Favorites and their achilles heels!

[Juha]

One thing I don't understand in this F4F-4 business, why didn't USN pilots just remove the outer .5s. That would not have helped in firing time problem, but they would have gotten lighter plane, even lighter than F4F-4 with 4 HMG and more rpg that they wished. After all the guns were not welded in their places. All what was needed was a bit initiative and disobedience onboard CVs far out on sea.

Juha

 

[oldcrowcv63]

Juha, GREAT Question and one I've asked myself on occasions too numerous to count.

My only answer is to cite the incredible resistance to any airframe modifications and control exerted by BuAer that persists to the present day, you fly with the configuration they give you, even if it kills you. That's my answer, based on my experience and I'm stickin to it until somebdy tells me it's not true, then I'll dive like dolphin. You have to understand that the USN for all its modern technological bent is one of the most conservative, hide-bound institutions on the planet (next to the politbureau).

I say this as someone who loves the USN but I am sure I'll catch flack for this post. Oh well. let it come..

BuAer told pilots, "if you don't like it and want longer firing time, deselect the two outer guns and keep them for a get-me-home reserve! But BuAer didn't understand then that the 45 seconds or so difference in climbing time to 20,000 feet was important. Many well informed people still don't think it was important to this very day.

 

[pinsog]

One thing I don't understand in this F4F-4 business, why didn't USN pilots just remove the outer .5s. That would not have helped in firing time problem, but they would have gotten lighter plane, even lighter than F4F-4 with 4 HMG and more rpg that they wished. After all the guns were not welded in their places. All what was needed was a bit initiative and disobedience onboard CVs far out on sea.

Juha

I have often wondered that about the F4F-4, the P39 in American service, and the P40 in American service. I'm not sure the latter 2 wouldn't have been much better aircraft if they just had 2 synchronized .50's, and of course the P39 with the hub cannon changed to a 20mm and ditch ALL of the wing guns on both of those aircraft.

 

[oldcrowcv63]

The only in-theater or field modifications I can think of off-hand are those done to the Fifth Air Force B-25, authorized by Kenney in the South Pacific. Not sure if there are any others. I can't think of any done by the USN maybe someone else can recall one.

 

[Shortround6]

In "America's Hundred Thousand" and in the specification sheets available at Spitfire performance testing including:

http://www.wwiiaircraftperformance.org/f4f/f4f-4-detail-specification.pdf

Show weights and performance with 4 guns and 800 rounds (called normalfighter) 4 guns plus bombs and 6 guns with 1440 rounds (called overload fighter). Similar variations in guns and ammo load can be found for other Wildcat models. For USN Brewster Buffaloes and F4U Corsairs. It doesn't seem like the 6 gun fit was mandatory from on high.

AS far as not listening to their own pilots and listing to the British ???? the timing doesn't look good for this story, they may have listened to the British but with 5 F4F-4 delivered by the end of Dec 1941, the contracts and Specifications had been agreed to well before the USN Pilots had any combat experience with the F4F-3 or F4F-4. First flight of a 4 gun Eastern Aircraft FM-1 was in Aug of 1942. They seem to have gone back to the 4 gun setup rather quickly. When was the 'DECISION" made to go back to four guns? perhaps even before any combat experience from Guadalcanal?

 

[Shortround6]

I have often wondered that about the F4F-4, the P39 in American service, and the P40 in American service. I'm not sure the latter 2 wouldn't have been much better aircraft if they just had 2 synchronized .50's, and of course the P39 with the hub cannon changed to a 20mm and ditch ALL of the wing guns on both of those aircraft.

The P-39 may have been OK ( the Russians flew a lot of theirs that way) the P-40 might have been a very iffy aircraft. The .50 did not take to synchronization very well with rates of fire dropping as low as 450rpm in some British tests.

 

[pinsog]

The P-39 may have been OK ( the Russians flew a lot of theirs that way) the P-40 might have been a very iffy aircraft. The .50 did not take to synchronization very well with rates of fire dropping as low as 450rpm in some British tests.

Wouldn't a P39 set up with only 2 .50's and a 20mm through the hub been better armed than an ME109 in the BoB? ME109 during BoB had rifle caliber synchronized guns didnt it?

