线控飞机平尾与垂尾的联动机构设计。。顺带请高手翻译

生活是一盘菜

前言：

长久一来，线操纵垂尾一直是固定的。但在不同飞行姿态下，要求垂尾的尾力臂控制力度不同。比如在俯仰姿态下，要求垂尾有更大的偏转角度来保证机身姿态与平飞一样，而且有更大的向外张力。不同姿态下垂尾角度变化一直是缺乏有效控制手段。

国内有人设计了三线控制方式。第三根线主要就是控制垂尾偏转角度。但手上动作变化大，导致垂尾偏转角度不一致。而且增加一根操纵钢丝势必增加很大飞行阻力。

下面介绍的联动机构实际上是垂尾与平尾随动。这样便于调整，对飞机影响不大。原文对垂尾多种不同的初始设置进行了研究，很有借鉴意义。附原文（请高手翻译）

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Al Rabe's Movable Rudder setup
A description by Al Rabe of how he set up the Moveable Rudder on his latest masterpiece

There is still a great deal of confusion about the use and adjustment of the movable rudder (actually, I never called it a "Rabe Rudder"). I thought the article in Stunt News Nov/Dec 2001 issue covered the subject well. It answered all the theoretical questions about how it works and described how to install and adjust one.
Questions still arise. Without going into great detail of explanation about the use of the moving rudder, I thought I'd simply show some of my trim reasoning.

Photo 1.
This simply shows a typical installation of the movable rudder on Snaggletooth. The point here is that the elevator end of the pushrod is below and about 45 degrees behind the elevator hinge line. It is simply a cut off and drilled plastic horn.


Photo 2.
This photo shows several elevator end horns and their pushrods. The middle one is Sanggletooth's first

Photo 3.
This photo shows a template custom made for Snaggletooth, for visualizing and adjusting its rudder movement. There was a similar template published on the Mustunt plans and a photo of a template in the Stunt News article. The photos of my Snaggletooth template here demonstrate my belief in the use of a similar template for systematic trimming adjustments. Without systematic adjustments, satisfactory operation of the rudder is a matter of luck. If the movable rudder doesn't meet expectations, one can always claim the thing obviously doesn't work

Photo 4.
This photo shows my best guess at a good setting and the adjustments I used for the first flight. "0" on the template is zero offset of the rudder when the elevators are at neutral. Each mark is 1/8", but, to simplify explanation, I'll call each mark a "unit". In this case I set the rudder to be 1 1/2 unit offset with the elevators at neutral. Why? I simply like a bit of rudder offset.

Photo 5.
This photo shows the rudder, on full "up", has moved to minus 1/2 unit, inboard, or left two units total from the neutral elevator position.

Photo 6.
This photo shows the rudder position with the elevators full "down". In this photo the rudder is at 5 1/2 units. It has moved outboard, or right, four units from its elevator neutral position. That is a ratio of two to one for outboard versus inboard movement from elevator neutral. I typically use a ratio of three to one. The ratio is dependent on the location of the horn "pickup" at the elevator end of the pushrod. In any case, it is much better to use too little movement as opposed to too much. In the case of Snaggletooth, There is more rudder movement than I'd recommend. The reason being that I was running a very large 14 1/2" prop and anticipated much more than normal gyroscopic precession. This would require more correcting rudder movement than would be typical. A typical rudder initial setting for most stunt ships would be to move one unit (1/8") inboard of elevator neutral position and three units outboard of the elevator neutral position for a typical three to one ratio of relatively small movements.

