Did the Wildcat airframe have any growth left in it?
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Shortround6
Major General
Probable not. Several proposals were made to mount the R-2600 in it but none left the paper stage which may tell us something. At least one request was by the Navy and the other one (or two?) were by Grumman. Work on these proposals helped speed up initial work on the F6F (originally to mount the R-2600) which also may tell us something.
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What about a P&W 2000 or a Wright 2600? Could the airframe handle it? The Spitfire and ME109 got bigger and bigger engines right up to the end, could the same have been done with the Wildcat. I know the Hellcat was the way to go, but if it handn't been built, could the Wildcat have continually been improved?
Shortround6
Major General
When the Hawk was re-engined with the Allison the Allison did not produce more power than the radials it replaced. It offered much lower drag with roughly equal power. As the Allison gained power ( and perhaps for other reasons) the P-40 began to show lateral instability which was solved by lengthening the fuselage by 20 inches. The FM2's with the 1300/1350hp Wright engines got taller tails to counter act the increased torque. F8F-2 have bigger tails than F8F-1s. Spitifire fins and rudders grew in several stages.
The DB-7/A-20 went from R-1830s to R-2600 and also "grew" a substantially bigger vertical fin.
Sometimes it is blamed on increase area forward of the CG or increased propeller "activity" forward of the CG, or torque and sometimes the increase in speed means the plane handles differently (many planes used an offset vertical fin or one that was "cocked' in relation to the fuselage axis as a crude form of "trim"). But whatever the the reason, large increases in power usually required a change in vertical fin/rudder area or longer fuselages to increase the movement arm. The P-40 kept the horizontal stabilizer in roughly the same place, the vertical fin and rudder were moved back in relation to the Horizontal stab.
It can obviously be done if needed but points to the fact that an engine swap involves much more than just what happens from the firewall forward. Propeller technology also has to keep pace with power output. 4 and 5 blade propellers were a bit late in coming for some aircraft. F4Us, F6Fs, Hawker Typhoons and such used some mighty big 3 blade propellers because 4 bladed ones were either unavailable or weren't working real well ( early P-47?). Using much more powerful engines that need bigger props affects landing gear, and even wing design or placement. DO you want to try adding 6-8 in to the landing gear of an F4F or P-36 in order to clear the bigger prop an R-2600 is going to need? F4F had taxiing problems as it was. Lower the wing, put landing gear in the lowed wing. extend rear fuselage, make vertical fin bigger, it's still an F4F right?
The DB-7/A-20 went from R-1830s to R-2600 and also "grew" a substantially bigger vertical fin.
Sometimes it is blamed on increase area forward of the CG or increased propeller "activity" forward of the CG, or torque and sometimes the increase in speed means the plane handles differently (many planes used an offset vertical fin or one that was "cocked' in relation to the fuselage axis as a crude form of "trim"). But whatever the the reason, large increases in power usually required a change in vertical fin/rudder area or longer fuselages to increase the movement arm. The P-40 kept the horizontal stabilizer in roughly the same place, the vertical fin and rudder were moved back in relation to the Horizontal stab.
It can obviously be done if needed but points to the fact that an engine swap involves much more than just what happens from the firewall forward. Propeller technology also has to keep pace with power output. 4 and 5 blade propellers were a bit late in coming for some aircraft. F4Us, F6Fs, Hawker Typhoons and such used some mighty big 3 blade propellers because 4 bladed ones were either unavailable or weren't working real well ( early P-47?). Using much more powerful engines that need bigger props affects landing gear, and even wing design or placement. DO you want to try adding 6-8 in to the landing gear of an F4F or P-36 in order to clear the bigger prop an R-2600 is going to need? F4F had taxiing problems as it was. Lower the wing, put landing gear in the lowed wing. extend rear fuselage, make vertical fin bigger, it's still an F4F right?
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- #6
Shortround6
Major General
We have a lot of threads on this. The R-2600 is a possibility but not IMHO a good one. The P&W R-2000 is a no chance in HE** choice. Nice engine but it comes AFTER the R-2800 NOT before it. By the time P&W make the first 9 (end of Dec 1941) they have made over 1400 R-2800s and Ford has made 264, P&W have even made 6 of the two stage R-2800 engines. The R-2000 is about 100lbs heavier than an equivalent R-1830 ( single stage 2 speed) and while it offers more power down low (an extra 150-250hp) this becomes a much smaller difference at altitude. 2 speed R-1830s could manage 1000hp at 14,500ft. The 1450hp take off R-2000s could manage 1100hp at 17,000ft military rating (2700rpm) the two stage R-1830 was about the same weight (not counting intercoolers and ducts) and offered 1000hp at 19,000ft at 2550 rpm in spite of using 2700rpm for take off.
