看着吓人，可惜这种手持类啪啪的威力不会超过14W，这已经是手持中威力最大的玩具之一。不过手持接触类的实用效果都比较差，远远不如Taser这种空气射针强大。
2006-12-30
2006-12-28
2006-12-24
刺激剂
刺激剂，小瓶的就是民间常说的防狼剂，据说国产辣椒剂都是很烂的辣椒+水配方，普遍没什么威力。我们可以认为真正有效的刺激剂是军用的化学制品，偶玩过正经的CR喷剂，体验过其威力，只是轻微暴露在CR喷尘柱边缘1米的地方，参与测试的两人瞬间扭头就跑就，眼中严重异物感，口鼻失调，幸好没吸到肺里……那间屋子很长时间不能进去，进去眼睛就不舒服。毕竟是正经的军警用品，威力那叫一个可怕。最妙的是喷剂粘在皮肤上后，不得用水洗，否则，嘿嘿嘿^^，威力加倍~~
新版的，被广泛民用的无毒的东东叫做辣椒素（OC），其实正经OC不是辣椒提炼的，依然是人工合成的。据说可以比前辈们更加有效地对付无痛感的精神病人和醉酒者。
刺激剂是对眼和上呼吸道有强烈刺激，人员接触后出现剧烈眼疼、流泪、咳嗽、胸痛而暂时失去战斗力。主要代表有苯氯乙酮（CN）、亚当氏剂（DM）、CS和CR。外军常用来骚扰对方军事行动，并用作“抗暴”剂，目前仍有装备。
按其对刺激作用部位不同分两大类：
1．催泪剂（lachrymator）：以眼刺激为主。极低浓度即能引起眼强烈疼痛、大量流泪、怕光和睑痉挛。高浓度对上呼吸道和皮肤也有刺激作用，主要代表有CN和CR。
2．喷嚏剂（sternutator）：以上呼吸道强烈刺激作用为主，引起剧烈和难以控制的喷嚏、咳嗽、流涕和流涎，并有恶心、呕吐和全身不适。对眼也有刺激作用，因能致吐，故又称呕吐剂，主要代表有DM。
CS对眼和上呼吸道均有强烈刺激，对皮肤也有明显的刺激作用，实际上，任何一种刺激剂的作用都是多方面的。
刺激剂均为高沸点的固体化合物，性稳定。主要理化性质见表。
施放方法和毒性
中毒表现与诊断
新版的，被广泛民用的无毒的东东叫做辣椒素（OC），其实正经OC不是辣椒提炼的，依然是人工合成的。据说可以比前辈们更加有效地对付无痛感的精神病人和醉酒者。
刺激剂是对眼和上呼吸道有强烈刺激，人员接触后出现剧烈眼疼、流泪、咳嗽、胸痛而暂时失去战斗力。主要代表有苯氯乙酮（CN）、亚当氏剂（DM）、CS和CR。外军常用来骚扰对方军事行动，并用作“抗暴”剂，目前仍有装备。
按其对刺激作用部位不同分两大类：
1．催泪剂（lachrymator）：以眼刺激为主。极低浓度即能引起眼强烈疼痛、大量流泪、怕光和睑痉挛。高浓度对上呼吸道和皮肤也有刺激作用，主要代表有CN和CR。
2．喷嚏剂（sternutator）：以上呼吸道强烈刺激作用为主，引起剧烈和难以控制的喷嚏、咳嗽、流涕和流涎，并有恶心、呕吐和全身不适。对眼也有刺激作用，因能致吐，故又称呕吐剂，主要代表有DM。
CS对眼和上呼吸道均有强烈刺激，对皮肤也有明显的刺激作用，实际上，任何一种刺激剂的作用都是多方面的。
刺激剂均为高沸点的固体化合物，性稳定。主要理化性质见表。
刺激剂的主要理化性质
| 项 目 | 西埃斯 | 西阿尔 | 苯氯乙酮 | 亚当氏剂 |
| 化学名 | 邻氯苯亚甲基丙二腈 | 二苯并(b,f)-1,4-氧杂吖庚因 | 苯氯乙酮 | 氯化二苯胺胂 |
| 美军代号 | CS | CR | CN | DM（苏军代号为（P-15） |
| 外 观 | 白色～淡黄色结晶 | 黄色粉末 | 无色或黄褐色～暗绿色结晶 | 金黄色～暗绿色结晶 |
| 气 味 | 胡椒味 | 无 味 | 荷花香味 | 无 味 |
| 溶点(℃) | 95～96 | 72 | 59 | 195 |
| 沸点(℃) | 310～315 |
| 244～245 | 410 |
| 溶解度 | 难溶于水，易溶于有机溶剂 | 难溶于水，易溶于乙醇、丙烯二醇和盐水中 | 稍溶于水，易溶于有机溶剂 | 难溶于水，稍溶于有机溶剂 |
| 水 解 | 在中性溶液中半减期为10min；碱性溶液中水解速度更快 | 不易水解。在浓盐酸或20％氢氧化钠水溶液中回馏数小时仍稳定 | 常温时不易水解，碱性溶液中长时间煮沸才能水解 | 极慢，加碱则加速水解，产物仍有毒，也具有喷嚏作用 |
| 氧 化 | 与高锰酸钾作用生成无刺激性氧化产物 |
| 与强氧化剂（如次氯酸钙）作用，生成无毒的苯甲酸 | 与强氧化剂（如次氯酸钙）作用，生成物无刺激作用 |
施放方法和毒性
刺激剂都有固体结晶或粉末。使用时可直接喷洒成粉末状，也可用热分散法造成有毒烟雾，弥漫散布于局部空间。刺激剂对人的毒性见表。
表四种刺激剂对人的毒性
| 名 称 | 阈刺激浓度* | 骚扰浓度**（mg/m3） | 平均失能剂量 | 半数致死剂量 |
| CN | 0.3 | 5 | 80 | 8500～11000 |
| DM | 0.1 | 2 | 22 | 15000～30000 |
| CS | 0.05 | 1 | 15 | 61000 |
| CR | 0.005 | － | 0.64 | － |
* 暴露1分钟引起刺激的起始染毒浓度 ** 使人不安宁的染毒浓度
中毒表现与诊断
刺激剂的主要毒理作用是直接刺激粘膜和皮肤，尤其前者为显。一般引起局部的非特异性炎症：睑痉挛、结膜充血、结膜炎、角膜炎或溃疡；接触上呼吸道可引起 鼻、咽喉炎或气管炎。严重者可发生粘膜上皮坏死、粘膜下水肿和炎细胞浸润；皮肤损伤则属接触性皮炎，严重者发生小水疱和溃疡。多汗和薄嫩的皮肤易受损伤， 产生相当于Ⅰ～Ⅱ度皮肤化学烧伤。
刺激剂共同的中毒特点是：低浓度即可产生眼和上呼吸道的强烈刺激，几无潜伏期；伤员的主观感觉严重，客观检查体征少而轻；脱离接触后症状很快减轻和消失（DM中毒后可有后继作用）；刺激阈值和致死浓度之间差距很大，一般较难造成严重损伤和死亡，预后良好。
（一）中毒表现
1．CS中毒表现：无防护情况下，人员接触CS毒烟后，立即双眼灼痛、大量流泪、眼睑痉挛、严重影响视力；剧烈咳嗽、鼻喉烧灼感；喷嚏、流水样鼻涕、呼 吸紊乱、胸闷、胸骨后疼痛；高浓度下可有恶心、呕吐；暴露部位皮肤和头面部、颈部及手腕部出现烧灼痛。严重者经数小时到十几小时后可出现红斑和小水疱。离 开染毒区后刺激症状迅速缓解，5～10分钟后大部症状基本消失，视力也可恢复。长期暴露在高浓度CS染毒空气中可发生支气管肺炎、肺水肿，个别严重者可因 呼吸衰竭死亡。环镜温度愈高，刺激症状愈重。
2．CR中毒表现：眼接触CR后立即有刺痛和烧灼痛，并产生眼睑痉挛、大量流泪等。浓度愈高，刺激症状愈重、愈持久，一般不会引起眼器质性损伤。CR对 皮肤的刺激强度比CN和CS大，可以产生红斑，一般不产生水疱。皮肤经洗消后红斑会迅速消失。CR对眼的刺激作用较CS约强10倍，对呼吸道的刺激作用较 CS轻，仅有鼻刺激感、流涕、鼻塞等症状。CR进入口腔可引起灼痛和不适，有喉头紧迫感，伴有大量粘稠的分泌液，持续时间一般不超过5分钟。
3．CN中毒表现：CN是典型的催泪剂。眼接触烟雾或蒸气，立即引起眼睑痉挛和大量流泪。如暴露时间很短，上述症状仅持续数分钟。暴露时间稍长可引起结 膜充血、水肿、羞明和流泪，持续2～5天。CN的液滴或颗粒进入眼内，则有腐蚀作用，发生浅层或深层角膜炎，需数天或数周才能痊愈。严重者留有疤痕，视力 减退甚至失明。在较高浓度CN的作用下，可出现上呼吸道刺激症状，如咽喉烧灼痛、咳嗽、声音嘶哑、流鼻涕等。有时有恶心，一般持续3～5天，在极高浓度或 较长时间中毒情况下可引起肺水肿或继发性肺部感染而死亡。CN可引起多汗潮湿的皮肤刺痛、红斑和水肿；严重者引起小水疱和溃疡。反复接触中致过敏性皮炎。 仅少数严重中毒病例才出现全身中毒反应，如头昏、头痛、眼球及眶部疼痛、肌肉松驰无力及心脏功能减弱等。
4．DM中毒表现：DM是典型的喷嚏剂，以刺激上呼吸道为主，引起直呼吸道辣椒样刺激作用。鼻腔、鼻窦、副鼻窦烧灼痛、疼痛及发胀，喉头有强烈灼痛、胸 闷、胸骨后疼痛、反射性喷嚏、咳嗽不止。重者有恶心、呕吐、剧烈头痛、上下颌骨、齿龈、内耳等部位疼痛。但以连续不停地喷嚏和剧烈的脑骨后疼痛为其特征， 故又名“胸痛剂”。DM对上呼吸道有“后继作用”，即中毒者离开染毒区后，10～20分钟内症状继续加剧。经20～120分钟后逐渐缓解消失。长时间吸入 高浓度DM可引起肺水肿及支气管炎。DM对眼的刺激作用较轻，可引起流泪、羞明及异物感。皮肤刺激作用较轻。高浓度下，暴露部位皮肤有瘙痒、灼痛和刺痛， 可产生红斑、水肿或水疱，1～2天内症状逐渐消失。误服染毒水或食物后，可引起消化道症状。大量DM吸收后具有砷中毒的全身症状，表现为精神抑郁、烦躁不 安、肌无力，运动失调、四肢麻木，数日后可恢复健康。几种刺激剂的中毒特点比较见表。
表四种刺激剂的中毒特点比较
| 项 目 | CS | CR | CN | DM |
| 眼刺激和催泪 | 强 | 极强 | 极强 | 弱 |
| 喷嚏咳嗽胸痛 | 强 | 很弱 | 强 | 极强 |
| 皮肤刺激 | 较强 | 强 | 强 | 弱 |
