Spit vs. Messer : Design vs. Design

[Angus]

Nice Crumpp

I'll try and break this into numbers. It will be an error of maybe 2-3 mph if I do good.

You know, still working on graphs....


BTW, where can I get pictures hosted? The picture hangar is closed.

[LRRP22]

Crummp's quote:
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Notice the speed gains occur after the wing is cleaned up AND the racks removed.

The question becomes in 1944 just how many P51B's were flying in a clean configuration without the wing drop tanks into German Controlled airspace.
----------------------


From AVIA 8/10618:

"...the seperate items are estimated as 8 mph due to the bomb racks...and 12 mph due to improved finish."


That puts FB377 at 395 mph/636 kph at SL in full combat configuration with bomb racks.  By September of '44 the RAF had 250 Mustangs ranging over NW Europe in this configuration, and 350 by Mar/April '45.  At any given time during that period they were as common, or more common, than Fw 190D-9's.

All of the charts you posted are for early P-51B-1-NA's equipped with the higher-rated V-1650-3 running at +18 lbs/67" Hg WEP.  This configuration represents the slowest of all Merlin Mustangs at low altitude.  The V-1650-3 at +18 lbs boost developed 400 hp less than a V-1650-7 running at +25 lbs boost.   By September '44, all RAF Merlin Mustangs (all Mustang III/P-51B/C's) in the ETO were running +25 lbs boost. It is 250 hp less than USAAF P-51B/C/D/K's running at their standard +21 lbs/72" Hg boost.

It is entirely possible that Oscar outran some USAAF P-51D's on the deck- it is also quite possible that they weren't running at full WEP, either.  After all, chasing a single 190 may not be reason enough to firewall the throttle and run at max boost for a long period of time over enemy territory.  Being chased  by a 190 on the deck most certainly would be.  What is not possible is that he could have outrun a 2000+ HP RAF Mustang III at any altitude.  edit: Let me clarify that statement- Of course it is possible that a new condition 190A9 could outrun a +25 lbs clapped-out Mustang III with a rough airframe and a tired engine.  However, if both airplanes were in similar condition the Mustang III would be much faster at most altitudes.

Maybe you should overlay a BMW 801TS-equipped 190A8/A9's speeds against this chart, especially that red line to the far right:

[Crumpp]

That puts FB377 at 395 mph/636 kph at SL in full combat configuration with bomb racks. By September of '44 the RAF had 250 Mustangs ranging over NW Europe in this configuration, and 350 by Mar/April '45. At any given time during that period they were as common, or more common, than Fw 190D-9's.

In September of 1944 the FW-190A9 was well on the scene and the FW-190A8 engine upgrade was in place.  Your chances of encountering an 801S equipped FW-190A were just as great as your chances of encountering a (+25) Mustang III.

Dora's were in factory trials in September and not operational trials.

In March/April '45 the FW-190D9 was the most common FW-190 fighter in the JG's.  

 

It is entirely possible that Oscar outran some USAAF P-51D's on the deck- it is also quite possible that they weren't running at full WEP, either. After all, chasing a single 190 may not be reason enough to firewall the throttle and run at max boost for a long period of time over enemy territory. Being chased by a 190 on the deck most certainly would be. What is not possible is that he could have outrun a 2000+ HP RAF Mustang III at any altitude. edit: Let me clarify that statement- Of course it is possible that a new condition 190A9 could outrun a +25 lbs clapped-out Mustang III with a rough airframe and a tired engine. However, if both airplanes were in similar condition the Mustang III would be much faster at most altitudes.

Is it possible the P51D's chased him after bouncing his Staffel on it's way to support the Heer in the Ardennes offensive on reduced power, sure.  Is it likely?  Most certainly not.

 As Oscar told the story to me on two separate occasions:

Oscar had just turned with and shot down 1 P51D that had overshot the initial bounce and was forced to turn defensively.  When he checked six, he counted five others in the turning circle.  He rolled out, dove, hit boost and ran at tree top level to escape.  As he leveled out he checked six again still seeing 5 P51D's.  After a protracted chase he began to outdistance them.  The Mustang's gave up and turned for home.

Again it was P51D not a P51B or a Mustang III.

