XP-39 II - The Groundhog Day Thread

[gordonm1]

i'm not sure if it fits here but were the P39 and P40 all steel and the P51 aluminum? Curious about the aluminum P40 what if....

 

[GregP]

P-39 and P-40 are aluminum airplanes. At least the ones operated by the Planes of Fame are. There is some steel, but the structure is aluminum. Landing gear oleos are steel along with a few other items. The engine crankshaft, camshaft, and other parts are steel, but the engine case is aluminum. Mixed material is normal due to strength and heat requirements.

If you tried out aluminum valves in the engine, they wouldn't last longer than a couple of minutes, if that long. In an Allison V-1710, the valve are Stellite (cobalt-chromium alloy) with powdered sodium fill for heat dissipation.

 

[windhund116]

P-39 and P-40 are aluminum airplanes. At least the ones operated by the Planes of Fame are. There is some steel, but the structure is aluminum. Landing gear oleos are steel along with a few other items. Th engine crankshaft, camshaft, and other parts are steel, but the engine case is aluminum. Mixed material is normal due to strength and heat requirements.

If you tried out aluminum valves in the engine, they wouldn't last longer than a couple of minutes, if that long. In an Allison V-1710, the valve are Stellite (cobalt-chromium alloy) with powdered sodium fill for heat dissipation.

I'd imagine a cast-iron block engine would yield an airplane which is capable of taxiing. Only.

Were the valve seat also made of Stellite? Very strong material.

 

[pbehn]

i'm not sure if it fits here but were the P39 and P40 all steel and the P51 aluminum? Curious about the aluminum P40 what if....

A lot of duralumin or variants of it Duralumin - Wikipedia

 

[jmcalli2]

1700hp at sea level only.

Still, that's 300 more than the highest takeoff HP in a P-39 that I know of, in the Q model.
It could be why the Russians did so well with the P-39.

 

[jmcalli2]

Hello jmcalli2,

Those were not Nick which is a twin engine fighter. They were Ki 27 Nate which is a little tiny fighter with fixed landing gear.
The other thing worth mentioning is that from the Curtiss aircraft Construction Numbers, the batch of "P-40s" which were technically just "Hawk 81s" fell into the range for the P-40C and not P-40B.
Curtiss basically used the contract to get rid of old parts that would not satisfy current military contracts because the contract fr the Chinese did not specify a lot of features that the military contracts did. So much for Mil-Spec.
That is why older fuel selectors without provision for drop tanks and fuselage fuel tanks with external sealing material were found on these planes. The folks in China saw these pieces and thought they were flying earlier models, but they were not.



That document you found is the Allison Memo that I have mentioned a few times. I didn't find it on that site though.
The engines models they cover are not actually the ones you are thinking though.
They were the F3R (V-1710-39 and V-1710-35) and F4R (V-1710-73 and V-1710-63). Basically the 1150 HP and 1325 HP engines for the P-40 and P-39.
This is probably why the P-39D-1 pilot flying against the Aleutian A6M2 probably figured he could run a LOT more boost than the manual allowed.

- Ivan.

Thanks for the correction on the Nates. I blame spell check. LOL

Good points.

 

[jmcalli2]

Interesting. Couple books and articles I've read said the units (like 8th FG) with P400 fared not-so-well against the IJNAF fighters, early in those New Guinea air battles. Later, these early units were replaced with P40s.

I think it was along the lines of, 'escort mission covering B-25s (or B-26s or B-24s) along with P-40s.' I'll have to look for it to be sure I'm recalling it correctly.

 

[jmcalli2]

I think it was along the lines of, 'escort mission covering B-25s (or B-26s or B-24s) along with P-40s.' I'll have to look for it to be sure I'm recalling it correc

tly.

OK, I was confusing the P-38 book with the P-39 book; the P-38s were on escort missions with P-40s.
The P-39s fought with RAAF Kittyhawks in New Guinea, mostly on intercept missions. The P-39s did escort RAAF B-26s, USAAF B-25s, A-20s, and A-24s.
Here are a few screen shots:

 

[BiffF15]

Book - "Luftwaffe Test Pilot" by Hans Werner-Lerche
Here are some of the Allied planes he tested, I believe some are estimates on his part such as range, but everything else seems to be from his data. Not sure why he has the Mustang's climb performance only to 5k when the Thunderbolt's got to 20 and 25k, or the Airacobra only to 5k.

