
I never said the RAE was more credible than NACA. Unfortunately for your argument, NACA never performed tests of operational P-51's expressly designed to determine how much speed could be gained in squadron service through a number of quantified actions. The Royal Aircraft Establishment, however, did.
Sure they were, otherwise the NACA's would not have had to quantify their findings on Mustang performance.
You can post that link until you're blue in the face, but that still won't cause the document to say something that it doesn't. You want to believe that it says P-51's taken on charge by the USAAF and RAF were of a much lower quality than the ones experimented on by NACA. It doesn't. It simply states that the manufacturing technologies of the day were not capable of producing the type of surface smoothness that was required to achieve laminar air flow in the wind tunnel. Even if the production tolerances were capable in that manner, it wouold have been impossible to maintain that surface quality in operational surface. Is it suprising that a production line, even a very capable one, was not capable of assembly hundreds of parts made from different materials with the same level of precision as the 1/3 and 1/4 scale hand-made mahogany and metal wind tunnel models. Even these custom creations with five layers of hand-rubbed lacquer only achieved laminar flow in brief fits and starts. What's so hard to understand about that?
Finally, I'm sure you will take no comfort from the fact that none of the USAAF's or RAF's official P-51 speed performance results were ever quoted from NACA data.
Regards,
Brent Erickson
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This is about the D9 engine, right?
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Yeah but as usual LRRP2 got into his favourite agenda about that single stripped down Mustang, represenative of all.
Reminds me when Mike cried all over the place about that weirdo +25lbs Spit on the same graph.
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Lrrp says:
Please, quit being obtuse. You have been presented with hard data from an infinitely credible source that you refuse to accept, period.
Is the NACA not a credible source?
I fully accept the RAE report, LRRP2. It is you who refuses to acknowledge the NACA findings. If I jumped to bait everytime I came across one report...well, my book would say the FW-190 flew around with air to air guided missiles in the Geschwaders.
I just don't understand how you can ignore that FACT that the NACA concludes wartime performance testing of the P 51 was not representative of a frontline fighter.
All of the NACA's and North American's testing was designed to represent a frontline fighter at the time as well.
That is why it is called a "mistake".
Why don't you post the entire report instead of just piecemeal, BTW. It would make it easier to discuss. Having many PRO documents myself, I understand the expense and would gladly trade you a document of equal value.
All the best,
Crumpp
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Originally posted by Crumpp
I just don't understand how you can ignore that FACT that the NACA admits wartime performance testing of the P 51 was not representative a frontline fighter.
Could you please show where NACA did such statement.
gripen
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I would not mention favourite agendas Barbarrosa Isegrim with your 'penny pocket' 1.98ata 109 one.:rofl
Now, can we get back to the Dora, please.
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Gripen says:
Could you please show where NACA did such statement.
NACA says:
The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories.
\
All the best,
Crumpp
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Crumpp,
The statement you quote is not the opinion of the NACA about wartime performance testing.
The normally quoted performance numbers of the P-51 are not from NACA laboratories but from various testing organizations (Eglin field, A&AEE, Patuxent river, Wright field etc.) and tested planes were practically allways standard (mass produced) production planes.
gripen
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The normally quoted performance numbers of the P-51 are not from NACA laboratories but from various testing organizations (Eglin field, A&AEE, Patuxent river, Wright field etc.) and tested planes were practically allways standard (mass produced) production planes.
Come on Gripen.
Lets not split hairs. The NACA oversees the testing and fulfills a similar role as the RAE and RLM.
but it must be remembered that this was an advisory committee only, "to supervise and direct the scientific study of the problems of flight, with a view to their practical solutions." Once the NACA isolated a problem, its study and solution was generally done by a government agency or university laboratory, often on an ad hoc basis within limited funding.
http://www.hq.nasa.gov/office/pao/History/SP-4406/chap1.html
Many of the NACA's test's come from those government agencies you mention. Many of those agencies test's are the result of NACA discoveries.
