250 pro dfc (TT) Tail blades not turning with main gear if i resist them with finger

[aussiefly]

Hi guys is this normal? Trex 250 pro dfc torque tube. How much force should be required to keep the tail blades in one spot as I move the main gear? No issue in flight (so far) but I can do it with one finger. If i hold a littleI see the main gear is still turning the tail gear directly on it, but the umbrella gear just above (the one on same shaft) is not turning , so looks like slippage is happening between those 2 gears somewhere. Is this expected?

[nflanagin]

Never, replace the umbrella gear.

Look for threads on JB Welding the gear on. Once it the pulley gear shaft starts to spin in the gear, your going to lose the tail soon.

Besides the design flaw, I think a combination of heat and perhaps oils working up the pulley gear shift, cause it to loose grip on the pulley shaft. You'll see what I mean when you pull the gear, and pop off the umbrella gear from the shaft.

[navigator2011]

Well, I am surprised that you have "no issue in flight." The gear you see slipping should not be slipping. You'll either have to find a way to lock the gear in place, such as suggest above, or convert to a belted tail system. After fiddling around with the TT gears for quite a while, I just converted over to the belted tail and I love the results. There are several thread around here that explain how to convert to a belt and what parts to purchase.

[gimbleguy]

Originally Posted by navigator2011

Well, I am surprised that you have "no issue in flight." The gear you see slipping should not be slipping. You'll either have to find a way to lock the gear in place, such as suggest above, or convert to a belted tail system. After fiddling around with the TT gears for quite a while, I just converted over to the belted tail and I love the results. There are several thread around here that explain how to convert to a belt and what parts to purchase.

+1 on Belt Conversion

[aussiefly]

Thanks guys, I might look at belt conversion after first crash.

As for securing the umbrealla on the shaft I have some pretty strong super glue (Gorilla brand) that I used to put on the pinion on motor which hasnt failed . That should do it? Or I need something like the JB weld?

[nflanagin]

Give it shot. Ive only used jb weld, which is just a high strength 2 part epoxy. Make sure you put the glue on the inside of the gear, I use a toothpick, and not the pulley shaft or you will end up with glue on the bearing.

[DWill]

Originally Posted by aussiefly

Thanks guys, I might look at belt conversion after first crash.

As for securing the umbrealla on the shaft I have some pretty strong super glue (Gorilla brand) that I used to put on the pinion on motor which hasnt failed . That should do it? Or I need something like the JB weld?

If you want it to work well, and have confidence it will stay on use JB weld.

[Skidoojoe]

Originally Posted by aussiefly

Hi guys is this normal? Trex 250 pro dfc torque tube. How much force should be required to keep the tail blades in one spot as I move the main gear? No issue in flight (so far) but I can do it with one finger. If i hold a littleI see the main gear is still turning the tail gear directly on it, but the umbrella gear just above (the one on same shaft) is not turning , so looks like slippage is happening between those 2 gears somewhere. Is this expected?

Hah got same problem just noticed yesterday buy not problem in flight

[aussiefly]

Originally Posted by Skidoojoe

Hah got same problem just noticed yesterday buy not problem in flight

Ya i just put a bit of gorilla glue on it and it has held since. Some guys suggested using epoxy but te gorilla glue is holding for me anyway - I do a check every now and then.

If its not a problem in flight its up to yourself whether to put in the effort to fix it - i'd say it would be a gradual loss of tail authority rather than a sudden change but I'm no expert.

[aussiefly]

Well turns out the gorilla glue wasn't strong enough

Tail gave on me during inverted flight (lucky it didn't hit me). I hit throttle hold about 2 seconds before impact - first thing I checked was holding tail blades while turning main gear and sure enough it turned without any resistance! Then I could see the dried layer of glue seemed to have come out of the shaft hole on the top of the umbrella gear forming a sort of circular layer above (outside) the gear. Grrr! - it seems the only damage done is the main blades (plastic ones) - so might have been lucky. I *think* the feathering shaft and main shaft are still straight - hard to know without taking them out which I don't think I'll bother doing this time.

For anyone with this issue - go with the advice above and use epoxy and not gorilla

I have now epoxied the gear on to the shaft. Hoping that holds.

[dr dremel]

Originally Posted by aussiefly

-snip-
I *think* the feathering shaft and main shaft are still straight - hard to know without taking them out which I don't think I'll bother doing this time.
-snip

You can check the shafts in situ, for the MS you can spool the heli up (without blades) and look at the head button from above. The screw hole in the middle should not get blurry, but remain a perfect circle.

For the FS remove blades and turn the shaft bolt on one grip. As this spins the FS, the opposing blade grip should not begin to move up/down or side to side. Sometimes hard to see, easier to feel with one thumb touching head block and blade grip.

Maybe not as accurate as rolling the shafts on glass, but this has worked for me since the mcpxs.