Aircraft combies that have propellor and jet engines for power.

[PR19_Kit]

Yes, that's what I meant, not turbojet, don't know where my head was.

The -123 DID fly in an all jet configuration. It had dual pods under the wings like a B-47, but I suspect not the same engines or it would have been faster than a Sabre!

[perttime]

There must be some reason it never became common... experimentals are the only ones that come to my mind.

Heinkel used two or three He 112 prototypes for prop / rocket experiments. It flew. There's a couple of short videos at:
http://www.firstjetpilot.com/archive.html

More recently McDonnell tried if they could extend the range of a jet fighter by installing a turbo-prop in the nose of an XF-88 Voodoo prototype:
http://en.wikipedia.org/wiki/McDonnell_XF-88_Voodoo



Perhaps a bit out of scope for this thread... Yakovlev's Yak-15 jet was essentially a re-engined Yak-3 prop fighter. Like SAAB's 21R jet was a re-engined SAAB 21 prop fighter.

[PR19_Kit]

Yet another piccie of the XH-88H without the turbo-prop running! 

I have NEVER seen a pic with the prop rotating, either the engine didn't work or they were using STUPIDLY fast shutter speeds......

[Old Wombat]

The prop's feathered, Kit, so it ain't shutter speed - the engines off. I would guess that for high risk, power-hungry events like take-off & landing the jet would be the better engine. The turbo-prop would be used to extend range in flight. However, mass redistribution plus the extra mass & increased drag would have had a serious negative effect on the aircraft's combat performance.

Mustangs flew with pulsejets & ramjets

I noticed further down this page a photo of a P-61 Blackwidow using a ramjet, too. Looks oddly low, though, as if it's on an extendable pylon - or the landing gear on a '61 is a lot longer than I realised.

[RussC]

The prop's feathered, Kit, so it ain't shutter speed - the engines off. I would guess that for high risk, power-hungry events like take-off & landing the jet would be the better engine. The turbo-prop would be used to extend range in flight. However, mass redistribution plus the extra mass & increased drag would have had a serious negative effect on the aircraft's combat performance.

Mustangs flew with pulsejets & ramjets

I noticed further down this page a photo of a P-61 Blackwidow using a ramjet, too. Looks oddly low, though, as if it's on an extendable pylon - or the landing gear on a '61 is a lot longer than I realised.

 Its on a extending pylon, but what really caught my eye was the caption of it being an "airfoil ramjet" that's a mind blower. The ramjets of that era and right up to the 90's were all tube types, and were almost akin to combustion versions of musical instruments and useful in the lower atmosphere. The concept of an aerodynamic ramjet is one that has surfaced recently in the search for scramjet types to power aerospace (runway-to-orbit) planes. The big problem in designing jet and rocket engines for this is the varying conditions over the mission profile. A enclosed combustion chamber and nozzle that is optimized for one region of atmosphere or exosphere is less efficient outside of this region, both higher and lower. The one design that has been advanced is an aerodynamic nozzle, letting the air itself work as the nozzle or engine bell and thus have a full optimum range of combustion through the whole flight. And here we see possibly the idea being toyed with in the 40's !!!!

[MilitaryAircraft101]

IIRC Some early russian aircraft had mixed propulsuion...

[Logan Hartke]

Yes, that's what I meant, not turbojet, don't know where my head was.

The -123 DID fly in an all jet configuration. It had dual pods under the wings like a B-47, but I suspect not the same engines or it would have been faster than a Sabre!

Yes, I know, but my original quote was "turbojet, jet" instead of "turboprop, jet" which is what I meant.  I know it flew in all-jet, I was just being redundant initially.  Weaver was keen enough to notice it, thankfully.

Cheers,

Logan

[pyro-manic]

There must be some reason it never became common... experimentals are the only ones that come to my mind.

I would think it's mostly down to cost. More engines of different types which need more spares, trained crew, etc, as well as possibly different fuel types. Makes everything more complicated and expensive.

[Weaver]

It went through a brief phase of being done "on the drawing board" due to the horrific fuel consumption of early jet engines, which made the idea of a plane that could cruise efficently on it's piston engine but kick in the jet for combat/dash/takeoff seem attractive. As combat speed increased and jet enginesgot better, it began to look like a more and more dubious proposition though, particularly given the maintenance/logistic disadvantages.

Most of the successful combis seem to be "afterthoughts", i.e. jet booosters added to an aircraft that was strugging to maintain it's take off performance in the face of increased weight or hot'n'high conditions.

[Mossie]

Not a prop, but the Flapper ornithopter had mixed propulsion.  As the design weight increased, the designers realised they didn't have enough power to get it off the ground.  They said they were there purely to push air over the wings & didn't add to the thrust although their detractors accused them of 'cheating'.

[Caveman]

I cant seem to find a picture at the moment but im sure that the 262 was first flown with a piston engine in the nose, then a mixed set up before purely jets?

Or am i imagining?

[perttime]

I cant seem to find a picture at the moment but im sure that the 262 was first flown with a piston engine in the nose, then a mixed set up before purely jets?

Or am i imagining?

According to Wikipedia and vectorsite:

"The first test flights began on 18 April 1941, with the Me 262 V1 example, bearing its Stammkennzeichen radio code letters of PC+UA, but since its intended BMW 003 turbojets were not ready for fitting, a conventional Junkers Jumo 210 engine was mounted in the V1 prototype's nose, driving a propeller, to test the Me 262 V1 airframe. When the BMW 003 engines were finally installed, the Jumo was retained for safety, which proved wise as both 003s failed during the first flight and the pilot had to land using the nose-mounted engine alone."

There's a photo of the prop and jets Me 262 at:

http://www.meteorflight.com/A55D74/meteor.nsf/pages/jet_age-me262

[kitnut617]

"The first test flights began on 18 April 1941, with the Me 262 V1 example, bearing its Stammkennzeichen radio code letters of PC+UA, but since its intended BMW 003 turbojets were not ready for fitting, a conventional Junkers Jumo 210 engine was mounted in the V1 prototype's nose, driving a propeller, to test the Me 262 V1 airframe. When the BMW 003 engines were finally installed, the Jumo was retained for safety, which proved wise as both 003s failed during the first flight and the pilot had to land using the nose-mounted engine alone."

And here you can buy a model of it:

http://www.hpmhobbies.com/products/High-Planes-Messerschmitt-Me262V%252d1-Prototype-%28Kit-1%3A72%29.html

http://www.hpmhobbies.com/products/High-Planes-Messerschmitt-Me262V%252d2%7B47%7DV%252d3-Prototype-%28Kit-1%3A72%29.html

[jcf]

Yet another piccie of the XH-88H without the turbo-prop running! 

I have NEVER seen a pic with the prop rotating, either the engine didn't work or they were using STUPIDLY fast shutter speeds......

Evidently it was actually a propeller test vehicle, and was restricted from using the turbo-prop at high power settings and
low speeds because of insufficient rudder authority.

[PR19_Kit]

Yet another piccie of the XH-88H without the turbo-prop running! 

I have NEVER seen a pic with the prop rotating, either the engine didn't work or they were using STUPIDLY fast shutter speeds......

Evidently it was actually a propeller test vehicle, and was restricted from using the turbo-prop at high power settings and
low speeds because of insufficient rudder authority.

I've heard that before, but I've yet to see a photo showing the prop actually turning. Every one only shows it stopped and feathered.

I'm not suggesting that they never ran the engine, I've just not seen any evidence of it.