Many pilots regarded the Malcolm-hooded P-51B/C as the best Mustang of the entire series. It was lighter, faster, and had crisper handling than the later bubble-hooded P-51D and actually had a better all-round view. Its primary weakness, however, was in its armament--only four rather than six guns, which often proved prone to jamming. Some of the modifications applied to the P-51D to improve the ammunition feed were later retrofitted into P-51B/Cs, which made them less prone to jamming. With modified guns and a Malcolm hood, the P-51B/C was arguably a better fighter than the P-51D, with better visibility, lower weight, and without the structural problems which afflicted the D. Its departure characteristics were also more benign.

http://home.att.net/~jbaugher1/p51_9.html

Crumpp

[LRRP22]

Crummp,

Oscar's account sounds about right for an encounter between an Fw 190A-9 (or re-engined A-8) and USAAF P-51D's running 72" Hg WEP- i.e., very close at lower altitudes.  

Considering the time frame, it is also very possible that those Mustangs were from 8th AAF's forward-deployed  (Belgium)  352nd or 361st FG's.  Both groups were almost certainly limited to 67"/+18 lbs boost due to the lack of 100/150 grade fuel at the 9th AAF bases to which they were assigned.  2nd TAF converted to 100/150 grade in late '44 while 9th AAF apparently did not.

Remember, I wasn't contesting Oscar's account- I posted in response to your comment that an 801S-engined 190 would be slightly faster than an RAF Mustang III running +25 lbs boost.  That is not at all true.

BTW, Oscar who?

--------------------------------------------
Is it possible the P51D's chased him after bouncing his Staffel on it's way to support the Heer in the Ardennes offensive on reduced power, sure. Is it likely? Most certainly not.

As Oscar told the story to me on two separate occasions:

Oscar had just turned with and shot down 1 P51D that had overshot the initial bounce and was forced to turn defensively. When he checked six, he counted five others in the turning circle. He rolled out, dove, hit boost and ran at tree top level to escape. As he leveled out he checked six again still seeing 5 P51D's. After a protracted chase he began to outdistance them. The Mustang's gave up and turned for home.

Again it was P51D not a P51B or a Mustang III.
--------------------------------------------:)

[MiloMorai]

LRRP,

did the P-51 have overheating problems when operating at high boost? The other question is, how long could the P-51 run at max speed? Thanks


Crumpp, nice to see you back.

I know you posted some times the 190 at 1.42 and higher boost. Could you refresh my memory? Thanks.

[Crumpp]

Remember, I wasn't contesting Oscar's account- I posted in response to your comment that an 801S-engined 190 would be slightly faster than an RAF Mustang III running +25 lbs boost. That is not at all true.

That is not what I claimed.  Please read the post's.  I said that Oscar's account is entirely possible according to the documentation.  Although Oscar does not know the exact varient of engine in his FW-190A8 that day the varient of 190 he flew had priority to recieve the engine upgrade.  The only way he could have outran those Mustangs was with an 801S equipped aircraft.  

The documentation trail gets thin on late war technical development of Luftwaffe aircraft.  Several years ago many would claim the FW-190A9 never saw combat or was a very rare varient.  We now know that the FW-190A9 was much more common and saw service much earlier than previously thought.  By Luftwaffe documentation there were well over 1000 FW190 varients equipped in production with the 801S motor.  Additionally the Luftwaffe enacted an engine replacement program in July '44 and the BMW801D2Q was a direct swap for the 801S.

Once you realize the shortcomings of the BMW801D and the very simple technical upgrades that corrected these in the 801S, it is easy to see that this was a very easy program to enact.  This is backed up by physical evidence, pilot anecdotes, and documentation.

Oscar Boesch

http://www.riveting-images.com/Robert_Bailey_s_Aviation_Art/Robert_Bailey_s__War_Wolf_/robert_bailey_s__war_wolf_.html

Thanks Milo!

The longest times I have documentation for any of the FW-190A's at 1.42ata@2700U/min is 3 minutes.  Pilot anecdotes say this time was increased in the FW-190A8 and later series begining in mid 1944 to 20, 30, and finally 40 minutes.  However I have seen no documentation to back this up.


Crumpp

[Kurfürst]

Originally posted by LRRP22

As for TK589, I don't dispute the speeds- I just don't believe that it represents the speed of a factory fresh airframe.

and

 the description of the wing surfaces was, as you know, a factory finish.  All Mustangs had filled and sanded wing joints- every single one.

[/B]

So TK 589 with a condition of factory finish was not representative for a plane with factory finish condition.
OK.

Originally posted by LRRP22

Like I said,  the +18 lbs speeds only seem to be 5-10 mph below other tests which could easily be attributed to a little engine wear and tear.

[/B]

"Other tests"? What other tests?
Oh, the ones that supposed exist and supposed prove the supposed 5-10 "too slow" claaim. Got it know.

