Pattern wing design

[randy10926 at comcast.net]

thanks john.  lots to think about.

Any comments on your variation?

Randy
> My personal observations:
> You may well be on thin ice if you duplicate the Prophecy wing with built up
> balsa. The wing is pretty thin to build that way.
> 
> A symmetrical air foil with a 2:1 chord ratio and Leading Edge & Trailing
> Edge imitating the Extra 300 that is strong and stiff will do fine.
> 
> Build the wing with the top flat on the table and the dihedral will be
> close, if not perfect!
> 
> The leading edge sweep provides stability in the roll axis, the trailing
> edge sweep affects stability in push maneuvers.
> 
> The greater wing thickness makes for more drag. It also adds a lot of lift
> which leaves the plane twitchy in wind gusts.
> 
> The tail feathers play a great role in what we ask to fly our maneuvers. Too
> much stab will make snaps next to impossible. So will too much vertical fin.
> 
> Too little fin will leave things unstable in the Yaw axis. It will also make
> for very poor low speed control.
> 
> Sweep back on the leading edges of the tail feather seems to go a long way
> toward both yaw and pitch stability.
> 
> The shape of the fuselage, its center of lateral area, the relationships of
> the thrust line, wing centerline, stab centerline, incidences, thrust
> offsets, and the sums of all of the drags are important too.
> 
> Where the turbulence has an effect is hard to determine other than flight
> testing. It is even harder to fix.
> 
> Some designs are yaw stable in more than one angle to the centerline. The
> Prophecy is not. It has a fixed angle determined by the amount of right
> thrust.
> 
> The Hydeout seems to have at least two lockable yaw points. You can usually
> set the wind correction at one end of the box and it will track well past
> center hands off in a pretty stiff breeze. Some people love it that way and
> some of us just cannot get used to it. A fair number just adapt and it does
> not matter!
> 
> The only way I know to really screw up a KAO's is to build it too heavy.
> They always fly well, even the crooked ones. My experience has been that
> they fly OK in knife edge but the presentation is poor due to the lack
> lateral area. They are mostly hanging on the prop.
> 
> These are my observations and subject to change with more experience. I
> really can't tell as much about flight characteristics when I am at the
> controls as when I am observing other people flying. Sometimes the Masters &
> FAI pilots fix the flaws so well they are not observable. The Intermediate &
> Advanced pilots struggle with immature designs.
> 
> I have been think about another Kaos variation myself.
> John Ferrell
> 6241 Phillippi Rd
> Julian NC 27283
> Phone: (336)685-9606
> johnferrell at earthlink.net
> Dixie Competition Products
> NSRCA 479 AMA 4190  W8CCW
> "My Competition is Not My Enemy"
> 
> 
> ----- Original Message ----- 
> From: <randy10926 at comcast.net>
> To: <discussion at nsrca.org>
> Sent: Thursday, September 04, 2003 7:40 AM
> Subject: Re: Pattern wing design
> 
> 
> > Anyone know what wing the KAOS and Prophecy uses.  I recently got a Kaos
> kit
> > and the plans for a KOAS 90.  Thinking to building a Kaos 90 with Prophecy
> > wings.  I would like to use one of the wing programs to generate a balsa
> built
> > up wing.  For some reason I would like to really build something.
> 
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