I recently aquired an ACE ultimate bipe that reqires a 15-25 size engine however it has a .35 os engine on it, it has never been flown and was scetchy on flyin it without the right size motor, will it really mater? also I was going to try to get another plane to use that motor in and was wondering if i can use that 35 in place of a 40. it seems everything i like is a 40 size , will it fly right with a 35 instead of a 40? I aint really concerned with speed so much as making go fast enough. so can i use the 35 in place of a 15-20? what abot 40?

You'll be fine. A lot of people go outside the recommended engine sizes, me included read .91 four stroke in .46 plane.
the 35 will also fly the 40 plane. You may find that after a while you get bored and want MORE POWER
Go fly your bipe, youll love the extra power.

thanx a ton, mike

The only thing I would add is if this is an older OS .35 it's probably lower in power and higher in weight than more recent engines in this size range. For the Ace bipe this will translate into a heavier wing loading. You may be able to fly it, but the higher takeoff and landing speeds might make it not so fun. Weigh the plane to see if it's within the intended range. If yes, go for it. If it's too heavy, procede carefully.

As far as using the .35 on a .40 plane, if you are looking for speed you will not be happy. Many of the current ".40" size planes are really happiest with an engine in the .45 or larger size. You will probably do better to use the .35 in a .25 size planes that specifies something like a .25-.36 engine range. These will be smaller and lighter and the .35 will give you some speed. For example, I've got a World Models Aircombat zero. It flies smooth and I haven't seen any bad habits yet. I've flown it with a Saito .45, OS .25 FSR, and OS .32 FSR. All of these worked well.

You also might want to check that the fuel tank is large enough for a 10 minute flight with the 35 engine. [8D]

It depends more on your flying style combined with the airplane. Personally I don't go for speed but on some planes I do like vertical. On scale models I usually don't over power but some scale planes need weight in the front so I would choose a heavy motor. With a long nose moment I would pick the lightest motor even if its a little less powerful. I am planning to build a Zlin and think the Saito 100 would be perfect because of light weight. Currently I'm building a Mitsubishi Claude and it has a very short nose so I will make a dummy radial to surround the Saito 180. This might add a pound to the front which will be needed. I'm not interested in over powering these models. I want to get a DPM Ultimate and plan to but a Webra 120 in it which should get the plane going very well.

You can over power models but if you use the throttle and stay close to the recommends you will be fine. Spend some time thinking about how you fly and want you want the plane to do. Put-put all the way to 3D.

Carl

I was given the ace ultimale bipe yesterday as a gift, however the plane is out of my skill level, I would just be more comfortable flying a trainer before I go straight to an acrobatic bipe, the engine is a 1988 O.S. .35 fp. the funny thing...... Neither have been ever used, or even started, but i wanted to use the motor in a trainer like a " avistar type size" plane to get used to gas first, then build up. I have flown gas but never owned gas planes, Also what would yall recomend for a trainer that will use this engine and fly decent? BTW, I WILKL BE USING A JAG RC NITROUS KIT, since I dont fly at ama sites or am I ama, Or will I be, atleast yet, And I will NOT UNDER ANY CIRCUMSTANCES BE FLYING ANYWHERE NEAR PEOPLE OR HOUSES OR CARS. " AT LEAST 5 MILES", but anyway, some trainer os easy sportplanes this engine will work well enough to train me in would be appreciated. mike