Nsp Mystic

[John McCloskey]

Just ordered a Mystic from Sal. Anyone else out there fly one ???
AND a ????? for OLLIE.
I have a Viking that I got for the wife . It's scratch built from the RCM plans . I need a decent CG .
The center panels are 28.5"long with a chord of 11.5 the outer panels are 29.5" long tapering from 11.5" to 7" at the tip . It's the MK 1 Viking with a flat bottom airfoil,not the one with the Phillips entry. Thanks John

[Ollie]

How far back you can safely put the CG depends mainly on the tail volume coefficient. To calculate that I need the tail moment arm length (25%of the wing chord to 25% of the stab chord) and the horizontal tail area in addition to the wing dimensions you have already given us.

See:
http://www.polecataero.com/
and go to the CG article by Dr. Mark Drela. There is no better information than this on the subject.

[R. Carver]

John, did you build the Viking or did you buy it built? I'm in the process of scratch building one myself (for the past year or so :) ).
As far as the C.G. goes, that stab is so big you could probably put it halfway down the fuse! Just kidding, don't try that... I'll take a look at the plans when I get home and let you know what it says.

Rusty

[R. Carver]

John, the plans show a C.G. of 3.5" from the L.E.

[John McCloskey]

Ollie , Thanks for the response , but it looks like I got my answer !

Rusty, I bought it already done . It is from the RCM plans .
Must have about 8 oz or better in the nose ! This winter ,I'm going to take the covering off the fuse and see where this guy put all the weight :) I got a realgood look at the wings..... For some reason this fella likes washout (1/2" at the tip ) seems a bit much to say the least :) What the heck.... gives me something to tinker with ! Thanks a bunch , John

[Ollie]

The Viking airfoil goes very draggy at angles of attack less than 3 degrees. Therefore, 1/2 inch of wash out (4 degrees) is all right because the plane won't have much of a glide anyway when the tip goes through zero lift. The Viking airfoil has serious stall hysterisis at reynolds numbers less than 100,000 so tip stall avoidance is important.