The NACA had little to no stake in the P 51 Mustang and no reason to present a anything but the truth of the results they encountered.
All the best,
Crumpp
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Crumpp,
None of the quotes support your statement:
"the NACA admits wartime performance testing of the P 51 was not representative a frontline fighter."
Could you please show where NACA did such statement.
gripen
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NACA says:
The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories.
Meaning the manufacturers and end users where never able to achieve the standards of the NACA test's. As we saw in the P51 drag report, windtunnel and flight test's gave good agreement under test conditions. Problem is test conditions did not represent ground truth conditions.
NACA says:
For the best performance, manufacturing tolerances had to be perfect and maintenance of wing surfaces needed to be thorough.
Crumpp says:
"the NACA admits wartime performance testing of the P 51 was not representative a frontline fighter."
Is exactly what the NACA says above, Gripen.
All the best,
Crumpp
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Crumpp,
Performance numbers (from Eglin field, A&AEE, Wright field, Patuxent river etc.) for the Mustang are from the tests of (mass) production airfarmes and not from NACA laboratories. So the quote simply can't support your statement.
gripen
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Crumpp,
Again, none of the official performance numbers published for the Mustang (or any other service aircraft) were conducted by NACA or relied on NACA data. That was simply not its purpose. NACA conducted experimental and conceptual testing, not Army Air Force or Navy production performance trials.
The unavoidable fact is that all service performance numbers were generated by the services themselves, from stock production aircraft pulled at random from production batches. The USAAF and RAF had a critical interest in knowing what the production aircraft that they received from production batches were capable of. You have to understand that, don't you?
Does NASA perform service tests of the F-22? Of course not, the Air Force conducts its own test at Edwards Air Force Base just like the USAAF conducted its own tests at Wright Field or Eglin Field.
At this point, you're just being stubborn.
Originally posted by Crumpp
Meaning the manufacturers and end users where never able to achieve the standards of the NACA test's. As we saw in the P51 drag report, windtunnel and flight test's gave good agreement under test conditions. Problem is test conditions did not represent ground truth conditions.
I have no problem with that statement. Unfortunately, that statement has nothing to do with whether or not a P-51 in squadron service could exceed 430 MPH in level flight. The numbers published by the various services had nothing to do with NACA's experimental tests and everything to do with the Services' formalized evaluation process for production aircraft. NACA never performed production service performance tests. Please show me one instance of NACA performing level speed performance tests of a production P-51.
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Again, none of the official performance numbers published for the Mustang (or any other service aircraft) were conducted by NACA or relied on NACA data.
The NACA did not perform test's. It was an advisory committee that simply advised on others data.
but it must be remembered that this was an advisory committee only, "to supervise and direct the scientific study of the problems of flight, with a view to their practical solutions." Once the NACA isolated a problem, its study and solution was generally done by a government agency or university laboratory, often on an ad hoc basis within limited funding.
government agency
Are the following:
Gripen says:
various testing organizations (Eglin field, A&AEE, Patuxent river, Wright field etc.) and tested planes were practically allways standard (mass produced) production planes.
The standard (mass produced) production planes
were ones built by North American to their high standards as opposed by a subcontractor or the chaos of opening two huge new plants to meet the contract awarded from those test's.
All the best,
Crumpp
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Originally posted by Crumpp
The NACA did not perform test's. It was an advisory committee that simply advised on others data.
Are the following:
The
were ones built by North American to their high standards as opposed by a subcontractor or the chaos of opening two huge new plants to meet the contract awarded from those test's.
All the best,
Crumpp
Crumpp,
No USAAF or RAF P-51 Mustang was ever built by a subcontracter. Every one of the ~15,000 produced were produced by NAA at the Inglewood, CA or Dallas, TX plants. Fit and finish were always of extremely high quality. Considering the fact that the Mustang was produced in small numbers for nearly two years before the large Merlin Mustang contracts were awarded, it's not suprising that NAA had a pretty good handle on the production process by May of '43.
