C BOX PLAY WHEN HOT

[Graham Mac]

C BOX 582 ROTAX NO STARTER ON IT.
Has anyone got specs on permissable or acceptable play on the movement of the propellor shaft (that you bolt the prop on and that goes right through the box and is visable on the exit to the rear of box.)it moves forward and back.
im not refering to side to side play as in direction of prop rotation.
I have noticed AFTER FLIGHT that when the box is warm/hot the play by pulling the prop on the hub towards and away from yourself(front and rear of craft) moves forward and back about 5 mm
When the box is cold pre engine start the play dissapears and is normal.no play whatsoever.
has anyone expierenced this play on a hot box????
Should i be worried of failiure in flight.????

[Alkemac]

The play is in yer fingers laddie!

Give that man a Bells

[Graham Mac]

The play is in yer fingers laddie!

Give that man a Bells

Hey Alkemac...................sounds like youve had 1 or 2 "Bells" too many.
The question is have you checked a hot box?
i dont think many here have.
Mabe its time to check.and have the result published as this is a concern for me right now...and mabe for others.

[Gompou]

Hi Graham
I have a E box
I have check mine after half a hour flight yesterday evening.There were no lateral play as you describe . Around 250 hours on engine and box.
There is also nothing in the workshop manual that indicate that there is suppose to be any play.

Gompou

[Duck Rogers]

Graham.........that prop flange is held in place by a "mother-of-a-nut" on the inside and it runs through a large carrier bearing which in turn is held in place by a large ring "washer" that is held to the gearbox case by I think, 4 bolts.
If the large nut has somehow loosened itself, then the propshaft will slip and you'll notice it straightaway.
If the 4 bolts that hold the ring in place are loose, then there is a possibility that the entire assembly could move forwards or back. If the bearing is damaged, there may also be a possibility that it could have lateral play especially when the oil is hot. There are also 2 spacers in the assembly that could be damaged or maybe someone has repaired the box and didn't replace the spacers or replaced them with the wrong ones or even left one out
Either way, there should be NO play, hot or cold.
Have it checked out as soon as possible.

[Graham Mac]

Thanks for the input Guys.
I just find it strange that all is well on no play when cold and play after warm or hot.
Geuss Duck that your advise will have to be taken.
Mabe a new box will be easier.
Anyone with a C box for sale?

[Duck Rogers]

Go remove that box and drop it off at my house..........repairing it is cheaper than a new or used one...

[Graham Mac]

Thanks Duck
You are a real gentleman.
Much appreciated for the offer.
What i know about gearboxes is very dangerous..
Will fly her a few times more and remove.

[Gompou]

Will fly her a few times more and remove.

[Dobbs]

Graham Mac - hopefully you are joking

5 mm lateral play is a whole lot, I would certainly strongly advise that you keep the trike / gearbox firmly on the ground until the gearbox has been given a clean bill of health

[Graham Mac]

not joking.flew her today...with an eye on a place to land and the mag switches to shut her down should the S.H.1.T hit the fan i mean the wing...she is still ticking like a clock.
will have to sort her out sooner than later.

[MADDOG]

Please do not fly it until it has been checked out and given a clean bil of health.

[Graham Mac]

Please do not fly it until it has been checked out and given a clean bil of health.

OK Guys
youve put the fear of God into me now.
I will officially GROUND my aircraft with immidiate effect.
Has anyone else checked to see if any play on a warm/hot box?

[Graham Mac]

Hi Guys,

Coincidentally, a friend of mine recently found a lot of play in the horozontal plane, of the output shaft - the one which attaches to the prop when pushing his plane into the hangar (C box on a 503). Some time later, after the box had cooled down, the play was gone.

On further investigation, he found out that this is something which, although rare, only occurs with the C boxes, and although not expensive to fix, it does require the dis assembly of the box.

The concerning thing is that with a cold box, the play is not apparent, and only manifests itself as the box warns up - not sure if these are the same symptoms which you are reffering to?

Cheers

DobbsDobbs
Found this on another thread......exactly my experience

[Graham Mac]

Go remove that box and drop it off at my house..........repairing it is cheaper than a new or used one...

Hey Duck R
Thanks for your knowlegeable telephonic technical advise on the intricasies of dismantaling and removing the main gear and bearings of a C Box final drive.Hectic stuff.not as easy as it looks without the right tools.
much appreciated.
The beers on me anytime you can make it.

Graham