This shows the outside of the gondola. We enjoy sticking our GoPro
cameras on our aircraft to capture some great aerial footage.
Inside the gondola are three Castle Creations
Mamba Max Pro brushless speed controllers,
a Spektrum AR500 receiver, and a large servo
with rubber belt and pulleys for the main motor
pylon rotation. Two E-flite Power 15 motors
power the 8 x 6 propellers.
Click here to
see more photos of
blimps in different
We continue filling until the aircraft starts to take off again.
This is what we call positive buoyancy, but it looks pretty saggy
and underinflated. If we are breaking in a new team member,
this is when we usually tell him or her to start blowing in the
tube to make the envelope tight, which can provide hours of
entertainment and usually ends with someone unconscious on
We generally hook up a vacuum cleaner, switch it from “suck”
to “blow,” and inflate the aircraft to the firmness of a pool toy,
but not tight enough to pop a seam. This mixture of helium and
air is what we fly with when we have an aircraft with unneeded
buoyancy. If we need more buoyancy, we simply add more
helium and less air.
The gondola is the heart of the airship. It contains a mixture
of RC model parts. We have several gondolas from different
manufacturers. Molded plastic, hand-laid carbon fiber, flower
pots from Home Depot—anything goes if it works.
The most common setup is three motors: one in the tail that
can go forward or reverse, and two main drive motors mounted
on the gondola that can rotate together more than 180° using a
large servo, from up and slightly back to straight down. I usually
prefer the main engines that have the ability to go into reverse,
which requires a set of RC car ESCs.
Because blimps don’t fly fast, there are
no elevators or rudders cut into the tail
fins. There is insufficient
airflow to make them
useful. The tail uses a
propeller that spins in
both directions to swing
the tail either way. The
blimps will always turn
in one direction better
than the other with this setup, but I have an airship with two
propellers stacked on top of each other in either direction,
which allow it to turn fairly well.
For control, one channel handles the tail, left or right. One
channel controls the main motors, forward and reverse; one
channel drives the main motor rotation, up and down. Our
transmitters are set to Mode 2 on most of our blimps, but the
left throttle ratchet controls the motor rotation, so we can set an
angle on the main motors and lock it in.
The right vertical stick controls the main motors: up for
forward, down for reverse. The right horizontal stick is for the
tail, moving in the direction you press the stick. You might think
we would be using Spektrum DX18 transmitters or something
similar, but we could probably fly most airships with the
In actual flying conditions, the ability to have servo endpoint
adjustment and telemetry makes setup and flying much easier
and more dependable. A good compromise between cost and
features are the middle-of-the-road transmitters. Each airship
has its own transmitter, and we currently use a Spektrum
DX5e, a DX6i, a DX7s, a Futaba 7C, and a Hitec Aurora 9,
but we have a 22-year-old practice aircraft still rocking a four-
42 Model Aviation MARCH 2014