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The Wright brothers’ patent: Plane stabilized in roll by a pendulum. It seems impossible.

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The Wright brothers’ patent: "Plane stabilized in roll by a pendulum" (US Patent no. 1,075,533). It seems impossible.

"The pendulum rocket fallacy is a common fundamental misunderstanding of the mechanics of rocket flight and how rockets remain on a stable trajectory." Robert Goddard fell into this trap as late as March 16, 1926 when he tested a liquid fuel rocket. The Wright brothers filed their US Patent no. 1,075,533 in February 1908,  tested the stabilizer in December 1913 and it worked flawlessly. Orville Wright even got a prize for his achievement (see the book below).

How is it possible? A pendulum with its pivot in an accelerated movement (like inside an airplane) does not tend to align to the vertical and can not be used as a reference like a gyroscope.

Is there another case when somebody succeed in stabilizing a plane in roll using a pendulum?

The 5 Wright brothers' patents:
- The US patent no. 821,393, granted on May 22, 1906, and its foreign versions, claim: (1) the method of wing warping, in particular, and the ailerons (already invented in 1868 by M. P. W. Boulton), in general, for stabilizing an aeroplane type machine in roll, (2) a movable vertical tail aimed at counteracting the adverse yaw generated by twisting the main wings, (3) a flexible front elevator for maintaining the pitch stability of the same machine, (4) various constructive details.
- The French patent no. 384.124, published on March 30, 1908, and its foreign versions, claim two more vertical rudders, placed in front of the main wings, one fixed and the other mobile. They were aimed at better counteracting the adverse yaw.
- The French patent no. 384.125, published on March 30, 1908, and its foreign versions, claim two additional vertical rudders, placed close to the tips of the main wings. Their purpose was also for eliminating the adverse yaw.
-> The US Patent no. 1,075,533, granted on October 14, 1913, and its foreign versions, claim automatic stabilization mechanisms: in roll, driven by a pendulum, and in pitch, governed by wind vanes (two models are proposed). 
- The US patent no. 908,929 - “Mechanism for Flexing the Rudder of a Flying Machine or the Like”, granted on January 5, 1909, and its foreign versions, claim systems aimed at flexing the rudders of an aeroplane type machine for the purpose of modifying their lift.

The-Wright-brothers-patents-and-their-lo

The book contains the patents of the Wright brothers in full and can be downloaded from here: removed by moderator due to copyright restrictions

Edited by Phi for All

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Patents aren’t peer-reviewed science. AFAIK the patent office checks them to see if the idea is novel, not to see if it works.

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2 hours ago, swansont said:

AFAIK the patent office checks them to see if the idea is novel, not to see if it works.

I believe there is only one exception to this. They refuse to patent perpetual motion machines until they can be proven to work, but AFAIK your comment is exactly correct for all other submissions

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8 minutes ago, iNow said:

I believe there is only one exception to this. They refuse to patent perpetual motion machines until they can be proven to work, but AFAIK your comment is exactly correct for all other submissions

My understanding is that the USPTO simply has a blanket ban on patents for perpetual motion machines. They just go straight to the "rejected" pile without any further consideration (and no appeal). (This is effectively the same as "until proven to work" but without the time wasting!)

3 hours ago, simplex said:

How is it possible? A pendulum with its pivot in an accelerated movement (like inside an airplane) does not tend to align to the vertical and can not be used as a reference like a gyroscope.

It might be of limited use when the plane is accelerating, but once the plane has reached a steady velocity I can see that it could be a useful indicate of the angle the plane is flying at. It might need to be damped to avoid being thrown around by every bump.

3 hours ago, simplex said:

The book contains the patents of the Wright brothers in full and can be downloaded from here:

Do you have the author's permission to pst this here?

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1) That document I posted appears to be free. There is no restriction on it. Also, the patents of the two brothers are freely available on the net.

2) I am not talking about the acceleration of the pivot along the longitudinal axis of the plane but about its centripetal acceleration as the plane rotates to the left or to the right. Even if the rotation movement is at a constant speed (which is not the case with inside an airplane) the acceleration of the pivot will not be zero (see the animation below)!

 

PendMovingPivot_127.gif

The random trajectory of a pendulum when its pivot rotates at constant speed about the point (0, 0).

Source: https://www.maplesoft.com/applications/view.aspx?SID=4888&view=html

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4 hours ago, simplex said:

How is it possible? A pendulum with its pivot in an accelerated movement (like inside an airplane) does not tend to align to the vertical and can not be used as a reference like a gyroscope.

