Aircraft engines. Swapping and upgrading.

[SinUnNombre]

I may still be running off a fair amount of the holiday cheer, but how about a radial engine in a P-39?

I'm thinking one of the more tightly cowelled radials to keep the inevitable mid fuselage bulge to a minimum.

Imagine if the Soviets played around with the idea of sticking a Svetsov radial in some of their Airacobra's.

If you look at pictures of the Airacobra prototype prior to removal of the supercharger, it was a notably bulged afair in that area of the fuselage, so perhaps a suitably compact radial could go into the area with not much more modifications than were required to house the abandoned supercharger.

Maybe you could work that into a Centaurus powered P-63 on a slightly later timescale.

Cool idea. One problem though. Cooling. Most, if not all radial engines are air-cooled. Hence the open-fronted cowlings. The inline Allison in the P-39 in water-cooled, like your car. How would you channel the air around the engine for proper cooling? But if you could make a water-cooled radial, then it would work. But then you run into the issues of weight and sheer room to package everything. Just a thought...

Jon

I think if you put the supercharger air scoops that the prototype had back into the design, then you would have the means to both aerodynamically fair it in and provide air to cool it.

Could be wrong about that though

I just want to say first off, I'm not trying to shoot down your idea or anything. I'd love to see the P-39 with an Ash-82(Lagg-5) radial on the front end. For a point of reference, McGreig's radial Spitfire in the Workbench forum used this engine.

The only problem, other than the weight that is, is being able to get enough air in to cool it then get that air back out easily and efficiently. Look at aircraft designed for radials. They have the big opening in the front to get the air in. That opening is as big around as the engine itself to cool as much surface area at a time. Then they have those big flaps along the back of the cowl. The air forces those flaps open as a way back out. Even better, look at the M18 Hellcat tank detsroyer, which was powered by a radial engine. It had a huge fan mounted to the front to help move air in through the open top.

Now, if you could design a water-cooled radial, along with some wing root radiators, your cooling problems would be solved. The only problem left, and its augmented by the cooling system, is weight. The radiators, the hoses and tubes, the coolant itself, all weigh the plane down. A radial isn't light to begin with, then you just put more on top of it. It's a vicious circle, isn't it?

Jon

[jcf]

I may still be running off a fair amount of the holiday cheer, but how about a radial engine in a P-39?

I'm thinking one of the more tightly cowelled radials to keep the inevitable mid fuselage bulge to a minimum.

Imagine if the Soviets played around with the idea of sticking a Svetsov radial in some of their Airacobra's.

If you look at pictures of the Airacobra prototype prior to removal of the supercharger, it was a notably bulged afair in that area of the fuselage, so perhaps a suitably compact radial could go into the area with not much more modifications than were required to house the abandoned supercharger.

Maybe you could work that into a Centaurus powered P-63 on a slightly later timescale.

The scoops were for the turbo-supercharger (left-side) and the oil cooler(right-side). The scoops were add-ons and the fuselage structure itself was not bulged. The installations created a great amount of drag and were removed after wind-tunnel testing, the oil cooler intakes were relocated to the wing leading edge along with the radiator intakes. Other changes include a reduced height cockpit enclosure, relocation of the carburetor scoop to the top of the fuselage behind the cockpit and a shortened wingspan.

BTW all models of the P-39 and P-63 were supercharged, a centrifugal supercharger was a standard fit on the Allison V-1710. What was removed from the XP-39 was a separate exhaust driven turbo-supercharger. The P-63 used a secondary two-stage supercharger driven by an accessory shaft from the engine.

Piaggio built a fighter with an amidships buried radial, the P.119 and she was a bit on the chunky side:





A radial powered P-39/P-63 is pretty much a non-starter as the airframes are both very narrow in cross-section, it would look like a snake that just swallowed a pig.
So, if you did build one it would have to be called the...







Airaconda. :dum:  :dum:

Jon

[GTX]

A radial powered P-39/P-63 is pretty much a non-starter as the airframes are both very narrow in cross-section, it would look like a snake that just swallowed a pig.

What if one had the radial somewhat exposed - say somewhat similar arrangement to the Rhein-Flugzeugbau GmbH (RFB) Fantrainer - please note I know this aircraft didn't use a radial and that it is actually the fan in the shroud, but for illustrative purposes:





As for other pusher radial applications, don't forget the Kyūshū J7W Shinden planned on using a rear-mounted 2,130 HP Mitsubishi Ha.43-42 18-cylinder radial engine as well, so it isn't inconceivable that ducting could get sufficient cooling air to such an engine:



Regards,

Greg

[kitnut617]

Also the XB-35 and B-36 also had aircooled radials buried in the wings fed by ducting.

