注册 登录  
 加关注
   显示下一条  |  关闭
温馨提示!由于新浪微博认证机制调整,您的新浪微博帐号绑定已过期,请重新绑定!立即重新绑定新浪微博》  |  关闭

可小乐的天空

  大可小乐~~

 
 
 

日志

 
 
 
 

被动大折翼  

2007-08-27 16:15:09|  分类: 滑翔学院 |  标签: |举报 |字号 订阅

  下载LOFTER 我的照片书  |

译者按:原文标题为"真正的大塌陷",为理解方便本人译为"被动大折翼",意为非主动进入的大折翼,文中许多地方"塌陷"与"折翼"同意。译文后附有原文,文中若有理解不准之处请指出。

译文:

    我非常不愿意听到关于我的朋友伞失控后接地或抛付伞的消息,就在今年我的几位朋友已经碰到了这样的事情,他们都是在墨西哥的强气流中遭遇了大折翼。

    在欧洲的杂志和其他媒体上经常可以看到一些飞行员们关于大折翼的经验或忠告,但是在美国的刊物上却不太常见。两年前我在墨西哥遭遇了一次大折翼之后,开始咨询一些大牌飞行员关于大折翼的发生原因和预防方法,Joe Gluzinski、 Dave Bridges、 Chris Santacroce和 Robbie Whittal都和我交流了他们的观点,我相信还有更多的飞行员都了解大折翼,我也知道我并不是最有发言权的,但是我花费了时间去了解它,并与大家共同交流。

    这篇文章并不能面面俱到。请记住,不要仅仅是为了看看会发生什么就主动做大折翼。Steve Roti指出,主动折翼完全不同于被动折翼,因为飞行员已经做好了心理和行动准备,而且我们也无法模拟那些导致伞翼塌陷且难以恢复的乱流。在强气流中飞行过足够长的时间之后,遭遇大折翼只是迟早的事情。

    我在这里介绍的东西并不能代替一个飞行员在SIV或高级飞行培训学校里从资深教练那里获得的指导和实践经验,我尽可能搜寻每个机会去参加那些培训班,特别是我买了新伞之后。说实话,我不喜欢做技术动作时的那种紧张感,但是有一点对我来说却很值得(去做那些动作):当飞行中出现反常时,它会帮助你建立条件反射去应对,这一点是非常关键的。教练员的建议和忠告是非常有价值的,甚至关键时刻能会救你的命。所以尽自己一切可能参加一些培训班。

    本篇文章的意图在于让你对大折翼问题进行思考,促使你寻求避免大折翼的理论和技巧,并帮助你遭遇大折翼时顺利的从中恢复,避免使情况更加糟糕。

〖条件〗

    大折翼最有可能在强气流条件下遇到。如果你不是经常在强气流条件下飞行,象周末或度假的休闲飞行一般不会遭遇被动大折翼。大多数飞行场地有时都会有一些具有挑战性的气候条件,但在严重干旱的沙漠和某些山区却会经常性地出现乱流,比如Owens、 Chelan、 Elsinore、King Mountain、Valle de Bravo's El Penon、 Igualla等地区。如果你不是经常在这些地区飞行,那就得承认你并不是天生就有在这些地区安全飞行的本事。花些额外的时间在温和的气候条件下飞行以提高你的"抗打击能力"和飞行技巧。虚心一点可能会使你的生命有所保障。

〖预防〗

    99%的折翼都可以预防(当然,如果在Owens可能会只有92%),让我们来讨论一下预防。

    伞翼负载:对于你的伞翼来说,你自身的体重是重还是轻?是接近下限还是上限?一般而言,一个轻负载的伞翼事实上比重负载伞翼更加容易塌陷。因而要考虑使用一具超过中限负载的伞翼。配备水袋是一种补救措施,但也会造成一定的问题,比如着陆时更加费力,而且不方便。轻负载伞翼有时在失速和螺旋(spin)过程中表现得更加缓慢或温和,但是遭遇塌陷后恢复的也更慢。所以首先考虑的是,最好使用重负载伞翼来尽量避免失速、螺旋(spin)和折翼的发生。

    注意:最糟糕的是在没有心理准备的情况下进入了折翼。解决方法很简单!只要始终保持预想(塌陷)状态即可。那任何时候都能经受住折翼的考验。事先考虑到了预防方法和发生的可能性,你就能更近一步地预防或处理折翼。当这种理念成为本能,你会更加享受飞行的乐趣,在此之前,请不要沾沾自喜于自己的控伞能力,也不要对发生的意外感到过分惊奇。

