Miscellaneous Stuff

Gene Pape's Dogfighter leaps away from his electric launcher, which employs automotive power door lock mechanisms. This is Gene's first prototype; construction details below describe the second, even better, launcher. Flying Lines photo.

Fly by yourself

By Gene Pape
June 2020

This is about my remote-controlled self launcher.  I have been intending to build a self -launcher that would work for all kinds of hand-launched control-line models for many years. There are many manually operated ones that have been documented previously but something kept me from copying them exactly because I’m, well, just plain weird.

Most of these have been well documented by Buzz Wilson.  If you’re contemplating building a self-launcher I strongly recommend you read his article before deciding what to build. This is intended not to get you to build the launcher I made, but to provide ideas for yours. When the COVID-19 thing came along, I decided I had to quit thinking about it and get something built. The idea of someone with any kind of germs standing in front of a running engine and spewing those germs all over someone holding the model suddenly became a very bad idea. Coincidentally, at the same time Gary Weems sent around pictures of his self launcher that was actuated using automotive power door lock solenoids. The launcher presented here is my lazy person's approach to copying Gary’s launcher.

The basis of my launcher, the automotive door lock system, came from Amazon (right).

For my first testing, I simply plugged two of the solenoids into the system and bundled up the rest of the wires so they wouldn’t be a terrible mess. It all worked perfectly. If you are uncomfortable with electric things, this is all you have to do to have a working system. This can be used on stooges for models with wheels as well. Since I first saw Gary’s launcher, I have seen others apply the door lock solenoids to various other control-line model launching systems. This system requires a 12-volt power source to run. I used a 12-volt AGM battery that I have used for years as the power source for my power panel. The pictures show the workings.

The model is held in place by a piece of 1/8” nylon rope. The cord passes over the top of the model and down through a generously radiused ¼” hole drilled at an angle through the top of the rear of the side board at an angle to come out on the outside of the frame. Another ¼" hole is drilled near the bottom of the side rail to allow the rope to pass through the center. Tension is supplied by a bungee cord hooked to screws. The angled pins help the pins stay in the hold-down straps until the solenoid pulls the pins. The basic frame of the launcher is made from a 2x4 and two 1x4s to mount the workings.

The photo shows the side view of the rails. The black parts are the solenoids. All photos by Gene Pape except as noted.

The pins are shortened from the pins provided in the kit and an adjustment bend was needed to get them to line up with the brackets also provided in the kit. The brackets had to be drilled through and are mounted with 4-40 screws. The solenoids are mounted using drywall screws. The rails are capped with ½” pipe insulation.

This shows the top view of the launcher including the hold-down straps and bungee cord tensioner.

This is Gary’s launcher that I used ideas from, seen at the Eugene Prop Spinners' Can Do Ranch flying field. My stooge is set up near my pickup in the background.

A few years ago, Mike Hazel came out with a portable table that was very heavy duty and very easy to set up and put away.  I decided at that time one of those tables would be the perfect platform for whatever self-launcher I would build and got one from Amazon). The clamps shown that I use to hold the launcher to the table come with the table.

This folding table from Amazon holds the launcher with its built-in clamps.

This is also available with extending legs so you can get your launcher a bit higher if that seems to be desirable.  I have enjoyed using this table at the field since. Photos below show the table, frame and mechanism holding a plane.

Front view.

Side view.

Another view of the table, frame ande launching mechanism.

Front view with plane.

Rear view.

My second prototype uses a 3-cell LiPo battery which is more compact. Where the first one was built to clamp to the heavy-duty Keter table, this one is screwed to a collapsible sawhorse. It requires the extra weight of my heave toolbox to hold it down (below).

Once you have this all assembled at the field with the model on it, operation is extremely simple.

You extend the pins. You slip the hole in the strap over one of the extended pins. You then pull the slack out of the strap on the opposite side and slide the hole in that strap over the pin on that side. Check to make sure the model is centered on the launcher and solidly mounted. See photos below.

Prototype 2 uses a LiPo battery.

Side-rear view shows a plane mounted.

Front view shows the tensioning bungee cord.

Side view shows the mechanism.

Rear view.

Now you can start the engine. Once it is running, I walk around the outboard side of the model and around the back of it to the handle. Once you have the safety thong with the remote attached on your wrist and the handle in your hand, you just press the button on the remote to retract the pins on the launcher and you’re away.

Of course, as with anything else, safety comes first.  Always secure the handle when no one is holding on to a model with a running engine. I attach the remote to the safety thong and use a large screwdriver through the safety thong to pin it to the ground while starting the engine. A tent peg would be even better, but I haven’t been able to find where I put them.

Whenever you use a stooge of any kind, secure the handle to the ground in case of a premature launch while you are walking to the handle. This shows the handle staked down with a screwdriver through the safety thong (assures down line will bring the plane down immediately); remote-control fob is attached to the thong.

This is what it's all about -- you get to fly without sharing germs with a pit crew! Also handy when you want to go flying and there's nobody else available. Flying Lines photo.

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This page was upated June 17, 2020