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09-02-2003 01:47 PM  14 years agoPost 1
Rawlie

rrApprentice

JHB

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Hi

I'm running a Century Hawk with a MDS 38, GV-1 governor and a CSM200/9253 combo on the tail.

My GV-1 is set to 2 headspeeds: 1550 or 1750 rpm.

When I do a full power climb out at 1550 rpm the tail tends to swing anti clockwise, sometimes up to 90 degrees. When I repeat this climb out at 1750 rpm the tail stays virtually dead straight.

My suspicion is that at 1550 rpm the tail rotor cannot generate enough sideways thrust to combat the torque, but at 1750 rpm its spinning faster and is thus more efficient.

The gyro gain cannot be turned up higher otherwise the tail wags.

I've got a torque tube in the tail so there isn't any "wind up".

Do I need bigger tail rotor blades? Its not a big problem as I'm starting to fly around with 1750 rpm more and more, but I was just wandering if this is common ... ?

Thanks
Johann

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09-02-2003 03:01 PM  14 years agoPost 2
SteveH

rrProfessor

Texas

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JoHann,

You've hit the nail on the head. There's only so much power in the tail rotor system and if you speed the rotor head, the tail rotor speed increases by a factor of about 5, giving it much more power. Additionally, you can run longer tail rotor blades to increase the power in the tail. Another thing you can do is add the Tripple Bearing tail rotor upgrade, which spaces the blades farther out, adding additional power to the tail. By the way, this is a very desirable upgrade for the Hawk. Hope this helps,

The government cannot give you anything without first taking it from someone else.

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09-02-2003 03:06 PM  14 years agoPost 3
ppljr

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Dallas, TX (Grapevine)

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Headspeed

Rawlie,

I think you may be right about the lower headspeed. I found that when I cranked mine up to 1850-1900 this livened up the helicopter. The lower headspeeds might be fine for a larger helicopter, but I personally wouldn't run any less than 1650. I run woodies, so my upper limit is in the 1900 range. A friend of mine has a Freya and he is running into the same problem. I keep on telling him that his headspeed is too low. He doesn't do any serious 3D, but his tail will wag or lag behind in a hard banked turn when he is cranking the cyclic. Just my $.02.

Pedro

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09-02-2003 03:37 PM  14 years agoPost 4
Rawlie

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JHB

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Steve/Pedro

Thanks for your responses, sometimes its just good to get some additional opinions

Steve, I will look into that triple bearing upgrade you mentioned.

Soft landings,
Johann

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