Twin-Falcon or Twin-Viper

[Tophe]

Found that on the Net, from Canada, motherland of the F-16T (and dear JHM)...
I fear that's just 2 F-16 close together, without link, but what-if...? I like the asymmetry of such a twin, improving the view all around of the pilot in front... Maybe I will draw such a P-82.

[Tophe]

I will draw such a P-82.

here :

[elmayerle]

Mmm, a minor drawback to the configuration posted, the pilot appears to be in the plane of the aft prop, for some kinds of accidents, this is considered rather unsafe.

[Tophe]

Mmm, a minor drawback to the configuration posted, the pilot appears to be in the plane of the aft prop, for some kinds of accidents, this is considered rather unsafe.

^_^  I think the problem of such a model is not the pilot position, it is simply the ability to fly...  The probability of accident would be far above the one of a safe flight. Just imagine the take-off, on 4 main gears, unbalanced...
For the landing, there would be no problem, if I correct my drawing in a JHM-way (P-51T-2). This double would be a kind of Mistel. The goal of a mission would be to throw away the aft plane and the front plane would come back alone (and for that, a symmetrical tailplane does help, thus my correction). Yes, that would be wasting a precious engine and wing-frame, but that is the Mistel very principle, no ?
Well, Evan, just see it as a crazy imagination of a green young colleague coming out of engineering school. All the design bureau would laugh at him and the design would immediately be thrown away in the garbage can, without any building nor danger for test pilots. But the small plastic model secretly built at home could be kept, smiling, as a mistake.  No ?  

[elmayerle]

*chuckle* But it's in "pushing the design envelope" that new and useful concepts develop.  Not every one works, but they do keep the mind limber and open to new ideas.

[Tophe]

     

[Captain Canada]

Hey, those are F-18s, not 16s !



But who's counting, eh !

Neat idea, Tophe !

Crazy, but neat !

 

[John Howling Mouse]

Mmm, a minor drawback to the configuration posted, the pilot appears to be in the plane of the aft prop, for some kinds of accidents, this is considered rather unsafe.

I feel that way everytime I'm stuck on a BAe Jetstream: I always end up in the seat which is some 9 inches away from the wildly spinning prop's tip!

Don't think the 1/8" Lexan window would do much to protect me, eh?

Tophe, you are truly an "out-of-the-box" thinker.  P.S. That's English for "highly innovative"!

You keep those ideas coming!

 

[Tophe]

I feel that way everytime I'm stuck on a BAe Jetstream: I always end up in the seat which is some 9 inches away from the wildly spinning prop's tip! Don't think the 1/8" Lexan window would do much to protect me, eh?
Tophe, you are truly an "out-of-the-box" thinker.  P.S. That's English for "highly innovative"!

Thanks for your nice words, JHM, and thanks for answering my double tribute to your models (after the great F-16T of yours: TF-16 and P-51T-2... P-51T being the 'property' of dear TSR-Joe).

In the last dozens of years, I have never heard of a propeller running away from an engine, but this happened on one (or several) French flying boat of the 20s-30s for sure, I have read it in Le Fana de l'Aviation. One passenger had been killed but the fuselage was not completely destroyed and as the cockpit was not separated from the wings, the pilots succeeded in alighting on water in emergency. You see: propellers are very safe. If you are cut down in tiny pieces by one, the fellow passengers will survive anyway, probably.  

[Tophe]

Hey, those are F-18s, not 16s !

Oops, sorry Captain. I apologize...
And dear Alvis already built a Twin F-18...    

[elmayerle]

I feel that way everytime I'm stuck on a BAe Jetstream: I always end up in the seat which is some 9 inches away from the wildly spinning prop's tip! Don't think the 1/8" Lexan window would do much to protect me, eh?
Tophe, you are truly an "out-of-the-box" thinker.  P.S. That's English for "highly innovative"!

Thanks for your nice words, JHM, and thanks for answering my double tribute to your models (after the great F-16T of yours: TF-16 and P-51T-2... P-51T being the 'property' of dear TSR-Joe).

In the last dozens of years, I have never heard of a propeller running away from an engine, but this happened on one (or several) French flying boat of the 20s-30s for sure, I have read it in Le Fana de l'Aviation. One passenger had been killed but the fuselage was not completely destroyed and as the cockpit was not separated from the wings, the pilots succeeded in alighting on water in emergency. You see: propellers are very safe. If you are cut down in tiny pieces by one, the fellow passengers will survive anyway, probably.

Not just run-away props - belly landing with low-mounted enough engines can cause problems, too.

[Tophe]

Not just run-away props - belly landing with low-mounted enough engines can cause problems, too.

Question 1, dear engineer : is the ducted propeller inproving safety or efficiency, or both ? And why does this way has been almost cancelled everywhere now ?

Question 2 : I have read that in jet/fan engines, sometimes a compressor blade run away too, but as it is ducted, the only danger is fire, not hurting someone. Do you confirm ?

PS. Wanting to illustrate my question about ducted propellers, I have asked Google, and discovered this nice bird below, from http://www.329amphibian.com/static_model.htm .    Nice! Thanks!

[elmayerle]

Not just run-away props - belly landing with low-mounted enough engines can cause problems, too.

Question 1, dear engineer : is the ducted propeller inproving safety or efficiency, or both ? And why does this way has been almost cancelled everywhere now ?

Question 2 : I have read that in jet/fan engines, sometimes a compressor blade run away too, but as it is ducted, the only danger is fire, not hurting someone. Do you confirm ?

PS. Wanting to illustrate my question about ducted propellers, I have asked Google, and discovered this nice bird below, from http://www.329amphibian.com/static_model.htm .    Nice! Thanks!

Question 1:  It can, fi done right, improve both, but it generally adds a penalty in weight that's more than the benefits.  The closest you get these days is some of the very high by-pass ratio turbofans.

Question 2:  If it's just a blade that's shed, the engine is generally designed to contain it.  But if the problem is a rotor burst, you can't build a structure that will contain that much energy and there's an entire section of the civil Airworthiness Requirements, FAR's and JAR's both, on this subject requiring considerable analysis of an aircraft to show that it can survive an uncontained rotor burst.  These requirements are generally taken into considering in the initial layout and design of the aircraft.  As an example, the aft external fuel tank in the Lear 55ER was designed to be entirely outside the rotor burst zone in order to improve safety.

[Tophe]

Thanks for all these explanations that I have read nowhere! When you are retired, just write a book explaining aircraft design, I will order happily...