A Custom Radio And Telephone System For Glider Winch Operators

The control panel of a glider winch

While gliding might be the most calm and peaceful way of moving through the air, launching a glider is a rather noisy and violent process. Although electric winches do exist, most airfields use big V8-powered machines to get their gliders airborne. [Peter Turczak] noticed that the winch operators at his airfield often had to juggle multiple communication channels while pressing buttons and moving levers, all with the deafening roar of a combustion engine right next to them. To make their life easier, he built a single communication device that combines multiple radio inputs and an analog telephone .

A stack of circuit boards next to an old phone ringer
The inside of the cabinet. Note the classic phone ringer

The main user interface is a sturdy headset that dampens engine noise significantly. This headset is connected to a cabinet that contains several modules connecting to different audio sources: an analog telephone line, an aircraft radio receiver, a PMR handheld radio, and even a music source in case the other lines are quiet. The system contains automatic switchover circuits based on a priority system, ensuring that important messages are never missed.

The electronic design is based on classic analog components like NE5532 and TL084 op amps, all mounted on small, custom-made PCBs. Audio transformers are used to avoid ground loops between the various signal sources while relays mute sources that are not prioritized. To ensure seamless compatibility with the telephone network, [Peter] used components from old desk phones, including line transformers, a DTMF keypad and even a mechanical ringer. His blog post is full of details that will be of interest to anyone working with op amps and audio, such as how to stabilize an amplifier that has significant wiring capacitance on its input.

At heart this whole project is “just” an audio mixer, although optimized for a very specific purpose. But designing even a simple mixer is by no means an easy task, as we reported a few years back. If you’re more into winches, you’ll be delighted to find that smaller ones can also be used for sledding and even wakeboarding.

15 thoughts on “A Custom Radio And Telephone System For Glider Winch Operators

  1. Glider winch launches are noisy for only one person. Nobody else with any sense will be anywhere near the launch cable; everybody else is a mile away :)

    Do try gliding. In a single flight you can fly alongside birds of prey, pull 3G continuously for a minute or so[*], and experience zero G. And launches are 0-50kt in 5s, which beats most cars.

    [*] and if there is someone else doing the same thing at the same altitude, you keep your distance by looking upward at the top of their head (you are banking at 70degrees :) ).

    1. I approve of this message. Go try it. It’s very different from powered flight. Leaving the fuel-to-noise converter on the ground makes a big difference.

      You’ll find why glider pilots are the coolest pilots around. We don’t need a big fan to keep us from sweating!

      1. Can we please officially rename Bluetooth speakers/boomboxes/whatnot to “fuel-to-noise converters”? ;-)
        I mean “fuel” doesn’t really fit but “energy/power/electricity-to-noise …” doesn’t sound as good.

  2. As a glider pilot and winch operator I say it’s a nice project but I personally don’t think I’d want to use it. There is no way of knowing which line will have priority and the only way of deciding that is by listening to them all in real time. The priority also changes based on whether you’re actively winching, waiting for a start, waiting for the cable car to get to you or finish running out the cable, etc. You get pretty good about tuning out other noise to hear whatever you need. Germany requires the telephone line (old and outdated regulations imho), the PMR radio is probably for communication with the cable-car driver and should not be needed very often, nor when the winch is running, the aircraft radio is redundant and not really required. German clubs usually use it to signal the speed during launch to the winch driver to either slow down or speed up but I find the Dutch method of waggling the tail to signal too fast or pressing the nose down to signal too slow to be both faster and more accurate. On the winch the speed indications usually sound as “SCHHHKKKKTTRRRRR” with a note of engine noise and cable twang.

