descending out of thermals

[somethinelse 0]

My istructor was talking to me about how far to pull down the toggles for best effect.

...from all the way up, to about shoulders, is that considered about half brakes? and then lower to about chest-waist, is that considered 3/4? where does it start to be an actual flare?? I'm 5'5", under a 280 chute.

I was playing around a lot trying to find how the canopy reacted to lighter and heavier braking.

[somethinelse 0]

I'm not sure why I've been under 280's so long. I'm progressing thru my program, but gotta a lot to cover yet. It's a really docile chute size, but such a big chute does present other problems for me.

My instructor is a really high#jumper& extremely experienced and I trust him& his judgement completely. He says I'm ready, now, so he's gonna start down sizing me now.

[somethinelse 0]

Jerm,

Don't worry dude. I'm No kid. I know advice for what it is...Especially from thus far faceless strangers, Ya Dig?

but I DO GLEAN valuable advice from the forums, and take it to my dz trainers for their take on what best for me, anyways.

Love the different take and expereince that gives me differing scenarios and applications that all these folks have had.

So thanx for your concern.
You seem truly thoughtful.

[jerm 0]

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It is aparent that enough people dislike the advise I gave so I am going to give up on the thread. If I could I would delete my original post. I personally believe teaching S turns on final is about as dangerous as you can get at a busy DZ. It will someday cause a canopy collision.

if you beliece that properly executed turns at a safe height made by someone looking before the turn are more dangerous than having students flying at the stall point of their canopies in likely turbulent conditions only to have them surge at the ground right before landing, i hope you're never in a position of authority at a DZ.

that you're suggesting is tantamount to having students performing hookturns. You're removing the turn, but you're still ahving them diving at the ground with little room for error. Students can barely tell wha height to flare at on a normal approach, nevermind what you're describing.

As i said before I'm not debating (or supporting) the merit of your advice, my issue is more with your targetted audience.

here's a short version: At best it's an advanced (read: dangerous) technique, don't suggest it to students.

Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time

[jerm 0]

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Jerm,

Don't worry dude. I'm No kid. I know advice for what it is...Especially from thus far faceless strangers, Ya Dig?

I dig, but not everyone who reads this will be as savvy.
I think most people would discourage that if it were run by them, but my fear is someone going out, trying it w/o talking to an instructor and breaking themselves because no one said they shouldn't do it. Well, i'm saing it, for you and any other students who might be reading.

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So thanx for your concern.
You seem truly thoughtful.

quite welcome... and thank you.

Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time

[ManBird 0]

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This advice scares me a bit for a few reasons.
First, in low or no wind, all canopies that I know of will fly a flatter glide at a certain mid-range brake setting. (Could be 1/4 brakes, could be 1/2 brakes.)

Za? On my Sabre2 107 and my Katana 97, this is NOT the case. When I'm setting up for a 270 and it looks like I'll be long, I fly in brakes to shorten up the flight. The deeper the brakes, the steeper the glide (even though the hang time is longer). I'm generally flying crosswind or into the wind, though, and land downwind. Brakes + downwind can mean a flatter glide, if the tailwind is fast.

This, of course, is near landing. Descending from higher altitudes, I do what hookitt said... go somewhere else. On the HP side, most people at our DZ fly to sort of an unofficial "holding area" to burn altitude down to about 1,000' - 1,500' before flying back to the pond. Wide s-turns in the pattern (mainly 1,000' and under) are not a good idea.

As far as stalling... don't do it. You don't need to be THAT deep in brakes. C'mon. And releasing the brakes doesn't have to happen that close to the ground. Do it a few hundred feet up.

Edit: Looks like a lot of overthinking is going on here. You can shorten up your flight path with 1/2 brakes (which won't stall a canopy, ESPECIALLY a student canopy) or by losing altitude with maneuvres *out of the pattern*. Your canopy should be flying as you get close the ground. When you get there, pull the thingies, smoothly and symmetrically. Done. What's this stall and "cold edge" stuff?

Do what you gotta do, and don't nail anyone else while doing it.

"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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[Fast 0]

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This advice scares me a bit for a few reasons.
First, in low or no wind, all canopies that I know of will fly a flatter glide at a certain mid-range brake setting. (Could be 1/4 brakes, could be 1/2 brakes.)

