I wanting to purchase my first 4 cycle engine for my Big Stik which is for 60 size, 2 cycle engines. I'm new to RC started last year been flying without an instructor for about two months. I'm looking for an easy to run, easy to maintain engine. I would like to know you opinion on the O.S FX-70 II Surpass and the O.S. FS-91 II Surpass. Weight difference is 2.35 oz. Give me both pros and cons. If you have any views on the Saito 72 pass them along.

You can't go wrong with either the OSs. The Saito is a loverly engine, but does take a bit more work to run in, so may not be perfect as a first 4 stroke if you don't have anyone else around to assist (though plenty of threads on RCU covering them).

As for size, as it is a 60 size plane, you would probably be disappointed going for either the 70s in the long run. I would suggest sticking to the 90 size engines so you have enough power to help you progress.

Don't forget the TT 91 also. Haven't had one myself, but not heard any bad comments about them other than they are heavier than the others. (but cheaper).

"Disappointed in the long run" with the .70FS?

Get out....


I've owned .70's for 15 years and am eagerly awaiting my first disappointment. It's not happened in all this time, but I feel better now that I know my first class ticket to "Sad City" is in the mail.

The .70 is a fabulous engine. Easy to run, and maintain.

More than enough power with a 13-7 for the Big Stick using 10% nitro fuel.

If all you want to do is "go vertical"....then buy an estes rocket.

'Race

A 60 sized plane ( 2 cycle 2) with a 70 4 stroker may be "scale" but it is always nice to have extra power, especially for sticky situations that arise..

If the weight penalty was small, and price was not a big factor I would step up to a 90- (need prop clearance though-)

Don't think you would have a ton of vertical with an OS-91, bit it'd be about right-

For V E R T I C A L throw a YS-120 on it>

Best of luck!

....I've used the Saito's, the OS .90, and the Magnum
.91.....the Magnum is the most user friendly, easiest
to tune, and reliable running of the the lot....

....the OS comes in second....

Dave.

The Saito .72 is every bit as user friendly as the others only lighter, actually reading the instructions makes setting up a Saito a snap. As with all other engines.