well, i was sloping with my zagi the other day and wind was out of this world. i was going to fast for a banked turn and smack. canopy was busted and battery lost. other than that no real damage. i installed a new tray and canopy and built a new battery. assembled everything correctly. only thing different is that i tried a new winglet design where some hangs below the wing as well. i heard its more stable and should be better for turning, so why not try it out. went back to a field, made sure everything is fine, CG is good and so on... i throw and fly and this is what it does. flying into the wing, it barely moves, almost still and shakes around like crazy. keeps flapping and throwing all over the place. flying against the wind, it seems like its dying to fall and have to apply full elvator while turning! flys very crappy, any ideas? played with the CG alot and it doesnt help. is this a sign of the foam softening up?

2 thoughts,

Damaged servos or some slop in your control linkages ?.

Elevons damaged or control horn attachment ?.

elevons are fine, so are the horns and servos... however i have a little slop in the linkages, i hope its the problem, ill fix that.

Originally posted by compuatic
....however i have a little slop in the linkages, i

Man I have had so much slop in my Zagi and it still flew fine...A little out of trim, but still flew.

I've had my tape some loose from the top of the wing, and hence the taped on aileron. The enitre top of the wing was flapping around like crazy .No problem

Once had about 1/3 of the aileron at the tip bent up from a mid air. Fly a little cock-eyed, but I jyst kept flying.

Had the entier motor tray come un-taped and it would flap around when pulling Gs. Some weird pitch stuff, but it still flew fine. I know you are un-powered, but even with this mass shifting around I noticed no real problems.

I have since quit trying to re-re-attach the wing tips after our mid-airs ( we average 8-10 a flight) so I just leave them off. No problems noted.
etc....

It would be interesting to see what solves your issue. All I can say is I have never seen a plane be so mis-shapen, and still fly just fine.

Originally posted by rcav8r2
Man I have had so much slop in my Zagi and it still flew fine...A little out of trim, but still flew.

Ya, mine too, so it's probably not slop.

You mentioning loose tape brings a memory, had missed a half split tape hinge once that made it fly real weird. Actually missed it twice, the second time after landing to check it out, didn't see it and chucked it up again.

actually mine is a 400x so its powered, however i usually go sloping with it with no probs. after fixing, i tried flying in a field to trim and this is when i noticed the issues, its really weird. the thing thats really annoying is when i turn out of the wind and it wants to fall very quickly and goes very fast, which forces me to immediately turn back in the wind to avoid collision to the ground. ill try messing some more with the CG as well.

Most of what you describe sounds like it is tailheavy, but after some crashing the nose gets upturned and maybe a little washin develops in the tips which will give you major tipstall. Always keep your bottom wing beds so that you can recover or reshape the wing to the original shape by either retaping or maybe a little heatgun action. If it is just not penetrating and is very squirly, that is typical of being tail heavy, add weight to the nose until it becomes sluggish and then backoff until it feels good. This is all trial and error and you will get a feel for it when you see it in the future. No one can really tell from afar, so put the wing back in the beds, check for correct airfoil shape and then start back at the recommended CG. Also fingers are not really a good thing to use for cg. Use some sticks with a smaller contact area such as a couple of bamboo skewers with the blunt end rounded off a bit to be quite a bit more accurate.
Welcome to the black magic of plane trimming, just try everything and pay attention to the results. Above all have fun! And don't get discouraged.
And what the heck, to minimize variables, put the original winglets back on, doubtful they are a much of a problem if they don't go back farther than the ailerons, but changing only 1 variable at a time is a good thing.

yeah i figure it felt like a CG problem, even thought the battery was all the way up front. maybe its because my bass elevons are slightly heavier than balsa, but with theyre area, they can offscale the CG. ill mess around with it. thanx everyone.

Dump the basswood elevons, go back to balsa and sand them down to a nice thin TE for a good airflow. Weight aft or outboard is an enemy. If you want strength, glass the elevons, they will outlast your plane and you will probably move them on future Zagi's. Even just painting on a bit of waterbased polyurethane and then covering them with 1/2 or 3/4 oz. glass cloth is not a bad thing. I am a firm beleiver in a clean airfoil, and have gone so far as taping some 7/11 coffee stir sticks to the LE of the coroplast winglets to make a better entry. Go get a cup of cofee, pocket a couple of stir sticks, and back to the slope!

Though not a Zagi, my Boomerang began to fly awfully.

After checking all of the points already mentioned, I noticed that the joint between the two panels, was loose ! ! !

No doubt the numerous impacts with terra firma will not have helped in that department !

It is now in the 'repair shop', for reassembly and recovering !

I might as well make new balsa elevons and corroplast tipfins, while I'm at it !

Keven.

If the cores need regluing, I would strongly suggest to cut 4 inches from the center of each panel and making a 40 inch Zagi. On the slope it behaves much better than the 48 in. The preference to 48 inches is due to slope combat rules. If you don't plan to enter any combat events then start hacking the cores. You can still combat with the guys at your slope.

I think you have a combined problem:

1. wing joint has delaminated

2. winglets are not adequate and don't provide enough directional/lateral stability.

I found it helpfull to slightly modify the coroplast tiplets by simply removing 1/2 of the inner ribbing of them and then applying 3m 77 on the innner surfaces of them and joining them together. This gives you a clean aerodynamic shape on the coroplast edges instead of a bunted/hollow edge.