| 恶心呕吐 | 有 | 一般无 | 一般无 | 有 |
| 全身吸收中毒 | 轻 | 一般无 | 轻 | 较重 |
| 离开毒区后症状持续时间 | 短 | 最短 | 较长 | 长 |
（二）诊断
根据中毒史、典型中毒症状和毒剂侦检结果即可确诊。除了几种刺激剂之间要相互鉴别外，还要与光气、氢氰酸、氯化氰以及蒸气态路易氏剂等对眼和呼吸道有刺激作用的毒剂相鉴别。
预防与救治
（一）预防
迅速戴防毒面具或简易防护器材。注意不要因已有刺激症状误认为面具失效而脱掉面具。呕吐物和分泌物较多时，可暂时屏住呼吸；闭眼、迅速脱下面罩，擦净，然后再戴上。
（二）救治
1．呼吸道：上呼吸道有刺激症状时，可吸入抗烟剂（氯仿40ml、酒精40ml、乙醚20ml、氨水5～10滴，分装成100支安瓿、每支1ml）每次 吸入1～2支，5～10分钟后再吸入，不宜多用。头痛、牙痛可服止痛片。疼痛难忍时，皮下注射吗啡。出现肺水肿时，按窒息性毒剂中毒处理。
2．眼：毒剂微粒进入眼内时，切勿用手揉擦。应立即用清水或2％碳酸氢钠溶液充分冲洗。有结膜炎及角膜炎时，可按眼科治疗原则处理。
3．皮肤：先用干布或棉花轻轻擦去毒剂，再用肥皂水或净水冲冼。有条件时可用6％碳酸氢钠或3％碳酸钠溶液冲冼。不要开始就用水洗，否则皮肤刺痛会加 重。局部炎症用可的松冷霜涂抹。皮肤痛痒，口服苯海拉明20～50mg，每天3～4次。水疱破裂时，注意预防感染。较深的Ⅱ度化学性烧伤，按一般烧伤处 理。
4．消化道：可催吐、洗胃、口服活性炭粉吸附毒剂，而后导泻。胃肠道症状明显或腹痛剧烈者，可给颠茄浸膏片或阿托品。
5．全身吸收中毒：DM含砷，吸收后有砷中毒症状者可用二巯基类抗砷药（参见路易氏剂中毒治疗）。
2006-12-16
QD 内置电池报废修理
Nokia稍微不太廉价的手机里面都有个微型充电电池。当这个电池是新的时候能撑若干个小时，但是一两年之后Nokia这个廉价电池就是发生泄漏，看下面那个被绿汤腐蚀得乱七八糟的电池。
这么小的已经报废的电池空载电压居然在2V以上，这么看来貌似是3.6V的锂电池。由于没地方买这个东西，随意找了个报废显卡上的100u电容来顶替，就是时间太短了，只能撑40秒。
这么小的已经报废的电池空载电压居然在2V以上，这么看来貌似是3.6V的锂电池。由于没地方买这个东西，随意找了个报废显卡上的100u电容来顶替，就是时间太短了，只能撑40秒。
2006-11-14
DIY Kenwood-71A 电池
天下有很多花钱买不到的东西-- Kenwood业余对讲机的配件就是一例。电池是最便宜的工业品拼的，没有任何保障。手持麦克风的线路居然没屏蔽，导致大功率发射容易锁死。
先看看电池吧，这个保险多了，用原来的电池盒子改造的。
先看看电池吧，这个保险多了，用原来的电池盒子改造的。
2006-11-12
71A手台的使用技巧
滑翔伞俱乐部的Kenwood TH-G71A的拥有量非常大，而其中有一些机器的设置不太正确，平时看不出来区别，但是在远距离着陆后通讯时候恐怕会影响通讯效果，所以特别提示大家一下。
小心烂电池
据考证在国内是没有Kenwood业余机原装电池的，市场上都是粗糙的自制电池，由于国内HAM傻子多，导致市场价格变态竞争，最终这个HAM的热衷型号71A的电池都是最便宜的劣质工业电池攒出来的，价格要多低有多低。懂行的人都知道电池的容量要靠仪器或者设备连续消耗计时来测，而不是依靠电池上的标号，在国际高水平制造公司（如三洋）刚刚解决AA电池2000mAh级别品质控制的时候，工业电池标称已经远远超过了2600mAh，中国农民HAM总是乐忠于看电池上的字然后谈论电池能用多少“天”~~如同农民看着月亮种地一样。
言归正传，被农民HAM摧毁的市场上购买的电池实际容量多在标称容量的一半以下而且寿命奇短。所以。。。。自求多福吧，不行就多带几块。
频率要正确
频率要正确飞人俱乐部的频率设定在 XXX.0625（不是XXX.0620）。偏频会导致你在远距离时无法与伙伴或教练沟通。正确的设置方法是将步进调节到12.5；
步骤：
[VFO 键]
［F键］
［MHz键］
然后用拨轮调节步进找到合适的步进12.5
[MHZ键]
保持发射功率正确
其实大多数时间都是教练在说话，大家很少发言，所以将发射功率保持在最大可以保证紧急情况下的有效沟通。在天空中对话用小功率足以四通八达，而且不会干扰高度表。可一但降落到山沟里小功率就不行了，这时候必须换成最大功率尝试通联。 G71A的发射功率3档可调，在显示屏最左侧可以看到；
[HI] －－ 大 2瓦~5瓦
[LO] －－ 小 0.5瓦
[EL] －－ 经济 50毫瓦
建议大家通过反复按LOW按钮调整频率到0.5瓦--就是LOW，这个功率在空中可以发十公里乃至数十公里。但是在地面的话就只有2公里的距离。所以在地面行进或回收时，请切换回Hi 发射。
检查电池 前面有几起案例－－在天上没电了，要么是说不出去话要么干脆什么也听不到。
G71A检查电池的办法很简单，用大功率发射2秒钟，如果屏幕最下方有个格子组成的黑条，如果显示7格表明电量充足，如果只有5格就说明电量不足，如果少于5格则表明随时可能断电。在越野飞行或者比赛前为了绝对保险可以使用71A随机配送的电池盒，使用前装满4节崭新的碱性5＃干电池，各位也可以随身带着这个盒子以备不时之需。
对讲机莫名其妙长发
飞行场地经常有人长发（MIC按着却不说话）。长发的人自己不知道，别人也插不了话。一般长发者都配备了某种台湾产手咪。 很多人怀疑是手咪坏了，但落地后手咪又好好的，故障又消失了。
经过试验，其实造成这一问题的主要原因出在仿造的KNEWOOD品牌的国产垃圾手咪上。原因不是手咪坏了，而是用料粗糙。由于没有采用屏蔽线，所以手咪在高功率下发射的情况下很容易被强辐射干扰，导致发射锁定。
试验的办法很简单，您把手台调到高功率，把手咪的线用各种姿势缠绕在天线上，反复按下发射键………看看是不是有锁死的现象，如果有的话，要么扔了这个手咪，要么你永远用Low发射。
听天气预报
各地机场都通过AM方式在127MHz附近播报及其详细的天气状况，比如北京首都机场就是用调幅模式在127.600MHz播报天气实况。71A此时毫无疑问是最合适的收音机。
(这篇最早发表在飞人论坛，无奈论坛管理无章丢失文章无数。最近居然在户外网站上给找回来了，当然是被流氓编辑偷去当自己的文章了。）
小心烂电池
据考证在国内是没有Kenwood业余机原装电池的，市场上都是粗糙的自制电池，由于国内HAM傻子多，导致市场价格变态竞争，最终这个HAM的热衷型号71A的电池都是最便宜的劣质工业电池攒出来的，价格要多低有多低。懂行的人都知道电池的容量要靠仪器或者设备连续消耗计时来测，而不是依靠电池上的标号，在国际高水平制造公司（如三洋）刚刚解决AA电池2000mAh级别品质控制的时候，工业电池标称已经远远超过了2600mAh，中国农民HAM总是乐忠于看电池上的字然后谈论电池能用多少“天”~~如同农民看着月亮种地一样。
言归正传，被农民HAM摧毁的市场上购买的电池实际容量多在标称容量的一半以下而且寿命奇短。所以。。。。自求多福吧，不行就多带几块。
频率要正确
频率要正确飞人俱乐部的频率设定在 XXX.0625（不是XXX.0620）。偏频会导致你在远距离时无法与伙伴或教练沟通。正确的设置方法是将步进调节到12.5；
步骤：
[VFO 键]
［F键］
［MHz键］
然后用拨轮调节步进找到合适的步进12.5
[MHZ键]
保持发射功率正确
其实大多数时间都是教练在说话，大家很少发言，所以将发射功率保持在最大可以保证紧急情况下的有效沟通。在天空中对话用小功率足以四通八达，而且不会干扰高度表。可一但降落到山沟里小功率就不行了，这时候必须换成最大功率尝试通联。 G71A的发射功率3档可调，在显示屏最左侧可以看到；
[HI] －－ 大 2瓦~5瓦
[LO] －－ 小 0.5瓦
[EL] －－ 经济 50毫瓦
建议大家通过反复按LOW按钮调整频率到0.5瓦--就是LOW，这个功率在空中可以发十公里乃至数十公里。但是在地面的话就只有2公里的距离。所以在地面行进或回收时，请切换回Hi 发射。
检查电池 前面有几起案例－－在天上没电了，要么是说不出去话要么干脆什么也听不到。
G71A检查电池的办法很简单，用大功率发射2秒钟，如果屏幕最下方有个格子组成的黑条，如果显示7格表明电量充足，如果只有5格就说明电量不足，如果少于5格则表明随时可能断电。在越野飞行或者比赛前为了绝对保险可以使用71A随机配送的电池盒，使用前装满4节崭新的碱性5＃干电池，各位也可以随身带着这个盒子以备不时之需。
对讲机莫名其妙长发
飞行场地经常有人长发（MIC按着却不说话）。长发的人自己不知道，别人也插不了话。一般长发者都配备了某种台湾产手咪。 很多人怀疑是手咪坏了，但落地后手咪又好好的，故障又消失了。
经过试验，其实造成这一问题的主要原因出在仿造的KNEWOOD品牌的国产垃圾手咪上。原因不是手咪坏了，而是用料粗糙。由于没有采用屏蔽线，所以手咪在高功率下发射的情况下很容易被强辐射干扰，导致发射锁定。