    如果你正在使用加速杆或可调组带加速飞行,要清楚你的伞翼正处于一个新的攻角下,通常会增加进入折翼或前扣的危险。应保持预想(危险)状态并采用积极控伞飞行,这就是另一个预防技巧。

    积极控伞(主动飞行):利用你对刹车棒的力度感觉,来预感和预防折翼的发生。Robbie Whittall告诉我,假定我的每只手有5kg的重量:当感到拉力变轻时,往下拉一点维持住5kg的重力。感到变重时,往上送一点恢复到5kg的重力,你对拉力改变的反应越快,就会越主动地控伞。这种方法可以预防某些折翼的发生。
(译者注:这点请辨证接受,因为伞在前扣或后仰的时候,如果还保持5kg的重力,反而不能很好处理前扣或加重后仰,大折翼同样!)

    一些飞行员相信,每个人都可以仅仅通过刹车棒来持续地感觉伞翼的状态,达到主动飞行的境界。另外一些飞行员(比如我)还要依靠视觉检查---频繁地观察伞翼当前的状态。无论你是否观察伞翼,都不能保证一切,而仅仅是你进行实践并探寻主动飞行知识的一个起点而已。

    重心移动:一些飞行员过于地放松而忘记了重心移动是主动飞行非常重要的一个方面。别让气流把你象个土豆袋子似地甩来甩去。当座袋左右摇晃、摆动时,也要相应地左右移动你的屁屁,以保持你上身的稳定,并将重心均匀分布到两个主钩上面。稍后我会谈到遭遇大折翼时如何处理重心。但只要没发生折翼情况,当你在空中沉浮时就应该移动臀部来保持两边对称的拉力。

    大多数我交往过的热气流飞行员都喜欢将坐袋的带子调得更松垮一些,甚至不喜欢交叉带,这样他们能够更加真切地感觉到伞的状态,并且有更大的空间移动自己的重心。(对某些伞翼而言,具备一定的坐袋宽度和交叉带是为了安全认证和安全需要,所以在更换坐袋之前要搞清楚自己的伞翼的指标),刚开始一下子要放弃对紧绑式坐袋的安全依赖感是比较困难的,每次飞行都将坐袋逐渐地放松一点,这样可能会好一些。我从来没有听说过哪个飞行员会从一个坐袋(带子都系好)甚至是松垮坐袋里面掉出来。但前提是将带子扣都系好。可以考虑选择一个更加松懈的坐袋,看看你是否能适应它。

    水平飞行:折翼常常发生在靠近热气流的附近区域,但你想一直呆在热气流里面不出来也是不可能的。很多大折翼也发生在水平或直线飞行中。当你在热气流内部盘升(转弯)时,内侧一半伞翼承受高强度拉力,不太可能产生折翼。外侧一半伞翼有可能会塌陷,但不可能产生大折翼,而且通常是可以干预的。所以,为了避免大折翼,更好的办法是尽可能地在热气流里盘升。就像我的朋友Mark Heckler所说的那样,"主动转弯或被动转弯"(Turn or be turned)。将重心尽力移动到内侧,以保持内侧伞翼高强度的受力,另外还要主动控制外侧伞翼。当你必须要直线或水平飞行时,要意识到塌陷的可能性也在增加。

    还有其他飞行员的更多关于预防折翼的方法,比如研究实例地形。我希望有人会将这些经验和方法写出来,因为我想知道得更多。

〖处理大折翼〗

    好的,现在即使假定你已经掌握了预防大折翼的经验和方法,但还是有0.1%的可能性受到恐怖的大折翼的伤害。一些飞行员就是在这种情况下采取了错误的方式,使得情况变得更加糟糕。让我们看看如何处理它。

    首先,大折翼和非大折翼的区别是什么呢?这完全取决于伞翼和它的负载。每具伞都会有自己的表现。如果你想在强热气流条件下飞行,就要搞明白自己的伞翼在不同程度塌陷状况(大或小)下的不同表现。(不要仅仅是为了看看会发生什么就主动做大折翼!在教练的指导下安全地训练飞行技巧)每一具伞都有自己的阈值:小面积的折翼可以处理(manageable),大面积折翼则无法处理。Manageable是什么意思?且听下面分解。

    大多数飞行员都知道这样一句折翼受害者们总结出来的"咒语":"驾驶好你的伞,一切会好起来的"(Steer, then Clear),意在帮助你对自己的行动排出优先次序:不要把注意力全集中到使塌陷的翼端重新充气,而是首先设法重新控制好充气良好的未塌陷端,并且避免与其他飞行员碰撞。通常情况下这是个很不错的忠告和建议---但是它又没有自己的严格界限!这恰好就是一些飞行员遇到麻烦的情况。

