TRP

My Feedback: (1)

Greetings,

This weekend I was flying my Zagi (400x) at our local field.

I had put in three fights on it during the day and decided to take it up for one last flight.

I was soaring along, catching a good amount of lift here and there. After about 15 minutes of soaring I had worked my way up pretty high and decided that I should bring it down to a more sensible altitude. I turned it down wind and it really started to move. I was ripping right along and decided I should pull up a bit and level off... bleed off some speed. About the time I went to slow down I realized that the motor was on ( I could hear the faint noise of the RPMs SCREAMING) I chopped the throttle - at about the second I went to chop the throttle the zagi seemed to blow up.

I noticed the ailevons start to flutter.. and then the Zagi went crazy - it pitched forward and flipped once.. (the canopy flew off) it flipped again (the battery ejected like a rocket) and then the zagi floated like a leaf down to the ground. The impact from 200 or so (?) feet up didn't hurt the zagi one bit.

In all the excitement I didn't watch where the battery landed. ( I KNEW I should have attached the 5 foot long bright pink ribbon to the battery last night!) so the battery is a gonner. I found the plane and canopy no problem.

My question is - WHAT Happened? Maybe the esc was 'glitching' (from the overloaded rpms being generated from the monster dive) and the glitching caused the ailevons to flutter a bit (causign the violent spazim) and bucked the battery out.

How can I test my ESC to make sure I didn't smoke it?

Does anyone have any idea what may have caused the violent bucking? I know the ailevons were fluttering right before 'the accident' - but what caused that?

Thanks for your $.02,
Ted

mumblety-peg

My Feedback: (3)

Perhaps it's time to re-tape the ailrons? I see u have the 400 x. So I assume u used the carbon rod.

TRP

My Feedback: (1)

Mumblety-peg,

Thanks for the ideas.

The carbon rod is inserted in the bottom of the wing. Glued in.

The ailevons were double taped last month (tape on each side of the wing)

I did notice that after the accident that one of the servos was loose in the servo bay. I will have to work out something to snug the back up. Maybe a dab of 5 minute epoxy on the bottom of the servo to 'stick' it to the wing core.

Ted

Shadow Warrior

How old is your Zagi? I have seen older Zagi's do the flutter thing in a steep dive before. The main reason that I see is that the foam is old, broken or just weak in areas that at certain airspeeds the wing can no longer take the airspeed. The only fix that I have found is a total wing replacement. I have seen people try to add more tape or different mods but the flutter always seems to come back.

Matt Kirsch

My Feedback: (21)

Ahhh, the dreaded Zagi Flap... Been there, done that. Even new Zagis will do that if they're not built stiff enough and are flown too fast.

All aircraft will flutter like that if flown beyond their structural limits. A stock Zagi has no backbone at all, so flapping speed is very low. The 400X is slightly better, as it has a carbon fiber arrow shaft embedded in it, but it will still flap like a bird if pushed too much.

Some guys at http://www.yourzagi.com have gone beyond all reason with their Zagis, pushing them well beyond their original designs. These Zagis are fairly flap-proof, with 3, 4, 5, or more carbon fiber spars embedded in them.

jollyroger

My Feedback: (6)

Mine does that as well, especially since I replaced the stock speed 400 motor w/ the speed 480 reverse. This plane is fast enough for me, but it does the flutter jig when coming down from a loop. If I get a chance to re-cover the plane this winter I will install a few carbon spars or maybe some carbon tape.
I love flying this thing, totally addicting! Jollyroger

finchero

My Feedback: (-1)

first off are you talking about the zagi flap or a flutter(glitch) in your electronics. the flap can be taken care of with structural modifications, but a glitch is caused by excessive noise coming from the motor thus interfering with the controls. if your using a stock motor make sure you have the capacitors soldered to the pos and neg terminals on the motor. if you have a brushless system wrapping the esc receiver lead around a ferrite ring can help