I really need your help!!!!
 

Hey everyone, It's been a while since I've been on here, but I need your help desperately.

A bought a Great Planes Yak 54 e-performance series plane months ago and have had a blast with it ever since.

My problems are as follows:

1. I cannot move the battery back any further to move the cg aft, it is where Great Planes recommends it, but when I wish to do 3d with the plane, it is terribly unstable. I'd hate to add weight to it.... What do I do>>????[:@]

2. I am so unsure of what prop I need for the plane...I know it sounds crazy. My setup is as follows so please look over it and make your own judgments. I am a 3d flier, and take my planes to the max, but with this plane, I need to give the plane full throttle to even try to harrier, It's like I have the wrong prop or something. The plane is very unresponsive when attempting harriers, probably because the pitch of my props is wrong, even in high rates.

Ok, here's the deal: I don't have enough thrust to do any acrobatic maneuver, hover, harrier, waterfall, nothing. AND EVERY FU**** SITE OR PHONE NUMBER I CALL TELLS ME A DIFFERENT PROP TO USE. When I finish using my plane hard for 15 min, neither the motor or lipo is even remotely warm or hot. I had an 11X 4.5 great planes prop on it, but had no thrust. I read on GreatPlanes website that I should be using a 10X5 prop, so I bought like 10 APC props of various pitches 10 inches long. Never tried them flying, seemed like they could barely pull the plane. I need the most power I can get to do 3d!!!!!:eek: PLEASE HELPPPP!!!! I REALLY APPRECIATE ANY SUGGESTIONS!!!


Ok, setup I am running:

Great planes yak 54: http://www2.towerhobbies.com/cgi-bin...?&I=LXMUW7&P=7

Lipo: http://www2.towerhobbies.com/cgi-bin...0823&search=Go

speed control: http://www2.towerhobbies.com/cgi-bin...&I=LXLBR5&P=ML

Brushless Motor: http://www2.towerhobbies.com/cgi-bin...&I=LXLWT9&P=ML

Prop: http://www2.towerhobbies.com/cgi-bin...?&I=LX1556&P=7

Radio (not that it matters): http://www2.towerhobbies.com/cgi-bin...=LXHYK7**&P=ML

RE: I really need your help!!!!
 

Ryan,

First I think you should probably post in the electric power forum.

That said,
The most you can pull from that battery is 18 amps - max, ( and 9 volts min). I use the same size battery in my plane that is about half the weight of this one. I think you need a bigger battery.
The most your motor can handle is 20 amps, 296 watts.
The most your speed controller can handle is 25 amps.

You should not exceed these limits.

You are running the minimum size battery - the GP Yak link says 1250 to 2100 mah. You will need a power meter to check amps and volts and watts, but I might prop that thing up until you reach close to your battery limit. Regardless of the prop size, I do not think your battery will ever hit your motor limit of 296 watts, nor do I think it can deliver the kind of power you desire. Your existing prop may already be pushing it close to its limit - you will have to use a power meter to check.

Good Luck!

RE: I really need your help!!!!
 

Most of the time, the recommended specs on a plane are just enough to get it in the air. If you wish to do 3d, look at the recommended battery and motor sizes and use the max they recommend. That Rimfire with that battery and ESC isn't going to do wht you want it to do no matter what prop you put on it.

RE: I really need your help!!!!
 

If the plane is unstable it sounds to me that it is to tail heavy. Hard to say without seeing it fly. But if you have your battery where GP says to put it I am betting its to tail heavy. That battery you have is to light since it is a smaller size than recommended. If you had a battery that matched what the specs call for I think it would move the CG and it would be correct since the bigger battery would be heavier. This is just a thought but I would look at it.

The thing I noticed about these small electrics is that CG can be changed so easily without realizing. I had my CG bounce around by me just changing props sizes. There was a small difference in the weight between the props I tried. It took me forever to realize that my CG was off due to prop size. Each one weight different and was very noticeable on the plane in flight. I did not even stop to think of checking CG since I had done so already when plane was complete. After rechecking I was shocked to see how far off it was due to a prop swap. So I would just keep in mind every change to check the CG each time. Theres aren't like the big gasers which are more forgiving in that area.