Lower frames breaking

[Lejon]

I have an older Min Air Gasser with the aluminum lower side rails. About once a year I seem to break one about 2 inches from the front. It does not seem to be from a hard landing or a wreck. I do not think there is excesive vibration and the skids (until the break) are pretty solid (smooth).

Is there anything that is more than likely the cause and is there anything to do that will reduce or prevent this?

Lejon

:shock:

[ddavison]

I had the same problem. I bought the CNC lower frame rails for the Graphite SE glow. Sandwich them to the outside of stock gasser frame rails and drill through all the holes and mount them with all the bolts some holes may need a little tweaking. They will not break any more.

[Lejon]

Since it only happened once or twice a year I was not too worried with it. I will get something like that setup and go for it.

Thanks


Lejon :)

[rbort]

The answer is JR rubber landing gear dampners. Install the gear on those and then to the frames and the lower frames will never break again, even if you crash. The dampners give and rip (in a crash) and the gear and frames are saved.

For a picture of them, take a look at the front page of my website (link below). You can get them at Rick's RC.

-=>Raja.

[flyinfool]

I had the same thing happening.
Even though there was no visible buzz anywhere it was still a vibration issue.
Check the engine, fan clutch and the rest of the parts spinning at engine RPM for both balance and run-out.

[Lejon]

After changing out several items and not seeing any real changes I am curious if anyone has seen this.

I have the needles set around 1 3/8 L and 1 1/2 H. I start the heli and get it into a hover. Then I do a few climb outs (only 30 to 50 ft) then back down. When I lower the throttle the heli turns 30 degrees counter clock wise and descends. Then when it is back in a hover it starts to increase the rpm and goes through a period of vibrating as if it were out of balance. Then within seconds it settles (at a significantly higher rpm) I would say it goes from 1450 to 1700, when it reaches this higher rpm it is very smooth and runs normally. If I take it up and fly around it will vibrate when ever it transitions and then smoothes out again. It is as if the engine were coming up on a pipe. It does this with both the can and the Bison muffler.

Any ideas?

Lejon