[Chap]

how is this, the DH-88 Comet looks a lot like a gypsi powered 262, could be a good platform to start with 

Got me thinking; if only Airfix brought theirs back out.

[B777LR]

how is this, the DH-88 Comet looks a lot like a gypsi powered 262, could be a good platform to start with 

Got me thinking; if only Airfix brought theirs back out.

Oh yes, and add a clear nose for a bombardier (like early mosquitoes), and fit rockets and a torpedo!  

[jcf]

AM-35A
60 degree V-12
Takeoff power: 1,350 hp
Weight: 830 kg (1,829 lbs)
Length: 2,402mm (94.57 in)
Width: 866mm (34.09 in)
Height: 1,089mm (42.87 in)

AM-38
60 degree V-12
Takeoff power: 1,600 hp @ 2,150 rpm
Weight: 860 kg (1,895 lbs)
Length: 2,289mm (90.12 in)
Width: 875mm (34.45 in)
Height: 1,082mm (42.60 in)

AM-38F
60 degree V-12
Takeoff power: 1,700 hp @ 2,350 rpm
Weight: 880 kg (1,940 lbs)
Length: 2,287mm (90.04 in)
Width: 878mm (34.57 in)
Height: 1,084mm (42.68 in)

AM-39B
Takeoff power: 1,750 hp @ 2,350 rpm
Weight: 1,040 kg (2,292 lbs)
Length: 2,415mm (95.08 in)
Width: 890mm (35.04 in)
Height: 1,142mm (44.96 in)

AM-42
60 degree V-12
Takeoff power: 2,000 hp @ 2,500 rpm
Weight: 1,012 kg (2,230 lbs)
Length: 2,290mm (90.16 in)
Width: 875mm (34.45 in)
Height: 1,153mm (45.39 in)

VK-107A
60 degree V-12
Takeoff power: 1,650 hp @ 3,200 rpm
Weight: 769 kg (1,695 lbs)
Length: 2,166 mm (85.28 in)
Width: 867 mm (34.13 in)
Height: 962 mm (37.87 in)

M11-FM
5 cyl, single row radial
Takeoff power: 111 hp @ 1,800 rpm
Weight: 172 kg (379 lbs)
Length: 1,010 mm (39.76 in)
Diameter: 1,075 mm (42.32 in)

M82
14 cyl, dual row radial
Takeoff power: 1,700 hp @ 2,400 rpm
Weight: 850 kg (1,873 lbs)
Length: 2,005 mm (78.94 in)
Diameter: 1,260 mm (49.61in)

Ash-82F
14 cyl, dual row radial
Takeoff power: 1,850 hp @ 2,500 rpm
Weight: 938 kg (2,067 lbs)
Length: 2,005 mm (78.94 in)
Diameter: 1,260 mm (49.61in)

Have fun with your engine swaps, the Sovs had some big ol' lumps.

Jon

[brewerjerry]

 [/quote]
Is there any mention of this Whirlwind II in Tony Buttler "british secret projects 1935-1950" ?    
[/quote]

Hi
   Nothing on the Whirlwind II, in 'secret projects'
   Only the original P9 with twin fin tail and R-R Kestrels (1936) is mentioned.
   However on page 42 is two drawings of a whirlwind 'type',  options as with either griffons or merlins engines to F6/39, fitted with either 'coventional tractor type' or with 'pusher' engines, ( this design is pre welkin ).
   Of interest maybe it mentions the welkin would have originally had griffon engines, another what if..
   Whirlwind II is only in binghams book, and the research files at the NA at Kew London.
    Cheers
       Jerry
   

[GTX]

It was a real pity the Napier Sabre was never able to be made to work for the Typhoon:



Regards,

Greg

[Maverick]

Neat looking Tiffie Greg, but wasn't the Sabre the standard powerplant (ie Inline not radial) for the Typhoon and Tempest V/VI??

