[Bob Kuczewski]

Bob radio's: "Bill, my remote batteries just died, down here, and I know you're busy up there, working that thermal, --but -- could you fire up your remote again and I'll talk you in to land the drone?"

Words of wisdom from someone who knows Murphy's law all too well.       

[reluctantsparrow]

That was interesting Joe.....the skyhook.....wow...would love to experience that at least once. The part about the pig was awesome....what? they snatch a pig off the ground and did not expect him to get pissed?......a pig has the same IQ as a four year old child.....they should have picked on a less intelligent animal.
I have been thinking a bit more about the spiral towing idea and I hate to point this out on a forum for hang gliders only.....but....with the pendular stability of a paraglider and the relativly equal performance most paragliders possess I see the spiral tow technique working like a charm for paragliders except where would they carry the onboard winch which would have to be very small and lightweight? Maybe inside their BAT-BELT? Hahahahaha
I think it will work for three axis machines the best.

[Bob Kuczewski]

I have been thinking a bit more about the spiral towing idea and I hate to point this out on a forum for hang gliders only.....but....with the pendular stability of a paraglider and the relativly equal performance most paragliders possess I see the spiral tow technique working like a charm for paragliders except where would they carry the onboard winch which would have to be very small and lightweight?

No winch needed. They could rig up a recumbent bicycle pedalling system!!   

By the way, your safe splat video was super!!   

[reluctantsparrow]

No winch needed. They could rig up a recumbent bicycle pedaling system!!   

No, Bob, I dont think they could, but....

WE can!!!!!
(now why didnt I think of that?)
Are you really this brilliant or were you just joking?
because...yes...we actually can.....here are the average bicycle speeds

From wikipedia; Typical speeds
In utility cycling there is a large variation; an elderly person on an upright roadster might do less than 10 km/h (6.2 mph) while a fitter or younger person could easily do twice that on the same bicycle. For cyclists in Copenhagen, the average cycling speed is 15.5 km/h (9.6 mph).[10]
On a racing bicycle, a reasonably fit rider can ride at 40 km/h (25 mph) on flat ground for short periods.[6]

You got that? a reasonably fit rider can ride at 25 Mph..(plenty of airspeed)....and since every ounce of energy produced by the buddy tow system goes directly into creating speed for one glider or the other....Two people doing a buddy tow....each of them in a special trike style configuration (made very light like a bicycle).... COULD bicycle each other up into the AIR!!!!!!
Since they are pedaling towards each other and connected it would not require any more energy than pedaling a bicycle except for the drag factor of the glider.....the additional drag.....that is the only obstacle....could a reasonably fit person pedal at 25 mph with a large wing overhead? okay...maybe we cant do it....but HOly COW!!! awesome idea!
This would be far more doable than the Paul macready/brian porter machines since we are NOT wasting all the energy it takes for a propeller to beat the air into submission.
No, we are towing directly off of each other, not thrashing the air, and every ounce of pedal power is translated directly into airspeed.
And yes, it would indeed be a recumbant and the front wheel could double as the winch itself.....RS

[KaiMartin]

WE can!!!!!

Well, we cannot.
Not with a machine that resembles a regular glider.
Not unless the pilot can deliver superman worth levels of power.
Let me elaborate:
Minimum sink of modern hang glider is somewhere around 0.7 metres per second.
The combined weight of pilot and wing can be assumed to be an optimistic m = 100 kg.
Every second the glider sinks by h = 0.7 m it gains potential energy E:
E = m * g * h
= 100 kg * 9.81 m/s^2 * 0.7 m
= 687 W.
Where g = 9.81 m/s^2 is the acceleration by gravity fairly close to ground.
While sinking by 0.7 m/s the glider converts 687 Ws (Watt-seconds) worth of gravitational energy into eddies, vortices and general air friction. Any drive which is to keep the glider at the same height has to compensate this constant loss of energy. (Excuse me for using metric values. You probably get the idea despite unfamiliar units)
Now, how much power can a pilot reasonably deliver? Fortunately, bicycle racers have been thoroughly tested and measured. A decent, well trained amateur racer can achieve about 5 W per kg body weight for about half an hour. For the estimation above, the pilot was assumed to weigh in at 70 kg. So he has about 350 W to spend.

To a certain extent the pilot may deliver more power for a shorter time. He might be able to hit 687 W for a few minutes. But this only prevents him from descending. If he wanted to rise by a meagre 0.7 m/s he'd have to deliver double the power. This would be a power level even Tour de France champions would have trouble to achieve. Bicycle riders easily exceed minimum speed of hang gliders because they happen to not drag 14 m² of wings through the air (duh...)

