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> Mark Drela's SuperGee DLG
[Courtesy of Mark Drela, drela "at" mit.edu, October 2003 - web presentation
by Tomer Jackman, jackman_tomer "at"
EMC.com]
Construction notes are included
in the drawings, which you can download as Acrobat v6 PDF documents in the
links below. If you need a copy of the Adobe Acrobat Reader, you can download
it free from http://www.adobe.com/products/acrobat/readstep.html.
See the SuperGee II !!! Many new photos!!
Introduction
For some of you, Mark Drela
needs no introduction... For the others, Mark has held indoor HLG records
and innovated in many aspects of HLG design for the indoor crowd. He is a well
known aerodynamicist at the Massachusetts Institute of Technology, and who has
won the world wide recognition for his DLG design in the soaring community.
The Supergee
The SuperGee, a descendent of
the family that started with the Apogee, then later on turned into the Allegro,
is a high performance Discus Launch Glider (also referred to “Side Arm Launch”
– SAL gliders). Following this design came the Aegea 2M and Aegea 3M
sailplanes. Some of the features that make this design so unique are Mark’s
specifically design airfoils, full span aileron wings, and a careful attention
to the discus motion forces that effect the launch characteristics.
Mark launching the SuperGee
Drawings and Construction Notes
The SuperGee is designed for 60”
(1.5m) competition tasks. It uses a set of custom-designed airfoils, tuned for
the airframe design parameters. Detailed construction notes and target
weights are provided in the plans - please pay close attention to these if you
wish your SuperGee to have the strength it needs, and the performance it should
have!
SuperGee Construction
SuperGee
plan (Acrobat PDF)
SuperGee
fuselage details (Acrobat PDF)
SuperGee tail
shaping data and diagram (Acrobat PDF)
SuperGee
spar slot details (Acrobat PDF)
Pod
Molding details (Acrobat PDF)
Accurate
tip sanding (Acrobat PDF)
Airfoil Coordinates and Polars
Related Construction Notes
The Wing
Thin airfoils and a long wide aileron on each
wing give this wing it’s three main features:
Reflex – Setting the ailerons up will allow a thinner wing for launch purposes,
Under Camber – Restoring the “normal” position or cambering the bottom yields a
wide range of speeds for the carefully designed airfoil,
Flaps – Generates enough drag to slow the plane for catching or spot landing.
The carbon fiber spars and Kevlar skins provide a strong frame that can take
hard launches.
Tail Boom
As innocent as it may look, the boom has
‘an important role in avoiding the roll’: As stiff as the boom may be, it
cannot prevent all of the launch moments from bending it. As a result, the tail
surfaces will deflect, causing the plane to roll. However, Mark’s design
suggests running the pushrod wires on the side of the boom, opposite the launch
peg. Together with the elevator control horn being on the bottom and the rudder
control horn being on the side opposite the launch peg, the surfaces deflect
in the opposite direction, compensating for the launch moments, and
launching the plane straight. Without this design tweak, launch presets will
have had to be put into the transmitter.
Fuselage Pod
Important! The pod is carefully designed
to accommodate the radio gear and battery. Any Ballast shuld be added
externally (see below). It retains a streamline shape for reduced drag.
Ballast
The location of the ballast is between the
wing and the boom, seated on the two wing pylons. See plan for details.
Tail Surfaces
The elevator is mounted on it’s own pylon
rather than an all-moving surface, so it can take the launch forces, A down
facing airfoil stabilizes the pitch moment, and the control horn holds the
pushrod in place against the boom, saving the weight of a retention mechanism.
The rudder also has a side facing non-symmetrical airfoil for launching.
Best of luck, and please
let us know how you're doing with your SuperGee !
Document Version History
October 26, 2003 - TJ
- Initial