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On its first flights, Snaggletooth had a bit of wobble in outside corners with these settings, otherwise it seemed OK. I figured it needed more right rudder on "down". I moved the pushrod in one hole on the rudder horn to make the rudder more sensitive. It would move more on both "up" and "down". The next flights proved the outside corners smooth now, with the rudder on "down" at eight units. I was also beginning to pick up a bit of slack on the first loop of the cloverleaf, an inside loop. I tried another hole inboard on the rudder horn and found no improvement in the outsides and a definite loss of tension in that cloverleaf first loop. The use of rudder movement inboard of rudder neutral may be appropriate and is theoretically correct to compensate for the outward yaw on inside, nose up, pitching maneuvers. It just happens that Snaggletooth doesn't like it. Theoretical correctness or no, practical trimming requires that observed deficiencies be addressed. One possible solution to the problem would be to simply return the pushrod to the outside hole on the rudder horn and crank in more offset which would give less inboard rudder position on "up" and more outboard rudder position on "down". This would have certainly given an improvement in both inside and outside corners, but would result in more offset with elevator neutral than I wanted. Another possibility would be to change the ratio of inboard movement to outboard movement so that the rudder would move less toward the inside and more toward the outside. This is accomplished by moving the elevator end of the rudder pushrod farther from the hinge line. If this is done to an extreme, the geometry might even cause a bit of outboard movement on "up" in addition to more outboard, or right, rudder on "down". I don't recommend this degree of asymmetry and have never had to use it in the past to obtain optimum trim. Snaggletooth, however, doesn't like any inboard movement of the rudder from the neutral rudder position on "up". It tends to weaken that first cloverleaf loop. Everywhere else is OK and I can "whip" that entry, but it is better to trim rather than to rely on "whipping".


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Photo 7.
this shows a rather extreme position of the elevator end of the rudder pushrod. The pickup has been mover about 1/4" aft, increasing the angle downward and back from the elevator hinge line to about 60 degrees. I don't recommend using this much asymmetry. It has never been necessary in the past. AND, I haven't flown it yet with this setting, which may prove to have too much asymmetry. I'll fly it and make further adjustments as necessary. I think that starting off with this much asymmetry a poor choice, and, you'll notice, I didn't.

Photo 8.
This photo shows the rudder offset with the elevators neutral is still about 1 1/2 unit. this is the same as the initial installation.

Photo 9.
Check this out. the rudder started the move slightly inboard as the elevators moved "up" and then moved slightly, about 1/2 unit out. This gives little or no position change of the rudder on "up".

Photo 10.
This final photo shows the rudder moving to about eight units when the elevators are "down". From trimming trials so far, this should be approximately the desired position of the rudder on "down". The increase in asymmetry has had this net effect. The overall rudder offset is the same as I started with. The right rudder position on full "down" is about where I liked it when I tried more sensitivity. The left rudder movement on "up" has effectively been eliminated. This combination should give me that smooth, wobble free, and solid outsides, and elimination of any possible harm to the cloverleaf first loop from inboard movement of the rudder.

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It should be noted that there are three separate adjustments possible with this simple device. Overall rudder offset, rudder movement inboard on "up", and rudder movement outboard on "down" are individually adjustable without interfering with preferred adjustments of the other two.,br. In the example above, I managed to reduce Inboard movement and increase outboard movement without changing the base rudder offset. Optimum adjustment of the movable rudder requires a thoughtful understanding of its capability and a template. Movable rudders added to airplanes without adjustment aren't likely to perform well.

........................................................................................需待“总结”。。。。。。。。。。。。。。。。。

[ 本帖最后由 生活是一盘菜 于 2010-6-8 23:00 编辑 ]

生活是一盘菜

In conclusion:
Rudder offset is simply adjusted by the length of the pushrod. With all of the other possible adjustments this is just too simple. Base ruder offset should be whatever you would use if you built the airplane without an adjustable rudder.
Rudder sensitivity, or total movement from one extreme to the other, is controlled by the holes on the rudder horn and, to a degree, by the "pickup" hole on the elevator horn. I try to keep the elevator "pickup" hole no farther from the bottom of the elevator than shown in the photos above and make sensitivity adjustments with the rudder horn. If the outside hole on the rudder horn is still too sensitive, make a new elevator horn with the "pickup" closer to the elevator surface.
Rudder movement asymmetry is controlled by the fore and aft location of the "pickup" hole on the elevator horn. If the "pickup" is directly under the hinge line, the rudder will move equal amounts left and right from neutral offset. This is the theoretically correct location. With sensitivity adjustments, the rudder can be adjusted to remove all of the prop gyroscopic precession from the propeller which precesses the same on both inside and outside maneuvers, but in opposite directions. This was the original intent, and the way the first movable rudders were installed. In practice, it turned out that it was better to overcompensate for the inward yaw on outsides, to add a bit of outward yaw to improve line tension. In practice, it also became apparent that it was best not to remove all of the naturally occurring outward yaw from inside corners. By moving the "pickup" back from the hinge line, I was able to accommodate both of these actions by using more right rudder movement on outsides and less left rudder movement on insides. For most airplanes, this would be about 45 degrees behind the hinge line. I wouldn't use more asymmetry until I was very sure it is necessary. Remember, more rudder offset is another way to get more apparent asymmetry without changing the "pickup".
Now you know everything about how movable rudders work. The rest you learn by observing how the airplane flies in various maneuvers. With practice, you will get the hang of actually changing smoothness and line tension in various maneuvers and getting the best balance throughout the pattern. Trim technique was discussed in the Stunt News article. It might seem desirable to make the airplane yaw out strongly in all maneuvers but, again, that doesn't work very well. Excessive rudder induced yaw will give you more drag, and the drag can kill you in the wind. A balanced and moderate approach to trimming works best. Shoot for enough trim without overdoing it. The airplane should appear smooth and wobble free in corners and retain necessary minimum;m drag penetration in the verticals. Too much asymmetry is just as bad as too much movement. A light touch works best.

