Spitfire engine test bed - DONE!

[The Rat]

...indeed may NEVER have done it,

Well, the jerrys did, but polite people don't speak of such things, 

A turboprop Spitfire? How about a Python then? 

Going from about 1,500hp to around 3,500hp might require it being exclusively tested over the ocean, so that when the wings peel off there's less chance of them slicing up pedestrians when they land.    And the Python weighed in at 3,450lbs, the Merlin was less than half that.

Armstrong Siddeley Mamba? Positives: It would have about the same power as a Merlin, 1,500hp, and half the weight. Negatives: C of G changes would require major front-end modifications. You could stuff a lot more fuel in an extended nose to compensate, but when the fuel gets low the C of G would slide back. And I'm not 'mathy' enough to figure out how much nose extension would be required to compensate without ballast. I'll leave that up to more qualified engineering types, like, maybe, 'Mr. Tilt'? 

[PR19_Kit]

A Python??  I thought they were pretty huge (at least they look it on Wyverns).

Yeah, they are, that's JUST why I suggested it. 

It'd make the Speagle look as it had a lawnmower engine.   

In actuality I doubt I could make it fit at all.

[zenrat]

And I think I'm on a roll for re-engining Spitfires Dave, they hardly did it in the RW, indeed may NEVER have done it, so it's ripe for people like us.

A turboprop Spitfire? How about a Python then? 

A Python??  I thought they were pretty huge (at least they look it on Wyverns).  Tbh I was thinking more RR Dart or a Mamba.  A Trent I think would rather broad in the beam and difficult to blend into a Spitfire.

IRL a Dart was fitted to a Mustang.  So one should fit a Spit.

[Old Wombat]

I wonder how the torque of those big turbo-props would effect the handling during take-off & landing with those dainty, narrow-tracked legs? It was, from all reports, bad enough with the Merlin & Griffon. 

[chrisonord]

Very nice Kit 
A turboprop, is a must, and being whiff world, you can design and build your own to fit the aircraft. Contra prop, small intake underneath the original nose and a couple of exhausts dangling out from the underside. I have done such several times.

[PR19_Kit]

I wonder how the torque of those big turbo-props would effect the handling during take-off & landing with those dainty, narrow-tracked legs? It was, from all
reports, bad enough with the Merlin & Griffon. 

That's a good point, do turboprops have lots of torque like big piston engines?

Part of me says because they have a large number of small diameter bits all whizzing round at horrendous speeds that they won't major on torque, but then another part says that they've moving round pretty large props and that must require bags of torque.

[Wardukw]

I wonder how the torque of those big turbo-props would effect the handling during take-off & landing with those dainty, narrow-tracked legs? It was, from all
reports, bad enough with the Merlin & Griffon. 

That's a good point, do turboprops have lots of torque like big piston engines?

Part of me says because they have a large number of small diameter bits all whizzing round at horrendous speeds that they won't major on torque, but then another part says that they've moving round pretty large props and that must require bags of torque.

From what i remember Kit ,,it's the propellors which are the problem with the torque problems,,just like a chopper ..if it looses its tail rotor the fuselage will spin under the main rotor dew to the spinning of the main rotor .when flying a helicopter its very normal to have more pressure on the right foot peddle to counter the torque of the main rotor ...it's like taking a bicycle wheel and spinning it while holding it ,,when you try to take it from the vertical to the horizontal you can feel the torque in the wheel .
The Beaufighter didn't have one left/one right spinning engines and it was something new pilots had a problem with ,,quite afew accidents happened taking off because of that ,,unlike the P-38 Lighting with had   that and taking off was much easier .
The simple fact is the bigger the prop and the fast it turns ,,the more torque your going to get no matter if its a piston engine or a gas turbine .

[The Rat]

The simple fact is the bigger the prop and the fast it turns ,,the more torque your going to get no matter if its a piston engine or a gas turbine .

MASS + VELOCITY = HOLY CRAP!

[buzzbomb]

Been a great ride on this one. Thanks, fine work and great info on the way.

[Wardukw]

The simple fact is the bigger the prop and the fast it turns ,,the more torque your going to get no matter if its a piston engine or a gas turbine .

MASS + VELOCITY = HOLY CRAP!

EXACTLY !!  

[Old Wombat]

Most early jet engines had all the blades rotating in the same direction*, which did induce noticeable torque, but not as much as later piston engines turning big props, & most early jet aircraft were twin-engined, which reduced the torque effect.

However, add the effect of a prop to the turbines & you have even more torque ... Unless the prop turns in the opposite direction to the turbines, when they cancel out somewhat.




[*: Later jet engines were developed with alternate sets of blades rotating in opposite directions, this not only pretty-much eliminated any torque effects, it also improved engine efficiency.]

[PR19_Kit]

[*: Later jet engines were developed with alternate sets of blades rotating in opposite directions, this not only pretty-much eliminated any torque effects, it also improved engine efficiency.]

Ah, but if you had a two spool, opposite rotating turbine driving a single rotation prop, the most likely config in 2025, would there be a large torque effect, and which direction would it go?

Of course a contra-prop on such an engine would cancel out ALL torque effects, but that's far too simple for this Forum!

[Old Wombat]

[*: Later jet engines were developed with alternate sets of blades rotating in opposite directions, this not only pretty-much eliminated any torque effects, it also improved engine efficiency.]

Ah, but if you had a two spool, opposite rotating turbine driving a single rotation prop, the most likely config in 2025, would there be a large torque effect, and which direction would it go?

Of course a contra-prop on such an engine would cancel out ALL torque effects, but that's far too simple for this Forum!

Turbines would cancel themselves out, the blade would be your source of torque, inducing a roll opposite to its direction of rotation (Newton strikes again!).

Force would depend on the length & mass of the blades.

[Wardukw]

[*: Later jet engines were developed with alternate sets of blades rotating in opposite directions, this not only pretty-much eliminated any torque effects, it also improved engine efficiency.]

Ah, but if you had a two spool, opposite rotating turbine driving a single rotation prop, the most likely config in 2025, would there be a large torque effect, and which direction would it go?

Of course a contra-prop on such an engine would cancel out ALL torque effects, but that's far too simple for this Forum!

Yep what Guy said 
The contra props are the perfect way to eliminate torque..exactly why helicopters with contra rotating rotors don't need a tail rotor 

[Spino]

[*: Later jet engines were developed with alternate sets of blades rotating in opposite directions, this not only pretty-much eliminated any torque effects, it also improved engine efficiency.]

Ah, but if you had a two spool, opposite rotating turbine driving a single rotation prop, the most likely config in 2025, would there be a large torque effect, and which direction would it go?

Of course a contra-prop on such an engine would cancel out ALL torque effects, but that's far too simple for this Forum!

It should make the aircraft want to rotate in the opposite direction of the prop rotation I believe.