.

.

All things hang gliding. This is the main forum. New users, introduce yourself.

Moderators: sg, mods

#402578
There was a big discussion (argument) in a previous thread about whether a glider could be steered (put into a roll) without contact to the control bar. I agreed with Ryan V, but didn't join in because it was getting ugly, and I would rather show than talk about it.

I looped a small piece of climbing rope to the hang strap, floated my Condor 330 up in the air, then could initiate roll completely from the hang strap.

#402580
You can pull it left or right but you cannot control pitch or roll.
#402581
Assuming there's enough anhedral (negative dihedral) then pulling the glider to the side so that there is a skid, or slip, the glider should bank into the leading wing.

If the glider has dihedral then it would tend to roll away from the leading wing. I believe that the Condor does have enough anhedral, or "anhedral effect" , to make it responsive in roll, a good idea on the training hill.

But what makes it respond well in roll may also be why high altitude flying is prohibited. Too much anhedral and you won't be able to roll out of a turn.

In 1979 I almost bought the farm when I went too far with tensioning the lower deflexor cable on my Seagull 10 Meter. I was ready to toss my 'chute, but was contemplating just where those big power lines were relative to me and the wind direction. It would be a real pisser to have a life saving parachute drift me into a high voltage scene. But she finally gave in and let me roll out, after at least a half-dozen 360's with me as far high-sided as was anatomically possible. My muscles ached for a week, damn adrenaline saved the day.

I lengthened the side wires to fix it, rather than give up my cylinder. Once she was properly tuned she would climb like a homesick angel, and wingovers were dramatic. I miss the old gal, may she R.I.P.
#402588
Tormod wrote:
Thu Mar 08, 2018 11:47 am
EricH wrote:
Thu Mar 08, 2018 11:17 am
Tormod wrote:
Thu Mar 08, 2018 2:39 am
As long as your feet touch the ground, else there's no leverage.
or if it were attached to another aircraft?
How? And why would it be relevant?
Just trying to address the theory of some that you can't steer a weight shift aircraft just by shifting weight, that you somehow need to have another connection to the glider besides the hang strap.

Watch how I put the glider into a right turn in the air with no connection to anything besides the hang strap:
#402602
The point is that you can't shift the weight without something to hold on to. In the case of the video you yaw your body and the air pushes your body to the right and thereby shifting the weight to the right. There's no "somehow" to it, it's just physics. You can't move your CG with sheer will power.
#402621
EricH wrote:
Thu Mar 08, 2018 12:50 pm

Just trying to address the theory of some that you can't steer a weight shift aircraft just by shifting weight, that you somehow need to have another connection to the glider besides the hang strap.

Watch how I put the glider into a right turn in the air with no connection to anything besides the hang strap:
Not quite
by Lazypilot » Thu Mar 08, 2018 9:32 pm
Something is amiss here.
Exactly.

What Eric didn't account for in his last example is that the air currents are being driven upwards from the cliffs at an angle that is normal to the direction of the cliffs. While flying parallel to the cliffs, the glider's airspeed vector added to the vector of the air currents being thrust upward at an angle, create an apparent 'wind' to the ocean-side (starboard) wing that is at a higher angle of attack compared to the land-side (port) wing, due to the wing's sweep angle. The starboard wing of course experiences more lift, but more importantly, creates more drag than the port wing, therefor the glider yaws to starboard, and only continues past equilibrium of both wings' individual drags until the rotational momentum is damped. The pilot gave zero control input to the glider yawing even though his body was a bit skewed from the glider's initial heading. This happens a lot while slope soaring in a glass-off, does it not?!?!
#402634
While it's true that I'm a critic of the present Hg technology, I do recognize that it is forgiving of a poor understanding of aeronautical theory. Perhaps it should be left alone, too much freedom in the wrong hands might be dangerous. :popcorn:
#402637
Lazypilot wrote:
Sat Mar 10, 2018 2:11 pm
While it's true that I'm a critic of the present Hg technology, I do recognize that it is forgiving of a poor understanding of aeronautical theory. Perhaps it should be left alone, too much freedom in the wrong hands might be dangerous. :popcorn:
Awe.... you're just being PC now. Tell us what you really think is happening in the previous example. :popcorn: :popcorn: :popcorn: :popcorn: :popcorn: :popcorn: :popcorn: :popcorn: :popcorn: :popcorn:

:P
#402647
I was having a nice glass of red wine when I wrote this late the other evening, and left out some essential details.
DMarley wrote:
Fri Mar 09, 2018 11:37 pm

What Eric didn't account for in his last example is that the air currents are being driven upwards from the cliffs at an angle that is normal to the direction of the cliffs. While flying parallel to the cliffs, the glider's airspeed vector added to the vector of the air currents being thrust upward at an angle, create an apparent 'wind' to the ocean-side (starboard) wing that is at a higher angle of attack compared to the land-side (port) wing, due to the wing's sweep angle. The starboard wing of course experiences more lift, but more importantly, creates more drag than the port wing, therefor the glider yaws to starboard, and only continues past equilibrium of both wings' individual drags until the rotational momentum is damped. The pilot gave zero control input to the glider yawing even though his body was a bit skewed from the glider's initial heading. This happens a lot while slope soaring in a glass-off, does it not?!?!


The only time this situation could occur is if there was an airspeed reduction of the glider, and/or change in direction and/or magnitude of the air currents.
The angle of attack is not really different on both wings, rather it's the flow direction relative to each wing's sweep angle that changes between the two. I.e., if the glider slows it's airspeed down to trim and the air current is flowing from ocean to land at an upward angle, the resultant apparent wind to the wings will appear to clock around to the ocean side by a small amount, something similar to landing in a crosswind. The difference in drag of both wings results from the clocking airflow, causing the apparent flow to encounter a longer effective span on the starboard wing, and a shorter effective span on the port. Thereby the starboard wing generates slightly more lift, but also more drag compared to the port wing.
When the pilot in the vid example releases control of the control bar, he likely is allowing the glider to slow to trim from a slightly higher airspeed. Either that or he is flying into a section of air current that has a slightly higher velocity. Or both.
That's my theory.
What's yours?
:popcorn:
User avatar
By NMERider
#402657
EricH wrote:
Thu Mar 08, 2018 12:50 pm
....Watch how I put the glider into a right turn in the air with no connection to anything besides the hang strap.....
And you failed to stop the glider from turning right by merely wiggling your body. Instead you grabbed the bar the end the turn. In other words you have very little or no control over the glider without holding on to the control frame.

Here's another thing. When running with the glider and only connected by the hang loop, the glider becomes a single-line kite. The physics involved in single-line kite stability and control is extremely complex. There are a number of scientific engineering studies published. The degree of control invoked by running from side to side is extremely limited and in many cases the control is actually reversed and the kited glider will roll and yaw in the opposite direction and crash.

The useful aspect of this entire subject is that pilots need to learn to fly their gliders while they are doing a running launch or a running landing. Not enough pilots have developed the skill of controlling their glider while running--whether it's launching or landing. The best control is achieved by holding on to the control frame and exerting torque into the glider's different axis using some combination of weight-shift and thrust via lateral, rotational or propulsive/resistive force transmitted from the feet through the trunk of the body.
#402669
EricH wrote:
Thu Mar 08, 2018 12:50 pm
Tormod wrote:
Thu Mar 08, 2018 11:47 am
EricH wrote:
Thu Mar 08, 2018 11:17 am
Tormod wrote:
Thu Mar 08, 2018 2:39 am
As long as your feet touch the ground, else there's no leverage.
or if it were attached to another aircraft?
How? And why would it be relevant?
Just trying to address the theory of some that you can't steer a weight shift aircraft just by shifting weight, that you somehow need to have another connection to the glider besides the hang strap.

Watch how I put the glider into a right turn in the air with no connection to anything besides the hang strap:
I can tune out that right turn for you when your ready to accept it has a right turn in it.
User avatar
By EricH
#402754
NMERider wrote:
Sun Mar 11, 2018 5:36 pm
In other words you have very little or no control over the glider without holding on to the control frame.

Here's another thing. When running with the glider and only connected by the hang loop, the glider becomes a single-line kite. The physics involved in single-line kite stability and control is extremely complex. There are a number of scientific engineering studies published. The degree of control invoked by running from side to side is extremely limited and in many cases the control is actually reversed and the kited glider will roll and yaw in the opposite direction and crash.

The useful aspect of this entire subject is that pilots need to learn to fly their gliders while they are doing a running launch or a running landing. Not enough pilots have developed the skill of controlling their glider while running--whether it's launching or landing. The best control is achieved by holding on to the control frame and exerting torque into the glider's different axis using some combination of weight-shift and thrust via lateral, rotational or propulsive/resistive force transmitted from the feet through the trunk of the body.
I never claimed full control, thanks for acknowledging that there is control NME and Tormod, that puts you on my side vs. those that say there is no control.

Everyone talks about having as many tools as possible in their tool box, yes, leveraging off the control frame to shift weight gives us more control, but if you can combine your run and leverage your weight with your feet as you also do with your hands, isn't that an advantage?
User avatar
By NMERider
#402757
EricH wrote:
Sat Mar 17, 2018 11:19 am
....Everyone talks about having as many tools as possible in their tool box, yes, leveraging off the control frame to shift weight gives us more control, but if you can combine your run and leverage your weight with your feet as you also do with your hands, isn't that an advantage?
Running with good tension on the hang strap and feet on the ground yields maximum lateral control whether launching or landing. It's a good skill for pilots to practice. It probably would not hurt to practice kiting a single surface glider by running with it and not touching the control frame while trying to make it track.

Thanks for the replies. Yes, it's really a beatifu[…]

Subaxtreme got back to me with good information. […]

La Muela de Alarilla, Spain

Cool place, nice edit! Thanks! I saw in GoogleMa[…]

Going to see Bent Knee 6 July 18. Courtney Swain, […]