US Hawks Hang Gliding Association

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?

billcummings wrote:Platform Launching (PL)
“We are done with this threaded bridle BS!”

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?

Bill,

Yeah, enough of that threaded BS

Maybe if each glider had a 6in. rope/ loop at the nose. Have release ropes made up in different lengths with a sewn loop in both ends. Kinda like hang straps.

Connect the correct length release rope to the nose loop with a wrap and back thru the loop. The loop in the other end would be at the release.

At least there wouldn't be any knots to attempt to untie.

I've seen the winch driver/operator get huffy if asked to adjust the rope length when first towing on a new winch.

This need for quick adjustments might occur most when towing on a new/unfamiliar winch.

Great topic, Bill.

Great idea Sam,
A length of rope or cord with a loop sewn at each end. Cords of varying lengths to be selected from depending on which platform rig is being used.

My nose rope has been dangling in place on my sport 2 since 2004 and even though I preflight everything each flight I’m still unable to recall if my nose cord goes just around the keel or around the keel ahead of the kingpost to nose cable. (To keep it from sliding rearward). (?????)
I remember rigging it so that it would stay in place and always lined up with the opening on the lower side of the nose cone where the tang on the front wires attach at the nose plate.

Next I’m thinking, at what varying length increments would be the best when making up the different cord lengths. Would ½ inch or one inch lengths from the keel be the way to go?

Oh Geez! My brain just went to mush when I got to the math part.
If we were sewing up cords that would be different by one inch from the keel incrementally and since it’s going around the keel would laying out each cord length measurement have to be increased by multiplying the diameter of the keel by 3.14159 to give us the next whole inch from the keel? (I need an Advil.)

How about I mail you the cord and the thread and you make them?
EDIT: Or would one just add two more inches to the overall cord length and sew the same size loop?

Bill,

You can rig your own nose rope on your glider, just leave it extending out ~6in., with a loop in it. That way it won't be dangling if you were not towing.

2 inch increments might be good to make the nose links.

I should be able to draw you a picture, but

Sam,
Now that I think about it, two inch increments on the nose release rope/cord would make small differences in the pitch once I considered how far away the pivot axis would be from the nose plate. Two inches makes more sense than ½” or 1” increments.

The nose release rope/cord that I have been using actually has two loops.
The bottom one that allows the glider to launch and the upper loop for when you are nowhere close to launching and is used only for what we call the, “Cold Nose Safety.”

Once we travel to the run up area of the taxiway, we remove the Cold Nose Safety and do the checklist, take up slack in the towline, and set the winch/reel brake pressure. At the end of the checklist, we read out loud (over the radio), “Nose Is Hot!” (Meaning, of course, that the Cold Nose Safety has been removed and the only thing holding the nose is the launch release.

Next, we are ready to taxi from the run-up area to the runway while announcing over the airport frequency our intension to take off on whatever numbered runway. At this point, the base tube safeties have not been pulled out, yet, since we may encounter crosswinds/thermal before turning into the wind on the active runway.

The command to proceed down the runway for take off MUST sound like this: (for us):
“BAR SAFETIES ARE OUT! GO TO CRUISE!” At this point, I must say that I am not a fan of using the command, “GO TO CRUISE AND ACCELERATE!”
Why? Because I’ve done it myself and I have seen it done as a PL driver and also observed it happening on Youtube; a pilot fumbling the release and having to try a second and third time to release. If your procedure is to accelerate once you have achieved your ideal launching airspeed, and you release late, now you will have more speed than your ideal launch speed. Too much speed, with some gliders, can start the adverse yaw and rolling. Also with higher airspeed, due to over coming the inertia of getting the winch/reel rolling, the weak link can pop.

At my local airport, 4,454’ msl and my approx 6,000’ average density altitude, 32 mph is the ideal airspeed for launching my all-up weight using a hang glider of 155sq. feet of sail area. This airspeed will be enough in the event of a weak link break, line-break, or a premature release one foot off the platform. It is enough airspeed to launch, round-off the climb, and favor either side of the runway or land directly behind the tow vehicle. With the tow vehicle maintaining 32 mph, and with the glider ascending at 45 degree angle, no way is the glider going to catch the tow vehicle, even if the glider wasn’t loosing airspeed, which it is. I see accelerating beyond ideal launch speed not to be a good idea because the winch may, for many different reasons, bind up or even “nest”, and not pay-out line. If this were to happen, and you launched late, at a higher airspeed, maintaining control behind the tow vehicle will be less likely. At this point, I would pump the bar out enough to break the weak link, round-off and land. This assumes that my weak link is no more than 1.6 of my all-up weight…in my case, no more than a 350 lb breaking strength.

My platform launch speed of 32 mph also allows for a hydraulic failure of the winch/reel brake. I will be able to launch, round-off the climb, release, get upright and land. A slower launch speed will not give me enough time or clearance to land safely. A faster launch speed starts crowding the too fast and over controlling edge of the operational safety envelope.

I’ll back up a bit to say, if a pilot would forget to pull out the bar safeties, from over each side of the base tube, and the driver also did not follow procedure and started down the runway without hearing, “Bar Safeties Are Out! Go to Cruise!”, there would still be no risk to the pilot or glider.

