Can we make a faster better performing Wildcat in 1942?

[EwenS]

A long time ago (early- to mid-1990s?) I ran across a mention and photos of tests done on a Wildcat with RATO. IIRC it was the British or Canadians doing the testing.

The RAE at Farnborough took an interest in using rockets for "non-projectile use" from late 1939 initially to assist in getting heavy bombers airborne before switching to the possible use by the RN. Practical trials began around April 1941 (a Blackburn Shark was an early guinea pig for the trials) and continued into the mid-1950s when steam catapults began to be the standard fit on carriers.

Heavy bomber interest waned in Aug 1941 after a 4 engined Stirling was written off after the rockets all fired together from an underwing mounting in an airframe not designed to cope with the sudden stress. All this in full view of an audience that included high ranking RAF officers and a cabinet minister! There is a photo in existence of an earlier successful rocket assisted take off on that aircraft.

RN interest continued because British aircraft types were not compatible with the catapults on the US built escort carriers beginning to be made available under Lend Lease and because British built escort carriers (except Pretoria Castle) and MAC ships were not equipped with catapults at all. So it saw operational use on Swordfish (especially the Mk.III in 1944/45) & Barracudas. While I don't recall seeing photos of US types with it, I've no doubt they were trialled with RATOG at Farnborough at some point in WW2.

Barracuda II making a rocket assisted take off from the very wet deck of HMS Trumpeter

 

[ThomasP]

Found a video of USN JATO (aka RATO?) tests on the F4F, F4U, F6F, SBD, and TBF.


View: https://youtu.be/eZLso0R42Jc

Also, a photo of a Wildcat using JATO, at NAS Jacksonville in 1944.

 

[Admiral Beez]

There was a prototype F6F-4 with a single stage R-2800-27:

I wonder how fast a R-2800 equipped Wildcat could go in level flight with the RATO rockets firing. I'm guessing close to 430 mph for a period.

 

[RCAFson]

I wonder how fast a R-2800 equipped Wildcat could go in level flight with the RATO rockets firing. I'm guessing close to 430 mph for a period.

I don't think an F4F airframe could accommodate an R-2800. The RATO rockets only provide a few seconds of thrust.

 

[don4331]

I wonder how fast a R-2800 equipped Wildcat could go in level flight with the RATO rockets firing. I'm guessing close to 430 mph for a period.

About 20mph? As soon as you released the tiedowns holding the tail down, the Wildcat would nose over and plow on the prop until the JATO rocket burned out. R-2800 is way too much weight for an F4F.

 

[don4331]

The US could have made some changes in 1940-41-42 simply by not insisting that each and every fighter plane carry a trailer load of guns and ammo

And yet the pilots voiced all sorts of objections when ammo load out was reduced from 450 to 240 rpg.

And I have some sympathy for them - at the time, they were the pointy end of the spear and there was no radar/IFF warning system. The limited number (?4?) planes in air and at altitude would be forced to defend again the entire incoming attack. The carrier might be lucky to get turned into the wind, let alone launch additional aircraft before coming under attack.

By the time of the FM-2, the Wildcat pilots were no longer at the front lines - Hellcats were, and radar/IFF meant a much better CAP could be in place. So. only having 240 rpg for 4 guns was no longer big issue.

So, building an earlier F4F-8 (Prototype FM-2) isn't going to be popular with the USN pilots (even if performance is improved).

 

[Wild_Bill_Kelso]

And yet the pilots voiced all sorts of objections when ammo load out was reduced from 450 to 240 rpg.

And I have some sympathy for them - at the time, they were the pointy end of the spear and there was no radar/IFF warning system. The limited number (?4?) planes in air and at altitude would be forced to defend again the entire incoming attack. The carrier might be lucky to get turned into the wind, let alone launch additional aircraft before coming under attack.

By the time of the FM-2, the Wildcat pilots were no longer at the front lines - Hellcats were, and radar/IFF meant a much better CAP could be in place. So. only having 240 rpg for 4 guns was no longer big issue.

