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Home✈️Aircraft🚁HelicopterFuel-Helicopters New or Limited ActivityGraupner › Graupner UNI 2000 + 4 blade setup
09-17-2009 12:33 PM  11 years ago
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Bang68

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Denmark

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Graupner UNI 2000 + 4 blade setup
Hello !

I am not quite sure if the Graupner 4 blade 1800 mm setup will go with the glo UNI 2000 mechanic or if was only intended for the turbine versions.

If so what sort of gear ratio ect.

Any info preciated !

Regards

Peter B
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09-17-2009 02:18 PM  11 years ago
tdo

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Germany

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Graupner lists the 4 blade head (No. 4448.400) for the UNI 2000 and for the Turbine mechanic.
Blades are two sets of No. 1272, 885 mm long.
So these should give you about 1820 mm Rotor Dia.

The head isn't really a bargain at 766,50 € though
Plus two blades sets, 114,00 € each, we're talking almost 1k €.
Plus the 4 blade tail rotor (No. 4448.450) ?
But: A nice scale setup, indeed.

For the gear ratio: Graupner recommends a 10:1 ratio when running
1800 mm dia., which can be built using the Clutch Bell 4448.122 (22 teeth) and the Ring gear 4448.107A (54 teeth).

Infos:
UNI 2000: http://www.graupner.de/fileadmin/do...gen/4448.LN.pdf

4 blade head: http://www.graupner.de/fileadmin/do...en/4448.400.pdf

4 blade tail: http://www.graupner.de/fileadmin/do...en/4448.450.pdf

Cheers!
Thilo
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09-17-2009 08:27 PM  11 years ago
Bang68

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Denmark

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Thilo !

Thanks for your efford !

The 10:1 ratio states as you say for 1800 mm rotordisc, but I believe it is based from a 2 blade head and not a 4 blade

Is is for a Koala so I will only need a 2 blade on the tail.

I have decided to use 4 servos for cyclic on the Uni 2000 but maybe the current Uni 2000 is not really up for that and hopefully the new stronger revised mechanic will soon be released

Have you flown with the Graupner 4 blade with glo ?

regards

Peter
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09-18-2009 06:52 AM  11 years ago
tdo

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Germany

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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
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09-20-2009 08:11 PM  11 years ago
DWyn

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FAREHAM, Hants - UK

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Hi I am running the robbe 4 bladed head (need to drill mainshaft to fit) with the 2000 mechanics running an OS 61. Have tested it in pod and boom and now in Agusta 109 with a V Bar.
Have run SAB 660's and NHP 660's am looking for semi sym 680's to try now.
Trex 250, 450, 600E&N MSH Protos and Blitz Avro
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