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HelicopterScale Model RC Helicopters › Problem with Vario G47/R22 Scale Rotor Head
JR Guy

Senior Heliman

Waikawa Beach New Zealand

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Hi Guys Im having a problem setting up my G47/R22 Scale rotor head.
I have all the phasing and swash plate set up correct I think, however in my pitch curve I have -3 bottom stick + 5 Mid stick however at top stick the pitch changes from +10 on one blade and +15 0n the other.
The diagramme from vario pic shows the mechanical phasing at 11 oclock on the swash with the blades running along the tail.
I cannot achieve that. My set up with the mechanical phasing on the swash at 11 oclock has the blades at 90 degrees to the body with the push rods in line with the mast.
With the swash dead level through its pitch travel and the push rods at the same length to the head why should there be such a difference in total pitch?
I have the push rods in line with the mast. Should the mechanical phasing be off set putting the push rods out of line?
your help is much appreciated.
Colin

JR Guy

01-14-2017 05:59 AM
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Phoenix NOTAR

Senior Heliman

State College, PA USA

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Colin,

I am assuming that you have Vario head #1005/49. There is no "phasing" needed to set up this head, so I am not sure where the 11:00 comment comes from. This set-up is quite different though, since the swash plate tilts left for nose down elevator, and dips to the rear for left roll.

I am thinking that your pitch differences issues will go away when the head is set up properly. Please let me know if your head IS set up in this manner, and you are still having the pitch issue.

I have set up these heads many times, and so I made this instructional write up:

I get this question a lot, since I fly a Vario R22 (electric) with the Vario V22 flybarless head.

I will try to make this as simple as explanation as I can, even though this head is quite different than most helis out there. I few points to remember; This rotor rotates COUNTER-clockwise on the R22, it has a 4 point 90 degree swash plate / servo connection, and most important... the rule that states that "the blade over the boom should not move with an elevator command” STILL applies!

This head is different than most because it has the link from the blade grip to the swash plate directly under the blade grip, rather than offset by 90 degrees (or less in a multi blade head). This means that the swash plate must move 90 degrees off from a typical 2 blade rotor head. For this application, the swash plate will tilt DOWN on the LEFT side for NOSE DOWN, and it will tilt DOWN at the FRONT for a RIGHT roll command. And just to add more confusion, the swash plate will RISE for LESS collective pitch, and LOWER for MORE collective pitch.

If the swash plate driver is installed in the normal way, with all links vertical and parallel with the main shaft, NO rotor head phasing is needed in the flybarless unit.

Since this is a 4 point 90 degree swash plate, the simplest thing to do is to revise which servo the FBL unit “thinks” is connected to which position on the swash plate. With a Heli Command / Bavarian Demon unit this will mean that the “head servo 1” will connect with the servo attached to the REAR swash plate ball, “Head servo 2” will connect with the servo attached to the FRONT swash plate ball, “Head servo 3” will connect with the servo attached to the RIGHT side swash plate ball, and of course “Head servo 4” will connect with the servo attached to the Left side swash plate ball.

The swash plate must lower for positive collective, so reverse the servo direction in the FBL unit until this is correct for all four servos. The FBL unit MUST be mounted in a “normal” way, and the FBL unit must be told the ACTUAL mounting orientation used. (In my installation, upright with the connectors at the rear).

Now, confirm that the swash plate will tilt down on the left side for a forward elevator (nose down) command, tilt down on the right side for an elevator up (nose up) command, and it will tilt down at the front for a right roll command, and up at the front for a left roll command. And confirm that the swash plate will RISE for LESS collective pitch, and LOWER for positive collective pitch.

If you tilt the nose of the heli down, the swash plate should respond by tilting down on the right side. And if you roll the heli to the right, the swash plate should respond by tilting back (down at the rear).

Now confirm that the blade over the tail boom does not change pitch with an elevator stick command.

If all this is OK, then you are good to fly.

I hope that this helps those people trying to set-up, or understand why this head operates the way it does.

Sandy

01-14-2017 01:54 PM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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Sandy is dead on correct and he knows this specific rotor head set up like the back of his hand.. I spent at least an hour on the phone with him when I set up my R22 a couple of years ago. But I threw him a big curve ball My set up was 3 servo 120, so he really had to earn his supper figuring out my set up... We walked through the set up and he was in fact correct. BTW, thank you again Sandy for all the help that you gave me.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

01-14-2017 03:58 PM
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JR Guy

Senior Heliman

Waikawa Beach New Zealand

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Hi Sandy Barry
The head is the same as yours and my set up is correct all my inputs match yours. When I went to the field to fly last week everything was good running on the ground. In the hover all ok however when I applied more pitch the head started to vibrate so I landed.
We checked the Bavarian Demon 3sx and could not find a problem.
So! when we checked the pitch setting that is when I found the problem.
Generally when bottom stick and mid stick match I only check what I have at top stick on one blade.
When going over all settings looking for the problem that is when I checked both blades at top stick, to my disbelief 5 degrees difference.
I have checked the blades for twist and nothing wrong there.
I will see if I can paste a video.
Cheers
Colin

JR Guy

01-14-2017 06:03 PM
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Phoenix NOTAR

Senior Heliman

State College, PA USA

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Hello Colin,

Good to know that the basic set up is OK.

A few images of the head from the swash plate up would be helpful.

Is there any chance on the of the mixing arms 703/41 is installed backwards?

The 3SX only knows to control the swash plate. If there is a difference in collective pitch blade grip to blade grip, it is most likely in the mechanical head set-up. Unless the swash plate is tilting during collective movement.

Sandy

01-14-2017 06:30 PM
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JR Guy

Senior Heliman

Waikawa Beach New Zealand

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All sorted what a mistake.
I had the bell crank on the head reversed on one side.
All good, thanks for your input guys.
Cheers
Colin

JR Guy

01-14-2017 08:04 PM
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Mojave

Elite Veteran

Palos Verdes, Ca. USA

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LOL, it's always the easy stuff that gets us Don't feel bad, we've all had that kind of day... Glad you got it sorted out.
Barry

All helis and planes have an expiration date stamped on them...you only find it after you crash!!

01-14-2017 10:24 PM
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