Greetings:
OK, I have a new gripe.
A friend of mine at work builds and
flies radio controlled aircraft, like I do. He happens to be into pylon racing of AT-6
Texans. Encouraged by a pretty good showing at a race at the flying club field in May,
he decided to build a new model for the big September race. His goal is to make this
one as light-weight as possible in order to gain an edge over the competition.
Competition rules require a certain standard kit with a standard engine and standard
propeller. No modifications to the outside shape of the airplane is allowed, and the
engine and propeller must be stock. This "one-design" class is typical of R/C competition
in order to make the skill of the pilot both in building and flying the primary differentiator
in the competition.
In order to accomplish his minimum weight goal, this guy
searched around for the absolute lightest servos, battery pack, wheels, covering material,
pushrod material, and anything else he calculated could save a gram of weight. The most
expensive of the light-weight items was the receiver for the airborne radio. I helped
him with that one, and we got burned by deceptive specifications.
Most standard
5- to 7-channel R/C receivers typically weigh in at around 12 to 18 grams. I recalled
seeing this one from a company called FMA Direct that was advertising an 8-gram 5-channel
receiver, so my friend quickly bought one for $40. It arrived a couple days later, and
we took it into the lab to weight it on the triple beam balance. We were shocked to
see that it weighed 11.5 grams. Now, 3 grams might not seem like a lot to gripe about,
but recall that the sole motivation for buying the receiver was the lower weight. The
Hitec receiver he already had weighted almost 17 grams (13 w/o the plastic case). He
was hoping for a weight savings of around 9 grams, but instead got about 5.
Here
is where the rub occurs. My friend called the manufacturer to ask about the claim of
8 grams (about 0.3 oz), and the representative told that the advertised weight was without
the antenna! How ludicrous! Nobody in the industry advertises a weight without the antenna!
The antenna is about a three foot length of #24 stranded wire with plastic insulation,
and all receivers have one – no exceptions. Some people trim the length to save a little
weight, but not much because the range takes a significant hit. I suppose when FMA Direct
publishes a weight spec for a servo, we had better ask whether that is with or without
the interconnect wires and plug
.
When
an e-mail was written to the company in protest of the bogus specification, the marketing
guy wrote back all indignant about having been called on their deceptive practice. If
you go to the URL listed below, you will see that the company has changed the spec as
a result of this incident. They now list a weight both with and without the antenna.
http://www.fmadirect.com/detail.htm?item=2098§ion=1I suppose I will
give them credit for righting the wrong, but still, those guys have been in the business
for a long time and know what people expect from an advertised specification, and that
weight is a major factor in peoples’ decisions to buy radio gear for airplanes. They
probably figured most people would never actually weight their receiver if the spec
tells them what it is. This episode just further validates the old saying, “caveat emptor.”
