haasjj

I'm having a new problem with my new setup. I was out trying to do a flight check today with my new X9303 radio and my not new trex 450. The problem I am having is with the Futaba 401 gyro, after skids up the heli would start tail wagging quite a bit to. So my question is, what the #*$@ is wrong? Is there a certain distance that the receiver and gyro need to be apart. Before I get the common answer of check my gyro rate, I did and rechecked everything else 3 times and still was having the problem. The last time I flew my Trex a couple months ago everything was fine the only thing that changed was the new radio and receiver. I also setup and hovered my Raptor 50 today and everything was ok with it I had no tail wag problems. The only thing I can see that might be a problem is the second receiver, it is mounted on top of the metal block where the tail boom goes in and the gyro is mounted below it with a Micro heli lower gyro mount. So could this be the problem with the second receiver and the gyro so close or is it something I am over looking?

Pics below of receiver and gyro mount.

Cleared2Engage

Drop the Gain value and see if that fixes it. If you're using a new radio the values for HH and rate will differ between most brand radios.

haasjj

Same radio company and almost the same radio I went from an XP 9303 to a X9303 I droped the gain down to just above rate mode but still in HH and it still wags. The rate and HH mode in both radio's are the exact same, as a matter of fact I was at 75% with my Raptor and no problems while I dropped the TRex down to 55% and it still waged when before I was at either 75 or 80%.

tippy

The distance from your t/r linkage attach point (on the servo arm) to the axis of the servo arm affects the numbers in the TX.

If the two attach point distances are different (from one heli to another) then this "mechanical" gain difference will affect the numbers in the TX.

Try moving the attach point closer to the hub to reduce your "mechanical" gain ...

haasjj

That is why I am having problems, no mechanical changes were made to the heli in between the old radio and the new one, and everything was working fine then. This trex isn't new just the radio and receiver so why would everything be ok with my XP9303 FM radio and now I am having a problem with the new 2.4ghz system. I knew these responces would come up but that is something I tried to explain in my original post the ONLY THING THAT CHANGED WAS THE NEW RADIO AND RECEIVER
and the new radio is almost the same as the old.

haasjj

Just a quick update on this post.

I was on my way thru Billings yesterday and stopped at Heli Proz and talked to one of the guys there and told him what the problem was and asked him what I should do to fix it.
Well as I suspected he gave me an answer in about a minute, and oh boy did that fell like a head slap moment. Well I realised what I did wrong while seting up my new radio and why my raptor worked fine and my trex was wrong. What I did wrong was when I set my trex I didn't set up the gear channel to be used with the D/R or rate gain for my gyro, I set it under the gyro sensitivity. The reason I didn't think of that was because I have always used 7 channel receivers with my heli's and with the new radio I used a 6ch for my trex so it doesn't have a Aux2 channel. So I had done most things correct but wasn't thinking about the channel selection being wrong, which confused me when I was setting things up because when I fliped the switch the tail rotor was going back to "center" as it should but the rate was still at 100% because I never set the rate on the gear menu on my radio.

Well thanks again for trying to help. I'll let you know if it did fix the problem, I didn't have time to put my heli back together and try the fix as of yet but I'll have time this weekend.

VinceHerman

Haasjj,
Thanks for posting back the solution. This is a huge benefit to all future readers researching similar situations.
Glad you got your heli fixed!
Vince

haasjj

Well I did a better explaination in a different thread I'll link it below so if anyone needs some help you can check it out.

http://www.rcuniverse.com/forum/m_6933886/tm.htm

haasjj

OOPS wrong thread dont respond