生活是一盘菜

请高手翻译----------------------
有一点没看懂，
比如过顶和垂直爬升类直线动作。当进入动作时是先做剧烈的直角动作，这时候平尾偏转角较大，随动机构控制垂尾产生较大偏角。整个设计产生效果。
但动作过后，舵面回中，保持直线飞行姿态。这时候平尾和垂尾保持平直，随动机构没发挥作用。但这时其实是最需要拉线张立的。
初步估计，线控飞机原有的外拉力设计还是得保留，如发动机外拉角。

[ 本帖最后由 生活是一盘菜 于 2010-6-11 09:35 编辑 ]

the3rd-eye

高手都不来这个版块？:em22:

以前曾见过有第三线控制发动机的，但用三线控制方向舵的很罕见，至于方向随动更是第一次见，。
不懂，帮顶！

shark1010

后续总结
总之：
鲁德尔抵消只是由推杆长度调整。 与其他所有可能的调整，这是太简单。 基地粗鲁抵消应该不管你，如果你会使用内置的可调无舵的飞机。
鲁德尔敏感性，或从一个极端总运动，另一方面是受舵角上的漏洞，并在一定程度上，由“皮卡”洞角上了电梯。 我尽量保持电梯“皮卡”孔从比上面的照片所示，并与舵角灵敏度调整电梯底部没有更远。 如果在外面的舵角孔仍然过于敏感的，请与“皮卡”新电梯角接近电梯表面。
鲁德尔运动不对称是受脱颖而出和“皮卡”在电梯喇叭孔船尾的位置。 如果“皮卡”是直属铰线，舵会提出等量遗留中立偏移和权利。 这是理论上的正确位置。 随着灵敏度的调整，可以调整舵删除的道具从螺旋桨的进动的内外演习同样陀螺进动，而是在相反的方向。 这是原来的意图，并首次安装了移动方向舵的方法。 在实践中，原来这是更好地为来弥补对内外引起向内偏转，增加了外向偏航位来改善生产线的紧张局势。 在实践中，它也变得明显，这是最好不要去消除自然产生的从内向外偏航所有角落。 通过移动“皮卡”回从铰线，我能容纳和减少使用内外引起内脏舵运动留下更多的右舵运动这些行动都。 对于大多数飞机，这将是大约45度线背后的铰链。 我不会用更多的不对称，直到我很相信这是必要的。 请记住，更舵抵消另一种方式是让没有改变“皮卡”更明显不对称。
现在你知道一切关于如何移动方向舵工作。 其余的你怎样通过观察演习的飞机在各种飞行学习。 通过练习，你将得到挂起实际变化平稳，线各演习越来越紧张，整个模式的最佳平衡。 修剪技术，讨论了特技新闻文章。 它似乎可取，使飞机偏航出强烈的所有动作，但再次，这并不能很好地工作。 过度舵诱导偏航会给你更多的阻力与阻力可以杀死你在风中。 一个平衡的和温和的方式修剪效果最好。 拍够没有过份的装饰。 飞机顺利，应该会出现在角落里自由摆动并保留必要的最低限度;米的垂直拖动渗透。 太多的不对称是一样糟糕太多运动。 阿轻触效果最好。

飞得高1点

:em23: :em23: :em23:

fq2eye

路过