FWIW here's his rather simplistic chart, not a lot of "in depth" data, he just has the basics listed:

Type | Max Speed | Climb | Ceiling | Range

American

B-17F | 325MPH @ 25,000ft | 20,000 - 25min 42sec | 37,500ft | 4,420 miles

B-17G | 302MPH @ 25,000ft | 20,000ft - 37min 0sec | 35,000ft | 1,800 miles

B-24D | 303mph @ 25,000ft | 20,000ft - 22min 0sec | 32,000ft | 1,800 miles

B-24J | 300mph @ 30,000ft | 20,000ft - 25min 0sec | 35,000ft | 1,700 miles

B-26B | 317mph @ 14,500ft | 15,000ft - 12min 0sec | 23,000ft | 1,150 miles

P-39D | 335mph @ 5000ft | 5,000ft - 1min 54sec | 29,000ft | 600 miles

P-47D-2 | 420mph @ 30,000ft | 20,000ft - 11min 0sec | 42,000ft | 835 miles

P-47D-10 | 433mph @ 30,000 | 25,000 - 15min 0sec | 42,000ft | 835 miles

P-51B | 446mph @ 30,000ft | 10,000ft - 1min 48sec | 42,000ft | 2250 miles

British

Lancaster Mk 1 | 281mph @ 11,000ft | 20,000ft - 41min 36sec | 24,500 | 1,730 miles

Wellington Mk IV | 247mph @ 14,500ft | 10,000ft - 18min 0sec | 17,700ft | 2,250 miles

Tempest Mk V | 426mph @ 18,500 | 15,000 - 5min 0sec | 36,500ft | 1,530 miles

Typhoon Mk IB | 405mph @ 18,000ft | 15,000 - 6min 12sec | 34,000ft | 1,000 miles

Spitfire Mk IIA | 357mph @ 17,000ft | 20,000ft - 7min 0sec | 37,230ft | 406 miles

Peter,

Thank you! The numbers look fairly close (I don't have them memorized). Did the Germans use Allied fuel to get these results? Did Allied fighters and bombers use the same grade fuel? I would guess it was all the same...

Cheers,
Biff

 

[BiffF15]

Hello BiffF15,

The FW 190 was a particularly nice handling aircraft. The British acknowledged in their testing of a captured example.
In another, there was the possibility of the aircraft not having the ailerons set up properly which caused a few issues.
In comparison, even some of the other users of the Lavochkin fighters were not so impressed with their handling.
They just had the engine power and performance that prior Soviet fighters lacked.

If flown by the manual, the 1180 mm Hg @ 2500 RPM setting was only good for about 5 minutes and only useable in Low Blower.
This would give 1850 HP and in theory was a Take-Off setting and not useful much past 1650 Meters critical altitude for low blower.
The equivalent of military power was 1700 HP with 1000 mm Hg @ 2400 RPM in Low Blower.

From what I have been able to find, climb rate at "military power" was somewhere under 3500 fpm which is good but not that special, but at its take-off setting, climb rate is about 4000 fpm which was very competitive for the time.

I have a lot more detail in the Soviet manuals for the aircraft if you wish to calculate the actual fuel consumption of the aircraft for range purposes. One odd thing to note is that the fuel in the Rechlin report seems to weigh more than the typical 6 pounds per US Gallon that one might expect.

I believe that in this particular test at Rechlin, the Germans may have captured the La 5FN AFTER it had been beaten to heck by the prior Soviet users. Soviets didn't tend to stick by the manuals with the Airacobra and probably didn't with anything else either. It generally didn't matter when the lifespan of an aircraft measured in weeks.

Regarding the Zero and Japanese claims for speed. From what I can tell, there actually are no official claims for what we would consider "Maximum Speed".
In their manual for the A6M2, they only list a maximum speed for "Normal Power" +50 mm @ 2350 RPM which is what we might consider max continuous or something close and that was for 275 Knots or 316 MPH.
The 345 MPH claim was by an experienced pilot, Saburo Sakai. For a long time, I was certain this number was inaccurate but not because Sakai was dishonest, but after reviewing the reports recently and other sources in the context of these discussions, I am now more certain he was correct.

- Ivan.

Ivan,

I can easily see the Russian pilots over boosting their planes, for the simple reason as you said they didn't tend to last long. Also, as for the P39 it was someone else who was building it and its engines, so no skin in the game and it was truly an asset to be used up and thrown away. And it appeared to have less vices than their indigenous production.

As for the Zero and it's top speed I agree. I always thought of it being a 350'ish type of plane mostly because of what the combat reports said (Allied pilot reports). It's fairly easy to compare your planes performance to another even in a fight. It's quite obvious who is faster, and by how much, or who turns / climbs better and by what sort of margin.

Cheers,
Biff

 

[Mike Williams]

Did the Germans use Allied fuel to get these results? Did Allied fighters and bombers use the same grade fuel? I would guess it was all the same...

