formerlyknownasAWB

I am building a Spacewalker .10 and was curious how much the motor should face to the right? Does it vary by motor size?

Here is a pic of what I mean

soarrich

My Feedback: (98)

3* is the most common. I'd say that it variers more with the drag of the airframe, a very draggy airframe takes more.

Remember to mount the back of the engine off to the left side, (when viewed from the top), so that the prop drive on the crankshaft is centered in the front of the cowl.

combatpigg

My Feedback: (3)

Your question has no arbitrary answer here, just fly the plane in as straight of an up line as you can to see if it wants to pull to the left. Make sure the lateral CG is set before spending time on other tweaks, also. If you can see what the plane wants to do while in a prop hang, that can be revealing if you are flying in still air. Generally speaking. the bigger the prop diameter, the more you see the need for right thrust. 1/2A models rarely display the need for very much, running 6 inch props. When you play with models that use 14 inch props, then the need is magnified.

formerlyknownasAWB

straight lines would be nice,

Digger RCU had started to explain in the other forum the effects it would have through acceleration and at higher speeds.

I guess I was looking for the scientific answer.

combatpigg

My Feedback: (3)

If the designer of a kit has first of all built a straight plane, then found through trial and error that it flies better with X degrees of thrust, then I wouldn't want to redo his hard work. OTOH, some model designers will arbitrarily throw a tiny amount of right thrust in because they are aware of how poorly a plane will handle with left thrust accidentally built in. Has something to do with P factor and torque reaction. All I know is 1/2A engines with 6 inch props don't develope very much of either force, but larger models and real planes have handling issues if the thrust angle isn't set right. I don't think your .10 powered model will need any thrust angle turning a 7x3 prop.

John C

That's the HOB kit. Build it like the plans indicate and it will fly as good as mine, both with floats as well as conventional gear .

I used a Norvell .074 and it's plenty of power for the airframe, which wants to fly on the wing, not be hung on the prop .

John C

combatpigg

My Feedback: (3)

The proof in whether or not the thrust angle is necessary will come after the model is trimmed for hands off flight at X speed, then increase the speed. If the model begins to crab, if not roll as a result of a speed change, then the thrust angle is at fault. Either that or the model is built crooked. Once the plane has been trimmed well for hands off flight, land it and then take a good close look [with an incidence meter] at where the flying surfaces need to be set for hands off flight. If everything is zero-zero-zero, then you can't do much better than that.

BTW, "flys on the wing" translated means that the plane isn't very sporty, it flies more like a glider.

John C

The Spacewalker is 'sporty' enough . It's just not a missle like some people want . It dosen't knife edge well, lots of couple, but otherwise it's an honest airplane, with no bad habits .

John C

combatpigg

My Feedback: (3)

I hope all goes well, but the amount of thrust angle I see in that photo looks "cartoonish".

formerlyknownasAWB

thats what I'm talking about. Its how the kit comes from my understanding

we'll have to wait and see.

combatpigg

My Feedback: (3)

AWB, you can always file the backside of a plastic engine mount at an opposite angle to compensate for the firewalls' angle....if you don't like flying this plane with "vectored thrust".