Concept 30-srx problems: shaft for pinion gear getting very hot...cause unclear.

[OldSchool]

on the concept there is a clutch unit that meshes with a plastic gear,
connected to a metal (pinion gear...or at least that is what I call
it) which then meshes with the plastic main gear connected to the
mast. After a short flight (5 min) the shaft in the middle of the
pinion gear is too hot to touch. The metal pinion gear is warm.

The two bearings that hold the pinion shaft are smooth as silk, their
insides are lock-tighted to the shaft. The shaft connects to a
rod-within-a-pipe drive which then drives the tail rotor.

Never had this problem before. By the time I take it apart, things
have all cooled down, and everything seems to turn freely. The mesh
between the main gear and the pinion gear is good, but not too tight
(piece of paper will fit inbetween).

Any thoughts or advice is greatly appreciated!!

[Gp]

"OldSchool" wrote:
>
> on the concept there is a clutch unit that meshes with a plastic gear,
> connected to a metal (pinion gear...or at least that is what I call
> it) which then meshes with the plastic main gear connected to the
> mast. After a short flight (5 min) the shaft in the middle of the
> pinion gear is too hot to touch. The metal pinion gear is warm.
>
> The two bearings that hold the pinion shaft are smooth as silk, their
> insides are lock-tighted to the shaft. The shaft connects to a
> rod-within-a-pipe drive which then drives the tail rotor.
>
> Never had this problem before. By the time I take it apart, things
> have all cooled down, and everything seems to turn freely. The mesh
> between the main gear and the pinion gear is good, but not too tight
> (piece of paper will fit inbetween).
>
> Any thoughts or advice is greatly appreciated!!

I've never encountered this problem with my C30, but I would guess that
either the pinion is slipping on the shaft (check the 4 mm grub screws), the
secondary shaft is slipping within the bearings (even though you've applied
loctite), or the tail drive coupling is slipping on the shaft (check the
roll pin). I really can't think of anything else.

Good luck.

Gp
New Market, Maryland

[Beav]

"OldSchool" <OldSchool@here.com> wrote in message
news:sin7evsua2v5incmhfcku08fp6jshcji4d@4ax.com...
>
> on the concept there is a clutch unit that meshes with a plastic gear,
> connected to a metal (pinion gear...or at least that is what I call
> it) which then meshes with the plastic main gear connected to the
> mast. After a short flight (5 min) the shaft in the middle of the
> pinion gear is too hot to touch. The metal pinion gear is warm.

Is this the old aluminium gear or the later steel gear? Anyway, one thing to
do is grease the white plastic gear. Hirobo include a great grease for this
in the shaft drive Shuttle/Sceadu kits so you could get that or use a spray
on chain grease. Either will do a number ofthings. Reduce the noise, reduce
the friction (and the eat) and reduce the wear, but if it's the ali gear,
change it, because them buggers wear out 'til the teeth on the gear go razor
sharp.

>
> The two bearings that hold the pinion shaft are smooth as silk, their
> insides are lock-tighted to the shaft. The shaft connects to a
> rod-within-a-pipe drive which then drives the tail rotor.
>
> Never had this problem before. By the time I take it apart, things
> have all cooled down, and everything seems to turn freely. The mesh
> between the main gear and the pinion gear is good, but not too tight
> (piece of paper will fit inbetween).

Have you tried the paper thing while you hold the heli OFF the bench by the
rotor head? Do it and see if the whole mast and gear sit exactly as they
were doing, or if they "click" up dragging the teeth into tighter mesh. If
it does, correct it with mast stopper positioning.


--
Beav


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