DarrenW
Staff Sergeant
Cast your vote: Best US escort fighter in ETO during 1943?
SHOULD the P39 have been able to handle the Zero? Was it training or performance?
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The performance of the Allison F4R and F20R in a decent airframe is given here.
www.wwiiaircraftperformance.org/mustang/fr893.html
Engine____ Max. TAS (mph) Height (ft)
F.4R_____ 401_____________ 4,400
F.20R____ 409_____________ 10,000
Engine Max. r o c __________Time to 20,000 Service ceiling
F.4R_ 4,090 ft/min. at 800 ft__. 8.1 mins____. 31,500 ft.
F.20R 3,800 ft/min. at 6000 ft_. 6.9 mins.____ 34,000 ft.
www.wwiiaircraftperformance.org/mustang/fr893.html
Engine____ Max. TAS (mph) Height (ft)
F.4R_____ 401_____________ 4,400
F.20R____ 409_____________ 10,000
Engine Max. r o c __________Time to 20,000 Service ceiling
F.4R_ 4,090 ft/min. at 800 ft__. 8.1 mins____. 31,500 ft.
F.20R 3,800 ft/min. at 6000 ft_. 6.9 mins.____ 34,000 ft.
CORSNING
Tech Sergeant
Well, before I get some sort of momentum going, I would like to go on record as saying,
"P-39 Expert, please get off the whole P-39 would have been a good escort fighter at
20,000 ft. in the ETO or anywhere else. It just would not have happened.
There were too many other aircraft in the works that could do that mission
so much better. Concentrate on where the P-39 really shined like the
Russians did."
"P-39 Expert, please get off the whole P-39 would have been a good escort fighter at
20,000 ft. in the ETO or anywhere else. It just would not have happened.
There were too many other aircraft in the works that could do that mission
so much better. Concentrate on where the P-39 really shined like the
Russians did."
My head is now hurting. Can someone tell me any area of performance that the latest P-39 was superior to the Spitfire IX or XIV, P-51-B/C, P47 and F4U as of 25 December 1943?[/QUOTE]
1. Spitfire IX: That would be the LF Mk.IX with the Merlin 66 using +18 lbs./sq. in. boost.
2. Spitfire XIV: Not Applicable. It did not fly its first operational sortie until 28 December.
3. P-51B: That would be the P-51B-1 with the Packard (Merlin) V-1650-3 using +67" Hg.
4. P-47D: That would be the P-47D-2-something(help me here people) using water injection.
at 56"Hg. producing 2,300 hp./T.O.
5. F4U-1a: This would be without water injection. That came along in 1944.
Then someone mentioned the P-38J/L. Well that would be number 6.
6. P-38J-5: Not Applicable. First operational sortie was on 28 December 1943.
1. The P-39N was faster than the Spit 9 up to about 5,200 meters. It was generally
consider a more rugged aircraft (In more opinions than just mine). I'm old and
don't have much time left so you look it up. It definitely had the better ground
attack fire power. I do not have the rate of roll figures for the P-39N, but the D-1
was out-rolled by the Spitfire up until 355 mph.
3. The P-51B-1: It would be ludicrous to believe the P-39N could match the
Mustang's speed but it actually compared reasonably at lower levels. At
2,000 m. there speeds were 394 vs. 381 mph. 3,000 m.= 406 vs. 398 mph.
Climb rate and overall maneuverability went to the Airacobra at low-medium
altitudes. Sea level climb= 3,187 vs. 4,140 fpm., 4,000 m.=3,437 vs. 3,620 fpm.
The P-51B-1 was not able to climb with the P-39N until almost 6,000 m.
4. P-47D-22: Does anyone really need me to post the climb rate figures here?
Well, Just for fun let's use the D-10 tests with the new Curtiss 836-RC2-18
paddle-blade propeller. It managed 3,580 fpm. S.L. and 3,300 fpm./4,000 m.
This test aircraft could actually match the Airacobra at 4,500 m. It must be
kept in mind that this was a test vehicle and the actual operational Thunderbolts
climbed about 400 fpm. slower. Low and medium altitude maneuverability
go to the Airacobra. Speed?,. Sea Level: 39/47= 344/337mph., 4,000 m.= 388/394.
