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BJ-1B 'Duster' Sailplane
The 1-26 was a nimble, responsive and forgiving sailplane, but
with a best L/D of 21.5, its performance was limited. While Hank
Thor had completed successful badge and Diamond flights in the
1-26, he realized how challenging such flights were - most soaring
days are less than ideal, and pilots don't want to be limited
to a 10-mile radius around the field. A simple, compact sailplane
with a best L/D in the high twenties would have obvious appeal.
 Every
feature reflected Hank Thor's' desire to make the best possible
cost /performance /utility tradeoffs. No component was over 18 feet,
mindful that it would probably be built and stored at home, most
likely in a garage. The wooden structure matched the tools and skills
of many amateur builders. (Jim Maupin once claimed that it could
be built with only a saber saw, disc sander and 3/8" drill.)
The plywood kit made fast assembly possible, and gave a smooth exterior.
The canopy was a plexiglas flat wrap, eliminating the need for molding.
The fixed center section of the wing kept the outer panels light,
and made the Duster easier to rig. The wing had a high aspect ratio
(17.4) for a wooden homebuilt glider, which gave it the look of
a "real" sailplane, especially in the air. Everything
was optimized to make the Duster appealing to the motivated enthusiast
home-builder.In 1973 the Duster Sailplane Association was formed, and the Dust Rag newsletter provided a sense of identity for builders. By 1974 over 150 sets of plans had been sold (in the US and 10 other countries), and a handful of Dusters had flown. As completed Dusters began to log time in the air they demonstrated the performance that was Hank Thor’s initial objective. The time required to complete a Duster varied greatly. Hank Thor’s initial estimate was 800-900 hours. Two editors of the Dust Rag reported different experiences: Bob Walters spent 950 hours spread over 13 months, and doug Bell took 1600 hours over 8 years. One exceptionally meticulous builder reported 3,400 hours! The record for longest elapsed time is held by Terry Whitford and Peter Raphael from Australia, who reported completing their Duster in March of 2000.
Important links: DUSTER
web link Some interesting gliding stuff.. L/D (lift over drag) is a very handy way to express the efficiency
of a particular glider, and its potential for cross-country flight. | ||||||||||||||||||
In
May 1971, a new 43 foot wingspan sailplane, optimized for the
enthusiast homebuilder was introduced. Designer H. Einar “Hank"
Thor had a vision for a small glider that would deliver simplicity,
docile handling and cross-country performance, all at a modest
price, called the Duster. This small wooden glider represented
8 years of work, all directed toward creating a new design that
would improve on the Schweizer 1- 26.
Although
the BJ-1 was a success in the eyes of its builders, it was not
ready to market. Four years of flying had shown the need for refinements,
Ben Jansson had returned to Sweden, leaving Hank Thor to carry
out the development of the Duster. 
The
result was a new glider with a best L/D of 28, a two-point increase
over the Dyna Mite. Although Ben Jansson was no longer involved,
Thor retained the original "BJ' designation as a reminder
of the role he had played. No doubt this helped initial marketing
efforts (photos of the Dyna Mite were used in early Duster ads),
but it has caused many, even Jane’s All the World’s
Aircraft, to overlook Hank Thor’s primary role. 
Many
were indeed built at home in the garage, and stored there when
not flying. The 7-foot wing stub permanently mounted to the fuselage
made it a bit of a challenge to enclose a Duster trailer. An open
trailer for a design intended to fit into a garage in the first
place is a fair trade. even today. 
