Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained)

OK, I was just getting ready to unwind. Diana said, NO!
Sorry family time, but I will come back with figures that
will add respect to the P-39 (later versions) tomorrow.

Either way the P-39 with 120 gals held more than the Fw190.

Ivan1GFP said:

Hello Corsning,
I am not sure I can agree with your summary of the Soviet Union's resources of the time.
I believe most of their problems before the war was that although there WERE plenty of resources, there wasn't the industrial and educational background in the general population to support many industries.
- Ivan.

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Resources.
Industrial and educational background was on the lower level compared to more developed countries, indeed.
But still there was lack of raw materials - of some categories.. Many of those huge deposits which helped USSR to grow after WWII were not discovered yet. And those which were discovered were prohibitively expensive to develop due lack of infrastructure, energy generation, etc. Non-ferrous metals shipments of the lend lease program were very important.

Dimlee said:

Resources.
Industrial and educational background was on the lower level compared to more developed countries, indeed.
But still there was lack of raw materials - of some categories.. Many of those huge deposits which helped USSR to grow after WWII were not discovered yet. And those which were discovered were prohibitively expensive to develop due lack of infrastructure, energy generation, etc. Non-ferrous metals shipments of the lend lease program were very important.

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I don't believe you and I are disagreeing much. The Soviets had their own internal political issues at the time which were probably a greater concern to the leadership than keeping their air forces up to date. When one is more afraid of what a capable officer corps can accomplish than wanting to exploit those skilled (and possibly ambitious) officers, then there are problems. This is getting way off topic though.

- Ivan.

P-39 Expert said:

Either way the P-39 with 120 gals held more than the Fw190.

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Hello P-39 Expert,
What you are stating isn't really accurate.
The FW 190A through the A-7 and even early A-8 series had two fuel tanks as standard.
The Forward Tank was 233 Liters (61,5 USG)
The Middle Tank was 292 Liters (77.1 USG)
The Aft Fuselage Tank which was optional on some models became standard during the A-8 production run and added 115 Liters (33.3 USG).

So.... Early models would have had 138.69 Gallons and Late models would have had 169 Gallons of internal fuel.

Note also that the FW 190 series could carry a lot of external stores or fuel which the Airacobra could not.

- Ivan.

Ivan1GFP said:

Hello P-39 Expert,
What you are stating isn't really accurate.
The FW 190A through the A-7 and even early A-8 series had two fuel tanks as standard.
The Forward Tank was 233 Liters (61,5 USG)
The Middle Tank was 292 Liters (77.1 USG)
The Aft Fuselage Tank which was optional on some models became standard during the A-8 production run and added 115 Liters (33.3 USG).

So.... Early models would have had 138.69 Gallons and Late models would have had 169 Gallons of internal fuel.

Note also that the FW 190 series could carry a lot of external stores or fuel which the Airacobra could not.

- Ivan.

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You guys are much sharper than I on these two aircraft. My question is how did they stack up or compare range wise. I'm assuming the radial had a higher gallon per mile covered or greater fuel burn than the inline (V12) of the P39?

Cheers,
Biff

P-39 Expert said:

P-39 actually held lots of fuel when compared to European planes. More than the Spitfire and Me109 and more than a Fw190 based on gallons to displacement.

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Was looking for a Spitfire IX data sheet and found this - fuselage tank mods for a long range IX
http://www.spitfireperformance.com/spitfire9-fuelsystem-lr.jpg

I think the date is 1945, but I can't tell for sure.

The standard IX had 85 imperial gallons, which is 102 USG. Which is less than the 120USG that some P-39s had, but more than most P-39s had (87USG).

This long range Spitfire had 96 UKG forward of the pilot and 66 or 74UKG behind the pilot, depending if it had the standard or cut down rear fuselage.

MK VIIIs had 96 UKG forward tanks as standard and 13 UKG in each wing, for a total of 122UKG. This carried over to the XIV.

I'm not sure if IXs ever got the leading edge tanks. I suspect not.

In any case, it appears that the Spitfire had more space where fuel could be added, even if that could cause stability issues (eg rear tanks).

BiffF15 said:

You guys are much sharper than I on these two aircraft. My question is how did they stack up or compare range wise. I'm assuming the radial had a higher gallon per mile covered or greater fuel burn than the inline (V12) of the P39?

Cheers,
Biff

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Definitely had higher gallons per hour, mainly because they had more power.

Air miles per gallon depends on what that extra power does for speed.

wuzak said:

Definitely had higher gallons per hour, mainly because they had more power.

Air miles per gallon depends on what that extra power does for speed.

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Ranges for each? I'm curious as I've always looked at the Fw190 and Me109 as very short ranged or point defense fighters and if the P39 is similar it changes how I have historically perceived it.

Cheers,
Biff

wuzak said:

Which is less than the 120USG that some P-39s had, but more than most P-39s had (87USG).

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According to some of the sources referenced earlier in this thread, the 87 gallon Cobras were in the minority, being primarily the early marks of the N series and early Ds and prior models, many of which were retrofitted to higher capacity.
Cheers,
Wes

British figures for P-39D2 (V1710-63)

Petrol: 100 gallons
Take-off and climb to 15,000: minus 21.5 gallons
Range at most econ: 630 miles (minus 76 miles for every 5 min of combat)
Range at max weak mix: 450 miles (minus 54 miles for every 5 min of combat)

Combat: 3000 rpm and 60 inches

Wuzak

Per the Spitfire Mk XI, my sources indicate that the Mk XI converted from MK IX airframes did not have the leading edge wing tanks (about 50), the rest did (about 420). The wing tanks held 66.5 gallons each, giving a total tankage of 218 gallons total (85 in fuselage and 123 in wings)

Sources: Supermarine Spitfire by Peter Moss, Spitfire-The Story of a Famous Fighter by Bruce Robertson

Also if you look at the test of a Mk XI on Mike Williams' and Neil Stirling's site, you will find that the Aircraft had leading edge tanks.

