Quote:
Originally Posted by Angel And The Wolf
Was the 5th edition written when the National Speed Limit was 55 MPH? Another 20 MPH should mean a more gradual taper.
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Technically, once the supercritical Reynolds number is reached ( around 20-mph ), the drag coefficient will be constant up to around 250-mph, when compressibility effects of transonic flow comes into play.
The 22-degree threshold is from W.A.Mair's research of 1969. Buchheim et al. went as far as 22.5-degrees on prismatic bodies, when the aft-body constituted 45% of total vehicle length. It's very conditional.
Both limits are effective only if the appropriate 'run-up' contours are respected.
If we had a 'true-length' plan-view image of the trike, taken from above, it would give us much-needed information.
The shape defined by the sweep of an analog clock's second hand, between 12:00, and 4-seconds after, provides the proper run-up.