试验的办法很简单，您把手台调到高功率，把手咪的线用各种姿势缠绕在天线上，反复按下发射键………看看是不是有锁死的现象，如果有的话，要么扔了这个手咪，要么你永远用Low发射。
听天气预报
各地机场都通过AM方式在127MHz附近播报及其详细的天气状况，比如北京首都机场就是用调幅模式在127.600MHz播报天气实况。71A此时毫无疑问是最合适的收音机。
(这篇最早发表在飞人论坛，无奈论坛管理无章丢失文章无数。最近居然在户外网站上给找回来了，当然是被流氓编辑偷去当自己的文章了。）
2006-10-30
信任危机：主伞钩因金属疲劳而折断
信任危机：主伞钩因金属疲劳而折断
作者：拷贝猫
AustriAlpin 一家著名奥地利的"小五金"公司，他所生产的金属锁扣和伞钩占据了悬挂滑翔的大半壁江山。我们所使用的AustriAlpin主伞钩大多是铝制材料制造的Parafly ，这个伞钩就是本文的重点。
PS:传闻当年引发朝鲜战争的祸根，就是一把奥地利制造的铁锹在边境冲突中打死了人。
最近几年间，这家公司所生产的最受人民欢迎的产品，却出现了一些小问题。
2001年，一个DHV近些年来用来作DHV测试飞行的AustriAlpin主伞钩在起飞时刻断了………
从2003年开始，一个捷克人报告在起飞时伞钩突然间断裂。调查不了了之，调查结论是这个捷克人在未关闭伞钩门的情况下过载使用伞钩。（锁紧后每把伞钩的拉断的力量是超过1.5~1.8吨），可以吊个汽车了。
报告的伞钩断裂
但是随后类似的报告越来越多：
加拿大Denis Roumiantsev报告的事故主伞钩。
关注这事的人知道，事情闹大后，在2005.3 DHV以AustriAlpin未能按时出具疲劳测试报告的情况下，通告全世界全面禁止AustriAlpin钩的悬挂滑翔使用。随后2005.6月AustriAlpin提交报告声称他们的钩子没有问题。DHV在6月发部了解除警告。
诡异的是，在今天的DHV网站上，解除警告不见了，停用警告依然存在。而生产厂商AustriAlpin的拳头产品--铝制主伞钩从AustriAlpin的网站消失了，仅留下了原来推荐双人伞使用的钢质钩PowerFly~~
关于那个史上著名的捷克断钩的结论仍然存在很大争议。生产商对于伞钩断裂的解释是，在OpenGate的情况下，过载造成伞钩断裂。但是反对者持不同意见：
断裂事故报告中的主伞钩
AustriAlpin的反对者提醒大家注意，断裂面有一个平滑的撕裂面。
破坏性试验后的主伞钩
在试验室中，在不锁闭的情况下，被测试机器拉断的钩子，其表面呈现另外的样子。
外行看热闹，至于金属断裂面的具体情况，还得请相关专家来评判了。我们只能在脑子里放个问号而已。
随后DHV进行了更大范围的调查，发现疲劳测试中却发现了另一个惊人的故事。这个问题波及到了许多许多的钩子，不仅仅是AustriAlpin。
疲劳测试中每个伞钩负载几十KG，这点份量远远达不到拉断的程度（1.5 吨），但是由于制造精度的原因，伞钩关闭后上下钩咬合部分有0.2~2.5mm的缝隙。如果这个咬合缝隙所造成的形变大于金属疲劳形变的门限，那么钩子无论是否锁 闭，都会导致金属疲劳。在反复的加载和卸掉几十KG力的情况下，会导致出现金属疲劳导致的断裂。Aluminium as well as steel karabiners can be affected.。DHV特别指出无论是铝制品还是钢制品，都将受到金属疲劳影响。
DHV给我们的建议是，如果你在安装伞带的时候，需要用力按才能将扣子合上，那么你的主伞钩已经变形，需要立刻更换主伞钩。
整个滑翔伞世界陷入了一场信心危机当中，很多人用伞绳自制了第二保险锁，从今年PWC世界冠军的主伞钩使用了德国的 Charly Pinlock穿轴式伞钩，有人干脆用最普通的螺旋钢伞钩--就是我们连接副伞的那个。另外一些企业不失时机地推出了制式保险绳索，以实现大家Double伞钩的愿望^^。
好了，最后，DHV的相关测试机构给大家指出一条明路，来测试你的主伞钩咬合点Fk是否会影响其寿命。
先看一下每一个主伞钩的粗略测试数据，其中Fou是可以造成金属疲劳的拉力。Fk是测试机构采样测试中的伞钩锁咬合所需拉力。如果你的伞钩的Fk 〉Fou，那么，请立刻停止使用你的伞钩，因为你的伞钩无论上锁与否，都将发生金属疲劳。
测试方法：
1. 将伞钩悬挂在一个结实的地方。
2. 用一个家用体重计或更精准的称，按照上表中数据，给你的坐袋填充负重。负重就是Fk，如果你用铝制的Supair Alu，那么你需要准备少于70KG的坐袋+配重。如果你用铝制AustriAlpin，你需要25KG以内的配重。
3. 悬挂配种的方法如图2，3所示，距离中心点1厘米，这正是DHV测试的方法。
4. 如果配重Fk导致伞钩闭合，那么你将很难将其打开，如果此时的Fk没有超过疲劳拉力Fo，那么你的伞钩是安全的。
DHV安全警告:
http://www.dhv.de/typo/Safety_Notes.3939.0.html
--------------------------------------------
Airworthiness advisory
Paraglider harness, harnesscarabiner Parafly Automatic from AustriAlpin
After several fractures of aluminium harnesscarabiner Parafly Automatic from AustriAlpin during use in 2003 and 2004, the manufacturer was asked to prove fatigue strength against vibration. The last deadline was 1. March 2005. This proof has not been shown up today. Tests conducted in the order of DHV to aluminium harnesscarabiner Parafly Automatic from AustriAlpin showed low values of fatigue strength against vibration. The in flight safety is gravely affected. The DHV has decided on the following precautionary safety measure:
All harness carabiners Parafly Automatic by Austrialpin, must not be used any more.
The airworthiness instruction comes into effect with the publishing of the NFGH (Paraglider and Hanglider news).
Gmund, 09.03.2005
Klaus Tänzler
Managing Director
-----------------------------------------------------------------------------------
Safety note
Paraglider harness, Hangglider harness karabiners Finsterwalder GmbH
Investigations by the DHV and the company Finsterwalder GmbH have shown that many paraglider- and hangglider karabiners are not fatigue resistant below the point of actuation by gravity of their catch. Aluminium as well as steel karabiners can be affected.
Harness karabiners with conventional catch fasteners show different fatigue resistance over and below the point of actuation by gravity of their catch. The point of actuation by gravity has not been investigated by the karabiner manufacturers and is subject to an unknown tolerance range.
