tdo
Heliman
Location: Germany
My Posts This: Topic Forum | Hey Peter,
1st of all, no, I havent't flown the UNI 2000 with 4 blades and glow.
Only two blades and 1600 mm rotordia.
Yes, you're right, the 10:1 ratio is stated for the 2 blade 1800 mm Rotordisc.
One reason might be, that the manual for the UNI 2000 was printed earlier than the 4 blade head was released 
Anyway, there are not too many choices left.
I assume that you're heading for an even bigger gear ratio than 10:1,
but that's not too easy to build.
I had to learn this when I modified the geardrive slightly on my UNI 2000 so that it fits the current engine a bit better than the original
gear combination which gave me 7,7:1.
Far too "long" for the O.S. 91 SX-HGL C-Spec.
So: how do you get "shorter" than 10:1?
Either getting smaller on the pinion, less then 22 teeth.
No smaller pinion available, as far as I know.
So get larger on the gearwheel.
10:1 uses 54 teeth.
Vario has some gearwheels which can be used instead of the Graupner parts, that's what I did, using a 52 t. wheel, which wasn't offered
from Graupner.
So Vario has one wheel with 55 t., using that one you'd reach exactly 10:1 (the original 22:54 combination gives you 9.81:1).
Not that much..
There's a wheel with 58 t from Vario, Prod. No. "44/45", using this you'd get 10,54:1.
Got to be a bit careful, since with different pinions and wheels, you get different distances between the axes of the engine and the gear drive.
Default is 38 mm, with the 58 t. wheel from Vario you'd get a distance of 40 mm.
Difficult to be done, you need to add 2 mm shims to the engine mount and modify the cooling housing to prevent the fan wheel from
scratching the housings wall 
Not sure, if the "SolidState" mechanic, when finally released,
gives you a different and more flexible choice of gear ratios,
we need to see what Graupner will release (and when!!!)
4 Servos: I tried it years ago, can be done, but the linkage of the
front nick servo is a bit nasty;
You have to bent a quite long connecting rod so that it can run aside from the cooling housing and then connect to the ball on the swashplate.
So it's not that exact, and quite weak.
Which helps in one perspective: You don't overload the servos
too much, since normally 4 servos are one too many, if not adjusted very carefully, the servos work against each other.
With one "weaker" link, that problem wouldn't be that big.
Finally, I've taken the 4th servo out again.
On the drawing I've seen from the SolidState mech., it looks like they
added some lever to connect a 4th Servo in a better way than it was possible so far.
Again, let's wait and see.
I plan to attend the Jet-Power Messe on Saturday; last year, the Graupner Product Manager for Helicopters, Wolfgang Simon, was there as well.
Perhaps I can fetch some informations on the SolidState 
We'll see.
Regards,
Thilo |
