削制飞机螺旋桨

削制飞机螺旋桨 样削制飞机螺旋桨(制作说明) 一、螺旋桨的一些基础概念 当我们把螺旋桨看成是一个一面旋转一面前进的机翼时，就能借助已知的空气动力学常识，直观地理解螺旋桨的基本工作原理。 1(桨距、动力桨距和几何桨距 桨距:从广义而言，可以理解为螺旋桨旋转一周沿桨轴方向所通过的直线距离。习惯上螺旋桨70%半径处的桨距值为“称呼值”，它具有标示意义。 动力桨距(Hg):桨叶旋转一周模型飞机所通过的距离(见图1)。螺旋桨时首先要确定动力桨距值。 几何桨距:(H):桨叶弦线迎角为零时，螺旋桨旋转一周所前进的距离(也见图1)。它体现了桨叶角的实际大小，是“看得见、摸得着”的实际参数。航模图纸上一般都标出几何桨距，是消制螺旋桨的主要依据。 2(动力桨距和几何桨距的关系 由于螺旋桨工作在接近于有利迎角下，与零度迎角之间的角差的存在，因此动力桨距值必然小于几何桨距值。几何桨距和动力桨距的关系是:几何桨距(H)= 1.1 ~ 1.3倍动力桨距(Hg)。也就是说，设计模型飞机时，动力桨距确定后，可以通过上述公式概略估算出螺旋桨的几何桨距。 3(通常使用的螺旋桨是各段几何桨距值相等的所谓等距桨。它的优点是设计、制作比较容易;缺点是工作效率劣于不等距桨。由于不等距桨各段的几何桨距值和桨角均不一样，尽管其效率高，但制作的难度大。故初学者从削等距桨起步较为稳妥。 4(桨叶角(β):桨叶角是指桨叶剖面弦线与旋转平面之间的夹角。 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 5(几何桨距和桨叶角的关系 几何桨距和桨叶角直接关联，是同一个问题的两种达方式。几何桨距强调的是总体，桨叶角强调的是局部。就等距螺旋桨而言，桨叶角随其在螺旋桨半径方向上所处位置的不同而异;随着由桨根到桨尖方向的逐渐位移，桨叶角渐渐有规律地减小。(图2) 二(螺旋桨的外形特征 螺旋桨外形特征的形成，是基本原理、使用要求和材料三个因素相统一的结果。信托这些特征在脑子里建立起螺旋桨的“思维模型”，会使实际操作有的放矢。 1(桨叶的剖面 由于桨叶弦长很小，剖面很薄，航模爱好者以往对螺旋桨剖面形状的研究较少，大多根据粗略感觉和“两个桨叶对称”原则一带而过。但为了追求高效率，有必要对螺旋桨剖面进行探讨。 螺旋桨工作效率最高和一段在60% ~ 80%半径处。这一段一般为桨叶的最宽处，桨叶厚度约为弦长的12%。桨尖的弦长比较小，厚度约为10%。故靠近桨尖部分应注重减小阻力。桨根部分的线速度小，工作效率低，这部分桨叶剖面主要应服从保持强度和刚度的需要。图3为螺旋桨的几个典型剖面。图4为桨叶最宽处我桨尖的剖面(笔者设计;坐标见表1、表2)。其最高点在35%弦长处。从理论上考虑，最高点应在25%左右为佳;而从工艺上看，最高点太靠前可能使桨叶中段的最大垂直厚度超过桨根厚度，形成凸起，使桨的外形不合理。35%是综合权衡的结果。 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 2(桨叶角的变化规律决定了桨叶呈一扭曲的片状:下弧表面大部分为一次曲面;上弧大部分为二次曲面。桨毂上下弧和桨尖端面为平面(图5)。 3(为了结构强度的合理化，桨根处的剖面最厚，随着向桨尖处位移而逐渐减薄。把握住桨根处上弧最高点线和下弧靠近桨根处后缘线的位置和走向(见图5)是关键。上弧最高点线太靠前会使桨根截面积减少，削弱强度;下弧后缘线靠后，不但降低了桨根强度，还使桨根处的桨距不能达到(小于)设计值。这两条线如划得合理，就基本能肖桨进出现“思圆行方”式的纰漏。 三(削制螺旋桨的主要步骤 制作螺旋桨的木材用桦木、榉木、色木或柞木等;其中最常用的是桦木。 1(通过作图法(图6)求出前缘最大高度后加上约2毫米即为桨木厚度。这个螺旋桨的桨木是8×22×200(毫米)桦木。木材的纹理要顺直，把较平整的一面作为下弧，并在平整的工作台上铺一细砂纸进一步磨平作为基准面。 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 2(在钻台上用直径Φ5的钻头在桨木上弧中心点打孔(图7 - 1)。做一划中心线的辅助工具(图8)，把它穿在已穿过桨木中心孔的5mm钻头柄上，紧贴桨木上弧。用大头钉穿过两端的小孔在桨木上扎两个小记号(图7 – 2);再借助记号划出中心线(图7 – 3)。 3(依照正面样板，在桨木上弧画出桨的正面(俯视)投影(图7 – 4)。为了做到螺旋桨完成后两个桨叶长度完全相等，最好在桨在之外另延长5毫米;待桨削好，涂敷涂料前重新用正面样板在下弧划上端面线，用手工锯沿线截断;再仔细把截面磨齐(插图中未画出这一步骤)。 4(把划好线的桨木夹在台钳上，用手工锯沿线的外沿(距离尽量小)概略锯出桨的俯视投影轮廓;再用细木锉和钢锉进一步加工修整;最后用覆上细沙纸的砂纸板打磨到位，桨的正投影即完成(图7 – 5)。