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Old Dec 23, 2011, 12:26 AM
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Fixed my left drifting problem on my DH9104!

Hi just wanted to let others know that I was having big problems with takeoff on my DH9104. It was drifting hard to the left all the time. I thought too myself while I was trying to figure out what was causing the problem that the tail rotar was quite big and out of scale to the rest of the heli and that it might be pushing the chopper to the left while counteracting the spin of the main blades. So I trimmed off about 1cm from each end of the tail blades and now my 9104 will basically hover straight up into the air with very little movment and is a massive improvement!
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Old Dec 23, 2011, 01:24 AM
Crash and learn
United States, PA
Joined Dec 2011
1,605 Posts
And since it comes with an extra tail blade... Sounds easier than the paperclip ""hillbilly-tech link bar" mod in front of swash plate.
http://www.rcgroups.com/forums/showt...y#post18139964

Did you try out forward flight yet and is it sluggish?

I have a DH9104 coming in a few days., and no experience beyond many simulation hours.
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Old Dec 23, 2011, 02:46 AM
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No not yet as its raining outside only inside the house so far. I also tightened up the screw on the link at the rear of the swash plate as tight as it would go and that along with trimming the tail rotar's has helped. Might hurt forward flight though so when I test that ill let u know. As I got it for $57 im not too worried it I stuff it ill just get another one!
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Old Dec 23, 2011, 11:37 AM
Always, against the wind
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United States, IL
Joined Oct 2011
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Quote:
Originally Posted by Ribble View Post
And since it comes with an extra tail blade... Sounds easier than the paperclip ""hillbilly-tech link bar" mod in front of swash plate.
http://www.rcgroups.com/forums/showt...y#post18139964

Did you try out forward flight yet and is it sluggish?

I have a DH9104 coming in a few days., and no experience beyond many simulation hours.
Check this out:
http://www.youtube.com/watch?v=oNnRD...6&feature=plcp
and the rest of his vid mods
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Old Dec 23, 2011, 11:59 AM
Crash and learn
United States, PA
Joined Dec 2011
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Thetis - Thanks. I thought the linkage was adjustable. Now I know what jesterfester78 meant when he said he tightened up the screw on the link.

There was also a mod somewhere where they added an extension to the servo arm to get more linkage movement.

Will watch the other videos in the set you linked.

Decades past I built my own RC transmitter (50.1mHz), receiver, and three servos. And two RC fixed wing aircraft, plus cars and boats. But I have little idea how they do things nowadays. My first RC set used vacuum tubes and batteries were a problem to find.
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Last edited by Ribble; Dec 23, 2011 at 12:11 PM.
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Old Dec 23, 2011, 12:17 PM
Always, against the wind
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United States, IL
Joined Oct 2011
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Quote:
Originally Posted by Ribble View Post
Thetis - Thanks. I thought the linkage was adjustable. Now I know what jesterfester78 meant when he said he tightened up the screw on the link.

There was also a mod somewhere where they added an extension to the servo arm to get more linkage movement.

Will watch the other videos in the set you linked.

Decades past I built my own RC transmitter (50.1mHz), receiver, and three servos. And two RC fixed wing aircraft, plus cars and boats. But I have little idea how they do things nowadays. My first RC set used vacuum tubes and batteries were a problem to find.
According to vid you have to go counter clock wise (unscrew) for FFF and not tighten up - clockwise. Glad it helped you.
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Old Dec 23, 2011, 12:32 PM
Crash and learn
United States, PA
Joined Dec 2011
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I am out-of-date! Used to turn clockwise to shorten the links, but that was for long pushrods. OK, CCW does make the link longer.
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Old Dec 30, 2011, 05:51 PM
Crash and learn
United States, PA
Joined Dec 2011
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DH9104 swashplate adjustment mods

The DH9104 single blade (21 inch diameter) 3-channnel helicopter swashplate pivots forward of the rotor. This reduces the amount of forward/reverse control. It has a fixed distance between the rotor shaft and forward fixed links. But as the swashplate angle changes, that distance becomes less, causing the two forward links to bend back and makes the servo work harder.

The DH9104 also drifts hard to the left.

I tried the "hillbilly paperclip mod" and that didn't work for me.

Swashplate Pivot Fix:

What I finally did was completely remove the two forward fixed links. This moved the swashplate pivot point to the center of the rotor shaft, giving more control with less work for the servo. It also caused a strong forward drift, which I fixed by turning the rear servo pushrod turnbuckle clockwise five full turns (made the pushrod shorter).

DH9104 Left Drift Tie Wrap Fix:

To fix the left drift, I used a garbage bag flat flexible plastic tie wrap. The tie wrap was inserted into the left side square servo hole and back out again below through the oval hole. This caused the top (hole) of the tie wrap to flex outward. The hole in the tie wrap was adjusted level with the turnbuckle, then bent inward and over the (disconnected) turnbuckle. Duct tape in place and trim the bottom excess of the tie wrap.

The top of the rear servo pushrod is now lightly pulled to the left side, causing the swashplate to tilt to the right, negating the helicopter left drift.
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Last edited by Ribble; Jan 17, 2012 at 06:06 PM.
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