CAA in Australia license built some examples for the RAAF late in the war, but they never saw combat action.
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Every one of the ~15,000 produced were produced by NAA at the Inglewood, CA or Dallas, TX plants.
You are correct. However if you know the history of NAA then you know that huge additional plants were built to meet the demands of contract awarded to them by the USAAF.
Just as there are manufacturing differences between Focke Wulf Bremen and their plant in Sorau it is not unlikely that quality control issues arose for NAA during their expansion. Any plant manager for any manufacturering firm will confirm this fact of business.
To meet the demands of war, North American opened new factories in Kansas City, KS, and in Dallas, Texas.
http://www.boeing.com/history/bna/waryr.html
All the best,
Crumpp
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Crumpp,
You can't compare the production challenges faced by Focke Wulf to the production environment enjoyed by Noth American. They existed in two completely different worlds. The industrial production line utilized by NAA was far more conducive to uniform quality than were the more artisan- based systems used in Europe at that time. When you factor in forced (slave) labor, the differences become even more stark.
I have yet to see any reference to differences in production quality between the Inglewood and Dallas plants. Quite the contrary, in fact. Also, the Dallas plant was in operation well before Mustang production began there.
There were U.S. manufacturers that did have quality problems, Brewster being the most egregious while Curtiss had more than its share of quality issues as well. North American was certainly at the other end of that spectrum.
Originally posted by Crumpp
You are correct. However if you know the history of NAA then you know that huge additional plants were built to meet the demands of contract awarded to them by the USAAF.
Just as there are manufacturing differences between Focke Wulf Bremen and their plant in Sorau it is not unlikely that quality control issues arose for NAA during their expansion. Any plant manager for any manufacturering firm will confirm this fact of business.
http://www.boeing.com/history/bna/waryr.html
All the best,
Crumpp
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I have yet to see any reference to differences in production quality between the Inglewood and Dallas plants. Quite the contrary, in fact. Also, the Dallas plant was in operation well before Mustang production began there.
What your saying is extraordinary! I am sure then North American's management techniques are studied in every major business school.
Funny though I do not remember them being reviewed when I got my business degree.
I do remember:
http://www.michiganhistorymagazine.com/extra/willow_run/willow_run.html
However North American was never studied. Perhaps they should have been.
Unfortunately your claim is completely different from the NACA's facts on P 51 production standards.
All the best,
Crumpp
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Originally posted by Crumpp
What your saying is extraordinary! I am sure then North American's management techniques are studied in every major business school.
Funny though I do not remember them being reviewed when I got my business degree.
I do remember:
http://www.michiganhistorymagazine.com/extra/willow_run/willow_run.html
However North American was never studied. Perhaps they should have been.
Unfortunately your claim is completely different from the NACA's facts on P 51 production standards.
All the best,
Crumpp
I don't understand exactly where you are going with this. Are you claiming that NAA didn't have a well-developed assembly line system? What is so extraordinary about North American's production line? What is so hard for you to believe? Are you claiming that Focke Wulf's production realities were the same as NAA's? How many times was the Inglewood plant bombed? How many Mustang components were built in a cave? Are you denying the use of forced labor? Is this all based in an inability to accept that a typical P-51 produced in 1944-45 was of a much higher production quality than a typical Fw 190 produced during the same period?
As yet you have provided not a single shred of evidence to support your "NACA facts". All you've posted is a link to a general history webpage that states that it was impossible to achieve wind tunnel model tolerances on a 1940's production line. You'll get no argument there. It is your vast extrapolations of that statement and your total blindness to hard test data that is worthy of argument.
Let's clarify again- is it your position that USAAF and RAF service tested Mustangs were specially built models that achieved actual laminar flow in flight? Do you deny that the official performance numbers were based on representative production models of the same quality as those delivered to the squadrons? You must be. As long as you cling to the belief that official Mustang performance numbers were derived from NACA wind tunnels, further discussion seems pointless.
