Safety Comes First - 2009/05

Safety Comes First Dave Gee | [email protected]
Also included in this column:
• Dremel’s EZ Lock
• Recycled containers to store
small parts
• Suggestions for preventing
propeller strikes
• RC rocket launchers? Yikes!
A different kind of hot glue
A box of cheese, some breath mints, and thou … Keep small parts
in these neatly nesting recycled containers.
Not as “extreme” as you might think, this aerobatic 3-D model was upgraded to rubberpowered
indoor FF. It doesn’t hover, but it’s still fun.
The Dremel EZ Lock mandrel set cuts and grinds like a champ,
but the author has problems with the locking system.
YOUR CLOSE-CALL stories, suggestions,
comments, and corrections are welcome.
My e-mail address is above, and my mailing
address is in the “Sources” list.
You can even make fun of the 3-D FF
model in the photograph. I got the kit as a
show special at AMA Expo 2009, and I
wanted to see if a radio was necessary to fly
it. It turns out that the airplane does just fine
with a big loop of rubber and a bit of
dihedral. It doesn’t hover well, but it always
gets a double take from the “extreme”
pilots.
Jim Riggle didn’t set out to be mentioned in
this column, but it worked out that way. He
said a friend had recommended Gorilla Glue
to repair a damaged micro helicopter. Jim
wrote:
“As usual, my glue was all hard in the
container but I really wanted to use it and
didn’t want to wait and go to town the next
day. Besides, it’s expensive and the next
container would just harden also. So why
not microwave it?
“Well, one reason is that after a couple of
20-second sessions, it had not only softened
up nicely, but had sprung a pin-hole leak
and started shooting hot glue about 20
inches into the air!
“Good news is that it only got on one of
my fingers and the kitchen counter top. Bad
news is that my wife was watching the
whole performance. Actually, because ‘Mr.
Science’ got a pretty good burn on the finger
she didn’t really give me the heck I deserved
about the glue all over the counter.
“I used ice on my finger, alcohol on the
counter, and am very glad it wasn’t pointed
toward my face. One lesson would be the
microwave isn’t designed to heat everything
and the other might be to do some research
about the properties of the substances you’re
going to heat before you try it.”
I can’t add much to that, except to stress
that heating products that do not call for heat
is generally a bad idea.
In my professional capacity, I once met a
fellow who wanted hot shaving foam but
only had the room-temperature type on
hand. After warming up the can on the
kitchen stove, he found himself wearing
much more of the hot foam than he had
planned, along with some of the shrapnel
from the exploded can. The EMT crew
May 2009 97
05sig4.QXD 3/24/09 12:02 PM Page 97
bravely kept poker faces while treating the
foam-covered chemistry whiz, but I had to
run outside and laugh myself hoarse.
Did you ever notice how most product
reviews seem to be glowingly positive?
The following might break that streak.
Dremel makes some terrific stuff, and I’m
a loyal customer, but the new EZ Lock
cutoff-wheel system was disappointing.
The EZ Lock is a spring-loaded
mandrel that fits specially keyed abrasive
disks. The problem I’ve seen is that under a
modest side load, the retainer can suddenly
let the disk come loose. The disk could
shatter with a more rigid mandrel but, in
my experience, the not-so-secure locking
system on the EZ Lock could be a hazard
by itself.
I recommend this tool for light uses
only. Be careful to apply only straight force
to the wheel to avoid popping the mandrel
loose.
On the plus side, some excellent cutoff
wheels are produced with the special EZ
Lock hub. They are effective on wire and
small metal fittings, such as those we use in
our miniature aircraft.
Modelers seem to collect loads of small
fittings made from metal or other materials.
It can be a challenge to store them in an
organized manner.
An anonymous reader noticed that
Altoids mints come in dandy little metal
tins, and that these tins fit perfectly into a
Velveeta cheese box (after the cheese is
gone). I suppose that if you eat a whole box
of Velveeta, some Altoids might come in
handy.
Recycling these packages provides an
excellent way to keep track of small parts.
It is much better than letting them get lost
in the carpet, as I do, and then finding them
later with my bare feet.
Nickolaus E. Leggett is a reader who does
not mind seeing his name in print, and his
ideas are certainly good enough to share.
He read my recent piece about propeller
strikes and how we should try to avoid
sticking our hands into spinning propellers.
Being an analytical and inventive
fellow, Nickolaus produced some
interesting technological suggestions for
keeping fingers attached to hands. They are
as follows.
1. Paint the tips of the propeller blades a
bright color, to make the propeller arc more
visible. This is a tried-and-true method
with full-scale aircraft, and I think it is
underutilized for models. It’s simple and
effective, but not foolproof.
