Safety Comes First
A different kind of hot glue
Dave Gee | [email protected]
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 countertop. 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 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.
Dremel EZ Lock cutoff-wheel system
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.
- 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.
- 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.
- 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?
- 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 modeling-related 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 radio-controlled aircraft. It apparently could fire a pyrotechnic rocket via servo control. The seller had posted a photo showing one of the devices 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 computer-generated, 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 pyrotechnic 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!
Sources
- Dave Gee
Box 7081 Van Nuys CA 91409
- Dremel
(800) 437-3635 www.dremel.com
- RCUniverse
- AMA Safety Code
www.modelaircraft.org/files/105.pdf
Transcribed from original scans by AI. Minor OCR errors may remain.
