CG Ultimate 2-stoke advice
 

I'm would like to put a 2-stoke on a CG Ultimate. So far I'm looking at an OS or GMS.

Any suggestions on a good size? Is the GMS 120 too big?
http://www.mecoa.com/gms/

-Rocko

CG Ultimate 2-stoke advice
 

:) I have a Saito 120 on mine and a friend of mine has a Saito 150 on his. The Saito 120 is a perfect match for the CG ultimate.
I hope this helps.

CG Ultimate 2-stoke advice
 

I also have a Saito 120 and agree that it's a perfect match. If you have to go two stroke, I think a strong .90, 1.08 or 1.20 would do well. I have the Webra 1.20 in a Sukhoi and like it a lot. Be aware that the Ultimate cowling is not huge and that some engines may require careful planning with regards to exhaust routing.

Be careful about weight.

CG Ultimate 2-stoke advice
 

Get a 4 stroke:)!:)!:)!

Saito 1.50 would be great

CG Ultimate 2-stoke advice
 

I have an OS 1.08 in mine it flies great with tons of power. I have 3oz of weight in the tail. If I did it over I could have put mini servos in the tail and it would have been great. Be careful with anything bigger than the 1.08 or your plane will be to heavy. If I was going to buy an engine it would definitely be the 1.20 size 4-stroke.

Here is a pic of the engine install
 

cylinder side.

CG Ultimate 2-stoke advice
 

anjd the bottom.

CG Ultimate 2-stoke advice
 

I love my CG Ultimate, have been flying it for about 6 months now. Mine is powered by a YS 120 FZ, plenty of power there, but a heavy engine. AUW is just under 10lb, with nearly another lb of fuel to feed the engine.

For 2 strokes, it depends on the type of flying you want to do. OS 91 FX is a minimum, a good 108 should be aerobatic, and 120 should give you "unlimited vertical". Remember you also have a lot of drag - it is effectively 110 inches of wingspan to pull through the air.

You also need reliability, as with most bipes it doesn't glide. I know, I have a flattened undercart to prove it!

Other tips: as mentioned watch the CofG and weight of the engine. I kept one of the cut outs from the underneath of the fuz and used it to make a hatch under the pilot for the radio gear. Rudder servo is under the stab. Still needed 4oz of lead to balance.

If you can, build some right thrust into the firewall. I wish I had.

CG Ultimate 2-stoke advice
 

With my Saito installation, I moved the firewall back 3/8 inch and added 2 degree right thrust. With all the gear just aft of the wing, it balances slightly aft of nominal. 8.75 lb total weight. To install the gear at this location, I made a hatch from the fuse bottom aft of the wing and forward of the former. The receiver and battery are attached to a vertical plate that gets screwed to the former. The servos are just forward of the former.

CG Ultimate 2-stoke advice
 

I used to have a saito 120 in muy CG ultimate, then a change it for an OS 1.08 two strokes and i really feel the differnce!!, i put a cline pump and i have unlimited vertical!!

If you really want a two stroke in your Ultimate buy the OS 1.08

Just my opinion

CG Ultimate 2-stoke advice
 

I have an os 91 four stroke in mine. I have a Webra speed 1.20/cline pump in the wings waiting to install when I get bored with the OS. Problem is I am not bored yet and I find the plane truly enjoyable to fly with the 91 four stroke. I think a YS 91 supercharged would be the perfect combo.

The Webra swings a 16 X 8 Prop at 10K and I am sure will provide plenty of wobble knee excitement.

CG Ultimate 2-stoke advice
 

yes...definetely you would feel the difference with the webra 120, a friend of mine has a webra120 in his Ultimate and it flies fantastic!

CG Ultimate 2-stoke advice
 

I flew one for years (then sold it....stupid move) with a super tiger 90. I had nearly unlimited vertical and it was lighter than any other I have flown....O.S. 1.08 I would think would be great also.

P.S. don't forget the throw away the top to bttm. aileron pushrods....way too weak...I used aluminum aero-shaft (airfoil tubing) and JB welded a short 4-40 threaded rod in each end.

CG Ultimate 2-stoke advice
 

Funny you should mention those Top/Bottom wing aileron connectors. I took one look at those 2-56x12" rods and threw them away. Replaced them with CF rods. Much stronger and looks better.