As it happens my neighbor is an authorized dealer for Genesis and I thought
he might want to comment - so I forwarded the Genesis comments to him and
here is his reply. I hope it is worth the bandwidth to you - surely it's
better than the recent vendor flames... Jim
Jim Monaco
Rocky Mountain Soaring Association
Denver, CO
Jim, this subject came up last November during an
argument about flying wing gliders on
rec.aviation.soaring. Robert Mudd, who was heavily
involved in the Genesis project wrote this article for
the newsgroup.
"A tale of the Genesis tail."
Given the current discussion about flying wings and
other things I thought there might be some interest in
the following.
When I joined Group Genesis in Nov. of 1992 many
things about the basic design had not yet been
decided. One of the questions was should the glider be
a pure flying wing or have a separate elevator.
Naturally, Jim Marske wanted a pure flying wing and
recommended this to the company owner Jerry Mercer.
After thinking about it I recommended a separate
elevator; I reasoned as follows:
1. The center of gravity range of a flying wing is
very small, the pilot sits on or very close to the
center of gravity. This places the pilot's head aft of
the leading edge, much like the seating position of
the Schweizer 1-26. I felt strongly that the pilot
needed to have his head out in front of the wing's
leading edge both for collision avoidance and
navigation
2. We needed to comply with the J.A.R. requirement for
cockpit loads of 154 to 242 pounds (70 to 110 kg).
without the use of compensating ballast. We also had
to deal with the c.g. shift from adding and dumping up
to 400 lbs. of water ballast in the wings. All this
added up to the need for the counter balancing force
that is provided by a separate elevator with some down
force.
3. No one I questioned could assure me that with a
wing loading of 10 lbs. per sq.ft. deflecting the
trailing edge of the wing would not hurt the climb. To
my knowledge nothing like that had been tried in
gliders and I think this may still be the case.
4. I felt the market was not ready for a pure flying
wing. At that time no one was loudly championing
Marske's designs and refining them. Pure flying wings
did not have a wonderful image. In fact even after the
prototype was flying we continued to receive adverse
comments about flying wings, even though the
Genesis is not a pure flying wing. The validity of
those adverse comments is another story altogether.
The ultimate decision was of course Jerry Mercer's, it
was his company and he opted for the separate elevator
configuration. There is a down load on the elevator so
it does have some stablizing effect. The force ammount
depends on the location of the c.g. the numbers escape
my memory so I can't provide any details.
The placement of the elevator also had some
interesting features. John Roncz, our computer
aerodynamisist, wanted it on a boom well aft of the
vertical fin. This he said would cause the least
amount of drag. Jim and I made some sketches of the
drive mechanism and voted it down. The present system
took a lot of reinforcing of the fin but has proved to
be quite strong. The separate elevator allowed us to
tailor the pitch stability by varying the weight of
the push rod in the fin. The glider could be made to
go from very stable, statically and dynamically, to
mild dynamic instability.
Every machine including flying machines is a
compromise. Every designer and engineer hopes they
choose the most favorable, least harmful compromises.
Sometimes they combine in a favorable way and
sometimes they do not. It all costs money and very few
projects are blessed with an unlimited budget, there
are always some restraints. If there were ever a
follow on project to the Genesis some of its design
features would be kept and some would be changed.
But for now Genesis owners continue to work on
improvements to their gliders just as owners of other
types do.
Robert Mudd
Genesis 2
sn 2009
) 1998-2001 Glider Pilot Network
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 10, 2002 9:20 AM
To: [EMAIL PROTECTED]
Subject: RE: [RCSE] Production Runs
The stab that was added is a full flying "trim tab" and supposedly not used
for stability. It is supposed to trim the airplane for maximum performance
at different speeds, which can be a problem with plank style wings.
Performance of the Genesis 2 is very good compared to other airplanes in
its class, but perception is still somewhat against it.
Kristopher
> The Genesis full sale Flying wing was originally designed without a
> horozontal stabilizer and flew fine. In order to go into production it
> was neccessary to add a small stab, don't know if it was FAA or public
> perception, or both that caused the change.
> John Derstine
>
> Endless Mountain Models
> [EMAIL PROTECTED]
> http://www.scalesoaring.net/EMM/rand.htm
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