Why don't you just admit that you really want to believe that operational P-51's were all much slower than the offical figures. Staffeln Fw 190's on the other hand regularly met or exceeded factory spec's, didn't they?
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I don't understand exactly where you are going with this.
I am saying you are not considering the realities of business. Do a google search for "expansion management".
Your claiming North American pulled off a business miracle.
They rapidly and greatly expanded their company in order to meet the demands of the defense contract with no drop in production quality or output. No shortage of workers, in short no snags whatsoever.
They were already producing planes, sure. Where did they get the other skilled labour that fast to expand? I am sure that in 1942 skilled aircraft assembly workers were a dime a dozen and were just waiting to be hired with no training needed. Sign up and move to their spot on the line.
That is not even considering tooling, logistics, location concerns, etc....
Let's look at Willow run which also manufactered parts before it's expansion and is considered a model in manufacturing management:
The main building and the flying field were not completed until early 1942. But the plant, except for the relatively small area where parts production was underway, was in a state of turmoil as tools were received, fixtures set up and supervisors and untrained employees tried coping with an alien undertaking. The task was aggravated by a severe housing shortage near the Willow Run vicinity and the length of time required—an hour or more each way—for Detroit workers to commute to and from their jobs.
The myth that Willow Run was performing production miracles exploded in August 1942 when James H. "Dutch" Kindelberger, the blunt president of North American Aviation, told a startled group of reporters that Willow Run, despite all of the talk, had yet to manufacture an airplane.
In January 1943 the government’s War Production Board officially criticized Willow Run’s performance for the first time. The factory’s primary problem, according to the board, was a shortage of manpower, the plant found it difficult to hire and keep competent workers.
During the last few months of 1943, as the giant plant began living up to its press notices of 1941 and the first half of 1942, the threat of a government takeover faded.
The total number of B-24s built at Willow Run was 8,685. The last bomber, named the "Henry Ford," moved off the assembly line on June 24, 1945. A few minutes before the plane was to be towed from the plant, Henry Ford requested that his name be removed from the nose of the ship and that employees sign their names in its place.
Willow Run was a miracle plant, but Henry Ford was not a miracle man, and the wartime belief that he was is one of the great myths of World War II.
http://www.michiganhistorymagazine.com/extra/willow_run/willow_run.html
http://www.liberatorcrew.com/06_B-24_Prod.htm
The Focke Wulf Sorau anecdote was used simply to show that even among the same manufacturer there are quality differences and not as you try to make it out to be, a cry of superiority.
Don't believe the same manufacturer can have quality differences, buy any car made on a Friday or a Monday!
As long as you cling to the belief that official Mustang performance numbers were derived from NACA wind tunnels, further discussion seems pointless.
Where do you see wind tunnels only in this? Are you missing the "test flight" portion followed by "good agreement"?
In order to obtain a correlation of drag data from wind-tunnel and flight tests at high Mach numbers, a typical pursuit airplane, with the propeller removed, was tested in flight at Mach numbers up to 0.755, and the results were compared with wind-tunnel tests of a 1/3-scale model of the airplane. The tests results show that the drag characteristics of the test airplane from tests in the Ames 16-foot high-speed wind tunnel of the Ames Aeronautical Laboratory can be predicted with satisfactory accuracy at both high and low Mach numbers. It is considered that this result is not unique with the airplane.
http://naca.larc.nasa.gov/reports/1948/naca-report-916/
However the NACA concluded that frontline units would not see the same results due to:
NACA says:
The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories.
NACA says:
For the best performance, manufacturing tolerances had to be perfect and maintenance of wing surfaces needed to be thorough.
http://www.hq.nasa.gov/office/pao/History/SP-4406/chap2.html
You can slice it up anyway you want but the facts are the facts.
