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Old Nov 07, 2001, 02:03 PM
Registered User
Pasadena
Joined Oct 2001
343 Posts
MM Zagi Flap

Help..... I was diving my MM Zagi this morning from 2-3 hundred feet and the wings began to flap towards the tips. It looked pretty weird! I pulled up and cut the power for awhile until my knees stopped shaking.
I'm currently running with just the basic 400X spar.
Any ideas? Is their a longer carbon fiber spar I a can purchase somewhere or do I need to add more spars of the same length along the LE of the wing? With this motor, weight is not really an issue.
FYI batteries do make a big difference. The CP1300scr's are really a lot faster than the original 1700au's.
It's amazing how quickly your eye and thumb gets used to the added speed.
I never would have gone for the death dive just a couple of weeks ago! I was the guy running the MM at half throttle.
Does this mean I'll be buying a Bandit Hotliner soon?
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Old Nov 07, 2001, 07:24 PM
Single-task at best...
tim hooper's Avatar
Telford, UK
Joined Feb 2000
7,507 Posts
Re: MM Zagi Flap

Quote:
Originally posted by Waxer

Does this mean I'll be buying a Bandit Hotliner soon?
Very probably!

My own cobalt-Zagi also began to flap, in spite of the 12" cf spar. As I couldn't face digging out the existing spar, replacing it with a longer one & recovering the model, I hit upon the following;

I got 2 lengths of 3mm cf, each about 22" long and epoxied these into grooves - one on each wing top surface - on the joint line between the two kinds of foam. They run from the battery tray to the tip, and appear to be just a black trim line. No more flap!

Incidentally, between the Zagi & the Bandit, I'd suggest the Mark Rittenger-designed Sportwin, to get used to small, fast models!

tim
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Old Nov 07, 2001, 08:38 PM
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mtayl's Avatar
Boulder, CO USA
Joined Sep 2001
1,405 Posts
I'm probably going to face the zagi flap as well. Is there an online store which sells CF spars?
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Old Nov 07, 2001, 09:58 PM
Flying slowly along..
Northern Ca.
Joined Dec 2000
1,336 Posts
Don't say I didn't warn you. Two more spars, one along each wing leading edge will solve this problem. www.acp-composites.com has them for cheap. He usually has close out spars for about $1.00 ea. E mail or call and ask for George and tell him you're looking for Zagi spars like Trick buys from him. He'll know what you're talking about.---Rob
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Old Nov 07, 2001, 11:00 PM
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Woburn, MA, USA
Joined Jul 2001
624 Posts
Slow down and it won't flap ;)

Happened to my FMA Razor once. For some reason, a bunch of people were looking at the Razor while doing a high speed dive. People said it looked real weird, the way the wings seemed to be rippling. The refection of the sun off the wing made it look like little waves of water were flowing from the LE to the TE. At the same time, the wings were starting to flap.

I was mesmerized by the weirdness of it and kinda forgot to slow down and pull up until people started yelling "Hey! Wow! look at that". Had no visible damage, but after that, I decided on a VNE of 55 MPH. After all, it is a big draggie Foamie.

Rich<>
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Old Nov 08, 2001, 02:22 PM
Registered User
Pasadena
Joined Oct 2001
343 Posts
MM Zagi Flap

Thanks for the info gentleman. I have found to cf spars that are the same size as the 400x center one. I will just add them to the LE.
Tim, when you buried yours near the epp, the two types of foam didn't begin to separate did they? Or did you make sure and bury the spars more into the reg. foam? Also, it's been fun reading your Bandit threads. I'm guessing you don't run the motors the full flight like with the Zagi's but you reach your height level and then shut down until you need to head back up? I've never seen a hotliner fly before so I don't know the drill.
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Old Nov 08, 2001, 02:26 PM
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Alan W's Avatar
NY
Joined May 2000
2,274 Posts
Zagi Flap Video !!

Whats really cool about this clip is you can actually HEAR the wing "WhopWhopWhop" when it flaps....

http://www.squid-ink.com/hpn/rc-photos

and scroll to the bottom right video

Alan W
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Last edited by Alan W; Nov 08, 2001 at 02:30 PM.
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Old Nov 08, 2001, 02:34 PM
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NoCal
Joined Sep 2001
72 Posts
OMG!! that must've freaked you out just a bit. I can't get over how loud the flapping sound was!

B
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Old Nov 08, 2001, 06:38 PM
Single-task at best...
tim hooper's Avatar
Telford, UK
Joined Feb 2000
7,507 Posts
Re: MM Zagi Flap

Quote:
Originally posted by Waxer

Tim, when you buried yours near the epp, the two types of foam didn't begin to separate did they? Or did you make sure and bury the spars more into the reg. foam? Also, it's been fun reading your Bandit threads. I'm guessing you don't run the motors the full flight like with the Zagi's but you reach your height level and then shut down until you need to head back up? I've never seen a hotliner fly before so I don't know the drill.
Waxer,

The 3mm cf rods lay flush with the surface of the wing, and are quite visible appearing to be a thin black 'trim-line'.

At a tangent, thanks for following the Bandit threads!Yes, it's a new discipline; full throttle for 10 secs or so to get the plane from ground to a smallish dot, then cut the motor to perform aerobatics on the glide or hunt for lift. The only time I use part-throttle is on launch itself, and as soon as the plane has accelerated a little it's full-throttle and point the nose up!

The CP1300's are great cells. How did you fit them in your Zagi!? I use 8x800AR's in mine.

tim
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Old Nov 08, 2001, 07:37 PM
Registered User
Pasadena
Joined Oct 2001
343 Posts
CP 1300 scr cells-mm Zagi

I had them built by New Creations R/C. We put 5 cells on the bottom and three on top. I then put the heavier side towards the front of the plane. With the MM motor, I push them all the way to the front of the 400x Zagi cut-out.
Note: I replaced the 400x tray with the 600 FMA Razor tray. The motor fits perfectly. I then dug out the battery area in the wing so I could place the batteries deeper into the wing. This helped the aerodynamics a bit (I think)and it also changed the balance(the weight was not riding so High) so the plane handles much quicker then the normal 400x. The response seems much quicker when I want to turn or do a trick. I also used the FMA canopy which is much lower than the 400x.
Regarding the Bandit. So you fly it like a sail plane. Does the plane hold the energy after a small dive so that you're not forced to dive, do a couple of tricks and then have to then climb all the way back up? When I checked out the video of the Bandit, I heard the engine during the duration of the whole flight! The plane was also not flown that high. Your thoughts!
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