Fuel cell location? On the thrust line?

[Paul Taylor]

Ok I’m building a Pathfinder and going electric. I want to recess the
Battery compartment into the fuselage. Should I put it in between the motor mount cut out or lower it down on the thrust line?


Sent from my iPhone using Tapatalk

[Ken Culbertson]

Here are two examples of with the battery on the thrust line.  I make the cavity larger than the battery by 1/4" top/bottom and at least 1" on the front/end.  That lets me position the battery to fine tune the CG.  The Pathfinder is Crist Rigotti's, and the Trifecta is my design.  These are old pictures.  I use the foldback Velcro strips like Crist now.  I put my battery on the outboard side to slightly lessen tip weight, but it can go on either side.

Ken

[Paul Taylor]

Here are two examples of with the battery on the thrust line.  I make the cavity larger than the battery by 1/4" top/bottom and at least 1" on the front/end.  That lets me position the battery to fine tune the CG.  The Pathfinder is Crist Rigotti's, and the Trifecta is my design.  These are old pictures.  I use the foldback Velcro strips like Crist now.  I put my battery on the outboard side to slightly lessen tip weight, but it can go on either side.

Ken

Thanks Ken
Going to steal your idea. 😎
And Merry Christmas!

[John Rist]

I now place all of my batteries on the inboard side.  I had one on the outboard side come loose and fly out. the airplane crashed on the spot.  Tail heave aircraft don't glide, they just fall.   

[Dennis Toth]

Since the motor is just above the wing center line, with a long/skinny battery I would go with between the mounts to help the vertical CG (off sets the weight of the wing and gear). I like going through the mounts load from the inside with an inboard cover plate held on with magnets ( https://www.kjmagnetics.com). If your pack does not fit between the mounts (like a 5 or 6 cell) then do flat against the outside nose but still inline with the motor to start. If you use the plate mounted to the fuse then straps to hold the pack you can adjust the height (like you would a tank) to fine tune the vertical CG.

Best,  DennisT

[Ken Culbertson]

I now place all of my batteries on the inboard side.  I had one on the outboard side come loose and fly out. the airplane crashed on the spot.  Tail heave aircraft don't glide, they just fall.   

I used to do the same until I found the right kind of strap.  IMHO having that much weight on the inboard side means more tip weight.  I have never had one of these come off.

https://www.ebay.com/itm/404616786894?chn=ps&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=404616786894&targetid=4580909053911843&device=c&mktype=&googleloc=&poi=&campaignid=603247654&mkgroupid=1236951625700523&rlsatarget=pla-4580909053911843&abcId=9316139&merchantid=51291&msclkid=1b6bb345bb841bd9a90dd42d8651f24a

Ken

[John Rist]

I used to do the same until I found the right kind of strap.  IMHO having that much weight on the inboard side means more tip weight.  I have never had one of these come off.

https://www.ebay.com/itm/404616786894?chn=ps&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=404616786894&targetid=4580909053911843&device=c&mktype=&googleloc=&poi=&campaignid=603247654&mkgroupid=1236951625700523&rlsatarget=pla-4580909053911843&abcId=9316139&merchantid=51291&msclkid=1b6bb345bb841bd9a90dd42d8651f24a

Ken

That is the type of straps I used.  In hast, one did not get hooked well enough.  With the batteries recessed into the fuselage and almost at the center line between the wing tips it makes very little difference on wing tip weight.

[Brent Williams]

Roger Kramar's method.  Lightweight and keeps the battery secure.  The velcro isn't doing much heavy lifting. 
Locate the battery anywhere you want with the depth of the aluminum cage, ie, on the centerline or biased outboard.

[jerry v]

In line electric motor, battery and wing.

Jerry

[Ken Culbertson]

Jerry, very interesting motor mount.  Simply converts an IC fuselage into an Electric. You might consider rounding the fuselage at the rear of the mount. 

Ken