As yet you have provided not a single shred of evidence to support your "NACA facts".
What are your standards? That I go back and reproduce all the test's and reports from labs, government flight test's, and combat unit reports that led the NACA to this conclusion?
Why?
It's not Crumpp's conclusion, it's the NACA's from their own website!
Besides you have your one report to refute all the NACA's work and conclusions.
All the best,
Crumpp
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Crumpp,
You've posted those links over and over, yet neither provide any support to your claim that Speed performance numbers published by the USAAF and RAF were not attainable by typical production examples or airfrmes in squadron service. None.
The first says that the production lines of the time couldn't provide the necessary finish tolerances to allow for true laminar flow. Big deal- no P-51 Mustang that took to the air ever attained actual laminar flow.
The drag report says that under extremely controlled conditions, a stripped, hand polished and unpowered P-51B could closely mimic the bahavior of wind tunnel models. Even in the wind tunnel, incomplete laminar flow was only achievable for brief periods.
In application, the laminar flow airfoil was used during World War II in the design of the wings for the North American P-51 Mustang, as well as some other aircraft. Operationally, the wing did not enhance performance as dramatically as tunnel tests suggested. For the best performance, manufacturing tolerances had to be perfect and maintenance of wing surfaces needed to be thorough. The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories. Still, the work on the laminar flow wing pointed the way to a new family of successful high-speed airfoils. These and other NACA wing sections became the patterns for aircraft around the world.
Your favorite passage only says that a true laminar flow wing was not possible during WWII. It wasn't present in squadron service and it wasn't present during Service Performance Trials. When Mustang III FX953 reached 450 mph at 28,000 ft during the A&AEE Level Speed Performance tests (AVIA 18/732, Boscombe Down, March, '44), it did so without the benefits of laminar flow. The same applies to P-51B-15-NA 43-24777's 426 mph at 23,800 ft (ENG-57-531-306, Wright Field. May '44). Both are flight-tested production airplanes, neither of which required "perfect" production tolerances to achieve the listed speeds. How about the Eglin P-51B test- 435 mph at 27,000 ft, with wing racks. Again, a production model tested after delivery to the USAAF.
Why didn't these (and other) tested production examples require perfect wing surfaces to achieve these speeds? Because the Mustang' speed performance was based on an excellent cooling drag recovery design and a generally slick shape. Its high quality (not perfect) production standards didn't hurt either. The primary benefit of the laminar profile wing was its ability to delay the onset of compressibility at high speeds. In all actuality, the Spitfire's thinner wing was probably slightly more aerodynamically efficient than the Mustang's laminar profile. Did puttying and sealing the Mustang's wing help? Of course it did, but it helped any aircraft so treated.
I'm sure you'll repost your two links to 'refute' me again. Oh well, have at it...
.
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LRRP2,
What you seem to be missing is that is a post-war conclusion.
Don't you wonder why the question even came up or are you blinded by your in game desires?
Have we made any progress or do you still believe North American pulled off a manufacturing miracle that should be studied and modeled in modern business programs?
During the war and during testing of the Mustang the NACA conclusions were:
In order to obtain a correlation of drag data from wind-tunnel and flight tests at high Mach numbers, a typical pursuit airplane, with the propeller removed, was tested in flight at Mach numbers up to 0.755, and the results were compared with wind-tunnel tests of a 1/3-scale model of the airplane. The tests results show that the drag characteristics of the test airplane from tests in the Ames 16-foot high-speed wind tunnel of the Ames Aeronautical Laboratory can be predicted with satisfactory accuracy at both high and low Mach numbers. It is considered that this result is not unique with the airplane.
Windtunnel and flight test's gave good agreement!
After the war it was concluded:
The rush of mass production during the war and the tasks of meticulous maintenance in combat zones never met the standards of NACA laboratories.
I imagine it came up due to complaints like the report I saw in the archives of the 8th AF.
