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.46 Engine Prop combo for best torque?

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.46 Engine Prop combo for best torque?

Old 09-21-2011, 08:17 PM
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timcat26
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Default .46 Engine Prop combo for best torque?

Evening all,

I'm looking at putting together a plane to fly in our Club's Heavy Lift contest. So far, I'm leaning toward using a NexStar with a .46 (most engine allowed for Nitro class). Engine and muffler must be stock. I'm interested in opinions on which engine and prop combo would give me the most torque. I have a Tower .46 that I've heard provides a decent amount of pull, and if I go with it I'm looking at using an 11x4 prop, possibly a wide version. Any other thoughts anyone would care to share? O.S.? Magnum? Thunder Tiger?

I would appreciate any input. Thanks!


Old 09-21-2011, 08:54 PM
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proptop
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Default RE: .46 Engine Prop combo for best torque?

You might also try an APC 12.25 x 3.75
Old 09-22-2011, 12:33 AM
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jaka
 
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Default RE: .46 Engine Prop combo for best torque?

Hi!
11x4 is too small if you fly at sea level.
Either a 12x4 RAM, Graupner Cam-prop or APC or a 12,25x3,75 APC propeller.
As for engines the Kyosho GX.40 or .46 is the best sport engine today together with TT SE .40 or .46 (The Kyosho GX engies are the same as a ASP.40-.46 but with bigger exhaust opening in the silencer).
Old 09-22-2011, 03:04 AM
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Default RE: .46 Engine Prop combo for best torque?

'The most torque?' The engine supplies a fixed maximum amount of torque at a certain RPM. You can find this RPM by checking the engine performance graphs, providing the engine has been tested. Prop the engine to run at this RPM. That will be max torque. It might not give you the best performance for what you are trying to do. If you need horsepower, then you must prop the engine to give you the RPM where the most HP is released, again, available from the engine graphs. The torque peak and HP peaks will not coincide, the max torque may well be delivered at quite low RPM, and max HP at quite high, and unuseable, RPM. To do what you are trying to do you must match power and pitch to provide the best performance at the speed you expect the model to fly. This can only be done by experiment as the ground 'static thrust' is only a measure of how good a fan the prop is, and will bear little relationship to the thrust developed in flight. No easy answers.
Evan, WB #12.
Old 09-22-2011, 06:48 AM
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jester_s1
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Default RE: .46 Engine Prop combo for best torque?

To maximize static thrust, it's all about diameter. If you're in the mood to experiment, buy props from 11 to 13 inch from 2 or 3 manufacturers in the lowest pitch. Then hook up a fish scale and see which one pulls the hardest. That said, if you're talking about loading the plane with weight and seeing who can fly the heaviest plane, you need a prop that will fly the plane at it's lift/drag max with the weight on. That will likely not be the prop that pulls the hardest, but that provides decent speed and enough pull to accelerate the weight down the runway.
Old 09-22-2011, 07:43 AM
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R8893
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Default RE: .46 Engine Prop combo for best torque?

Several years ago we were doing control line racing of scale Golden Age race planes. .40 engines and 11" props required. The Thunder Tiger 40 was he best (at a reasonable price) turning this "large" diameter prop.

I spent three years with local university students on their heavy lift projects and totally agree with Evan (Pimmnz) on torque vs horsepower. Horsepower is what gets the job done.

Unless you can use a reduction drive, you'll just have to experiment with the large diameter, low pitch props.

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