Totally different designs by two different designers but with a passing family resemblance coming as they did from the same stable. H E Chaplin who had joined the design staff at Fairey in 1930 was appointed Chief Designer in 1940 in succcession to Marcel Lobelle, said this about the Firefly design:-
"I reviewed the the specifications and the design work done previous to my appointment [on N.8/39 & N.9/39 designs previously submitted by Fairey]
, put them all on one side and set out afresh to design the best aircraft I could within the limitations of the specification."
Two things allowed the Firefly to have a smaller wing than the Fulmar:-
1. Take off and landing criteria set down in the Specs which had been relaxed a bit.
O.8/38 for the Fulmar specified a stalling speed not to exceed 56 knots and take off distance of 225 ft against a 20 knot headwind
This was relaxed in the original N.8/39 & N.9/39 Specs to 58 knots and 300ft respectively.
Then in Spec 5/40/F, which was the one that led directly to the Firefly, there was a further amendment to 68 knots and 300ft
2. The Firefly was fitted with Fairey-Youngman flaps which had the effect of increasing the wing area when deployed for take off and landing.
Chaplin's previous project at Fairey had been the FC.1 airliner cancelled in the run up to WW2
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All good points, clearly the specs were a big part of the problem with the Fulmar, from the beginning. The takeoff and landing restrictions were probably due at least in part to the small size of the early RN carriers.
But I think the requirements for landing speed were too low, while the weight was too high (probably due to other requirements, including the second crewman with all his associated kit). I don't think they needed the Fairey Youngman flaps (which add a lot of drag).
F6F-3 Hellcat 4,190 kg empty / 5,554 kg 'gross' / 6,992 kg max .... top speed 371 mph, range 945 miles, takeoff distance 335', takeoff speed 86 mph, power on stall speed 79.5 mph
F4U-4 Corsair 4,238 kg empty / 6,654 kg 'gross' / 6,592 kg max .... top speed 393 mph, range 1,005 miles
Firefly Mk. 4,388 kg empty / 6,114 kg 'gross' / 7,083 kg max ... top speed 316 mph*, range 775 miles,
One crewman and a bit cleaner wings and fuselage would probably give you a much better performing fighter. They did manage to boost the speed a lot in later versions.
*367-386 mph speed for the latest, post-war versions
** according to armoured carriers
Firefly could carry two 45 or 90 gallon drop tanks extending the range to 1,088 or 1364 miles respectively, per "Armored carriers". Though this reduced top speed to 207 / 204 mph
Hellcat and Corsair could also carry large external tanks to increase range. Both Hellcat and Corsair got faster with later marks and higher boost / water injection etc. Corsair a lot faster.
Climb was best for the Corsair, by far. Early F4U-1 climbed at 2,890 fpm, they got this to 3,000 - 3,300 fpm by 1944, but the F4U-4 with the four blade prop climbed like a rocket.
This document says 4,770 fpm initial climb, and 4.9 minutes to 20,000 ft, which is better thant I expected. Hellcat climb rate was intiially about 2,200 - 2,500 fpm initial, which is pretty bad. Later models improved that a good bit to 3,000 - 3,600 fpm.
All I could find on the Firefly's rate of climb (
from Armouredcarriers) was 2.5 minutes to 5,000 ft and 5.75 minutes to 10,000 ft. Which works out to about 2,000 fpm initial.
Clearly the design emphasis here was on range rather than performance, but the Corsair, smallest and slimmest of the three, was not only faster but had better range. And the late models (was F4U-4 even in the war?) proved that even a big bruiser of a plane like a Corsair could also be a very fast interceptor that could climb like a rocket in a pinch.
Now this is much harder with the smaller engines, as Shortround pointed out. Lets look at the smaller ones next - F4F-3, F4F-4, FM-2, Sea Hurricane, Seafire III, Seafire XIV, Fulmar, A6M2 and A6M5