700 stripped main gear

[Made2Fade]

Hi guys...

Went to the field flying today with my TRex 700. Its a 7/8 flight old model and is basically almost brand new. Engine is just starting to show some life Anyways... half way through the first flight of the day i landed for a short breather and to warm my hands. Upon spoolup i heard a strange sound i was unfamiliar with (later to find it was probably one or 2 teeth coming off the main gear). Anyways went into idleup 1 and took her up higher. About 50 foot up and that sound got louder and the heli started to vibrate badly. I knew at that point that the main gear had stripped as the sound was pretty obvious. Got the heli down without any problems or bumpy landings anyways so that was okay as it could have been far worse. Upon inspection this is what i found:-




Questions are why has this happened? and what gear shall i replace it with (dont want this to happen again)? Any other info most appreciated. For anyone that says this isnt an issue with the 700 then heres your proof. As far as i was aware this heli was setup perfect. I made 100% sure it was... so whats going on?

Cheers
Lee

[Tim Procter]

As far as I'm aware there is an upgraded main gear for sale now Lee.

Had lots of flights with mine and never any trouble.

[machasm]

As far as I'm aware there is an upgraded main gear for sale now Lee.

Had lots of flights with mine and never any trouble.

Is that with or without the upgraded Gear Tim?

[Tim Procter]

Without Adrian. Standard gear.

[mattie-lodge]

I have had least 60 flights on mine with no problems, however there is more and more talk about these gears failing. Raptorheli2 has come up with a possible fix of adjusting the mesh.

Perhaps he will chime in

[Made2Fade]

Thing is though its not as if the mesh was'nt perfect on this one. In fact i know it was meshed correctly... i think it may just be crap quality gear. Im thinking about grabing the upgraded gear but its like 26 quid

Cheers
Lee

[Sao]

There are a few possible causes

1. Cold weather causing the main gear to shrink, the new align gear is slightly larger to help with this.

2. Plastic clutch bearing block wearing and developing a slight amount of play, there are some metal blocks being made in the US

3. Frame holes drilled incorrectly.

Solutions
A: Buy either the slightly larger align main gear or the delrin machined one from micro heli.

B:Fit a metal clutch block

C:Buy the gear adjustment set from one of the US retailers, think its grandRC Edit: No it's heli daddy http://www.helidaddy.com/product_p/hd70003.htm
You remove the lug from the clutch block and elongate the holes in the frame and fit some carbon plates to make sure the top and lower engine mount holes line up perfectly.

D: Do A,B and C

[Tom Burgess]

Done 3 gears in on mine, pain in the ass!

Waiting for the microheli CNC main gear to arrive from fast lad.

Tom

[Made2Fade]

Think ill go with the micro heli upgraded gear as its easy enough. Doubt its the clutch block because the helis not that old. Unless they really are total crap blocks full stop mind. Dont fancy modding frame holes etc. If the microheli gear doesnt hold up then ill go down the route of the adjustment set. What a pain in the ass this is though. Gotta feeling the snow on the ground and general cold weather didnt help here.

Cheers
Lee

[raptorheli2]

i have moved the mesh on mine. very simple to do. just get 10 new bolts and move it, there is NO modding required other than fit new bolts. i've also just reviewed this which should in theory fix it-

http://www.trextuning.com/blog/?p=886

cheers

[robgt]

I think it could be luck of the draw on the main gears. I had one gear fail after more than 20 gallons through the heli (it failed on the Friday funfly at the 3D Championship weekend last year).

Some seem to last for ages, and others, not so long??

Glad the heli's in one piece mate
Cheers,
Rob

[Made2Fade]

i have moved the mesh on mine. very simple to do. just get 10 new bolts and move it, there is NO modding required other than fit new bolts. i've also just reviewed this which should in theory fix it-

http://www.trextuning.com/blog/?p=886

cheers

Is there an internet site/shop where i can order this? Think ill give it a spin, looks kool regardless. Probs chuck the upgraded microheli gear on it too when it arrives.
Rob i was kinda thinking the same thing... alot of the Align parts seem to be hit and miss these days Bloody shame the 700's gonna be out of action for a while, was really starting to get into it lol
Cheers
Lee

[robgt]

Yeah, when it works well it works really well - I thoroughly enjoyed mine when I had it

Cheers,
Rob

[Sao]

For the metal clutch block shoot Miro an email at ForAxis@gmail.com

Heres the thread on freak http://www.helifreak.com/showthread.php?t=114423&page=2

[raptorheli2]

i think your bang on rob. it is down to pot luck mostly but it's based on a few things.

1. how accurate the holes are on your frames (it's align, say no more)
2. the clutch block is made from stilton
3. the main gear should be mod 1 which i doubt will ever happen. they would have done it instead of making the new gears larger.

cheers