Za? On my Sabre2 107 and my Katana 97, this is NOT the case. When I'm setting up for a 270 and it looks like I'll be long, I fly in brakes to shorten up the flight. The deeper the brakes, the steeper the glide (even though the hang time is longer). I'm generally flying crosswind or into the wind, though, and land downwind. Brakes + downwind can mean a flatter glide, if the tailwind is fast.

I don't really get this. It would seem to me that the glide ratio of the canopy with certain control inputs would have nothing at all to do with what the wind is doing. Your flying in a moving mass of air.

If you want to talk glide relative to the ground, I think that is a bit differnt than what glide technically is. It would seem to me that the true glide ratio of the canopy is either more or less with brakes applied not both. If you want to compare it to what is happening on the ground it seems that it is highly dependent on your position and direction (relativly) in a moving mass of air.

I still maintain that my canopy flies farther with some level of brakes applied in no wind conditions. Maybe my perception is just wrong, I dont know. I will make a point to research this more for personal knowledge.

~D
Where troubles melt like lemon drops Away above the chimney tops That's where you'll find me.
Swooping is taking one last poke at the bear before escaping it's cave - davelepka

[xsynergist 0]

Assume still air. Assume two wings with the same glide slope one a small performance wing and one a larger wing. They both descend along the same glide path only the smaller wing descends much more quickly. A gliding wing works in gravity by converting Drag into Lift. The forces acting on the wing are balanced at a certain point described as the Lift to Drag ratio or L/D. In still air with no user input this is the same as the wings glide ratio. The angle of attack of the wing increases with brake input which exchanges forward speed into lift. This will increase your glide ratio and slow you down up until the stall point of the wing.(The wing is more susceptible to turbulence and collapsing the closer you get to the stall point) This is true on the small wing as well as the large. Where things get tricky however when is when you factor in the wind. The smaller wing which travels much faster down the glide slope has less time to be affected by the wind (movement of the air body) than the larger wing and will show less deviation in glide relative to ground than the larger wing. So while landing in a particular place on the ground will be dependent on your wings size and performance evenly applying any brakes up to a point short of stall will will keep you in the air longer on any wing. I believe this to be correct but I am not an aerodynamics professional.

On a paraglider when we have too much lift and wish to descend faster we decrease the wing size by pulling on the outside lines or deform the wing by pulling on the b risers to induce a "B"line stall. I do not know if these techniques can safely be used on a skydiving canopy.

Does anyone know?

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Why get married? Just find a woman you hate and buy her a house.

[relyon 0]

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On a paraglider when we have too much lift and wish to descend faster we decrease the wing size by pulling on the outside lines or deform the wing by pulling on the b risers to induce a "B"line stall. I do not know if these techniques can safely be used on a skydiving canopy.

Does anyone know?

I use outside A-line and/or B-line control on my Lightning (non-cascaded outside lines) quite frequently. I've also done this on an Express (also non-cascaded) and a Triathlon (cascaded) with similar results, so the answer is yes in at least some cases.

Pulling (4"-8") the A-line has a tendency to collapse the cell when the topskin gets pulled below the stagnation point, so I use that less. Pulling the B-line has a similar effect without the cell collapse, so I use that most of the time. In either case both the glide angle and descent rate increase dramatically.

Bob

[ManBird 0]

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I don't really get this. It would seem to me that the glide ratio of the canopy with certain control inputs would have nothing at all to do with what the wind is doing. Your flying in a moving mass of air.

So maybe we should all jump rounds again. Of course our control inputs changes our glide ratio. Ahd how you fly in various windspeeds makes a huge difference! You should know this. If you have a strong headwind, do you think flying in brakes will increase your glide? No, you use rear risers flatten out your canopy relative to the air infront of you.

Think about it... when your canopy is in full flight, there is not so much drag, allowing to move forwards quickly. When you deflecting the tail, you're increasing the surface area exposed to the air in front of you -- less forward speed. This decreases your descent rate, as well, since you are cupping air, but for the most part.

