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Old Mar 26, 2012, 09:34 PM
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Originally Posted by garrettt04s View Post
What wheels are they? Size?
Du-Bro 4 or 4 1/2" bush wheels. I can't remember what the model is, but it might be balloon. I kind of think that maybe a 3 1/2" would look better.
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Old Mar 31, 2012, 10:36 AM
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Alright folks, numbers are in!!!

The 13x6 wood "electric" prop did 7380 RPM, 46 amps, and 460 watts.

The 13x4 APC prop did 9000 RPM, 32 amps, and 360 watts.

The 13x6.5 APC prop did 8400 RPM, 41 amps, and 460 watts.

What do you all think? I didn't have an assistant available, so I wasn't able to do the thrust test as mentioned earlier. The 13x4 did feel a bit stronger.
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Old Mar 31, 2012, 10:40 AM
EIEIEIO Classic is dway ta go!
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Northeast Pa. .Heyna or No?
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I guess HK makes some lousy wood props ! Did you balance it?
I'd try and fly it with the 13x4 APC.
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Old Mar 31, 2012, 10:46 AM
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I'm wondering if the turnigy light electric props are not really for electrics, I tried a 13x6 wood on my 3dhs 48" edge the other day (normally run a 14 x7 APC) and it almost smoked the motor, I didn't run numbers because I couldn't stand the way it flew, but they are nothing like the xoar wood I had before
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Old Mar 31, 2012, 11:26 AM
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Quote:
Originally Posted by pilot815 View Post
The 13x4 did feel a bit stronger.
Naturally...its like being in first gear

Any chance you have a 14x4 layin around?

Looks like the #4 pitch works good for this plane and you could stand to generate a few more watts
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Old Mar 31, 2012, 02:12 PM
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I don't have any other props laying around. This is only my third plane, and my first plane that wasn't PNP or RTF, so as you can tell, I am new to this kind of thing. I will look around and see if I can find a 14x4 just for kicks to see what it could do.
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Old Mar 31, 2012, 02:18 PM
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Originally Posted by janole View Post
I'm wondering if the turnigy light electric props are not really for electrics
I suppose not, it is noticeably heavier than the APC props. It's a shame, because it looks so good on the cub. I didn't balance the prop, but I didn't notice any vibration in the motor.

So I guess the 13x4 is lower speed, higher climb rates and the 13x6.5 is more for speed? I guess the 4 would be just fine for me. I will test fly it with both, after conducting thrust tests to see if I am close to 1:1 with it.
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Old Mar 31, 2012, 05:25 PM
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This thing is a beauty! Was watching a member fly one earlier and convinced me to finally pull the trigger. Cant wait for stock to come back!
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Old Mar 31, 2012, 05:30 PM
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Originally Posted by pilot815 View Post
So I guess the 13x4 is lower speed, higher climb rates and the 13x6.5 is more for speed? I guess the 4 would be just fine for me. I will test fly it with both, after conducting thrust tests to see if I am close to 1:1 with it.
Yea...that measurement for pitch is in "Inches per revolution" so a #4 is like first gear, tons of torque and very little speed. Trickey thing is, when you let off, just like a car, it tends to slow up VERY quickly (strong braking effect). A #6ish pitch is like 2nd gear...#8 like third...10's and 12's like 4th and overdrive. Thats why your (glow) Warbirds take a long roll to get off but have a lot of speed, They are runin prop pitch's in the "10" range.

I dont have a 14x4 Eprop or Id send it to ya...sorry.
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Old Mar 31, 2012, 05:34 PM
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I should state so you know...I dont have one of these!

If its "mushy" with the #4 pitch land immediatly and bump up to the 6 or 6.5.

Seems like I saw that someone was running a #4 pitch and it was ok but I cant remember.

9K RPM with a #4 pitch is significant forward movement.
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Old Mar 31, 2012, 06:23 PM
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Originally Posted by rcalldaylong View Post
Pilot,

as others have already pointed out, that prop is probably too much for that motor. And when a prop is too much, the motor can't turn it enough, and you get a hot motor with very little thrust.

I'd say the cheapest route would be to leave the motor/ESC/Lipo exactly where it is and simply experiment with prop size. Try 13x6 APC E, then if motor still gets hot, try 13x4. I've found 13x4 APC E to be the best for me...most efficient and still delivering the right amount of thrust I need.
Quote:
Originally Posted by Dad_Roman View Post
I should state so you know...I dont have one of these!

If its "mushy" with the #4 pitch land immediatly and bump up to the 6 or 6.5.

Seems like I saw that someone was running a #4 pitch and it was ok but I cant remember.

9K RPM with a #4 pitch is significant forward movement.
rcalldaylong is using the 13x4, but I didn't see mention of motor.
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Old Mar 31, 2012, 07:24 PM
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Quote:
Originally Posted by pilot815 View Post
rcalldaylong is using the 13x4, but I didn't see mention of motor.
The motor I have is as tiny a motor as you can get away with on this cub.
it is 118gram, and rewounded for higher KV and is now 125gram

picture here:
http://www.rcgroups.com/forums/showp...&postcount=110

Here's the motor info:
http://bungymania.com/imageshome/inc...rf1.php?id=114

My AUW is now 2180 with the extra weight coming from the reinforcement of the landing gear....and it still flies fine...plenty of power.
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Old Apr 05, 2012, 08:17 PM
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Cub flew tonight. It's still a bit slow, but at least it got in the air. I flew it on the 13x4 prop, but didn't get a chance to fly it on the 13x6. Might need some 4s power. I am on my way to work, so pictures will have to wait until tomorrow.
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Old Apr 06, 2012, 01:43 PM
Dude, I do fly all day long!
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Quote:
Originally Posted by pilot815 View Post
Cub flew tonight. It's still a bit slow, but at least it got in the air. I flew it on the 13x4 prop, but didn't get a chance to fly it on the 13x6. Might need some 4s power. I am on my way to work, so pictures will have to wait until tomorrow.
Yea, at 900kv, that 13x4, with the low pitch speed will be slow, but then again, isn't Cubs suppose to fly slow. What's nice with that 13x4 is it's slow, but gives you the needed thrust to put that big cub in the air, and also, it's a very efficient prop. If you put an amp meter on that, you'll probably notice you're probably be in the mid 30 amps or so, but definitely under 40. 13x6 would definitely give you more speed, but also at a cost of more amps, and the motor would have to be up to the task to spin the higher pitch speed, otherwise, you'd have a hot motor and no thrust.
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Old Apr 06, 2012, 02:02 PM
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Originally Posted by rcalldaylong View Post
Yea, at 900kv, that 13x4, with the low pitch speed will be slow, but then again, isn't Cubs suppose to fly slow. What's nice with that 13x4 is it's slow, but gives you the needed thrust to put that big cub in the air, and also, it's a very efficient prop. If you put an amp meter on that, you'll probably notice you're probably be in the mid 30 amps or so, but definitely under 40. 13x6 would definitely give you more speed, but also at a cost of more amps, and the motor would have to be up to the task to spin the higher pitch speed, otherwise, you'd have a hot motor and no thrust.
A few posts back, I have the info that I pulled off my watt meter. The 13x6 was in the mid 40 range. The 13x4 had thrust, but it seemed too slow in the turns.
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