Airacobra, Kingcobra, and Airabonita Ideas and Inspirations

[elmayerle]

According to both Birch Matthews' Cobra!: The Bell Aircraft Corporation 1934-1946 and
Pelletier's Bell Aircraft since 1935, the performance of the sole bubble-top, 1,425hp
V-1710-109 engined P-63D was roughly identical to that of the P-51D. So as the P-63D was no
improvement on the performance of the, all ready in mass production, P-51D, the USAAF
passed on ordering it in quantity.

This may be what Donny was thinking of.

An interesting unbuilt proposal was the XP-63B with 1,400hp Packard Merlin V-1650-5.

The obvious thought that comes to mind is crossing the XP-61B and the P-63D.

[tsrjoe]

how about an Airacobra derived Soviet VTO. ...

http://www.unicraft.biz/on/kit1/kit1.htm

[dy031101]

Indeed P-63 at its best offers no improvement over the P-51.  And no, what makes the Mustang shine (such as, first and foremost, range) isn't lost to me.

Floatplane fighter or racer derivatives?

[GTX_Admin]

Well there were real world racers...But not as snazzy looking as that one!

[Weaver]

Which all kind of makes the point: "only as good as a P-51" is hardly a condemnation given that the P-51 was such an exemplary machine. That means that if you didn't have P-51s, you'd be as well off with P-63s! The only reason the US didn't buy the P-63 in numbers was that they simply didn't need it, not because there was anything wrong with it.

Much the same could be said of the Martin-Baker MB.5, which was, by all accounts, a superb fighter, but there was no point complicating matters with another type when Tempests and Spitfires were pouring off the lines, the end of the war was in sight, and jets were just around the corner. Yet no-one tries to use the RAF's rejection of the MB.5 as "proof" that it was inferior in the way that some do with the P-63...

Anyway, Airacobra ideas. I have a few stashed away with the intention of doing some or all of these at some point:

1. Airacobra Autogiro. Cockpit moved forwards, pylon in original cockpit position with rotor that be clutched to the engine for start up. Clipped wings with gun pods on the ends.

2. Twin turboprop Aircobra. Co-axial, counter-rotating props, one small turbine in the nose bay, the other in the engine bay. Front engine has intake and exhaust on the same side, rear engine has them both on the opposite side: this is the only way to stop the rear intake from breathing the front engine's exhaust AND keep the exhaust thrust symetrical. Needless to say, the side doors are abandoned!

3. Scaleorama a 1/48th Airacobra to 1/72nd to make a big turboprop strike fighter that takes the same place in an alternative timeline that the Wyvern takes in the real one. This is part of a half-formed idea for Southsea Aircraft Ltd: a ficticious but hauntingly familiar company based in Dorset who's products included a high-winged STOL Army liason aircraft, a twin-engined single-seat fighter, a turboprop strike fighter for the Navy, and an awful lot of helicopters...

BTW, that floatplane P-63 is gorgeous! 

[dy031101]

Which all kind of makes the point: "only as good as a P-51" is hardly a condemnation given that the P-51 was such an exemplary machine. That means that if you didn't have P-51s, you'd be as well off with P-63s!

To be fair though, then the Allies would have needed something else to escort the Flying Fortresses all the way on bombing missions, to say the least (which might have hastened the advent of the P-47N?).

P-63 is still one of my favourite WWII fighters, nonetheless.

[dy031101]

P-63D with new wings.  So where did I take the wings from...... 

[elmayerle]

P-63D with new wings.  So where did I take the wings from...... 

A P-47N, obviously.

[The Big Gimper]

Tempest?

[finsrin]

Weaver's  #2 and #3 concepts in reply 29 are what I would like to see in Styrene.  Cool stuff 
Bill

[dy031101]

Now whether having a better supercharger would have made the P-39 a better mid-to-high altitude
fighter is another issue, as you'd still have the relatively small and thick wing attached to an
aircraft that was intended more as a bomber interceptor than a pure fighter.

Does the XFL-1/2 use the kind of wing?  Or is the Airabonita more of a general-purpose fighter?

[apophenia]

Does the XFL-1/2 use the kind of wing?  Or is the Airabonita more of a general-purpose fighter?

Airabonita wing was essentially that of the P-39 with the main gear moved to the front spar and twin radiators replacing the Airacobra's buried rads.

[dy031101]

A P-47N, obviously.

elmayerle got it right.  Although I was wondering if I was onto something......

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I want to do something to the XFL...... but don't know what to do.

In the end, just nose guns (don't know what apophenia puts in his, but mine is as the P-39Q; Wikipedia claims that production Airabonita can be so equipped), four-blade propeller, and elimination of arrestor hook (which apophenia also did with his).  I didn't bother with wing gun pods because I also heard that many P-39Q pilots chose to get rid of those to save weight.

I assume a Merlin-inspired supercharger wouldn't be externally-visible?

[Weaver]

Since the P-39 had a large wheel bay in the bottom of the nose, you've got to wonder what the Airabonita had there? I wonder if there was enough space for a third 0.50 cal MG?

[apophenia]

Since the P-39 had a large wheel bay in the bottom of the nose, you've got to wonder what the Airabonita had there? I wonder if there was enough space for a third 0.50 cal MG?

Good question. With some revision of that lower 'chassis' structure, I'm sure that you'd have room for that 0.50 in the centre and another pair on either side of the lower fuselage (P-51A-style).

[jcf]

Airabonita wing had increased span, chord and dihedral; the fuselage was shortened; cockpit raised
and vertical tail surfaces revised in shape. It wasn't just a tail-dragger Airacobra.
 

