Weight and balance "square"

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gme9261236
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Weight and balance "square"

Post by gme9261236 »

I put an app in my phone to quickly compute weight and balance (WnB Pro.)

When I configure the envelope it's actually a perfect square. Just wanted to make sure I am seeing is correct.

The square envelope assumes that the airplane is ok at empty weight all the way up to max gross at both 9" to 15.5" CG.

I know it would be difficult to even hit some of those numbers but is that what you all are seeing as well?


Most aircraft (none I've seen) have a square envelope. Its usually more irregular or half trapezoid like.
gme9261236
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Re: Weight and balance "square"

Post by gme9261236 »

Edit: should say most aircraft DO NOT have a square envelope.
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danerazz
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Re: Weight and balance "square"

Post by danerazz »

As published, yes, it is a square. If you search on here I posted an excel spreadsheet that graphs the wt/bal and it is indeed a square.

Technically, it is up to you to test the "corners" of the envelope, and then adjust the limits if you find some behavior you do not like. That is all part of phase I flight testing.
Dane

Paralysis by analysis
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Twotterdrvr79
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Re: Weight and balance "square"

Post by Twotterdrvr79 »

I can't seem to find the EXCEL spreadsheet that shows the CG envelope you had posted. I built one in foreflight and wanted to compare numbers but, I can't... Can you re-post it? I also wanted to confirm that the W&B will be for the Highlander.
Thanks
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danerazz
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Re: Weight and balance "square"

Post by danerazz »

I have not tried to open the link recently, but here is the post:

http://www.wingsforum.com/viewtopic.php ... bal#p39324

This works better in excel, for formatted text (in and out of range color changes) and actually plots the CG.

There are two worksheets, one for planning and one for line use. SOME of the numbers from sheet one port to sheet two.

Please read the notes in the first sheet for details.

Good luck!
Dane

Paralysis by analysis
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danerazz
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Re: Weight and balance "square"

Post by danerazz »

Just messed with it on my iPhone a bit, it seems to still work in Numbers, just won’t change the text colors but DOES seem to plot CG okay, though not a thorough test...
Dane

Paralysis by analysis
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Twotterdrvr79
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Re: Weight and balance "square"

Post by Twotterdrvr79 »

Thanks Dane. I will do some comparison and see how it ends up. I am new to the Highlander CG figuring and thus far the CG on my aircraft won't let me take more than 50LBS of cargo before ending up to far aft. Looking as though I may have to relocate a few things and add a led spinner to my setup... I suppose, this is a recurring theme? Thank you for adding the spreadsheet.
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danerazz
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Re: Weight and balance "square"

Post by danerazz »

I’m assuming you have a Rotax, and I know several people have moved the battery from aft to a lithium, firewall mounted setup.

Obviously every plane (especially experimental) is unique. If you bought the plane used, I would start by leveling it and weighing it, not that I don’t trust others, but at least you know what you really have. Drop a plumb bob from the leading edge while level and measure all the arms (wheel positions, seats, key points in baggage, etc) and adjust your WT/BAL from that. And if you end up changing anything, remember something simple like moving a battery from aft of baggage to the firewall will make a HUGE change in CG.
Dane

Paralysis by analysis
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