Single Engined Twin Prop?

http://www.centennialofflight.gov/essay/Evolution_of_Technology/VSTOL_aircraft/Tech30G6.htm

Thats awesome! its so cool!! Its run by ONE turboshaft engine! Those wings are also the type I have in mind – low cord thick wings. My design also has a tilt in fact, but but a very small fixed tilt and does not aim to be a VTOL but a very conventional STOL. I think I’m going to get started with this new design, I’m just beginning to, well almost beginning to believe in a single engined twin prop.

http://www.centennialofflight.gov/essay/Evolution_of_Technology/VSTOL_aircraft/Tech30G6.htm

Excuse my ignorance here, but, what exactly would be the benefits of having 2 props on one engine ?

Contrarotative props can be useful to absorb the power of large engine (and negate the torque), but as for 2 separate props ?
You add complexity without eliminating the engine failure risk.

Hi Frank,

well, I am brainstorming some of my ideas. I am looking to design a single engined CAS platform that has great endurance and STOL capabilities. Now here are the possibilities:

1. Conventional single prop engine layout. with this pilot visibility is sacrificed and the nose cannot carry required sensors and other items like radar, IRST & nose mounted gun (well the last is possible of course, but can be a problem, particularly if you want a gun like that on an attack helo).

2. A twin engined plane with the twin props on the wings. This is an excellent design but twin engines means higher costs per plane, not suited for the swarm tactics I have in mind. Further, twin engines on the wings tend to make planes less agile and the required armoring for the plane’s vital areas has to be increased, given the greater area that would now need armoring. If WWII is anything to go by, its the single engines that really cut the cheese, so to speak. Further, in my plans, the larger single engine as opposed to the smaller twin engines would provide a commonality for other plane projects – with a larger single prop engine in production for the CAS aircraft, a complementary transport can be built with two of the CAS aircraft engines.

3. A design where th props are positioned in the rear – like many UAVs. This is the design that I have settled on for the past 3 years. This seems to get the best of both worlds – nose free for various items while single engined. However, because of the reduced wash over the wings, this increases the distance needed for take offs and landings as well as the minimum stall speeds and really low speed agility. These are all extremely vital for the CAS type I have in mind. I want my planes to have no need for airbases and be based along with my mobile armored divisions, as fully integrated units.

4. Of course one could just move to a turbofan engine, but I believe that a prop engine has its advantages over turbofans for the type of aircraft I’m designing; prop wash, efficiency, low speed flight and shorter take offs all favor props..

Quite a while back, I was involved in some contra-rotating propeller noise research.

Two candidates were chosen for flight measurements: the Fairey Gannet with its double Mamba engine configuration allowed pitch and RPM to be altered independently, and the Avro Shackleton (Mk2) which was contra-rotating props geared from a single RR Griffon engine (times four).

IIRC the Shackleton’s two props were equal and opposite RPM and pitch changed in combination. A horribly noisy set-up especially when the prop tips are a few inches from your ear when seated behind the pilot.

The advantage is that you recover the swirl from the front prop as extra thrust, but the efficiency gain from them is somewhat outweighed by the noise increase and extra weight/complexity.

Excuse my ignorance here, but, what exactly would be the benefits of having 2 props on one engine ?

Contrarotative props can be useful to absorb the power of large engine (and negate the torque), but as for 2 separate props ?
You add complexity without eliminating the engine failure risk.

thanks, 25deg south!!!

Salmson -Moineau S.M.1. – (here’s a dinged one) amongst many others.
Transverse rotary in fuselage ,driving 2 props by shafts and gears.

there has to be something more than the Wright flyer! 🙂

come on guys, rack your brains and the vast source of collective aviation knowlege, one last time.

Thats another find, but its sort of different from the way I’m looking at it.. the pretty much together..

Here are some pics:

http://scalemodel.net/pictures/WrightFlyer/WrightFlyer.jpg

http://www.flickr.com/photos/6element/26171339/in/set-40463/

Contra-prop Spitfire/Seafire?

hehehe, cheers mate!

Is there any such plane out there? I think such a plane is technically possible, although I may be wrong 😀 Such a plane could combine the advantages of a single engine with the advantages of a twin prop…

I am certain I can’t be the first person to think about it. 🙂

Duh! Wright Biplane?:D