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Old 06-20-2018, 06:12 PM   #740 (permalink)
aerohead
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Quote:
Originally Posted by freebeard View Post
So in extreme cross-wind conditions, which has the advantage:
  • Template stinger
  • Dymaxion/blimp body
  • flat or concave truncation
That's a great question,and probably above my pay grade.
Stability will be a function of center of gravity,roll moment,yaw moment,pitching moment and center of pressure;and whether you want to design in oversteer, understeer,or neutral steering.
At low speeds,understeer is prefered,and you just give it more steering input.
At high speed you want to weather vane,and cancel out any induced yaw,otherwise the car will get away from you.
The GM Sunracer suffered understeer and they put a series if strakes along the underside of the tail to null out the nose's tendency to turn broadside to the wind rather than into it.
Since the template 'pumpkin seed' has won the World Solar Challenge a number of times,and had to remain stable in the presence of land trains on windy days,it acquits itself rather well under rough wind conditions.
Bucky's Dymaxion Car should have half the drag if it were a half-body (if you ignore the wheel drag).It would bring the CG down and that would frustrate roll.We know there was a fatal rollover incident associated with it,but that was the fault of a real rubbernecking nimrod who collided with it.I don't remember Bucky complaining about handling issues.
The Ford Probe-V is truncated,and with the vestigial fin on the boot,they claim excellent crosswind stability.
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