Endangered above all, are those karabiners, by which the point of actuation by gravity in the fastening catch occurs by a loading (Fk) that is larger than the fatigue strength (Fou) - reduced by 20% - established for the fatigue strength with open catch by the least favourable harness arrangement. By these karabiners, load oscillation tensions can arise on the inner bends of the karabiner, which are greater than the fatigue strength of the material. The reduction of 20% is a result of the safety coefficient of 1.2 with which the fatigue strength must be provided in order to take account of fluctuations in material and finishing. There is no warning before a breakage due to metal fatigue, as pronounced deformation does not occur, and is therefore not recognisable.
A karabiner fastener is "actuated by gravity" when there is no play present in the fastener. Karabiners with catch fasteners exhibit "catch play" from 0.2 mm to 2.5 mm. "Actuation by gravity" first occurs when the catch play is reduced to zero by deformation as a result of loading (Fk).
The point of actuation by gravity Fk can be roughly established by every pilot by testing the size of the load at which the karabiner fastener can still be easily opened.
The DHV has requested the karabiner manufacturers to establish and announce exact values for the fatigue strength Fou by March 1st 2005. This deadline has now been extended to the middle of April.
Endangered karabiners as defined above are not airworthy.
The Finsterwalder GmbH therefore takes the following precautionary safety measure:
It is recommended to use only karabiners whose fatigue resistance has been verified.
Munich, February 2005
Dipl. Ing. Thomas Finsterwalder
Managing director Finsterwalder GmbH
Finsterwalder GmbH, Pagodenburgstr.8, 81247 München, Tel. ++49 (0)89 811 65 28,
Web www.finsterwalder-charly.de .
作者：拷贝猫
AustriAlpin 一家著名奥地利的"小五金"公司，他所生产的金属锁扣和伞钩占据了悬挂滑翔的大半壁江山。我们所使用的AustriAlpin主伞钩大多是铝制材料制造的Parafly ，这个伞钩就是本文的重点。
PS:传闻当年引发朝鲜战争的祸根，就是一把奥地利制造的铁锹在边境冲突中打死了人。
最近几年间，这家公司所生产的最受人民欢迎的产品，却出现了一些小问题。
2001年，一个DHV近些年来用来作DHV测试飞行的AustriAlpin主伞钩在起飞时刻断了………
从2003年开始，一个捷克人报告在起飞时伞钩突然间断裂。调查不了了之，调查结论是这个捷克人在未关闭伞钩门的情况下过载使用伞钩。（锁紧后每把伞钩的拉断的力量是超过1.5~1.8吨），可以吊个汽车了。
报告的伞钩断裂
但是随后类似的报告越来越多：
加拿大Denis Roumiantsev报告的事故主伞钩。
关注这事的人知道，事情闹大后，在2005.3 DHV以AustriAlpin未能按时出具疲劳测试报告的情况下，通告全世界全面禁止AustriAlpin钩的悬挂滑翔使用。随后2005.6月AustriAlpin提交报告声称他们的钩子没有问题。DHV在6月发部了解除警告。
诡异的是，在今天的DHV网站上，解除警告不见了，停用警告依然存在。而生产厂商AustriAlpin的拳头产品--铝制主伞钩从AustriAlpin的网站消失了，仅留下了原来推荐双人伞使用的钢质钩PowerFly~~
关于那个史上著名的捷克断钩的结论仍然存在很大争议。生产商对于伞钩断裂的解释是，在OpenGate的情况下，过载造成伞钩断裂。但是反对者持不同意见：
断裂事故报告中的主伞钩
AustriAlpin的反对者提醒大家注意，断裂面有一个平滑的撕裂面。
破坏性试验后的主伞钩
在试验室中，在不锁闭的情况下，被测试机器拉断的钩子，其表面呈现另外的样子。
外行看热闹，至于金属断裂面的具体情况，还得请相关专家来评判了。我们只能在脑子里放个问号而已。
随后DHV进行了更大范围的调查，发现疲劳测试中却发现了另一个惊人的故事。这个问题波及到了许多许多的钩子，不仅仅是AustriAlpin。
疲劳测试中每个伞钩负载几十KG，这点份量远远达不到拉断的程度（1.5 吨），但是由于制造精度的原因，伞钩关闭后上下钩咬合部分有0.2~2.5mm的缝隙。如果这个咬合缝隙所造成的形变大于金属疲劳形变的门限，那么钩子无论是否锁 闭，都会导致金属疲劳。在反复的加载和卸掉几十KG力的情况下，会导致出现金属疲劳导致的断裂。Aluminium as well as steel karabiners can be affected.。DHV特别指出无论是铝制品还是钢制品，都将受到金属疲劳影响。
DHV给我们的建议是，如果你在安装伞带的时候，需要用力按才能将扣子合上，那么你的主伞钩已经变形，需要立刻更换主伞钩。
整个滑翔伞世界陷入了一场信心危机当中，很多人用伞绳自制了第二保险锁，从今年PWC世界冠军的主伞钩使用了德国的 Charly Pinlock穿轴式伞钩，有人干脆用最普通的螺旋钢伞钩--就是我们连接副伞的那个。另外一些企业不失时机地推出了制式保险绳索，以实现大家Double伞钩的愿望^^。
好了，最后，DHV的相关测试机构给大家指出一条明路，来测试你的主伞钩咬合点Fk是否会影响其寿命。
先看一下每一个主伞钩的粗略测试数据，其中Fou是可以造成金属疲劳的拉力。Fk是测试机构采样测试中的伞钩锁咬合所需拉力。如果你的伞钩的Fk 〉Fou，那么，请立刻停止使用你的伞钩，因为你的伞钩无论上锁与否，都将发生金属疲劳。
测试方法：
1. 将伞钩悬挂在一个结实的地方。
2. 用一个家用体重计或更精准的称，按照上表中数据，给你的坐袋填充负重。负重就是Fk，如果你用铝制的Supair Alu，那么你需要准备少于70KG的坐袋+配重。如果你用铝制AustriAlpin，你需要25KG以内的配重。
3. 悬挂配种的方法如图2，3所示，距离中心点1厘米，这正是DHV测试的方法。
4. 如果配重Fk导致伞钩闭合，那么你将很难将其打开，如果此时的Fk没有超过疲劳拉力Fo，那么你的伞钩是安全的。
DHV安全警告:
http://www.dhv.de/typo/Safety_Notes.3939.0.html
--------------------------------------------
Airworthiness advisory
Paraglider harness, harnesscarabiner Parafly Automatic from AustriAlpin
After several fractures of aluminium harnesscarabiner Parafly Automatic from AustriAlpin during use in 2003 and 2004, the manufacturer was asked to prove fatigue strength against vibration. The last deadline was 1. March 2005. This proof has not been shown up today. Tests conducted in the order of DHV to aluminium harnesscarabiner Parafly Automatic from AustriAlpin showed low values of fatigue strength against vibration. The in flight safety is gravely affected. The DHV has decided on the following precautionary safety measure:
All harness carabiners Parafly Automatic by Austrialpin, must not be used any more.
The airworthiness instruction comes into effect with the publishing of the NFGH (Paraglider and Hanglider news).
Gmund, 09.03.2005
Klaus Tänzler
Managing Director
-----------------------------------------------------------------------------------
Safety note
Paraglider harness, Hangglider harness karabiners Finsterwalder GmbH
Investigations by the DHV and the company Finsterwalder GmbH have shown that many paraglider- and hangglider karabiners are not fatigue resistant below the point of actuation by gravity of their catch. Aluminium as well as steel karabiners can be affected.
Harness karabiners with conventional catch fasteners show different fatigue resistance over and below the point of actuation by gravity of their catch. The point of actuation by gravity has not been investigated by the karabiner manufacturers and is subject to an unknown tolerance range.
Endangered above all, are those karabiners, by which the point of actuation by gravity in the fastening catch occurs by a loading (Fk) that is larger than the fatigue strength (Fou) - reduced by 20% - established for the fatigue strength with open catch by the least favourable harness arrangement. By these karabiners, load oscillation tensions can arise on the inner bends of the karabiner, which are greater than the fatigue strength of the material. The reduction of 20% is a result of the safety coefficient of 1.2 with which the fatigue strength must be provided in order to take account of fluctuations in material and finishing. There is no warning before a breakage due to metal fatigue, as pronounced deformation does not occur, and is therefore not recognisable.
A karabiner fastener is "actuated by gravity" when there is no play present in the fastener. Karabiners with catch fasteners exhibit "catch play" from 0.2 mm to 2.5 mm. "Actuation by gravity" first occurs when the catch play is reduced to zero by deformation as a result of loading (Fk).
The point of actuation by gravity Fk can be roughly established by every pilot by testing the size of the load at which the karabiner fastener can still be easily opened.
The DHV has requested the karabiner manufacturers to establish and announce exact values for the fatigue strength Fou by March 1st 2005. This deadline has now been extended to the middle of April.
Endangered karabiners as defined above are not airworthy.
The Finsterwalder GmbH therefore takes the following precautionary safety measure:
It is recommended to use only karabiners whose fatigue resistance has been verified.
Munich, February 2005
Dipl. Ing. Thomas Finsterwalder
Managing director Finsterwalder GmbH
Finsterwalder GmbH, Pagodenburgstr.8, 81247 München, Tel. ++49 (0)89 811 65 28,
Web www.finsterwalder-charly.de .
2006-10-23
[Archive] Paragliders, designed by man or machine?
