Background
In 1969, Bob Singer designed the Bum-
bleBee 1/2A boost glider to beat the Com-
petition Model Rockets (Howard Kuhn)
Manta, a type of delta flying wing. With its
low aspect ratio wing giving better boost
altitude than "sailplane" wing gliders, it
succeeded, turning in two-minute glides.
The RumbleBee-C is a 4X upscaled
version, with rudder-only Radio Control,
and a "Vector Pod" that offers enhanced
reliability. Tilting the rear of the fixed pod
down by 2.5 degrees offsets the "down mo-
ment" of the normal thrust line, to ensure a
straight boost. The motor module is eject-
ed with a streamer, providing CG shift for
glide trim. This is actually how the first
front engine BGs worked. I find it lighter
and more reliable than pop pods.
RC boost gliders have a reputation of
being hard to fly. FAI S8 RGs can be, due
to marginal boost stability. The only CG
shift comes from propellant burn-off, with
some up elevator at apogee providing the
trim adjustment for glide. Boosting an FAI
S8 RG can be a terror, because the elevator
must be constantly "jinked" to provide ver-
tical flight. Beginners often just loop them
into the ground.
38 MAY/JUNE 2017 SPORT ROCKETRY
by John Fleischer NAR 14848
BUILD THE
Rumblebee-C
Rumblebee-C
Top view of the RumbleBee-C
Radio Control Boost Glider.