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- #8
I never have much luck trying to do searches on old threads. Sounds like my questions have been asked and answered before. I didn't know the timeline of the engines either. Once you have the R2800 out, the only logical thing to do is to build an airframe around it.
Shortround6
Major General
Yes, P&W were putting most of their R&D into the R-2800 and R-4360. The R-1830 got some "trickle down" improvements late in the war and the R-2000 was answer to a question that never came up (it could give 1200hp for take off on 87 octane fuel in case there was shortage of 100 octane according to one story) and was only ever used in the C-54/DC-4 and a few re-engined C-47s. Rather than spend money on the R-2000 P&W split the R-4360 into the R-2180 post war for the 1500-1600hp 14 cylinder market but only sold about 90 engines. Airframe makers quickly jumped to 40-50 seat twins powered by R-2800s rather than try to build 28-40 seat twins powered by 1830-2180 cu in engines, there were too many cheap surplus C-47s to make a smaller, lower performing airplane a viable product.
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- #10
CobberKane
Banned
- 706
- Apr 4, 2012
I think it's fair to say that if you put progressively more and more power into an existing airframe you will at the very least run into the law of diminishing returns, and very possibly create some major problems as well. The Spitfire seems to have been something of a qualified exception to this rule, managing to retain its flyability even as it's performance was greatly increased but, significant as the Wildcat was, I don't think anyone would claim it's design had anything like the development potential of the Spit. Doubling the Wildcat's horsepower probably would have had all sorts of nasty consequences. I think Grumman got it exactly right with the FM-1; a modest increase in power and trim off some excess weight and hey presto – a useful second tier fighter with no bugs to be worked out.
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- #12
oldcrowcv63
Tech Sergeant
Cobber, I suspect you meant to say FM-2 and not FM-1 as there was no increase in power for the FM-1 which was simply an F4F-4 with a reduced 4 gun armament.
From a thread posted a few days ago:
http://www.ww2aircraft.net/forum/av...-design-efforts-g-33-g-35-xf2m-1-a-34710.html
"...the XF2M-1 was an attempt to design/produce a super FM-2 Wildcat using P&W R-2000 or Wright R-2600, started in October 1942 but canceled in 1945, before completion of a prototype. Evidently it was slow rolled by BuAer which was basically satisfied with the FM-2 and didn't want to interrupt production. That strongly suggests to me there was some life left in the old bird and room for some improvement."
Info from Rene Francillon's Grumman Aircraft since 1929:
From a thread posted a few days ago:
http://www.ww2aircraft.net/forum/av...-design-efforts-g-33-g-35-xf2m-1-a-34710.html
"...the XF2M-1 was an attempt to design/produce a super FM-2 Wildcat using P&W R-2000 or Wright R-2600, started in October 1942 but canceled in 1945, before completion of a prototype. Evidently it was slow rolled by BuAer which was basically satisfied with the FM-2 and didn't want to interrupt production. That strongly suggests to me there was some life left in the old bird and room for some improvement."
Info from Rene Francillon's Grumman Aircraft since 1929:
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jimh
Senior Airman
Yes, it's called the Bearcat 
JH
JH
CobberKane
Banned
- 706
- Apr 4, 2012
Yep, I did indeed mean FM-2. I understand that one of the big attractions of the uprated Wildcat was that it was small enough to fit on the escort carriers, which the Hellcat was not. Maybe bigger is not always better.
MikeGazdik
Senior Airman
Did the Wildcat airframe have any growth left in it?
My first thought is.....No. Then the more I think about it, my answer is No. lol
My first thought is.....No. Then the more I think about it, my answer is No. lol
oldcrowcv63
Tech Sergeant
Well, whatever your thoughts and opinion, they are evidently not in accord with Eastern and Grumman Aircraft's engineering department.
That's what makes this an interesting question.
Hi, oldcrow,
Care to elaborate a bit? Have the Eastern and Grumman thinkered about a significant modification of the FM/F4F?
oldcrowcv63
Tech Sergeant
From a thread posted a few days ago (Below) and from post number 13 in this thread:
http://www.ww2aircraft.net/forum/av...iation/aviation/aviation/avi...1-a-34710.html (Little Known Grumman design efforts: G-33 G-35 and the XF2M-1)
"...the XF2M-1 was an attempt to design/produce a super FM-2 Wildcat using P&W R-2000 or Wright R-2600, started in October 1942 but canceled in 1945, before completion of a prototype. Evidently it was slow rolled by BuAer which was basically satisfied with the FM-2 and didn't want to interrupt production. That strongly suggests to me there was some life left in the old bird and room for some improvement."