 

[Shortround6]

Wouldn't a P39 set up with only 2 .50's and a 20mm through the hub been better armed than an ME109 in the BoB? ME109 during BoB had rifle caliber synchronized guns didnt it?

Yes the P-39 would have been better armed but then by the time it was in service in any numbers it was a year after the BoB and the standard for fighter armament was moving on. Instead of comparing it to a 109E you should be comparing it to a 109F.
And then we are back to the two 1000rpm rifle caliber machine guns vs two 500rpm .50 cals (actually the .50s are in better shape as we are comparing them gun for gun rather than 2 RCMG vs a single .50) but the P-40 with only two guns is in rather poor shape firepower wise. Better than an Oscar and few other aircraft but barely passing out an Italian fighter with a pair of of 12.7mm Breda-SAFAT machine guns.
Compared to a 109F the paired sychro-ed .50s don't really equel the 15mm MG 151 by itself and are well under 1/2 the fire power of the 20mm MG 151.

 

[pinsog]

Yes the P-39 would have been better armed but then by the time it was in service in any numbers it was a year after the BoB and the standard for fighter armament was moving on. Instead of comparing it to a 109E you should be comparing it to a 109F.
And then we are back to the two 1000rpm rifle caliber machine guns vs two 500rpm .50 cals (actually the .50s are in better shape as we are comparing them gun for gun rather than 2 RCMG vs a single .50) but the P-40 with only two guns is in rather poor shape firepower wise. Better than an Oscar and few other aircraft but barely passing out an Italian fighter with a pair of of 12.7mm Breda-SAFAT machine guns.
Compared to a 109F the paired sychro-ed .50s don't really equel the 15mm MG 151 by itself and are well under 1/2 the fire power of the 20mm MG 151.

A P40 with 2 .50's wouldn't be my 1st choice for fighter, and I wouldn't be as concerned about how well the 2 .50's shot down other planes as I would that shedding all that weight might keep ME from getting shot down! I wouldn't want a 2 .50's fighter if I was fighting the Luftwaffe, but I think it might have worked fine against the Japanese.

As far as the P39, shedding 4 .30's and 1000 rounds per gun might have made a BIG difference. Just another "what if" though.

 

[Shortround6]

.As far as the P39, shedding 4 .30's and 1000 rounds per gun might have made a BIG difference. Just another "what if" though.

Not really a "what if" but more of a "who if". Like I said the Russians often operated their P-39s either without the wing guns or with the wing guns taken out.

 

[Shortround6]

A P40 with 2 .50's wouldn't be my 1st choice for fighter, and I wouldn't be as concerned about how well the 2 .50's shot down other planes as I would that shedding all that weight might keep ME from getting shot down! I wouldn't want a 2 .50's fighter if I was fighting the Luftwaffe, but I think it might have worked fine against the Japanese.

You might be better off ditching the .50s and replacing them with .30 guns with 500rpg. Ditching the wing .30s saves 94.4lbs and the ammo weighs another 127.4 lbs.

swapping the cowl .50s for .30s saves just over 100lbs and the .50cal ammo weighed 228lbs. trading 760 rounds of of .50 cal for 1000 rounds of .30 cal saves another 163lbs.

Then we can argue if 16-18 rounds per second of .50 cal ammo equals 105-110 rounds per second of .30cal

 

[oldcrowcv63]

AS far as not listening to their own pilots and listing to the British ???? the timing doesn't look good for this story, they may have listened to the British but with 5 F4F-4 delivered by the end of Dec 1941, the contracts and Specifications had been agreed to well before the USN Pilots had any combat experience with the F4F-3 or F4F-4. First flight of a 4 gun Eastern Aircraft FM-1 was in Aug of 1942. They seem to have gone back to the 4 gun setup rather quickly. When was the 'DECISION" made to go back to four guns? perhaps even before any combat experience from Guadalcanal?