The resulting investigation most likely concluded the only thing to be done was as the NACA says:
For the best performance, manufacturing tolerances had to be perfect and maintenance of wing surfaces needed to be thorough.
LRRP2 says,
I'm sure you'll repost your two links to 'refute' me again. Oh well, have at it...
It's not me that is refuting you, you are refuting the conclusions of the NACA.
All the best,
Crumpp
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Dang......you two are like women arguing over whose dress is the nicest and bestest based on how much they paid for it.....:rolleyes:
All that aside.....far as I know, no NACA squadron was deployed, no NACA member shot down an enemy AC, so I would tend to believe reports from the field. In short, NACA opinions mean diddly squat. Not worth the paper they were written on.
NACA, from what has been posted here, were nothing more than government bean counters, putting out paper reports to make themselves feel important.
Bottom line is, did the plane(s) get the job done?
In the case of the Mustang, the answer is a resounding YES. Must have sucked to be a LW big wig and find out you got your butt shot off by an enemy aircraft that wasn't performing to it's potential. Kinda makes the ego go a little flat, no?
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Originally posted by LRRP22
Is this all based in an inability to accept that a typical P-51 produced in 1944-45 was of a much higher production quality than a typical Fw 190 produced during the same period?
I`d like to see evidence to that.... 'fact' as you call it.
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Originally posted by Crumpp
It's not me that is refuting you, you are refuting the conclusions of the NACA.
All the best,
Crumpp [/B]
No Crumpp, I'm not refuting NACA. I don't need to, NACA hasn't said anything of real relevance to this argument. The USAAF, RAF and even U.S. Navy are refuting your assertion that production P-51's were somewhow hamstrung.
Whether the NACA conclusions were arrived at during the war or after the war; whether the 1/3 scale model agreed with the towed P-51B dive test is irrelevant. Neither of the conclusions in any way invalidate the numbers generated by numerous service flight tests which, for your claims to be true, they must!
If the wind tunnel was able to accurately predict performance, then if youFX593 was tested in the wind tunnel, the wind tunnel would have predicted that it was capable of 450 mph at 28,000 ft. Do you agree?
You've just spent thousands of words telling us that production P-51's were not capable of wind tunnel performance. Well, what was the wind tunnel performance- you have no idea. For all you, or anybody, knows a perfect wind tunnel shape may have predicted 480 mph for the Merlin Mustang.
It's time for you to fish or cut bait- Are you claiming that the USAAF and RAF tests of production aircraft are wrong? Please don't give a cryptic, lawyerly response like "It is my contention that the NACA was correct in its conclusions:"- just answer the question, yes or no.
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Originally posted by Kurfürst
I`d like to see evidence to that.... 'fact' as you call it.
Strategic Bombing Campaign, forced and slave labor, dispersed manufacture, collapsing infrastructure, material quality problems and shortages....
Only in your world was the German aircraft industry producing top quality products in 1945.
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Only in your world was the German aircraft industry producing top quality products in 1945.
It's interesting that comments on the high quality of aircraft coming from Sorau occurred in late 44 early 45 and where made about an FW-190D9.
Manufacturing dispersion does not mean poor quality. Ask any modern car manufacturer.
I think you should do some more research. While quality control issues were always a concern the idea that production standards evaporated is a false one.
All the best,
Crumpp
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Originally posted by LRRP22
Strategic Bombing Campaign, forced and slave labor, dispersed manufacture, collapsing infrastructure, material quality problems and shortages....
In other words, only naive assumptions that everything in Germany was bad, everything in Alliedland was perfect. Thank you for clarifying.
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Originally posted by Kurfürst
In other words, only naive assumptions that everything in Germany was bad, everything in Alliedland was perfect. Thank you for clarifying.
No Isergrim, obviously everything was just swell in 1945 Germany...:rolleyes:
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Originally posted by Crumpp
It's interesting that comments on the high quality of aircraft coming from Sorau occurred in late 44 early 45 and where made about an FW-190D9.
