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Over 380 mph at S/L depending who you talk toThe F5F may have been good for 312mph at sea level and 358mph at 17,000ft ?
AgreeThe F5F had very good take-off performance. Landing speed might have been a bit high for British taste. But better than a Whirlwind.
Say, British make a fighter with 300 sq ft wing, powered by two Kestrels, armed with 10-12 Brownings, later up-engined with Merlins.
Well, F5F with 2400hp doing 380mph (?) after drag reduction programOver 380 mph at S/L depending who you talk to
It doesn't - but many of the sources I've been coming up with show that 380mph at sea level the recorded maximum speed. I've been trying to find an official flight test report, even one from Grumman.Well, F5F with 2400hp doing 380mph (?) after drag reduction program
333 mph?
Engines on the F5F are each bigger than the R-2800
F5F would have been faster at sea level than P-47M using 2800hp.
Something doesn't seem right.
Best I have seen isIt doesn't - but many of the sources I've been coming up with show that 380mph at sea level the recorded maximum speed. I've been trying to find an official flight test report, even one from Grumman.
Skipping over what I found to be a confusing preamble (that's on me), and focusing on the question rather than the merits of the aircraft, I'd say Japan would benefit the most having 2-engined fighters. IJAF twin-engined interceptors like the Ki-83, J5N and Ki-96 can attack B-29 raids with less worry of long range, more agile single-engine escorts. And if we want to look at merits, their fast twins look wicked.What airforce benefits the most? For whom going full steam 2-engined is actually a bad idea, not least because of industry, logistics and budget limitations (Italy, Japan?)
the same assumptions leads to the similar solutions - at least usual... Soviets have started working on this one at the period when PZL-38 have been dropped in favour of it's "bigger brother" PZL-48 which never reached prototype phase...
What do you want the twin engine plane to do???
What I was getting at is that the 2 two engine fighter should do something the single fighter could not.
The US 37mm is a bit confusing. In the Airacuda the guns used 5 round magazines. The early P-39 used a 15 round feed system. it didn't get the 30 round system until a bit later.
This is one reason the Airacuda got a 5 man crew.
People knew the cannon were coming, but it was hard to know exactly when to to leap on the horse. Especially for the single seat aircraft as you need a reliable feed system of large capacity or you are wasting you money.
If the guns won't fire more than a few seconds the extra range/endurance isn't as useful.
For the Americans having four .50 cal guns that worked (and they often didn't in the late 30s) was better than two 37mm guns that didn't.
But building 20 twin engine fighters may not get you anything that 40 single engine fighters won't. depends on range and years and the engine situation.
As you know, I like the Whirlwind. Had it been pushed harder in might have done a lot more but it was never going to be an escort fighter. It's wing was smaller than a Hurricane. Without a major redesign it had limitations. It was never going to be a bomb truck either unless very short range.
But using twin Merlins to haul 12 .30s when you have fighters with single Merlins hauling eight guns doesn't make sense. Unless you can use them at long range.
Give the pilots gunnery training rather than trick fighters
And the difference might only be a year or two. The P-38 snuck in under the wire but if the P-38 didn't show up when it did would it really do much the P-47 could not?
Once the R-2800 showed up the need for the US to make twin engine fighters using 1200-1425hp engines went away. The production lines were set up and they were useful but they were sort of a duplication. (assuming they sort out the P-47 drop tank problem sooner).
Kelly designed the P-38 to be a twin because he didn't have a 1500hp single engine available at the time.
High drag radial vs less drag with a water cooled V-12?People at Boeing have had a 1500 HP engine available for 1938 when the Clipper 1st flew.
High drag radial vs less drag with a water cooled V-12?
Which is more than a little late.People at Boeing have had a 1500 HP engine available for 1938 when the Clipper 1st flew.
Drag of one radial engine vs. drag of two V12s.
We are scrambling times line here. In 1938 an R-1830 was a 1050hp engine for take-off. It wouldn't get to 1200hp until mid 1940 in production (and needed 100 octane fuel)For the Americans, a 2-engined fighter can be heavily armed and still perform well. A fighter powered by a single R-1830 might be under-performing with two 37mm M4 cannons under the wings, ammo feed and supply is hndered by the restrictive space in the wings. A 2-engined fighter has far more leeway with ammo supply and feed, and the load is shared by two engines instead of just one.