    当你能驾驶你的伞翼(意为控制伞的运动方向)时,在塌陷端重新充气之前通过刹车棒和重心移动,折翼是可处理的(manageable)。但有时这是不可能的。当遭遇一个大折翼之后,只有一小部分伞翼能够充气。这一小部分伞翼几乎肯定会向前"俯冲"到的整个负载新的重心之下。伞很可能会进入螺旋。对于任何的塌陷状况,你都应该尽力移动重心到未塌陷一侧,这应当是自发的、条件反射式的动作。同时,当你利用刹车棒重新获得伞翼的驾驶能力之后,必须意识到:这一小部分未塌陷端的失速点变高(变早)了。很容易就会引起失速,并且最终导致反螺旋(negative spin)。

    一些飞行员表示,在进入失速和反螺旋之前通过刹车棒就可以感觉到:刹车棒的拉力可能会突然由重变轻,猛地进入水平螺旋。我知道用我的伞不能感受到这一点。仰头注意观察伞的状态可能会有所帮助。我认为在此种情况下(伞翼大面积塌陷,只有小部分伞翼充气,失速点明显提高,进入失速或反螺旋的趋势强烈)一个比较好的建议是:干脆就不要驾驶(steering)伞翼,因为你不能保证没有进入失速或反螺旋的危险。如果你确信自己具备安全驾伞的能力,那就去控制它,如果你没有这个能力,那就不要管它!(If you can, you should. If you can't, you shouldn't),其它你还能做什么呢?

    "让伞飞到它想飞的地方",每一种伞都各自不同,但是大多数非竞速伞都被设计成即使遭遇最大面积的塌陷之后也会重新充气。当重新充气之后,你还会重新获得驾伞的机会。我从Robbie Whittall那里得到的一个更好的建议是:如果你不能完全确认伞的状态,那就松开你的手,观察伞翼,直到你能够肯定的确认伞的状态,然后试着做出校正动作。(也有可能你对自己的伞更加了解,但我确信对自己的伞无法做到了如指掌)

彻底地从一次大折翼中恢复出来需要相当的高度,记得前文中提到过的"注意"和"水平飞行"这两点吗?塌陷发生之前要随时注意自己的对地高度,横向距离也非常关键:塌陷经常会把你水平甩出去。经历过大折翼的飞行员一般都很注意避免被"刮擦"(热气流或涡流中离山体特别近),如有必要准备扔出备伞。两年前,我在未扔备伞的情况下侥幸逃生,虽感幸运,但仍然对自己当时没有抛出备伞耿耿于怀。你怎么知道何时才需要扔出备伞?我想任何人都难以回答这个问题。你根本无法预见或想象到你可能会遭遇的那些稀奇古怪、匪夷所思的麻烦。

    一些比较"猛"的飞行员会跟抛出副伞的人开玩笑说,你们应该努力改出!在没有犯错的时候扔出副伞反而会使自己置身于重大的危险之中。空中遇到问题的时候,应当同教练或其他你信任的人保持联系,根据他们的指导安排你要做的事情。时刻注意自己的对地高度保持在300或你认为有意义的高度,否则你真的没有时间去分析、考虑或作出决断。我希望这些建议能引发一些讨论,最终会帮助我们避免严重的问题。或许我们都可以长期飞行,不再遭遇任何一次大折翼!

附原文:
Really Big Collapses

Paul Klemond, pkushga@kurious.org

I hate it when I hear stories of my friends losing control of their wings and either crashing or coming down under reserve parachute. This happened to several of my friends already this year, after they were hit with large collapses flying in strong thermal conditions in Mexico.

Lots of pilot wisdom is shared in the European magazines and elsewhere, but there's not much shared understanding of big collapses in print here in the US. After I took a big collapse and crashed in Mexico two years ago, I started asking some great pilots for help in understanding what happened and how I could have prevented it. Joe Gluzinski, Dave Bridges, Chris Santacroce, Robbie Whittall and others shared their valuable insight with me. I think more pilots should know about big collapses. I'm not the most qualified to write this, but I have the time so here it is.

This article is not the complete story. Please, do not go out and induce big collapses just to see what happens. Steve Roti points out that intentional pilot-induced collapses aren't the same as the real thing because the pilot is ready for them, and there's no way to simulate the nasty air that causes real collapses and that can make recovery problematic. Fly in strong thermal conditions enough and sooner or later you'll mother nature will demonstrate big collapse conditions for you.

