Loosing tail gearbox grease

[brunobl]

Hi All,

I am in the process of runing in my Spectra's 231PUH engine. Got 10 flights and a total of 1h 50min on it.

Today I found a bit of grease on the outside of the tail rotor gearbox but I wasn't sure how long it took to get that way, so I decided to clean it off and fly again to cotrol the amount of leak over time.

The picture shows the gearbox seen from the right hand side, after being cleaned and then after 25 minutes of subsequent flying. At this rate I will need to replace the grease pretty soon (if not already needed).

So, here are the questions:

1. Is this leakage normal? If not, what may be causing it?
2. Should I immediately top off the grease?
3. Do I have to remove the gearbox to refill the grease? I have read about a "grease filling hole" in the forums but I can't find it.

All thoughts are very welcome.

[ClayK]

Mine leaks only when there is excess grease. Looks normal to me (like mine), just add some more to the box after 20-30 more flights.

[sookainian]

Sorry to change topic abit,

Can we use the grease for Stratus open tail gear box ? or the open tail gear box dont need to be grease ?

[ClayK]

I don't use grease on the open box.

[ka6fty]

I have read about a "grease filling hole" in the forums but I can't find it.

Remove the bracket that the T/R belcrank is attached to. There you will find "the hole"

[brunobl]

Thanks for the replies guys, will periodically refill with grease.

[DavidH]

That is normal. I add a little grease about every 50 flights. When you add grease it will seep out again in the same place for several flights.

David

[rbort]

Hey Bruno:

How is the heli treating you? Sounds like you are enjoying it less the grease thing. Incidentally, what grease are you using? Some greases will come out more than others. But yes in general they do leak out some when overfilled and then seem to settle in with less leakage. You can add some every so often and as David said it will releak some but that is OK and normal.

By the way, did you get that generator top plate? It should be there any day now if not arrived already.

-=>Raja.

[Fox222]

brunobl,
When you get ready to replace the output shaft bearings, replace them with rubber seals. You want have to grease near as often and it’s a lot cleaner.

[DavidH]

Problem with the rubber sealed bearings is they don't turn as freely as the steel shielded bearings. That is the downside to the rubber sealed bearings.

David

[Fox222]

They loosen up after a few flights. I used to do this on the Pro 2K and S.E.'s. There is less drag then you think. But I would only use them on the output shaft so it only 2 bearings with rubber seals.

[DavidH]

Yeah I tried the seal bearings. With the steel shielded bearings the rotor head would free wheel on the bench when the wind was blowing slightly. With the sealed bearings I never saw it do that and I had the sealed bearings on the gear box for couple hundred flights. Grease would seep thru those also.

David

[Fox222]

I am not having that problem at all. One of my Stratus is a conversion with closed box (and rubber seals) and I just checked it against the open box. If there is any difference I can't tell. And if over fill the gear box it will leak even with rubber seals. It only needs enough to keep the gears covered with grease. Mine still has a little leak but alot less then with the sheilded bearings.

[brunobl]

Hey Bruno:

How is the heli treating you? Sounds like you are enjoying it less the grease thing. Incidentally, what grease are you using? Some greases will come out more than others. But yes in general they do leak out some when overfilled and then seem to settle in with less leakage. You can add some every so often and as David said it will releak some but that is OK and normal.

By the way, did you get that generator top plate? It should be there any day now if not arrived already.

-=>Raja.

Hi Raja,

The heli is everything I wished and then some! :D
Its appearance at the field really stirred things up. A few modelers here have wanted to experiment with gassers before, but they wouldn't want to be the first to try. Last weekend I was called a "pioneer", haha.

The grease thing scared me a little because I didn't know it is normal. I'll be careful not to let the gears run dry and all will be OK. Like I said the other day... I'm learning a little step at a time with this new machine.

I used a general-purpose mineral-based grease. I didn't find anything in the manual against using it in the tail rotor gear box, and I thought it would let the gears run a bit more free than the molybdenum type that I used elsewhere in the heli.

I'm still flying without the canopy as I am not quite decided on the paint scheme. I'm avoiding the firery style as my Raptor is already like this and it is too common at our field. I think I may settle for some kind of solid + stripes, simple stuff. I'll post pictures when it is done.

The top plate isn't here yet. Should arrive any day now. Thanks for asking!

[kthane]

Wouldn't use any grease that is too runny. Gears will sling it off in a hear beat. It isn't nesessary to pack the gearbox. Syringe comes in handy here. Just put enough in there to quiet the gears. Don't let it cake up on the t/r shaft or your gyro will hate you.

[brunobl]

Don't let it cake up on the t/r shaft or your gyro will hate you.

Ouch! :lol:
We know what may happen next, if the gyro comes to hate its owner!

Thanks for the tips.