capn crunch

I am sure that a lot of you Zagi 400 buffs have had slight problems with the less than totally precise handling of the Zagi 400. I have had an awful lot of fun with two of them that I have literally battered to bits, but with the third one I thought that I would address two problems: a) the elevons were real wimpy, and tended to throw differently from tip to root. b) after even a little abuse,. the idea of "sinking" the servo into the foam meant that the servo was moving around, resulting in even less precise control.....

So I tried the following.....first I took a dremel sanding drum and gently cleaned out a servo space on each wing, being careful to get a flat bottom to the access. I then glued liteply plates to each of the servos and epoxied them to bottom of the servo access. Presto: we have servos that are rigidly installed in the foam wing. I then took a balsa stick slightly wider than the foam trailing edge, stripped off the colored tape covering the trailing edge, and glued (hotstuffed) the balsa trailing edge to the reinforcing tape on the foam trailing edge. I then sanded the balsa flush with the other side of the TE. I placed the exising elevon over another 1/16" balsa sheet and made another template and glued the two 1/16" sheets together. Presto! non-wimpy elevons... Instead of the top hinging that the stock aileron used, I used center hinging with EZ hinges. The gap was minimal, and the control surface was rigid.

Flight tests indicate double the control sensitivity, increased flight duration, and we added about 1 oz to the weight of the model. Roll rate is awesome, in fact the elevator travel is excessive, and we are trying to reduce it...at low power setting the model is very controllable and predictable....which was what we didn't have with the stock setup.

I am not knocking the original design of the Zagi. Given a very good builder and a new model, my mods would not be appreciably that much better. BUT after use and abuse, the mods will keep the model flying better longer....

I would appreciate your comments


Capn Crunch

AMA 87012

latch66

That's interesting. Sounds like the mods worked for you. Keep us posted on how they handle use and abuse. They should hold up well.

My Zagi is down right now due to a high speed inverted pass which ended due to a brain fart.
(It actually was neat to see the wing itself "bounce" three feet in the air when it hit terra-firma. Like I said, it was moving!)

My Zagi came out of this with minimal damage. It just needs a new canopy, tray, and recovering. No other damage.

But, my Zagi is not stock either. It's brushless powered and has a flat carbon fiber spar system in addition to the standard round spar. This forms an A-frame spar on top of the wing. Very rigid. This increase in strength also helps to avoid the Zagi Flap.

AMTdude

This setup flew great right off the bat with no trim inputs necessary....

here are the specs...

Wingspan:48"
Length:42.5"
Weight:2.4Lb.(rtf)
2 JR nes 241's for the Ailerons
1 JR 3421 Digital Mini for the Elevator
JR 610M Reciever
The motor is a 12 year old Race Prep Modified 14Turn
8x4 carbon fiber prop (will be 7x6 APC next Flight)
E-flight 16 amp Speed Control
Electro Dynamics KR-1400AE 9.6v NiCd
2 carbon fiber arrow shafts in the booms

35-40mph level in level flight
3-4min. flights (depending on amount of wind)

14 hrs. building and designing using the T.L.A.R. method
(That Looks About Right)

The "blueprint/plans" was a couple pictures from bvmjets.com

Rodney Evans-Parkersburg,WV