Launch Sequence Explained

X-Plane’s “out of box” winch launch experience

When you select a glider, you have the option to choose a winch launch as your launch method (the other being an aerotow). When Winch is selected, the glider appears at the chosen runway position with the cable attached and the wings level. If you do not launch within 30 seconds, one wing will drop to the ground which is not a safe way to launch – particularly on grass strips where the wingtip might catch in long grass and groundloop (recommended maximum 4 inches). None of the above is standard real world practice

The X-Plane Winch experience is further hampered by the fact that

  •  The winch is revving its guts out at 300 BHP (check the datarefs) and
  • A message pops up on screen saying “release Brakes to initiate launch”

Now the problem is that the ASK21 – and indeed many gliders in current production –  have their airbrake coupled to the wheel brake. Closing the airbrake is part of the pre-flight checks, but unfortunately it’s not THE LAST pre-flight check, so when you close the airbrake, X-Plane will start to launch the glider and you will still have your canopy open. Moreover, winches are never parked up for the day with their engines revving at 300 BHP just waiting for a glider to release its brakes. For one thing we would burn out £18K engines in less than a season and for another 300 BHP is Waaayyy too powerful and is probably the reason that every winch launch in X-Plane will send you supersonic. (in real life – anything over 100Kts and both the aircraft and the pilot are at risk of irreparable damage)

Real World winching 

A glider will be parked at the launch point with a wing down with NO CABLE attached. The pilot climbs into the cockpit  and will then be required to complete a series of pre-flight checks before closing the canopy and asking for the cable to be attached.

From the point at which the cable is attached, responsibility for the launch will be in the hands of a launch controller. Essentially, he/she is where the buck stops if anything goes wrong.

How X-Winch improves the realism.

So, with X-Winch when you start a glider flight:

  1. The glider will appear and the canopy will pop open. This is by design and will allow you to complete the pre-flight checks – which includes closing  and locking the canopy.
  2. The script also sets the winch BHP to zero so there’s no risk of you closing the brakes and being catapulted into the air unexpectedly
    Once you have completed your pre-flight checks and are ready to launch, press the key/button you assigned to start the launch sequence. If you didn’t assign a keystroke or button, open the popup window and click “Hook On”

When the launch sequence starts, the following will happen.

  1. There will be an initial check to ensure you’ve closed the canopy. If it’s not closed there is a warning message and the sequence stops. Rectify the mistake and restart the sequence REMEMBER – If you are flying an open cockpit glider, you still need to complete the final “C” in C.B.S.I.F.T.B.E.C. by declaring “Canopy Not Present” (See button assignments above)
  2. There will be an initial check to ensure you’ve closed the Airbrakes. If they are not closed there is a warning message and the sequence stops. Rectify the mistake and restart the sequence
  3. With canopy and airbrakes closed, you will hear the cable being attached and a voice saying “Cable is on and secure…. You have a weak link” (See Notes on “Weak Link”)
  4. After a short delay of about 4 seconds, you will hear the launch controller say “All clear above behind and in front …. Take up slack” This requires a little explanation. In the real world, the launch controller will check the skies to make sure there are no incoming gliders on circuit. Once he is satisfied that it is safe to launch, he will tell you. The phrase used is the recommended phrase in use at UK gliding clubs. You may create your own sound file to reflect the standard practices in your own country/club.
  5. After a further short delay of about 4 seconds you will hear the launch controller say “All Out”. The aircraft will then begin to accelerate away

The “Take Up Slack” phrase is there for the pursuit of reality. In real life, cables are hardly ever pulled out directly to the waiting aircraft. Mostly, they are pulled out in twos or fours depending on the winch configuration (you’ll notice, our SkyLaunch winch has two drums) and usually pulled to the side of the launch-point vehicle – maybe some 30-50 mtrs away.

When a glider is ready to launch someone will drag a cable over to the aircraft and there will be some slack in the cable. When the winch driver receives the “Take Up Slack” signal, they will put the winch in gear, apply a small amount of power to take the slack out of the cable so  that when they receive “All Out” and apply some serious acceleration, there is no “snatch” at the aircraft end. A “Snatch” could result in the pilots head banging against the bulkhead behind them causing loss of control of the glider.