I'm not the right kind of Engineer for this-- but it does not seem impossible to me at all.  Consider a weight hanging from a pivot point in the aircraft.  When the aircraft rolls to the left without deviating from its forward path (rotational acceleration only), the weight, responding to gravity, will pivot toward the left of the aircraft.  When the aircraft rolls right, the weight will pivot to the right.  If this weight was connected to some sort of control cable the action of the weight could be harnessed to counteract the roll.  Now, I have not read the book and have no idea if this is what the Wright Brothers did-- but it seems to me the principle might be viable to some extent.

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8 hours ago, simplex said:

1) That document I posted appears to be free.

Unless it specifically says so, you do not have permission to copy it. 

 

8 hours ago, simplex said:

2) I am not talking about the acceleration of the pivot along the longitudinal axis of the plane but about its centripetal acceleration as the plane rotates to the left or to the right.

If the planes turns to left of right then the pendulum will swing the other side at. Which is kind of the point. 

8 hours ago, simplex said:

see the animation below)!

If your plane were moving like that, then I think you have bigger problems than whether a pendulum can show your orientation 

8 hours ago, simplex said:

The random trajectory of a pendulum when its pivot rotates at constant speed about the point (0, 0).

It is hard to see how this is relevant to a plane in controlled flight

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1) The book is free. I found it here: http://wright1903dec17.altervista.org/Wright-patents.htm

2) I have just made an experiment with a simple pendulum built by me. While moving its suspension point to the left or to the right, the trajectory of the bob is always random. There is no relation between the degree of rotation of the pivot and the position of the rod relative to the vertical of the place. In fact, on the gif animation I posted, it is quite visible, immediately after the moment the suspension point starts to move form the point (0, -1) to the right, that the bob travels also to the right. However, after the second pass of the pivot through (0, -1) the bob goes to the left, despite the fact the pivot performs the same movement as immediately after the start. It is a total mess. Such a "stabilizer" can not work. I should have made the experiment by myself before opening this topic not after.

Edited by simplex

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39 minutes ago, simplex said:

1) The book is free.

It is still copyright and you do not have permission to copy it.

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Get a life man. Write to the author and ask him if the book can be freely distributed. You are really annoying. I did not copy the book, I just quoted it.

Edited by simplex

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1 hour ago, simplex said:

Get a life man. Write to the author and ask him if the book can be freely distributed. You are really annoying. I did not copy the book, I just quoted it.

I have a life. Unfortunately, a large part of it is concerned with the protection of intellectual property rights. I will ask a moderator to remove the copy of the book from the first post, now you have provided a link to it.

2 hours ago, simplex said:

2) I have just made an experiment with a simple pendulum built by me. While moving its suspension point to the left or to the right, the trajectory of the bob is always random. There is no relation between the degree of rotation of the pivot and the position of the rod relative to the vertical of the place.

That is why I think a system like this would need to be damped. I think the pendulum could provide a useful indication of flight angle (if that is the intended purpose) but only if not allowed to swing in an uncontrolled way. So more of a plumb line, than a pendulum. I assume the intention is that this is then used to control the attitude of the plane, either by just giving an indication to the pilot or by being directly connected to the control surfaces.

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13 hours ago, simplex said:

 The random trajectory of a pendulum when its pivot rotates at constant speed about the point (0, 0).

Is that the motion the system is trying to stabilize? Is that a motion commonly observed with airplanes?

 

17 hours ago, simplex said:

The Wright brothers’ patent: "Plane stabilized in roll by a pendulum" (US Patent no. 1,075,533). It seems impossible.

"The pendulum rocket fallacy is a common fundamental misunderstanding of the mechanics of rocket flight and how rockets remain on a stable trajectory." Robert Goddard fell into this trap as late as March 16, 1926 when he tested a liquid fuel rocket. The Wright brothers filed their US Patent no. 1,075,533 in February 1908,  tested the stabilizer in December 1913 and it worked flawlessly. Orville Wright even got a prize for his achievement (see the book below).

How is it possible? A pendulum with its pivot in an accelerated movement (like inside an airplane) does not tend to align to the vertical and can not be used as a reference like a gyroscope.

Where does the quote come from? Is there a description/report of the test where the stabilizer "worked flawlessly"?

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35 minutes ago, Strange said:

The quoted sentence seems to e from here: https://en.wikipedia.org/wiki/Pendulum_rocket_fallacy

Although I don't see how that is relevant to the proposed use of an actual pendulum in a plane.

