Any PG pilots thinking of going out to Woodstock on Wednesday?
Matthew
Woodstock Wed?
Moderator: CHGPA BOD
To elaborate on my PG flight at Woodstock yesterday: in contrast to Matthew's, mine was rather short (15 minutes). This was the strongest wind (19 at altitude, less on launch) I had successfully launched in and I was apprehensive about penetrating, so stood on the speed bar to remain low and get out front. Overachieved and ended up below launch and sinking. Good experience though - next time I'll be more willing to experiment with climbing while monitoring penetration. Is there such a thing as steering with differential speed bar left-right, or is that a recipe for partial collapse? - Hugh
PS - Ozone Buzz seemed rock solid on speed bar - I'm loving this as a P2 wing and maybe longer.
PS - Ozone Buzz seemed rock solid on speed bar - I'm loving this as a P2 wing and maybe longer.
Speed Bar Steering
Never heard of speed bar steering. You can still weight shift and usue a little left and right brake with speed bar. To find you speed bar and get extra speed at the same time, lean forward in your harness. This puts a little extra pressure on the A's for speed. And the speed bar will then fall directly against the back of your legs, being easier to catch with a foot.
Matthew
Matthew
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Marcel Dettling
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Sorry Matthew, but touching the brakes while on bar is a big (very big!) no-no. Much bigger risk of suffering a collapse because if you apply brake, more lift is produced in the rear part of the wing. The angle of attack is low anyways while on bar, applying brake takes pressure from the leading edge: in this configuration you are very much prone to take deflations.
Next is, leaning forward doesn't help to gain speed. More pressure on the A's? Forget it, leaning forward does affect all the risers. By leaning forward, you just increase pilot drag, what makes you going slower (at least sinking faster, though).
Hugh, there is nothing wrong with speed bar steering. Weight shifting is also good. Just make sure you can release the bar quickly if the wing collapses. Recovery is a lot less benign if you don't release it.
Cheers,
Marcel
Next is, leaning forward doesn't help to gain speed. More pressure on the A's? Forget it, leaning forward does affect all the risers. By leaning forward, you just increase pilot drag, what makes you going slower (at least sinking faster, though).
Hugh, there is nothing wrong with speed bar steering. Weight shifting is also good. Just make sure you can release the bar quickly if the wing collapses. Recovery is a lot less benign if you don't release it.
Cheers,
Marcel
Brakes and Spped Bar
I'm not talking about a lot of brake... just a little. And you have obviously never seen Mickey fly in strong winds effectively using both brakes and speed bar. As to leaning forward, it does apply pressure to the A's and surge the wing forward. Try it sometime. Or try in when kiting. Let the wing fall behind you when facing forward...and then lean forward, the wing will surge back overhead.
It does it every time.
Matthew
It does it every time.
Matthew
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Marcel Dettling
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- Joined: Thu Aug 11, 2005 1:00 pm
- Location: Zurich (Switzerland)
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Even a little brake is too much while on bar. I don't know what Mickey does. But just because he does "it", it doesn't mean it's safe. Talk to any PG designer, or go and read other forums, it has been discussed many times. As to flying "effectively" in strong winds with speed bar and brake, that's an oxymoron. Either you wanna go fast, so you apply speed bar, or you wanna stabilize the wing, so you apply brake (and go off the bar). Again, both together does not work.
On a side note, Chrigel (he's often flying his prototype with a lot of bar at 65kmh through turbulence) even wears shoes that he modified with a file, so that he can let the bar (it's actually only a piece of webbing in the Impress) slip as quickly as possible. So if he feels the wing surge and/or a collapse coming, he lets it slip and applies 100% brake a milisecond thereafter. He himself swings forward and all this causes such an increase in the angle of attack on the wing, that virtually every collapse on bar can be prevented. But it requires years of experience to train the reflexes for safely flying so fast, and still big balls.
As to leaning forward. The sensation you describe on the ground (wing comes back overhead when you lean forward) has nothing to do with "putting more pressure on the A's". If you lean forward from standing upright, the attachment point (of the risers) is a) moved down and b) moved forward. That's what makes the wing come back overhead. Once in the air, the wing doesn't care the least bit if you lean forward or not. How should it, there is a central attachment point where all risers go to, so you don't have any special effect on the A's.
Sorry, with such dangerous actions (speedbar&brake) and aerodynamical knowledge (leaning forward), you wouldn't even get a pilots license here. Neither could you be an observer (though we don't have that bulls*** system here), it's just plain dangerous.
