Jetdesign

My Feedback: (8)

I am not home to measure, but I used the Airtronics 94772 in the ailerons with zero modification or sanding. They are a pretty nice servo, very fast with excellent centering.

Jetdesign

My Feedback: (8)

13/16 x 1 5/8" opening for servo body, not including mounting surface.

Jetdesign

My Feedback: (8)

pics

okypolice

Guys...finally im decide to use Hacker A50-16L,cos hard to find scorpion here.But guys,i have a few question...
1.I will be use 10s with this motor,so what size of propeller do i have to use?.
2.If any body in this tread who already use this setup(Hacker A50-16L with 10s),please share with me.
Thank you guys,and i'm waiting for your reply.
Best regards,
-Oky-

tIANci

Oky ... motorcalc says a 16x10 I believe.

gaRCfield ... FINALLY!!! Let's get her up ...

hezik

Just try.. I would try a 16x12 and 17x10. Watch the engine temp.

Basically you can enlarge the prop untill you reach the point that the motor gets too hot.

tIANci

Watch out for smoke too ... heheheeheheee

okypolice

Thank you Tianci...but,in the manual said...with 8s..the prop is 18x10-12...
so,if i using 10s,is it ok if im using 16x10 as you said?..tolong lah...
and wat kinda smoke???????.....hehehe...short circuit????....

okypolice

thank you for you too Hezik....but in the manual said...with 8s,prop is 18x10-12....so..?????....

hezik

so, what?

18x12 is too big on 8s. It'll swing 18x10 tho, at 8s.

On 10s, 16x12 should be ok.

okypolice

ok hezik,thank you again..hehehe...i'll try 16x10-12.
or,do you have a website addres that i can find the motorcalc?..

Jetdesign

My Feedback: (8)

So you are limited to the amount of current (amperage) you can run through your motor (and ESC). 8S (roughly 30 volts) and a 18x10 (whatever resistance) will produce somewhere around 65-70 amps. You are increasing the voltage, so you must reduce the load to produce the same amperage.

Don't forget to consider what weight you want the plane to fly at. If you've read through the thread, you know there is an issue with down line acceleration. Presumably it is increased with heavier weight. My plane came out to 4.3kg, and (sorry for conversion factors) my motor is 2oz lighter and my gear is 40-50g lighter. Also a 16" prop will provide less breaking.

All that being said, I continue to watch videos of the plane and immediately can notice the very light wing loading with the lighter setups, which to me looks too light for pattern.

Jetdesign

My Feedback: (8)

[link=http://www.castlecreations.com/support/flight_calculator.html#]Castle Creations Calc[/link]

okypolice

thank you very much for the explanation joe....i understand now,that...if i go with 10s,i should reduce the load to have same amperage with 8s..(something around 65-70 amps)..but joe ,if im using higher voltage speed control(im using hobbywing 120hv),does it still have a problem with the amperage??..sorry im very newbie in electric.

hezik

This is not the correct reasoning.

Your engine has a certain kV, a theoretical RPM it would run on 1 volt. So increasing the voltage, increases the RPM.

So your engine will run at a higher RPM. THAT's why you'll need a smaller prop to keep the load the same.

okypolice

so hezik...if im not reduce my prop..what are will be happen?..
1.is it the amperage will be higher than the usual result?
2.or the motor will be damage?.

Jetdesign

My Feedback: (8)

I'm pretty sure you just said the same thing. You need to reduce the prop size to reduce the load.

If you don't reduce the prop, the load will cause the system to draw more current (amperage) and yes, you can damage the motor. The motor is specified to run at a certain amperage. You need to prop your system to stay within this range.

hezik

No your cause and effect was wrong. You said that because of the higher voltage, the current would go up. That's not true. The current increases because of the higher RPM. Admittingly it's nitpicking, but there _is_ a difference, which one has to understand to understand how electro setups work.

At Okypolice: if you don't reduce the prop size, you would be asking more from your engine than it could deliver. It would run hot, too hot, and eventually the magnets will demagnetise and your engine will fail. Or your ESC will burn out.

RCBruski65

My Feedback: (44)

The motor is going to try to turn the rpms that it should for a 10s pack. It doesn't care about amps it is trying to turn the rpms. Too big a prop the motor will draw too many amps and could damage itself as well as the speed controller.

okypolice

thank you very much guys(hezik,joe,rcbruski65)....its very clear now....im really appreciated....so i'll start with with 16x10e,and see how is the result..will be inform to you guys..
Best regards.
-Oky-

okypolice

Sorry guys,..one silly question from newbie....
What do i get from this setup(Hacker A50-16L with 10s,and 16x10-12e in prop)?
1.More power and less amperage?
2.More power and more amperage?

Jetdesign

My Feedback: (8)

I see what you guys are saying. I was looking at the system from an outside aspect, mainly from the motocalc numbers - take a setup and increase the voltage, the amperage increases with it. I understand it is a function of the motor workings and not directly a function of the charge.

Oky, generally if you increase the voltage but maintain the same amperage, you are increasing power, which is what you are shooting for. You have to play with the numbers in a motor calculator though, as things like prop and motor efficiency will have an affect. I believe there is two aspects of power - power into the motor and power out of the motor.

Let us know how it works out. I emailed Hacker about running that motor on 10S - they said it would work but they didn't recommend it.

hezik

Probably around the same power at a lower current (amperage).

Jetdesign

My Feedback: (8)

I thought you said the idea was for him to reduce the prop load so he would maintain the same amperage that others are drawing on 8S.

If he was making the same power at less amperage, then theoretically he could increase the amperage for more power.

hezik

He might just. Overall if you use more cells (volts) you can increase the maximum output of a setup (more Watts), but not endlessly.

The engine has a resistance and this is partly responsible for the heat buildup. By using a higher voltage one relatively lowers the power dissipated by the resistance (=heat) and increases engine efficiency.

So yes, he might get more power, but he has to swing a smaller prop at a higher RPM. It's always a compromise.