Manufacturing dispersion does not mean poor quality. Ask any modern car manufacturer.
I think you should do some more research. While quality control issues were always a concern the idea that production standards evaporated is a false one.
All the best,
Crumpp
Just asking as I don't know, but what was the process for accepting an aircraft by the LW in 1945?
Were they still doing like the RAF and USAAF where each aircraft was test flown and had to meet certain performance expectations? Did they have service test pilots still flying each aircraft before delivery on these flights etc?
I would think that by that time with the pilot shortages the LW was facing that any experienced pilots would have been flying combat if possible.
I've understood it from comments made about the 262 for example that there were shortcuts being taken when it came to strategic metals in the airframe and engine builds.
As mentioned all was not perfect in US production with P47Gs from Curtiss not being up to standards as an example. Brewster built Corsairs another example of poor quality workmenship.
That being said, the aircraft that reached the squadrons were not those birds, but ones that has passed all acceptance tests.
I note mention of Mustangs. One of the things done with 51s even the natural metal birds, was that the wing was actually filled, smoothed, primed and painted silver to keep the airflow over the wing smooth.
I have no idea what that process was for the LW by 1945 in production testing and acceptance.
Dan/CorkyJr
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Certainly there were accaptance flights for each and every aircraft - JaPo 109K has the acceptance flight date for many Werknummers. BAL was responsible for the quality control, but I am not sure what the process was.
On the sidenote, I`ve talked to a hungarian factory test pilot, he said something about checking the airspeeds but we did not get into details.
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Were they still doing like the RAF and USAAF where each aircraft was test flown and had to meet certain performance expectations? Did they have service test pilots still flying each aircraft before delivery on these flights etc?
Hey Guppy!
You asked to me describe something that is hardly typical. There was no "one way" things were done and each company had it's own policy.
As I understand Focke Wulf policy was each aircraft was inspected and flown.
Kurt Tank did an excellent job engineering the Focke Wulf to be maintenance and production friendly. You can literally strip the entire cockpit in only a few minutes. Remove the seat, left/right console, upper/lower instrument panel leaving nothing but the empty fuselage. No tools required.
Subcontractors would build aircraft subcomponents. Included in this are many subcontractors whose factories were located in neutral countries.
For example, one company might build a wing, while another assembles the cockpit Geratbank and so on and so forth.
These would be shipped to final assembly points, inspected upon arrival, and then they would be assembled into the complete aircraft. Many of these were underground as in the Berlin Airport.
Inspections were of course done at all stages as standard practice. Just as in most aircraft manufacturers.
Once assembled, the aircraft would be either be shipped by rail or enter their final stage right there at the factory.
The final stage was either Focke Wulf company pilots or Luftwaffe pilots flew the aircraft to their final destination. Sometimes this was the Geschwader but in other cases it was a Luftwaffe depot where it received final inspection and became Luftwaffe property.
Certain subcontractor's manufactured complete FW-190's and oversaw their web of subcontractors. Focke Wulf maintained oversight with these contractors.
These flights included a checklist of function tests. I don't think they "put the aircraft through its paces" though. New engines require a break in period so unless the allied companies were only releasing aircraft after they passed the minimum hours required for break in I find it hard to believe they were putting aircraft through full top performance test's either.
I wonder if USA transatlantic ferry flights had time to break the aircraft in?
I will dig out some pictures I have of Focke Wulf, Sorau's factory production quality control example. This aircraft was flown to various subcontractors such as Arado, Dornier, and many others who built FW-190's as an example. With it came a team of Focke Wulf company employees who would inspect the factory and train personnel to meet company standards.
Now this system did start feeling strain in 1945. It did maintain and was in place though up until the last few weeks of the war.
All the best,
Crumpp
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Hi Guppy,
>Just asking as I don't know, but what was the process for accepting an aircraft by the LW in 1945?
