Posted on 07/24/2025 7:51:23 AM PDT by Red Badger
Mark here. It’s hard to exaggerate the allure of the Cox E-Z Flyer. To a young boy in the late 1970s, the Cox E-Z Flyer was the best toy in the world. It was also loud, dangerous, and doomed.
Why Is This Interesting?
The Cox E-Z Flyer was a control-line model airplane powered by a tiny internal combustion engine. It was attached to two 50’ control lines that ran to a handle. The model airplane enthusiast would hold the handle as the plane spun in a 100’ diameter circle around the pilot until it ran out of fuel or crashed. These two outcomes were equally likely.
Theoretically, the control lines allowed the pilot to perform tricks and maneuvers with the plane by tilting the handle to manipulate the plane’s control surfaces. However, as a practical matter for most Cox EZ-Flyer owners, this illusion of control only served as a temptation to stray from the only prudent flight plan, which was level flight until fuel exhaustion.
Did the pilot get dizzy? Yes.
Could a passerby get snared in the spinning control line such that the plane circled closer and closer on an ever-tightening death spiral until the whirling propeller and the incandescently hot metal engine collided with its victim? Theoretically, I guess. But it seems more likely that the plane would lose vertical control and crash long before this, leaving the pilot and the victim to explore concepts such as fault, responsibility, and liability.
Because the Cox E-Z Flyer began its inexorable motion immediately upon starting, it required two people to operate: the pilot and someone to start the plane. Starting a Cox E-Z Flyer had its own challenges and dangers. The starter would hand-crank the tiny, sharp propeller like an old-time barnstormer. A small spring hooked around the propeller. The starter would spin the propeller backward against the spring, then flick it to release the prop, hoping the engine would kick into life. Frequent mis-starts encouraged the starter to ever more enthusiastic prop-flicking, which increased the chances that when the tiny engine burst into life, the starter’s fingers would be in the path of the propeller. Typing this paragraph vividly evokes the sting of a fresh cut on gasoline-soaked fingers.
Starter/crowd control was this writer’s assigned serfdom—since the Cox E-Z Flyer that came (briefly) into our house was the property of my eleven-year-old brother. At age nine, all I got to do was struggle to start the plane and then hold back the curious neighbors, dogs, and occasional motor vehicle traffic as my brother spun his orbits around our cul-de-sac.
My crowd control efforts were made easier by the shockingly loud buzz emitted by the tiny 0.049 cubic inch two-stroke engine. These adorable powerplants are called “glow plug” engines because the fuel is ignited by the glowingly hot engine itself. In the unlikely event of a successful flight, the enthusiastic pilot would no doubt want to fly again immediately, leaving the starter to try to refuel and re-prop an engine that was literally hot enough to ignite its own fuel. A precise blend of fuel and lubricant was required, both helpfully sold and supplied by the Cox Model Engine Company.
Cox 0.049 cubic inch glow plug engine
One day, after my brother had pulled off another flawless full-tank-to-exhaustion rotating flight on our cul-de-sac, I managed to wheedle and whine enough to get him to allow me to fly his plane. Our very poor idea was for him to begin the flight (I’d prop and start the plane as usual), then I’d dash to the center of the 50’ radius, grab the control handle from him, and continue the flight. This did not go as planned. The moment of slack created when we handed off the controls sent the plane into a climb, then an unrecoverable dive. The little plane crashed into the pavement and burst into dozens of pieces of sharp plastic and hot metal. My relationship with my brother suffered similarly irreparable damage.
Control line model aviation is a rich and rewarding hobby pursued with great skill and care by enthusiasts all around the world. The Cox E-Z Flyer may have been an excellent model for the hobbyist, but as a toy for children, it was terrible, sure to end its short service life in tears and flame. You may be thinking that the Cox E-Z Flyer was never intended for children and that it only fell into the hands of kids who adroitly manipulated their parents into buying them a gift intended for adults. But no, dear reader. Take a look at this:
This is the back of the box for the Cox E-Z Flyer. How old is that hobbyist? Nine?