Bruce Goldsmith
Sometimes people ask me why I need to spend so much time designing paragliders when we now have computer programs that can design paragliders for you. The question actually shows a lack of understanding of the whole design process and the role of computers within it. I hope this article will help everyday pilots understand how paragliders are actually designed.
How it works
A modern paraglider is so complex that it's not really possible to design one without a sophisticated design program. This is because there are so many design parameters involved, all of which are interrelated in three dimensions. There are also a huge number of components in a paraglider.
The design program usually starts with the designer deciding on his new creation's planform and aerodynamic profile, but of course there are many more parameters than that. As an example, a typical 50 cell intermediate glider will have around 200 lines, and each line needs to be accurate in length to within millimetres. The canopy will have 400 different panels, each one with a unique shape that has to be carefully calculated.
Gliders are of course symmetrical in design, so there are actually only around 200 different individual panels as the two sides are simply mirror images of each other. But some colour schemes are asymmetrical, such as Airea's for instance. All this detailed repetitive number crunching is what computers are so good at, and is why they have become an essential part of designing a paraglider.
But this is just the start. After making the first prototype, the designer and his test pilots then test fly the glider to see if the design concept works. This is the tricky part, because each design has literally hundreds of different parameters, and the designer has to decide which of the parameters he needs to change to improve the design. The prototype is then modified and test-flown again and again with different modifications. Usually several prototypes are needed until the designer achieves his goal.
Design software
Most paraglider design software works using AutoCAD itself and is actually a bolt-on addition to AutoCAD. Others work independently as stand alone software. It's actually possible to design a paraglider just using AutoCAD. Some companies do this, but it can be quite time-consuming.
The first thing to grasp about all these design programs is that they're geometric models. This means that the program models the shape of the paraglider in three-dimensional space, t enabling the designer to create the shape of glider he wants. But the program doesn't calculate what that shape should be. That's down to the skill of the designer. It's all quite similar to the way an architect designs a building. The CAD program helps him create the shape he wants, but doesn't design the building for him. The similarity with engineering goes further than this. The design program doesn't tell you if the glider is going to be a good one or a bad one once it is completed. Just like the architect, his program doesn't tell him if the building will be successful once built.
This is why the test flying of paragliders is such an important part of any R+D program. It's the test flying which tells the designer if he is on the right track or not. There are some flow analysis programs that can help the designer, but there's no substitute for actually flying the glider.
What's available
Many paraglider companies have developed their own software, and there are even some commercially available software packages on sale. Normal retail price for one of these design packages is in the region of 10 000 euros, though this price does change depending on what's included in the package. For instance, some packages also require you to have AutoCAD to run the program on.
Several companies like Nova, Airwave, Advance and Pro-Design have their own exclusive design software. These programs are the property of the paragliding company that has designed them and are closely guarded secrets.
Commercially available packages
Some enterprising computer programmers have written paraglider design programs that can be purchased by any company or individual.
'LT Paraglide' is a new paraglider design program on the market from ex-Freex designer Rasso von Schlichtegroll, but it's not yet used by any paraglider manufacturer. The program is in German, but Rasso is writing an English version that should be released in October 2003.
If you're a budding designer you might want to contact Rasso on info@living-things.net.
Michael Nesler is a German paraglider designer and programmer who lives in Bolzano, Italy. His software, 'FlyCad FD' is an application for AutoCAD, written in C++ and AutoLisp, and it can be used to design paragliders, kites, balloons, airships and even inflatable boats. It's used by his own company Independence, as well as Swing, Firebird, Edel, Perche, Airea, Wings of Change and Windtech.
Last year I visited Karel Vrbensky in his top floor apartment in Prague, the capital of the Czech Republic. Karel originally developed his program, 'PG Design', for Mac paragliders. They decided that by selling the software to several manufacturers they could spread the ongoing development costs of the program. Mac now resell PG Design to several clients, including Edel and Gradient.
Sometimes people ask me why I need to spend so much time designing paragliders when we now have computer programs that can design paragliders for you. The question actually shows a lack of understanding of the whole design process and the role of computers within it. I hope this article will help everyday pilots understand how paragliders are actually designed.
How it works
A modern paraglider is so complex that it's not really possible to design one without a sophisticated design program. This is because there are so many design parameters involved, all of which are interrelated in three dimensions. There are also a huge number of components in a paraglider.
The design program usually starts with the designer deciding on his new creation's planform and aerodynamic profile, but of course there are many more parameters than that. As an example, a typical 50 cell intermediate glider will have around 200 lines, and each line needs to be accurate in length to within millimetres. The canopy will have 400 different panels, each one with a unique shape that has to be carefully calculated.
Gliders are of course symmetrical in design, so there are actually only around 200 different individual panels as the two sides are simply mirror images of each other. But some colour schemes are asymmetrical, such as Airea's for instance. All this detailed repetitive number crunching is what computers are so good at, and is why they have become an essential part of designing a paraglider.
But this is just the start. After making the first prototype, the designer and his test pilots then test fly the glider to see if the design concept works. This is the tricky part, because each design has literally hundreds of different parameters, and the designer has to decide which of the parameters he needs to change to improve the design. The prototype is then modified and test-flown again and again with different modifications. Usually several prototypes are needed until the designer achieves his goal.
Design software
Most paraglider design software works using AutoCAD itself and is actually a bolt-on addition to AutoCAD. Others work independently as stand alone software. It's actually possible to design a paraglider just using AutoCAD. Some companies do this, but it can be quite time-consuming.
The first thing to grasp about all these design programs is that they're geometric models. This means that the program models the shape of the paraglider in three-dimensional space, t enabling the designer to create the shape of glider he wants. But the program doesn't calculate what that shape should be. That's down to the skill of the designer. It's all quite similar to the way an architect designs a building. The CAD program helps him create the shape he wants, but doesn't design the building for him. The similarity with engineering goes further than this. The design program doesn't tell you if the glider is going to be a good one or a bad one once it is completed. Just like the architect, his program doesn't tell him if the building will be successful once built.
This is why the test flying of paragliders is such an important part of any R+D program. It's the test flying which tells the designer if he is on the right track or not. There are some flow analysis programs that can help the designer, but there's no substitute for actually flying the glider.
What's available
Many paraglider companies have developed their own software, and there are even some commercially available software packages on sale. Normal retail price for one of these design packages is in the region of 10 000 euros, though this price does change depending on what's included in the package. For instance, some packages also require you to have AutoCAD to run the program on.
Several companies like Nova, Airwave, Advance and Pro-Design have their own exclusive design software. These programs are the property of the paragliding company that has designed them and are closely guarded secrets.
Commercially available packages
Some enterprising computer programmers have written paraglider design programs that can be purchased by any company or individual.
'LT Paraglide' is a new paraglider design program on the market from ex-Freex designer Rasso von Schlichtegroll, but it's not yet used by any paraglider manufacturer. The program is in German, but Rasso is writing an English version that should be released in October 2003.
If you're a budding designer you might want to contact Rasso on info@living-things.net.
Michael Nesler is a German paraglider designer and programmer who lives in Bolzano, Italy. His software, 'FlyCad FD' is an application for AutoCAD, written in C++ and AutoLisp, and it can be used to design paragliders, kites, balloons, airships and even inflatable boats. It's used by his own company Independence, as well as Swing, Firebird, Edel, Perche, Airea, Wings of Change and Windtech.
Last year I visited Karel Vrbensky in his top floor apartment in Prague, the capital of the Czech Republic. Karel originally developed his program, 'PG Design', for Mac paragliders. They decided that by selling the software to several manufacturers they could spread the ongoing development costs of the program. Mac now resell PG Design to several clients, including Edel and Gradient.
2006-10-18
[Archive] 滑翔伞材料研究
| Colour and Fabrics We all want our paragliders to stay air tight, have beautiful colors and last a long time. The fabric and paraglider manufacturers consider this and more. Everybody has heard stories of gliders made from bad materials. Some gliders became porous prematurely while others seem to fade with every flight. These problems have been nearly eliminated with the thorough, constant testing of paraglider sailcloth. Textile mills constantly evaluate the fabric for porosity, stretch, weight and aging characteristics. The aging factors break down into color, UV, fatigue, abrasion and humidity resistance. The choice of fabric is one of the biggest decision's a paraglider designer face. Textile mills supplying the paragliding industry include: Gelvenor, Toray (Edel, Swing, Trekking, XIX), Porcher Marine, and Perserveance (Swing). Sofifly is set to enter the market with Swing using their materials. Porcher Marine dominates the market. Over 70% of all the gliders made use their materials. GELVENOR - #1 is the best (Aerodyne, Aeros, Airwave, Apco, Nova, Ozone, Sol) #1 Purple, Dark Green, Red, Dark Blue, White #2 Yellow, Violet (Light Purple), Turquoise #3 Orange, Fluorescent Green, Fluorescent Pink, Fluorescent Yellow PORCHER - 5-6 is the best (Advance, Aerodyne, Airwave, Firebird, FreeX, Gin, Gradient, Independence, ITV, MacPara, Nova, Ozone, Paratech, Perche, Pro Design, Sky, Skywalk, Sol, UP, U-Turn, Windtech, Wings of Change) (from Porcher Marine) 5-6 Black, Deep Blue, Gold, Sunflower (Yellow), Dragon Red 5 Light Blue, Lhotse (Purple), Red, Grepon (Magenta) 4 White, Parma (Lilac), Orange 3-4 Lagoon (Light Green), Turkis (Turquoise), Grey 2-3 Dark Green 2 Prairie (Fluorescent Green) 1 Fluorescent Yellow All of these fabric characteristics are interrelated. Improving one characteristic only comes at the expense of another. There is always the need to reach a compromise. For example, a heavier cloth will have better aging characteristics but at the expense of extra weight. The additional weight will cause a glider to have a slower and more dynamic recovery from a collapse. Designers generally use materials weighing 42-46 g/m2. One of the latest trends is for some gliders to incorporate a 36-38 g/m2 material for the bottom surface and cell walls. The lighter material eliminates the extra weight associated with V-rib technology. Some older gliders used a laminated 55 g/m2 mylar fabric on the leading edge and top surface. Nylon is the most commonly used raw fiber for the manufacture of sailcloth. The properties of nylon include excellent strength, flexibility, abrasion resistance, ease of drying and resistance to attack by insects and microorganisms. Teijin alone uses polyester for their sailcloth. Polyester fabrics are more resistant to shrinking and stretching, dry quicker and less prone to wrinkle and crease. Used properly, both nylon and polyester have their place in paraglider construction. However, just remember that both types of material are very UV sensitive.