应仔细检查、切实做到两个桨叶投影面积完全一致，且所有边缘面和基准面垂直。 5(在下弧划出靠近桨根部分的后缘线;在侧面概略划出前缘线(图7 – 6)。 6(用手工锯在下弧面上锯出开口，用扁铲粗略地铲去就去除的部分;用细木锉修整后，用桨距规对桨叶角进行测量、修正(图9);待接近设计值时，改用钢锉和砂纸板对桨叶角summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 进行细加工，直到符合设计值。桨距规可以参照图10用有机玻璃自制。图7 – 7为桨叶下弧的保留部分和去除部分。 7(画出上弧靠近桨根处的最高点线。 8(切削上弧:先用刻刀切削;最后的细加工过程与加工下弧的办法相同。(图7 – 7) 随着加工进程形成新外形的同时，木材的内应力会随之发生一些变化，应注意检查和细修桨叶角。 最后修出前缘外形。桨根处的前缘比较肥厚，具体处理办法是把这一处的下弧向上修圆滑，以减少阻力(参考图3、图5)。桨的后缘不能尖利，应保留0.2毫米厚度，以防拨螺旋桨启动发动机时划伤手指。 上述8个步骤仅是按部就班的过程，还须对具体环节细化思考，周到处理。例如，有些加工程序可在两个桨叶上交替同步进行，既可防备万一失误而使前期更多工作量付之东流，也可减少已完成部分出现一些后期变化等。 削好螺旋桨的关键在细节。“细节决定成败”;“细节之处见真章”。这两句话可作为完成上述8个步骤后的总结。 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 四(检查静平衡 通常，航空模型螺旋桨的工作转速范围在5000~20000转/分，对动平衡要求高。而静平衡是动平衡的基础条件。假如螺旋桨的两个桨叶从材料的质量到桨叶角、外形完全相同，实现动力平衡应顺理成章。问题是，这一基础条件并非轻易能具备。我们能做到的是尽量使两个桨叶任意一处的剖面相互对称;尽力实现静平衡。 螺旋桨静平衡程度如何，可通过自制的平衡检查架检查(图11)。理想的静平衡状态是:螺旋桨无论处于价格体系角度均能自行静止;如果某一桨叶静止时的位置总是“下沉”，即应找出这个桨叶与另一桨叶的差异，并且进行修正、再试，直到合格。 五(涂敷涂料 涂敷涂料前，应分别在两个桨叶的适当位置，用黑色签字笔清晰地写上桨的参数(D=200、H=120)作为备忘。日后螺旋桨损坏时，可根据残骸上留下的参数制作。 涂敷涂料应选择在晴朗干燥的天气下进行。 先用软布擦去螺旋桨表面残留的木屑、尘埃等;再刷上几遍透布油(不要把螺旋桨孔和桨尖端面遗漏)。透布油完全干燥后，把少许“502”胶液，用事准备好的白色绸布薄而均匀地迅速涂敷在螺旋桨表面上。为便于手持，先涂敷大半部分，干后再涂敷其余部分。“502”胶属速干型粘合剂，这一工序应一次性快速完成，不能反复涂抹，以免把表面拉毛而使之推动光泽。 削好的螺旋桨要在试车台上作试运转。当发动机以各种转速运转时，从侧面看上去，在桨尖处应始终呈现出一个清晰的“圆环”。如出现“双环”现象或颤动，表明存在缺陷。有缺陷的螺旋桨应立即检查修正，禁止勉强使用。 削制几根同样参数的螺旋桨，就做到桨叶角、外形和重量一致，使它们有互换性。 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 至此，我们就可以把自己精工细作、如同工艺品般的螺旋桨安装在心爱的模型上了。新 螺旋桨既能为模型增力，又可为模型增色，很成功(图12)～ 表1 LXJ-10%(螺旋桨桨尖剖面) X 0 0.2 0.4 0.6 0.8 1.25 2.5 5 7.5 10 15 Y上 1.89 2.73 3.05 3.25 3.40 3.72 4.49 5.64 6.49 7.19 8.31 Y下 1.89 1.04 0.73 0.51 0.34 0.11 0 0 0 0 0 X 20 25 30 35 40 50 60 70 80 90 100 Y上 9.10 9.61 9.90 10.00 9.86 8.69 7.28 5.89 4.46 3.00 1.50 Y下 0 0 0 0 0 0 0 0 0 0 0 表2 LXJ-12%(螺旋桨中段剖面) X 0 0.2 0.4 0.6 0.8 1.25 2.5 5 7.5 10 15 Y上 2.00 2.87 3.17 3.43 3.60 3.90 4.73 6.23 7.47 8.49 10.02 Y下 2.00 1.13 0.80 0.57 0.40 0.15 0 0 0 0 0 X 20 25 30 35 40 50 60 70 80 90 100 Y上 11.02 11.60 11.90 12.00 11.90 10.80 9.07 7.24 5.37 3.45 1.50 Y下 0 0 0 0 0 0 0 0 0 0 0 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into