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Old Dec 14, 2010, 03:00 PM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
Help!
RC Scratchbuilt from Harbor Freight Piper

I've been working on a scratch built trainer plane using parts from a harbor freight piper cub http://www.harborfreight.com/remote-...ane-92906.html, but it wont get enough power to fly, I'm using a larger prop than recommended, could that be the problem? I also accidentally charged the battery overnight without realizing that the charger didn't have a cutoff, could that have ruined the battery?

Specs

Weight~12.1 oz
Span~39"
Chord~4"
Nose to base of tail~20"
Wing mounted 5" from nose
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Old Dec 14, 2010, 03:13 PM
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, AK, Fairbanks
Joined Aug 2009
12,397 Posts
The site has too little info on the plane to tell, but it looks like a brushed motor. If it is, there's no way it's gonna spin that big of a prop fast enough to get it flying.

Also, you run a high risk of frying your ESC and motor.

Prop down, or better yet get a brushless/lipo setup. The plane itself looks good, though....
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Old Dec 14, 2010, 04:51 PM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
would it work to try trimming the prop to size?
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Old Dec 14, 2010, 05:00 PM
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, AK, Fairbanks
Joined Aug 2009
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Not really, because you'd have to chop off about 2/3 of the material and you'd probably have to make the chord smaller as well. THe prop will be less efficient, and there's balancing to think about as well.

It'd be better to just buy a smaller prop, around the size of the one that came on the Cub....
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Old Dec 14, 2010, 05:32 PM
Fueled by Arabica Beans
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United States, NY, Syracuse
Joined Oct 2008
3,895 Posts
The prop is on backwards as well, but it doesn't matter... as others have said it's too big. The convex side of the prop should face forward and the concave part should face backward. Also, you can't glue the prop on and expect it to stay attached. You need to find a hub that will properly attach it to the motor.
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Old Dec 14, 2010, 08:01 PM
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, AK, Fairbanks
Joined Aug 2009
12,397 Posts
Oh, jeez, I didn't even notce that. I just glanced at the thumbnail in the post; upon closer inspection I must concur that the prop is on backwards.

It looks like you shoved the prop onto a pinion gear on the motor, then glued it. Correct? Is that the prop that came on the Cub?
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Old Dec 14, 2010, 09:33 PM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
Quote:
Originally Posted by TP16 View Post
It looks like you shoved the prop onto a pinion gear on the motor, then glued it. Correct? Is that the prop that came on the Cub?
I used heat shrink tubing to enlarge the shaft size to where it would fit, then glued the prop on. Is it bad to have the prop on backwards?

Would the battery be bad because of overcharging it?
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Old Dec 14, 2010, 10:15 PM
Fueled by Arabica Beans
ChillPhatCat's Avatar
United States, NY, Syracuse
Joined Oct 2008
3,895 Posts
The battery is probably fine. You need to get the prop off and attach the correct sized prop to it and not backwards. They are highly inefficient in that configuration. What happened to the plane that it came from and the propeller/hub that it had? You just cannot attach a prop to the motor like you did, it will not hold up.
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Old Dec 15, 2010, 11:14 AM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
Quote:
Originally Posted by ChillPhatCat View Post
The battery is probably fine. You need to get the prop off and attach the correct sized prop to it and not backwards. They are highly inefficient in that configuration. What happened to the plane that it came from and the propeller/hub that it had? You just cannot attach a prop to the motor like you did, it will not hold up.
The plane had been in a crash, and had a broken prop. i ordered the correct size prop earlier today, hopefully will come Saturday!
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Old Dec 15, 2010, 07:41 PM
Registered User
United States, NJ, Frenchtown
Joined Mar 2003
9,075 Posts
Well you are learning.

The Battery needs about 5 flights to really get strong.
The plane can barely fly in some wind.
Both Cubs I put together needed a different COG.

The props break VERY easy. Or almost break in any grass landing.


THI IS NOT A BEGINNERS FIRST PLANE........A club field is the right place to have it checked out & maybe flown by a good pilot to see if it is ready.
The wall charger WILL overcharge the battery. Feel the battery every 1/4 of a hour. When you feel a little warming, Take it off of charging.
You DO NEED to charge it a couple of hours before a flight.
The battery likes to move around sometimes......use double sided tape or Velcro.
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Last edited by cyclops2; Dec 15, 2010 at 07:47 PM.
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Old Dec 16, 2010, 08:03 AM
Registered User
United States, NJ, Frenchtown
Joined Mar 2003
9,075 Posts
96

I have done many different modifications to them. ALL COST MORE THAN parts or another BETTER.. FIRST BEGINNER plane would cost.

I can afford to spend a LOT more money, than I will save.

I suggest you post what you have in parts, what you can spend right now, & what should you do or save up for..... Post in the Beginners section.
You will see the good & bad planes on any budget you may have.

Flying alone is VERY expensive & frustrating. Try to connect with a local ??? AMA flying club. They ARE WHAT YOU REALLY NEED at this time.
below is the website for the AMA. They have hundreds of clubs around the country. type in your ZIP CODE there.
Post back if you have trouble with the website.

Rich

www.flyingmodels.org
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