AMA Plans Service Showcase - 2011/03

March 2011 133
Witchcraft AMA Plans Service Showcase
A sport twin designed around .90-size engines
TWIN-ENGINE AIRCRAFT not only have an
unmistakable sound as the power plants hum in
unison, but they also look cool. So it was no
surprise that John Tanzer wanted to design a sport
twin. He set out to produce a model that featured
fairly simple construction, with the ultimate goal of
being easy to fly.
The Witch Craft has a tapered wing, providing
more lift, combined with a symmetrical airfoil,
which improves aerobatics. The tail is slightly
oversized for greater authority and to aid in
controlling the aircraft in the event that one of the
engines stalls in flight.
Wing nacelles are spaced far enough apart to
accommodate propellers as large as 17 inches. You
can purchase nacelles themselves from Fiberglass
Specialties, to simplify construction.
This 84-inch-span model was designed around
.90 glow engines and had a flying weight of
approximately 17 pounds when outfitted with two
O.S. Max .90s and standard-size servos.
Plans show the Witch Craft with fixed gear, but
John experimented with rotating retracts and found
them to be successful. He noted that the aircraft
required no rudder work while on the ground and
was stable in the air. He was impressed by the
aerobatic capability of the airplane and added that
takeoffs and landings were a breeze.
The Witch Craft was featured in a construction
article that was published in the October 1994 MA.
Members can access the magazine digital archives
on the Academy’s Web site to read more about it.
This design is AMA Plans Service listing 770,
available for $22 plus shipping and handling. See
page 163 or go to www.modelaircraft.org/
plans.aspx for ordering information. MA
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