schluter expert rotor head !!

[andre94120]

Hello
Excuse me , I don't speak German
I don't understand how Schuter Expert rotor head works !
As pitch is changed from low or high to "MID TRAVEL" , flybar in center of the hole of rotor head plates ,it results in a 3 or 4 mm play in flybar : balls not conected anymore to the blade holder arm because to let the flybar go high or low , the balls are fixed to flybar while the flybar is up or low
I hope you understand
Thanks for help
Here the photo of the head :

http://vrhc.co.uk/RC%20Helicopters/Germany/Schluter/Control%20Systems/1974-09%20-%20New%20Schluter%20head%2001.jpg

Andre French oldies addict

[Jan74]

AW: schluter expert rotor head !!

Hello Andre,

I never flew this Rotorhead, but I have a little bit expierence on the Schlüter Fixed pitch version and collective version for the system 80. The rotor head in your discussion is from 1973, the very first collective head from Schlüter. It was a simple construction without any mixing device, this was the reason, the flybar had to move up or down to increase and decrease the blade angles. So, on your picture, the links W1 and W2 have to push the flybar to increase the blade angles simultanously (collective). The blade arms are connected to the flybar by a spherical bearing and they are following each change of the flybar, either for cyclic or collective inputs.

The Problem with this head is a limited travel for cyclic in extreme positions (up or down).

It was then 1975, Schlüter introduced a new Head with separated Collective/Cyclic control for the Helibaby.

Perhaps this information helped you a little bit, my english isn't perfect, sorry.

best regards

Jan

[andre94120]

AW: schluter expert rotor head !!

Hi Jan
Your English is perfect
In Fact I understand how it works , but my problem is :
To allow flybar moving up and down , balls are fixed to the flybar at a certain distance , but in the middle of travel of the flybar , let' say , centered in the plate holes , you get 3 or 4 mm play because the balls don't touch anymore the arms of blade holders : this is because the arms are more distant each other than up or down
I hope you understand !
Regards
Andre

[Jan74]

AW: schluter expert rotor head !!

Hi Andre,

Oh, yes, of course, now I understand!! The only possible way to not have a blocking or extreme play, would be sliding balls on the flybar. Let's see, if any other can explain us the solution.
Comme une rotule glissante monté sûr l'arbre, si tu parle français! Je crois, c'est mieux pour les autres de continuer en anglais.

Regards

Jan

[WGS]

AW: schluter expert rotor head !!

Hi Andre

To allow flybar moving up and down , balls are fixed to the flybar at a certain distance , but in the middle of travel of the flybar , let' say , centered in the plate holes , you get 3 or 4 mm play because the balls don't touch anymore the arms of blade holders : this is because the arms are more distant each other than up or down

you are right, there is some axial play in the stabilizer bar, but that simply doesn't matter. The stabilizer bar got out of the center when the rotor was in rotation, but you had to live with that "misbalance": In fact it worked nevertheless.

[andre94120]

AW: schluter expert rotor head !!

Hi Wolfgang
I am surprised by the answer ! I trust you but it seemed to me It would not work .
I was looking for a mecanical solution to push the ballsn out with springs fitted on the flybar , living the balls free , sliding on the flybar : what do you think ?
I am restoring a Gazelle and will let you know how it works
Thanks
André

[WGS]

AW: schluter expert rotor head !!

Hello Andrè,

believe me, it works. I have some of these "Expert" rotor heads.

What is the sense of restoring an oldfashioned model and change its original design at the same time?
Of course these models were far from being perfect, but they worked, and the reason why we restore them is in most cases to get a feeling for how they worked and to fly them within the limits of their design.

By the way: You cannot compare the collective pitch range of the "Expert" rotor with that of today's models, it was very small (same is with the Graupner Bell 212 and the Kavan JetRanger). Models of the early 70s with collective pitch are not meant to fly with a constant rpm and thrust control by the collective. They were still rpm-controlled modells with a slight amount of collective pitch to increase the responses to the lift control in hovering.
With this small up/down movement of the stabilizer bar for collective pitch it's axial play can be neglected.

[andre94120]

AW: schluter expert rotor head !!

Hi Wolfgang
I agree with you : flying these models like in those days
I am an oldies addict , just look here : all are in flying condition :
andre's gallery
here the videos
andre94120 - YouTube
I know what is to fly a Bell 212 , a Kavan , .....
I will leave like original like my other helis
My question was : will it shake ? you answered NO . Once again I believe you
I learned so much from this forum despite I don't speak German
THANKS again
Andre

[WGS]

AW: schluter expert rotor head !!

Hi Andrè,

My question was : will it shake ? you answered NO .

I didn't say, that it does not shake at all, but there are so many possible reasons for shaking or vibrations in the design of these models,
that the little axial play in the stabilizer bar can be neglected.
Remember that people in those days flew these models with a lot more (vibration-) sensitive r/c equipment without problems.

[andre94120]

AW: schluter expert rotor head !!

Hi
Here is a video of first flight : very surprising how well it behaves "without vibrations" !!
Best regards
Andre
Schluter Gazelle 1973 - YouTube

[UliF]

AW: schluter expert rotor head !!

Bonjour André,
Sympa!
J'ai admiré certains de vos très beaux modèles-oldie sur "youtube" et "runryder".
Que diriez-vous d'une visite à la rencontre d'amoureux de vieux helicoptères de cette année à Kitzingen sur 5/6 Juillet 2014?
Il serait agréable d'accueillir un ami des anciens modèles-hélicoptères de l'autre côté du Rhin sur le meeting.
amicalement, Uli

[andre94120]

AW: schluter expert rotor head !!

Bonjour
Très touché par l'invitation , MERCI !
Je vais y penser , pourquoi pas ....!
A bientôt
André