HISTORY
Development of the Dragon has been ongoing for fifty years in several phases.
Although Rich was unaware of it, historical records show that Trajan Vuia made the first car-plane.
Some might say that he did not intend to drive it on the roads, but it did take off autonomously,
unlike the Wright Flyer and others that required catapults. *Vuia.
The Road Runner
During the author-inventor's pilot training, he envisioned a better lightplane,
called the "Road Runner", that featured:
- wings swinging back over the
body;
- a ducted fan based on the
Stipa "barrel plane", as reported in NACA TR 292,
to eliminate engine and propeller torque effects, reduce the risk of injury, and
eliminate the need for propeller pitch control; - four-wheel landing gear to
improve ground handling;
- simplified flight controls
with full-span flaps integrated with elevator trim; and
- spoiler ailerons to
eliminate the need for rudder control.
RASer
The RASer (inventor's initials), was designed originally in the late '50s as a
lifting-body aircar (
RASer and other roadable airplanes, originally called *Autoplanes; by
the
no parts need be detached at any phase of operation. This criteria then
required that the wings be small enough to be included with the road vehicle.
Previous aircars, such as the Ford/Stout Skycar, the Waterman Aerobile, the
thereby increased the required time for a conversion operation.
RASer was a lifting body design based on reports that some cars lifted several hundred pounds
while travelling at high speeds. While this may seem to be a good thing, the dynamics make
for a lot of induced drag, which is why modern cars have spoilers to reduce this drag.
While this is virtually ignored and/or minimized in most airplane designs,
it is the heart of StrongMobile designs that get a significant lift from the body and so
decrease the wing lift requirement and size in flight, but not on the road.
Jack Northrop, of flying wing fame, is noted for saying that every part of an airplane
must lift, so it follows that a flying car's body must do so.
Vincent Burnelli exploited the concept with his airplanes at *Burnelli
An interesting piece of history was found:
"After the competition in 1939, Burnelli was invited to the US White House to witness the signing of the UB-14B procurement contract by President Roosevelt. In idle chatter, prior to the signing, Roosevelt asked Burnelli who his major financial backers included. Burnelli replied... " A fellow Texan, Arthur Pew." This name sent Roosevelt ballistic. He refused to sign the contracts, threw his pen across the room and ejected Burnelli from the White House. Not only was Burnelli humiliated, for reasons unknown to him at the time, but Roosevelt also directed the Army to issue a new report denigrating the Arnold report. What made Roosevelt go "postal"?
Arthur Pew was on the board of SUN Oil in Texas and was the major financial backer of Republican Wendell Wilkie, Roosevelt's opposition. But was this enough to make Roosevelt go crazy?"
If you search further, you'll see that Burnelli's B-1000 design was similar to Norhrop's
B-35 flying wing, except that the B-1000 has a tail and the B-35 was unstable.
Ironically, aviation lore tells that politicians wanted Northrop to license Flying Wing
production to a plant in Fort Worth; when Northrop refused, all Flying Wings were scrapped.
NASA's Dale Reed did some research on the lifting body concept with the *lifting bodies
You can see how the Strongmobile's rear end or trailing edge is shaped to provide a lifting effect.
The initial single-fin design was modified to the pi-tail to provide a broader trailing edge and more lift.
The second major feature, following from the lifting body, is the quadricycle landing gear and road suspension.
The core design was based on a conventional automobile chassis and suspension,
with large wing flaps, similar to the Boeing B-52 arrangement.
This feature is tied directly to the use of wing flaps that provide lift while the body is level
and so allows the center of mass to be midway between the front and rear wheels and then
allows the wing to be placed likewise, then allowing the wings to be swung into the body.
The *Henri Coanda 1910 was the first thermojet airplane, using a compressor and two
burners mounted on the sides. It burned too much and the first take-off was a
*crash
[Note that the report mentions that Coanda and Caproni corresponded.]
The Stipa "barrel plane with ducted fan propulsion solved propeller stowage.
The inventor was inspired by Stipa, but thought that the extended ductwork was unnecessary
and so preferred using a split duct with side outlets to simplify and lighten the design.
Available information shows that the afterburner system was relatively ineffective.
Technical data is at *CC2
The Curtiss-Wright Aircar was a hovercraft that has side exhausts.
The Nash Airflyte automobile design inspired the covered front wheels.
NASA developed some vectored jet experimental aircraft and flight-tested them.
The aircraft was unstable and crashed.
