stunthanger.com
Electric Stunt => Gettin all AMP'ed up! => Topic started by: FLOYD CARTER on August 20, 2009, 11:00:23 AM
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I want to build an all-out competition stunter. I have a couple small electric C/L models. Now for a big one!
I have:
Hacker A30-10XL
2 ea 7.4V 3200 mah = 14.8V
X-55-SB-PRO controller
Lacking only the Ztron timer
Total power package weight is 21.3 oz
Is this battery sufficient? Would appreciate recommendations for a suitable kit or scratch-build for this combination. The weight is my big concern. I'm thinking any kit would be too heavy, but maybe "bashing" a kit for lighter weight?
Floyd Carter
AMA#796
Eugene, OR
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I want to build an all-out competition stunter. I have a couple small electric C/L models. Now for a big one!
I have:
Hacker A30-10XL
2 ea 7.4V 3200 mah = 14.8V
X-55-SB-PRO controller
Lacking only the Ztron timer
Total power package weight is 21.3 oz
Is this battery sufficient? Would appreciate recommendations for a suitable kit or scratch-build for this combination. The weight is my big concern. I'm thinking any kit would be too heavy, but maybe "bashing" a kit for lighter weight?
Floyd Carter
AMA#796
Eugene, OR
Floyd,
First off how big is "big"?
going on
Hacker A30-10XL Brushless Outrunner RC Motor, 176g, 650W, 900 RPM/Volt
a kV of 900 rpm/volt means you need at least a 4 cell lipo battery. You can get this by hooking up your two 2cell packs in series. That isn't a big deal. I am not that acquainted with the Hacker motor series, but lets assume for a moment that it is (I think it is ok). It weighs 6.2oz which is in a reasonable range of what most of us are using (somewhere between a 20-26 mm length magnet motor in weight).
I am not acquainted with the ESC. The commonly used ESC's are the Castle Creations--but the main thing is that most of us are using an ESC with a governor that keeps the rpm constant.
With respect to the battery, you have the equivalent of a 4s3200 pack, again, in the range of a modern stunter (more than I use, but I think close to packs that Crist Rigotti uses.)
Since the total weight is in the 20oz range, yes you want to build light. I think that might mean choosing "plastic" over paper for covering! ;D
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Floyd,
I'm in the same boat as you. I am finishing up my first dedicated electric build. I designed my own model and tried to copy some of the looks and dimensions from some well known glow stunters. I am attaching a few low quality pictures. My camera is broken so I had to resort to my cell phone...
I have been lurking here for a while trying to pick up what I can and apply it to my own model. The specs of my new model are:
wingspan: 53"
wingarea: 575 sq"
weight: right now it is 42 ounces(only needs a few pieces of trim and painting the wheel pants)
Once I have flown and verified that my power system is functional and appropriate I will post details.
Jason
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Welcome aboard Jason. Nice looking airplane. 575 sq in is the same size as my Resolve EP. Please keep us posted on your progress.
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By "big", I mean that I already have a reduced-size elect. Ringmaster and a tri-motor (2 in front and one in back) motors with about 40" W.S.
Therefore looking for something about 50" to 55" W.S. if that would be the right size for this motor. Maybe a T'Bird clone? Or??
I think simplest is best, to keep weight down. Also thinking of light silkspan and clear dope. No paint.
Floyd
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I think you need something a bit larger than a T-Bird to carry the battery weight--something like Crist's size plane.
You can do the math. Subtract 21oz from the what you think a reasonable weight is for your typical stunter of choice. That gives you an idea of what the airframe weight target is. If you think 50 oz is fine for a T'bird, that means you need to build one at 29 oz. That is doable I think, although I am not sure if a 50oz Tbird is likely to be a good flyer. Maybe you can get some "testimonials" from others.
My Vector is flying right now in the 47-48 oz range. It seems to fly pretty good. I think that it might me slightly smaller than the T'bird, but I am not sure.