Cheers,
Biff

Allied bombers generally used 100/130 grade fuel while USAAF 8th AF Mustangs used 100/150 GRADE FUEL starting in early June 1944. 9th AF used 100/130 grade after moving to the continent. RAF Mustangs, some Spitfires, Mossies and Tempests starting using 100/150 Grade in ADGB (Air Defense of Great Britain) during the summer of 44, with 2nd TAF fighters switching over in early 45 on the continent.

 

[Mike Williams]

OK, I was confusing the P-38 book with the P-39 book; the P-38s were on escort missions with P-40s.
The P-39s fought with RAAF Kittyhawks in New Guinea, mostly on intercept missions. The P-39s did escort RAAF B-26s, USAAF B-25s, A-20s, and A-24s.
Here are a few screen shots:

What's the book? Some operational history and pilot's accounts of the P-39 would be most welcome here instead of the endless drama over trivial matters and ongoing personal smears.

 

[tomo pauk]

What's the book? Some operational history and pilot's accounts of the P-39 would be most welcome here instead of the endless drama over trivial matters and ongoing personal smears.

(my bold)
I have nothing against keeping the bolded stuff in a single thread, vs. having to wade through that multiple threads...

 

[windhund116]

Ivan,

I can easily see the Russian pilots over boosting their planes, for the simple reason as you said they didn't tend to last long. Also, as for the P39 it was someone else who was building it and its engines, so no skin in the game and it was truly an asset to be used up and thrown away. And it appeared to have less vices than their indigenous production.

As for the Zero and it's top speed I agree. I always thought of it being a 350'ish type of plane mostly because of what the combat reports said (Allied pilot reports). It's fairly easy to compare your planes performance to another even in a fight. It's quite obvious who is faster, and by how much, or who turns / climbs better and by what sort of margin.

Cheers,
Biff

At least before 1945, most Russian pilots fought over Russian soil. So, if they fried an engine --- bailing out & survival was not as harrowing, as a German pilot bailing out over the same territory.

 

[BiffF15]

Allied bombers generally used 100/130 grade fuel while USAAF 8th AF Mustangs used 100/150 GRADE FUEL starting in early June 1944. 9th AF used 100/130 grade after moving to the continent. RAF Mustangs, some Spitfires, Mossies and Tempests starting using 100/150 Grade in ADGB (Air Defense of Great Britain) during the summer of 44, with 2nd TAF fighters switching over in early 45 on the continent.

Mike,

I would not have guessed that, however it stands to reason due to shear quantities. What happened when a fighter guy diverted / landed short at a bomber base, did they have a supply of the 100/150 or did he get 100/130 and use lower power settings on the way home?

Cheers,
Biff

 

[pbehn]

Mike,

I would not have guessed that, however it stands to reason due to shear quantities. What happened when a fighter guy diverted / landed short at a bomber base, did they have a supply of the 100/150 or did he get 100/130 and use lower power settings on the way home?

Cheers,
Biff

On missions from the UK, when really short of fuel returning planes landed at the three emergency bases set up for the purpose RAF Manston Woodbridge or Carnaby. I presume they had all sorts of fuel, they had everything else.

 

[Mike Williams]

Mike,

I would not have guessed that, however it stands to reason due to shear quantities. What happened when a fighter guy diverted / landed short at a bomber base, did they have a supply of the 100/150 or did he get 100/130 and use lower power settings on the way home?

Cheers,
Biff

Hi Biff,
One example that comes to mind is Operation of Spitfire IX LF with 25 lbs/sq.in. Boost. "Aircraft may land at an airfield where only 130 grade (normal 100 octane) fuel is available. The pilot should always bear in mind that it is not harmful to use this fuel provided he does not REPEAT not exceed 18 lbs. boost." 8th AF mustangs could use 2nd TAF's 150 grade on the continent beginning in early 1945, otherwise I presume they would use 9th AF stocks of 100/130 fuel and limit boost for the ride home.

 

[Mike Williams]

Does any one know what kind of fuel Russian P-39s used?

 

[GrauGeist]

Does any one know what kind of fuel Russian P-39s used?

Not sure what was used in the Soviet P-39 specifically, but they did have aviation fuel that ranged from 70 to 85 octane, with fuel supplied to them by the Allies that was 95 and 100 octane.

The lower octane fuel was used in older aircraft types.

 

[Juha3]

Does any one know what kind of fuel Russian P-39s used?

front line units usually used 91-95 oct Soviet fuels or 100 oct LL fuel (outside mid-1942 - early 43, when Soviet fuel supply was in crisis), I have seen Soviet speed graphs for P-39Q showing the speeds with 95 and 100 oct fuel. Soviet 95 oct was usually used by M-82F and FN engines, so La-5F, -FN, La-7 and Tu-2. Spitfires and P-39s used usually 100 oct LL fuel. IIRC one big offensive was delayed a couple of days so that they could store enough LL fuel for a P-39 fighter division for the operation.