So, building an earlier F4F-8 (Prototype FM-2) isn't going to be popular with the USN pilots (even if performance is improved).

They might not like the 240 rounds, but they didn't seem to mind the four guns on the F4F-3 and I bet they would love the improved climb rate and speed.

Hawk 87 type P-40s had about 280 rounds per gun, sometimes less (closer to 200 rounds for P-40L and stripped P-40Fs), and often (at least in the Mediterranean) just four guns, and they did quite well. As did the F4F-3, in fact the USN seemed to have trouble making CAP intercepts in the F4F-4 era which may have had something to do with the terrible climb rate.

Speaking of Wildcats, I was reading about the Fw 200 and was reminded what an impact the Martlet had. Six early Martlets (I think these were the particularly slow ones) on the early / experimental escort carrier conversion HMS Audacity shot down seven Fw 200s while escorting four convoys between Sept and Dec 1941, before being sunk by a U-boat on 14 Dec 1941.

 

[don4331]

The 1st RN Martlet with P&W engine doesn't roll off the line until Aug. '41, by which time HMS Audacity has been at sea for over a month.

The Martlets aboard Audacity were ex-French "G-36A"s: Export version of F4F-3, which had Wright R-1820s. Not sure if Blackburn installed armour/self sealing tank when they replaced French 7.65mm guns with 50s, radios with RN ones, and reversed the French throttle controls. Those Martlets might have been the lightest/fastest below 20k' Wildcats at the time.

 

[Wild_Bill_Kelso]

The 1st RN Martlet with P&W engine doesn't roll off the line until Aug. '41, by which time HMS Audacity has been at sea for over a month.

The Martlets aboard Audacity were ex-French "G-36A"s: Export version of F4F-3, which had Wright R-1820s. Not sure if Blackburn installed armour/self sealing tank when they replaced French 7.65mm guns with 50s, radios with RN ones, and reversed the French throttle controls. Those Martlets might have been the lightest/fastest below 20k' Wildcats at the time.

Ah, very interesting! And that does make more sense !

 

[EwenS]

The 1st RN Martlet with P&W engine doesn't roll off the line until Aug. '41, by which time HMS Audacity has been at sea for over a month.

The Martlets aboard Audacity were ex-French "G-36A"s: Export version of F4F-3, which had Wright R-1820s. Not sure if Blackburn installed armour/self sealing tank when they replaced French 7.65mm guns with 50s, radios with RN ones, and reversed the French throttle controls. Those Martlets might have been the lightest/fastest below 20k' Wildcats at the time.

"Grumman Aircraft since 1929" by Francillon notes that the Martlet I were fitted with their revised armament (2x0.5" in each wing) before being flown to Canada for handover to Britain. Similarly throttle operation was reversed to standard British operation and some British instrumentation and and radio equipment fitted. No mention of self sealing tanks. Eric Brown (of test pilot fame) who joined 802 squadron when it formed as a young Sub-Lieutenant noted that the "all the instruments were calibrated in metric units, although all other traces of its originally-intended Gallic recipient had been removed."

AIUI these modifications were carried out by Grumman as the timing pre-dates Blackburn's association with Grumman (the French contract was only signed over to Britain at 0330 on 17 June 1940 just 5 hours before the USA froze French assets). On arrival in Britain between Aug & Sept 1940 (a final batch of 10 were lost at sea in Oct) they were sent to Scottish Aviation Limited at Prestwick Scotland for assembly before issue to squadrons, beginning with 804 in Oct 1940. Part of 804 broke away in Nov 1940 to form 802 squadron augmented by newly qualified pilots like Eric Brown.

Brown noted that the Martlet I was good for a climb rate of 3,300ft/min (no altitude given) but max speed 265 knots (305mph) at 15,000ft and 248 knots (285 mph) at sea level was slower than advertised.

 

[Wild_Bill_Kelso]

And these had armor as far as you know? Probably the best solution for the RN / FAA was to issue these early F4F-3 types instead of what they ended up being sent.

