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HomeScaleAircraftHelicopterScale Model RC Helicopters › First Hover tests - 4 blade head - UPDATED
11-25-2006 03:11 AM  11 years agoPost 41
rcadd1ct

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Richardson, Texas

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I concur.

Seems like the gyro is not lined up correctly.

-RCA .......... Making Cuisinarts Fly!!!!!!!

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11-25-2006 03:24 AM  11 years agoPost 42
racer944

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Greely, Ontario - Canada

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Well I have double and triple checked operation but I could definitely be missing something. When I tilt the helicopter forward or backwards in the pitch axis, it would appear to me that the gyro compensates by tilting the swashplate in the opposite direction...

Here is a picture of the mechanics... They have been disassembled to repair boom strike damage so the main shaft and head are not installed. To help situate the picture, you can see the hole for the main shaft at the top center of the pic between the two CCPM servos... The GY401 is my tail gyro, the CSM 180 is the elevator gyro, and the mixer is wrapped in foam below the gyro plate.

I kind of hope you see something I missed...

Eric

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11-25-2006 03:47 AM  11 years agoPost 43
rcadd1ct

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Richardson, Texas

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Does the gyro need to be phased like the head?

-RCA .......... Making Cuisinarts Fly!!!!!!!

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11-25-2006 04:25 AM  11 years agoPost 44
racer944

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Greely, Ontario - Canada

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To the best of my knowledge, no since the gyro operates on relative movement of the heli and not movement of the head/swash... i.e. it senses and corrects a forward/backward motion regardless of what caused it.

Eric

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11-25-2006 07:11 AM  11 years agoPost 45
rcadd1ct

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Richardson, Texas

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When you tilt the heli forward do you get a pure reverse swash movement or does it tilt at the phased angle?

-RCA .......... Making Cuisinarts Fly!!!!!!!

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11-25-2006 05:37 PM  11 years agoPost 46
AirWolfRC

rrProfessor

42½ N, 83½ W

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Is your picture showing the 180 gyro right side up like what is used for rudder control ?

Any gyro for pitch (and roll) needs to be mounted on it's side.
Notice the mounting of the 240 gyros on my home page.
-------------------------------------------------------------
edit
I found the 180's instructions and it looks properly mounted.
http://www.rcmodels.org/csm/ICG180.pdf

Need to look elsewhere for the problem
-------------------------------------------------------------

Position a blade over the tail boom. With the elevator (pitch) gyro in circuit, tilt the heli fore and aft (no side-ways roll) and make sure the blade over the tail boom DOES NOT show any pitch change. Forget the swash plate movement since you have something other than 90º phasing going on there.

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11-25-2006 10:21 PM  11 years agoPost 47
racer944

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Greely, Ontario - Canada

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Ok, I will try the blade over the boom, its worth double checking...

I suspect that it will be OK though as the the swash will move in its phased manner as the gyro is simply applying a forward or back command to the swash just like a stick input would. This is also the reason why the gyro does not need to be phased, but the axis of the elevator gyro does need to be mounted at a right angles to the fore/aft pitch moment of the helicopter.

By the way for what its worth, the aileron gyro (not shown) was mounted the same side up, but rotated 90 degrees in relation to the pitch gyro in order for it to have the proper inputs for a left right heli movement.

Cheers;
Eric

P.S. This will likely be a good thread for someone going through this in the future!

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11-26-2006 12:59 AM  11 years agoPost 48
Crewdogg998

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Michigan

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Racer,
You are right, this is a good thread! In fact, at the risk of sounding like an idiot, why do you need gyros for pitch and roll axis? I'd really like to read a "how to" for multi blade heads...

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11-26-2006 02:18 AM  11 years agoPost 49
racer944

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Greely, Ontario - Canada

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Actually you don't need gyros on either of the axis, many fly without, but the helicopter can be a bit more difficult to handle and fly properly without them. Its your choice.

It takes more practice and a really good understanding of the differences of flybarless/multiblade head in order to fly them well and feel comfortable. A simplistic example would be that multiblade setups have a tendancy to exhibit pitch up and roll sideways tendancies in forward flight depending on the flight situation, the control inputs, and the wind speed. Flight characteristics in some ways are actually more true to a full size...

The gyros (particularily the elevator one) simply add a bit of stability to the system and make a mutliblade heli act much more similarily to a two blade flybar equipped helicopter.

Your choice, practice, learn, and adapt, or use technology to help you control the craft and keep it more stable and predictable with flight characteristics that you are more likely accustomed to.

In my case the choice was simple, I wanted all the help I could get, and wanted all the advantages to help me fly it safely and in a scale, fun manner... Helitronix mixer and gyros for me.

Cheers;
Eric

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11-26-2006 04:40 PM  11 years agoPost 50
AirWolfRC

rrProfessor

42½ N, 83½ W

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It appears I have not mentioned it on this thread but reading the "No Flybar" page on my home page would be helpful to some.

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11-27-2006 10:17 PM  11 years agoPost 51
Crewdogg998

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Michigan

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Airwolf, thank you for the excellent article. I appreciate the time it must have taken you to put it all down for others to read, Steve

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HomeScaleAircraftHelicopterScale Model RC Helicopters › First Hover tests - 4 blade head - UPDATED
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