Prop Aircraft conversions into Jets

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SirCoutin

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I've seen a few of these, examples being the Yak-15/Jumo Hybrids, the P-57 Airacobra, SAAB's J21R etc..

What others have you guys found across your researches?
 
We touched on this topic in another thread that was about piston to turbo-prop conversions.
The ultimate was the Chase/Fairchild C-123 which was originally built as an assault glider, then converted to a pair of piston engines, then booster jets added (the most widely used variant), Taiwan experimented with a turbo-prop conversion and finally the USAF test flew a pure jet version with a total of 4 jets in a pair of under-wing nacelles. C-123 was the only airplane to fly as a glider, piston, piston plus jets, pure jet and turboprop power.

Ted Smith built a single jet conversion to his mid-wing Aerostar light-twin (piston engines).

Beechcraft converted a King Air light-twin from turboprops to over-wing jets.
King Air was in turn a turboprop conversion of their piston-powered Queenaire. Queenaires may have only sold in small numbers, but more turbo-prop King Airs have sold than all other light twin turboprops combined.
 
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Bell's nomenclature can be confusing because they used the P-59 designation for two totally different concepts. This was likely wartime maskirovka intended to confuse Nazis.
The first P-59 was a still-born, piston-powered fighter with a single propeller spinning between a pair of tail booms.
OTOH Bell only re-used the number when they started work on their first jet. Bell's P-59A Airacomet was a totally new fighter based upon a pair of early British jet engines. Maskirovka included installing a fake propeller during transit to Muroc Dry Lake Bed (now Edwards Air Force Base).

Tucker's XP-57 light fighter proposal never made it off the drawing board. While it shared a similar mid-engine configuration with Bell's P-39 Airacobra, they shared no common parts.
 
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Oops, sorry! Anyways, were there any other WW2/Late 40s designs to convert WW2 era prop aircraft into jets?
 
Apparently there was a XP-55 Ascender jet modification? I haven't seen any pictures of it though
 
SirCoutin said:
Still, are there any drafts that have shown up?
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I have seen nothing in our Curtiss Wright-St. Louis folders, either on paper or in images. The reality was the XP-55 was a dead end approach to a fighter that the USAAF was not pursuing and a jet engine wasn't going to change that.

We have wind tunnel model photos and a side profile drawing for the proposed cargo transport (P-274) using XP-55 design elements - I have seen artwork on the C-W St. Louis internal magazine for a jet powered version of that but other than the artwork, no drawings, documents or images.

Enjoy the Day! Mark
 

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  1. Northrop YB-35 into YB-49
  2. Douglas XB-42 into XB-43
. . . and I assume you mean from prop to "all jet", otherwise C-123 (as riggerrob has already mentioned) and B-36, and I think maybe a couple more that are slipping my mind right now. Edited to add more "prop to prop+jet" conversions:
  • Lockheed P-2 Neptune
  • Boeing KC-97
  • Avro Shackleton
 
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IIRC, the Bristol Brabazon Mk2 would replace #1's piston-engines with turbo-props, probably would have evolved to mix like the big US bomber with its combo of 'turning & burning'...

But, never got off the drawing board...
 
SirCoutin said:
Was the P-47 jet conversion actually real or is it something fictional?
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Fictional. Republic was designing the P-84 Thunderjet as their jet fighter entry.

Another sort of conversion was North American's original XP-86 "jet Mustang" design. It used a new fuselage mated to P-51D wings and tail surfaces. The USN picked it up as the FJ Fury

1649829299501.png
 
SirCoutin said:
To be clear, this is fake? https://www.militaryfactory.com/aircraft/detail.php?aircraft_id=1537
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Fake. There are clear engineering issues that would arrise with this design. First, the jet engine would be assumed to be ahead of the cockpit slightly aft of the original radial engine. This would require a very long tail pipe for the engine resulting in a loss of thrust. It would also require a redesign on the rear half of the fuselage to widen it to take this exhaust.
The cockpit would be another issue. Would there be room beneath it for the exhaust? How would it be kept insulated from the heat generated by that exhaust?
Then there are serious CG issues. You've removed the turbosupercharger and all associated ductwork, put a much lighter turbojet in the plane instead of a piston engine, and made other changes as well, such as--at least in the picture--added in a bunch of weight forward in armament and ammunition while removing this (I assume) from the wings.
Then there's the fuel issue. Turbojets consume far more fuel than piston engines do. Where do you cram all that fuel? That could lead to more serious CG issues as well...

Hence, why Republic chose to design the P-84 Thunderjet from scratch rather than do some lash up converting an existing design into a jet like the Russians chose to do early on.

If, as the narrative given, the J35 axial turbojet is used instead of a J31, then the whole exercise is a waste of time. The J35 wasn't available prior to WW 2 ending and post war there is no rush involved in getting a jet fighter into service. The USAF would have no reason to want to make some sort of lash up, half-solution out of an older piston engine fighter over designing a proper and clean design from scratch, especially when they already had these well advanced in 1945. Totally fake.
 
T. A. Gardner said:
SirCoutin said:
Was the P-47 jet conversion actually real or is it something fictional?
Click to expand...
Fictional. Republic was designing the P-84 Thunderjet as their jet fighter entry.

Another sort of conversion was North American's original XP-86 "jet Mustang" design. It used a new fuselage mated to P-51D wings and tail surfaces. The USN picked it up as the FJ Fury

View attachment 676818
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Actually, they are much closer to P-51H wings although they added the wing root extensions. The tailplane were also much bigger that the P-51D, even bigger than the P-51H. The fin/rudder is the same size as the F-82 fin/rudder. Another aircraft that used this wing was the T-2 Buckeye.
The image below was gleaned from this forum somewhere
 

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I.Ae. 30 Ñancú variants, including two jet designs
 

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Another plane where the designers mated a new fuselage to existing wings and tail surfaces is the Supermarine Attacker.

1649944029338.png

This time, Supermarine mated the wings and tail assemblies of the piston engine Spiteful to a new fuselage. They even left the jet a tail dragger... Early in it's development it was often referred to as the "Jet Spiteful."

Like the Jet Mustang, the Attacker had very pedestrian performance for a jet aircraft.
 

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