The Cox Hobbies company merged with the equally exciting Estes Model Rockets in 1996, but competition from inexpensive electric-powered, radio-controlled aircraft spelled the end of production soon thereafter. Dedicated fans of Cox’s tiny internal combustion engines keep a market alive for parts and fuel, and Cox E-Z Flyers are available from time to time on eBay. Serviceable models can be found for about $200. (MJS)
Quick Links: (AT SITE)
This introductory video for control-line flying, “Wired for Excitement”, is narrated by the great John Facenda of NFL Films fame. (MJS)
Brodak.com covers all things related to control-line flying (MJS)
The Wikipedia page for the Cox model engine (MJS)
First flight video of a New-In-Box Cox E-Z Flyer of the same type and model that I famously crashed. “They don’t make educational toys like this anymore”- Educational? (MJS)
Thanks for reading,
Noah (NRB) & Colin (CJN) & Mark (MJS)
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Mark Slavonia (MJS) is an investor, a pilot, and an avid cyclist. He wrote about radio altimeters, rowing machines, traveler’s checks, and more. He posts other things that are interesting on his website.
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I had several as well. Caught my fingers in the prop at start up more than once and still have all my digits....taught me the importance of safety.
At one point I had a a bunch of motors but no planes or money so I tried building my own....mounted the engine on a balsa wood plank and
Used flexible cement to attach a horizontal stab/elevator, rigged up a bell crank and off it went....flew just as well as any out of a box.
I built several of those and never bought another one again.
That hobby more than likely was the basis for leading me into a career in aviation maintenance.
I also recall the finger cuts from starting them things then the gas getting into the cut boy did that sting
I never used 50 ft lines. More like 25. Put a ring on the tail of planes with a pull pin on a string so I could launch on my own. Never had a Cox plane but built many. Combat with ribbons was fun.
Pussy….
I still build sugar rockets. Flew Estes rockets in the 60’s.
http://www.nakka-rocketry.net/index.html
My neighbor had one in the early 70s. While using it, his mom came out and got too close and it whacked her in the head. Really opened up her noggin. No one thought of suing anyone, just a lesson learned.
Speaking of Cox and Estes, we did try to get one airborne using a pair of Estes engines stuck under the wings like tiny JATO bottles. That was an exciting three seconds.
What BS, I had one, played with it a lot. A few finger ouchies but great fun back then.
In what world was that??? The Cox .049 ran cool enough to touch while running.
It took about 15 minutes of playing with our new set of lawn darts in our backyard before I discovered that you could stick one deeply into a telephone pole if you threw it hard enough.
They were confiscated by my dad a few hours later when he found out my aim wasn’t so good and missing the telephone pole meant hitting the garage behind it.
It’s all a part of the game.................
😂🤣😂.............................
We set it up outside.
I told my father the instructions said to set min throttle till one got used to it.
He ignored me. Plane took off, went vertical and looped noesdown into the ground.
Exact same thing happened to me. My father got me a P-51 for my 10th birthday (1958). And after I made three successful flights, my father wanted to try.
Same as your father. Straight up, straight down.
He bought me another one, and never asked to fly it again.
I had a propeller driven car, I can still see the scar on my left index finger. It’s a good way to learn about gas engines, and safer than a motorcycle.
I vividly recall the smell of the the exhaust! And the noise...
“Lawn darts”
“Heads up!” around Lawn Darts was a serious thing... lol
Brought to you by the creators of “Bag-O-Nails” and “Bag-O-Sulfuric Acid.”
I spent a lot of hours building and flying U-control airplanes. It was a great hobbie. Much better than staring at a smart phone screen.
> These adorable powerplants are called “glow plug” engines because the fuel is ignited by the glowingly hot engine itself.
Not exactly. They were called glow plug engines because they used glow plugs to get started rather than spark plugs. Basically, they were tiny 2-stroke diesel engines that, once started, kept running on compression ignition until they either ran out of fuel or were mechanically stopped (i.e., crashed). They were loud because the exhaust vented straight out of the cylinder on the downstroke.
Speaking of menaces that were sold as children’s toys: did anyone else here ever mess around with Jetex engines? Now *those* were a danger to life and civilization!
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