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Old Apr 30, 2015, 02:33 PM
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apprentice s power 15 motor?

hi all,i just installed the eflite power 15 motor in motor in my apprentice s and on the first flight it was completely out of control.it seems like you can only fly at 1/2 throttle or it goes straight up and if you try to fly level it goes up and down out of control.we played with all the trims and got it so it was flyable but still if you give it any throttle over 1/2 it starts climbing fast.should a person put more down thrust on the motor to make up for the increase of power?any help would be great.thanks tom
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Old Apr 30, 2015, 04:06 PM
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Sounds like your CoG has now changed. You may want to make sure your plane is still balancing correctly.
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Old Apr 30, 2015, 04:50 PM
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I checked the cg and it looked good but I did a lot of repair to the and it might be tail heavy and the power 15 motor is shorter than the original motor so I spaced the motor out to where the old motor was which seems like it has better balance now.i am going to try it this weekend.thanks for the help,tom
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Old Apr 30, 2015, 06:29 PM
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Out of curiosity what prop are you using on it ?
I use the PKZ1012 on my Power 15 in low wing super cubs .
If I remember correctly it draws 28 amps and 322 watts on an Eflite 2200 3S .
The mount I use is the PKZ4428 .
Crazy fast . I have not experienced the problem you describe .
I do have a mount for the Apprentice but havent tried it yet .
It has the motor offset built in . Building a plane for it to go in .
The CG being off sounds about right .
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Old May 01, 2015, 06:57 AM
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hi,i am using a 10x5.5 apc prop,we tried a 10x7 and thought the smaller pitch would slow it down but give more thrust which seemed to help.i can get use to the speed but every time you give it more than half throttle and goes up at a good rate is going to a bit of a problem.haven't tried it yet hope to sat.
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Old May 01, 2015, 03:12 PM
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Common problem.

You probably are not using enough rubber bands to hold down the wing. It's very common with the Apprentice.

If you do not use the 10 or 12 #64 bands the wing will lift off the fuse in flight.

When this happens it changes the wing incidence. Lifting the front of the wing and making the plane go vertical.

Try adding more bands to make sure the wing is not lifting off the fuse.
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Old May 01, 2015, 04:04 PM
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hanks for the reply I use 8 rubber bands and never had that problem till I put the eflite power 15 motor on it.maybe because of the extra power the power 15 puts out it may need more bands.i will give that a try and see what happens.thanks,tom
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Old May 01, 2015, 05:06 PM
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The e-flite power 15 motor is a straight swap. The plane flies perfectly with it. Does not effect CG to any significant degree. Does not overpower the plane or cause any issues whatsoever.
Do not deviate from the standard thrust line. Do not space the motor out.

Sounds like the tail repair might be to blame. Either tail heavy or slop to elevator linkage? The up and down movement (oscillation) sounds like free play in elevator linkage or servo (maybe broken servo teeth?).

Some other items to consider if upgrading motor:

http://www.rcgroups.com/forums/showt...1#post28800830

http://www.rcgroups.com/forums/showt...5#post28837710
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Old May 01, 2015, 07:23 PM
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I had the Apprentice. If you can pull the wing off the fuse by hand you either do not have enough bands or the band's your using are worn out.
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Old May 01, 2015, 08:30 PM
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I had to replace the elevator servo so it is brand new the linkage looks good.this is the second time I have repaired the fuselage so I think that maybe with the glue I used it is making it tail heavy,the break is at the smallest part of the fuselage.i think it might just be time I bought a new fuselage,hopefully that will work.thanks,tom
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Old May 02, 2015, 08:17 AM
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Quote:
Originally Posted by tfbowen View Post
I had to replace the elevator servo so it is brand new the linkage looks good.this is the second time I have repaired the fuselage so I think that maybe with the glue I used it is making it tail heavy,the break is at the smallest part of the fuselage.i think it might just be time I bought a new fuselage,hopefully that will work.thanks,tom

No need to buy a new fuselage if its tail heavy. Just add some weight in the nose to balance it out. Unless of course you've made your tail REALLY heavy, then you would need a significant amount of weight up front to counterbalance...........
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