The 37mm gun was intended as main armament.

Vought won the "contest" with what became the Corsair.

The XP-39E was powered by the two-stage Allison V-1710-E9 (similar to the engine that powered the P-63)
and the fuselage was 20 inches longer. So, if when speaking of a 'Merlin-inspired' supercharger one means
the two-stage/two-speed type as equipped the Packard-Merlin V-1650, then yeah, it'll be visible as you
couldn't fit it into the P-39 airframe and retain a useful load, a stretch would be sensible. Yes, the Cobra I & II
air racers had P-63 engine shoe-horned into P-39 fuselages, however these aircraft were stripped to the bone,
and weight/balance issues that would be critical in a service aircraft, were just part of the fun.

A note on terminology, there was and is no 'Merlin' supercharger per se, the various engine driven centrifugal
superchargers used on R-R engines were based on what had become fairly standard supercharger design
principles that had been worked out by engineers and designers in several countries. BTW the French stuck with
a less efficient, and more complicated, home-grown design for the Hispano-Suiza engines after just about
everyone else had adopted simpler, cleaner designs.

Also Allison, if GM had been willing to spend the money to hire enough designers and pay the development cost,
could have come up with a better two-stage design than the one use don the P-63 and P-82 engines, Hell, they
could have adopted elements of Pratt & Whitney's two-stage designs that worked so well on their radials.

 

[RussC]

Great exploration of this type. I once toyed the idea of the Russians license copying the P-39 fuselage onto a Parabola wing with rudderlets at the tips, but built my Revell 144th cobra stock and standard like a wuss', -----made up some karma by building the car doors open and a instrument panel detail level that would rival a 1/48th kit. The original kit had a look-through from the cockpit down through the front gear doors!

[Weaver]

Since the P-39 had a large wheel bay in the bottom of the nose, you've got to wonder what the Airabonita had there? I wonder if there was enough space for a third 0.50 cal MG?

Good question. With some revision of that lower 'chassis' structure, I'm sure that you'd have room for that 0.50 in the centre and another pair on either side of the lower fuselage (P-51A-style).

Not sure about that: the P-39 was built around a very strong structural "keel box" that had to be full-width to keep the engine and gearbox aligned, so there was room for a full-width gun bay above it, but nothing to either side of it. The nosewheel bay was in the middle of it.

Good cutaway:



From here: http://www.fiddlersgreen.net/aircraft/Bell-P39-Airacobra/IMAGES/Bell-P-39-Airacobra-Cutaway.jpg

[dy031101]

The XP-39E was powered by the two-stage Allison V-1710-E9 (similar to the engine that powered the P-63)
and the fuselage was 20 inches longer. So, if when speaking of a 'Merlin-inspired' supercharger one means
the two-stage/two-speed type as equipped the Packard-Merlin V-1650, then yeah, it'll be visible as you
couldn't fit it into the P-39 airframe and retain a useful load, a stretch would be sensible.

If I'm using XFL-1 as a base, would the new engine alone be enough to "make it good"?

IIRC, XP-39E was unsuccessful because other aerodynamic changes made it inferior at lower altitudes to stock P-39s.

[GTX_Admin]

I wonder...a dedicated tank buster AP-39...ancestor of the A-10/competitor to the Il-2?

[jcf]

If re-engining the XFL-1, why not go all in and make it an air-cooled version of the V-1710?
Air-cooled and inverted air-cooled versions were made of the Liberty engine, so why not the V-1710?

A compact two-speed/single-stage blower would probably give the required low to mid-altitude
performance required of a fleet air defense fighter.

 

[dy031101]

If re-engining the XFL-1, why not go all in and make it an air-cooled version of the V-1710?

Because I don't know how to make visual representations thereof 



Land-based FL-1 with stretched fuselage to accommodate two-stage-supercharged V-1710.

Is "Model 15" already occupied within the Bell company designation?

(Wondering if I can use it as a what-if designation for a land-based XFL-1......)

EDIT: As per jcf's suggestion below, the pics are now named "Model17".

[jcf]

Model 15 = P-39D

7,8,9 and 17 - 25 inclusive are not on the list in Pelletier's Bell Aircraft since 1935.
Now that I've said that, Stephane will probably be along with the missing numbers. 

Air-cooling means you need air-intakes and exhausts, so eliminate the radiator housings
under the wings and add some inlets and outlets on the fuselage, perhaps something
resembling the side-scoops of the XP-39.

The Piaggio P.119 had an air-cooled radial buried mid-fuselage, so perhaps look at it
for inspiration on your vents.
http://www.airwar.ru/enc/fww2/p119.html



 

[elmayerle]

If re-engining the XFL-1, why not go all in and make it an air-cooled version of the V-1710?
Air-cooled and inverted air-cooled versions were made of the Liberty engine, so why not the V-1710?

A compact two-speed/single-stage blower would probably give the required low to mid-altitude
performance required of a fleet air defense fighter.

The engine technology advances from the Liberty to the V1710 would make an air-cooled version of the V1710 much more difficult than air-cooled versions of the Liberty.  With the engine buried like that, it would take some interesting cooling scoops, cooling air exhaust ducts, and engine baffling to properly cool an air-cooled engine.

dy, IMHO using a R2800 would yield just as portly an airframe as the Piaggio.

[dy031101]

dy, IMHO using a R2800 would yield just as portly an airframe as the Piaggio.

Might there have been a radial with a better balance of size and output for the "air-cooled" Airabonita?  Or would the R-2800 have been perfectly good anyway?

Nevertheless, I tried an intellectual exercise with R-2800.



What do you think?