Wind Tunnel Testing Ted's Stealth
In September of 2017, Ted brought his Stealth to the Salt Flats for the first time. His car was inspected by Rex Svoboda and Tom Burkland. Both Rex and Tom are experienced Salt Flat racers and over the next couple of years were very helpful to Ted in regard to improving the car's performance.
Tom commented to Ted in 2017 that the car was well designed and should be capable of speeds over 200 mph. He suggested Ted consider taking the car to Layne Christensen's Darko Wind Tunnel in Ogden, Utah for three main reasons: maximizing safety and handling at speeds over 200 mph, confirming and/or checking out the value of streamlining Ted had already put in place, and discovering "tweeks" to the car's configuration that would result in a reduction of drag and in effect give him "free additional horsepower". Tom said, "... when driving at high speed, It's all about the air!".
So on April 11, 2018 Barbara and Ted took their Stealth to Darko for testing by Tom and Layne.
The car was carefully positioned in the tunnel and placed on sensors which relayed all important data to a computer in the control room which computed such things as changes in drag, front and rear down force and lift, amount of HP required to move the car through the air, etc.
Note: there is nothing worse than a car with too much lift on the front end at over 200 mph ... and then as a result goes airborne!
A number of wind tunnel runs were made to check out the streamlining Ted had put in place,
The data from the first run was used as a base line, Subsequent runs included such adjustments as maximizing the height of the vehicle, best angle of attack (the rake of the car), checking out a 3/4 in. "Gurney flap" Ted had installed, and using cardboard to mock up possible body "tweaks" to reduce drag, etc, See Sample Run #5 testing extending the air scoop all the way to the window. Other test runs included such things as modifying wheel well openings and covering the front wheel wheel openings which is allowed in this class.
SAMPLE RUN #5 - EXTENDING SCOOP TO WINDSHIELD
AFTER WIND TUNNEL TESTING: Here are a few of the "bottom line" Results.
The car's center of gravity (CG) and center of pressure (CP) all maximized for this 98" wheel base vehicle. Ted's positioning of weight distribution front to rear and side to side excellent for Bonneville racing and stability. The CG must be ahead of the CP in order for the vehicle to be stable at high speeds. Ted's car has the Center of Gravity nicely ahead of the Center of Pressure (approx. 16 in.). Weight Distribution: LF=1094 lbs. RF=1073 lbs; LR = 911 lbs, RR = 918 lbs. Total weight with Driver in place, 3993 lbs; Front 2167 lbs or 57.2 %, Rear 1828 or 45.7%. Result based on wind tunnel testing: do not change weight distribution -- vehicle should handle well over 200 mph.
Extending the rear of the engine air scoop to within 2" of the windshield (2" is minimum allowed by class rules) along with covering the air intake at the base of the windshield significantly reduced drag. The equivalent horsepower (HP) gain due to drag reduction on the scoop was over 75 HP. Result: The air scoop has been extended and the space between the rear of the hood and the windshield has also been filled and smoothed.
Car was tested with Ted's 3/4 in. Gurney Flap in place along the trailing edge of the rear spoiler. and then tested without the "flap". With the "flap" in place, down force on the rear end was increased with only a very small increase in drag and turbulence at the rear of the car. Frontal lift virtually unchanged. Result: keep the Gurney Flap and benefit from increased down-force on the driving wheels!
A series of wind tunnel runs were made to determine the best angle of approach (rake) for the car in order to balance lift and down force so as to reduce drag and insure the car would stay stable at speeds over 200-250 mph, i.e. "hug the salt". The results of these runs indicated that the benefits were optimized by lowering the car in the rear beyond where Ted had set the height by 1 1/2 inches, and lowering the front of the car 3/4 inches below Ted's original setting to decrease drag and increase stability at high speeds. Making these changes resulted in a wind tunnel gain due to reduction in drag of approximately 40 HP. Result: Ted lowered the Stealth per the wind tunnel recommendations. He also enlarged/increased the size of the wheel tub area significantly, front and rear, to provide additional clearance to avoid any chance of having the tires rub against the now lowered body at speed.
BOTTOM LINE: Due to the wind tunnel testing, Ted was able to confirm that the streamlining he had made to the vehicle: front, side, full belly pan and rear, had significantly reduced the Coefficient of Drag of the stock vehicle (which was a relatively low 3.3) to 2.0. Over 100 "Free Horsepower" was gained. Wind tunnel testing also suggested the modifications to the body that would reduce drag significantly and would also increase stability at speeds over 200 mph. Ted has made all the improvements. He says that at 200 mph, "... the car runs straight as an arrow and handles beautifully! The car feels like the faster it goes, the more stable it becomes ... it's all about the air!".
Layne Christensen, designer, builder and owner of Darko Technologies explains the benefit of wind tunnel testing.
In this short video he uses the Royal Purple 400+ mph streamliner as an example.
TED'S 825+ HP 434 CU IN CHEVY ENGINE IN A WIND TUNNEL TESTED DODGE STEALTH IS READY FOR YOU TO SAFELY SET SOME LAND SPEED RECORDS!
IF YOU ARE SERIOUS ABOUT LEARNING MORE ABOUT HIS "STEALTH" RACE CAR ... AND POSSIBLY MAKING TED A REASONABLE OFFER FOR IT ...
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