Mid fuselage propellors

[Caveman]

A topic to discuss and reveal aircraft, designs and their uses, which have their propellors (not engines) located mid fuselage. Or which aircraft would look good (cause thats basically the most important thing...) with mid fuselage props?

I know of a couple of examples to illustrate...

Daimler Benz Jager

I think for the purpose of better visibility... though looking at that loooooong nose im not too sure anymore...

and of course the triebflugel


there is also the SPAD A2

Before interrupter gears there was this...

also, more modern is the Hummingbird aerobatic aircraft concept (which has flown as a scale model)

very similar in configuration to the heinkel wespe and lerche

any more for anymore?

what are the benefits of a mid propellor aircraft and would they outweigh the structural penalties and the power train complication/losses?

[PR19_Kit]

There's the Fantrainer and the Optica, both of which have ducted fans behind the cockpit area, and are similar in concept to Hummingbird.





As for the structural and visibility issues, I'm not sure I care too much, they all look ultra-cool! 

[jcf]

The Gallaudet company in the US had several WWI era designs that featured an amidships propeller.
The most famous were the single D-1 (two Duesenberg engines) and and two D-4 (single Liberty) floatplanes
built between 1916 and 1920:


The unbuilt Gallaudet amidships-propeller, front-engined monoplane designs included both two-seat military and single-seat
mailplane types. I'll dig out and scan some drawings later.

[GTX]

One I did a while back:



Regards,

Greg

[PR19_Kit]

Is that Zero-based Greg?

[raafif]

if 1 is first & 2 is second, I score GTX's drawing a Zer0 


One of us Whiffers posted his Macchi C-213 on his own site -- unfortunately, both guy & his site have disappeared.

[Pablo1965]

Very interesting and suggestive. 

[Weaver]

With a traditional small-diameter propellor shaft, I suspect any advantages are strongly outweighed by the structural problems, which is why there've been relatively few such designs proposed and even fewer produced. The ducted fan is one solution to this, since it's approaching the structural condition of a single-engined jet plane with a very wide engine.

Another approach might be to have many blades on a wide-diameter ring which runs around the outside of a stationary, and stucturally sound, tubular fuselage. The ring could have internal gear teeth driven by a gear attached to a piston engine in the fuselage, or for a moden one it could perhaps be gas driven by exhaust from a turbine (making it, in effect, an unducted turbofan/propfan). The ring and it's associated bearing surfaces would be awfully heavy though, and again, it's hard to see what the advantage would be. No reason not to do it "just 'cos it looks cool" though....

[rickshaw]

Didn't several Luft'46 designs feature a front fuselage supported by canards which were in turn connected back to the main wing so getting around the structure problems of using a thin drive shaft?

[Weaver]

They did indeed.

The problem with all these things is not so much how to do it as what's the point? There don't seem to be an compelling advantages of the layout that couldn't be acheived just as well by say, a J-21-style pusher-engined twin-boom design that has far fewer structural challenges.

[PR19_Kit]

With the Treibflugel there's an obvious reason why the wing/prop is in the middle, and that's because it IS a wing/prop. The lift generating part of its function would have been best exerted in the centre of the airframe. Which reminds me that I have one in The Loft somewhere, I must get it out and think what to do with it........

It's darn difficult seeing why the DB thingie should want the props in the middle though, even though it looks outstanding! 

[albeback]

With the Treibflugel there's an obvious reason why the wing/prop is in the middle, and that's because it IS a wing/prop. The lift generating part of its function would have been best exerted in the centre of the airframe. Which reminds me that I have one in The Loft somewhere, I must get it out and think what to do with it........

It's darn difficult seeing why the DB thingie should want the props in the middle though, even though it looks outstanding! 

Agreed, they DO look good - especially the D B Jager! Just one small problem springs to mind!! How is the pilot supposed to abandon his aircraft in an emergency without being sliced & diced? one assumes some type of ejection seat or, detachable nose section?

[RussC]

With the Treibflugel there's an obvious reason why the wing/prop is in the middle, and that's because it IS a wing/prop. The lift generating part of its function would have been best exerted in the centre of the airframe. Which reminds me that I have one in The Loft somewhere, I must get it out and think what to do with it........

It's darn difficult seeing why the DB thingie should want the props in the middle though, even though it looks outstanding! 

Agreed, they DO look good - especially the D B Jager! Just one small problem springs to mind!! How is the pilot supposed to abandon his aircraft in an emergency without being sliced & diced? one assumes some type of ejection seat or, detachable nose section?

Same problem with the Triebfluegel and with combat helicopters using ejectors...answer, destructing prop or rotor hubs. Also dangerous are the rear pusher podded types like the Tachikawa Ki-94 or jets like the Gotha P-60A, the VolksJaeger and the F-107.

[PR19_Kit]

Same problem with the Triebfluegel and with combat helicopters using ejectors...answer, destructing prop or rotor hubs. Also dangerous are the rear pusher podded types like the Tachikawa Ki-94 or jets like the Gotha P-60A, the VolksJaeger and the F-107.

Yes, that's the answer. Blow the blades off as the first stage of the ejection sequence. I think one of the Russian combat choppers was the first to do that in the RW, the Mil 28 perhaps?

[Weaver]

It's the Ka-50 Hokum that has the ejector seat Kit. Not so much a seat as a "pack" actually: when you pull the lever, the rotor blades jettison on explosive bolts, the seat tilts forwards and a rocket that's not attached to the seat fires, dragging you out on a lanyard attached to your parachute harness (striking a Rocket Man pose is optional).....in theory. Of course, if the damage that's forcing you to eject has cut the wires to the explosive rotor bolts.....