Could I steer this thread towards the same concept, only

in a

coaxial

helicopter? :)

My (shade tree mechanics degree) says two engines in a

coaxial

configuration could be interesting. :) If one engine

*could*

provide

enough power to maintain altitude, couldn't you toss the

need

for

autorotation? I'm ASSUMING the reliability of the rotary

built

for

proper aircraft use.

I know something along this line has been tried by the

Nolan

brothers

(two small two strokes)...I have a different twist in my

head.

I need

massive help!

Thanks guys
Phil

The problem with seperate engines on a coaxial helicopter is

that

the torque

differential would show up on the tail (rotor etc), and a

single

engine

failure
would spin you like a top.  A more direct coupling would be

in

order

for that application, and I do not know if you could sustain

on

half

power.  maybe crash more softly? Vance

If two engines drive the same input shaft to the transmission,

and are

coupled through a

mechanical diode, or sprag/overunning clutch, the loss of one

engine

will just reduce the power,

but not have an effect on the fuselage since the torque is being

counteracted by the two rotors

running in opposite directions.
One rotor inputs counter clockwise torque to the fuselage, and

the

other inputs clockwise torque,

thereby cancelling out the torque.
The same as a tandem rotor.
Here is a link to a page that gives some details on a good

coaxial.

Gyrodyne

Royce

Thanks for the Gyrodyne link Royce. I'd been reading through some

of

their files for about 9 months now.

The thinking behind this madness is to *attempt* to eliminate the

extra

linkage/hardware to the top rotor...KISS. This would toss

autorotation

out the window, but it does bring in the extra hardware to utilize

two

engines. Also, from what I've read, coaxial isn't as

"auto-rotation

friendly" as the standard one rotor/tail rotor set-up.

Take a McCulloch J2 gyro, toss powered coaxial rotors on it, and

that's

(mostly) what I'd be looking for. :)

??? Why would you want to eliminate the extra linkage to the top

rotor???

It is very true that "most Coaxials" are "drag queens", but they don't

have to

be.
Coaxial rotors autorotate just as well as a single rotor. Several

things that

you have do do somewhat differently on a coax than a single, but none

the less

they still work great. ask off list for details.
If you use a rotary engine to power the unit, one engine should be

just fine.

Royce

One turbo 13b with autorotation would be fine. That was my concern.

I'm guessing "off list" means via e-mail? :)

You got it.
Royce
royce@wayxcable.com

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