Gearbox oil/lube

[lloydmsw]

What oil or lube should I use in the gearbox between the engine (40) and the mast?

[schluterdude]

none....

the exception to the rule are the old schluter SX81's... they used engine exhaust to lube up the complex gearbox they used.

set the gearmesh correctly and voila... good to go.

[tdswan]

The reason you use none is because the lube would attract dirt and then cause premature wear on the plastic or delrin main gear.

[lloydmsw]

none....

the exception to the rule are the old schluter SX81's... they used engine exhaust to lube up the complex gearbox they used.

set the gearmesh correctly and voila... good to go.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Schluterdude,
Maybe I needed to provide more info about the oil/lube question.

I am attempting to resurrect a Morley Hughes 300 (1/7 scale) heli. If successful, I hope to convert it to electric.

In the instruction manual for the Morley, it states "Pack the gearbox with light grease", then it goes on to say "After approx 30 minutes of running ... lubrication with gear oil before flying sessions."

(See excerpts from manual - attached)

[schluterdude]

unfortunatly, i don't have any experience with the morely line. i've only read about them here and there, and seen some pics every once in a while.

but, from light grease, i would use something similar to bearing grease. in my schluter, i personally use moly grease from the autoparts store in its tailbox assembly.

as far as light gear oil, there are a few options. i would think that it has you add oil because, due to heat, the grease has a tendancy to "dry up" and thus can't really move around. i do put a few drops of tri-flow in the oiling holes of my tail box before each flight due to that reason. tri-flow should work find for it. if you would rather something else, the only other thing that comes to mind are industrial lubes such as Shell Tonna S32, Mobil DTE 24, or equivilent. if you have any buddies that work for machine shops, see if they can get ahold of some for you. a little thicker than the tri-flow, but, works just as well. i'm drawing a blank, but, another slightly thinner oil is called P38 (i believe), i can't remember who makes it. i can check it out tmw when i get to work and i'll stick up another post. it may even be a different number, but, sounds about right....

are the gears in your box plastic or metal?

good luck on the oldie and get her in the air! got any pics?

[lloydmsw]

schluterdude & tdswan,
The gears and shafts are made of steel. The crown wheel is approx 30 mm and the input bevel gear is approx 10 mm. The support bearing is in a sub-compartment of the gearbox, so I assume that gets the oil (3-in- 1 OK? I do have Tri-Flow & like it).

Never flown. Was partially built by another person. I will strip, clean, inspect, rebuild, and replace any parts that are suspect. The nuts are Ny-lock, will most likely replace the Philip-head screws with Allens.

No pics yet. I should get some soon, but I'm in the middle of re-aligning my HBCP2 and initial setup of a new Blade CP+. The Morley project will be long-term one Thanks for reminding me that I should keep a visual journal of the process.

Interestingly, the tail rotor is driven by a stiff wire directly coupled to the input shaft.

[schluterdude]

3-in-1 is just a hair on the thin side. really meant just for squeeky hinges. i'd stick with the tri-flow. but, if it says use grease first, use that. just the oil itself won't have the lubricity or "clingyness" you need to lube a gear box like that.

i use molybdemum boat grease from autoparts stores. works great, stays "wet" well, and a big tub of it isn't more than 10 or 15 bucks. it'll last a lifetime!

my schluter as well uses a wire driven tail. they were "ok" for the era, but were prone to their own unique problems. you can replace them with carbon arrow shafts, if you want to change it, that's the way to go...

[lloydmsw]

Great - THX.

I like the idea of using carbon arrow shafts as a replacement for the wire drive. :D

THX again.

[ticedoff8]

schluterdude & tdswan,
The gears and shafts are made of steel. The crown wheel is approx 30 mm and the input bevel gear is approx 10 mm. The support bearing is in a sub-compartment of the gearbox, so I assume that gets the oil (3-in- 1 OK? I do have Tri-Flow & like it).

Never flown. Was partially built by another person. I will strip, clean, inspect, rebuild, and replace any parts that are suspect. The nuts are Ny-lock, will most likely replace the Philip-head screws with Allens.

No pics yet. I should get some soon, but I'm in the middle of re-aligning my HBCP2 and initial setup of a new Blade CP+. The Morley project will be long-term one Thanks for reminding me that I should keep a visual journal of the process.

Interestingly, the tail rotor is driven by a stiff wire directly coupled to the input shaft.
Ace Hardware sells a bottle of "Turbine Oil". It is from Norvey, Inc. It is a really nice application bottle. "Highest Quality Finest, All-Purpose TURBINE Lubricating Oil" - since I don't have a turbine, I use it on my heli.

It is thicker than Tri-Flo or 3-in-1 oil, but seems to have a "slicker" feel to it. I don't use this on my drive wires - it adds WAY too much drag - but I do use it on my rotor heads and tail rotor gear boxes. Its a great general purpose oil and doesn't fly off of rotating parts.

I use Tri-Flo on my drive wires - there seems to be less drag than the turbine oil. I think it has to do with all the surface area between the drive wire and the tube.

I use the molybdenum grease to repack the main shaft bearings and the tail rotor gearbox once and awhile. Then I use the turbine oil to "freshen up" between repackings.

I use "Marvel Mystery Oil" for my engines - since you are headed to an electric conversion, you wont need this. But I buy the quart bottle of MMO at the Kragen Auto Parts and transfer into smaller bottles as needed. I use it as am assembly oil for my motors and an after run oil between flight sessions.

If you are interested in converting your drive wire to a torque tube - check out Century Helicopters. Their NX heli uses a nice torque tube and they sell the "dog bone" couplers, torque tube material and the support bearings separately. Of course, you must have a tailboom that is similar in diameter to the tailboom on the NX (20mm), but if yours is close to that, then you should be able to adapt the bearing supports.

After having my drive wire break in flight, I've thought about various replacements. My GMP Cobra uses a 1/16" dia drive wire running inside of a brass tube. I think a torque tube would be much better than a 1/16" drive wire - but much heavier. I've also been told the easiest upgrade is to use a 2mm drive wire instead of the 1/16". I've also thought about converting to a belt - but that is a pretty major conversion.

[lloydmsw]

Thanks ticedoff8,
Sounds like good advise. I believe my tailboom is about 25mm X 525mm; drive wire is 1.5mm dia.

What do you think of schluterdude's suggestion of using carbon arrow shafts? It sounds plausible & cheaper. :)