In the case of a strong tailwind, the decrease in descent rate due to flying in brakes may actually increase your glide ratio. Using arbitrary figure, lets say that yoru canopy descends at 16fps and moves forwards at 32fps, in full flight. That's a glide ratio of 2:1. When you hit the brakes, you descend, let's say, 11fps, but your forwards speed slows down to 16fps. That's a glide ratio of about 1.45:1. If you have a 15mph tailwind, your groundspeed is now 38fps, for a glide ratio of 3.45:1. But if you were in full flight, you'd be going 54fps forwards, and 16fps down for a 3.37 glide. The difference is marginal, but you will actually cover more ground in brakes.

Now if you face into the 15mph wind, using these figures, full flight will yield a 0.62 glide, where as brakes will have you flying straight down, if not backwards, regardless of descent rate.

"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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[pilotdave 0]

Your glide ratio (through the air) increases when you add brakes, not decreases like you suggest. An accuracy canopy can sink in deep brakes... it has a lower glide ratio in deep brakes. But a modern sport canopy can't do that. Adding brakes increases your glide ratio in a no wind situation. So of course your glide ratio over the ground is even better with a tailwind and brakes.

When you pull the brakes, you are right that your airspeed decreases and so does your descent rate. But the descent rate decreases more quickly than the airspeed. That allows you to glide farther with brakes than without.

Into a strong wind is a different story. The lower groundspeed will cause a steeper descent (in relation to the ground) when you apply brakes. That's the only way you can sink a modern sport canopy using brakes.

Seriously, take Scott Miller's canopy course. He does a great job of explaining this stuff and gives you a chance to see it for yourself.

Dave

[ManBird 0]

I use brakes to shorten up my flight path to my setup point for a 270 on my Katana 97, and did the same thing on my Sabre2. That's flying into a crosswind. And I also fly in brakes to sink my Fox 245. Same results. I've done this more times than you have total skydives. I've taken several canopy courses and have never heard of braked flight increasing your glide in a headwind or crosswind. I also apply the same prinicple to wingsuits.

I now feel TALONSKY's frustration. I'm out.

"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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[xsynergist 0]

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I've taken several canopy courses and have never heard of braked flight increasing your glide in a headwind or crosswind. I also apply the same prinicple to wingsuits.

Brake application only increases your glide ratio inside the moving airmass and not relative to the ground. The increased drag due to an increased angle of attack decreases your penetration into the wind. Just because the glide ratio is higher doesn't mean that it is more efficient. The increase in drag in overcoming the headwinds or crosswinds force can more than offsets the gain in glide ratio and the net effect is your apparent glide is decreased. I think this is essentially correct.

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Why get married? Just find a woman you hate and buy her a house.

[ManBird 0]

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The increased drag due to an increased angle of attack decreases your penetration into the wind. Just because the glide ratio is higher doesn't mean that it is more efficient.

Major contradiction here. Decreased penetration means a lower glide ratio. How are you defining glide? It's generally horizontal:vertical, but it sounds like you're saying vertical:horizontal.

"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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[xsynergist 0]

Penetration into the wind is relative to a fixed point on the ground. From the wings perspective it is merely gliding through the airmass at a constant speed determined by its design and wingloading. If the Airmass you are in is still or moving in the same direction you are going then your apparent glide (apparent relative to the ground) increases. If the airmass is moving perpendicular to or away from the point on the ground you are using for reference then application of the brakes can create an apparent decrease in glide while in all actuality the increase in the angle of attack does increase your actual glide ratio through the airmass. The reason that it seems as if your glide is decreasing is because the added drag has slowed you relative to the airmass. The airmass is still moving at the same velocity so your apparent glide decreases. The same thing works in obverse. If you decrease the angle of attack by pulling down on your "A"s your actual glide ratio will decrease but your speed through the airmass will increase and you will penetrate into the wind (relative to the ground) better and increase your apparent glide.

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Why get married? Just find a woman you hate and buy her a house.

[ManBird 0]

After 10 hops and pops from 3,500' - 14,000' this weekend, all I have to say is this: throw your theories out the window and actually fly a parachute.

"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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[mattjw916 2]

ding ding ding... we have a winner!!!

NSCR-2376, SCR-15080

[xsynergist 0]

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ding ding ding... we have a winner!!!

I don't know about that.

But you can't knock manbirds advice!

The only confusion I see here is that apparent Glide which is relative to the ground and Glide Ratio which is relative to the airmass are being used interchangeably. I don't see a conflict in the actual methodolgy. Just do what you know works.

P.S. GravityGirl Rocks!