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Weight and balance


11 posts in this topic

Posted

Anybody have a weight and balance for a avid mk4 heavy hauler with a 582.  trying to work out some things before I get to far along.

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Posted

99.9 %.... within an inch of the forward CG.

 

:BC:

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Posted (edited)

Not sure what you gain from someone else's WB.  Unless their plane is identical to yours, it wouldn't apply to your plane.  Generaly speaking, most Avids with a 2 stroke engine are on the nose heavy side of the envelope.  Heavier engines make this worse.  Putting battery further back and such help to avoid adding extra weight to the tail.  If you just want the form. I can scan one of mine and get it to you,   Jim Chuk 

 

PS  if you have the builder's manual, Section VIII-D chapter 8 walks you through doing the WB

Edited by Jim Chuk

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Posted

I understand that each one is different. What I am specifically looking for is the effect of placing a fuel tank behind the seat. Am getting very tired of the fiberglass fuel tank discussions. Can have aluminum fuel tank made by a airplane machinist friend of mine very in expensively but am somewhat concerned about 150 lbs behind the seat.

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Posted

If you put 150# behind the seat, you can bet that the bugger will not be nose heavy, but she is gonna be tail heavy, not to mention the constant change in CG as you burn the gas off.  If you are that worried about it, just have him make a tank that will drop into your fiberglass tanks.  Cut the top out of the tank, slip the new one in, screw a lid back on like a cub.  This will keep the fiberglass tank as a structural member of the wing, yet eliminate the other issues that both the fiberglass and the aluminum tanks had/have.

 

:BC:

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Posted

Just did some quick calculations, and looked at my WB.  It showed empty plane weighs 584, moment was 7071.5 for a CG of 12.10"  I used 415 lbs. for people at 16" back and 150 lbs. fuel at 33" back.  (I measured my fuselage, and the back of the seat tubing is 30" behind the leading edge of the wing so guessed at a tank of 6" thick front to back).  I end up with a CG of 16.24 with those numbers and total weight of 1149 lbs..  One problem, is you will have issues folding the wings with a tank behind the seat as well as fitting it in there and filling it with fuel.  Hope this helps.  Jim

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Posted

Leni,  you keep beating me by 2 minutes with your replys!  We are both typing at the same time, but you're faster....   LOL  Jim

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Posted

Thanks, that gives me some hard# to play with.

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Posted

Here is my weight and balance sheet.  This will help.

 

Weight And Balance.pdf

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Posted

Jim,

 

Thats only when the :shitfan:  aint hitting the fan and I can do some surfing on the site.  :lol:

 

:BC:

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Posted

I am working on an avid heavy hauler trigear. rebuilding and am ready for the weight and balance . using the numbers and formulas I have a empty cg at 12.inches and a loaded cg at 13. anybody else have a trigear . my next move is to jack the plane at the cg indicated and see how close it is.

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