EZ pack wing incidence vs COG?

[Foamforce]

I’m converting chuck gliders to 2 channel with ez packs. To get it to ascend under throttle, I’ve been either moving the COG (battery) and/or slightly adjusting the effective angle of incidence with rigid elevators. I’m unclear about which I should be doing under which circumstance. It seems to me that elevator will only be effective at higher speeds, so that’s what I would adjust so that it climbs at throttle. So would I adjust the COG so that it doesn’t dive at low speed, and then add a small amount of elevator so that it pitches up at higher speed? If I glide test it, should it pitch steeply up with a hard throw and then level out?

Or should I be leaving elevator completely out of this, beyond whatever amount of angle of incidence is built into the original design, and only move the COG back to get more lift under throttle?

Fwiw, I was playing around with FT’s Typhoon chuck glider and had moderate but inconsistent success. I’m thinking of trying with one of Nerdnic’s excellent F16 chuck gliders next.

 

[L Edge]

Quick story-- I have EZ pack V2 and had a fly away due to high winds. Essentially, adding power caused it to climb, result, wind moved it downwind further away. Back off power and it nosed down, even tried tacking the wind, so it blew away over the hill and was lost.

If you do nose up by power(aft cg), and then have large elevator movement to overcome throttle at any position, and by perhaps tacking, you might be able to prevent losing or damage to plane.

 

[Foamforce]

Quick story-- I have EZ pack V2 and had a fly away due to high winds. Essentially, adding power caused it to climb, result, wind moved it downwind further away. Back off power and it nosed down, even tried tacking the wind, so it blew away over the hill and was lost.

If you do nose up by power(aft cg), and then have large elevator movement to overcome throttle at any position, and by perhaps tacking, you might be able to prevent losing or damage to plane.

I’m not quite sure what you mean about having an elevator movement to overcome throttle. Do you have a functional elevator on yours?

I know one of the issues I have with the two channels is if I have to turn during my landing, it can cause it to massively balloon. Similarly, if there’s much wind, then I can’t get back to my position because fighting the wind just causes the plane to go higher. Only way to get down is to either let the wind carry it away or try to spiral into the ground if possible.

 

[L Edge]

I’m not quite sure what you mean about having an elevator movement to overcome throttle. Do you have a functional elevator on yours?

I know one of the issues I have with the two channels is if I have to turn during my landing, it can cause it to massively balloon. Similarly, if there’s much wind, then I can’t get back to my position because fighting the wind just causes the plane to go higher. Only way to get down is to either let the wind carry it away or try to spiral into the ground if possible.

I assumed you have the earlier version with the elevator(servo). Sorry, but you are experiencing what happened to me.
Did you notice that when your throttle is almost shut down or completely off, the differential throttles go full bore? (reason why it climbs)?
There is a point where a slight throttle keeps it going and the differential thrust works properly. Under that, touch the diff stick, and it winds up in rpms.

Given that, now you have to find the sweet spot of moving the CG ahead so that it still climbs, but not as much as before.(for the turn or into the wind). I built four different types and each one acts different due to frontal drag. Found the throttle is very touchy to get a glide into the wind or it ends up climbing. Also, as battery wears down, the throttle magic spot moves slightly forward to have it fly level.

 

[Foamforce]

I hadn’t actually realized what was happening with low throttle, but now that you mention it, I think I was instinctively maintaining very low throttle while gliding in to land in order to maintain directional control without ballooning. I’ll think about that next time I fly and see if I can confirm.

With regards to the COG, is your advice to not use any elevator trim and only adjust the COG to achieve elevation control?

 

[Foamforce]

On a side note, I’m considering setting my my Guinea Pig as a two channel, just for giggles. I think I can set up my TX16s so that I can toggle between normal AETR and 2 channel mode so that I could take off normally and then switch to 2 channel operation when I‘m at a safe altitude. If it went really well, then maybe I’d try landing that way too. I have a long runway, so speed isn’t a problem, but I’m not sure how much roll control I’ll have. I don’t understand how straight wing 2 channel planes roll, but I’ve seen it before (e.g., the mini Noob Wonder) so I assume it works somehow. Correct me if I’m wrong!

 

[L Edge]

I hadn’t actually realized what was happening with low throttle, but now that you mention it, I think I was instinctively maintaining very low throttle while gliding in to land in order to maintain directional control without ballooning. I’ll think about that next time I fly and see if I can confirm.

With regards to the COG, is your advice to not use any elevator trim and only adjust the COG to achieve elevation control?

I myself, when I designed the 4, did not need any elevator trim. Noticed Josh added elevator trim to the Eagle to get it to work when building it.
End result, certain models may need it, so try it and see if it works.

 

[Foamforce]

Did you notice that when your throttle is almost shut down or completely off, the differential throttles go full bore? (reason why it climbs)?
There is a point where a slight throttle keeps it going and the differential thrust works properly. Under that, touch the diff stick, and it winds up in rpms.

Holy smokes, you’re right! I was messing around with it and when the throttle cuts the differential thrust goes full power! Very dramatic.

I’ll bet that’s why I had a few bad landings. I would come in and make an adjustment in the last few feet and the plane would go to full throttle and balloon.

I’m going to see if I can use this in flight to make sharp turns when necessary. I’m also going to try to maintain minimal throttle on landing.

 

[L Edge]

Holy smokes, you’re right! I was messing around with it and when the throttle cuts the differential thrust goes full power! Very dramatic.

I’ll bet that’s why I had a few bad landings. I would come in and make an adjustment in the last few feet and the plane would go to full throttle and balloon.

I’m going to see if I can use this in flight to make sharp turns when necessary. I’m also going to try to maintain minimal throttle on landing.

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