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FLYING CARS
J79-3 Afterburner
i- u u. Turbo- jet engine
Cockpit pressurization Fire bottle 1 * Camera
C02 extinguisher \
duct
Multi-channel
balancer Boundary layer
bleed
\
Drag chute
housing
Fuel tank
Main battery
High pressure brake tank
biggest problem is not so much a reduction in drag
but “its the lift which will kill you at these speeds.”
Plans now call for another assault on the sound
Air breathing Instrumentation
barrier at Bonneville but as yet he has no fixed timetable.
system power
With proper testing and good area rule work he can
pick up another 100-150 mph with the same 15,000-lb-
thrust J79 power plant. The vehicle is to be a com
promise between his first Spirit (407.45 mph in 1963),
Trapped air pressure buckled body panels like card and Sonic I.
board, caving in the skin. To alleviate the problem, “A healthy set of brakes may be all we need,” he
panels were punched with louvers, the front fins were says. But when he goes for the 700 mph barrier he’ll
doubled in size and a spoiler was added to keep the nose put his trust in the Goodyear Hemis-Flo drag chute.
down. Says Breedlove: “The problem is to avoid a flat (Sonic I had single-disc, 18-in.-diam double-caliper
bottom, get higher off the ground, and distribute ground brakes, of %-in. forged steel.)
pressure more equally to eliminate the tunneling effect He is thinking of employing an explosive mechanism
underneath.” with two time delays and a cutting blade in the reefing
No positive lift was experienced up to 354 mph, but line. This would chop the line when chute goes out to
a positive pitching moment on rear wheels was noticed, 4-ft-diam at 700 mph, extending it to 8-ft-diam only 4
he reported. Beyond 550 mph the transonic problem seconds later. Deceleration flaps and speed boards might
caused the lift due to the car’s symmetrical nose shape be helpful, and a small Jato thrust reverser could be
and supersonic flow beneath it. Breedlove believes his useful, but might present a retro-stability problem.
and difficult, says Bill Bettes, day is most impressive. They’re produces only longitudinal aero
Director of Caltech’s 10-ft wind already moving at high speed dynamic effects which have no
tunnel. “Most road tests can with a drag rise and possible in effect on the lateral dynamics, if
measure lift and drag forces, crease in lift so the compressi vehicle is operated at constant
pressure distribution and wind bility effects are important con speed. Thus the entire gust re
noise location. But you can’t get siderations in design. Some of sponse is due to the cross wind
steady state forces, rolling or them have already entered tran velocity components.
yawing moments. And you can’t sonic speed ranges where a The researchers believe a full
get much input for lateral sta local flow along certain sections scale road test program is now
bility data.” of the body may exceed Mach 1. indicated using a highly re
Wind tunnel testing, says Roger Hawks, University of sponsive vehicle such as a VW.
Bettes, gives you control over Maryland, and Eugene Larrabee, Such a test would measure the
ambient conditions; control of MIT, report that the influence force of the moment induced on
attitude of model vehicle. And of cross wind disturbances on the vehicle by vertical gradients
you can measure various mo vehicle aerodynamics is ap in the cross wind.
ments data using handy tech preciable. “From wind tunnel At the Los Angeles aerody
niques not useful on the road. test data it appears that the namics meeting it became ap
And most important, in the wind vertical gradients of the cross parent that there’s a general lack
tunnel you can make major con winds play a large role in re of standards for race car design.
figuration changes quickly and sponse of vehicles to gusts.” A This includes both a lack of
evaluate them. gust acting on an auto has two standard testing procedures and
The case for wind tunnel test results, one parallel to the di a common technical language on
ing high speed land vehicles at rection of vehicle motion and one which to base engineer-designer-
the speeds they are attaining to normal. The parallel component driver discussions.
August 1, 1968 25
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