Home
Platform Launching (PL)
Of all the towing methods there are to tow a hang glider aloft I most prefer Platform Launching. Of course this assumes that one can afford to mount a winch/reel on your chosen tow vehicle or trailer. If money is a big part of the equation one could easily find Static Towing (ST) as their most preferred method.
If money wasn’t an issue I would still prefer Platform Launching (PL) over Aero-Towing (AT). I even prefer PL towing over Foot Launching (FL).
Each method has it’s own advantages and disadvantages when compared to one another.
During the early R&D years of static towing using the Hewitt Skyting Bridle someone had come up with a “Threaded bridle,” idea.
The desire being to not have a bridle along for the entire flight. Problems with not gathering up the drooping bridle could be snagging the ground when landing or stepping on the bridle during a running landing. (Not nice to look at.)
My HG friend Don Ray agreed we should try it out.
Once released at the keel the bridle, while unthreading, snagged the right front nose wire as Don was gusted 90 degrees to tow and it locked him out. It unengaged itself from the nose wire and next wrapped and snagged at the towline ring near the release for a instant before slipping free. Next on the way to unthreading from the carabineer near his crotch the bridle rope end snapped him on the testicle. (Not sure which one.) It wrapped and hung up at the carabineer near his crotch until Don untangled it to finally be free of the towline and threaded bridle.
When Don landed he said, “We are done with this threaded bridle BS!”
He described the event as having knocked the thrill of flight instantly to 1.5 on a scale of 100.
I too had my share of wraps and capture events using a threaded bridle.
Aero-towing uses a threaded bridle to this day. Sadly the back up on a three point attachment is also threaded. (My least favorite towing method for this primary reason.)
Pro-Tow to the two shoulder straps reduces the risk of a wrap and capture of a threaded bridle but increases the risk of being locked out over the top. (Not being able to keep the nose down due to high airspeed or a thermal.)
Pro-Tow I assume means you should be a professional if you decide to tow with this type of a bridle attachment .
Platform launching does away with unthreading and a possible capture event that is still to this day a concern while aero-towing. Platform launching only needs the towline to hook to the weak-link and then to the release at the pilots midsection.
The capture event is greatly reduced. The towlines angle from the platform tow vehicle greatly reduce the lock out over the top concern.
The second biggest reason I prefer PL to AT is that the glider is lifting off of a true tracking platform with PL as opposed to a meandering aero-tow, launch dolly or Ground Launch Vehicle (GLV) that sometimes takes you in your desired general direction. (After personal research I have come to the conclusion that there is little to no effect attenuating the meandrous path of an aero-tow launch dolly with the use of prayer alone.)
One might say forget the weaklink and release and just foot launch. When platform launching you need not commit to launching until you are well above stall speed.
Comparing that to the foot launch ramp I sometimes have to run to get past stall speed and find myself closer to the risk of a tip stall and more easily being turned back into the cliff or hill. Also if I sink out I most often can make multiple attempts PL towing whereas foot launching requires a longer turn around time between landing and launching again. It’s tough turning the wind direction or even the hill into the wind but towing into the wind with a platform tow launch vehicle is the easier of the three.
Foot launching into a crosswind is less safe than PL into a crosswind.
If a road or runway doesn’t line up with the wind you can effectively make the wind do it.
For instance if the wind is blowing 10 mph forty-five degrees from the left, when you start down the road or runway, by the time you are going 10 miles per hour you at this point have a effective cross wind angle of 22.5 degrees which is half of what you started with. I’ll let you do the math since you will be accelerating next to 20 mph. What now will be you relative crosswind direction?
But you are still going to accelerate another ten miles per hour to thirty miles per hour before you commit to launching. What now will be your effective crosswind direction?
The answer is, barely perceptible. Not even worth dragging out a pen and paper or calculator to do the math.
I was thinking of taking a few of the pluses of PL towing from my post here and start a PL thread in the training manual section of the U.S. Hawks forum.
I think the best way would be to include some of the best ideas and procedures that I and other pilots have picked up from seeing other PL rigs from past experiences and combine them all into the most desirable PL rig.
Features that come to mind that I see as worthy of a great PL rig are:
1) Nose over padded stop. (So that the glider cannot nose over and cause damage to the glider or winch operator or anything else for that matter.)
2) Base tube safety pins that keeps the base tube securely fixed into the launching yokes. (Safety pins that pull out from over each side of the base tube that are fast to either push in or pull out.)
3) Adjustable line tension, “on the fly” for the winch/reel. (Not a tension that you are stuck with until just before the next flight.)
4) A nose release actuator for the PL rig that will allow pilots to either hold their body forward or rearward with both hands and not require them to let go of the base tube and underlying hand holds to release the nose of the hang glider.
Hand holds under each side of the base tube so that premature lift off is not possible. (Tangle free hand holds designed to not snag any lines, cords, or wires.)
5) Airspeed indicator visible to both driver and pilot.
6) Constant transmit capability for the pilot while under tow. (Pilot in command - Not for students.) (TX must be clear with no air noise.)
7) Checklist waterproofed and on the PL rig right in front of the pilots face. (A duplicate checklist in view of the driver. Pilot goes through the checklist over the radio while the driver makes sure nothing is skipped.)
8) Level wind on the winch/reel for line retrieval.
9) PL rig designed to allow the pilots to load their gliders onto the launching platform while already hooked into the hang strap. (This would be a big time saver if many pilots were in a ready, queue, line waiting on the same platform tow rig.)
10) Safe seating for the winch operator and or observer.
What am I overlooking here? Any input that would make a PL rig the best that it could be?
I don’t know how one would go about doing it but another desirable feature would be some idea that could, to the extent possible, standardize the length of the nose release cord on each glider so that it would be the correct length on various platform tow rigs. If this is not possible then a design idea for platform rigs that would allow for a VERY QUICK adjustment for different sizes and models of hang gliders. What has been the best solution for this concern that you have seen so far? Anyone?