Well, I have to say your time line does look persuasive. Let me try to reconstruct it as reported in Don Linn's Squadron Signal Pub and other sources:
August 1939: Grumman awarded a contract for 54 fixed-wing (G-36) F4F-3 A/C, supercharged P&W 1830-76 with 2 nose .3 in MG and 1 x .5 in. in each wing.
Late 1939: French Purchase 81 G-36A with 4 x .3 in MG Wright Cyclone 1820 engine with 1 stage 2 speed supercharger
January 1940: first production G-36/F4F-3 comes off line. P&W 1830 with 2 stage, 2 speed supercharger begins fleet evaluation.
Early 1940, 3rd production F4F-3 modified armament to 4 x .5 inch HMG with 450 rpg.
Early 1940 Belgium orders 10 G-36As of uncertain specs.
Early 1940: Britain orders 100 fixed-wing G36B with a P&W 1830 with 1-stage, 2 speed supercharger with 6 x .5 in MG
March 1940: USN contracts Grumman to produce a folding wing F4F.
Spring 1940: Britain changes order for G-36B to be folding wing version (Martlet II)
USN immediately accomodates Britain to avoid production delays and makes XF4F-4 a 6 gun rig, with 240 rpg
11 May 1940: First G36A flies with 7 produced before France Falls. Britain takes over French Belgium order.
27 July 1940: first Martlet Mk I is delivered to be upgraded to British requirements (By Blackburn apparently)
August 1940: first 6 Martlet I's arrive in Britain. These A/C become Martlet Mark I.
Late 1940: USN Orders 95 F4F-3A with P&W 1930-90 signgle stage 2 speed Superchargers
25 December 1940: 2 Martlet I's of FAA 804 quadron shoot down a Luftwaffe JU-88 (first US Built A/C to shoot down an axis A/C)
January, 1941: first two squadrons of F4F-3 A/C become operational and commence training cruise deployments.
March thru May 1941: 95 F4F-3A delivered with 30 being set aside for Greece but taken in hand by FAA western Desert squadron.14 April 1941: XF4F-4 first flight
Early 1941: USN contracts Grumman for 1,169 F4F-4. at 190 A/C produced per month
October 1941: Wildcat name adopted by USN
November 1941, F4F-4 deliveries begin
January 1942: Fleet squadron pilots get their first look at the XF4F-4 during initial Pacific island raids and don't like it.
Early 1942: Navy Department brings GM to Grumman to transfer production to GM's future Eastern Aircraft Division.
14 June 1942: BuAer issues order for a 4 gun installation on Eastern's F4F-4 production variant to be known as FM-1. Change to commence with the 11th FM-1 produced. Grumman F4F-4 production was completed unchanged to production end (Early 1943).
Summer 1942, first folding wing 6 gun Martlet II's delivered to FAA.
August 31:1942 First FM-1 flight
F4F-4 production ceases in early 1943 with 1169 F4F-4 and 320 Martlet II and IV
Spring 1943: FM-1 first operational deployment
Mid 1943: FM-1 production ceases with 830+ USN 4 gun A/C and 311 FAA Martlet V with 6 guns.

The battle reports on the F4F-4 from Midway, Eastern Sol.and Santa Cruz damned it for performance and firing duration. Prior to those battles, the XF4F-4 was deployed with the shipboard squadrons in the Pacific and considered unsuitable as a replacement for the -3. In response to early complaints, BuAer ordered changes to the 4 gun installation in the upcoming FM-1 in June 1942. The 6 gun Grumman production was retained to supply residual USN and FAA needs until replaced by FM-1s from the Eastern Aircraft plants converted to Wildcat manufacture, with separate USN FAA production lines.

The first production 4 gun FM-1s came off the line in September 1942 but didn't see action until 1943.

There was, according to every source I've seen, no attempt to change the F4F-4 despite the poor reports coming in from the Pacific. There were still many F4F-4s to produce and could be changed in time to make a difference. The FAA was insistent according to the sources but I really don't even know if a proposal to change was submitted to them. I am ready to believe that Towers covered his 6 o'clock with this story. but I don't know.

 

[oldcrowcv63]

A P40 with 2 .50's wouldn't be my 1st choice for fighter, and I wouldn't be as concerned about how well the 2 .50's shot down other planes as I would that shedding all that weight might keep ME from getting shot down! I wouldn't want a 2 .50's fighter if I was fighting the Luftwaffe, but I think it might have worked fine against the Japanese.