A key component of a materials weight is the type of finish. Choices include coating, impregnation or laminated. The finish is subsequently a vital component of porosity. A majority of paraglider materials use either a polyurethane coating (Porcher Marine, Sofifly and Toray), a silicon coating (Perserverance) or both (Gelvenor). This provides the best balance between weight, flexibility and aging. Impregnation is a special type of coating process. Dipping the material in a bath results in coating both sides of the material. Mylar materials are laminated and provide resistance to stretching, absolutely zero porosity and good resistance to aging. However, mylar popularity has declined because of the extra weight and lack of flexibility. A properly designed glider will use different materials in different areas; heavier, less porous fabrics for the top and maybe the bottom surface such as Porcher Marine 9017 or 9O92 ME or Gelvenor LCN066 OKS; Gelvenor LCN066 K54 or LCN517 K54 are intended for the bottom surface; stiffer, more porous material for the cell walls like Porcher Marine 9017 or 9O92 E29A. It is not unheard of for a glider to use up to five kinds of sailcloth. Manufacturers carefully select each material for optimum performance.
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Line Attachment points
While all certified paragliders are shock tested to 8 g’s of the maximum recommended wing loading, the line attachment points still remain a critical area of the glider. The most common method is to sew a trapezoid or a semi-circle shaped piece of mylar to the cell wall. The mylar serves three purposes: improve inflation, aid in recovery and provide a stable and reinforced platform. Manufacturers sew a piece of polyester twill tape known as the V-tab onto the mylar platform. Lines attach to the V-tabs on the bottom surface of the glider. This is the method preferred by many companies. There are two variations: one is to use regular sailcloth instead of the mylar. A newer technique is to glue the mylar to the cell wall rather than sew it.
A few companies take another approach. Rather than possibly distort the cell wall with additional stitching, these manufacturers sew the V-tabs only into the bottom surface seam. This method produces a very clean top surface. Despite shock load testing, this method doesn’t appear to be the most durable in the long run.
The most unique method eliminate the V-tabs entirely. The lines are sewn directly to the glider. Folding the end of the line over several times assures that more than a single point of stitching catches each line. The result is a very clean finish on the bottom surface and an associated reduction in drag. However, every broken line requires taking out the seam and carefully sewing it again.
On the other end of the spectrum, another method foregoes the mylar platform and attach the V-tab all the way to the top surface. Pro Design builds all of their gliders with each line attached this way. UP does so only for the "A" and "B" lines since these lines support 80% of the pilot weight. If you have ever seen a picture of the bottom surface of a UP glider you can see where the V-tabs intersect and form a series of X’s along the leading edge.
Line Meterials
There has been quite a bit of discussion lately about the types of lines used in our paragliders: Spectra vs. Kevlar. Since every distributor has their own agenda, I decided to do some research myself. All of the following information is available from textile reference books and paragliding literature.
I am not associated with proponents of either material. My old glider had Dyneema lines, my current glider has aramid and the glider I am considering next uses both.
The terms Kevlar and Aramid are used interchangeably in this article as are Spectra and Dyneema.
KEVLAR & ARAMID
Dupont developed Kevlar in 1965 and introduced it to the market in 1972. Kevlar is an aramid (aromatic polyamide) fiber. Kevlar 49 is used for reinforcing plastic composites in aircraft, sporting goods, etc. Paragliding lines use Kevlar 29. Resin impregnated Kevlar 29 is used in the "bullet proof" applications. However, Kevlar can be easily damaged by abrasive dirt particles. Several coatings or treatments such as Teflon can improve abrasion resistance. Dupont supplies raw Kevlar material to Edelrid, Eulit and FSE. Teijin produces the Technora used by Cousin. Toray uses Twaron from Akzo Nobel.
Advantages
- Three times the strength of nylon and polyester.
- Half the weight and volume of nylon.
- Can with stand high temperatures before losing strength.
- Heat resistant to 750 degrees F.
- Flame resistant.
- Low elongation.
- Resists most acids.
Disadvantages
- Poor abrasion resistance.
- Poor sunlight (UV) resistance.
- 3-13% strength lose when wet.
SPECTRA, DYNEEMA & HIGH MODULUS DYNEEMA
Spectra is the trade name for a high performance polyethylene (HPPE) fiber manufactured by Allied Signal. Dyneema is manufactured by DSM (Netherlands) and is the same material. Originally introduced in 1985, there are two versions: Spectra 900 and Spectra 1000. The original Spectra 900 has a higher elongation and can not be sewn. The Spectra 1000 was introduced to overcome these drawbacks and is used today for paragliders. The two types of Spectra are the source for the myth "that all Spectra stretches".
Advantages
- Highest strength-to-weight ratio of any fiber.
- 40% stronger than Kevlar and four times stronger than nylon.
- 7 to 20 times the abrasion resistance of Kevlar.
- Low coefficient of friction.
- High chemical resistance.
- Cut/tear resistant.
- Good UV resistance.
- Low stretch properties.
- Low weight/volume.
- Low moisture absorption.
Disadvantages
- Begins to lose strength at 230-240 degrees F.
- Difficult to sew.
- Can dramatically change length over time.
Kevlar can be distinguished by it's yellowish-beige color. While, Dyneema is always white.
So let's use a manufactures line material characteristics chart to compare lines using two different materials.
| Sleeve material | Polyester | Polyester |
| | | |
| Core material | Aramid | Dyneema |
| | | |
| Diameter in mm | 1.3 | 1.3 |
| | | |
| Weight per meters (total) g/m2 | 1.53 | 1.15 |
| Weight per meters (core) g/m2 | 0.68 | 0.46 |
| Weight per meters (sleeve) g/m2 | 0.85 | 0.69 |
| | | |
| Breaking strength min daN | 120 | 130 |
| | | |
| Effective breaking strength daN | 149 | 152 |
| | | |
| Single knot breaking strength daN | 52 | 54 |
| | | |
| Strength after 5000 bending cycles daN | 66 | 132 |
| | | |
| Elongation at | | |
| 5 daN in % | 0.1 | 0.1 |
| 10 daN in % | 0.2 | 0.2 |
| 15 daN in % | 0.3 | 0.3 |
| 20 daN in % | 0.5 | 0.5 |
| 25 daN in % | 0.6 | 0.6 |
| 50 daN in % | 1.5 | 1.1 |
| 75 daN in % | 2.2 | 1.6 |
| 100 daN in % | 2.8 | 2.2 |
| 125 daN in % | NA | 2.8 |
| | | |
| Elongation at max. breaking strength (%) | 4.0 | 3.4 |
Inevitably, the first reaction is "This information is wrong! Aramid fibers do not stretch. Dyneema does." However, all of the above data is directly from one of the major line manufacturers. This company, along with their competitors, has invested literally thousands if not millions of dollars to develop both types of lines. So why would they have a "hidden agenda" to promote one over the other? If there are any lingering doubts, it is not THAT hard to contact the manufacturers and get the information yourself. Remember without data - it's just another opinion.
So what about the Superaramid and High Modulus Aramid fibers? A quick check of Cousin’s website (www.cousin-trestec.com) shows us that the correct name is Superaram and this is Cousin’s registered tradename for their Technora Aramide lines. While chemically identical to Kevlar and Twaron (aromatic polyamide), Superaram lines have improved UV and acid resistance, better flex characteristics and 30% better abrasion resistance. High Modulus Aramid is Edelrid’s tradename for their modified aramid lines. Despite the popular rumors, neither material is a hybrid of aramid and polyethylene.
The weave, density, sheath and construction (twisting or braiding) of the lines is just as important. Unless you fly a glider with unsheathed Spectra lines, sunlight is a major factor on the aging of the lines. The polyester sheath reacts differently to UV exposure than the lines do themselves. Unlike Kevlar and Spectra, polyester materials will began to shrink when not kept under constant tension. The end result is different for each type of line. Kevlar lines will withstand the shrinkage better because of the stiffer fibers. However, the fibers themselves become more brittle as they counteract the force of the polyester shrinking. Most line shrinking and breaking problems are the result of using different materials for the core and the sheath.
Some companies use both types of lines; Kevlar for the lower set and Spectra for the upper lines. It also not uncommon for a paraglider manufacturer to use lines from more than one supplier; a trend that is also growing with paraglider sailcloth. Different lines and materials are used for each separate model of glider.