Well, it is questionable if the six .50s were a good idea for R-1830s and V-1710s of 1942-43 let alone for 1938-40Until the 37mm issues are sorted out, we might, possibly, make an alternative weapon set-up that holds 6 belt-fed .50s...
Six .50s with ample ammo supply will be too much to carry and still perform for the 1-engined fighters powered by R-1830s and V-1710s of the era.
Problems with the twin Kestrel is that the Kestrel is over 100lbs lighter than the Peregrine. Change to the Merlins is not impossible but is more difficult.It is easy to like the Whirly. RAF didn't want to have their fighters being used as bomb trucks - fighters are supposed to shoot bombers over the UK, making any other suggestion a heresy.
British (and other) need to start early and with a design that is not tailor-made for a particular engine type. I've suggested going with a bit bigger airframe, 280-300 sq ft wing etc. With Kestrels, it will still perform at least as good as the historical Fw 187 (much better power at altitude for the British machine), and it will be easier to upgrade with Merlins rather than it was (not) the case with Whirly.
Hauling 12 .303s at 375 mph in 1940 (or at 340 mph in 1938) is a far better thing than hauling 8 .303s at 315 mph. Having 50% extra firepower is not a trick, nor is the extra speed. Once people start add protection for both pilot and fuel, a 2-engined fighter will have better time wrt. loss of performance (both speed and RoC). Replacing MGs with cannons is less tricky on a 2-engined fighter.
British also have wherewithal to produce and field 2-engined fighters along the 1-engined fighters.
Just pointing out that time was a factor, especially for some people that want to cut aircraft types and combine production. It took a while and with hindsight we can see that the P-47 could do most of the things the P-38 could. BUT without hindsight it is not so obvious and it requires adding another R-2800 factory to make the engines (and changing P-38 production to P-47), also requires changes to the P-47 earlier.A fighter that fits the description can be in production by 1938. The one with R-2800 can be in production by 1941?
USAAC was requiring new fighters pronto in the late 1930s (one of big reasons what they went all-out with P-40 and why XP-39 lost the turbo), the P-47 as we know it was not even in drawing phase in 1938.
Which is more than a little late.
The Lockheed design team was working though the summer of 1937, the Army issued a contract ($163,000) for the XP-38 prototype on June 23rd 1937. Construction started in the summer of 1938 (?). A bit late to change from a twin engine design to a single engine airframe
The Engines in the 314 Clipper were rated at 1500hp/2400rpm for take-off and 1200hp/2100rpm at 5,000ft 'Normal/max continuous'
Questions are if GE can supply a turbo for the R-2600 at this time (The B-1 turbo used on the XP-38 might have been too small leading to needing two?) and if the R-2600 engine would cool at hi-altitude at power levels.
Drag of one big radial engine. The R-2600 was about 54-55 in diameter, it was almost identical to the R-3350, just two less cylinders on on each row.
The R-2800 had about 92% of the frontal area of the R-2600 which helps explain (not the only reason) the lack of R-2600 powered fighter designs.
We are scrambling times line here. In 1938 an R-1830 was a 1050hp engine for take-off. It wouldn't get to 1200hp until mid 1940 in production (and needed 100 octane fuel)
Hanging 37mm cannon under each wing wasn't going to to work.
Well, it is questionable if the six .50s were a good idea for R-1830s and V-1710s of 1942-43 let alone for 1938-40
Problems with the twin Kestrel is that the Kestrel is over 100lbs lighter than the Peregrine. Change to the Merlins is not impossible but is more difficult.
Problem is not helped by the extra 30-50 sq ft of wing if the wing is not strong enough to do what you want. If you want good performance with a pair of 745hp engines at 14,000ft
you have to keep the wing structure light. Changing from 970-980lb engines to 1430-1450lb engines (and coolant/oil coolers, ect) AND maintaining the strength requirements ( Mosquitos were not built to fighter "G" Loads) requires beefing up the wings (and more?) and that requires making a bunch of stress calculations.
FW 187 has about 10% less power than the Kestrel. Depends on who (and what) you believe about RAM pressure and exhaust thrust.
Just pointing out that time was a factor, especially for some people that want to cut aircraft types and combine production. It took a while and with hindsight we can see that the P-47 could do most of the things the P-38 could. BUT without hindsight it is not so obvious and it requires adding another R-2800 factory to make the engines (and changing P-38 production to P-47), also requires changes to the P-47 earlier.