12E Main XSMN, T/R, Cuff and Trunnion Oil

[SL12572]

Can someone give me some insight on what would be the best oil to use in a Hiller UH-12E? Long time Hiller operators tell me that the approved oil in the T/R gearbox is junk and in fact attracts moisture. Very few hours after an annual inspection was performed, the T/R gearbox oil started to look cloudy, so I drained and replaced it. I'm hoping to find a solution that I can standardize and run the same oil in the main and t/r transmission, along with the cuff and trunnion. Something that meets or exceeds the milspec and can be legally ran in the aircraft. I appreciate the advice and help.

[Nieuport28]

I have been operating E's in the ag for 31 yrs. We use a mix of 4qts areoshell 100w and 1 pint of STP, in the main trans, TR/GB and cuffs. Change main trans and TR/GB oil every 100hrs, check cuffs when you see a leak or every 100hrs. Do not use the 100w plus, has a slick 50 stuff in it, not good for the free wheeling clutch bearings. 18,000 plus hrs with no oil related problems.

[SL12572]

Nieuport28,

I appreciate the information. What temperatures are you operating in? I'm primarily out of Washington, so it's usually not too cold, or not too hot.

Thanks

[Nieuport28]

We operate in the central valley of Ca. Temps range fron 30-105F. We stop working at 90 if possible, to hard on the machine and crew. The STP is the key, it's no better as a lube than the 100w, but it keeps a oil film on the gears which is what you need for start ups.

[SL12572]

Are you using the STP product called "oil treatment"? Also, what engine oil do you use? It's good to hear from the guys who have been operating Hillers for years.

Again, I really appreciate the information.

[Nieuport28]

The STP is the engine oil treatment. In the engine we use the Aero Shell 100 for the break in, then at around 75 to 100 hrs we switch over to the 100W. Change engine oil every 25 hrs and use the oil soaked air filters and your good to go. Don't put the STP mix in the engine, just in the cuffs and gear boxes.

[CopterDr.]

The Soloy Manual (for those Soloy 12E's) allows the use of Anderol 471, which is a synthetic gear oil, in the Main transmissions, and it is good stuff. It allows for improved oilflow at cold temps, and has a higher load capacity at any temp compared to Aeroshell xxxW oil.