kelel01 1 #1 December 11, 2003 I am a bit confused-- I was just reading in the incident forum about flying in half brakes making you go FARTHER, but I have always been told that it will make you land CLOSER. Can anyone shed some light on this subject for me? Thanks! Kelly Quote Share this post Link to post Share on other sites
kelel01 1 #2 December 11, 2003 Ok, look who just got on board. (That would be me). Somebody please correct me if I'm wrong, but my powers of deductive reasoning seem to have kicked in, and I'm thinking that going INTO the wind, it will make you land closer, or shorter. Going WITH the wind (downwind), it will make you land farther out. Correct? Kelly 1 Quote Share this post Link to post Share on other sites
billvon 3,006 #3 December 11, 2003 >I'm thinking that going INTO the wind, it will make you land closer, > or shorter. Going WITH the wind (downwind), it will make you land > farther out. Correct? Usually, yes. 1 Quote Share this post Link to post Share on other sites
SkydiveNFlorida 0 #5 December 11, 2003 I also posted a link in that thread to an article that would be worth reading. :) Angela. Quote Share this post Link to post Share on other sites
Dagny 0 #6 December 11, 2003 Oh, if I could only remember what Scott said about flying in brakes....why didn't I write this down? If I recall, it was said that flying in brakes (from 1/4 to 3/4) into the wind will flatten the glide and cause the canopy to travel further than leaving it in full glide. And, in a no wind situation, flying in brakes will cause the canopy to land short of the intended target? Or have I remembered this backward? Insight, please, billvon!Take me, I am the drug; take me, I am hallucinogenic. -Salvador Dali Quote Share this post Link to post Share on other sites
FrogNog 1 #7 December 12, 2003 QuoteUsually? Half brakes makes your canopy fly slower. If this effect is achieved without altering the angle of your canopy glide (i.e. your forward speed and your downward speed are attenuated proportionately), and the winds are not high enough to make you move backward at half brakes, then you are precisely correct that half brakes flying against the wind will make you land closer to where you are now than full flight would, and half brakes flying with the wind will make you land further from where you are now than full flight would. When the winds are above a certain speed, however, this is no longer true because the definition of "closer" is ambiguous with respect to direction toward or away from the target. (If "closer" is redefined in terms of "positive distance in the direction you are facing", then again you are precisely correct, even in winds great enough to move you backwards.) The quick example is if you are at full flight into the wind and going to touch ground straight down, then if you go to half brakes you will land backwards somewhere which would usually not be classified as "closer". Ignoring higher winds that blow you backwards at full flight or in brakes, the other catch is that on all canopies, after a certain level of brakes, the glide ratio worsens; that is, the reduction in downward speed of the canopy proportionately outpaces the reduction in forward speed of the canopy. This happens because ram-air canopies are wings and a significant part of their slow decent rate is caused by generating lift as they fly through the air. Reducing their speed through the air reduces this lift, and it also reduces the ram-air pressurization necessary to maintain the wing shape, typically decreasing its lift-generating efficiency per units of speed. The reason we say you are "usually" right is that there's a gray area between how far into brakes you are, what canopy type/size/loading you have, and how much wind we're talking about. In light winds it's also hard to tell what will happen. With some canopies, the ones trimmed "pointed steeper down" than others, slight brakes is rumored to actually improve their glide a little bit. Rear risers is supposed to do this more. If the increase in glide ratio from trimming flatter (via slight toggle input or some rear riser input) outpaces the reduction in canopy flight forward speed component, your extra time in the air will afford you more forward movement through the air. If there is no wind, you will land even further in the direction you are facing. I believe if the wind is less than than the average of your full-flight forward canopy speed component and your new forward canopy speed component, you will land further in the direction you are facing, if the wind is more than the average of your two forward canopy speed components (full-flight and new) you will land less far in the direction you are facing, and if it is equal you will land in the same place but be in the air longer to enjoy the view and work out your arms. The simplification of all this calculation is this: your canopy movement across the ground is determined by your canopy's forward movement component plus or minus the wind speed (plus if you are flying with the wind, minus if you are flying against the wind) multiplied by the time you are in the air. You have the ability to flip the sign of the wind component (by doing a 180 to face the other way) and you have the ability to adjust your forward speed component and time aloft using the toggles - but this control is limited and the two outputs are inversely, nonlinearly related. (Please accept my apologies for the simplifying assumption that all flight is done facing directly toward or away from the wind, or in zero wind. It gets only slightly more difficult to compute and understand but extremely more lengthy to describe flying at an angle to the wind.) -=-=-=-=- Pull. Quote Share this post Link to post Share on other sites
billvon 3,006 #8 December 12, 2003 >Usually? In very light winds, you may go farther in partial brakes (say, 1/4) even if you're downwind. Quote Share this post Link to post Share on other sites
