OS 120 engine for a SIG 4*60
 

I have a homeless OS 120 4 stroke engine. I am thinking about putting it on a 4*60. I can manage my throttle so it does not tear up the airframe. I can also put both elevator and rudder servos near the tail to balance at the recommended CG.

One alternative is 4*120. But I am afraid that combination (120 4 stroke for a 120 size airplane) may be a little under powered.

I would appreciate your comments about putting OS120 on 4*60. Thanks in advance.

Onewing

OS 120 engine for a SIG 4*60
 

I have a TT .91 FS in mine and it's plenty of power. The TT is pretty heavy, too, so if the weight isn't much different, it should be fine. There's a lot of room to move the servos around in the fuse, so mounting them in the tail may not be necessary.

Don't expect any 3D capability from the 4*, as it wasn't designed for that stuff, but I can say it is one of the best flying planes I've ever had. And I've had a lot of them over the years. The plane is SUPER stable and landings are easier than you can imagine. It just floats and slows down and floats and slows down and...

OS 120 engine for a SIG 4*60
 

One thing I just thought about....

The TT.91 was a fairly tight fit in the nose. I don't know how much bigger the OS is, but you may want to research this a little before deciding. If you want, I can measure the engine compartment size and let you know.....

OS 120 engine for a SIG 4*60
 

I have had 4* 60s with everything from OS 91, YS 91AC and a YS 1.20 NC. With the YS 120 it flew great. But throttle management MUST be used. I got a little fast and the ailerons fluttered stripping out both servos. An OS 120 should be comparable to the YS 91AC. Just remember the throttle stick. :rolleyes:

120 is great
 

I have a 4 Star 60 with a O.S. Surpass 120 without the pump.
Great combination. I have my elevator and rudder servos mounted in the tail. I made the following modifications to my plane. I added 1 3/8 inches to the elevator and I made a Cap 232 style fin and rudder for the plane. I made the ailerons 2 inched straight across. The plane will harrier and torque roll and hover. Also it will do a real knife edge loop and a dead flat flat spin. This was the best flying plane I had ever flown until last Saturday. I flew a UCAN DO 3D with a Saito 100 and a 16-4 APC prop. This is the plane. Period..
Also if you build a 4 Star use 4-40 wire on all control surfaces.

OS 120 engine for a SIG 4*60
 

I switched from a YS91Ac to a TT 61 2S and I think I would have been happier sticking with the YS91. Just needed to slow it down a bit on the ground landing. :) I took 3 feet to leave the ground and went straight up from there, if you wanted.