So who uses what? Here is a quick summary: Edel uses Cousin and an unknown Korean factory. Sol and UP use Cousin. Advance, FreeX and Windtech use Cousin and Liros. Nova, Skywalk and XIX use Liros. Gin, Ozone and Swing are using Edelrid and Liros. Aerodyne, Airwave, Firebird, Gradient, Independence, Icaro, ITV, MacPara. Paratech, Perche, Pro Design, Sky and Wings of Change use Edelrid exclusively. Trekking and U-Turn use Teijin. I’m not sure about Aeros, Apco, and Pilot’s Right Stuff. Of course, all of these companies are always evaluating new materials and this can change at any time.
Then to confuse us even more, some companies are engaged in a kind of name game. They don’t use the name of the line factory - they use the name of the material or material factory. For example, Technora is the name of the aramid fiber from Teijin that Cousin uses for their line construction. Other companies simply call their lines Aramid. This is the technical name for either Dupont Kevlar, Teijin Technora or Twaron from Akzo Nobel.
Some companies will use different color lines to help with set up while other companies only use lines of the same color. Paraglider designers from the "same color" school believe lines of different colors will age at different rates. It is also cheaper to have an inventory of one or two colors compared to four or five. For safety reasons, different color stabilizer (stabilo) lines are convenient.
In summary, while both types of materials have certain advantages, both Kevlar and Spectra are accepted by the DHV, SHV, AFNOR and now CEN as suitable for paragliding. Considering there is a whole lot more to buying, flying and enjoying your paraglider, the type of line material is of secondary importance.
The important thing to remember is to care for the lines and glider properly. Don't daisy chain Kevlar lines since this abrades the fibers and the damage isn't visible. Protect Spectra lines from excessive heat. Keep your paraglider out of the sun when not in use since both types of material are UV sensitive. Have your paraglider professionally inspected once a year, after each 75 hours of use or whenever you may suspect that a hard whack or sloppy ground handling may have damaged something.
Paraglider material - the history
Recently there have been a number of postings on Internet forums asking about cloth quality, life expectancy and how to tell when your glider is past its sell-by date. Steady technological progress in the 1990s has made it possible for even relatively inexperienced pilots to rack up amounts of airtime that were unthinkable in the mid 1980s when people started hill launching paragliders first started in appreciable numbers.
Back in the late 1980s, technical progress meant that paragliders rarely saw more than two or three seasons, and their performance capped the number of hours one could fly. As the 90s came & went paraglider performance improved in leaps and bounds, to the point where ordinary pilots on intermediate gliders could ride to cloudbase and thus airtime possible for such pilots went up a large magnitude of order. In the early days, there were a number of scares where paraglider material was found to have been inappropriately chosen, or suffered manufacturing defects, but as time went on these types of problems disappeared and the more common occurrence was that the glider just got worn out.
In the search for more durable craft, pilots became more aware of the materials used in the construction of their gliders. During the 1990s we heard names like Carrington, Porcher Marine, Toray, Teijin, Unitika and Gelvenor. A major milestone came when Apco announced that they would guarantee their gliders for 250 hours or 3 years. This was the first long guarantee of any sort, made headlines for both Apco and Gelvenor, the material from which those Apco gliders were made. Apco had concluded that in order to get the cloth they needed their experience and that of the cloth manufacturer had to be combined. They entered into an agreement with Gelvenor to develop a cloth which would be based on paragliding needs as defined by Apco, using Gelvenor's expertise in cloth manufacture. The resulting cloth had a silicon layer over the PU [1] coating most other fabrics used as the final finish. Gelvenor acquired a reputation for longevity and durability. The heat was on.
With diagonal ribbing, and a reduction in the number of suspension points on gliders, the glider manufacturers wanted lighter cloths for undersurfaces, greater tear strength and resistance to elongation. Other long guarantees were instituted to rival Apcos', with back up from the cloth manufacturers. Rather than just using cloth from similar aviation sports, PG manufacturers were now dictating their own requirements. With PG companies selling 500 to 3,000 gliders a year this made a large potential market for the cloth manufacturers, who needed to supply cloth to exact requirements or lose custom to competitors.
Thanks to these advances we are now in a market where a 3-year/300 hour guarantee is the norm. Nova have now once again raised the bar by offering a one year free repair for accidental damage in addition to 3 year/300hours. New materials are being developed, with longer life spans, Swing are about to release details of the extensive testing of the cloth they offer on the Astral 3. Produced by a British company, Perseverance Mills Ltd, from Burnley in Lancashire, the material is a 6.6 filament rip stop nylon with a Silicon/PU coating. A new weave/construction promises weight similar to current cloths but an improved level of tear strength and resistance to elongation. The coating prolongs the life of the material, mostly by increasing resistance to porosity with age.
With the majority of paragliding sales being repeat business to established pilots in the post boom era of the sport, the interests of the pilot and the manufacturer get closer all the time, and the progress in cloth technology is one area with clear benefits for all.
Paraglider Material - The Players
Nylon is the most commonly used raw fibre for the manufacture of sailcloth. The properties of nylon include excellent strength, flexibility, abrasion resistance, ease of drying and resistance to attack by insects and micro-organisms. Teijin alone uses polyester for their sailcloth. Polyester fabrics are more resistant to shrinking and stretching, dry quicker and less prone to wrinkle and crease. Used properly, both nylon and polyester have their place in paraglider construction. However, just remember that both types of material are very UV sensitive.
Here's a brief look at some of the major players in paragliding fabric manufacture.
Carrington Novare [UK]: Carrington are based in Dewsbury, West Yorkshire in the UK. They have been a big player in the field for a long time. However, the profile and direction of their company and its target markets is changing. They issued us with this statement:
Carrington Performance Fabrics (CPF) was purchased from the IPT group in December 2000 by the British Millerain Company. The purchase of CPF and the subsequent incorporation of Millerain's Blake's operation enables The British Millerain group of companies to offer one of the widest range of coating techniques in Europe. Over recent years the paraglider market has become increasingly competitive with the pressure from manufacturers to reduce selling price. In such conditions it has become impossible to recoup the high cost of developing new and improved products. Without a continuing product development programme the ability to service the sector becomes increasingly difficult. CPF has therefore decided that it will no longer actively develop new paraglider fabrics but will continue to offer the existing range of fabrics whilst demand remains. It is with regret that with our long association with the paraglider sector we have had to take this decision, but our development efforts have to be focused on those sectors where a positive return can be obtained from the investment of resources.
Porcher Marine/NCV [France]: French group Porcher Industries is a worldwide leader in textiles for industrial applications, specialising in mechanically and chemically transforming yarn to produce glass, carbon, aramid and synthetic fabrics as well as non-woven and coated fabrics. Founded in 1912 by the SNC PORCHER Frères [brothers], by 1950 the company had started production of textiles for technical applications. Porcher started producing fabrics for spinnakers,gliders and parachutes in the mid 1980s. The Group reached a sales figure of 660 million Euros in 2000, with 4200 employees spread out over 19 industrial sites installed in 5 countries, ensuring the Group has a worldwide commercial presence. Paragliding cloth is made by the sport department of textile division NCV [Nebon Carle-Vassoilles] as well as the other cloths they make for sailing and parachuting, and to a lesser extent ballooning, windsurfing, hang gliding and microlighting. Paragliding cloth is produced in four different weights and with three different coatings. NCV do the whole manufacturing process in house [vertical integration]: preparation, weaving, dyeing and coating. NCV Industries is a fully owned division of the Porcher Industries Group, and produces other products like airbags and fabrics for protective clothing.
Porcher have developed a new water based [as opposed to solvent based] PU coating for their 9092 fabric that seriously reduces the effects of aging on the cloth and helps it retain its visual appearance. This development has come about as a result of EU requirements for reduced solvent use & emission, as well as customer pressure for longevity of both appearance and functionality in the cloth used in paragliding. Some manufacturers like FreeX are already using this new fabric [designated E85A] in their newest gliders. A lighter weight of material is also being developed for use with this coating.
Today, Porcher is one of the biggest players in the production of fabrics for paragliders.
Gelvenor Textiles [South Africa]:
Gelvenor Textiles is a leading global producer of high technology industrial, technical and specialised fabrics. They are also involved in production of specialty apparel for sport and leisurewear, satins and other high performance outerwear fabrics like those used in the protective textiles market and in corporate/school wear.
Gelvenor Textiles (Pty) Ltd was established in 1965 as a weaver and dyer of continuous
filament lining fabrics. In 1967 the company started producing nylon fabrics for the manufacture of parachutes and other military fabrics, mainly for the Defense Force. Textured polyester weaving started in 1968 and by 1970 Gelvenor were producing a wide range of industrial base fabrics for PVC coating, woven from high tenacity Polyester yarn. The late 1980's and early 1990's saw the transformation of the business away from finished commodity products to concentrate on fabric engineering and designing fabrics for specific niche market applications.
Gelvenor's OL-KS fabric range is manufactured from HT nylon 6.6 in a double-ripstop fabric base, which is coated with silicone, and polyurethane based compounds. This finish gives the fabrics a fuller, firmer and crisper handle to allow for easier inflation of the glider without sacrificing tear strength. The finish is an extremely durable and hard wearing polymer coating which gives zero air-permeability and sufficient fabric rigidity for good aerofoil maintenance. To give added protection against ultra-violet light and dirt adherence, the fabric is further treated on both sides with UV inhibitor and soil release agents. The company is involved in continuing research into new polymer coatings for a lighter weight glider fabric as well as alternative fabrics for bottom skins and ribs.
