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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Tim Stagg on April 18, 2010, 05:59:46 PM

Title: Battery Location on Profile Model
Post by: Tim Stagg on April 18, 2010, 05:59:46 PM

Anyone,

Does it matter....Rule Book Wise, if the battery is on the inside or outside of the profile?

Reason being, it would make it much easier to fasten the battery, if I did not have to fight centrifugal force.

Also, are there any disadvantages for placing the battery on the inside profile?

Thanks

Tim

Title: Re: Battery Location on Profile Model
Post by: Dennis Adamisin on April 18, 2010, 09:21:03 PM

IK am doing that with every profile I build now - for the reasons you stated.  In fact I am working on in inboard side hatch for a full fuse bird - again for that same reason.

IC profiles have their tanks on either the inboard or outboard side, so why not us?  Some of the batteries can virtually be hidden in the profile fuse too.

Title: Re: Battery Location on Profile Model
Post by: Mike Anderson on April 18, 2010, 09:51:00 PM

Quote from: Tim Stagg on April 18, 2010, 05:59:46 PM

Anyone,

Does it matter....Rule Book Wise, if the battery is on the inside or outside of the profile?

Reason being, it would make it much easier to fasten the battery, if I did not have to fight centrifugal force.

Also, are there any disadvantages for placing the battery on the inside profile?

Thanks

Tim

I built a 'Fancherized' Twister, originally had the battery placed on the inboard side ( 3 cell, 3600 mah).  After completely filling the tip weight box and still needing more, I moved the battery to the outside, emptied the tip weight box except for a little over half an ounce.

I can't think of any other disadvantages off hand - just a weight distribution anomaly.  I generally weigh my wing ribs and get the heavier ones outboard, but I don't remember if I did this or not on this plane.

If you use smaller, lighter batteries, then this might be much less a problem.

Title: Re: Battery Location on Profile Model
Post by: Tim Stagg on April 19, 2010, 08:08:58 AM

Thanks Guys,

This is what I thought, just was looking for some validation and or reasons for not doing it this was way.

Thanks again.

Tim

Title: Re: Battery Location on Profile Model
Post by: John Cralley on April 19, 2010, 08:44:50 AM

Tim,

I have been mounting my batteries under the outboard wing root. I then need little or not tip weight.

John

Title: Re: Battery Location on Profile Model
Post by: Dennis Adamisin on April 20, 2010, 04:16:03 AM

One more factoid I neglected before: I have the battery pocketed, that is a large battery shaped hole cut in the profile fuse so that the battery is nested but also that puts it very near on-center on the fuse, thus avoiding the issue Mike A encountered.

Title: Re: Battery Location on Profile Model
Post by: Mike Anderson on April 20, 2010, 08:12:05 AM

Quote from: Dennis Adamisin on April 20, 2010, 04:16:03 AM

One more factoid I neglected before: I have the battery pocketed, that is a large battery shaped hole cut in the profile fuse so that the battery is nested but also that puts it very near on-center on the fuse, thus avoiding the issue Mike A encountered.

Surprising how much "tip weight" the typical side-mounted glow engine/muffler/fuel tank takes the place of, also.  With a fairly lightweight, round motor mounted pretty much dead center, the battery placement actually does become a concern in the roll-axis.  I would have thought that this would have been an issue with, for instance, Ted F.'s Imitation or some of the designs with inboard mounted engines also, but I don't remember ever seeing it mentioned before.

Title: Re: Battery Location on Profile Model
Post by: Dean Pappas on April 20, 2010, 10:49:29 AM

H Gang,
So now the question is: "what combination of battery off-center and tip weight is both statically and dynamically balanced against line weight/inertia?"
Oh fiddlesticks! Probably doesn't matter n~

Dean

Title: Re: Battery Location on Profile Model
Post by: Tim Stagg on April 21, 2010, 02:52:53 PM

I am dealing with a Magician and relativity small 3 cell pack, figure around 2400 mah to do the whole pattern.

I have flown the model for about 3.5 minutes with a 2100 mah which is not enough nose weight, but it flies pretty well with the inboard mounted battery.