High Rock Launch Discussion

A while ago, a pilot experienced some problems launching at High Rock in light winds. No damage down. However this prompted a discussion on the listserver about launching at High Rock. Considering the impending High Rock fly-in, we hope reprinting excerpts from some of our experienced pilots will be helpful. Interestingly enough, there actually seems to be some consensus. Read on:

Greg deWolf:
With the launch conditions of 5-8 mph I would have been at the edge of the ramp. If I felt the need to run it out if conditions were lighter (1-2 mph) then I would not have had the glider slightly turned into the North cross. Probably totally unnecessary anyway since it was so light.

Starting a couple steps back from the edge of a ramp in a crosswind is the most difficult launch imaginable. With the nose pointing into the crosswind, one wing is out over the end of the ramp in the lift and airflow, and the other is in a shadow. As soon as the glider comes off your shoulders, the forward wing will rise and the wing over the ramp will drop into even more stagnant air. This is even true if you are standing on the edge of the ramp, nose pointed into the cross, unless you can tilt your wings -- outward wing down, inward wing up -- so that they are balanced. (It is difficult to imagine how this could be accomplished and still have a place for the wire crew to stand unless the wind was only minimally cross.)

If there is lift at the front edge of the ramp then it is of paramount importance that both wings enter that lift at the same time. In general, this can be accomplished in two ways. Start at the back of the ramp, forcefully point the glider down the ramp and keep the glider on your shoulders, maintaining yaw control, till you reach the end of the ramp. (Holding the glider pointed down the ramp will become easier as you pick up speed in your run and the relative wind rotates towards coming more straight up the ramp.)

The other is to let the glider point into the wind -- adjust wing tilt (lifting wing down, falling wing up) until they are balanced and running straight down the ramp fast enough that the relative wind is approximately straight in by the time you reach the end of the ramp. Strong runs are needed for both approaches.

Never run across the ramp as this will insure that one wing enters the lift at the end of the ramp first, and don't let the glider off your shoulders until it is pointed into the relative wind.

In the 5-8 scenario it is difficult to figure what the best approach would be without knowing how cross it was and whether the air was more vertical or more horizontal. Launching from the edge of the ramp has the advantage of getting you away from the ramp the quickest. Remember that if the glider is not pointed into the wind, that you will most likely need to correct at least a little for a turn into the wind. Right cross will put you into a right turn -- prepare to shift left a little.

Marc Fink:
High Rock is not really a ramp, but a true cliff launch. I've been flying there actively for almost ten years and I personally feel it is one of the safest launches we have in the region--if not the safest.

The most important aspect of launching at HR--as anywhere else--is maintaining the proper AOA. Complicating this picture a bit is that the AOA will need to change somewhat as the glider crosses the front edge of the "platform" where the AOA relative to the apparent wind will change.

In the many calm to even slight tail launches that I've done at HR I've found that the benefits of starting "far back and running hard" are negligible--and to the contrary can be more dangerous. Since you only have about 4 extra steps there is no way that you're going to get significant extra airspeed without a "forceful" run. The probability that the pilot will push the nose up as they jack-rabbit their launch goes up significantly in this scenario.

I've found that you can safely launch from near the edge even in near calm conditions--it is just a matter of how much of a dive you're going to trade for airspeed. In these conditions I will occasionally start at near the back of the platform, but the initial steps are simply to get the glider moving smoothly with wings level and proper AOA--which is far more important IMO than getting an extra mph or two while risking pushing the nose up while leaning forward as you go off the ramp.

Joe Gregor:
When <pilot> launched it was not terribly cross, it was not much stronger than it had been for other launches that day, and all previous launches were completely without incident. I know, I wired everyone who flew up to that time. <Pilot> was two steps back when the wind picked up a little to maybe 6 or 7 mph, wings were level and steady, neutral pressure on both wings, good nose angle.

Next thing I know I'm getting a buzz cut and watching <pilot>'s right wing scrape the top-right corner of the cube on the way out. I spent some time after the incident scratching my head just trying to figure out what the heck had happened.

Some thoughts:

1) When you see a whole bunch of launches go perfectly it is perhaps easy to get complacent. Several people had launched that day from the same position on the ramp without incident.

2) Just because your wings are stable and level doesn't mean that you are close enough to the edge for the conditions. I had always assumed that if the winds were too strong to launch from a given position you would experience some difficulty maintaining wings level (especially in a cross). Such difficulty would be your signal to move forward into cleaner air.

I postulate now that if you maintain just the right AOA you may be able to maintain wings level even though you are too far back from the edge for conditions. Perhaps, if <pilot>'s nose angle were a touch higher we would have noticed an asymmetrical loading and/or difficulty in maintaining wings-level that would have been a signal to reposition the glider. Perhaps.

I will probably view neutral-neutral with a bit more skepticism if there is any appreciable breeze coming in, and perhaps tip the nose up a fraction of a degree just to test conditions before resuming the proper AOA for launch. Or else, simply commit to launching directly from the edge from now on, and resolve to bag it if conditions seem too light to make this a safe maneuver.