Stripping belt drive gear - any ideas

[Mikej]

Guys,

I'm hoping for some more help please - heli is a Shogun V2. I'm fairly new to this still, so during my first attempted flight I had a bit of a tail strike that knocked off the tab that the tail pitch control lever pivots on. I glued the tab back on - seems OK.

I was also unhappy with the standard brushed motor - I could see it sparking plus the (non-standard) ESC kicked in really hard. So I initially tried a motor that I have for a Trex, but the pinion was not long enough and only went half way up the gear drive for the belt to the tail and stripped the gear . So I bought a new gear and bought a new Brushless motor and ESC, fitted this but was getting aweful vibrations between 1/3 throttle and 2/3 throttle - this disappeared at high revs, but was really moving badly mid-stick. Also the boom was getting warm in the middle, so my guess was that I had twisted the belt when fitting the new gear. I then removed the boom got the belt straight, put in half a twist to get the rotation direction correct and tried again.

I am testing this without the main blades on - just the paddles, so I span the motor up again - still got vibration, but not as much so I ran it like this for a while and then saw a flurry of snow coming from the motor area as the pinion shredded my new gear .

Now I'm completely confused (I've got a third gear on order to ruin later ) - my only guess is that I had my belt too loose and it is setting up a strange oscilation of the belt and rubbing on the boom and certain speeds. Any other suggestions (this doesn't really explain why I am stripping the gear shaft though).

Oh and when I had the boom off I ran the motor up - no vibration at all so it is definitely the belt / tail that is causing this - I had looked closely at the tail drive shaft and it lloks straight.

Any ideas gratefully received.

Cheers,

Mike.

[Jungle Bob]

Hi Mike
New boom time mate, your earlier 'tail' strike could have twisted or bent your boom slightly which explain all of the symptoms you have. Check your boom to frame connection and check your frame for distortion or cracks. You may not be able to 'see' the boom bend but get it off and roll it on a flat surface, any slight bend will show up then. Don't give up, my V2's (got two of them) fly very smootly and I luv em to bits

[BlenderPilot]

Mike,

if you test the drive train without main blades, you will get a lot of vibrations as the whole drive train is almost resistant free and reaches a lot higher RPM than with the blades on. Always test with all the blades on!

I had a shogun V2. Great heli, learned to fly on it from scratch.

- Check that the tail boom is straight,
- never motor the drive train if the gears are not leveled between each other. Gear, or should i say teeth coverage, must always be 100% or the forces on such a small surface will destroy the gear.
- never repair the control system parts on your own. If your repair on the tab fails, you will be very sorry.
- try balancing the blades (finless has great instructions on that). My vibrations never occurred again after i did some balancing on mine. The vibrations come back as you spool down too, don't they?
- vibrations may occur if the belt is too tight. Loosen it up a bit. If you run the belt to tight not only does it vibrate, it takes a lot more power from the motor to run the same RPM.

[Mikej]

Originally Posted by Jungle Bob

Hi Mike
New boom time mate, your earlier 'tail' strike could have twisted or bent your boom slightly which explain all of the symptoms you have. Check your boom to frame connection and check your frame for distortion or cracks. You may not be able to 'see' the boom bend but get it off and roll it on a flat surface, any slight bend will show up then. Don't give up, my V2's (got two of them) fly very smootly and I luv em to bits

Thanks Bob - I tried that, the boom rolled fine so I am pretty confident that the boom is straight - but thanks for the suggestion, gratefully received.

Cheers,

Mike.

[Mikej]

Originally Posted by BlenderPilot

Mike,

if you test the drive train without main blades, you will get a lot of vibrations as the whole drive train is almost resistant free and reaches a lot higher RPM than with the blades on. Always test with all the blades on!

I had a shogun V2. Great heli, learned to fly on it from scratch.

- Check that the tail boom is straight,
- never motor the drive train if the gears are not leveled between each other. Gear, or should i say teeth coverage, must always be 100% or the forces on such a small surface will destroy the gear.
- never repair the control system parts on your own. If your repair on the tab fails, you will be very sorry.
- try balancing the blades (finless has great instructions on that). My vibrations never occurred again after i did some balancing on mine. The vibrations come back as you spool down too, don't they?
- vibrations may occur if the belt is too tight. Loosen it up a bit. If you run the belt to tight not only does it vibrate, it takes a lot more power from the motor to run the same RPM.

Thanks blender - I'll try again with the belt a bit looser when I manage to get another gear shaft - I've now stripped 3

[Mikej]

Update - I have got another drive gear (3 in fact just in case) and have re-set the belt a bit looser and it's working a treat , I also re-set the meshing of the motor pinion as I think that may have been a bit tight as well. I have put the old brushed motor back in which smells horrible and gets very hot - but I'll stick with it for a while until I am 100% happy with the set-up. I think what was happening was that I had the belt too tight, there was friction and resitance to turn which was why the gear was stripping - hopefully when I put the brushless back in it will be Ok as I have not heard of anyone else having similar problems.

But I'm happy again now

Cheers,

mike.

[BlenderPilot]

Glad to hear that Mike!

Happy flying!

[clear4takeoff]

I never had gear stripping problems, but the V2 is always a compromise with the "stacked" gears because one or the other is always too loose or too tight. I would set the mesh with a piece of paper inserted between the pinion and both gears, then the minimum backlash is never too tight, if that made the other a bit loose, so be it. I ran a Park 400 4200kv with an 8t pinion, and many many flights.

cheers