Once the nose release was activated, the glider would lift off the launching yokes and be stopped from lifting further than a quarter of an inch by the forgotten bar safeties. The glider would be flying safely, captured within the launching yokes. The glider would be unable to leave the launch vehicle. At this point it would be the worst mistake to try and remove the bar safeties. Successfully pulling out only one bar safety would be disastrous. The pilot must tell the driver to stop and then get a hand hold on the launch platform so that the tail of the hang glider does not drop and drag on the runway as the vehicle slows to a stop.

Bill,

That is a proven procedure sounds like.

The fact that just about every winch is different makes it difficult to write guidelines that will satisfy all of the models.

I'm thinking of raising my nose release on the payout rig in the back of my truck. At this time the nose rope pulling down on the keel.

Will relocating/raising the nose release effect the launch characteristics?

Sam,
King post-less gliders (KPL) should have the release inline with the keel so as not to be pulling down. That is not a concern with gliders that have a king post.

Raising the release could effect the launch characteristics depending on the length of the gliders nose release cord and whether or not the release is somewhat in front of the nose plate.

It has been my observation that most platform rigs like to set the pitch of the glider several degrees positive. I prefer to set the glider to be neutral at my 32 mph launch speed. The way to find that is to adjust the nose angle so that the base tube just about wants to lift off of the yokes at 32 mph without a pilot hooked into the glider. The base tube will be rattling between the bottom of the yokes and the over the bar safeties.
While doing this I keep the “Nose Cold Safety” hooked incase the release is accidentally tripped. Of course with the bar safeties in place the glider will not leave or be damaged even if the release were to be accidentally tripped.

At 32 mph and set at neutral the luff lines are in play working against the nose release cord.
If I were to raise the release and have it out in front of the nose with a 6” of nose cord hanging from the keel I would expect the base tube to lift out of the launching yokes and stop at the bar safeties. (with no pilot)
The way I rig on a PL it would change the launch characteristics.

If the release is raised and not in front of the nose I would not expect any difference. It would be like having a shorter nose cord than 6”.

Hi Bill and Sam,
Really good stuff here. I hope you do not mind, but I am sending some of your stuff to our local group to aid in our discussions of the same topic. We are in discussions here at AFFA concerning the future use of our winch. It could use a larger trailer. It is set up for foot launch HG and PG. It also does well used in conjunction with an AT dolly (all due deference to your opinion of the contraptions as only a regular PT harness is used). It is not set up for pure platform launch as the trailer is too small to accommodate.

Many of us, particularly old schoolers, want to put the winch on a new and larger trailer set-up for platform launch. Part of the proposed lay out for maximizing tows involves mounting the gliders on the trailer at the pilots lounge area. This is about mid way down the runway/taxiway. As each tow is completed, the tow vehicle would stop and get the next glider at the set up area and head on down to the end of the runway. The question concerns the safety aspects of ferrying an assembled hang glider. We have had two cases here where maneuvering assembled hang gliders has caused nose wire releases resulting in serious injury to both of the pilots. Can this be done safely?

Thanks,

Charlie Schneider

Charlie,
Yes you can transport safely from the pilots lounge midway on the taxiway.
Here are some suggestions for doing it safely.
First of all every PL rig should have a padded nose over stop so that the nose cannot come down and hurt someone or even the glider.
If you are transporting downwind to the beginning of the runway and there is a significant tail wind once the PL rig stops the tailwind can push the nose forward and down. That’s where damage and injury can occur.

Even parked headed into the wind a thermal can break off in front of the PL rig and create a temporary tail wind and cause the tail to raise which lowers the nose of the hang glider if there is no nose over stop. If some emergency stopping of the PL rig should arise the glider yet again can tip nose down due to inertia alone without a nose over stop.

A padded nose over stop alone is not enough. I recommend base tube safety pins, like ¼ inch stainless steel welding rods (flux removed) that can be pushed in a hole at the back of the base tube PL launching yoke, over the base tube, and on out through the front of the base tube yoke. One bar safety pin for each side of the base tubes’ two yokes. On the PL rigs that I have used we bent one end of the welding rod end in a curved “U” shape as a finger catch to pull the pins out.

I also put some light weight weaklink line at the finger catch that would let the pins dangle once pulled out. (Real weak incase something from the glider or pilots harness should snag the safety pin. If snagged the pin would break loose and go with the pilot.
I put ever so slightly a bend in the safety pins so that they would slightly bind in the yoke holes and not jiggle out but only come out once pulled.

Attach a second cord to the nose of the glider that has to be manually removed at the “run-up,” area. (Warm up area at the start of the runway.) This second nose cord or line is called the “Cold Nose Safety.” If you accidentally trip the main nose release between the Pilots Lounge and the run-up area you will still have the nose held by the “Cold Nose safety.”

Using the bar safeties, nose over stop, and cold nose safety the glider is securely fastened to the PL rig for any event.

At the run-up area park crossways to the wind at least, do the check list which will include removing the cold nose safety so only the nose release for launching is holding the nose of the hang glider, announce your intention to enter the runway for take off, and finally when turning to line up with the runway into the wind pull out the bar safeties and say over the USHPA radio, “BAR SAFETIES ARE OUT! -GO TO CRUISE!”

Hand holds under the base tube are a must for when the bar safeties are out in case a thermal should try to lift out one side before you have achieved launching speed.

Even safer than that is hook the pilot in at the run-up area.

billcummings wrote:Even safer than that is hook the pilot in at the run-up area.

Take that T*d.