What I'll present here is no substitute for the kind of instruction and practice one gets at an SIV or advanced maneuvers clinic, taught by a qualified instructor. I seize every opportunity I can to attend these clinics, especially after I buy a new wing. I really don't enjoy the adrenaline of doing a radical maneuver, but it's worth it to me: it builds the reflex piloting responses that are totally critical when something very unusual happens while you're flying. The instructor advice is priceless and may save your life. So go attend these clinics if you at all can.

This article is meant to get you thinking about big collapses, to spur you to seek out the understanding and skills you need to fly safely and avoid big collapses, failing that, to recover from them without making them worse.

Conditions

Big collapses are most likely to happen in strong thermal conditions. If you don't normally fly in such conditions, then don't expect to dive into it when you're on vacation. Most sites have some challenging conditions from time to time, but the gnarliest air is usually found in serious desert and mountain sites like the Owens, Chelan, Elsinore, King Mountain, Valle de Bravo's El Penon, Igualla, etc. If you don't often fly in such places, recognize that you're not born with the skills to fly safely there. Take some extra time in moderate conditions to develop your "bump tolerance" and skills. A little humility may save your life. Make your own decisions.

Prevention

99% of collapses can and should be prevented. (Maybe only 92% if you fly in the Owens a lot.) Let's discuss prevention.

WING LOADING: Are you light on your wing or heavy? Are you near the bottom of your wing's certified weight range, or near the top? It's generally true that lighter-loaded wings are more prone to collapses than heavier-loaded wings. Consider flying a wing on which you are more than half-way into the weight range. Carrying water ballast is an option but it poses certain problems, such as increased energy that needs to be dissipated at landing, and inconvenience. Lighter-loaded wings sometimes behave slower or more gently during stalls and spins, but they often reopen more slowly after a collapse. It's better to avoid the stalls, spins and collapses in the first place by flying a heavier-loaded wing.

AWARENESS: It's worst to suffer a collapses when you're not mentally prepared. This is easy! Just be paranoid ALL THE TIME. At any moment you could suffer a collapse. Think about prevention and contingencies, and you're already one step closer to preventing or handling a collapse. As this new mindset become instinct, you'll enjoy flying again. Until then, don't be complacent and caught by surprise.

If you're using your speed bar or your trimmers are out and fast, be aware that you're new angle of attack generally _increases_ your risk of collapse or front tuck. Be paranoid and use active piloting, the next preventative technique.


ACTIVE PILOTING: Use your brakes to feel, anticipate and prevent a collapse from happening. Robbie Whittall told me to pretend my hands are each 5-kg weights: when the pressure gets light, pull down to maintain 5-kg of pressure. When it gets heavy, let up to restore 5-kg of pressure. The faster you react to changes in pressure this way, the more actively you are piloting. This should prevent a lot of collapses.

Some pilots believe that everyone should be able to actively pilot by constantly feeling the wing through brakes alone. Other pilots (like me) rely additionally on a visual check, looking up at the wing frequently to see what it's doing. Whether you look up or not, this isn't the whole story - it's a starting point for you to practice and seek out knowledge of active piloting.

WEIGHT-SHIFTING: Some pilots relax too much and forget that weight-shifting is a very important part of active piloting. Don't just let the air throw you around like a sack of potatoes. As your harness rolls left and right, roll your hips left and right to keep your upper body stable and your weight distributed under both carabiners. Later I'll talk about what to do with your weight if you do take a collapse. But short of that happening, roll your hips to keep both sides pressurized as you take the ups and downs.

Most thermalling pilots I talk to prefer looser harness straps and loose or no cross-bracing - they're better able to feel what the wing is doing, and they have more room to shift their weight. (Some wings require certain harness width and cross-bracing as a certification or safety requirement - learn about your particular wing before changing your harness settings.) It might be hard at first to give up the secure feeling of a tight harness. Maybe loosen it gradually, flight by flight. I've never heard of any pilot falling out of a closed harness, even a loose one. Don't go overboard. But do consider a looser harness setting and see if you don't prefer it.

LEVEL FLYING: Collapses often happen near thermals, but that doesn't mean you're always working the thermal when you find it. A lot of big collapses occur during straight and level flight. When you're working a thermal (turning in it), the half of the wing on the inside of the turn is highly pressurized and very unlikely to collapse. The half on the outside of the turn may collapse but it is unlikely to be a large collapse, and is usually manageable. So, to avoid big collapses, it's preferrable to work thermals whenever possible. "Turn or be turned," as my friend Mark Heckler says. Weight shift hard into your turns, to keep that inside half highly pressurized. Actively pilot the outside half. And when you must fly straigh and level, be aware of the increased likelihood of collapses.