2. Place the propeller in a duct. That
provides excellent protection and, if it’s
done precisely, the thrust is increased.
Structurally, it is difficult and tough to do
with a tractor configuration, and it’s
impractical for most Scale aircraft.
3. Put a mesh guard around the
propeller. This is a reliable way to avoid
bloodshed, but the most difficult to use.
Full-scale hovercrafts use such screens, but
a model aircraft would have big problems
with the weight and air resistance of the
mesh. Additionally, how would you start
the engine?
4. Illuminate the propeller with a strobe
light that shows it slowly rotating. The
strobe pulse could be synchronized to an
rpm value that is close to the propeller rpm.
I thought maybe Nickolaus was being
tongue-in-cheek with this one, but under
the right conditions the strobe would make
the moving propeller visible. Getting the
light shining on the front of the blade or
making it effective in bright daylight would
be tough. Strobes can also be a problem for
people who are prone to seizures.
My best recommendation is to use
caution when working around powerful
airscrews. Develop good habits and
routines, and then stick to them. Spinning
blades are inherently dangerous and must
be treated with care.
A reader tipped me off to an item
advertised on RCUniverse, which is an
excellent and popular Internet destination
for enthusiasts. I lurk and occasionally post
on the forums there. You can find a
discussion about virtually any modelingrelated
subject as well as new product
information, event calendars, photos, club
information, and more.
The ad in question described a rocket
launcher that could be mounted on a radiocontrolled
aircraft. It apparently could fire a
pyrotechnic rocket via servo control. The
seller had posted a photo showing one of the
things attached to an RC helicopter.
I was aghast at the thought of such a
gizmo! Any competent builder could
produce a similar device, but there are
gravely serious downsides to doing so.
First, it is a hazard to the operator. Our
armed forces take great care with their
airborne weapons, and even so there are
accidents while loading, arming, and
carrying rockets.
Second is anyone nearby when this
gadget is in use. No hobby-level model
could be controlled and aimed reliably
enough to ensure the safe flight path of an
air-launched missile.
Third and most important is the risk to
everyone with an interest in flying models.
It wouldn’t take a mishap, only a news story
with the right “angle,” to turn public opinion
against us all and possibly lead to
governmental interference with our hobby.
If you’ve read this magazine recently, you
know how some elements have proposed
eliminating our “little toy airplanes” to
prevent terrorist attacks delivered via RC
aircraft.
Imagine what ammunition these people
would have to use against us if the
sensationalist media ran with some version
of “Radio-Controlled Death From the Sky,”
featuring footage of some pilot shooting
rockets from his aircraft out in the desert.
For these and other reasons, the AMA
Safety Code forbids rocket launchers and
similar features, even though they might be
great fun and are easy to make.
Here’s where the story gets weird. I
contacted the staff at RCUniverse and asked
about this issue. I identified myself and was
clear about the fact that their answers were
going to be printed in MA.
The first response was, “RCUniverse is
not responsible for enforcing AMA
regulations. The users of RC products are
responsible for their own actions.” I
certainly can’t argue with those statements,
but the response looked computergenerated,
so I followed up with another
message saying so.
To my surprise, I was answered by a
man named John, who said he writes his
own messages. He said that “The item in
question is a launch pad; it is not a rocket”
and that RCUniverse sometimes features
discussions and photos of modeling
activities that violate AMA rules to some
extent. John also gave me a polite warning
about printing libelous material.
I was disappointed by these responses.
Nobody expects RCUniverse to enforce the
AMA Safety Code, but marketing airborne
remote-controlled rocket launchers is tough
to defend.
I would liken it to my local archery shop
carrying poison-tipped arrows and saying
that it is not responsible for the use of such
products. That may be technically correct,
but would you want to live next door to the
purchaser?
I disapprove of building, using, selling,
or publicizing air-launched pyrotechnical
weapons for RC models. Whatever pleasure
they provide is far outweighed by the
danger they pose to people and to our
hobby.
The AMA Safety Code is not perfect,
but every item in it is the result of some
hard-learned lesson. An ironic footnote to
this story has to do with my playing a small
part in helping get the code updated, to
allow for new technology. The process
started with an RCUniverse forum
discussion about techniques that violated
AMA rules! MA
Sources:
Dave Gee
Box 7081
Van Nuys CA 91409
Dremel
(800) 437-3635
www.dremel.com
RCUniverse
www.rcuniverse.com
AMA Safety Code
www.modelaircraft.org/files/105.pdf