Bf 109 G range and endurance

[phookat]

Originally posted by VO101_Isegrim
BRIEF PERFORMANCE TRIALS OF SPITFIRE MK VIII AIRCRAFT
FUEL CONSUMPTION TRIALS

Apperantly, Nashwan`s 10 mph claim is only from a quick and rough testing with possibly not even the right equipment available for correct measurments, being hastily done with large margin of error.

Perhaps it was brief, but it doesn't look to me like there is any particular reason to suspect this report of having greater margins of error, than other tests.

Originally posted by VO101_Isegrim
Still, the official British words is that the Mk VIII`s range is 740 miles on 120 gallons internal fuel.

I don't think Nashwan's report conflicts with this, necessarily.  That 10 mpg figure is for a *very* low speed (160 mph indicated).  The official range figures are probably for a higher test speed.

But even considering Nashwan's data, the 109G is definitely more fuel efficient than the Spit 8 (see the 210 mph row in the Spit charts).

[VO101_Isegrim]

Originally posted by Nashwan

You don't want to accept that figure, so you have posted various documents, none of them tests, none of them giving exact conditions, many of them not even stating what engine.

[/B]

Actually, all of them stating what engine is used and what are the cruising speeds they refer to.

"Every single book states the Spitfire had 430-450 miles on internal on 85 gallon. "

I could ask with which engine, but instead I'll use one of your own quotes, from the very first post in this thread:

Well, one is for Merlin 61, and says 450 miles. the other is for Merlin 266, ie. US-built 266, and says 434 miles.

But what about Spitfire the History, I know this is the most accurate book on the Spit, what range does it give for the Mk IX and VIII ?

What about posting the complete report you've extracted the 109 range figures from?  Can we see it all, please? [/B]

It`s several megabytes long, so I won`t upload it into a site. But drop me an email at executor@index.hu and I will send it forward.

[Nashwan]

I don't think Nashwan's report conflicts with this, necessarily. That 10 mpg figure is for a *very* low speed (160 mph indicated). The official range figures are probably for a higher test speed.

But even considering Nashwan's data, the 109G is definitely more fuel efficient than the Spit 8 (see the 210 mph row in the Spit charts).

The Spitfire data is for IAS, it says so clearly in the chart.

The 109 data is for TAS, I think. It's at 18,000ft, and gives 2 cruise speeds, 210 and 306 mph.

If those were IAS, they would be 278 mph and 405 mph. I don't think anyone is suggesting the 109 G2 could cruise at 405 mph, especially with a drop tank, and especially not at over 5 mpg.

The Spitfire speed is 160 IAS, which is 220 TAS. The Spitfire is of course at 20,000ft, the 109 at 18,000ft, so the speeds are directly comparable.

[Nashwan]

Isegrim, thank you for the offer. I'll have to clean out my mailbox, but I'll send you my address tomorrow.

[gripen]

Originally posted by phookat
OK, we got two choices here.  These numbers come from either the Brits or the Huns.

If the Brits did it, then clearly the numbers came from real tests, since as you pointed out they didn't have the ability to do a theoretical calculation.

Nonsense, I have pointed out that nothing proves that the numbers in the report are from real life test. As noted above, the Brits certainly had ability to make theoretical calculations in the field conditions, captured engine documentation is enough to make such calculation, wind tunnels or engine test stands are not needed.

Originally posted by phookat
If the Huns did it, then it could be either theoretical or practical.

But why shouldn't it be a practical test?  Everyone else did it, including the Aussies as you mention above--despite whatever difficulty it entailed (which I still don't agree with but I can accept hypothetically).  Why not the Huns?

But given the possibility that it was theoretical, we should consider practical matters such as the exhaust fumes you mention (however I have some questions about that, see below).

In the case of the Aussies, we have a certain proof that they really did the flight tests. Do we have such proof for German figures?  What if they just calculated range by using engine data?

FAF used the Bf 109G in combat and in peace time. The numbers I quoted are from real service use and they contain taxing in the field, climb etc.

Originally posted by phookat
This is interesting information.  Can you point me to the documents which describe this (in English if possible)?  Are there any documented tests of 109 pilots flying at such speeds?

I gave the source above; "Lentäjän Näkökulma II" by Jukka Raunio, actually it's one of the Isegrim's regular sources. For english translation you can ask Virtual pilots, they have  scanned quite large amount of FAF documentation and possibly they have translated this one.

gripen

[gripen]

Originally posted by HoHun
I've just run the numbers, and I'd say the figures for the Messerschmitt are realistic.

Please enlight us on your calculations. In fact I have been wondering when HoHun jumps in with his calculations.

gripen

[VO101_Isegrim]

Originally posted by HoHun
Hi Isegrim,


I've just run the numbers, and I'd say the figures for the Messerschmitt are realistic.

Though I can't reproduce the exact combinations of speed, altitude and endurance and the RAF obviously didn't use the documented DB605A power settings, my mileage doesn't vary much if I plug in the official data.

......

Regards,

Henning (HoHun)

Hi HoHun,

could you please contact me in email? I could use some help with range calculations, could please tell me the methods you employ etc? I need that for a personal project of mine. I am wondering how the introduction of AS and D engines changed the range picture. These had higer rated alt, so I believe higher cruising speeds they enable probalby had a positive effect on range. The GLC chart comparisons of 109G-14/AM and G-14/ASM ranges also suggest that at max. continous powers.

I`d like to run some simulations to get the 109K`s max. range and endurance, in 3 forms, internal, internal + 300liter DT, internal + DT + 115 liter rear tank.

