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Subject:Re: Osoba and dynamic soaring...
From:Stan Fisher
Date:Wed Sep 06 07:00:05 2000

I dont have an email address for Joe Wurtz, but maybe someone out there can
hook you two up. Joe is a fellow Cal Poly Aero and a really smart guy.
Back in school he could do things with his R/C sailplane that were just

Stan Fisher

"Cameron" wrote in message
> I will put on my flame retardant suite before I say this... One my many
> other passions is radio controlled soaring. A very well known R/C
> pilot (and previous world champion), by the name of Joe Wurts, has
> successfully been experimenting with dynamic soaring for some time now.
> has managed to fly a R/C glider using dynamic soaring for EXTENDED periods
> of time. For more information, see the email archive list at the
> links:
> Thank you.
> Cameron
> "Al Bowers" wrote in message
> >
> > I had the great fortune to listen to Gary Osoba talk at the Western
> > Homebuilders Workshop this weekend about his latest work on dynamic
> > soaring. I may be overstating the case, but I believe Gary (and Taras
> > Kiceniuk Jr) are onto something, perhaps as fundamentally challenging
> > as Paul MacCreadys original speed ring idea.
> >
> > While the decription sounds like the "dolphin flying" which were
> > accustomed to, it is different for some radically different reasons.
> > Gary and Taras think that it is necessary to fly at very high speeds,
> > which rotates the lift vector very far forward. Drag is also rather
> > large, so the resultant of lift and drag opposes gravity. But when a
> > small vertical component of airt is encountered, the effect is to
> > rotate the lift vector further forward. At this time, Gary performs a
> > very strong pull, increasing G on the airframe to about 2. As soon as
> > the following sink is encountered, Gary perfoms a push to 0 G. the
> > theory from Taras says that sink should be countered with negative G,
> > but Gary feels that an error in timing would destroy any gains he has
> > made, while 0 G imposes no induced drag penalty (or minimizes the
> > total drag penalty is probably a better way to put that). Gary is
> > using this technique on the old Sigma open class variable geometry
> > sailplane that was modified by Professor Marsden.
> >
> > Gary showed some data taken with an integrated GPS/barograph unit. In
> > the first segment, he flew at something over 120 mph, using his 2G
> > pull and 0G push technique. At the end of a 12 mile segment, he had
> > lost 1000 ft of altitude. So he stopped and thermalled up (as Gary
> > puts it, "thermalling is a waste of time"). Gary felt that perhaps he
> > had not rotated the lift vector far enough forward, so in the second
> > segment, he pushed his speed up to 183 mph. In this 16 mile run, he
> > GAINED altitude. But the maneuvering is VERY dynamic, the push/pulls
> > are coming every 14.4 seconds with altitude variations of 1000+ ft
> > everytime. Gary described the lift that day as very normal, with no
> > streeting or organization. The data was astounding.
> >
> > Perhaps the old adage (Ive usually heard it credited to George
> > Moffat) of "fly straight ahead and climb" should be revised to "fly
> > straight a head, push, pull, and climb." If you get a chance to see
> > this talk, please do so.
> >
> > Thinking about it, it requires a coupling of the airmass (total energy
> > vario, but without filtering), the sailplanes polar (at various G
> > levels), and the airspeed. Gary says that the math indicates an
> > optimum G level which rapidly exceeds the ability of the sailplane (or
> > pilot) to perform. But even with "moderate" 2G/0G technique gary is
> > flying seems to work. I could see where an LED light system operated
> > by those instruments and a microprocessor could be made to indicate
> > what G level should be pulled for every flight condition...
> >
> > Al Bowers
> >
> > --
> > Al Bowers
> >

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