>Were they still doing like the RAF and USAAF where each aircraft was test flown and had to meet certain performance expectations?
Yes. It's documented in the case of the Me 262. However, the case of the Me 109K shows that a lot of defects (some of them actually caused by sabotage) escaped the acceptance pilots and had to be fixed by the front-line units. (These defects weren't necessarily performance-related, though.)
>I've understood it from comments made about the 262 for example that there were shortcuts being taken when it came to strategic metals in the airframe and engine builds.
Hm, it seems to be only the engines that were effected, but the impact was decisive. The Jumo 004A would have been ready for production 12 months ahead of the Jumo 004B, which had to make do without strategic resources.
>As mentioned all was not perfect in US production with P47Gs from Curtiss not being up to standards as an example. Brewster built Corsairs another example of poor quality workmenship.
Another would be the Boeing B-29 - I believe there's a story about the so-called "Battle of Kansas" that was "fought" in order to make the factory-fresh Super Fortresses combat-ready by fixing a great number of defects. "Rosie the Riveter" and her colleagues were not skilled factory workers with years of experience.
But without such quickly trained workers, the enormous expansion of the relatively modest US American pre-war aviation industry would of course have been impossible.
The German industry failed to expand like that, and the Luftwaffe ended up with a certain shortage of aircraft as a result. It was only Speer who exploited the full industrial potential - probably backed by Goebbels "Total War" propaganda, which was really aimed at the "home front" if I understand that correctly.
>I have no idea what that process was for the LW by 1945 in production testing and acceptance.
I'm sure it went downhill as the war progressed. That probably placed the burden of making sure the aircraft were combat-ready with the service units. From a quality management point of view, that's rather inefficient of course.
(By the way, late in the war the production methods were simplified wherever possible - this process was called "Entfeinerung" = 'de-sophistication'. An Orwellian term for sure :-)
Regards,
Henning (HoHun)
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Think I posted it before but the image is a scan of a Spitfire production test card that I got from a B of B vet, later production test pilot at Supermarine.
Not real complicated but clearly they were making sure things worked :)
Dan/CorkyJr
(http://www.onpoi.net/ah/pics/users/810_1118880708_spittestcard.jpg)
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Not real complicated but clearly they were making sure things worked
It's about the same. I have several reports investigating sabotage. Focke Wulf implemented additional inspections to prevent or catch it before the aircraft left the factory. Nothing performance related, just preventive maintenance service checks.
All the best,
Crumpp
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FW used similar forms.
I have found a couple of them in munich, for the FW190A3 & A5. They had three columns, first one with the demanded values and the other two where the values from the two check flights were to be inserted.
The flights required only tests at Climb & Combat power, but i guess that was to prevent overstrain on a fresh engine.
Interesting to note that the inspection pilots were also ordered to test the control forces and if they were inside the limits.
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Interesting to note that the inspection pilots were also ordered to test the control forces and if they were inside the limits.
Exactly!
Even the Luftwaffe had a hard time keeping the ailerons adjusted on the FW-190. It is a reoccurring theme throughout FW-190 service.
The first sign of improperly adjusted control surfaces in the FW-190 was the stick forces increasing above a few kilograms.
All the best,
Crumpp
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:cool: man crumpp u and LRRP22 really had a go at it didnt ya hehe =]
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0utbr3ak
708th Bomber Group
(http://www.imagehostwiz.com/uploads/bgsquadsigob.jpg)
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Originally posted by gripen
The 006 is so much slower than others that it is possible that it actually did run at lower MAP than the 002 and 043. That also explains higher FTH.
The test report confirms this; at 3000rpm the MAP at FTH was about 1,52 ata in the case of the 006 (with series engine) while in the other cases (001, 002, 003...) the MAP at FTH was about 1,57-1,6 ata. Above FTH there appear to be not much difference in the supercharger performance of the tested engines. Anyway, the actuall output of the engines did vary quite bit (when different engines were tested in the same airframe).
gripen