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Futaba-RC . A Main Hobbies . Boca Bearings

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e-Lite Machines Corona > mega 16/15/4
 
 
draganflyer
Heliman
Location: Calgary, Alberta

I have a mega 16/15/4, with 7 cell 3300mah NiMH pack, and although I seem to have tons of headspeed, I can only get the heli to skitter around, no hover, no lift.

Any ideas? All would be greatly appreciated!
Wayne
11-08-2003 Over year old.
 
 
elicopter
Heliman
Location: emerson new jersey

I think the 4 turn requires more voltage than a 7 cell
I use oone on my corona and that's because i am using a 10 cell equivalent lipo 3s4p
11-09-2003 Over year old.
 
 
Wright Flyer
Heliman
Location: Finchingfield, England (UK)

Wayne,

The Mega usually used in the Corona (with the standard 9 tooth pinion) is the 16/15/3, not the 16/15/4. The Kv of the /4 is only 2,200 while for the /3 it is 3000. So you'll need to change your gearing in the same ratio - 1: 1.36

I always get it the wrong way round but I THINK this means that rather than a 9 tooth pinion you'd need 9 / 1.36 = 6.6 teeth but it could be 9 * 1.36 = 12 teeth. If the latter you may be able to find a 32 pitch 12 tooth pinion but if the former then you've got problems as I think 8 teeth is the smallest you can get. In this case, as "elicopter" says your only hope is to use far more cells (7 cells * 1.36 = 9.5 cells - so 10 cell packs should be about right).

What made you go for the /4 rather than the /3 ?

Cliff
11-10-2003 Over year old.
 
 
draganflyer
Heliman
Location: Calgary, Alberta

Mega problems

Thanks for the info!

As for why I went with the 4 instead of the three; bad information from the LHS. I went in asking for a 3, and was told by the guy that's the "helicopter expert" (in this case, my definition of "expert" comes to mind; "X" being an unknown quantity and "Spurt" being a drip under pressure) told me that the 4 would offer me a lot more performance for the same buck.

Short of taking it back and force-feeding it to their "expert", then waiting for God knows how long to get a 3, what are my options? I have numerous 6 cell, 1500mah NiCD's from my R/C tanks, can I double these and make use of them? If so, how would I accomplish the wiring to make it work?

I also have a couple of 3 cell, 2100mah, 11.1V Li-poly's for my Draganflyer IV. Are these possible replacements?

Sorry for the dumb questions, but I'm brand new at this "one big rotor instead of 4 little ones" thing!
Thanks
Wayne
11-10-2003 Over year old.
 
 
Helicat
Heliman
Location: Wichita, Kansas

I ran the Mega 16/15/4 using a sanyo 1900scr thrust pack on a cc speed controller. Using the 6 degree pitch blade grips and a 9 tooth pinion gear it had good time around 8 or 9 minutes depending on the style of flying. The only concern was that the rotor speed was slower than some people would like which made the cyclic and tail response slower. I do not know which esc you have you might check its setup. Check for binding and gear mesh . My Mega broke internally after a minor setdown not a full blown crash. I have presently go to a atomic force until I decide which brushless to go to for better reliability. If you will post some more info on your setup I will see what else comes to mind . Helicat
11-10-2003 Over year old.
 
 
draganflyer
Heliman
Location: Calgary, Alberta

I'm using a jeti 30 , and the only thing I've done to it is disengage the brake. Gear mesh is good, no binding, everything else is as tight, or loose, as the specific case may be. It seems to come up on speed well in the lower end, then just falls short of enough lift to, well, lift at the upper end of the throttle throw.
After checking and re-checking everything I could think of, I was thinking my problem may be lack of battery power.
11-10-2003 Over year old.
 
 
elicopter
Heliman
Location: emerson new jersey

you need to go with the 12 teeth or go with more cells
i don't think 2x6 pith grips are the answere unless you have the rpms to offset the coontrol delay
I may be stating the obvious
if i am forgive me
11-10-2003 Over year old.
 
 
Wright Flyer
Heliman
Location: Finchingfield, England (UK)

Wayne,

Well you could either break the 6 cell 1500 packs and remake them as 10 cell packs though it's questionable whether 1500mAh will have sufficient current sourcing ability as the Corona will want to draw about 20A+ but you do have the advantage that running at higher voltage means less amps needed to deliver the same power (P=IV after all) so may be OK. (1900-3300 are the normal capacity NiCd/NiMh used for Corona)

A better option may be to just use some 3 cell lithium packs but, again, I doubt that those 2100 cells will source the current (it's something like 12C you'll need!) so you may need to parallel them up to make 3S2P or even 3S3P

I think I saw you on Ezone and this may be a better place to ask about all this stuff as that's where the real Corona experts hang out.

Cliff
11-11-2003 Over year old.
 
 
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e-Lite Machines Corona > mega 16/15/4
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