F1992

My Feedback: (4)

1. Thanks to all who gave me recommends about "prop w/symmetrical profile" (06/07?04).
Specila thanks Spaceclam, Tall Paul B. Lanterman... You forse to work my brain.

2. I (dilettante) ordered half set blades from "Draganflyer-4" for my Fly Platform, but Spaceclam "open me eyes" (Russian expression) on problem.
It is tru that this rotor blades don`t fit for my FP (GW~ 2lb, OS.40) ...

Therefore if half set blades (right and left rotation) need I am ready to sell it, of course more cheaper. I even unpacking parsel.

3. For increase of thrust of RC VTOL useful to use duct tubes. It increases thrus 40-48%!!!. It tested on realy military helicopter.
Right now design of duct tube (that manufactoring) is "parody" on it and only.
At least i long tme "dug' infop but all is invain..
Inside shape of duct tube have to be done w/special profile and after prop duct have to have conuc.
May be anybody know about correct design of ducted tube for RC models?
And else, for RC VTOL probably to used motor (Japan) w/reductor from Soarstar (it is cheapper)[8D].
Thanks
<[email protected]>

scubyfan

Including a "lip" on the duct tube supposedly helps thrust by 30%, though I cannot verify that. Also, if you have a conical thing below the engine, that will help prevent "suck" forces from injuring lift, and have added 10% ish.

Good luck!

F1992

My Feedback: (4)

Sir,
For information only.
1. That thrust increase... it was checked on military Hely (1991). It is fact. By the way only today I meet w/person who calculated this thrust. He confirmed that thrust and according to calculation and according to banch test gave ~45-48% plus.

2. Engine disposes out of duct (tube), see for axample design of HOVTOL, US Patent 5,890,441 (4/99)
3. I understand that on rc model very difficult to get result ~45%, but result will be very positive any way.
4. One more: PROFILE of duct (tubing), which we see everywhere on rc models is "parody" on correct design.
5. I am beginner in field of RC model, but I have bigger experience as aviation engineer.
I don`t wishe to argue...because I say ONLY, that there are big reserve of improvement of technical parameters.
Thanks.

Spaceclam

If you have acces to a foam cutting unit or can cut it precicely yourself, you can cut out a little unit that goes around the edges of the model (mounted on the booms) and cut holes for the props. styrofoam (sp?) weighs very little and can be harnassed very easily. see, when a blade spins like that it wastes a lot of air coming off the tips. you want to be able to turn that into downward thrust without negating all you have gained with the added weight of the ducts themselves. Oh by the way, you may want to order one of those zinger pusher props because the way the blade is curved it may have been intended as a reverse rotation puller prop. give it a shot, they are only $4.

scubyfan

What an *******. I was trying to be helpful.

F1992

My Feedback: (4)

Sir,
I thinking to make it, but after of tested of My Flay Platform.
In my project (FP) I using timing belt, as transmission device. After test of FP i will start this project. But I thinking that surfice won`t enough "clean" as mashinned surfice of aluminum... plus I don`t have of experience of work w/foam.
Else shape of intake tube (duct) have to done to according of special curve or at least like Radius..
may be balsa can be better...
Any way i have Co., where I am able to do it.
Thanks

F1992

My Feedback: (4)

Sir,
I understamnd it exactly.

Ideas are many but life is short.

Thanks