SCORPIO_2727

Opinions please. Convering another glo to diesel. Have a near new OS 61 FSR glo; also an OS 1.9 to 1 reduction gearbox that bolts on in place of the crankshaft and front housing. The reduction gearbox crankshaft connects to the conrod. The carby is relocated in this housing. As a glo, this combo will swing an 18X6 prop, but with the exhaust bark of a glo and the gearbox(metal gears) sounding like an airborne sewing machine, the sound is out of this world. How would the 61 fare with a diesel head fitted? Should cut the exhaust, but running the diesel thru a reduction gearbox is new to me. Guess I will have to live with the sound of an airborne sewing machine gone mad. I'll reduce the size of the carby throat. But a diesel thru a gearbox? Is it worth a try? Glen

Ldalmas

I think it is a bit to far fetched you will have to turn a 22¨ prop to sadisfy it.

AMB

scorpio Would you post a pix of this I (and sure most have never seen one)seems it might fly an almost 1/3 scale WW! bird with that
combo There is no reason why it will not work the crankpin could care less what makes it go up down and around sounds like a great
idea to swing a very big prop martin

NM2K

My Feedback: (14)

I sold my OS .61 VF (same as FSR, but rear exhaust) to a friend. He bought the OS reduction unit and mounted the whole thing on a built upside down Super Kaos 60.

His was operating on glow and running a tuned pipe. The sound of the gearbox drowned out everything else. Neat.

SCORPIO_2727

Martin, no problem. I knew I'd receive a positive response from you. Yep, my eyesight and reflexes aren't as good as they used to be. Models small or fast models now not for me. Big, gentle and sedate (more like me) now more in my line now. The OS 61 with the reduction gear will be going in a large Buker bipe. Had an OS 80 2 stroke glo, but marginal power for it's size. . With the reduction box on the 61, I won't have to use full power all the time. Also a very large prop will protrude out further than that big cowl== more efficient. I could use up to a 22inch prop with the diesel conversion; have plenty of ground clearance. I was hoping someone out there could also suggest a whiz-bang suggestion to cut down the noise of the gearbox. Glen




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SGC

Glen,
Is the G/box lubed by the fuel , or is it sealed and prelubed ? If pre lubed you could try putting in some Nulon G70, this is a teflon additive for gearbox/differentials. I have used this and it works, it reduces noise, friction( have used it in an industrial power takeoff box that ran so hot it hardened the seals, after adding G70 it got no hotter than the motor bellhouseing it was mounted to), its great stuff and an aussie product.
Stewart

AMB

Th could very well be the ultimate diesel, Just a guess 2 to 1 reduction ?. all that torque as a diesel than times two, again if the engine runs at say 8000 prop speed 4000 with that BIG prop getting close to full scale rpm well maybe a little quicker since I think full size may spin about 1800 hmm an RCV 4 strk diesel?? interesting thought but do not have a clue how you would adjust the ccompression
martin

Motorboy

I can see at the picture in post #5, these engines has gear ratio at 1.9:1 and 1.4:1..

Jens Eirik

SCORPIO_2727

Stewart, your query started me wondering. After having this reduction gearbox all these years (about 1 hrs use), have never had the front of the gearbox off. So, had a look. The gearbox crankshaft is sealed at the front as per the original. A small amount of clear grease had been thrown from the gears to the inner wall of the gearbox casing. If I'd kept on using the gearbox, the gears would have been running dry. Not good. The reduction shaft seats at the rear in needle rollers with a rubber seal. The grease around the needle rollers is retained by this rubber seal. The normal front bearing on the reduction shaft is sealed as per normal, front only, behind the prop boss. Looks like I give that product you mentioned a try, Stewart. I intend to pack sufficient lubricant in the gearbox so that the teeth of the small drive gear are running in the product. Phew, thanks a lot, everyone.

SGC

Glen ,
The G70 is an oil additive, it needs to be mixed with oil for use. For your application I would mix it 15parts oil to 1 part g70, also I would use auto trans oil in the g/box for low drag.
You will only need a few cc of the G70 for the OS g/box so add the remaining to your car diff, it'll run cooler quieter and give you maybe 1/2 mpg better fuel ecconomy.
ALSO NOTE, useing Teflon and molybdemon additives in too high a concentration can be detrimental, the additives can build up to the point of causeing ceasure of the parts, so never use them unmixed.- I understand the Australian Air Force experianced wheel bearing failures on some of there jets caused by useing mollybond grease additives in too high a concentration. Apparently the higher the speed the lower the concentration needed , at the other end of the scale we used high concentration moly grease on the sticks/pinnion of our coal mine face shovel- slow speed app.
Stewart

SCORPIO_2727

Thanks, Stewart, for that added info. I would have walked into that one, boots and all. Will follow yuour recommendations. The present bearings are okay, but I'll go the whole hog and replace them now the gearbox is down. (NSK bearings in there now, so won't have too much trouble getting replacements locally). Good thread with nice people. Glen Ps. Still have plenty of ether?