HELP WITH RETRACTS!

[jnm]

Hey all,I have a T-rex 450 that I have put a Bell 222 fuse on and I am having a problem with the retracts supporting the weight of the heli.
I need some help on this. I tried using a Hitec HS81 servo which is a larger size micro,but it seems like when the retracts are down the servo will not support the wait of the heli,when I put the retracts down and try to set the heli down sounds like the gears are going to strip and the weight of the heli starts to push the servo arm forward. The retract servo that I have is to large and I can not fit it in the space I have to. Should I maybe try a micro servo with metal gears? Any help at this point would be greatly appreciated. Really want to fly this!!
Thanks

[flying 442]

I am not a pro at this, but have looked into it. It is hard for me to tell by looking at your picture, so I should just tell you what I've seen. The servo should ONLY be there to MOVE the gear and not hold it's weight. I believe the gear should be set up so that if you removed the servos the heli would still be sitting on the gear. I hope this makes sense.

In my poor drawing, you see the pink gear support holds the gear so you can take a hard landing. The black gear wire rests it's weight against the pink support, not stressing the servo. The red servo only pulls the lever to move the gear up when ready.

In the second shot you see one that could be bought from Helihobby.com that would work in the same way.

Just do a web search on retracts and you'll see many ways to do the same thing. You should be able to fix the ones you have with very little work.

[brettlw]

You should use a retract servo. A retract servo locks at the end of it's travel so the motor isn't trying to take the load. A standard servo is always running trying to stay in the position it was sent to.

[slope-nz]

jnm,Lots of good advice so far. For my two cents worth,A retract servo operates on a 180 degree motion,you should have the output arm of the servo arm parallel to the push rod from the retract at the end of each rotation cycle. this will lock your gear with out any electral load. I hope that I havent made it harder sounding than it really is. Randy AMA 16732