FYI

Eagledad

eagledad said:

Wuzak

Per the Spitfire Mk XI, my sources indicate that the Mk XI converted from MK IX airframes did not have the leading edge wing tanks (about 50), the rest did (about 420). The wing tanks held 66.5 gallons each, giving a total tankage of 218 gallons total (85 in fuselage and 123 in wings)

Sources: Supermarine Spitfire by Peter Moss, Spitfire-The Story of a Famous Fighter by Bruce Robertson

Also if you look at the test of a Mk XI on Mike Williams' and Neil Stirling's site, you will find that the Aircraft had leading edge tanks.

FYI

Eagledad

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I think there has been a misunderstanding.

The VIII and XIV had small, 13UKG, tanks housed inside the inner leading edge of the wing.

Theoretically those tanks could have been put into the IX as well. But I don't believe they were.

The XIs, the ones not converted from the IX, got a different wing with a different structure, which allowed the leading edge tanks to span most of the wing.

BiffF15 said:

Ranges for each? I'm curious as I've always looked at the Fw190 and Me109 as very short ranged or point defense fighters and if the P39 is similar it changes how I have historically perceived it.

Cheers,
Biff

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Sorry Biff, I wasn't able to get a reliable range for either.

Someone else help?

The P-39 was a slick aircraft (low drag) but it was heavy. It did do pretty well in miles per gallon but a lot of these aircraft were pretty close together and does a 10-20% change in range really amount to all that much operationally?

Like if plane "A" has a operational radius if 100 miles and plane "B" has an operational radius of 120 miles and you are dealing with the English channel which can be 100 miles wide (or more) in some spots what is the practical difference?
Even on the Eastern front, sometimes a battle will be that grey zone where plane B can reach it from a certain airfield but plane A can't but how often is that going to happen where there isn't one or more airfields closer to the battle that Plane A couldn't stage through, either going or coming.


Here is the range chart for a P-39Q-1.
http://zenoswarbirdvideos.com/Images/P-39/P39FOIC.pdf

down low (0-6000ft) at 250-260mph it can do about 260 miles after subtracting 6-17 gallons for warm up and take off. WIth 120 gallon tanks (105 usable) it should do about 390 miles at that speed but there is no allowance for either combat or for finding home base and landing. Slower speeds give more range and max continuous less.

In British terms the P-39Q comes out like this for 5 minute fuel usage.

Cruise condition..................5 min at Military power...........5 min at WEP
Max cruise 3.125mpg.................36 miles................................44 miles
Intermed (2nd column)...............44 miles................................53 miles
most economical........................74 miles................................90 miles

Fractions rounded off.

Spitfires were all over the place in regards to fuel capacity. with 102 US gallons on the early ones. 146 US gallons on the MK VII & VIII, 114 US gallons on some late MK IXs

And then you have the fact that the Spitfire could operate with the 36 gallon Slipper tank (perform all combat maneuvers?) , how often this was done I don't know.
Apparently it was only the Griffon engined MK XIV that used the 108 US gallon slipper tank in combat?
Unknown to me is if the 54 US gallon slipper tank was ever used in combat.

By used in combat I mean the plane did not drop it when engaging the enemy. I have no idea if there were fuel feed problems with any of theses slipper tanks or if there was a problem with fuel sloshing around if the tank was part full. (how much internal baffling there was? Or how strong the attachment points were.

My Apologies to our commonwealth members but I figured I would keep all fuel in US gallons to help eliminate confusion.

The Pilot manual for the Fw190A-8 has range data.
Pilot manual flugzeug handbuch focke wulf fw 190a 8 english ocr

BiffF15 said:

Ranges for each? I'm curious as I've always looked at the Fw190 and Me109 as very short ranged or point defense fighters and if the P39 is similar it changes how I have historically perceived it.

Cheers,
Biff

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The contemporary (1945?) data shows the 109G making 615 miles on internal fuel (88 imp gals), and 1000 miles with the usual 66 imp gal drop tank: table
For flying under unspecified conditions.*
That is quite a good result, a tad better than the Spitfire with 2-stage Merlin aboard and 85+90 imp gals. Please note that a Tempest V with 188 imp gals of internal fuel will make 850 miles (and 1770 with 2x90 gal tanks), unfortunately that improvement came about too late, well in second half of 1944. Also note the useful increase in range when Spitfires are outfitted with rear fuel tanks.

*seems like most economical speed: picture

Gents,

If I read correctly then the 109 and 39 had very similar ranges. SR6 I looked at your chart and found a max range of just over 400 miles but could not read any of the notes. Regardless I'm assuming both were fairly short legged by US standards when compared to P38s and P40s, which would have been their contemporaries (?). For some reason I thought the P39 had better legs than that.

Thanks for the info gents!

Cheers,
Biff

Shortround6 said:

Apparently it was only the Griffon engined MK XIV that used the 108 US gallon slipper tank in combat?
Unknown to me is if the 54 US gallon slipper tank was ever used in combat.

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As previously posted in the P-38 thread, Spitfire IX combat with 90 gallon drop tank attached:
http://www.wwiiaircraftperformance.org/126-Rae-14aug44.jpg

Spitfire XIV combat with 45 gallon drop tank attached:
http://www.wwiiaircraftperformance.org/41-coleman-20april45.jpg