Doing something wrong with motor combo I believe. Please help.

[J-J-P]

I have something very wrong with my setup I believe. I am a first time pilot/builder(ton of simulator time.) I have built ~15 airframes, even tried just motorizing 4 different $15 chuck gliders. I have purchased an electronic package from my local hobby shop; The salesman tells me that it should be more then enough for what I am doing. my electronics are as follows.

2s 1300mah li-ion battery. (from old helicopter)
tactic ttx610 w/6channel receiver.
1 40g servo(not used)
1 10g servo(not used)
1 9g servo (used for ailerons)
2 3.7g servos for rutter and elevator.
6amp esc w/bec
10g 18-11 2000kv motor.
I have tried 6x5 prop(comes with electronics) 6x4 7x3.5 8x4.3 5x5 4.5x4 5x4.5

current wingspan is 22"
length is 24"

I have tried so many combinations of wingspan(22-60), length, thrust angles from down, natural, and up; even just buying working gliders(both 37" and 48" WS) and adding the electronics into them.

The problem I am having is the planes will fly just fine with the battery installed but unplugged, no prop, and just chucking them, but with the motor on and trying to fly it, I can't get farther then 30 or so feet. The plane will just pitch up and stall and fall nose first into the ground. I have attached pictures of the current airframe, which is the closest I've come to it actually flying when it was at 100% throttle I was able to ease into a landing. I can't seem to figure out what is going on, weather it is under powered because of one or more of the parts; although the parts are suppose to match and even be a tad bigger then the FT Power Pack A.

Any help would be greatly appreciated, I am learning all of this with my step son and I think it is becoming disheartening for both of us to put all of the work into them and they just crash and ruin parts. I keep pulling all nighters to be able to surprise him (and mom who has yet to complain about all the money I've spent) but with no luck. unfortunately I thought that by being able to build the planes it would take all the intimidation of crashing, I know we will both crash many times on our journey learning to fly. But I am hundreds of dollars in, and I really do not have much to show for it. His birthday is in a week, and I would love to be able to surprise him with something that does fly rather then another almost total loss of parts.

 

[J-J-P]

BTW the motor/6x5 prop/esc/3.7g servos were all in one matched package.

 

[billms@gmail.com]

Dumb question: with 2s you should be getting 7.4v - is that enough for the motor? Might you be getting just enough out to pull the nose up then crap out to a stall?

 

[J-J-P]

never a dumb question... Thank you for replying. I actually thought maybe the battery was too large and the weight was the issue. its li-ion so it is very low weight, and has 8.8v. I am not completely sure if the 2s setup was enough(basing a lot of trust on my local hobby shop), but I was shooting for the FT A Pack, used on the simple solar with a 2s 800mah. But it does exactly that, puts the nose up, then stalls and falls nose first into the motor.

 

[J-J-P]

I feels like it is under powered, but I keep getting assured that it is more then enough, and not to over power the plane.

 

[Ron B]

I know nothing of that electronic set up but if you can fly it for about 30 ft it may be that you are giving to much up elevator and stalling it so you may try just a very little elevator at a time and a LOT of room in front of you and see if that helps. A big problem with starting out is over controlling.

 

[J-J-P]

Thank you for the reply. I am able to control the plane when I just chuck the plane with no prop on it, the problem only comes with the motor on, thats what is throwing me off. I assume that the most of the 30ft is me just throwing it.

 

[J-J-P]

its almost like the motor adds drag. it will glide almost better then it will fly. with the motor on it just wants to climb, then stalls. I have tried low rates, and the elevator has very little throw. 20 degree max, it does not have the authority to even level out after the stall. also it does not stall in a vertical attitude, it is ~45 degree, then falls straight down.

 

[J-J-P]

is it possible that the ESC will not push the amps required for the motor? I am new to brushless, I have no clue what the amp draw should be.

 

[Foam Addict]

A 2s 1800 is a lot for that little plane, and being a Li ion might not be able to handle the current demands of the motor. I would go to a 500 2 cell. Also, if you can make your fuselage a little smaller in Cross section that might help. you don't have a ton of power to spare, so you might be loosing a lot of thrust to drag there. Just for grins, is your CG between 1/4 and 1/3 of the way back from the front of the wing? I would move the CG forward based on what you're describing, that sounds like its tail heavy. Gliders can get away with a super far aft CG, but as soon as power is added, they can go out of control just like you describe.

 

[J-J-P]

the CG is 2.5" back on a 5.5" wing with 1" ailerons. I am not sure if I should count the ailerons as part of the wing or not. BTW, the wing is constructed the same as the pic, but smaller. sry posted wrong pic. the li-ion could be the issue, but it came from a heli.

 

[Foam Addict]

That's a little far back, I'd move it forward to 2" if you can. also whats your AUW? (All Up Weight if you didn't know.)

 

[J-J-P]

Thank you for your time and help. I don't have a scale that will measure it. but the battery is 89g and the plane may be 1/2lb at most. I can not register it on a bathroom scale. but I honestly have no clue. its 1.5 sheets of foam board, 2 glue sticks, little tape. in my hands it feels less then the battery.

 

[Foam Addict]

That makes sense, a 2s 1800 weighs quite a bit for that plane. I think if you're AUW is less than 10 oz, you should still be fine, though really anemic on power.

 

[J-J-P]

im sorry it is a 1300mah

 

[J-J-P]

What would you think would be the best prop to run with this setup? the motor/esc came with a 6x5 prop. 8x4.3? 7x4.3?

 

[Foam Addict]

I'd actually go with a GWS or APC (or similar light weight prop) 6x3 if you can get your hands on one. That 6x5 is almost certainly drawing to much current, as that motor can only handle about 3.5 amps.

Still, that's a lot of battery, most planes like this would use a 2 cell 350 mah lipo. It still might work though.

 

[J-J-P]

Thank you everyone very much for your help. I am currently building a new fuselage that is 1/2" narrower, and trying to cut weight everywhere I possibly can on the whole plane. I will correct the cg. This is the only battery I have at the moment, I made the new fuselage just fit around it. hopefully I can shave 30-40g to make up for the battery. I will post my progress and the outcome as soon as it is finished.

 

[Ron B]

if you can go to a lumber store that sells nails and screws by the pound and try to weigh your plane with out the battery and then with it and see what it weighs or go to the post office and see if they will weigh it for you. I live in a small town and our postal people are super nice they can't weigh grams but to the .01 of an oz then if you want grams just multiply oz by 28 and you will have the grams.
Now that you have the weight of the plane you will have a better idea as to what size motor you need.
If you can get the thrust of your motor that will help to determine if motor is to small and also how many amps it draws. It all came off of a unit that was manufactured so they should all be compatible but may not be enough power.
Now are you putting the prop on so the numbers are facing forward?

 

[J-J-P]

Yes the numbers were facing forward. The battery is too big for everything else being too small. I built a new plane with a further forward cg, and I was able to cut ~37g off the plane. It fly's much better, but only has enough power to hold itself up enough for a gentle landing. The motor looks to be about 1/2 the size of a blue wonder. I think I may need to take a break for a bit until I can repurchase the electronics again. If my motor/esc can help anyone out there Id be willing to donate them to a good cause.