That explains the fallacy, and I agree it doesn't seem to apply, but I'm also interested in how the Wright brothers tested their idea and how it "worked flawlessly" and yet there's no followup on that point. 

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I don't know if we have any pilots involved in this discussion.

When a plane 'rolls', it is referencing a banking maneuver, where it dips the wing on one side while elevating the wing on the opposite side.
If the plane continues in a straight line, while banked, any suspended weight will tilt toward the 'low' side as OldChmE implies.

However, since a plane has more control authority invested in its large wings, a bank is usually initiated to make a turn towards the 'low' side, using wing lift to lift the nose of the plane into the turn ( discussing only naturally stable aircraft at the moment ), and this implies a circular accelerated motion towards the 'low' side. As a result the suspended weight will have some tilt ( depending of acceleration or turn rate ) towards the 'high' side of the bank; a conflicting result from the straight and level case.

I would think this makes any suspended weight useless for the purpose of stabilization.

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When I hear "stabilization" I think of feedback to small perturbations, in order to maintain some steady-state. Not banking or turning, which are not mentioned in the title of the patent mentioned first in the OP: "Plane stabilized in roll by a pendulum" 

Roll is rotation about the front-to-back axis of the plane. One wing goes up, the other down. AFAICT t

he pendulum animation given is not an example of roll.

 

What I think is required is a clear and concise summary of what these efforts were trying to achieve. Otherwise there is the prospect of arguing about something that was not intended by the patent, which is pointless.

22 minutes ago, MigL said:

I don't know if we have any pilots involved in this discussion.

When a plane 'rolls', it is referencing a banking maneuver, where it dips the wing on one side while elevating the wing on the opposite side.
If the plane continues in a straight line, while banked, any suspended weight will tilt toward the 'low' side as OldChmE implies.

And it will take time for a pendulum to swing into position. Further, if you look at the patent in question, it's not just a simple pendulum, and it isn't oriented vertically.

 

starting at line 77:

"under normal conditions the pendulum 87 is at sub-stantially right angles to the aeroplanes and maintains the valve 82 in its closed position"

So what are we to think about an objection based on a claim that the patent is discussing a pendulum aligning to the vertical?

 

 

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Without the book we have no base for any discussion so I propose this topic should be closed. What copyright restrictions? There is no copyright restriction. Fore somebody who reads the first post, there is no way to take a look at the Patent no. 1,075,533 and the comments made there about it and other patents.

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19 minutes ago, simplex said:

Without the book we have no base for any discussion

You provided a link to the book. That is enough.

19 minutes ago, simplex said:

What copyright restrictions? There is no copyright restriction.

Of course there is. Someone wrote a book. They own the copyright. 

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9 minutes ago, simplex said:

Useless discussion that goes to nowhere. I want this topic deleted.

!

Moderator Note

We don't delete topics. And it's only useless if you continue to ignore the questions that have already been posed based on the link to the book. Why aren't those discussable in a meaningful way?

If you're only here to promote the book, then you're not here in good faith, and you're breaking several rules. If you're here to discuss the ideas in the book, then please start with the comments others have already made. 

 

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1 hour ago, simplex said:

Useless discussion that goes to nowhere.

There has been quite a lot of discussion of the pros and cons of the use of a pendulum in a plane.

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6 hours ago, simplex said:

Without the book we have no base for any discussion so I propose this topic should be closed. What copyright restrictions? There is no copyright restriction. Fore somebody who reads the first post, there is no way to take a look at the Patent no. 1,075,533 and the comments made there about it and other patents.

Somehow I got to the patent with the links you provided. That’s how I figured out you’re misrepresenting it.

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You are a total ignorant. You are not even able to write the equation of a simple pendulum with a static pivot. You wrecked the topic I opened. CLOSE IT PLEASE, DELETE IT. I did not know that the level of moderators on this forum is so low from the technical point of view. What is your background. Have you graduated a technical university?

Edited by simplex

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46 minutes ago, simplex said:

You are a total ignorant. You are not even able to write the equation of a simple pendulum with a static pivot. You wrecked the topic I opened. CLOSE IT PLEASE, DELETE IT. I did not know that the level of moderators on this forum is so low from the technical point of view. What is your background. Have you graduated a technical university?

!

Moderator Note

We attack ideas here, not people. You need to stop this now. 

So far it seems like you're just attacking those who disagree with you. And Dr Swanson works about 10 miles away from USPTO HQ. He knows his patents, and his physics. One more chance to discuss this topic civilly, meaningfully, or else it's closed. Your objections are silly. Why can't you answer questions?

 

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