Service Letter 30A

Just finished a build and weight and balance on a Model III and find my most aft CG at 14.7"

This is outside of the 14.28" stated as a max CG in my build manual.

However, I see Service Letter 30A opens up the aft CG to 16".

http://www.kitfoxaircraft.com/Service%20Letters.htm

In the right column of the link it looks like it applies to Models 1 through IV, however reading the actual text in the letter doesnt indicate this (model IV only).

Anyone have better feedback on this (I.e. what is the max AFT CG for the old undercamber wing)?

Larry S.

Another quick question. I have the optional leading edge formers install. This would move the datum forward. I dont see a correction for this shown anyhere.

Anyone know if the datum changes when these formers are installed, or does it cancel out some way?

Larry,
I have been waiting for someone to chime in here that has more experience with the IIIs. I will take a stab at what logic says to me. The service bulletins seem to apply only to the IV only. I see that there is a 30 and a 30A. Internally they indicate that they are IV specific. My guess for W/B consideration, if you used a spreadsheet provided by the factory to calculate W/B it would use the leading edge of the spar as the datum and you would still be slightly aft of the aft most limit. If you measured from the new leading edge and built your own spreadsheet, I would think that your new forward arms being shorter and your aft arms being longer you would be well within the factory limits. I have a piece of un-mounted leading edge and my measurements show that with the leading edge attached, the leading edge moved forward .526 inches.

Thanks Lowell.