The P-40B (with 2 x 0.5 inch and 4 x 0.3 inch guns) flown by the AVG apparently did very well against the Japanese Oscars and readily achieved altitude advantage whereas the USAAF P-40Es with 6 x 0.5 inch guns rarely scored on the Zeros they met over the PI and Java. They couldn't reach the altitude of incoming raids and apparently virtually never achieved altitude advantage over Japanese aircraft. The ceiling reduction with the extra weight amounted to about 3-4,000 feet or more.

 

[Glider]

oldcrow posting 152 was excellent.
Only one minor amendment and that was the item on the 25th Dec about the Wildcat being the first US built aircraft to shoot down a German aircraft. On the 8th October 1939 a Hudson shot down a German aircraft over Jutland.

 

[Juha]

The P-40B (with 2 x 0.5 inch and 4 x 0.3 inch guns) flown by the AVG apparently did very well against the Japanese Oscars and readily achieved altitude advantage whereas the USAAF P-40Es with 6 x 0.5 inch guns rarely scored on the Zeros they met over the PI and Java. They couldn't reach the altitude of incoming raids and apparently virtually never achieved altitude advantage over Japanese aircraft. The ceiling reduction with the extra weight amounted to about 3-4,000 feet or more.

One thing to be remember is that AVG had a good air surveillance system, so it usually got timely warning on Japanese raids, so P-40Bs had time to achieve altitude advantage.

Juha

 

[oldcrowcv63]

oldcrow posting 152 was excellent.
Only one minor amendment and that was the item on the 25th Dec about the Wildcat being the first US built aircraft to shoot down a German aircraft. On the 8th October 1939 a Hudson shot down a German aircraft over Jutland.

Thanks Glider, had not heard of that!

 

[tomo pauk]

The 1 20mm cannon + 2 HMGs (with LMGs deleted) for P-39 sounds good to me; the cannon being belt-fed, of course.

 

[oldcrowcv63]

One thing to be remember is that AVG had a good air surveillance system, so it usually got timely warning on Japanese raids, so P-40Bs had time to achieve altitude advantage.

Juha

Very true, but a RADAR based fighter direction system was operational on December 8 in the PI but failed miserably apparently because the ground to air comms were so bad and pilots took matters into their own hands to the detriment of their efforts.

The Java based early warning and fighter direction system was apparently somewhat similar to that of the AVG, but could only provide about 30 minutes of warning to the interceptors. Reading Bartsch, it appears that time and again, the P-40E's reach their ceiling and watch the bombers fly past above them by about 3,000 feet while the Zero escorts dive down on the USAAF pilots from their perch above the bombers and just tear into them. The P-40E's only survival tactic was to dive away which didn't always work.

 

[drgondog]

There is an 800 pound difference between P-40B and P-40E. 240 pounds difference between 4x30 + 2x50 vs 6x50. installation but only 70 pounds difference in ammo weight. So overall the E weighed about 500 pounds more on Basic weight with ammo added.

The E had 1100 hp allison, the B had 1040.

The B's top speed was achieved at 15K, the E at 12K.

Offhand, except for implied blower impeller setting difference which gave the P-40B its top speed at 15K, 3000 feet higher than the P-40E, is the only rational explanation for the E having better climb to 20K performance. The E should do better to 12K with small weight difference but more power up to 12K.

 

[oldcrowcv63]

There is an 800 pound difference between P-40B and P-40E. 240 pounds difference between 4x30 + 2x50 vs 6x50. installation but only 70 pounds difference in ammo weight. So overall the E weighed about 500 pounds more on Basic weight with ammo added.

The E had 1100 hp allison, the B had 1040.

The B's top speed was achieved at 15K, the E at 12K.

Offhand, except for implied blower impeller setting difference which gave the P-40B its top speed at 15K, 3000 feet higher than the P-40E, is the only rational explanation for the E having better climb to 20K performance. The E should do better to 12K with small weight difference but more power up to 12K.

Good stuff, but in the data I've seen it wasn't so much the climb rate that was the problem as the ceiling. The P-40E just couldn't get its ass above 29,000 ft when 'new' and as time on the engine accumulated, that altitude decreased.