108 MODEL AVIATION
Safety Comes First Dave Gee | [email protected]
Manual arming switches for electric-powered models
Also included in this column:
• Gas and glow engines require
ventilation too!
• Internet wisdom
• Mobile starting bench
• Stooge talk
• A case of “pit hit”
Left: Dave Seale used some lumber and
his imagination to create a classy mobile
workstand for home use.
Above: Internal-combustion engines make
harmful exhaust gases—even the little one
in this helicopter. Don’t run them in
confined spaces!
Left: Carl Rankin’s soda-straw and clingwrap
electric RC model spans 7 feet and
weighs less than 2 pounds. It’s beautiful in
flight!
A READER suggested using an arming switch on an electricpowered
model to prevent accidental motor runs, and since then I
have heard from several savvy electricians about how our modern
power systems do not like such switches. Steven Nicholson wrote:
“An inline switch may work on a small current ESC (5 or
maybe 8 amps), however, as you progress up (in power) this will
be a problem. I lost one airplane on take off due to a switch
malfunction.
“The switch acts like a fuse link. With electrics using 20 to
110 amps, you would have to have a switch that handles very high
current.”
My models tend to be small enough not to cause switch
problems, but there have been some serious unexpected incidents
with powerful motors and I still think a manual arming switch is a
good idea.
10sig4.QXD 8/22/07 12:44 PM Page 108
dustry
people showed me new heavy-duty
switches and arming plugs that are being
marketed for such use. Since I wrote this
roughly three months before the
magazine’s cover date, these products may
be available by the time you read it.
On the topic of three months, winter
weather will be here soon. That means
many modelers will be working in their
cozy, warm workshops.
Do you ever bench-run your gas engines
in a place with limited ventilation? We
know better than to do that with an
automobile, but a harmless, little model
engine seems different, right?
Look at the picture of the hovering
helicopter. The weather conditions were
just right for the exhaust to be visible, and
you can see how many cubic feet of fumes
are made in only a few moments of
running.
An internal-combustion engine produces
carbon monoxide and other dangerous
gases. You can’t tell what the danger level
is solely by sniffing!
When you are considering whether you
should test-run that new engine out in the
icy gales or in the comfort of your
basement, please remember the picture of
exhaust smoke pouring out of that
helicopter engine. Leave yourself plenty of
breathing room!
The Internet is a great place to share
aeromodeling information and make
friends. Many chat rooms and bulletinboard
Web sites are devoted to various
aspects of our hobby.
I can’t possibly monitor them all, so a
helpful reader sent me a discussion thread
about one of my favorite subjects: eye
protection. Forgive me for quoting these
messages anonymously since the writers
didn’t know their wit and wisdom would
end up here.
“Hey guys, just had a scare this
afternoon with my Dremel. I was cutting a
steel RC link and my cutting wheel
shattered and a piece hit me in the lip and
drew blood! Felt like I got punched.
“I was wearing my safety glasses but the
thought of what would have happened if
that shard had hit my eye really freaked me
out. Don’t get me wrong, I love my Dremel
but it’s easy to forget how fast those little
attachments are spinning. Stay safe.”
“I like the non-reinforced cutting wheels
because they seem to work better. But for
safety reasons, I’ve been using the fiber
reinforced wheels as they are less likely to
let go. All it takes is 1 millisecond to
change your life forever. Better to be safe
than sorry.”
“I had an issue the other
whether I’m running a drill or cutting
balsa. This has saved me more than once
when fast-moving specks have flown into
my face.
I confess that at times in the past I have
done “just a little bit” of grinding or
drilling without eye protection. What a
dumb move!
For outdoor occasions, following is yet
another plug for Zurich impact-resistant
sunglasses. I am unaware of anything else
like these on the market. They come in
various shades and styles and are
advertised in this magazine.
Once you try these glasses you will
understand my enthusiasm. My pair has
protected me from glare and flying
particles for several years.
I saw a really big flying particle recently,
created by eccentric genius Carl Rankin.
He uses soda straws, tape, and plastic wrap
to build RC electric-powered airplanes.
Carl’s latest model spans 7 feet! It weighs
less than 2 pounds and has intricate
internal spars supporting a cantilever wing.
Spectators commented that the slow,
floating flight pattern resembled a blimp
more than an airplane. This may be the
safest RC airplane ever, with an ultralow
wing loading, ultralow cruising speed, and
a structure that bends without splintering.
Carl assured me that the food-grade plastic
wrap kept the airplane fresh and crispy.
A crisp E-mail accompanied by some
nice photos arrived from Dave Seale. He
wanted to discuss ways to secure an RC