Cox-powered Zagi?

[wrenwright]

I figured I would put this post here first and see if anyone has any input. If not, I'll try over in the Flying Wings forum.

Has anyone here ever put a .049 on a Zagi-type wing? I have several wings sitting around and a few old engine from when I was a kid.

Any comments?

[Dave Campbell]

I've seen it done with a Norvel .074, was supposed to be waaaayyy better in the air than the stock powerplant.

Dave

[wrenwright]

Dave,
I'm sure it was. The stock 400 is a real dog on this wing. A terrible match.

[RICH S]

I put a Norvel AME .061 on one with an attached plastic tank/mount. It really screamed, faster than a 3 turn BL system. I put bowling ball holes on the bottom for launching. Probem is, with that pusher prop it got too hot after about 10 min., but it sure was fun.

[wrenwright]

Rich,
What prop were you using? How many rpm's were you getting?
Thanks.

[wrenwright]

I fired up my old Black Widow that hasn't been run since 1983. What a pain. I finally got the thing started, but I think it's better to put it back on the shelf and go back to electric. If the battery is charged, the thing runs. Simple as that.

[Dave Campbell]

If the battery is charged, the thing runs. Simple as that.

That's 'cause you aren't pulling enough amps yet. ;)

This last week or two ago I was setting up a plane and cycling new packs to get their capacity up. This was a sport F5D setup, B40 sized HiMaxx, 70A controller, GP3300 cells and a 5-5 prop. Turns out that the prop was a little too big (I knew it was but just wanted to cycle the packs a bit) and it was pulling 83A on partially charged packs. The shrink-wrap on the battery packs wrinkled up and split, as did the speed control, and the controller shut the motor down after about 15 seconds of run time.

But ohhhh what a 15 seconds!

Dave

[wrenwright]

Lordy. I'm trying to like 1/2A engines, but I keep having flashbacks from when I was a kid....We usually gave up on the things and flew our rubber-powered ff models or HLG's.

[Dave Campbell]

Well, as with all niche areas of the hobby there are special ways of doing things and techniques that have to be observed.

With 1/2A motors the two biggest things to consternate a guy are fuel and glowplugs. The fuel has to be clean and dry. I can't stress that part enough. The engines are very easy to overprime because a drop of fuel doesn't scale down like an engine does. Needles have to be set a few more clicks to the rich side because they unload so much in the air compared to a large glow sport motor, etc. With the plugs, they have to have good voltage. People who fly 1/2A a lot consider Cox glow heads to be 3v plugs..

It's all technique...

[rlcout]

I get a .049 powered Zagi!!

Check this out!!!

[Dave Campbell]

rlcout: Try an APC 5.7-3 on that motor-I think it would be a good match!

[rlcout]

Dave Thanks!!!

Do you think that will be more fast?? (ohh my God!!)

[wrenwright]

Any idea of the rpm's you're getting?

[Dave Campbell]

Definitely faster.. straight-bladed props are best for stirring paint in the can! APC makes a few good 1/2A props, the 5.7-3 is one of the larger ones... I suggested it because the TD has fairly mild port timing (compared to a Norvel, VA etc.) and they like larger props. A little experimenting might be fun for you-the props are $2 here in the USA.

Dave

[rlcout]

wrenwright,

I have no idea about the rpm's. I'll measure.


Dave,

Man... my zagi flying with 6x3 is a little devil.. very nervous.. a little touch in the stick and she changes the direction like a missile. I cant handle that more fast (I guess not). :)

How I flew my zagi this weekend:

That small tank have fuel enough for 3 or 4 minutes. I threw her and i got up really fast. When the fuel finished, I started to glide (I like that) but I lost the control and I hit the tree.

Belive or not!! I lost only the propeller!! Figure out if I do that with my plane???

That is what I like in zagis!! :)