5. F4U-1a: Sea level climb: 3,160 fpm., 4,000m.= 2,410 fpm. The P-39N held the
advantage all the way to their service ceiling. Maneuverability: The F4U had
an early advantage in acceleration into the roll over the P-39N if it was carrying
its wing guns. Not so much against the Russian aircraft without them. The
airacobra pretty much held the edge everywhere else, at least at low and
medium altitudes.
Alright guys,
Before you all start trying to dance all over my head. Look closely at exactly the
information I have posted. I agree that every other aircraft listed here is more
versatile. I also agree that every other aircraft here was much better suited to
the utilization that they were designated. BUT for the use that the Russians
needed fighter aircraft for, the P-39N in 1943 was the best choice (in my little mind).
Glider
Captain
Its my belief that the State department did have a ban on the F engines which is why we had to have the C. Having been forced to have the C we may as well have the same engine as the P40 which is why they weren't handed. Interestingly the tests agreed that having non handed engines wasn't a problem.
I used to live within striking distance of the National Archives but not now that I have moved, so apart from some comments on websites I cannot offer firm evidence to support this
A great post Corsning, but at the end of 1943 what were the requirements in Europe?
1 long range at high altitude.
2 shorter range recon, ground attack, low level escort and air superiority missions.
In the far east almost all missions required range and carrier capability was a price worth paying.
If you are crossing the Channel in a P-39, what do you do about an Bf109 at 10,000ft? the higher you go the more you are in his territory and he can climb too, the lower you go the more you concede and the closer you are to enemy flak in the place the everyone was trying to convince Adolf that a landing would take place.
CORSNING
Tech Sergeant
Russia: Short-medium range infantry coop. I was never talking about the requirements in Europe.
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buffnut453
Captain
As usual, so much to pull apart in these statements:
- The Brits may have specified "EVERY piece of equipment" but it is the obligation of the vendor to determine whether all the requirements of the contract can be met...and if they can't, to work with the customer to determine what, if any, wriggle room there is for compromise. Not all requirements are created equal, hence there may be some wriggle-room on some requirements whereas others are effectively written in stone. Can you please provide evidence that Bell provided the Brits with ANY details of the trade space available? For example "we can't reach the required performance figures with all this extra equipment but we can get with 5% if we remove X, Y and Z." Please show the evidence that this took place rather than assuming that the Brits somehow "knew", through osmosis or otherwise, that the P-400's performance would be lacking.
- The armour plate/glass and self sealing tanks weren't just "REQUIRED BY THE BRITISH". They were operational necessities. Why is this so hard for you to comprehend? You seem to be saying that the Brits were wrong for demanding these items. Again, it was Bell's responsibility to identify the performance impacts of these changes and I'd really like you to show that Bell did this rather than dismissing any negative references with helpful trite phrases like "we've all heard this before." Maybe the reason we've heard this before is because they're true?
So instead of facts you're now projecting your own bias and opinions onto the situation. Again, please provide evidence that the British were trying to weasel out of the contract. This comes back to the question of whether Bell was fully open about the performance impacts of the various requirements being levied on the P-400. All evidence to-date suggests they weren't.
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wuzak
Captain
Lucky for the P-39 variant that it did not have to compete with the Spitfire XIV and P-38J-5 because they would not fly operational sorties for 3 days!
Possibly, those aircraft were in squadron service and ready to go on operations at December 25, 1943.
The loss of time line and how fast things were changing in 1943 is almost laughable. The first six Griffon Spitfires with 60 series engines were tested by Geoffrey Quill on 20 January !943 called Mk VIIIGs. That is a month after our P-39N entered production in USA
Changes to the aircraft were restricted to those essential to enable it to accept the new engine ... I found that it had a spectacular performance doing 445 mph at 25,000 ft, with a sea-level rate of climb of over 5,000 ft per minute.[23] I remember being greatly delighted with it; it seemed to me that from this relatively simple conversion, carried out with a minimum of fuss and bother, had come up with something quite outstanding ... The MK VIIIG, with virtually the same tail surfaces both vertical and horizontal as the Merlin MK VIII, was very much over-powered and the handling in the air was unacceptable for an operational type ... I soon realised that a new throttle box would be needed giving a much greater angular travel for the hand lever ... The next essential ... was an improvement in the directional stability and control and a new fin was drawn out with a substantial increase in area (7.42 sq. ft) and a much larger rudder and fitted to the second aircraft JF317. This, though not ideal, produced a very marked improvement in directional characteristics and we were able to introduce minor changes thereafter and by various degrees of trimmer tab and balance tab to reach an acceptable degree of directional stability and control. The enlarged fin of JF317 had a straight leading edge but for production a more elegant curved line was introduced.