[Kurfürst]

Originally posted by LRRP22
Crummp's quote:
Notice the speed gains occur after the wing is cleaned up AND the racks removed.

Notice that one of the is a cleaner P-51B, the other is a draggier P-51D...

Oh, unimportant, blending it together until it fits the agenda is nice enough.

[LRRP22]

LRRP,

did the P-51 have overheating problems when operating at high boost? The other question is, how long could the P-51 run at max speed? Thanks

Milo,

Not that I am aware of.  WEP was always limited to 5 minutes in both the Spitfire and Merlin Mustang, regardless of boost level, but that was intended to extend engine life and not because of  engine cooling or failure problems.

Here is an explanation from the P-51's flight manual:

'It is often asked what the consequences will be if the 5-minute limit at Take-off Power is exceeded. Another frequent inquiry is how long a period must be allowed after the specified time limit has elapsed until Take-off Power can be used. These questions are difficult to answer, since the time limit specified does not mean that engine damage will occur if the limit is exceeded. Instead, the limit means that the total operating time at high power should be kept to a reasonable minimum in the interest of prolonging engine life.

Nevertheless, it is still the aim of the manufacturer and to the best interest of the pilot to keep within reasonable values the amount of high-power time accumulated in the field. The most satisfactory method for accomplishing this is to establish time limits that will keep pilots constantly aware of the desire to hold high-power periods to the shortest period that the flight plan will allow, so that the total accumulated time and resulting wear can be kept to a minimum. How the time at high power is accumulated is of secondary importance; i.e., it is no worse from the standpoint of engine wear to operate at Take-off Power for one hour straight than it is to operate in twelve 5-minute stretches, provided engine temperatures and pressures are within limits. In fact, the former procedure may even be preferable, as it eliminates temperature cycles which also promote engine wear. Thus if flight conditions occasionally require exceeding time limits, this should not cause concern so long as constant effort is made to keep the over-all time at Take-off Power to the minimum practicable.'

[Kurfürst]

Originally posted by Angus
So,,,,,old second hand Spitties were not on pair with the newest German and even Russian stuff, and non original radio sets were not too good.

Yes Angus, the "old second hand etc." Spitfire Vs, which formed the bulkhead of the RAF at that time in 1943 also, did not fare well against the newest German/Russian stuff, already dominant in service. And the Russians weren`t amused by it - unlike with the 109.

[Kurfürst]

Originally posted by LRRP22
Milo,

Not that I am aware of.  WEP was always limited to 5 minutes in both the Spitfire and Merlin Mustang, regardless of boost level, but that was intended to extend engine life and not because of  engine cooling or failure problems.

[/B]

Yet, by coincidence, the time limit imposed on the Merlin 66`s operating temperature was max. 5 limits at 135 degrees temperature. I believe the V-1650-7`s was somewhat lower.

[LRRP22]

From Isegrim:

Notice that one of the is a cleaner P-51B, the other is a draggier P-51D...

Oh, unimportant, blending it together until it fits the agenda is nice enough.

Isegrim,

You love to harp on this suppossed large speed difference between the P-51B and P-51D.  

The fact is that when comparing V-1650-7 engined P-51B/C's to P-51D's, all NAA and USAAF tests of new production airframes show that the difference in speed amounted to a grand total of 2-3 mph at all altitudes.  The P-51D was approximately 10 mph faster than the V-1650-3 P-51B at low altitude.

Everyone must realize that to Isegrim/Kurfrurst, Spifire LF IX JL165 and P-51D TK589 represent the end-all and be-all of performance for those two types.  His reason for this becomes obvious when you also realize that JL165 and TK589, both well-used testing establishment airframes, generated the lowest perfomance numbers of all available data for those two aircraft types.  He summarily dismisses data from any other tests since those results are inevitably better  than those derived from tests conducted with those two airframes.

Isegrim commenting on 'Agendas' is truly the height of irony...

[LRRP22]

Yet, by coincidence, the time limit imposed on the Merlin 66`s operating temperature was max. 5 limits at 135 degrees temperature. I believe the V-1650-7`s was somewhat lower.

You 'believe' a lot of things, Isegrim- most of which are not supported by the facts.

Apparently (thanks hop2002), RAF Merlin 66 Spitfire cooling tests showed that it would take approx. 46 minutes at +25 lbs boost for the the Merlin 66's coolant temperature to rise from the 89 deg. C cruise temperature, to the 135 deg C maximum.   So much for 5 minutes...