[GTX]

No - your mistaken.  After the Sabre failed, Hawker decided to use air cooled Pratt & Whitney R-2800 radials built under licence

Regards,

Greg

[sequoiaranger]

Ever since I heard about the Rolls-Royce "Exe" engine, a 24-cylinder aero engine somewhat like the doomed "Vulture" engine that initially powered the Avro Manchester and the Hawker Tornado (incidentally, there were never any problems with the Tornado's Vulture that plagued the Manchesters'), I have wanted to imagine an aircraft using it. I have always liked the Hawker Tornado look of the double row of exhausts (Vulture engine), and was going to apply that look (see pic below) to an upcoming Hawker Henley whif. Supposedly the Exe engine produced considerably more horsepower than a Merlin, and supposedly the Exe was destined for the Fairey Barracuda, but the Merlin was supplied instead. From what I can tell, the Exe project was shelved, not for lack of merit, but, as as the war began, a necessary culling of engine projects that took effort away from "needed" projects.  Hmmm.

I came upon some new (to me) information about the Exe, that it was an inline AIR-COOLED engine of sleeve-valve configuration, and that the Fairey Battle test-bed gave no problems and was a favorite "hack" for Rolls-Royce factory officials.

I have wondered what the cowl arrangement would have looked like. On one hand, this is an INLINE engine (in an "X" configuration) but AIR-COOLED. My book says "forced-air cooling", whatever that means. I can see that an air-cooled engine on a stand in the factory needs "forced-air", but one would think that, like air-cooled radials, that the motion of the plane would send "forced air" past the engine. Air-cooled radials have, eliminating the four-row monsters at the end of the war, at best TWO rows of cylinders that need cooling, and the rear row of cylinders is positioned between the front-row cylinders so frontal air hits both rows nearly simultaneously.

The "Exe" engine has SIX rows of cylinders, and in each row the cylinders are right behind one another. Seems like asking for a cooling problem, as in a large air chamber like an air-cooled radial cowl the air heated from the first row passes over the second row, etc., until each progressive row is "starved" of cool air and would likely overheat. Seems like the cowl would have to be somewhat like a radial-engine cowl with lots of open space for the air to enter, then MAYBE multiple chambers, or even "intake manifolds" to direct the incoming cool air to each cylinder independently. Then, like air-cooled radials, the heated air has to be vented.

I wish I knew what the test-bed Fairey Battle looked like (anyone know?), but is my crude illustration below is a possibility?? That is, a wide frontal opening chambered into four intakes for each of the rows, presumably with internal manifold to direct the air, then flaps a ways back on the fuselage to let the now-hot air out??

Comments are always welcome and appreciated.

[jcf]

Battle K9222, Exe testbed. The Exe was rated at 1,150 hp for takeoff.

The cooling path for a production Exe equipped aircraft could have resembled the reverse flow setup as used successfully on the
De Havilland DH 91 Albatross, and not quite so successfully on the Armstrong-Whitworth Whitley II used as a test bed for the
21-cylinder radial Armstrong-Siddeley Deerhound engine.

Jon

[sequoiaranger]

>Battle K9222, Exe testbed.<

WOWZA! I figured you, with your extensive research "powers", might come up with something. Thanks. A WHOLE BUNCH!

>The cooling path for a production Exe equipped aircraft could have resembled the reverse flow setup as used successfully on the De Havilland DH 91 Albatross, and not quite so successfully on the Armstrong-Whitworth Whitley II used as a test bed for the 21-cylinder radial Armstrong-Siddeley Deerhound engine.<

Dunno about those.

I had to smirk when I saw the "periscope" carburetor intakes atop the fuselage (I assume that's what they are). And the very simple pyramidal air outlets on either side (containing the two exhaust tubes per side, as well?). The fact that the one large scoop on the bottom seemed to suffice will "allow" me to use the Tempest chin radiator for the Henley whif as I had planned before I found out the Exe was air-cooled. Now I can rig up some air outlets similar to radial-engine cowlings, and won't have to come up with an "original" new type of cowl frontispiece. That's a great relief. Some nice brass screening at the scoop intake will relieve me of concocting some weird interior plumbing or air manifolds.

>The Exe was rated at 1,150 hp for takeoff.< 

Yes. I believe that was when the contemporary Merlin was putting out only 940 HP. Considering how the Merlin power escalated to nearly 2,000 HP with refinements by 1945, I figure the Exe could certainly do something similar (keep its power output about 20% above the Merlin), or at least be competitive.

Once again, thanks for the "1,000-words of research" (a picture).

[jcf]

The cooling air for the 12-cylinder inverted V engines of the Dh 91 entered through inlets on the wing leading edge, was ducted forward over the cylinders and exited beneath the engines.

The Deerhound (I'll scan photos later) installation used a large scoop beneath the engine.

Jon