Page 66

There are always a bunch of Thorps at Oshkosh.  In 1963 the late John Thorp designed the classic all metal Thorp T-18.  Of more than 1500 plans sold, about 400 were completed.  Although designed for an O-290 it could take up to an O-360 the latter of which gave an "honest" cruise speed of about 185 mph.  In 1984 Lu Sunderland designed the S-18 as an improvement over Mr. Thorp's design.  The S-18's new wing lowered the stall speed by 7 kts over the Thorp T-18.  The new wing also provided a more gentle stall with more pre-stall buffet.  The S-18 fuselage is 2" wider and 5" longer than the standard T-18.  Cruise speed is similar to the T-18.