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A Solar sail in the form of a propeller spun by radiation pressure from the Sun.


Maximillian

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There is a patent I filed last year, It implements solar sails.

To ensure that we keep close to the sun and get most of its radiation pressure, we will use what I call a solar propeller but the name solar mill makes more sense.So lets call it a solar mill. This is a solar sail that instead of being pushed away by the sun's radiation pressure it actually keeps spinning about its axis.

We all agree that we cannot keep on increasing the spin indefinitely because the solar sails will break apart at a certain centrifugal force. To prevent damage to our payload we shall keep it stationary using a gyroscope at the center of the system. A magnetic bearing can be used to reduce friction between the spinning ends and non spinning center. After reaching the desired linear velocity, the mass attachments at the arms will then be ejected periodically in a specified direction to slowly build velocity of the payload. To slow down at the destination the remaining attachments are ejected in the opposite direction.

Suppose you have a solar sail of a circumference of 10km and a mass of one tonne.
Lets assume its material can hold centripetal force at 100rev per second. We shall be having a linear velocity of 1000kms-1. This velocity by such a mass can never be attained using conventional rocket propulsion but thanks to the Sun its no problem. It will take about 3 months to attain this linear velocity if placed at the orbit of mercury.
Is my patent valuable?

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...the mass attachments at the arms will then be ejected periodically in a specified direction to slowly build velocity of the payload. To slow down at the destination the remaining attachments are ejected in the opposite direction...

 

 

Can you explain that, please ?

The solar windmill spin will run an electric generator ? To propel the craft how ? Or the windmill spin is supposed to push the 'air' in deep space for propulsion ?

And what will hold the spacecraft steady instead of following the spin?

 

What would a patent protect ?

Edited by Externet
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How would you keep the center from spinning with the rest. There isn't sufficient friction in space to prevent the center from spinning with the arms.

 

(Just noted Externet asked the same question)

Edited by Mordred
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... This is a solar sail that instead of being pushed away by the sun's radiation pressure it actually keeps spinning about its axis.

...

What's keeping the thing in place? Why doesn't it all just get pushed away?

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And what will hold the spacecraft steady instead of following the spin?

How would you keep the center from spinning with the rest. There isn't sufficient friction in space to prevent the center from spinning with the arms.

Not endorsing the idea - but two counter-rotating mills would sort that problem pretty simply. there would be no net gain in angular momentum and thus the space-craft would/must stay stationary

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However I cannot see how the craft would remain steady in space - linear momentum must be conserved. And I do not understand how this could possibly create a usable motion that is preferable to a simple solar sail. You could place one in orbit around sun to harvest a tiny amount of energy - but a simple photovoltaic would surely be better

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After reaching the desired linear velocity, the mass attachments at the arms will then be ejected periodically in a specified direction to slowly build velocity of the payload.

 

 

How do you do this without unbalancing the system?

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Is my patent valuable?

It's doubtful anyone will use this in the patents life time, so for money making purposes, no.

 

But like all ideas it has value. It seems reasonably practical to me to, I don't see the relevance of the objections raised here. (Not that that means they might not be valid.

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Not endorsing the idea - but two counter-rotating mills would sort that problem pretty simply. there would be no net gain in angular momentum and thus the space-craft would/must stay stationary

True I initially read his post as a single mill. Though I also don't see any gain compared to a simple solar sail

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True I initially read his post as a single mill. Though I also don't see any gain compared to a simple solar sail

I think the main difference is that letting go of the weights allows for rapid course changes. While you could change course by angling a traditional sail , this could only be done effectively within the solar system and take time.

 

Not endorsing the idea - but two counter-rotating mills would sort that problem pretty simply. there would be no net gain in angular momentum and thus the space-craft would/must stay stationary

Why doesn't the magnetic bearing he mentioned prevent the craft from spinning? Why does it matter if the craft spins too, in fact wouldn't some kind of centrifugal artificial gravity be a good thing?

 

Why not put a sail as well as a rotor?

Kind of offtopic: could you make a solar sail from solar panels, or is a mirror most efficient. Is the only loss in efficiency equal to energy gained in electricity, sinice a mirror could be behind the panels?

 

Seems he's a few decades late http://wiki.solarsails.info/index.php/Heliogyro

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if the craft is spinning with the mill you would get no gain from the mill, you may as well just have a sail. Though it doesnt sound like hes using the sail to get thrust but rather to maintain orbit to generate power?

 


To ensure that we keep close to the sun and get most of its radiation pressure,

 

 

The OP needs to better explain the design and its purpose, we are guessing too much due to the brief nature of the post

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if the craft is spinning with the mill you would get no gain from the mill, you may as well just have a sail. Though it doesnt sound like hes using the sail to get thrust but rather to maintain orbit to generate power?

 

 

 

The OP needs to better explain the design and its purpose, we are guessing too much due to the brief nature of the post

Surely you get linear momentum as well as angular.

 

I agree, the OP needs a better explanation, but it seems some of the posters also need better reading comprehension and also fail where the OP does.

 

Anyway answered my question about a solar panel/sail hybrid. http://wiki.solarsails.info/index.php/IKAROS

 

 

Here's how angular momentum is used for existing sail designs. http://wiki.solarsails.info/index.php/Category:Spin_Stabilized

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oh I agree, but hes asking if the design has value without a decent description of the design.

 

lets take for instance the last link you provided. if you want a propeller design to accomplish tension on the sails you wouldnt need a gyroscope. You could just use a pinwheel design on the sails and let the craft spin.

 

Now this line in the OP hints at using a gyroscope to stabilize the craft. However he never specified the type of gyroscope if he uses a mechanical gyroscope this will induce spin.

 

"To prevent damage to our payload we shall keep it stationary using a gyroscope at the center of the system."