Marcel
On a side note, Chrigel (he's often flying his prototype with a lot of bar at 65kmh through turbulence) even wears shoes that he modified with a file, so that he can let the bar (it's actually only a piece of webbing in the Impress) slip as quickly as possible. So if he feels the wing surge and/or a collapse coming, he lets it slip and applies 100% brake a milisecond thereafter. He himself swings forward and all this causes such an increase in the angle of attack on the wing, that virtually every collapse on bar can be prevented. But it requires years of experience to train the reflexes for safely flying so fast, and still big balls.
As to leaning forward. The sensation you describe on the ground (wing comes back overhead when you lean forward) has nothing to do with "putting more pressure on the A's". If you lean forward from standing upright, the attachment point (of the risers) is a) moved down and b) moved forward. That's what makes the wing come back overhead. Once in the air, the wing doesn't care the least bit if you lean forward or not. How should it, there is a central attachment point where all risers go to, so you don't have any special effect on the A's.
Sorry, with such dangerous actions (speedbar&brake) and aerodynamical knowledge (leaning forward), you wouldn't even get a pilots license here. Neither could you be an observer (though we don't have that bulls*** system here), it's just plain dangerous.
Marcel
Speedbar and Brake
As to leaning forward, this presses the shoulder straps against the risers. The risers are in layers with the A's in the front. When you rock forward pressing your shoulders against the risers IN THE AIR, the risers in the front receive a greater amount of force and there is a differential pressure on the lines with the A's receiving more pressure, thus plling on the A's and pulling the nose over slightly to create more speed. I've done this IN THE AIR many times and it has worked every single time. By your argument that the pilot is just swinging around with no input to the wing, weight control wouldn't work.
As to speedbar and brake, show me some evidence of why this is dangerous. There are various degrees of speedbar use. The speedbar pulls the leading edge of the glider forward and down to create speed. It does not destoy the shape of the wing unless you have so much speedbar that you lose inflation. The brakes work like flaps, pulling down portions of the trailing edge of the wing. If the wing is fully inflated then the use of the brakes has no adverse effect. Even with speedbar, the glider can surge forward or have small turns, how do small inputs to the brakes in any way hurt the wing when it is fully inflated and stable. Conversely, pulling BIG EARS destroys a large section of the wing. But what are we taught to do when using BIG EARS? We are taught to add a little speedbar to overcome the drag from the ears. So what is the rationale for using speedbar and BIG EARS together but not speedbar and brakes together? Again, I have done speedbar with small brake inputs with no adverse affect and have seen it done on a much more extreme level with no adverse affect. Is there any empirical evidence showing the dangers of using any speedbar and brake combination. Remember, speedbar is not a full on or off thing. There are degrees of speedbar use. Have you ever tried brakes with speedbar?
Matthew
As to speedbar and brake, show me some evidence of why this is dangerous. There are various degrees of speedbar use. The speedbar pulls the leading edge of the glider forward and down to create speed. It does not destoy the shape of the wing unless you have so much speedbar that you lose inflation. The brakes work like flaps, pulling down portions of the trailing edge of the wing. If the wing is fully inflated then the use of the brakes has no adverse effect. Even with speedbar, the glider can surge forward or have small turns, how do small inputs to the brakes in any way hurt the wing when it is fully inflated and stable. Conversely, pulling BIG EARS destroys a large section of the wing. But what are we taught to do when using BIG EARS? We are taught to add a little speedbar to overcome the drag from the ears. So what is the rationale for using speedbar and BIG EARS together but not speedbar and brakes together? Again, I have done speedbar with small brake inputs with no adverse affect and have seen it done on a much more extreme level with no adverse affect. Is there any empirical evidence showing the dangers of using any speedbar and brake combination. Remember, speedbar is not a full on or off thing. There are degrees of speedbar use. Have you ever tried brakes with speedbar?
Matthew
Speedbar and Brakes
Hey, Guys i like the topic there is several opinions on that
One: is if you want to go fast why apply brakes usually you apply brakes on speedbar because it "make you feel more stable" but it does not, and like Marcel said if you don't control that you probably end up with a big collapse
Two: You can use brakes and speedbar, but you have to know what you are doing, The speedbar alone helps you change the angle of attack so you can play with that(with training)to gain stability even in a collapse just buy releasing the speedbar at the right time you can avoid a collapse.
It takes time to control your glider only with speedbar but it is a good thing for performance.
Try some time to fly speedbar and Brakes you will note the difference when you fly without brakes (be high).
Juanito
One: is if you want to go fast why apply brakes usually you apply brakes on speedbar because it "make you feel more stable" but it does not, and like Marcel said if you don't control that you probably end up with a big collapse
Two: You can use brakes and speedbar, but you have to know what you are doing, The speedbar alone helps you change the angle of attack so you can play with that(with training)to gain stability even in a collapse just buy releasing the speedbar at the right time you can avoid a collapse.
It takes time to control your glider only with speedbar but it is a good thing for performance.
Try some time to fly speedbar and Brakes you will note the difference when you fly without brakes (be high).