 

[EwenS]

There is a heap of detail about Martlet/Wildcat production especially about the order of production, visible changes between models etc etc over on the Britmodeller site on a thread that started last year by guys who have dived into both British and Grumman records:-

All the Wildcat/Martlet questions you wanted to ask

The various wildcat/Martlet variants and their features have been the subject of much discussion and the latest topic has strayed from its original question to a wider discussion concerning engine variants, production details and other matters. Other relevant posts include There are many others A...

www.britmodeller.com

The differences between the G-36A / Martlet I and the F4F-3 are far greater than just the engine, running to the wing structure amongst other things.

You need to read the whole thread start to finish as additional info comes to light.

 

[Thumpalumpacus]

Speaking of Wildcats, I was reading about the Fw 200 and was reminded what an impact the Martlet had. Six early Martlets (I think these were the particularly slow ones) on the early / experimental escort carrier conversion HMS Audacity shot down seven Fw 200s while escorting four convoys between Sept and Dec 1941, before being sunk by a U-boat on 14 Dec 1941.

I'm pretty sure Eric Brown got one of those kills right before the ship was sunk, maybe a day or two before?

 

[Wild_Bill_Kelso]

The ability to shoot down Fw 200s doesn't sound too impressive, compared to other fighter ace feats, until you read a bit about the early convoys and the horrific losses they were suffering.

 

[don4331]

I'm pretty sure Eric Brown got one of those kills right before the ship was sunk, maybe a day or two before?

Eric Brown got his 1st Fw.200 kill on 8/Nov'41 (a little after 2 pm) as part of convoy OG-76 which sailed from British Isles on 28/Oct/'41 arriving in Gibraltar on about 11/Nov/'41. His 2nd Fw.200 was on 19/Nov ("later in morning"). HMS Audacity was sunk on 21/Dec/'41.

 

[Thumpalumpacus]

Eric Brown got his 1st Fw.200 kill on 8/Nov'41 (a little after 2 pm) as part of convoy OG-76 which sailed from British Isles on 28/Oct/'41 arriving in Gibraltar on about 11/Nov/'41. His 2nd Fw.200 was on 19/Nov ("later in morning"). HMS Audacity was sunk on 21/Dec/'41.

Thanks for the correction. I knew it was close in time but obviously thought it closer.

 

[Barrett]

The 6 guns get a lot of the Blame.
I am not saying that the 6 guns were a real good idea, just that they get all of the blame for the wing fold, the 150lbs of self sealing material for the fuel and oil tanks and the 120lbs of pilot protection.

Difference between 4 guns with 430rpg and 6 guns with 240rpg was 63lbs. The 4 gun planes didn't have to carry 430rpg and with 330rpg they could save about 120lbs.

The early Martlet Is may have had the slow firing early .50 cal guns, which jammed a lot, and they used the older lower velocity/lower powered ammo.

I don't KNOW if that had any influence on the British decision to ask for 6 guns but it does seem plausible.

According to Grumman factory records I accessed in the 70s (creak) the six-gun armament was done partly in deference to the Royal Navy, which of course opposed German aircraft far more than Japanese at that point. But several of the aces I knew (including Joe Foss, Marion Carl, Swede Vejtasa and George Wrenn) said they considered the extra two guns as get-me-home insurance. That was aside from the fact that the dash four Wildcat had less trigger time than the four-gun dash three. I remember Jimmy Thach saying "A pilot who will miss with four guns will miss with eight."

When secretary of the fighter aces assn, I crunched a bunch of Frank Olynyk's numbers, comparing four-gun v. six-gun effectiveness in F4Fs, P-51s, etc. The results were pretty consistent: the 50 percent increase in firepower only yielded a 10 percent increase in lethality, based on credits for destroyed-probables-damaged.

As for upgrades: whatever may have been decided, it's extremely unlikely they could have reached fleet squadrons in 1942 owing to the screaming need for dash fours throughout the year. Production-line changes would unnecessarily have delayed deliveries.

