Props and Power plants

Merry X-Mas everyone.

So I have some time to spend online for a bit, and wondered if anyone would be interested in descussions about engines and propeller combos?

What I am looking for mostly is ideas and links to aircraft designed/envisioned in the inter-war period, say 1919-1939.

Specifically:
1) Contra rotating propellers.
2) Pusher Propellers.
3) In fuselage engine configurations.

I am looking for discussions for single engined, twin engined, and 'multi-enginged' aircraft.

I'll post a few pics in a couple minutes...
 
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Interesting.

What would you think for fighters? Pusher props with or w/o contra rotating? What about mixed push and pull experimental jobs?
 

perfectgeneral

Donor
Monthly Donor
I did wonder if the long prop shafts Bell were using on the Bell P-39 Aircobra could allow a set up like the Dornier Arrow Do-335. It already has the requisite tricycle undercarriage. The kingcobra turbocharge air inlet behind the canopy will help keep two engines fed with air. An engine either end of the cockpit leaves very little room for fuel tanks in the fuselage. Wet wings are a must. Through the spinner cannons fore and aft? Another in each wing reduces the fuel capacity again, so maybe not. Two through the prop space cannons in the nose?
 
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I personally like the looks of the XP-55. Not sure why just do. If tge wings could be designed to be folding I wonder if itbcould become a carrier fighter.
 

NothingNow

Banned
Through the spinner cannons fore and aft? Another in each wing reduces the fuel capacity again, so maybe not. Two through the prop space cannons in the nose?

Mounting a motor-cannon and a pair of synchronized cannon is about the only option you'd have for an effective armament with a configuration like that.
 
Can propellers be mounted on rings rather than a shaft? What I am after here is can you have a heavy nose mounted armament, inside the diameter of the 'ring' to which the propellers are mounted.

My personal pet project would be to get a single seat fighter version of a twin {in fuselage} engined aircraft, with the contra-rotating propellers mounted on rings, and a heavy weapons load fixed in the nose. I would envision the two engines each independently turning both propellers, so that in the event of an engine faliure, the plane may still survive.
 

Delta Force

Banned
Can propellers be mounted on rings rather than a shaft? What I am after here is can you have a heavy nose mounted armament, inside the diameter of the 'ring' to which the propellers are mounted.

You mean a ducted fan? How is the pilot supposed to see if it is single engined? You would have to mount the propulsion assembly to a wide diameter fuselage, and the cockpit would have to be mounted above that. At that point, it's easier to just mount the armament in the wings or use a twin engine arrangement so you can mount all the armament in the nose.

My personal pet project would be to get a single seat fighter version of a twin {in fuselage} engined aircraft, with the contra-rotating propellers mounted on rings, and a heavy weapons load fixed in the nose. I would envision the two engines each independently turning both propellers, so that in the event of an engine faliure, the plane may still survive.
If you have two engines you don't need a ducted fan, you can just mount all the armament in the nose to begin win. Also, do you mean twin fuselage (as in the F-82 Twin Mustang), twin boom (as in the P-38 Lightning), or two podded engines (as in the de Havilland Mosquito)? Twin boom and podded engines are the best for having a centralized battery in the nose. If you go with twin boom you have the additional advantage of being able to store fuel in the booms.
 
Well heck!:(

I just got my scanner working, and now I have a security issue with image shack. Dang it.

any other free image uploading sites I can try?

DOH!!!

I have forgotten how to google, lol. here we go.

Ok, in the upper left we have my {crappy} rendering of the twin drive shafts, along with their rotations, and the forward propeller ring. The aft, contra rotating propeller ring in the dotted and larger one.

Below that is the idea attempting to show the pilot seated between, between/above the engines.

In the lower right, a very bad sketch of an overhead view, and in the top right, just a outline of how the drive shafts would work within the two ring system.

Any flames, thoughts, or gales of laughter are welcomed...:eek:
 
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Well, here's a couple US pusher-props: XP-54, 55, and 6.

As for a push-pull, the only fighter I know is the Do-335. It's a bit of an odd duck, but I think it's kind of nifty.

Nice! The XP 56 is a bit of a fatboy, and the XP 54 seems a bit skeletal, but the XP 55 looks good.


Also, do you mean twin fuselage (as in the F-82 Twin Mustang), twin boom (as in the P-38 Lightning), or two podded engines (as in the de Havilland Mosquito)? Twin boom and podded engines are the best for having a centralized battery in the nose. If you go with twin boom you have the additional advantage of being able to store fuel in the booms.

Single fuselage, but both engines side-by-side, behind the cockpit. Also, would it be best to accept a wide body from the nose back to aft of the engines? Or a pointier nose that thickens rapidly to maximum needed to house the engines, and then narrows rapidly to the tail. Myself, I would like to have the nose and tail as close to blunt as possible (without having to scarifice much speed) in odrer to give as much internal room as possible.

Also, could a partial 'blended wing and body' be a useful inclusion for extra fuel storage?
 

perfectgeneral

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Monthly Donor
495px-Bell_P-39K-L_internal.jpg

This cutaway of the P-39 Aircobra shows the through propeller hub cannon and Browning 0.3" MG in the nose (synchronised) and wings. The Kingcobra switched to 0.5" MGs. I'd look for 1x37mm (hub) and 2x20mm (nose) at least.

If you can imagine a second engine behind the first (keep that frontal area low) and a prop shaft going back to a pusher prop behind the tail...
The wing would probably have to move back between the two engines to balance CoG and centre of lift. Great for visability.

Since the engines are back to back, the air scoop behind the canopy could fed both turbo-superchargers or one big shared one (trickier).

A rough cut and paste of the idea:

http://i9.photobucket.com/albums/a75/perfectgeneral/AltCobra-1.png

40490d31-ed9a-46a2-9941-cfc514905915.jpg
 
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Some alternate configurations for the Do-335 that don't require some compromise for propellors at both ends.

The aforementioned Fairey P-24 engine was, sadly, a road not taken due to politics.

Mounting V-12 engines side by side reminds me of changing sparkplugs on a V6 Chrysler mini-van. Four are easy, one is tricky, and one requires major surgery.

It's kind of hard to imagine wizard propellor drive technology pre-1939 when variable pitch hadn't been around all that long, and British fighters didn't get them until 1940. I had just looked up an Aviatik twin-engine bomber from 1916, yesterday, which had two engines in the fuselage driving both pusher and tractor props between the wings through drive-shafts. Big failure.

DornierDo336sm.png
 
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