 

However a gyroscope isn't commonly used as a stabilizer, its used to sense the orientation of the craft then send that info to the stabilizer. That led me to question what his stabilizer is?

 

one might niavely think 2 opposing direction propellers would stabilize a craft, but once you look into keeping the momentum gain on each perfectly balanced this becomes problematic.

 

lets take for example two propellers on the same shaft. Both with friction reduction bearings of some form. (key note reduction isnt the same as total) not to mention keeping the coefficient of friction perfectly balanced.

 

" A magnetic bearing can be used to reduce friction between the spinning ends and non spinning center"

 

the lead propeller will induce current patterns onto the second propellor the net result is that they will not spin at the same rate. Add this and the problem of keeping the two bearings to shaft coefiicient of friction perfectly balanced equates a problematic design.

 

Surprising enough this doesnt change even on a multishaft design.

 

So how can we determine the value of his design without the key details explained in a more complete answer

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Oh it's got no patent value, which I think it what he was hinting at. There's no way he'll make any money off it before the patent expires.

I'm not even sure it was legal to issue the patent.

 

 

I'm not saying that. I'm saying we can't determine that without the proper details on the design, you can't patent an idea only a design. Also the patent office doesnt care if the design works or not.

Edited by Mordred
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...Now this line in the OP hints at using a gyroscope to stabilize the craft. However he never specified the type of gyroscope if he uses a mechanical gyroscope this will induce spin.

 

"To prevent damage to our payload we shall keep it stationary using a gyroscope at the center of the system."

 

However a gyroscope isn't commonly used as a stabilizer, its used to sense the orientation of the craft then send that info to the stabilizer. That led me to question what his stabilizer is?...

Gyros are often used to stabilize boats. Seakeeper - Gyro Stabilizers for Stabilization of Naval Vessels

...Seakeeper gyroscopic stabilizers are the most effective zero-speed anti-rolling devices ever made. Whether at anchor or underway, Seakeeper gyros provide the enhanced performance, comfort, and safety expected by a diversity of boaters around the world. The beauty of Seakeeper's technology is that you can feel it. ...

For a space application, see Control moment gyroscopes as used on the ISS.

A control momentum gyroscope (CMG) is an attitude control device generally used in spacecraft attitude control systems. A CMG consists of a spinning rotor and one or more motorized gimbals that tilt the rotors angular momentum. As the rotor tilts, the changing angular momentum causes a gyroscopic torque that rotates the spacecraft. ...

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Yeah I was aware of those but without knowing the style being used in the design itself.?

 

 

I think ppl are missing a key detail. Nothing in the idea presented above is unique. There has probably been thousands of similar designs. On another forum I visit (engineering forum) I've read several hundred similar proposals over the past 10 years.

 

So what makes the OP's design any better than any other similar design?

 

How well has the designed been engineered? To what level?

 

How cost effective is the design?

 

The OP isn't asking How to design the craft,he's already designed it. he's asking if his design has value

Edited by Mordred
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Yeah I was aware of those but without knowing the style being used in the design itself.?

I was responding to your comment that they aren't common and the implication such use wasn't viable.

 

I think ppl are missing a key detail. Nothing in the idea presented above is unique. There has probably been thousands of similar designs. On another forum I visit (engineering forum) I've read several hundred similar proposals over the past 10 years.

So what makes the OP's design any better than any other similar design?

 

How well has the designed been engineered? To what level?

 

How cost effective is the design?

 

The OP isn't asking How to design the craft, he's already designed it. he's asking if his design has value

Discussion ensues. :)
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yeah I understand Acme, I should have made this portion clearer. " However he never specified the type of gyroscope if he uses a mechanical gyroscope this will induce spin"

 

just a side note The OP could also intentionally vary the friction of duo propelles using the right components. However I have no idea if thats part of his design

Edited by Mordred
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Yeah I was aware of those but without knowing the style being used in the design itself.?

 

 

I think ppl are missing a key detail. Nothing in the idea presented above is unique. There has probably been thousands of similar designs. On another forum I visit (engineering forum) I've read several hundred similar proposals over the past 10 years.

 

So what makes the OP's design any better than any other similar design?

 

How well has the designed been engineered? To what level?

 

How cost effective is the design?

 

The OP isn't asking How to design the craft,he's already designed it. he's asking if his design has value

 

 

 

I'm not saying that. I'm saying we can't determine that without the proper details on the design, you can't patent an idea only a design. Also the patent office doesnt care if the design works or not.

It seems like the OP's post was exactly as his patent stated.

Actually at this point, because I'm somewhat of a "profiler", I would say that the OP never filed any patent at all. He actually just came up with the idea recently and thought he'd run it by people on science forums to see if they could give him any prompts on improving it, perhaps giving him a design he could patent.

 

The reason he says he did patent it and a year ago, is so that people don't "steal" his idea, and the year ago bit makes it harder to search.

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Might very well be but without detail you can't compare it to similar designs.

 

I do question the patent itself as anyone filing a patent should check the market value prior to paying the patent fees

Edited by Mordred
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Let me try to give more detail as much as I can.

 

The gyroscope will consist of a fly wheel rotating about a shaft placed perpendicularly to the the spin center attached to the payload.

The payload is placed stationary at the center to prevent its avionics from getting damaged due to high accelerations.

 

The main reason am proposing this is we want to store enough angular momentum in the system so that we can transform it to linear momentum by ejecting the reaction mass to move the payload faster than currently possible. This is not possible with current solar sail designs because you always get pushed away before you get enough momentum.

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I'm not even sure it was legal to issue the patent.

 

I don't see why not. Heddy Lamarr (the Hollywood actress) got a patent for spread spectrum radio transmission decades before it became practical (and now ubiquitous).

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