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Originally Posted by DaveBirkenstock
I'm not familiar with that book or that project. It makes me wonder what their goal was and what the geometry looked like.
Without a concave structure downstream of the suction inlet, no aerodynamic thrust will be created & if you're going to spend the energy anyway, why not get some thrust as return on that investment?
As for the suction pump, the first flight test was in the 1940s. They proved over a 40% increase in efficiency using a centrifugal compressor as the suction pump. I'm sure current pumps/fans are better.
Are "sucker cars" like the Chaparral 2J and/or Brabham BT46B in that book? I sometimes tell people this works kindof like they did only instead of powered downforce it's powered pressure recovery.
-Dave B
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Dave,the Corvette was a notch-back style roof design and the inlet slot was positioned at the base of the rear (nearly vertical ) backlite.The premise of the research was to see if they could achieve with the notch-back,what otherwise would require a fastback roof,with taper in both plan and elevation.They used an outboard power source for the suction,and in the energy balance,a net loss was demonstrated,although the the car did achieve lower drag.------------------- With respect the Chaparral,that car used a Bombardier two-stroke snow-mobile engine to power the dual high-static-pressure fans for the under-car suction.----------- A side note,is that with Ford's Probe-IV concept car,with rear quarter-panel heat exchangers(radiator and AC condenser),the car achieved 4-mph on level road from the thrust generated by the two electrically-driven cooling fans.Of course,this "thrust" would be lost in the signal-to-noise ratio of the engine's output during normal driving,however it cannot be said that it was not there,at least when the fans were operating.