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As I get within a week or so of doing weight and balance on my 320, it
seems that somewhere I heard that Lancair had revised the forward limit
on the 320.  My construction manual, from mid 1989, calls for a CG
envelope of  FS 24.5 to FS 30.3 inches.  Is this still valid, or has the
forward limit been revised?

Dick Alden,  N425A in Fort Worth, TX.


[The factory performed extensive flight tests to expand the forward CG
limit from 15% of MAC to 11% of MAC.  They found that the aircraft was very stable and performed nicely with a CG as far forward as 8% of MAC, but
they've chosen to restrict the forward limit to the 11% MAC number for reasons they couldn't get into with me at the time of our conversation.

The aft limit is at 29% MAC, and from these 2 numbers you should be able
to calculate your limits based on whatever datum you choose to use for your
CG calculations.  If the original forward limit was 15% and equalled FS24.5
and the aft limit is 29% equalling FS30.3, then a 5.8" range equals 14% MAC,
or 0.414" / 1% MAC.  Since they've moved the forward limit to 11% MAC the new FS number will be 24.5 - (4 * 0.414) = 24.5 - 1.66 = FS22.84.

There ya go.    <Marv>       ]

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