AirCore 40 electric conversion any thoughts?

[Fishbonez]

I just attempted to convert an AirCore 40 and here was the maiden.

I am looking for some suggestions here. Could it be a thrust angle problem or maybe a stall because of lack of speed? It did take off the ground before I thought it would. Tail heavy? I balanced it as per the manual at the spar. I also built the kit as per instructions to include power pod. Motor was mounted on top of the wood provided for the engine. with a block of balsa as motor mount. I added no thrust angle only because the manual stated that none was needed. I know I probably should of added some but...
My set up is as follows:
Sky Power 60A ESC with Switchmode BEC
APC 11 x 7E Composite Propeller
Power Up 32 Sport Outrunner Brushless Motor
4S 3300 Battery

This is my first kit and my first conversion so any thought anyone may have will be appreciated
Thanks

 

[SnowRocker88]

Looked tail heavy. But, if you balanced it at the spar then it is likely something else. Sure the battery didn't shift after balancing?

 

[Fishbonez]

Thanks Snow. I Just double checked the battery and she is still nice in snug with the Velcro I used to keep it steady. Im thinking airspeed was the biggest problem at the moment but would love to hear all suggestions to see if someone see something I may not

 

[Foam Addict]

The Elevator looked to be at full up deflection throughout that maneuver, could something be slipping and causing the servo to Jam?

 

[SnowRocker88]

The Elevator looked to be at full up deflection throughout that maneuver, could something be slipping and causing the servo to Jam?

^^^This is the only other thing that makes sense.

How was the wind that day? Maybe get some more speed low to the ground and try to ease up on the elevator. Perhaps you just stalled it out. Or, like Foam Addict said, maybe you have a problem. Check your elevator function and throws and see if everything checks out.

Are you an experienced RC pilot?

 

[earthsciteach]

Bonez - when it came off the ground, did you push forward on the stick to get the nose down? If so and it didn't respond, I'm going with tail heavy.

The motor setup you have is pretty beefy at 88 oz of thrust. Nice! Do you know the flying weight of the plane?

Maybe I'll finish my Aircore 40 one of these days! Where did you get the kit?

 

[Fishbonez]

Thanks all.
I agree I think it is tail heavy. I have moved the battery more to the front and added about a gram of nose weight. I just may add more LOL. I also believe I was not upto speed before it took off. I was not expecting to lift off as quickly as it did. I think I may have been at 1/2 throttle. Just wanted to see if there was something I had not thought of. As soon as the weather improves I will go for it again.

Oh buy the way it was somewhat windy 10-15mph a slight breeze for Wyoming.

Teach I got the kit from a club member who was cleaning out his storage area and thought I would like to have it for a winter build. It was 90% complete so I had to use some leftover parts. All I have invested in it was the electronics and servos. Overall it was an easy build except for the instructions. Mine were pretty old and seemed a bit vague at time. As it goes with Murphy's Law I found an updated version of the instructions after the build was complete :black_eyed:

 

[earthsciteach]

My instructions say that the plane should balance 3 degrees nose heavy (ish, I'm sure) when the plane is supported under the spar at the wingtips.

 

[Fishbonez]

My instructions say that the plane should balance 3 degrees nose heavy (ish, I'm sure) when the plane is supported under the spar at the wingtips.

Thanks Teach,
Well that seems to be where my balances at. Given the fact I'm crossed eyed and math ignorant I think I'm pretty close. :black_eyed:

 

[earthsciteach]

Well, that's not what I wanted to hear. Was hoping you would say the current cg is about 3" aft of the trailing edge. LOL

So, do you think you just pulled it off the ground too soon?

 

[Fishbonez]

I think so and a bit tail heavy. Just waiting for wind to cooperate. Either too windy and windchilly or light winds but not above freezing. Gotta love Winter.

 

[pgerts]

THAT was a stall due to pulling the plane up without any speed.
The aircore planes are a lot heavyer than the DT planes and need a lot more speed.
Trying to get up and hover that kind of plane at a maiden is --- perhaps interesting ;-)

 

[Fishbonez]

Small update,
After taking all advice from here and other sites. I repaired the Aircore added a touch of nose weight and some down thrust and here was the results. She really needs a lot of trim wanted to go right and could not get her in trim she also still wants to climb so will need to do some more trimming there as well. I did lose all left aileron and it did not seem to respond to rudder. I then tried to move right but she began to get away from me and while attempting to turn right again she stalled and down she went.

Still have a long ways to go but we are getting there

 

[MrClean]

Hang that airplane from the ceiling with the wings level. Hang a plumb bob from the same point above the airplane and let the plumb bob show you where the currect CG of the plane is. Both for-aft and port-starboard. Adjust it to where the CG is SUPPOSED to be.

On a level and flat surface in flight condition (wing firmly affixed) measure the height of wingtips front and aft and of tail surfaces. Also measure all control surfaces. If it isn't tail heavy and way heavy on the right wing, then you've got a warp or mis-alignment.

Your video says that all is repairable BUT if you have something so out of square you may need to rebuild.

You can get plans for a SPADLT40 at http://www.spadtothebone.net/SPAD/Spadet/
And SPADstick at http://www.spadtothebone.net/SPAD/SpadStick/

Both planes use the same gear, use more modern techniques and fly much better then their AirCore predecessors. As you've seen from building the AirCore planes, the construction methods pretty much mirror building with Foam board save the material is water and fuel proof from the get go though a little more fidgy to glue.

Make sure it's straight, that the wing and tail is on level and correct. If something is horribly wrong replace that part OR the whole thing.

 

[earthsciteach]

Do you still fly SPADS, Mr. Clean? Very much like foam core, but nearly indestructible, I'd imagine.