[mw]

Perhaps these documents will be of interest:

From A.I.2(g) Report No. 2149 dated 8.2.43


From A.I.2(g) report No. 2172 dated 7.5.43


Ranges and Radii of Action of German Fighters and Fighter Bombers:
Page 1
Page 2
Page 3

[VO101_Isegrim]

Apperantly the May revision is about simply substracting 20% overall allowance from the previous figures, as outlined in the accomponying doc, article 5.

http://www.fourthfightergroup.com/eagles/109grange3.jpg

"Overall allowance of 20% to cover navigational errors.. etc"

The previous doc of February appearantly does not include this extra safety allowance, however it includes a usual ~20 gallon reserve.

[MiloMorai]

It was nice of Mike to post ALL the British documents, showing dates, etc, unlike another who only just posted a partial.

[Guppy35]

Originally posted by VO101_Isegrim



Well, one is for Merlin 61, and says 450 miles. the other is for Merlin 266, ie. US-built 266, and says 434 miles.

But what about Spitfire the History, I know this is the most accurate book on the Spit, what range does it give for the Mk IX and VIII ?

 

From Spit the Hist.  As I posted previously it says the range of the Spit VIII was 660. and that's based on the 124 gallons of internal fuel.  It doesn't include the drop tanks.

For the Spit IX it says the range was between 434-980 miles.  This is based on the Spit IX over it's production going from the basic 85 gallon set up, to having the wing fuel tanks and later on the fuselage fuel tank.  It doesn't include drop tanks in that range.

Dan/Slack

[VO101_Isegrim]

That sounds fairly reasonable Guppy, and pretty much what I have seen on that. Thanks. BTW, Angie is saying something of a ca550 mile range for the the early Spit I, I am not sure what tankage this refers to, though I think it could be possible the early ones were more fuel efficient and a bit longer ranged than the later ones. Thinking I`ll get S:H for myself, after all it`s just 30 buck or so, even though I have to wait quite a bit until it arrives here. After all, it`s always nice to have a great book on a famous, classic aircraft.Will look good between a sandwhich of Mtt books on my shelf.  

[HoHun]

Hi Dan,

>For the Spit IX it says the range was between 434-980 miles.  This is based on the Spit IX over it's production going from the basic 85 gallon set up, to having the wing fuel tanks and later on the fuselage fuel tank.  It doesn't include drop tanks in that range.

I've just tried to calculate the Spitfire XIV range according to the guidelines outlined in the British documents posted here.

I've used a 20000 ft altitude and some guesswork (because the manual doesn't really tell us which power setting result in which speed).

For a 111 gallon Spitfire XIV (standard fuselage fuel tanks + wing tanks, but no rear fuselage tank or drop tank), I get an 138 mile combat radius (with 20% reserve).

(The maximum theoretical still air range would be 588 miles.)

So the RAF Fw 190A and Bf 109G combat radius figures of 145 and 135 miles respectively at 18000 ft seem quite close to what they were getting from their own planes, too.

I imagine the Spitfire IX with wing tanks might have been slightly better than the Spitfire XIV (going by reputation only), but I don't have any good data on Spitfire IX consumption.

Regards,

Henning (HoHun)

[Angus]

Isengrim
The fuel amount for that Spit I reference of mine is 85 gallons.

Hehe, and for the record, the british tests for the Spit XIV say, that the aircraft (on internal) has NO range.

[Guppy35]

Originally posted by HoHun
Hi Dan,

>For the Spit IX it says the range was between 434-980 miles.  This is based on the Spit IX over it's production going from the basic 85 gallon set up, to having the wing fuel tanks and later on the fuselage fuel tank.  It doesn't include drop tanks in that range.

I've just tried to calculate the Spitfire XIV range according to the guidelines outlined in the British documents posted here.

I've used a 20000 ft altitude and some guesswork (because the manual doesn't really tell us which power setting result in which speed).

For a 111 gallon Spitfire XIV (standard fuselage fuel tanks + wing tanks, but no rear fuselage tank or drop tank), I get an 138 mile combat radius (with 20% reserve).

(The maximum theoretical still air range would be 588 miles.)

So the RAF Fw 190A and Bf 109G combat radius figures of 145 and 135 miles respectively at 18000 ft seem quite close to what they were getting from their own planes, too.

I imagine the Spitfire IX with wing tanks might have been slightly better than the Spitfire XIV (going by reputation only), but I don't have any good data on Spitfire IX consumption.

Regards,

Henning (HoHun)

To be honest I'm lousy at the detail stuff.  I tend to go with what people tell me in terms of those who flew Spits.  As Spit XIIs were/are my passion, I know that the Spit XII with the same 85 gallons as a Spit V or IX had less range because the Griffon drank it faster.  There would be little doubt that this would be the same for the Griffon XIV as well.  The XII pilots always went with drop tanks too as standard practice.

Looking at Spit the Hist only confirms what Spit XII pilots told me as it states the range of the XII without drop tanks as 329 vs the 434 listed for the same 85 gallons in an IX.

A note in one of the Price books says the Spit XII burned 5 gallons more an hour then a Spit V, for what it's worth.

I would imagine the Griffon 60 series engines would have been similar to the Griffon IIIs and IVs in the XII in terms of fuel consumption

Regarding the Spit I.  Spit the Hist lists the range for the Spit I as 575 but also states a combat range of 395.   I imagine it all comes down to power settings etc.

Dan/Slack