There's a lot more that someone could write about prevention, such as reading terrain for example. I hope someone writes about it because I'd like to know more too!

Handling Big Collapses

OK let's say you've mastered the prevention practices but you still get hit with that 0.1% case, the monster collapse. Here's where some pilots make mistakes that actually make matters worse. Let's look at what to avoid, and what to consider.

First, what's the difference between a big collapse and a not-so-big collapse? That depends entirely on the wing and the load beneath it. Your wing will have its own behavior. If you want to fly strong thermic conditions, you need to learn how your wing behaves after different degrees of collapses, big and small. (DO NOT go out and induce _big_ collapses just to see what happens! Work with your instructor to build your skills safely.) Every wing has a threshold: small collapses which are manageable, and big collapses which are not. What does "manageable" mean? Keep reading.

Most pilots know the collapse-victim's mantra: "Steer, then Clear." This is meant to help you prioritize your actions: don't focus on reinflating the collapsed side until you've regained steering control of the inflated flying side, and avoided a collision. This is generally good advice -- but it does have its limits! This is precisely where some pilots run into trouble.

A collapse is manageable when you are able to steer your wing, via brakes and weightshift, before the collapsed side reinflates. Sometimes this is not possible. After a big collapse, only a small portion of your wing will still be inflated. This small portion will almost certainly "dive" forward under the new load of your entire weight. Maybe the wing will enter a spiral. As with all collapses, you should shift your weight hard to the good (inflated) side of your wing. This should be automatic, reflex. Simultaneously, as you apply brake to regain steering control, you must beware: this new tiny wing of yours has a HIGH (EARLY) stall point. It is very common and very easy to cause it to stall, which will manifest itself as a negative spin.

Some pilots say you can feel this through the brakes before it happens: the brake pressure may suddenly go from heavy to light, precipitating the spin. I know I cannot feel this on my wing. Watching the wing might help. Better advice I think is to simply admit that you're better off NOT steering the wing since you can't safely do so without risking the stall/negative spin. No one can make this decision for you. If you can safely steer, you should. If you can't, you shouldn't. What else can you do?

"Let the wing fly - it want's to fly." Every wing is different, but most non-competition wings are designed to reinflate after even the biggest collapses. When this happens, you will regain steering. More good advice I got from Robbie Whittall: if you don't recognize exactly what your wing is doing, raise your hands, watch the wing and wait until you do recognize exactly what your wing is doing before trying corrective input. (Maybe you know better for your wing. I sure don't for mine.)

Clearly recovering from big collapses can require a lot of altitude. Remember the two points about "awareness" and "level flying"?

Be aware of your altitude above the terrain at all times, before collapses happens. Lateral clearance is critical too: collapses will often fling you horizontally. Those who've taken big collapses tend to avoid "scratching" - flying in ultra close to the terrain - in thermic or turbulent conditions. Be prepared to throw your reserve if necessary. Two years ago, I survived without throwing my reserve, but I felt very lucky and very stupid not to have thrown it. How will you know when you need to throw yours? I don't think anyone can answer that for you. You can't predict or visualize all the different weird wing troubles you might have.

Some macho pilots make fun of people who throw their reserves, saying they should have just worked it out. Not me. Make no mistake, throwing your reserve commits you to a course frought with its own significant risks. Before you're in the air having a problem, you should talk to your instructor and others you trust, and set your own course of action. Be aware every moment you spend below 300' AGL or whatever height you think makes sense, below which you don't really have time to analyze, ponder or decide. I hope these ideas spur some discussion that will eventually help us all avoid serious problems. May we all fly for a long time and never have any big collapses!

  评论这张
 
阅读(39)| 评论(0)
推荐 转载

历史上的今天

评论

<#--最新日志,群博日志--> <#--推荐日志--> <#--引用记录--> <#--博主推荐--> <#--随机阅读--> <#--首页推荐--> <#--历史上的今天--> <#--被推荐日志--> <#--上一篇,下一篇--> <#-- 热度 --> <#-- 网易新闻广告 --> <#--右边模块结构--> <#--评论模块结构--> <#--引用模块结构--> <#--博主发起的投票-->
 
 
 
 
 
 
 
 
 
 
 
 
 
 

页脚

网易公司版权所有 ©1997-2018