ianmdrennan 2 #9 December 12, 2003 QuoteAnd, in a no wind situation, flying in brakes will cause the canopy to land short of the intended target? No, it'll take you FARTHER in no wind. Brakes into the wind CAN stop your movement over the ground (not to be confused with airspeed) if the winds are strong enough. Whether or not you'll go futher in brakes into the wind depends on the winds strength and your canopies forward speed and glide. Blue skies IanPerformance Designs Factory Team Quote Share this post Link to post Share on other sites
cvfd1399 0 #10 December 12, 2003 I had a question about 1/4-1/2 brakes on landing. When I did my first jump when I was approx 20 feet off the ground I slowly started to flare to 1/4-1/2 not nearly enough to stall it, and it felt really good. At approx 6 feet the radio said flare flare and I made a light one knee slide landing. When the guy on the radio came to me he told me if I ever do that again that I could hurt myself. It felt really good to me it was like stopping at a red light I slowed down a bit and flared to a stop. I realized that if I started to stall I would release the brakes. My question is do you or should you come in with a light brake? Sometimes? Never? What would be some contradictions for not doing it? This is all based on a no to light light wind situation. I realize also that adding winds brings in a whole bunch of other variables to add in to the mix. Quote Share this post Link to post Share on other sites
billvon 3,006 #11 December 12, 2003 >I realized that if I started to stall I would release the brakes. Do not do that! If you are near-stall at 20 feet and you release the brakes your canopy will nearly go into freefall as it tries to recover its airspeed. If you flare too high, hold the brakes until you impact and prepare to PLF. At most, if you flare way too high, ease up on them just enough to keep it out of a stall (say, go from full to 3/4 brakes, or 3/4 to 1/2 brakes) then flare again just before impact. The second flare will slow you down a little but not much. Again, prepare to PLF. >My question is do you or should you come in with a light brake? >Sometimes? Never? If you cannot tell where you are going to land (say, you're landing in water, or over snow, or in darkness) you may want to go to 1/2 brakes and hold them. That will slow you down without stalling, and your landing will not be as bad as a no-flare full flight landing. Accuracy canopies can be landed in deeper brakes, but a) they are designed to sink a jumper nearly straight down and b) the landing won't be as soft as it otherwise would be. In general, most canopies land best if you can trade all their forward speed for lift in the flare. To do that, you have to _have_ forward speed, which is why most people enter the flare with normal (or even higher than normal) airspeed. Quote Share this post Link to post Share on other sites
cvfd1399 0 #12 December 12, 2003 I understand and will follow how it should be done from now on. What I did was out of instinct. It seemed good though. It was a 370sq.ft canopy. It just slowed down and coasted in. After reading how a fast released brake could turn into a down plane at 20 feet it seems like not the right place to be in. Quote Share this post Link to post Share on other sites
FrogNog 1 #13 December 12, 2003 QuoteI understand and will follow how it should be done from now on. What I did was out of instinct. It seemed good though. It was a 370sq.ft canopy. It just slowed down and coasted in. After reading how a fast released brake could turn into a down plane at 20 feet it seems like not the right place to be in. Not a down-plane, exactly. That's two canopies working together to point straight down. Your issue is called I think "diving". With your previous post, the reason you don't want to flare partially higher up is because the flare is a way of landing at low downward speed by getting the canopy to make more lift than normal for a short period of time. This is done by tilting the canopy up a little bit which makes it make more lift but slows it down. If it runs out of speed, it will start to fall again and will deflate, too. The goal of flaring is to keep the canopy flying normally until juuuuust the right point very near the ground, and then use up the canopy's speed to make a soft landing, depleting the canopy's speed right as you step onto the ground. (Give or take. ) If you slow the canopy down before you get to the ground, it can't give as strong an arrest of your downward movement. Your two options with a slow canopy are: 1. allow it to regain a little or a lot of its speed (which means it will dive a little or a lot) or 2. keep it going about that slow and have less (or no) ability to flare. This second option can be not so bad, or inconvenient, or dicey, or somewhat painful, or very painful, or life-threatening, depending on how slow you got it, how your canopy reacts to being that slow, and what happens with changes in wind. I have landed a 290 sf student canopy at half brakes with no flare and I was OK, because it wasn't coming down that fast. In fact, that's what they told us to do on our first jump course IF we were going to have an off landing and before we learned how to judge our own flares. But it's not the ideal way, and I sure wouldn't want to do it for fun on smaller, faster canopies, so do what your instructors tell you. -=-=-=-=- Pull. Quote Share this post Link to post Share on other sites
cvfd1399 0 #14 December 12, 2003 Well since it was a easy landing noone really said anything to me other than the guy on the radio kept saying hands up hands up. After I landed he told me if I brake like that again I could hurt myself. Quote Share this post Link to post Share on other sites
riggerrob 643 #15 December 13, 2003 ... a 370sq.ft canopy ... will forgive a lot of sloppy techniques. If you prefer this approach technique, then buy a (big) canopy that is specificlly designed for this type of approach(i.e. Para-Foil or Eiff). Quote Share this post Link to post Share on other sites
