I have two unbuilt planes in my hangar, an ultra stik 60 with a saito 91 and an ultra stik 40 without and engine. I want to build the ultra stik 40 first and have not decided what engine that I want to run in the 40. I want a 4 stroke and am looking at the OS surpass 70, the saito 72 and the saito 65. Since the plane that I plan on having for a long time is the ultra stik 60 I just want a good running easy to build and balance 40 size plane. I do not want to have to worry about cutting holes to mount the battery as well as relocating the servos to the rear of the fuselage. Any suggestions as to which engine to go with? How would a Saito 56 or OS 52 4 stroke run this plane? I would like to start to learn how to hover with the 40 so I will be very comfortable with the 60 when it is time to fly it. My current plane is a Worlds Models Super Sport 40 low wing trainer with a GMS .47 engine.

Chris

The Saito 72 will fit right into the aluminium engine mount. I'm not sure it will hover though.

I have an OS 50 max in mine. This is a great preforming engine. I am turning a 12 1/4 x 3.75 prop on it. It has very good vertical preformace. A buddy of mine is putting one together with the same combo. Hope this helps
Later
Nate

I had a Saito .72 on mine (later swapped out for a YS .63). Made all the basic mods, like pinning the firewall with toothpicks and reinforcing the landing gear plate.

All servos were placed in the standard locations. HS-422 on throttle, HS-615MGs on rudder & elevator, MPX Profis on flaps and ailerons.

I had to place the 1400 mAh 4-cell nicad rx battery pack in the tail in order to balance the plane. I cut an access hole in the top sheeting about 3/4" behind the wing, velcroed the pack in place, and covered the hole with tape. Once the plane was balanced to my liking I CA'ed a balsa stick in place to securely trap the battery and covered the hole with white Ultracote.

It flew quite well, and did everything I asked of it.

I gave it away to one of my flying mates a couple of months back. His radio doesn't support a 4-servo wing, so he cut off the flap and aileron surfaces and put the standard ailerons on. He's flying it now with a Tigershark .53 2-stroke. He's balanced it in the same way I did - using a 4-cell 700 mAh nicad. (his engine weighs less than mine did.) He's having a blast with it.

Nate:

I saw one of those sx 50 at my hobby shop and it caught my attention. How does its power compare to a saito 72 in hovering for example? It looks like the os was made for this type of plane.

Chris

I have a OS 46FX with a MAC's tuned muffler and it balanced well w/o any additional modifications. I did make the recommended modifications as was mentioned earlier but this engine will perform real well with this plane.

with the os .46 did you use the stock aluminum mount or a plastic one? There is a 1 ounce difference between the 2.

chris

A guy at my field has an O.S. 91FS on his and he does some crazy stuff with it. Makes it really fast too. I have the .70FS on mine, but I am jealous of his. I would go with the .91 four stroke