Perseverance Mills:
Perseverance have returned to the PG market after some time away from it with a new, exclusive contract with Swing for the top surface material of the new Astral 3. They also manufacture cloths for most outdoor garments and are very active in the promotion and sponsorship of outdoor activity sports that use the products they supply cloth for. They supply a number of parachute manufacturers like Parachutes de France with cloth.
Perseverance Mills Ltd was founded in 1901 as a weaver of specialist fabrics for balloons and typewriter ribbons. Since that time the company has become a world leader in specialist leader in specialist lightweight fabrics using man made yarns for the parachute, medical, and outdoor sports industries. As a vertically integrated manufacturer Perseverance Mills has complete quality control, not only over the weaving of fabrics but also the dyeing and finishing, ensuring that their products are fit for use in the most demanding environments.
The new cloth for PG is a 6.6 filament rip stop nylon with a Silicon PU coating. It is the same weight as other cloths commonly used in paragliding which do not have the same coating. This cloth has been developed in the last two years in partnership with Swing, with whom Perseverance have an exclusive contract for the supply of the cloth.
Toray:
Toray Industries is the largest fibre and textile manufacturer in Asia. The Toray Group factories are located in Japan, Malaysia, Thailand, Indonesia, China, and The Czech Republic. Their range of textile fabrics includes active sportswear, polyester & nylon taffetas and other linings. They also handle other kinds of fabrics such as polyester/cotton, casual/sportswear fabrics and specialised applications like paragliding.
The cloth Toray produce is also nylon based, with a PU coating. Some grades are water repellent, but not water-resistant.
Toray is currently increasing its textile production overseas as well as focusing on producing more "cutting edge" fabrics such as high performance textiles from Japan.
This isn't an exhaustive list. It just gives you an idea of where your cloth comes from. With the maturity of the sport and the pace of development, expect market shares to change and new fabrics to move the goalposts.
| Reserve Parachute Comparison | |||||||
| | Model | Maximum Weight | Surface m2 | Sink Rate | Weight | Certification | Price |
| Apco | Mayday 16 | <106> | 23 | 6.3 | 4 lbs 1 oz | DHV | $415 |
| | Mayday 18 | <120> | 30 | 5.6 | 4 lbs 14 oz | SHV | $455 |
| | Mayday 20 | <160> | 37 | 5.6 | 5 lbs 15 oz | AFNOR | $515 |
| | Tandem | <200> | 47 | 5.6 | 7 lbs 2 oz | AFNOR | $615 |
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| High Energy | QS 330 | <150> | 31 | 5.45 | 4 lbs 4 oz | NO | $575 |
| | QS 440 | <200> | 41 | 5.45 | 5 lbs 4 oz | NO | $625 |
| | QS 550 | <250> | 51 | 5.45 | 6 lbs 12 oz | NO | $675 |
| | |||||||
| Metamorfosi | Conar 16 | 64-109 kgs | 22 | 4.43-5.78 | 3 lbs 11 oz | AFNOR | $650 |
| | Conar 18 | 81-138 kgs | 28 | 4.43-5.78 | 4 lbs 7 oz | AFNOR | $750 |
| | Conar 20 | 100-170 kgs | 35 | 4.43-5.78 | 5 lbs 11 oz | AFNOR | $800 |
| | Conar 22 | 121-206 kgs | 42 | 4.43-5.78 | 6 lbs 14 oz | AFNOR | $950 |
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| Sol | 33 PDA | 60-100 kgs | 33 | 4.91 | 4 lbs 3 oz | AFNOR | $530 |
| | 37 PDA | 81-138 kgs | 37 | 4.3 | 5 lbs 5 oz | AFNOR | $530 |
| | 36 CD | 75-125 kgs | 36 | 4.22 | 5 lbs 13 oz | AFNOR | $580 |
| | 40 CD | 90-145 kgs | 40 | 3.98 | 6 lbs 7 oz | AFNOR | $580 |
| | 64 CD | 140-210 kgs | 64 | 5.0 | 10 lbs 13 oz | AFNOR | $680 |
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| Sup'Air | Small | 60-80 kgs | 23.1 | 4.8 | 4 lbs 4 oz | AFNOR | $600 |
| | Medium | 80-110 kgs | 30 | 4.4 | 4 lbs 13 oz | AFNOR | $600 |
| | Large | 100-140 kgs | 37.8 | | 5 lbs 12 oz | AFNOR | $600 |
| | Tandem | 120-200 kgs | 51.6 | 4.9 | 7 lbs 11 oz | AFNOR | $800 |
| All specifications are subject to change at any time. | |||||||
Risers
All paraglider use polyester or pre-stretched nylon webbing for the risers. Stretchy risers mean a glider will not stay in trim and could result in disaster.
The risers can be assembled with a series straight stitches, a series of bar tacks or with a box stitch. Straight stitching is the simplest method since no special machinery is required. Bar tacking is very strong but stresses the material at a single point or over a limited area. Box stitching is probably the best compromise when properly done. The stitching is spread over a larger area than the other two methods. A good manufacturer will use a computerized sewing machine to guarantee consistent results for each riser.
Beyond strength, there are a couple of small things a company can do to make the product more user friendly. Individually colored risers are an added bonus for quick sorting. They are also handy for quick identification of which riser to grab for big ears, "B" line stalls and killing the glider on the ground ("C" or "D" risers).
To attach your speed bar, the best method uses matching Brummel hooks on both ends of the system. The hooks are small pieces of metal with a hole and a slot that allows two hooks to mate without catching on anything else. Brummel hooks are also handy for attaching the risers to each other after flying.
A less convenient method relies on small quick links that screw together each time and are easy to lose. Under no circumstances should a system rely on miniature snap links or small carabiners. A line can cross the gate and snag. It has and will happen again until pilots quit using them.
Quick link keepers
Quick link keepers are easy to initially ignore. They are just little pieces of plastic that keep the lines sorted and the quick links closed. My friend tells a story about flying in Grindelwald when he sees another pilot with one hand on a riser and the other hand clutching his harness. It turns out that one of his quick links unscrewed itself and started stretching and separating under the load. One hand was actually covering the open quick link and lines. The other hand was on his reserve handle!
The most effective quick link keepers are the ones that actually fit inside the links. They are easy to remove, keep the lines bunched at the top and keep the gate from loosening. Advance, Airea, Edel, Gin, ITV, Pro Design like to use these little pieces of plastic to help keep us connected to our gliders.
Other companies use a small O-shaped ring twisted into a figure-eight and slipped onto the quick link. The idea is for the ring to keep the lines from sliding around. However, it does nothing for keeping the gate closed and they are easy to wear off.
A heat-shrink plastic sheath that covered the entire quick link was popular in the past. They are great until you have to replace a line and cut the thing off. Then you have nothing.
| Paragliding Stitching | |
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| The inside of a glider slammed against the ground too hard. | |
| This area is pretty straight forward. No manufacturer or the pilot wants to have their wing blow up in mid-air! All load bearing seams require double stitching for strength and durability. Fortunately, all manufacturers do this. Some companies go the extra length to triple and quadruple stitch the seams. For non-load bearing seams such as the partial ribs used on gliders, a single line of stitching is appropriate. There is no structural need to double stitch the seam and add unnecessary costs to produce the glider. Most early paraglider manufacturers used one row of straight stitching and another row of zigzag stitching side by side. A zigzag stitch has more give and is less subject to breakage. Thread consumption is higher since the stitches lie diagonally across the fabric. The stress is not on a single line but apportioned across the span. Advance is an example of company that still believes in a straight stitch and a zigzag stitch for all seams. This maybe why they are also some of the most expensive gliders on the market. Other companies use a zigzag stitch selectively on line attach points and associated areas. Bar tacks are a type of zigzag stitch. While perceived as being very strong (they are), bar tacks also have the disadvantage of creating many needle holes and concentrating the stress in one area. Manufacturers only use small bar tacks to reinforce the most critical areas. Mylar panels on the leading edge is one particular area. Regardless of the type of stitching used, all seams should be even in length and thread tension. Incorrectly sewn gliders will have seams where the thread is loose or there is puckering of the material on one side but not the other. The large logos and color blocking on the top and bottom surfaces of many gliders can serve a hidden purpose. It is even better if the design covers the entire span. If all the panels are lined up correctly and sewn with the correct thread tension, everything should match within a tiny fraction of an inch. This is a very easy way to check the quality of construction. Some common thread sizes and specifications used in paragliding equipment:
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| Trailing Edge |
| There are essentially two options at this point of construction: taped or hemmed. A taped trailing edge is finished by a piece of polyester tape binding the full length of the glider. For durability, a manufacturer will double or zigzag stitch the tape. The seam allowances should also be consistent from edge to edge along the tape for the entire length. Taped trailing edges are the least expensive to produce while also being the easiest to repair.
Hemmed trailing edges are generally stronger and more complicated to produce than taped trailing edges. They are also more expensive. Folding the trailing edge over on to itself twice hides the raw edge of the fabric. Sewing the hemmed edge flush with the bottom surface of the glider finishes the seam. Some companies will use a reinforcing tape inserted into the fold to stabilize the seam and for additional strength. The sewing machine operator has to be extra careful at this stage since the elliptical shape of gliders can cause the fold to occur on a diagonal to the material bias. Sloppy workmanship at this point will result in an unsightly trailing edge.
Nova has started to internally fold the material on the trailing edge. The finished product has no external fold on the bottom surface and produces the cleanest separation of air at the rear of the glider. There is also no edge to catch on debris when launching. As usual, this method does not come without additional cost and complication. |
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