本帖最后由 动静之机 于 2014-7-4 00:22 编辑 " o9 y& k* K; H2 i$ m0 z V5 M
caucsaa 发表于 2014-7-3 21:33 ![]() ! b% g) t9 t' W
嗯，我们讨论的问题就是需要多大拉力，算出一个值容易，但是不知道真实情况。谁有真实测量数据？
俺模糊了滚动摩擦系数和滚阻系数概念，抱歉。: ^7 I# f- a% C
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找了一圈，还真没有找到有文字提到拉飞机究竟要多大劲的 ，+ i; _" i# s2 n7 ?" q, f
倒是有几个关于汽车轮胎阻力数据的。好在从用轮子的角度看是
: f9 ^! H9 y: |1 t' ?一回事，不妨认为是"小尺寸模型"吧。6 Z' o# c- m; h: ?4 A/ b" E
3 L5 _+ E( U; P) _: ^http://auto.howstuffworks.com/tire4.htm 这里面提到：% O. j! l) u2 c+ {2 v( M; d6 a
! Z1 z7 P0 V z| Tire Type | Coefficient of Rolling Friction | | Low rolling resistance car tire | 0.006 - 0.01 | | Ordinary car tire | 0.015 | | Truck tire | 0.006 - 0.01 | | Train wheel | 0.001 |
该文还举例说一个4000磅（1.814吨）的汽车，采用滚阻系数0.015的轮胎，滚阻60磅（27.215公斤）。
2 }2 U6 j; ?6 Q车速75码（每秒33.528米）时，所需损耗功率12马力，这些能量，大部分作用在轮胎（变形发热呗），其余在路面。
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http://hpwizard.com/tire-friction-coefficient.html 这里面有个自动表格。+ G: g1 L: \ I7 K
通过手动选择轮胎种类和路面类型，自动给出静摩擦系数和滚阻系数。8 A# o5 E" o6 g: y
可见在混凝土路面上，滚阻系数：
/ ]4 z% E# Y3 n b9 G! H自行车胎可低达0.004
) a" a/ y. z+ ] e7 n牵引胎也不过才0.03 （其静摩擦系数高达4.0，说明就是来抓地的）" n$ b$ b( N1 C7 N
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http://hyperphysics.phy-astr.gsu.edu/hbase/frict2.html#plo 这里面有段话：# p b: g% B8 f% y; P' M+ H
Rolling FrictionA rolling wheel requires a certain amount of friction so that the point of contact of the wheel with the surface will not slip. The amount of traction which can be obtained for an auto tire is determined by the coefficient of static friction between the tire and the road. If the wheel is locked and sliding, the force of friction is determined by the coefficient of kinetic friction and is usually significantly less. Assuming that a wheel is rolling without slipping, the surface friction does no work against the motion of the wheel and no energy is lost at that point. However, there is some loss of energy and some deceleration from friction for any real wheel, and this is sometimes referred to as rolling friction. It is partly friction at the axle and can be partly due to flexing of the wheel which will dissipate some energy. Figures of 0.02 to 0.06 have been reported as effective coefficients of rolling friction for automobile tires, compared to about 0.8 for the maximum static friction coefficient between the tire and the road. 。。。轮胎在路面的最大静摩擦系数0.8，（相应的）滚阻系数一般在0.02-0.06之间。
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这三组数据，和俺在6楼（0.02）和18楼（0.06）的的数据基本相近。4 m% l- g Z$ r5 x& c. u
& h5 Q9 {. N+ p N因此，拉动飞机的所需的水平力约等于0.02-0.06倍的飞机重量。 9 r1 d# ?6 m) ~/ ~& x4 z3 h2 h0 u
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发表于 2014-7-2 14:25:06
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