Quote:
Originally Posted by freebeard
What are your thoughts on the plus/minus you found with the reflex tail on Babby Template at Darko?
|
*Since I was trying to reflect a 'real',DOT-friendly,street-legal body,intentionally mutilated to allow for wide-spaced tail lamps and license plate,I knew, going into the project, that I'd have to settle for whatever turned up.
*During the smoke-flow session,even though she was at sub-critical Reynolds number,she exhibited zero reverse flow,indicating a robust turbulent boundary layer for the entire length of the aft-body,with fully-attached flow.That couldn't have been better!
*I'm not comfortable at all with the DARKO lift measurements due to how Baby's ground-board was attached to only a single set of load cell uprights.Since Spirit does not produce lift,I'm confident,that properly measured,Baby won't generate lift as well.Technically,it's impossible for a streamline half-body to produce lift,as long as angle-of-attack is not introduced.The dynamic pressure on the nose,along with the high pressure over the tail,cancels any lift-due-to camber (Bernoulli-effect).They sit at the bottom of the drag 'bucket',with minimum drag,and zero lift.
*Since she came in at an averaged Cd 0.1209,when the actual frontal area was introduced into the raw data,I can't really ask for better.Had she had more plan-taper,and come to a knife-edge,as Cambridge University's Eco Racer (CUER),we'd probably have seen Cd 0.11 or better.
*Enlarged to match the frontal area of,and replacing the body, of a 1994 Honda Accord,the Honda would see an MPG increase on the highway,from 32,to 100 simply by changing the shape.You can read this right off Honda R&D's test data, published by the Japanese Society of Automotive Engineers.
*I suspect,that over time,as artificial intelligence improves,and CFD is further refined,we may discover a few new tweaks for car bodies;but in the meantime,the evidence suggests that we can take Jaray's 1922 aero technology and produce 100-mpg I.C.E vehicles left and right.EVs will do even better,since they've got the equivalent of an adiabatic engine,getting 3X the mpg of the typical ICE car,on a Btu basis.
*Personally,I couldn't be more pleased with the Baby project.I didn't invent a single thing.All I had to do,was do the 'monkey see,monkey do' routine.Mike Turner's one of the few people smart enough to connect all the dots,and just mimic what aerodynamic devotees have advocated for nearly a hundred years now.