25cc Eng Enough Power For 20lb Plane?
03-25-2002, 01:47 PM
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25cc Eng Enough Power For 20lb Plane?
JUST WONDERING OTHERS THOUGHTS REGARDING THIS.
I'M BUILDING A GIANT SCALE SCRATCH BUILT OWN DESIGN AND I HAVE A US ENGINES 25CC GAS ENGINE LAYING AROUND. WHEN I MOUNT THIS ON THE PLANE IT WEIGHS IN JUST UNDER 20 LBS.
IS THIS GOING TO BE ENOUGH POWER? I DONT WANT/NEED UNLIMITED VERTICAL OR ANYTHING OF THE SORT, JUST WANT SOMETHING ENOUGH TO FLY THIS THING AND NOT DRAG IT THROUGH THE AIR. MY OTHER THOUGHT WAS USING A 1.8 2 STROKE TO SAVE WEIGHT. ANY OPIONIONS APPRECIATED.
THANKS
TOM
I'M BUILDING A GIANT SCALE SCRATCH BUILT OWN DESIGN AND I HAVE A US ENGINES 25CC GAS ENGINE LAYING AROUND. WHEN I MOUNT THIS ON THE PLANE IT WEIGHS IN JUST UNDER 20 LBS.
IS THIS GOING TO BE ENOUGH POWER? I DONT WANT/NEED UNLIMITED VERTICAL OR ANYTHING OF THE SORT, JUST WANT SOMETHING ENOUGH TO FLY THIS THING AND NOT DRAG IT THROUGH THE AIR. MY OTHER THOUGHT WAS USING A 1.8 2 STROKE TO SAVE WEIGHT. ANY OPIONIONS APPRECIATED.
THANKS
TOM
03-25-2002, 10:12 PM
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25cc Eng Enough Power For 20lb Plane?
I had one on a warbird (15lbs. total weight) and it took forever to get the damn thing in the air, come to thinnk of it, it never did get in the air. I got tired of it trying to lift itself up in the air on its own so i gave it (too much) elevator and it came a few feet off the air and tipstalled real bad into the beans. Nothing broke but I dont think the U.S. 25cc will do any good on a 20lbs plane. The plane i had it on was a T-28, should have been real stable (look at the diehydral on those things)
03-26-2002, 04:13 AM
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25cc Eng Enough Power For 20lb Plane?
Rule of thumb is 0.1 cu in displacement for every pound of weight. Twenty pounds would need 2.0 cu in, or 33 cc. Not sure you'd need 40 cc, but I bet a 38 would do fine. Your 25 cc would fly a 15 pound bird.
03-26-2002, 06:36 PM
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u.s.41cc
i have a us 41 in my 27 pound 1/4 scale birddog and it has plenty of power. i also have a us 41 nib for sale . 225. 00 shipped
[email protected]
[email protected]
03-30-2002, 03:29 AM
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25cc Eng Enough Power For 20lb Plane?
You say that you're scratch building the plane. What type, I'd say the engine might work if it's like a trainer but, definately not if it's more like a CAP 232 
03-30-2002, 11:19 AM
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25cc Eng Enough Power For 20lb Plane?
how heavy of a plane can a 25cc engine pull?
Obviously the answer depends on a lot of particulars, but one rule of thumb that usually works is that 0.1 cu in displacement in a gasser will pull one pound of aircraft. 25 cc is about 1.5 cu in, which means it will pull a 15 lb plane (including the weight of the engine). This will typically allow you to do loops from a running start, but does not give unlimited vertical or hover power.
Obviously the answer depends on a lot of particulars, but one rule of thumb that usually works is that 0.1 cu in displacement in a gasser will pull one pound of aircraft. 25 cc is about 1.5 cu in, which means it will pull a 15 lb plane (including the weight of the engine). This will typically allow you to do loops from a running start, but does not give unlimited vertical or hover power.
03-30-2002, 05:19 PM
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25cc Eng Enough Power For 20lb Plane?
I would say it all depends on the style and type of plane it is. How much drag? How much lift(wing area and airfoil) all this factors in to performance. You are definetly not gonna have any vertical performance But I once had a 15 pound sig cub that flew fine with a worn out OS 90 four stroke.
