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The Carbon Dragon is best described as a "foot-launch
able sailplane" although it meets the FAI definition of a hang
glider, and neither glider nor pilot need to be licensed. It can be
launched by foot, auto tow, air tow or bungee. It has superb
climbing ability, and will soar in extremely light conditions. It
soars in lighter conditions than any other soaring aircraft available
today. It has significantly exceeded world record and out-and-back
flights in its class.
Jim Maupin's original concept was a design with a 40 ft. wing
span and a sailcloth flap that would roll up on a roller inside the wing,
changing the area from 100 to 140 square feet and back again. After
the tail boom and horizontal tail were already built, he was still
struggling with the wing design. With the help of his friend and
consultant, aerodynamicist Irv Culver, a new wing was developed with
airfoils by Irv. It has a span of 44 feet. It has 30%
chord, full span flaperons. As flaps, they operated from -5° to
+15°. As ailerons, they have a 4 to 1 differential and operated
from 4° down to 16° up. They are driven by two
vertical push rods operating inside the fuselage... simple!
In flight the pilot is totally enclosed. The cockpit area is
17 inches wide in the area of the pilot's hips. Twelve inches
above this in the shoulder, arm and elbow area, it is 25 inches wide. The
structure consists of two triangular torque boxes down each side. The
landing gear door is hinged on one side. When closed and
latched, it is a 7.5G structure like all the rest. The glider lands
on a wheel on the bottom of the door. The door extends some distance
behind the pilot. If he stumbles and falls forward, his body goes up
inside and the airframe hits the ground -- the pilot does not get a
145 lb. glider on his back.
In construction, the glider is basically a wood fabric
sailplane, with judicious use of carbon for significant weight savings and
to produce adequate stiffness. The wing and tail spar caps are constructed
of carbon. The tail boom is an elliptical carbon tube made in two
halves inside a simple mold. The control torque tubes are carbon
formed over aluminum tubes, after which the aluminum is removed with
swimming pool acid. The flaperons are each 22' long and driven from the
inboard. They are carbon - wood is strong enough, but not stiff
enough to avoid flutter. The rest of the structure is pretty straight
forward. Wing ribs forward of the spar are band sawed from 1/4"
5-ply mahogany. Aft ribs are built up from 5/16" square spruce.
Covering is dacron. The whole glider is designed to 7.5 G's ultimate, and
has been proof loaded to the 5.0 G limit load. Time to build is
approximately 1,500 hours, and a current builder estimtes the cost to be
about $3,000. minus instruments.
All the early flights tests were done in the Tehachapi Valley. Airport altitude is 4,200 feet and density altitude varies up from that depending on temperature. Although the Carbon Dragon has been successsfully launched by the auto tow, aero tow, bungee and foot, however, most of its flights were made by auto tow.
The pilots who have flown it agree that the performance figures are realistic. It loses about 20 feet in a 360 turn. The stall is gentle and straight. The side stick seems totally natural. No one commented on it, though it was the first time many of them had flown with a side stick. Probably this is because time control pressures are very light.