Help choosing a prop for my Stick

[Dr Kiwi]

Since DriveCalc was mentioned here is a plot for a Turnigy C3530-1100 (the Aerodrive version is not in there).. it suggests that 10x5 APC E loads the motor appropriately (about 70% efficiency and close to the 3W/g "rule of thumb").

Play with DriveCalc and you'll see how efficiency decreases once you get above 3W/g... you might get away with 11x5.5 or 10x7.. but that is pushing it.

Cheers, Phil

[Robio]

Originally Posted by Dr Kiwi

Since DriveCalc was mentioned here is a plot for a Turnigy C3530-1100 (the Aerodrive version is not in there).. it suggests that 10x5 APC E loads the motor appropriately (about 70% efficiency and close to the 3W/g "rule of thumb").

Play with DriveCalc and you'll see how efficiency decreases once you get above 3W/g... you might get away with 11x5.5 or 10x7.. but that is pushing it.

Cheers, Phil

Fantastic, thank you. I'm still learning the relationship of all these factors and the effects the changes make. It's a bit of a mystery to me but it's starting to make sense.

Rob.......

[kyleservicetech]

Originally Posted by Robio

Fantastic, thank you. I'm still learning the relationship of all these factors and the effects the changes make. It's a bit of a mystery to me but it's starting to make sense.

Rob.......

Yeah
Once you get above about 100 watts per ounce of motor weight, or about 3 watts per gram, you've got to really watch the motor efficiency. Some of those el-cheapo motors are claiming 150 watts or more per ounce of motor weight. These same mfg usually NEVER list the motors winding resistance, a pretty important figure for these motors.

If you run these motors at these high levels, www.motocalc.com usually suggests the motor will burn up. At any rate, their efficiency per motocalc is often under 60 % or so, a lousy number, when a quality motor is in the high 80% or even low 90% range.

[Robio]

Originally Posted by kyleservicetech

Yeah
Once you get above about 100 watts per ounce of motor weight, or about 3 watts per gram, you've got to really watch the motor efficiency. Some of those el-cheapo motors are claiming 150 watts or more per ounce of motor weight. These same mfg usually NEVER list the motors winding resistance, a pretty important figure for these motors.

If you run these motors at these high levels, www.motocalc.com usually suggests the motor will burn up. At any rate, their efficiency per motocalc is often under 60 % or so, a lousy number, when a quality motor is in the high 80% or even low 90% range.

This plane is a cheap foam/Depron slow flyer. I'm running it at just above half throttle for most of the flight. Takes only a bit more to get if off the ground!...
I'm curious though. I have a couple of higher performance planes to build. What do you like for motors?

Rob.....

[flydiver]

Originally Posted by Robio

I'm curious though. I have a couple of higher performance planes to build. What do you like for motors?
Rob.....

Too general. You're better off finding the thread about the particular plane(s) and asking there.

[kyleservicetech]

Originally Posted by Robio

This plane is a cheap foam/Depron slow flyer. I'm running it at just above half throttle for most of the flight. Takes only a bit more to get if off the ground!...
I'm curious though. I have a couple of higher performance planes to build. What do you like for motors?

Rob.....

IMHO, on these smaller "Foamies" just about any quality motor will do the job. But, I don't like to skimp on the motor when going to models over perhaps 1KW or so. As for me, all of my 1 KW plus motors have the Hacker name on them, and all of them perform very close to their specifications.

[Robio]

Originally Posted by kyleservicetech

IMHO, on these smaller "Foamies" just about any quality motor will do the job. But, I don't like to skimp on the motor when going to models over perhaps 1KW or so. As for me, all of my 1 KW plus motors have the Hacker name on them, and all of them perform very close to their specifications.

Thank you Sir,

I've heard nothing but good regarding Hacker motors.. I have an Axi motor I may use, but have'nt deceided on the build for this particular model yet. If I build it "light", I will use it.
Nothing I have requires 1kw of output, yet.. Somewhere in the neighborhood of 600w.

Thanks again, Rob....

[kyleservicetech]

Originally Posted by Robio

Thank you Sir,

I've heard nothing but good regarding Hacker motors.. I have an Axi motor I may use, but have'nt deceided on the build for this particular model yet. If I build it "light", I will use it.
Nothing I have requires 1kw of output, yet.. Somewhere in the neighborhood of 600w.

Thanks again, Rob....

Yup
IMHO, about 1/3 of your models $$$$ should be for the model itself, about 1/3 for the power system, 1/3 for the radio.

So, it makes little sense to put one of those "Orange" receivers into a model worth well north of $500. Or, put a $200 receiver into a little foamie.