ORIGINAL: rcdude7
I have searched and not found much on these engines. I have become the owner of one in excellent condition and would like some care and feeding tips from the experts out there, please. This engine has a iron piston, steel sleeve and baffled piston crossflow porting. I am sure that fuel with lots of castor is needed, but what % nitro is good? 5 or 10% maybe? Also, what is a good APC prop and RPM range for this engine? I may run this engine in a small cub or trainer type plane for some old school fun. Not trying to suggest any of you are OLD as I am turning 40 this month and feeling it slowly but surely
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Thanks in advance for your advice.
Mike
Mike, I also have 2 of these engines (plus many other OS engines as well) - Jim is absolutely correct - the OS Max "S" series are simply wonderful engines, being reliable, very economical & powerful for their design & age.
The fuel MUST be min. 25% Castor oil........no if's or but's........these engines were designed & manufactured in the pre-synthetic oil era & MUST be run on castor if you want the engine to last any longer than 30 minutes. It's not negotiable! Do the right thing & the engine will last many years. In fact only yesterday my son & I were flying his trainer aircraft - it is powered by an OS Max "H" 40 (twin ball races & ringed). Runs surperbly on the 25% castor mix.
I find something very appealing about using engines of another era.....maybe it's the smell of the castor, the novelty factor. And the fun thing is that the other guys at the field often wonder what type of engine I'll be bringing with me today. I enjoy it.
I am now looking at the OS Max 30 S instruction leaflet. There is some generalized recommendations about prop sizes but of course it all depends upon the model etc. OS suggest 9 x 5, 10 x 4. The leaflet recommends 5% nitro for contest use.
If you like, you can PM me with your postal address & I will send to you a photocopy of the leaflet. Either that or I will post a scanned copy onto this thread - your choice.
Greg aka BONE
Reason for edit: spelling error or two