F-15 Vertical Tail Revisions & ‘70 Tail Configuration

Jack Abercrombie sent along an interesting comparison chart of F-15 tail development size and placement plus a little known tail configuration from 1970.

His note said:

“Here are a few pages from MCAIR Report A0270, 30 Jan 1970 describing the new configuration (at the time) with the nacelle fences for directional stability improvement.  Note that the configuration includes the middle size vertical tails (55 square ft each--larger than those of the 1969 proposal which were 41.4 each) and almost the original Ventrals (21.4 sq ft vs 20 sq ft per).  The fences helped through improvements to the sidewash characteristics, but not enough.  It was more than a year later (Apr '71) when the ventrals were removed and still larger verticals (the current 62.6 sq ft per) were incorporated.”

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