— Quill[24]
I have a data card that has information from the British Air Commission Flight Section and "Bell Report 14-945-001". The card is dated 29 June 1941. I'll compare the figures with A&AEE testing done July '41 to August '42.
Bell/BAC - A&AEE
Maximum Speed:
370 mph (approximately) at 15,000 feet - 7,350 lb
355 mph (42", 3000 rpm) at 13,000 feet - 7,845 lb
355 mph (42", 3000 rpm) at 13,000 feet - 7,845 lb
Climb to 13,000 feet:
5.3 minutes - 7,350 lb
6.7 minutes - 7,830 lb
6.7 minutes - 7,830 lb
In my opinion (from reading about 601 Squadron during those dark Airacobra days), what killed the aircraft for the RAF was chronic unserviceability, and they were unwilling to put in the mountain of effort that was required to fix it - while the Soviet NII and VVS made a special case out of the P-39 and went all-out to turn it into a real fighter. No small feat - but they sure did it.
A great read here:
Early Cobra's in Soviet Aviation
DarrenW
Staff Sergeant
"4. P-47D: That would be the P-47D-2-something(help me here people) using water injection.
at 56"Hg. producing 2,300 hp./T.O.
5. F4U-1a: This would be without water injection. That came along in 1944."
Just to add more to this:
According to America's Hundred Thousand, Republic Aviation began fitting water injection systems on all P-47D-20RE models in November 1943 and by the end of the year most ADI modifications were complete on older aircraft stationed in England. It also states that on November 25th of the same year the 1,551st F4U-1A built by Vought became the first Corsair equipped with WEP from the factory.
at 56"Hg. producing 2,300 hp./T.O.
5. F4U-1a: This would be without water injection. That came along in 1944."
Just to add more to this:
According to America's Hundred Thousand, Republic Aviation began fitting water injection systems on all P-47D-20RE models in November 1943 and by the end of the year most ADI modifications were complete on older aircraft stationed in England. It also states that on November 25th of the same year the 1,551st F4U-1A built by Vought became the first Corsair equipped with WEP from the factory.
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Hear, hear... Just to add that there were other engines (AM family) with better high alt specs but some were unreliable and other given lower priority when production capacity was in deficit.
By the way, MiG-3 is good example of the aircraft which was abandoned because it was used in wrong way. Pokryshkin, who later became the most famous P-39 "promoter", flew MiG-3 in 1941 and praised it.
CORSNING
Tech Sergeant
Sorry Sir, I was just trying to make a distinction for my reply. I lowered my voice and will take a time-out
until I have learned my lesson.
CORSNING
Tech Sergeant
I was comparing "Operational" fighters.
DarrenW
Staff Sergeant
Could you explain further what you mean by "operational"? Both the P-47D and F4U-1A were operational by this time. What am I missing here? Also, you did asked people to "help you out".
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DarrenW
Staff Sergeant
There has been some discussion about how different in performance were the P-39Q and N. They did differ in armament, the two .30 cal. machine guns in each wing being replaced by a .50 cal. mounted in lower-wing gun pods. I checked wind tunnel testing concerning the extra drag of these gun pods in NACA report L5A30 to verify. NACA concluded that the CD of the airplane (in this case, a P-63) was increased by 0.0010, which amounted to a -6 mph change in level speed. So if we add 6 mph to the speed of a P-39Q we will pretty much have the speed of an average P-39N. But then again, those four missing .30 cal. machine guns had to reduce drag slightly as well. So the addition of 4-5 mph is a reasonable amount to add, but never more IMHO.
.
Altitude SpeedMPH RPM b.h.p. Man.Pr.Hg. Oil Cooler ShutterPosition Prestone Shutter Position
*16,100 389.5 3000 1125 46.7 Flush 6 turns from W.O.
**9,700 398.5 3000 1420 59.8 Flush 6 turns from W.O.
2,700 358.0 3000 1330 57.0 Flush 6 turns from W.O.
30,100 353.0 3000 655 26.7 Flush 6 turns from W.O.
Airplane does not meet Air Corps cooling requirements at any of these powers.
On the test of the P-39N the report says the oil cooler shutters "flush" and Prestone shutter 6 turns from W.O. (as above) followed by "
Airplane does not meet Air Corps cooling requirements at any of these powers. " How is this allowed was a valid test?
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