500 Trex 500 tail belt tension

[Derek]

While I'm waiting on the parts for my 450 to show up, I took my 500 out for the first run of 2014. The tail was wagging all over the place but it wasn't a consistent wag. I set it down then tried the hover again. The tail had the inconsistent wag. Hmmm, I set it down again and powered everything down and brought it inside for inspection. It didn't take me very long to see that the tail belt was very loose. Belts stretch..I understand that. I did order 2 brand new belts (one for immediate replacement and the second belt as a spare) but would I be ok to loosen the boom bolts, pull the boom out a bit to tighten up the tail belt, and fly? Or should I just wait for the new belts?

I just loosened the boom bolts and pulled the tail to tighten the belt. The boom is now less than 1/4" from where it was originally at. I know there is a slot in the tail boom that fits on a knotch inside the tail boom casing. This slot keeps the tail boom from rotating. If I were to tighten everything up and go fly, what do you think the chances of something going wrong?

 

[murankar]

Not much unless you plan on beat the shot out of it. It should be fine for light sport flying, anything more i would be cautious. The setup is designed to be adjusted.

Sent from my LG-E980 using Forum Runner

 

[danhampson]

i would just fly it. Like Uri said they are made to be adjusted, and things like ambient temperature can play a part.


last week it was about -2°c and the belt on my protos was quite tight, the after the flight and a hour or so in the house i remembered to have a look at the belt tension and it was normal.

I check the tension on mine every 10-15 flights or if there have been extremes in temperature between flights or if i cant remember when i last checked (memory ism't what it used to be)

 

[Lee]

Just spin it by hand and check for any wear and tear. If it looks good, then go fly. Tail belts can be run pretty loose.
A good way to check is to hold the tail assembly and gently try to turn the head. If it slips, its too loose, if not then it should be good to go

 

[pvolcko]

Are you sure the adjustment didn't move? If the belt did stretch, just readjust and fly. Only need to replace if you're out of adjustment room or the belt is frayed, split, or worn.

 

[Derek]

Yeah, I'm sure that the adjustment didn't move. I have one of the tail servo mounts as my reference marker. The distance between it and the boom case is the same as it was when I adjusted it when I replaced it last year. The 500 has sat on a shelf since October '13. I've spun the gears so that I could inspect the belts condition. It is not split, frayed, nor worn. Since I've got nothing better to do, right now, I'll go ahead and loosen up the screws and I'll double check for more boom adjustment. I just don't want to adjust it rearwards too far so that the notch won't hold.

Perhaps my 500 is still flyable as it is but I do have two new belts coming. I should be able to get them Tuesday.

Thank you for everyone's input!

 

[Derek]

Ha! I guess I was just being overly-cautious. I loosened up the couple screws that hold the boom tight to the boom block and pulled the belt tight again. In all honesty, I only pulled the tail boom less than 1/8" and the belt is tight once again. It's amazing...that small amount of adjustment could take up so much slack. Don't get me wrong, the belt wasn't so loose that it was "flapping in the breeze" but it was far from tight and surely seemed to be enough to confirm my suspicions of "slippage."

 

[danhampson]

Glad you've got it worked out. I had nothing but problems with a couple of 450 clones that had belt drive tail, then I go and buy a Heli with all the drive train belt driven lol.

Happy flying mate.

 

[pvolcko]

Will be interested to see if this actually solves the wagging issue. Have my doubts, but if it was loose enough I could see it being a cause.

 

[Virtibird]

Instead of pulling the boom out of the block to make the adjustment I cram the boom in as far as it will go and make the belt adjustment at the tail case. Just wrap the boom with a piece of shipping tape, make the adjustment and tighten up the bolts. Also it's much easier to do with entire boom assembly out of the airframe. I never have any issues with tail belt adjustment doing it this way, it's just a little harder to get everything lined up, but once it's done it's done.

 

[Derek]

Please note that this thread is almost 1 year old.

I've not had any troubles in a very long time, but thank you for posting!