This F1D design set three records in a single flight
Bob Randolph’s Top Cat 90L-1 set
three records during one flight
on May 3, 1991, establishing the
Category I world record and setting
new AMA F1D and Stick records with
a duration of 32:09.
The model’s predecessor, the Top Cat
90, was a world-record holder, but Bob
wanted to design a model that would
stay under the 106-foot beams at the
Johnson City East Tennessee State
University flying site and fly longer than
40 minutes. He designed the Top Cat
90L-1 as a low-ceiling version of the
original.
The changes were slight, but
important. A 22 x 361/2 propeller
replaced the original 221/4 x 40
propeller; the motor stick was shortened
by 11/2 inches; and the tailboom was
lengthened by the same amount.
Bob also changed to a suspended
stabilizer and nonsoldered variablepitch
propeller hub. The gossamerlike
covering was light silver and gold
Rodemsky microfilm and the propeller
was translucent orange MonoKote.
It was noted that unless modelers
were experienced Indoor fliers, they
might have more flying fun by increasing
most of the indicated wood sizes by 20%
to 30%. The author also suggested that
performing partial-motor tests on this
Indoor airplane was of great
merit; full-motor flights
would be slightly higher and
longer because of warm air
near the site ceiling.
Bob noted that the
easy-to-build, adjust, and
fly national and world
record-holding model “ …
brought me great pride and
pleasure.”
This model was featured
in a construction article in
the September 1991 MA.
AMA members can access
the magazine’s digital
archives on MA’s website to
read more about it.
Top Cat 90L-1 is AMA
Plans Service listing 699,
available for $5 plus
shipping and handling. See
page 157 or go to www.
modelaircraft.org/plans.aspx
for ordering information.
Edition: Model Aviation - 2012/06
Page Numbers: 99