I would love to know why you believe (there's that word again) the V-1650-7's limit was somewhat lower than the 66's.

[LRRP22]

So TK 589 with a condition of factory finish was not representative for a plane with factory finish condition.

Isegrim,

Factory fresh "finish" and "factory fresh" are two entirely diffrerent things.  By the time your test was conducted, TK589 had been in the hands of the RAF testing establishment for six months.  It may well have maintained a near factory surface finish, but the chances are that its engine was anything but 'factory fresh'.

[Kurfürst]

Several P-51 speed tests, originally researched by Neil Stirling :

P51B performance figures using 150 grade fuel and 75"hg.


Airplane P51B 43-24777, V-1650-7, 9680lbs Wing racks fitted.
Date 4,30,44.
Test results and again appprox as the figures come directly from the curve in front of me.

379mph at 0ft
410mph at 7,400ft
405mph at 13,100ft
431mph at 20,500ft
420mph at 28,000ft
416mph at 30,000ft


Avia 18/732.

AAEE Boscombe Down.
Mustang IV T.K 589 (Packard MerlinV.1650-7)
Posistion error of static vent and brief level speed trials.
July 1944.
Aircraft flown with faired bomb racks.

Speed at 0 ft using 67"hg 354mph
Speed at 10300ft using 67"hg 396mph
Speed at 0ft using 81"hg 379mph
Speed at 4300ft using 81"hg 398mph.


AVIA 6/10618

August 1944

Mustang III FB 377
Wing racks fitted. +25Lbs boost

383mph at 0ft 391mph at 3900ft.


INTER-OFFICE MEMORANDOM.

Army Air Force
Material Command
ENG-57-531-306
13 May 1044.

Performance tests on P38J,P47D and P51B airplanes tested with 44-1 fuel (150 grade)

P51B 43-24777
Wing racks fitted.

61"hg 352mph at 0ft, 405mph at 13100ft, 422mph at 26600ft
67"hg 364mph at 0ft, 408mph at 10400ft, 426mph at 23800ft.
75"hg 380mph at 0ft, 410mph at 7200ft, 431mph at 20500ft.



This is from another source :


CFE: Mustang III with V1650-7 engine, Military Power (61"/3000R)
     Test Weight: 9200#
     Vmax: 438 mph @ 27500'
    412 moh @ 14000'


Eglin: P-51B with V1650-3 engine, Emergency Power (67"/3000R)
     Test Weight: 9690# (Pylons attached)
     Vmax: 435 mph @ 27000'
    420 mph @ 13100'

EE 393: P-51B with V1650-3 engine, Emergency Power
     Test Weight 9200#
     Vmax: 450 mph @ 28200'
    430 mph @ 15300'


Pax River:  P-51C with V1650-3 engine, Emergency Power
     Test Weight 9423#
     Vmax: 450 mph @ 29200'
    426 moh @ 15600'


This is also interesting :

"The printed maximum speed in all books for the NA P-51D Mustang is 437 mph at 25,000 ft. The fastest speed ever actually RECORDED for a P-51D ocurred on 20 October 1944, over Henden RAF base, England.
Following RAF complaints that the P-51 would not reach the printed speeds, no fewer than 12 Mustangs from various units--two right off the boat, as well--were tested with USAAF pilots. Both theodolite units and radar were used to measure the speed. The fastest run - I should mention after innumerable flights occupying the whole day - was 416 mph in a P-51B (s/n 36799 "Carolina Hustler"); this speed was sustained only for 10 seconds before the engine became seriously over-boosted. The longest sustained maximum speed recorded was 405 mph for 55 seconds by a brand new P-51D at 23,000 ft. (s/n 472484). Most of the machines in this evaluation were incapable of exceeding 400 mph under any conditions whatever. The NII VVS tested their P-51B (L-L, s/n 35145) to a maximum of 392 mph at 25,500ft, and climb to 5000m of 6.5 mins. Tests done on 100 octane gas."



LRRP2, you can fluff your baloon, go into longht depths about the 'poor' nature of ALL the aircraft used in ALL tests... you can add Hop`s own brainchild - kindly show a qoute from the report you claim states 45 mins... you can go into lenght about my person and my 'agenda'..and so on.

All this only shows you have no facts, just the desperation so that your hand-picked test will be the last and only world in the subject. And for the lack of factuality, you make up with talk, talk, talk.
I am sure the retarded ones will buy it all. More serious people will take their bet on the RESULTs.