Simviation Forum - I have a question about... Wait for it... MOIs!!!!

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I have a question about... Wait for it... MOIs!!!! (Read 357 times)

Apr 30^th, 2007 at 9:48pm

^Peregrine^ Offline
1st Lieutenant
I Fly Sim!
United States

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Posts: 2

So I've read that Roskam's Method can be used to estimate MOIs for my MSFS2004 plane. Not a problem, I've used three different planes in Roskam's list for each of my plane's axes.

However.... here's the dupe....................

Roskam's Method includes 3 formulas that make use of the maximum takeoff weight, and 3 constants from Roskam's table which assume the aircraft are fully fueled.

The Weight and Balance table in FSEdit uses empty weight, though. Does this mean Roskam's Method can or can't be relied upon, since fuel in the wings contributes considerably to roll MOI?

PLEASE HELP!

Cool

Later....

"When there are two Huns above you and your immediate vicinity is full of lead, well, my boy, it's time to go home. Never mind trying to shoot down any of them . . . try again tomorrow."&&- Elliot Springs, 1918

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Reply #1 - May 2^nd, 2007 at 7:52am

microlight Offline
Colonel
It's a bird...
Southern UK

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Hi Peregrine - welcome.

MOIs - now there's an interesting topic. Sure enough, the FS9 SDK gives a formula for all three MOI variants, but does it based on empty weight. Even so, it's stated to be a rough guide only, and from my own experience these calculations tend to be a starting point, not a baked cake. It's a little like pottery - you need to do it a few times to get a feel of the clay and then work some art into it!

Wink

BAe ATP for FS9 now available! www.enigmasim.com

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Reply #2 - May 2^nd, 2007 at 6:41pm

^Peregrine^ Offline
1st Lieutenant
I Fly Sim!
United States

Gender:
Posts: 2

Hey Microlight,

Thanks for the advice. I'll double check the FS9 SDK for those MOI equations you mentioned. I already got a good piece of advice from another site's forum: estimate size and location of fuel tanks and other 'non-empty' weights, and subtract their MOI's from the Roskam estimate. I'll give that a try, too.

Catch ya later!

Smiley

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