If power considerations for hang gliders look bleak like calculated above, how come people have often been videoed pulling a glider by hand? The answer is "wind". A steady wind reduces the speed needed with respect to ground. Meanwhile, the pulling force required to keep the glider aloft stays the same. The same force at reduced speed means reduced power requirements for the pull. If the wind exceeds the minimum speed of the glider it can be kited with no power at all.

Unfortunately, no reasonable wind pattern can help with the mutual, circular winch scenario. (Ring-a-ring o' roses around the centre of a dust devil, anyone?) So we are essentially left with the option to use motors to deliver the level of power that actually stands a chance to lift the hang gliders from the ground.

---<)kaimartin(>---

[reluctantsparrow]

Okay Kai, Thanks....so how about this application?....build a lightweight recumbant trike with a winch on the front, play out a couple grand of line, and wait for the wind to blow (we do that anyway)
how much wind would be required?
the anchor end of the line would be on a slip ring that slides off the anchor once i peddle past the anchor point, at which point I keep peddling and reel in the tow line.
with a 10 mph wind to winch into could I peddle my a** up into the sky, winch in the remaining line, and go looking for lift?
I am not good at math, I barely made it through high school, I only have an endless stream of ideas.....so...
could this be done and how much prevailing wind would be required?
I really want to do this....RS

[JoeF]

RS, for the pedal-powered winching, Kai left open a door for non-common hang gliders (think towards Gossamer Condor technology or exotic high L/D wings and probably hidden streamlined pilot pod). "Not with a machine that resembles a regular glider" That leaves open the space of non-regular gliders. Under tension the "gliders" are kited wings; upon slack and/or release the wings become gliders.
==================================

Bill Watson (master intuitive model-flight expert) and I talked at Otto #45. He suggested he may do some model tests on some first-level two-glider arrangements using only rubber band thin tether for the Bungee Leap portion, not the slack and re-do. The 100-HG-spoked method or perimeter-test method will be done after mastery of the low-wing count arrangements occurs

Filler: See one of the hundreds of Bill Watson mentions: 1985

===================================

[eagle]

Gabriel Poulain on his record-setting run.
Earned him the Peugeot Prize for human-powered flight on July 9, 1921. (Source: Flugsport, Aug. 17, 1921)
See News: http://generalaviationnews.com/2011/04/ ... g-bicycle/

Launching.jpg (45.05 KiB) Viewed 4653 times

[reluctantsparrow]

pretty creative guy this Watson (his name made me think of Sherlock Holmes saying.... elementary, my dear Watson...)
I live near Dog Mtn. in washington state. There is a huge, wide open LZ right at the base and a lower bluff that is usually the first section to become soarable each day as the wind fills in on the Riffe lake.
I am tired of Paying through the nose for permission to drive up this mountain each year.
When the wind starts to fill in conditions are usually quite smooth in the LZ.
I am going to build a recumbant trike with a winch up front where I can peddle up off the beach into a smooth 15 mph wind, release, glide to the lower bluff, and soar to my hearts content with no gas, no oil, no battery, etc....nothing but my own two legs.
Remember the self soar society Joe? That is really my primary incentive for wanting to fly in the first place, to self soar.
My primary gripe about the direction Hang Gliding has gone is the loss of what I call the freedom factor.
Add enough regulation, enough gates that require keys and fees, enough rules like you cant fly here unless your insured, and the freedom factor drops so low I would rather go for a walk than go fly because the freedom factor becomes higher going for a walk.
I am going to build the device I have in mind to pluck the self soar experience I dreamed about growing up....RS

[Bill Cummings]

RS,
It can work.
Like I've said/typed before, I've rope soared (kited) behind stopped snowmobiles, stopped cars, stopped boats, and stopped wife on the beach. When the wind died a little my buddy kept me from sinking out while trudging back to the snowmachine with the rope over his shoulder. If on the other hand he couldn't trudge back and I had the ability to peddle in some rope (with the winds help) I could gain altitude. Cutting right or left of an anchor point kind of cracks the whip like a water skier does when cutting left or right of the boat.
Anchored, with a wind, that is enough. Add an incline that is more than enough, depending on the wind speed and incline. To make it work with less of either compensate with a peddle rope system.
How about this at Dog Mt. Peddle crank tension onto a bungee line first to pre-tension (peddle battery) then once you release the bungee add to the stored tension by peddling.
Peddling through dead air on the flat --- I'm not even going to try that without a bungee.