O.S. 40H

Little Don : Can anyone tell me about this engine. This one has only one main bearing and two rings. Is it as good as a S.T.46?Don

Hmmmm,
All the ones I've ever seen had TWO ball bearings. Not bad stunt engines, but a little heavy for the power delivery. I think Les Mcdonald, Stan Powell, and others used them pretty successfully during the 70's. At least that's my recollection...
"Dankar" has severl now, I think.

The version with two rings and one rear bearing is totally different than the single ring version with two bearings. The single ring version is the later version, it has a larger bore and shorter stroke than the dual ring version. Hardly any parts will interchange.

Kiwi is quite a fan of the 40H, he didn't say which version. OS also made a 40H that is for pylon racing and it is totally useless for stunt.

The 40H will 2-4-2 and is a useful stunt motor.

I have several .40H with single ring dual BB. They run fine and are user friendly. Like Randy stated a little heavy but not bad. Average power for a .40. This is not a ST .46 by any means. The .40H-P was a pylon/ rat race engine and was made to go fast. The double ring single bearing I have no idea. I like the 4-2 break and ST and OS's are my engines of choice. I like Johnson's and Veco's too. Cheers,Dan

>Little Don : Can anyone tell me about this engine. This one
>has only one main bearing and two rings. Is it as good as a
>S.T.46?Don

With a Clarence Bull BY-O 11-5 prop, 10% nitro, 25% lube (11% synthetic, remainder castor), I always thought this an excellant engine for the Oriental. It had a little more grunt than the OS Max-S 35, and gave my Oriental the power it needed to get it out of the trouble I put it in.

The only fly in the ointment with this engine is you have to deal with rings - and rings will wear and fail after a while. The good news is that you can have Frank Bowman make new ones that work great. I wouldn't run all castor in it as that eventually gums up rings and you won't get a good seal. At the same time, don't go all synthetic, either. A blend of both has kept my Max-H 40s running well. Replacement bearings are pricey, but work well and this engine does not like to wear out if you use a good fuel with adequate lube.

Best of luck with yours.

V/r

The OS 40H with 2 ball bearings came later. First was the single bb rear bearing with the plain front bearing.... Most common versions were the 35"H" a combat/rat motor and the 40"s" a stunt motor.

The 40S is an excellent stunt motor and the 40H is almost as good.
I have two 40S and three 40H motors(plus an old H40P plyon motor that I used in Navy Carrier).
One 40S is in an old Coyote an the other is in a Doodle Bug. Both run with Sullivan 6oz clunk tanks on UniFlow, and 2-4-2 very very well. No muffler pressure (sometimes no muffler at all)on the Doodle Bug and muffler presure used on the Coyote.
All my OS 40 motors are in models.
Believe anything you want...... but if you want to sell the 40S or trade it for a 40H, drop me a note!

Just for yucks..... the photo is an old Mathis "Jaguar" with a 40H.
Usually run slobbering rich with a massive but almost pitchless prop.
Great model for the "Straight & Level NATS" or the large version Walker/BlackHawk contest..... or an easy flier with lotsa pull for new folks to get a feel of the handle.

Vince

Little Don : Vince do the 40S have one main bearing and rings? I have a 40h with one ring and one with two rings and they have one main bear. I also have two new 40h with two bearings. Iwould like to have a 40s. Would you trade for a new 40h that has two bearings? Don