The inventor was inspired about vectored slipstream lift while doing full-power engine checks
on a 3,000 h.p. A-1 attack airplanes and noticing how the propwash blew onto the wings and
created enough lift to make the airplane rise up on the wheel struts.
The vectored slipstream seemed to fit with the split duct.
The vectored fan-stream design was later seen to be too risky due to the
potential for engine failure at low altitude, such as landing or take-off, and
subsequent catastrophic loss of lift with little potential for recovery.
Originally, the engine purchased was a
It was similar to that used in the Tucker "Torpedo"; it was the key to that
car's performance. The manufacturer no longer supports that engine;
however,their O-335 may be used. A concern is that the road mode operation
calls for extended periods of idling that may foul the spark plugs.
Construction on a prototype RASer was begun, but abandoned due to extensive
relocations and time constraints.
The prototype landing gear mounting was found to be unsuitable due to weakness and
the design had inadequate aircraft brakes and wheels and springs for highway use.
StrongMobile
The RASer was then modified In 1963, when the inventor was an undergraduate
Aeronautical Engineering student, his Airplane Preliminary DesignInstructor was the late
Edgar Lesher, who held world speed records for lightplanes; he advised the class to
"distort the specifications".
The specification chosen by Rich to be distorted came from his
background in Detroit, that is, to distort by increasing the production
numbers by making the airplane roadable. Rich dusted off the RASer project and
modified the design with conventional swing wings as his project.
The underlying theme of the project is to bring flying to more people,
as illustrated by the Spirit of Detroit.
The figure below shows the preliminary design sketch for the project.
The design was to have had a road drive via a power take-off from the
aircraft engine with a Dodge Flexidyne transmission and lightweight,
light duty differential gear by V-Plex.
At full power for take-off, the jet exhaust was calculated to be about 250
m.p.h.,
giving a boost to the wingroot lift, thus retaining the RASer's vectored lift
notion.
A small model of the StrongMobile
was built and displayed at the
Experimental Aircraft Association's National Convention in 1965.
The StrongMobile design was tested in the CalTech Guggenheim wind tunnel
as shown above. The tests showed that the aft fuselage-body and tailplane
interfered with each other and created a nozzle effect; this was cured by
re-designing the aft fuselage to provide more up-sweep towards the tail;
this also makes for a more stable reflexed fuselage airfoil.
The main result was that the lifting body design was valid, that is, the body did provide lift.
Improvements to the 1/12th scale wind tunnel model were mainly removing the
wheels and smoothing over the wheel wells, similar to the retractable concept.
The Cal Tech technicians also removed the wheels and filled in the wheel wells
with clay and tested again; with the streamlining, the lift/drag ratio was 8:1,
which is quite acceptable by airplane standards.
The model had a simulation of an engine cooling exhaust augmenter nozzle;
this cowling design showed separation and was changed.
Other improvements increase the L/D, such as eliminating the engine cooling
exhaust duct drag, increasing wingspan, and re-contouring the turtleback to
reduce interference with the tailplane with a concave curve and replacing
the single dorsal fin with the pi-tail to increase body lift, and designing the
retractable road wheel system.
The design was patented with US Patent 3,612,440,
The design was documented in the first *Strongmobile Development Report.
The design was then put on the back burner, so to speak, as a result of
the vanishing lightplane market that was influenced by liability litigation
and the fuel crunch. The inventor continued to refine the design with
improvements to reduce restrictions, such as weight. The rear end was changed to include a
convertable bumper fairing that provided a degree of crashworthiness.
The large single dorsal fin was replaced with dual fins, a "pi"-tail.
The biggest change was to enlarge the wing surface area to accommodate
the added weight of changing the design to use automotive suspension
and drive train. The solution was to add folding wingtips and stow them.
The wing flip-tips further reduce the induced drag and improve the design.
The design was re-named "Magic Dragon".
(Not to be confused with the 8-passenger, deHavailand/Hawker/Beech DH125 "Jet Dragon").
After 2001, the inventor built two more models of the Magic Dragon design.
A 1/12th scale tether model showed that the stability and
center of mass were OK.
A ½ scale model was built and displayed at the
It had a fixed tailplane, but was otherwise representative of the
Magic Dragon design.
After a barn was built to shelter construction, the full-scale mock-up
was built.
Its design incorporated the folding tailplane concept for better stability.
A great deal of time was spent on studying an electric hybrid version; however,
inputs from folks attending forums and exhibits overwhelmingly favored using
a conventional mechanical road drive, so the design was changed accordingly.
Also, there were objections to using the fan while driving, so a clutch was
conceived for disconnecting the fan.
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