    From the photo’s I’m guessing they’re using a winch built from a Tost 2-drum, the same winch my club used to have. They’re noisy as frick (a nearly straight-pipe Oldsmobile Rocket 455 bigblock V8 will do that) but the tactile and audio feedback from them is unparalleled. Get attuned to it and you could launch an aircraft blindfolded. With a headset on muffling the crackling of the cable onto the drum and some of the engine notes probably not so much. There should be no “juggling multiple channels” during a launch. Single switch for the radio (ours was foot or hand operable just by nature of where it was located) and just ignore the PMR radio as it doesn’t matter. Only thing that matters is the guy on the telephone. Aircraft radio is optional and only requires hearing in the background

    Oh and I’d want either my own headset or not use it, because I’m NOT sharing a headset with I don’t know how many people who’ve all been wearing it sat on top of a hot V8 in the blazing sun in 25+ C degree weather. The hassle of putting it on and off every time you get in or out of the winch is annoying too.

  3. The club I used to fly at considered voice comms to the winch operator distinctly inferior for this reason. We had a round board painted half orange and half white. When the pilot was ready for the cable slack to be taken up, someone waved the board with the orange side down. When they were ready to launch, they switched to waving it with the orange side up. It’s simple but quite hard to get wrong.

    1. Our clubs usual method was a strong lamp/light. Flashing light = take up slack, full light = all out/go, light out = stop.
      I’ve done the “lollypop” method too both from the winch and the start and prefer the light. Easier to see and less faff. The only downside to not having voice comms at all was not knowing what plane was attached to the other end if the start line wasn’t clearly visible from the winch (due to a rise in the field or something). Doesn’t matter so much if it’s a mix of ASK-21s, Puchacz and Juniors, but less than ideal when you start throwing very light planes like a Std. Libelle or a Ka-6 in the mix that overspeed if you just look at the throttle wrong.

      1. I run the winches at my club. We mainly use an 11,6 litre diesel engined winch.
        For Comms we use a flashing light system backed up with a two way radio.
        The radio is used to confirm glider type and unless the winch driver receives this info, he/she will not carry out the launch.
        Long on/off flashes denote ‘take up slack’, short flashes denote ‘all out’, and a continuous light denotes ‘stop’.
        Speed is a matter of personal judgement with yawing by the pilot indicating ‘too fast’ and a positive lowering of the nose indicating ‘too slow’.

        1. If u have a radio voice connection between takeoff, cable car and winch there is no need for light or paddle signals: type of plane ready – rope straight – ready … thats sufficent and we had no probs last decades. happy landings!

  4. “Gliding (…) the most calm and peaceful way (..)” – this is quiet obviously written by someone who is not a glider pilot ;-)

    Just give it a try! Preferably with some aerobatics ;-)

  5. Since there are so many glider pilots I have a question I have always wondered about. Why don’t gliders use JATO rockets to get into the air? Cost, danger? Have they ever? Just curious and since the experts are here…

    1. Main reason is cost, missing control once it is fired and waste management once it’s dropped (you can’t keep that thing out of a sleek glider when empty).
      Superheated water rockets would solve the control problem even if it’s only on-off. It has been tested on gliders and also on military jets to replace chemical JATO… But again you need a kind of trajectory control once your high pressure tank and rocket is dropped 500 m above ground…
      Another problem is that it might be more than a bit noisy… And you need electric power to superheat your water cylinder in a controlled way to avoid a decent blast if the pressure tank burst before takeoff.
      Self-launching gliders with 2 stroke engines and retractable propeller pod are relatively common but a bit more expensive to buy. Electric versions are available… And you can fire it any time during flight to avoid an outlanding…

    2. Yep. Cost. In US when I was active an aero tow to 2500ft AGL was about $50. I was part of a club so for $800 a year dues I didn’t even have to pay rental fees for our gliders. Far and away least expensive way to fly. Cheap even.
      Also complexity. Gliders are dead simple aircraft. Primary flight controls, usually spoilers or sometimes flaps. That’s it. Occasionally retractable landing wheel. Once you start adding stuff you might as well fly powered. …
      There definitely exist “self launching” gliders that use, usually, an ICE on a boom that deploys up and down. Never flown one but the added complexity as well as drag plus small performance penalty even when stowed makes them less popular than you would think. As a really really rough example, an older medium performance glider may cost about, oh, $30k to buy. A self launcher would add like $80k to that. Very roughly. Point is a big difference.
      Go fly a glider.

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