What if: a de Havilland single seat, single piston engine fighter for World War II

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I know that we talked about this plane maybe using wing leading edge radiators, but I do think a ventral radiator might be better for overall packaging and maybe even CG. I've also given some thought to this being the basis of a twin aircraft (like the F-82) as a very long range escort fighter/recon aircraft, or heavy interceptor/night fighter. That being said, I'm not an engineer or designer. In terms of aero the deficits and strengths do cancel each other out IMO. It's just a matter of which is actually better for packaging.

As for armament, if we're talking about using the Vampire's wing plan form and profile, would wing mounted 6-8x.50 MGs with 300 (min) or 400 (preferable) RPG, or 4x20mm cannons with 150 or 200 rpg?
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Some possible food for thought for design influence could be the Mosquito and Hornet (in spite of being twin engine) and maybe this Airspeed project (Airspeed was a division of de Havilland at the time). Note, though, this plane was designed around the Napier Sabre engine, and is quite a bit bigger than a design that DH would likely come up with for a single seater powered by a single Merlin. In fact, in terms of OA length and wingspan, it's not a ton smaller than a Hornet.

I'll open this up initially for the forum to chime in with what their ideas on what this could've been like, though I do have to provide my broad idea for it. I do imagine at the basic, fundamental level, it's probably be like half a Hornet (half the size, half the power), and powered by at least a Merlin 60 series engine with room to go up to the Merlin 100 series. I'm also sort of inspired by the original Hornet design brief of two Merlin 60 series engines, and a weight of 15,000 lbs clean combat.

Outside of that, it'll be up to you to give feedback on what you might expect to see.
When would they do this and what would they accomplish?

Would a wooden fighter plane equal or exceed the performance of a Spitfire or of an Fw190? The Hornet took advantage of the experience designing and building Mosquitos. Were the British in need of a new fighter aircraft? Do we replace Spitfires or Typhoons or Hurricanes?
De havilland has very little history of single piston engined monoplane aircraft. There is the de Havilland Don introduced in 1938.


Scaling up to something with a Merlin and single seat might be a stretch.
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Swap in a Merlin and single seat and see what you get.

A disaster waiting to happen.
  • Length: 37 ft 4 in (11.38 m)
  • Wingspan: 47 ft 6 in (14.48 m)
  • Height: 9 ft 5 in (2.87 m)
  • Wing area: 304 sq ft (28.2 m2)
  • Empty weight: 5,050 lb (2,291 kg)
  • Gross weight: 6,530 lb(2,962 kg)
  • Maximum speed: 189 mph
Yep, makes a Typhoon look small.
It is not built to take a Merlin, just watch the fuselage twist as you hit the throttle.
It is not built to take fighter speeds. Assuming you could manage to get this contraption up to 285mph in theory, a what actual speed do the wings fall off?
50% increase in speed means the forces on the wings go up by 125%. Not a total of 125% but an increase of 125% above what the wings were dealing with at 190mph.

yes you could fix this and you could fix that and you could also fit the shakes. By the time you are done you have spent more time than if you had just designed a new airplane.
See De Havilland DH93 Don

for a pair of photos that have people in them to give some scale, this thing was huge.
Thinking about the wing leading edge radiators, I did read on this forum that Hawker claimed zero drag on the Tempest I and maybe the Fury I. I, like the person who made the comment, find it a bit far fetched. If we look at those radiators compared to say the Mosquito or Hornet, as far as trying to get the drag limiting Meredith effect, the Tempest I/Fury I have small intakes, the radiators themselves seem to be aligned with the wing leading edges, and there doesn't seem to be much room for expansion of the air going into or coming out of the radiators, which is what's needed to get something out of the effect.

Also, the Mosquito and Hornet, being twin engined, ran larger radiators (one per engine), and the radiators and their intake/exhaust seem to stick out a lot further ahead of the front wing spar (where the assembly attaches). Of course, being twin engined and having thicker wings than most single seaters, the Mosquito and Hornet do benefit better than I think a single engine aircraft would. You still can get drag reduction though reduced frontal area, but I don't think that such an arrangement is great for trying to exploit the Meredith effect to try and reduce/offset aero drag.

Not to mention packaging. On a single engine fighter, the main landing gear is in the wings, and is also usually a popular place to put fuel tanks. To run leading edge radiators, you'd need to have the front spar close to the wing leading edge, and that usually means having the landing gear mounted behind it. Which means that the gear bay takes up space for a wing mounted fuel tank. One solution could be have the leading section of the gear bay (ahead of spar mounting) form a false spar.

Another thing that I consider maybe both a blessing and a curse for the leading edge radiators is that you'll end up with two of them. That could be a bit of a blessing as it could maybe give redundancy (like on the Me-109G's wing mounted radiators where if one was damaged, you could divert all coolant flow to the good radiator), but you also have twice the cooling matrix, twice the plumbing, and the other aforementioned packaging issues and potential limitations.

So I guess this is sort of maybe horses for courses. Maybe for a single engine fighter a ventral Meredith radiator is maybe the best all round packaging deal. While on a twin, Mosquito and Hornet type radiators probably work best.
I don't gave the diagrams available at the moment, but there are considerable differences in air pressure points on an airframe as it moves through the air.

The air at the leading edge of a wing is being compressed and "divided" as the airflow is forced over and under the wing.
The airflow along the bottom of the fuselage will have a different behavior.

If you look at the P-51's radiator, the intake is extended away from the fuselage just enough to take advantage of air that has not been fully disturbed.
I do wonder what effect a Spitfire or Mosquito type supercharger intake would have on airflow into a ventral radiator intake like a Mustang's?

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