Juanito
Hi Juan
Hi Juan,
Where ya been.. besides kicking ass in the Nationals. Congrats!!!!
You should have come to the Pulpit on Sunday. We all had sleds. But I'm sure you would've gotten up and out of there. There were a couple of tight thermals. But I was too low and afraid of not making the LZ to feel comfortable circling in them. And the previous weekend at the Pulpit was stellar for PGs.
Looks blown out this weekend. Glad I took off to fly the last couple of days.
Matthew
Where ya been.. besides kicking ass in the Nationals. Congrats!!!!
You should have come to the Pulpit on Sunday. We all had sleds. But I'm sure you would've gotten up and out of there. There were a couple of tight thermals. But I was too low and afraid of not making the LZ to feel comfortable circling in them. And the previous weekend at the Pulpit was stellar for PGs.
Looks blown out this weekend. Glad I took off to fly the last couple of days.
Matthew
Hi Mathew,
I really wanted to go to Pulpit but conditions were not good we end up in Daniel's But it was coming from the back,should it go to Dickies.
The nats were great lots of fun and good flying, this weekend does not look so good so tennis or biking is in my agenda.
There is a Comp in owens valley oct 7,8,9 i'm going with Tom check it out is in the Forum Paragliding.
Let's see the weather during the week.
cheers
Juanito
I really wanted to go to Pulpit but conditions were not good we end up in Daniel's But it was coming from the back,should it go to Dickies.
The nats were great lots of fun and good flying, this weekend does not look so good so tennis or biking is in my agenda.
There is a Comp in owens valley oct 7,8,9 i'm going with Tom check it out is in the Forum Paragliding.
Let's see the weather during the week.
cheers
Juanito
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Marcel Dettling
- Posts: 93
- Joined: Thu Aug 11, 2005 1:00 pm
- Location: Zurich (Switzerland)
- Contact:
Re: Speedbar and Brake
I'm following up on that.
To the question whether standing upright in your harness increases your forward speed. The answer is no. For an explication, if you want it short, read this quote of Adrian Thomas. He's an aerodynamicist in academia and also works for Airwave:
A long, long discussion can be found at:
http://www.paraglidingforum.com/viewtopic.php?t=4049
There is one more big danger of standing upright. You don't release the bar in case of a collapse. And then even a usually laid back beginners wing can surge below the horizon.
Let me tell a scary story of a friend: he was on a long XC and eating some chocolate while on full bar during a transition, hands off the brakes. Despite seemingly calm air, he took a big deflation. Hands off the brakes, so he stayed on bar to get some hold while falling. It was a DHV 1-2 wing, which asymmetrically surged below his feet. He had the risers twisted and immediately was in a locked spiral. Good he had more than 5000ft of ground clearance, so he could set things straight again (untwist first and then stop the spiral). But he noticed that because of the riser twist, the sheating of some lines was burnt. He landed, very scared, with his reserve ready to throw on his lap.
What we learn from this: while being on bar, always, always focus on letting it go asa the wing collapses. I imagine it's a lot harder to do if you're standing.
Brake & bar application follows later.
Cheers,
Marcel
To the question whether standing upright in your harness increases your forward speed. The answer is no. For an explication, if you want it short, read this quote of Adrian Thomas. He's an aerodynamicist in academia and also works for Airwave:
And very closely related:Adrian Thomas wrote:Experimentally if I go from my fully-faired flight position to vertically upright (hands off the whole time) I get an increase in sink rate and a decrease in gps speed. The values are small - less than 0.5m/s increase in sink and around 2kmh speed. Potential errors are large, but the result is consistent, especially when I do it on glide at altitude.
So why do almost all comp pilots use faired harnesses, and why have I never seen one going upright in final glide to be faster?Adrian Thomas wrote:does a reduced-drag harness lead to faster flight speeds? The answer is, at any given trim angle of attack it does (more load on the wing, less taken by pilot drag). So at full speedbar you go faster with lower sink rate, which is why all the top PWC pilots have faired harnesses.
A long, long discussion can be found at:
http://www.paraglidingforum.com/viewtopic.php?t=4049
This argument is absolutely pointless. Please explain me the physics, why the A's should receive a greater amount of "pressure". You apply a force perpendicular to the lines, and it does affect all the lines in exactly the same manner. Only one thing is true. If you shorten the A's relative to the other lines, the wing will go faster. But this doesn't happen by leaning forward.Matthew wrote:As to leaning forward, this presses the shoulder straps against the risers. The risers are in layers with the A's in the front. When you rock forward pressing your shoulders against the risers IN THE AIR, the risers in the front receive a greater amount of force and there is a differential pressure on the lines with the A's receiving more pressure, thus plling on the A's and pulling the nose over slightly to create more speed. I've done this IN THE AIR many times and it has worked every single time. By your argument that the pilot is just swinging around with no input to the wing, weight control wouldn't work.
