r90 tail case gears stripped out 3 times

[inkspot1967]

i have a new r90 and i have stripped out 2 sets of tail case gears while trying to just break in motor just hovering ...now on its 3 rd set of tail case gears and i have flown it on some nice and easy flights on 3rd flight with it the tail case gears stipped out in flight,so i did a auto and it wasnt to good at end didnt hit hard at all but it did flop over and cut the boom right off...this thing is a piece of crap...and i took the tail case apart and the gears were stripped out completely...

anybody else have any problems with the tail gears ??????????

[Sar]

The R90 is the same tail setup for the most part as the R60 and spinning at the same RPM's as the R60. I notice you have an Extreme and you probably have good experience working with tail boxes as such. The tail gears should mesh but not be so tight they are notchy, and not too loose either. Are all the bearings in the tail assembly nice and smooth and well lubricated? A bad bearing warming up and then seizing up can cause problems. There are people running these R90's successfully, so I would tend to think it's a problem specific to your helicopter, not the entire line of helis.

[Matthew]

Man I've only lost my gears once. But that was in a crash and I lost the gears in my 9253 with it. I've put my tail in the dirt many times and never had a problem. Is there any binding in your's or is there allot of slop. Those might be the cause of it.

Matthew

[WillJames]

Make sure the gears are meshed tightly enough but as Sar says not binding at all. If they are not engaged good enough they don't last nearly as long. Are they stripped all the way off the gear or is there some teeth still that are halfway ripped off? How are the bearings on gear and also on the TR Output shaft, are they well greased and the tailbox greased well? Do you have any binding in your tr total travel? (Does the slider hit the tailgearbox or the outer limits of travel if you go full deflection with your rudder stick?)

What gyro and gain settings you running?

I have never stripped out a tailbox that did not happen in a crash or tail strike.

[inkspot1967]

the first 2 sets of gears stripped out only some teeth on the gears and some teeth were still there and that was when only hovering...the 3rd set of gears completely stripped out... the bearing seem ok to me and no binding tail moved smooth and free without alot of slop...and friend of mine who has a r90 checked it out and said it was also ok. it flew fine on 2 easy flights with the 3rd set of gears then it just let go while up high....im using a gy502 and my gain is set at 45% i never greased the gears at all it doesnt say that in the manual...my buddys r90 he never greased his either and his has been just fine......

[WillJames]

I'm not sure about the gear greasing it is just what I do with a tiny bid of white lithium grease. It could be I'm doing wrong, but it has worked for almost 2 years. :)

I do the bearings with my greaser then pit a very small amount on the gears.

Odd, something has got to be going on if you have stripped sets while hovering. :shock:

????? Anybody??

[Sar]

Is the main TR drive gear below the primary rotor gear in good condition all of the teeth in tact and not bent/mangled? Are the gears inside of the tailbox in good shape? If one of these are in bad shape perhaps they bind up and the intertia in the TR is enough to strip the gears out? I think that's a bit extreme of a concept though.

When you put the tail boom on the heli, did you push it all the way into the tail block on the main frame? This can put a lengthwise load on the torque tube as it bottoms out in the gears it slides into and can cause uneccesary load on the tail drive system. In the R60 this would lead to vibrations, with only one bearing in the tube the tube could flex a little. With the R90 there are 3 bearings in the tube to minimize flex, so I would imagine it could put a higher load on gears/bearings.

When you install the tailboom, slide it in all the way, and then back it out about at least 1/8th of an inch to help eliminate the problem.

[WillJames]

this would lead to vibrations



Good point Sar. Is your heli very smooth or is does it have some vibs?

[inkspot1967]

both tail case gears were completely stripped out the 3rd time i replaced them and i only had 2 bearing in my tube..thats all it came with...and i believe i did push the tailboom all the way in just figured thats the way it should be,not sure if being alittle lose like that would be good but maybe it couldnt hurt either

[WillJames]

I run 3 bearings on my R90's and they are smooth as silk with no vibration. I do pull out the boom a couple mm's to keep it from tweaking the Torque Tube.

[inkspot1967]

on the 3 bearing these things are so hard to get into the boom how do you do it and what are you using to glue or silcone them in.... :arggg: