Broken Wings

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An interesting read...


http://www.aeroslave.com/Greaser.pdf

freakingfast

My Feedback: (3)

Thank you for posting this!

Broken Wings

My Feedback: (20)

I would think that you could just tap a hole and use a screw/washer to plug it without having to go through installing a pressure fitting and making a plug. The syringe is one of the monoject 412's with the long curved end. I think a small 4-40 socket head cap screw would work and you wouldn't have to worry about the plug coming off in flight.

It's a cool idea...

w8ye

My Feedback: (16)

I've played around with using moly grease in model engine bearings.

The grease is immediately expelled from the bearing on start up. It then stays in the nicks and crevices for a short while until the heat and model fuel/oil dilute the grease and it is expelled. After a ten minute run, you would be hard pressed to find any evidence of grease having ever been there.

The grease doesn't hurt anything for it would be expelled from the bearing before you could get the plane in the air.

Broken Wings

My Feedback: (20)

I've adopted the Hobbsy method of using Marine Fogging oil in a spray can. The "CRC Engine Stor" comes out like shaving cream. I just rotate the prop and go through the carburetor/crank with the thin red tube and give it a shot after I'm done using the engine.

pe reivers

Go gas. There is only one way!

Broken Wings

My Feedback: (20)

No...

SrTelemaster150

Too much wieght & vibration for so little power. Besides, they're mostly 2-strokes & sound like crap.

4-strokes running glow fuel on spark. Now there's the ticket.

Turk1

If fuel have castor then no need to grease at all.Those bearings then only under trauma risk of uncontrolled earth meetings.So no grease can help then.

Sport_Pilot

Unless you are using a pipe I do not understand how nitric acid is getting into the bearings. Evenwith a pipeIdo not think it is significant. Nitromethane is noted to be non corrosive for both steel and aluminum. Methanol on the other had is corrosive for aluminum and asorbs water which is corrosive for all metels exceptgold, some more than others. I submit that the corrosion they are sucessfully avoiding is from methanol and moisture, not nitromethane or nitric acid.

aspeed

I am not sure about the Nitro being non corossive.  We used to run 80% nitro and the steel piston cyl. would be stuck together overnight sometimes from rust.  When running 80% methanol with castor (FAI fuel) it was never a problem.  I never used an after run oil under 15% nitro and have had no rust problems.  I am not sure about this grease fitting thing either.  Just another leak to bite you later on.  It  could double as a pressure fitting with proper placement though.  I have never seen a pressure fitting from the front of the motor before and don't think there is enough meat on the casting to do it right,  I always dribble a bit of fuel on the front bearing (plain bearings too) before I run a motor to make sure there is no dried oil (grease) in it.

Sport_Pilot

Ntromethane does not cause rust.  However the nitric acid from burning it can.  I do not see how you can get enough nitric acid in a crankcase to be critical, especially in an unpiped engine. 

Part of the problem you had might be the oil.  You cannot use castor oil with 80% nitro as it will not mix.  So the low or no castor oil may have been the culprit.

aspeed

We used Klotz with the nitro, and castor with the methanol because we had to. We couldn't source nitrobenzine and stuff like that for the high nitro stuff so we didn't use it. Normally the tank is run dry so there is no fuel puddles inside the motor to soak up moisture. The methanol motors were piped and the nitro ones were about 50/50 piped and unpiped. Supertigers, Rossi's Cox .049's and such. Castor wasn't added then because the feeling at the time was that synthetic was better. I do add some now for insurance, but rule changes stopped the higher nitro fuel anyway.

earlwb

I could see that as being useful for the front bearing, if it is a sealed type, but if it is sealed then the seal blocks adding more grease. The rear bearing would need a shield or seal to help keep the grease in too. But it is also blocked by the shield or seal. So I guess you have to do something creative there with the shields and seals to let grease in somehow.  I suppose for the rear bearing you leave a shield in place on one side and remove it on the other where you would install a grease fitting or something. I suppose the front bearing would have a similar setup on it too.

But there is a RPM limit to the bearings with grease in them. Where beyond some certain RPM limit the balls start to skate and not roll anymore. Plus the grease has more drag to it than oil does, so it would likely cause a RPM drop for performance too.

But since I only run no or low nitro glow fuel in most of my engines and my fuel has at least, some castor oil in it, I haven't really had any bearing problems with my engines. Heck I don't even bother with after run oil either.