There is one more big danger of standing upright. You don't release the bar in case of a collapse. And then even a usually laid back beginners wing can surge below the horizon.
Let me tell a scary story of a friend: he was on a long XC and eating some chocolate while on full bar during a transition, hands off the brakes. Despite seemingly calm air, he took a big deflation. Hands off the brakes, so he stayed on bar to get some hold while falling. It was a DHV 1-2 wing, which asymmetrically surged below his feet. He had the risers twisted and immediately was in a locked spiral. Good he had more than 5000ft of ground clearance, so he could set things straight again (untwist first and then stop the spiral). But he noticed that because of the riser twist, the sheating of some lines was burnt. He landed, very scared, with his reserve ready to throw on his lap.
What we learn from this: while being on bar, always, always focus on letting it go asa the wing collapses. I imagine it's a lot harder to do if you're standing.
Brake & bar application follows later.
Cheers,
Marcel
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Marcel Dettling
- Posts: 93
- Joined: Thu Aug 11, 2005 1:00 pm
- Location: Zurich (Switzerland)
- Contact:
Re: Speedbar and Brake
I had written it above: the airfoil produces most of the lift near the leading edge. Applying brake whilst on bar makes the air foil produce more lift in the back section, which causesMatthew wrote:As to speedbar and brake, show me some evidence of why this is dangerous.
- less pressure on the leading edge -> less collapse resistance
- a forward pitching moment -> big collapse danger
There is a very interesting thread on the German forum with Hannes Papesh and Dani Loritz (both PG designers) giving the main input. My wisdom comes from there.
Also, there are some comp wings which (in still air!!!) can reproducibly be collapsed by applying just a few inches of brake while on bar. Lower rated wings usually have a little bigger tolerance to this. However, this doesn't mean you should apply brake and bar together, the risk of a collapse is also much higher there.
You can also read this, again from Adrian Thomas:
If you're not convinced go and make all the bad experiences yourselves. This was my last try to explain why speedbar and brake is a big no-no, and why standing upright doesn't increase speed.Adrian Thomas wrote:Go and look at your wing when you apply speedbar and brakes. Better still, fly alongside someone else and watch their wing distort as they apply speedbar and brakes. Horrid. On almost all wings when you apply the brakes the glider distorts forwards of the rear risers. At speed this distortion can travel forwards far enough to droop the nose.
Cheers,
Marcel
Speedbar and Brake
Hi Marcel,
I never said standing upright increases speed. I said the leaning forward into your shoulders straps increases speed a little and allows you to find your speedbar. I just watched a paragliding video and saw lots of people doing this. I'm gonna strap on my GPS next time and do some experiments in calm stable air leaning forward.
As to speedbar and brake. Again I never said to apply both brakes with speedbar, I said apply a little left and right brake to steer with speedbar. If you are doing regular coordinated turns with speedbar, I bet you are adding a little brake with your weight shift turn. This is inherent as your arm follows your body when you lean into the turn, applying a little brake. Unless you are deliberately go hands off, I bet you are applying a little brake in turns with speedbar. If these wings are so unstable that you can't apply any amount of brake with any amount of speebar, then they are far too unstable to fy.
Matthew
I never said standing upright increases speed. I said the leaning forward into your shoulders straps increases speed a little and allows you to find your speedbar. I just watched a paragliding video and saw lots of people doing this. I'm gonna strap on my GPS next time and do some experiments in calm stable air leaning forward.
As to speedbar and brake. Again I never said to apply both brakes with speedbar, I said apply a little left and right brake to steer with speedbar. If you are doing regular coordinated turns with speedbar, I bet you are adding a little brake with your weight shift turn. This is inherent as your arm follows your body when you lean into the turn, applying a little brake. Unless you are deliberately go hands off, I bet you are applying a little brake in turns with speedbar. If these wings are so unstable that you can't apply any amount of brake with any amount of speebar, then they are far too unstable to fy.
Matthew
Thanks for this discussion. Very educational. I think I need to go to Europe and get lots of airtime!
I promise this is related somehow: a sailplane and towplane pilot I met this weekend is planning a trip to Spain and wants to learn winch launching technique. What was that location on the Costa del Sol for hang-or paragliding? Would there be saiplane operation near there because of good thermals, etc? I'll cross-post this to the HG side in case Danny will read it... - Hugh
I promise this is related somehow: a sailplane and towplane pilot I met this weekend is planning a trip to Spain and wants to learn winch launching technique. What was that location on the Costa del Sol for hang-or paragliding? Would there be saiplane operation near there because of good thermals, etc? I'll cross-post this to the HG side in case Danny will read it... - Hugh