Turboprop Position

[Librarian]

Whilst enjoying Chris' build of the Me509 I was wondering if the piston engine could be replaced by a turboprop engine...radiator as airscoop and an exhaust at the rear. Could this still be possible with the prop shaft being a long one?

[wuzak]

Whilst enjoying Chris' build of the Me509 I was wondering if the piston engine could be replaced by a turboprop engine...radiator as airscoop and an exhaust at the rear. Could this still be possible with the prop shaft being a long one?

Yes, but I think you would want the turboprop near the CoG.

You could have a long exhaust pipe, or a side exhaust or a bifurcated pipe, like the Hawker Sea Hawk.

[Dizzyfugu]

The selling point of a turboprop engine is (also) its relatively small size and low weight. Early German turboprop engines were rather bulky things, though - in this case a mid-fuselage placement with an extension shaft for the propeller like the 509 arrangement would make sense. Air intakes could be added as "ears" to the fuselage flanks, maybe above the wing roots, and an tailpipe could either be extended to the fin, or use a side exhaust - either bifurcated, or just on one side, to counter propeller torque. The 509 has a suitable size for such an engine.

As a side note, there was a real world plan to convert the light Focke Wulf Flitzer jet fighter to a turboprop attack aircraft, just with a single tail boom and a propeller in the nose.

[kitnut617]

As a side note, there was a real world plan to convert the light Focke Wulf Flitzer jet fighter to a turboprop attack aircraft, just with a single tail boom and a propeller in the nose.

Well considering the 'Flitzer' was a paper project itself, just how RW was it ?

[Librarian]

It's quite a fun idea all in all. Thanks all for the info.

Just out of interest, if three 509s (for eg) were built, one piston, one turbo prop and one jet, which would be the better option for a balance of  speed and range. My money would be on a turboprop but I'm lousy at gambling

[jcf]

It's quite a fun idea all in all. Thanks all for the info.

Just out of interest, if three 509s (for eg) were built, one piston, one turbo prop and one jet, which would be the better option for a balance of  speed and range. My money would be on a turboprop but I'm lousy at gambling

In period, not likely to have range improvement, as those early turbo-props designs
were basically the then current turbo-jet designs driving a prop. Fuel consumption
was poor.
The majority of engines designed as turbo-props from the start came a bit later.

[JayBee]

This is a rather nice idea but one point that must be considered is the simple fact that turbo-props are so much lighter than their combustion engine equivalents.
So the positioning of the engines has to be carefully balanced. Consider the various turbo conversions of the C-47, the engines had to be placed well forward.

[Librarian]

Very interesting subject, aero-engines. Didn't know a lot and spent some time yesterday reading about them. I found the big airliner turbofans fascinating...taking the turboprop to the next evolutionary scale. I had no idea that the engine core produced so little thrust with the vast majority coming from the fans. Its no wonder fuel economy is so good and the noise levels have reduced so dramatically.

I do miss the crackle of Tridents coming over the house though, and that wonderful whine of the early 747 engines

[zenrat]

Very interesting subject, aero-engines. Didn't know a lot and spent some time yesterday reading about them. I found the big airliner turbofans fascinating...taking the turboprop to the next evolutionary scale. I had no idea that the engine core produced so little thrust with the vast majority coming from the fans. Its no wonder fuel economy is so good and the noise levels have reduced so dramatically...

That's why big airliners pick up and throw taxis (see Mythbusters) - because they are moving so much air.

So why not wing mounted turbofans?  Something like a Hercules with the turboprops replaced by them?
Or a B-36 with the fans at the back.
Wouldn't all that air moving over the adjacent wing section generate lift meaning a shorter take off run?

[NARSES2]

This is a rather nice idea but one point that must be considered is the simple fact that turbo-props are so much lighter than their combustion engine equivalents.
So the positioning of the engines has to be carefully balanced. Consider the various turbo conversions of the C-47, the engines had to be placed well forward.

Perhaps with a turbo-prop 509 you could have a large cannon mounted in front of the engine and firing through the prop shaft as a counter balance ?.

[PR19_Kit]

So why not wing mounted turbofans?  Something like a Hercules with the turboprops replaced by them?
Or a B-36 with the fans at the back.
Wouldn't all that air moving over the adjacent wing section generate lift meaning a shorter take off run?

Isn't it because with the wing in the way the engine wouldn't produce as much thrust to shove the whole assemblage forward?

But to an extent aircraft like the A-400M Atlas are like that, with that vast number and area of prop blades.

[dogsbody]

What about a refined Jendrassik Cs-1?

https://en.wikipedia.org/wiki/Jendrassik_Cs-1


Chris

[wuzak]

What about a refined Jendrassik Cs-1?

https://en.wikipedia.org/wiki/Jendrassik_Cs-1


Chris

Probably would need a couple. Like a Double Mamba.

[zenrat]

What great looking nacelles - like science fiction engines - all those lovely lumps set off with space props on the front.

[PR19_Kit]

Great looking? 

I think they're the ugliest turboprop nacelles ever, but we're all different, thank goodness.