Also consider this: Jimmy Flatley of VF-10 wrote, "Let us know disparage our equipment. It shoots the enemy down in flames and brings us hone most of the time."

 

[Wild_Bill_Kelso]

According to Grumman factory records I accessed in the 70s (creak) the six-gun armament was done partly in deference to the Royal Navy, which of course opposed German aircraft far more than Japanese at that point. But several of the aces I knew (including Joe Foss, Marion Carl, Swede Vejtasa and George Wrenn) said they considered the extra two guns as get-me-home insurance. That was aside from the fact that the dash four Wildcat had less trigger time than the four-gun dash three. I remember Jimmy Thach saying "A pilot who will miss with four guns will miss with eight."

When secretary of the fighter aces assn, I crunched a bunch of Frank Olynyk's numbers, comparing four-gun v. six-gun effectiveness in F4Fs, P-51s, etc. The results were pretty consistent: the 50 percent increase in firepower only yielded a 10 percent increase in lethality, based on credits for destroyed-probables-damaged.

As for upgrades: whatever may have been decided, it's extremely unlikely they could have reached fleet squadrons in 1942 owing to the screaming need for dash fours throughout the year. Production-line changes would unnecessarily have delayed deliveries.

Also consider this: Jimmy Flatley of VF-10 wrote, "Let us know disparage our equipment. It shoots the enemy down in flames and brings us hone most of the time."

That is really fascinating stuff, I appreciate the numerical analysis too.

From pilot interviews I've read of P-40 and P-51 pilots, they usually mentioned wanting the two extra wing guns for strafing missions. I don't think they had trouble shooting down enemy aircraft, as you say - if they could hit them.

 

[Barrett]

I wonder how fast a R-2800 equipped Wildcat could go in level flight with the RATO rockets firing. I'm guessing close to 430 mph for a period.

How about refiguring the F4F airframe's VASTLY changed weight & balance to install that honking big engine?

 

[Shortround6]

According to Grumman factory records I accessed in the 70s (creak) the six-gun armament was done partly in deference to the Royal Navy, which of course opposed German aircraft far more than Japanese at that point.

I have pointed this out before. We may be comparing 3 different things.
1. British Martlet Is four .50 cal guns.
2. US, F4Fs (or P-40s or P-41s) with four .50 cal guns. (not the same thing)
3. US fighters and later Martlets with six .50 cal guns.

The British were definitely using lower powered .50 cal ammo in 1940 and 1941 and quite possibly later. The 2500fps ammo instead of the 2880 fpm (or at least over 2800ftp) that the US shifting to in 1940/41. Much more kinetic energy and shorter time of flight.
The US also changed the rate of fire of .50 cal machine guns in 1940/41. It took 4 of the new guns to equal 5 of the old ones. In fact six of the new guns equaled the same number of bullets per second as eight of the old ones. This assumes you could even get the full 600rpm out of the old guns.

What never comes to light is why the British made their request?
In 1940 the only experience the RN (or RAF) had with the .50 cal guns was with 11 Buffalos in England in July/Aug, the 81 Martlet Is (ex French) which showed up in Sept/Oct, and some Tomahawk Is. Experience was far from good, guns not firing at the promised rates of fire, guns jamming a lot, an awful lot. What we don't know is if the poor experience was related to request for the increase in guns or not.

By the time we get to P-51Bs they had not only the faster firing guns with higher veleocity ammo, they had M8 API ammo. The M8 API was also showing in large quantities in the Navy stocks of ammo in late 1943.
IN 1940 there was no incendiary .50 cal ammo. They were trying to develop it on both sides of the Atlantic. British didn't think the US stuff was worth issuing.

Six .50s firing at 780rpm is 78 rps.
Four .50s firing at 600rpm is 40 rps.
780rpm is a bit low for a 1942-43 gun, 600rpm is optimistic for a 1940 gun.
Six .50s firing at 600rpm is 60 rps.
Four .50s firing at 780rpm is 52 rps.


I could very well be on blind or false trail. There doesn't seem to much in writing on the why.