According to Rene Francillon's Grumman Aircraft since 1929:
The XF4F-8 (FM-2 prototype) was powered by the Wright R-1820-56, while later models were variously powered by R-1820-56A, -56W and -56WA engines
The first flight of the XF4F-8 (prototype for the FM-2) was 8 November 1942
the actual quote regarding the XF2M-1 follows:
"At the behest of USN BuAer, and with the assistance of their colleagues at Grumman, Eastern Engineers studied various ways of increasing the FM-2's level speed and climb performance (and presumably its performance at altitude-my note) by substituting more powerful engines in cleaned up airframes. The use of two types of twin row radials, the P&W R-2000 and W R-2600, was quickly rejected and plans were made to use more powerful versions of the Cyclone single row radial either the Wright R-1820-62 or -70W. Although the design work had been started in October 1942, it had almost immediately been slowed down as BuAer wanted to avoid delays which would result from production switch from FM-2s to F2M-1s. Three XF2M-1s had been ordered but the contract canceled in the Spring of 1945."
According to: http://www.americancombatplanes.com/f4f_2.html
the R-1820-70W was turbo-charged.
Of course as has been stated by others here, the importance of escort carriers was central to this issue. The smaller fighters were apparently better suited to operation from small flight decks probably for a variety of reasons. (increase in air group size as well as performance at low speeds)
Also, in early 1943, the USN/Grumman tested the two XF4F-5s (bureau number 1846 1847) with doubly-supercharged (1847) and turbo-charged (1846) Cyclone engines. The former performed better at low altitude while the latter was able to make 340 mph at 26,400 ft. While this performance would certainly have suffered with implementing a full combat rig including armor and SSTs, I suspect these variants, had they reached production stage would have improved Wildcat performance somewhat. Was it worth a switch in production? probably not. Introduction of the FM-1 2 worked to correct much of pilot's dissatisfaction with the F4F-4 type and the advent of the F6F and F4U also changed the essential mission of the F4F's still operating by the end of '43.
So it seems to me this makes any suggestion that there was no room for F4F improvement after the FM-2, demonstrably false.
http://www.ww2aircraft.net/forum/av...iation/aviation/aviation/avi...1-a-34710.html (Little Known Grumman design efforts: G-33 G-35 and the XF2M-1)
"...the XF2M-1 was an attempt to design/produce a super FM-2 Wildcat using P&W R-2000 or Wright R-2600, started in October 1942 but canceled in 1945, before completion of a prototype. Evidently it was slow rolled by BuAer which was basically satisfied with the FM-2 and didn't want to interrupt production. That strongly suggests to me there was some life left in the old bird and room for some improvement."
According to Rene Francillon's Grumman Aircraft since 1929:
The XF4F-8 (FM-2 prototype) was powered by the Wright R-1820-56, while later models were variously powered by R-1820-56A, -56W and -56WA engines
The first flight of the XF4F-8 (prototype for the FM-2) was 8 November 1942
the actual quote regarding the XF2M-1 follows:
"At the behest of USN BuAer, and with the assistance of their colleagues at Grumman, Eastern Engineers studied various ways of increasing the FM-2's level speed and climb performance (and presumably its performance at altitude-my note) by substituting more powerful engines in cleaned up airframes. The use of two types of twin row radials, the P&W R-2000 and W R-2600, was quickly rejected and plans were made to use more powerful versions of the Cyclone single row radial either the Wright R-1820-62 or -70W. Although the design work had been started in October 1942, it had almost immediately been slowed down as BuAer wanted to avoid delays which would result from production switch from FM-2s to F2M-1s. Three XF2M-1s had been ordered but the contract canceled in the Spring of 1945."
According to: http://www.americancombatplanes.com/f4f_2.html
the R-1820-70W was turbo-charged.
Of course as has been stated by others here, the importance of escort carriers was central to this issue. The smaller fighters were apparently better suited to operation from small flight decks probably for a variety of reasons. (increase in air group size as well as performance at low speeds)
Also, in early 1943, the USN/Grumman tested the two XF4F-5s (bureau number 1846 1847) with doubly-supercharged (1847) and turbo-charged (1846) Cyclone engines. The former performed better at low altitude while the latter was able to make 340 mph at 26,400 ft. While this performance would certainly have suffered with implementing a full combat rig including armor and SSTs, I suspect these variants, had they reached production stage would have improved Wildcat performance somewhat. Was it worth a switch in production? probably not. Introduction of the FM-1 2 worked to correct much of pilot's dissatisfaction with the F4F-4 type and the advent of the F6F and F4U also changed the essential mission of the F4F's still operating by the end of '43.
So it seems to me this makes any suggestion that there was no room for F4F improvement after the FM-2, demonstrably false.
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