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Spaaro
Aug 22, 2003, 01:34 AM
Good evening all,

I have a design question that may be in the 'search' library but time is of the essence
and I know someone always has the skinny on aerodynamics here.

I am getting my signif other's 10yr old son into models & planes(he's even talking about
joining the Navy now too). While he's satisfied with practicing the basic principles off
of chuck gliders, he has a voracious appetite for military history and has been sponging
up all the books & mags I've got available. I've never seen a PlayStation-era kid w/out
father/male-military family role model present, who has such an interest in WWII & VietNam.

I told him to look through my modelling mags and pick 1 out of 4 planes he would like to
try building(excluding jets,helis & complex jobs---beyond my skills ;-o). Whether it would work
or not will be our shared experience.

He picked 2 similar sailplane designs that there wsn't a name for(not kits) and had a
resemblance to birds. I've been drawing an exciting hybrid of the 2 with the features that
he liked and some ad lib.

An unusual feature is an anhydral swept stabilizer and forward position verticle fin, a little
like a Harrier but with the fin/rudder along the tail length. Kinda looks like the rear of a
dolphin, including the dorsal fin but with its tail fins not so far back and angled down.

The fuse from wings forward is conventional. Would i encounter any unusual flight
characteristics from this layout?

When time permits i'll make a chuck glider. My own models are on serious back burner ;-(

Spaaro

Ollie
Aug 22, 2003, 05:02 AM
The effectiveness of the tail surfaces for stability and control depend mainly on their distance from the wings aerodynamic center (tail moment arm length) and their area. For the horizontal tail these factors are in comparison to the wing chord and wing area. For the vertical tail these factors are in comparison to wing area and wing span. The bigger the tail area with respect to the wing area and the longer the tail moment arm with respect to the wing chord (for the horizontal) and the wing span (for the vertical) the more stability and control power. The effectiveness is expressed numerically by the tail volume coefficients. If you want to know the algebraic formulas for the tail volume coefficients, just ask.

Spaaro
Aug 23, 2003, 04:14 AM
Time delayed PC access again!

Belated thank you. What i needed/wanted to hear.