lml@lancaironline.net Mailing List Archive

Ed,

Scott is correct that air pressure will not really assist in closing the door.

That region of the wing is very near ambient pressure or slightly negative in cruise. Being near ambient, the standard gear has never really had an issue keeping the doors closed in flight. Adjusting the bracket should do the trick.

The outback gear is another animal. The larger wheels do not fit the wing cross section and thus required doors with bump-outs....or really upside-down airfoils. These are subject to very strong downward forces.

If you want to dig into some more detail, take a look at page 52 (approx cruise condition) in the following NASA report on our airfoil. You'll see the lower surface with a slightly negative Cp ~-0.2 throughout the middle of the section.

http://www.n91cz.com/Interesting_Technical_Reports/NASA-81-tp1865.pdf

Chris Zavatson

N91CZ

360 std, 1,400 hrs

http://www.n91cz.net/

From: Ed Gray <egraylaw@swbell.net>
To: lml@lancaironline.net
Sent: Friday, January 11, 2013 1:46 PM
Subject: [LML] gear doors

Chris, I have original gear with 3 doors. Haven’t filmed underside of plane in flight, and many thanks for your excellent information. On the jacks, my middle door hangs slightly open (1/4 inch) at trailing edge, but I always assumed high pressure air will push it closed at cruise. What do you think?

Re: cg of 360-mine weighs 1125 empty. It’s almost impossible to load outside the cg. With me (175 lbs. and light fuel, I need a 20 lb toolbag in the back to keep it in the forward CG. I have Superior IO360, long cowl and MT 3 blade.

PS THANK YOU CHRIS ZAVATSON for being a goldmine. You don’t get this service with Beechcraft of Mooney!