Talk-Polywell.org

I have posted a thread on Thrust from Centripetal forces, and another thread on the Space Elevator competition, here viewtopic.php?t=1565 and here viewtopic.php?t=1579 Both are short threads.

The Centripetal Forces device devolved into a Dean Device and fails to lift for a lack of a fulcrum to impart a reactive force. I propose an energy balance evaluation of a device combining the two concepts.

That is, I propose a Space elevator car lifted by a Dean Device, where the fulcrum of the Teeter-totter on the Dean device is attached to the Space Elevator cable using a one-way brake. The anchor point of the fulcrum is allowed to freely rise, but not allowed to slip downward. This way the lift from the centripetal forces will be applied to the elevator car but the reactive forces resulting from stopping the downward momentum of the spinning masses will be transferred to the cable.

Using fully ideal components, I don't see where the energy balances. Obviously, energy includes the potential energy stored (the mass of the elevator car times height in the gravity field) plus any kinetic energy of the elevator car that might be imparted. So when I wrote above, "I propose an energy balance evaluation," I meant, "I propose that you guys do an energy balance evaluation." To me, I see only the proposed benefits of a Dean type of lifting device so the energy required is just that needed to operate the device to overcome real-world losses with nothing extra required to lift the elevator car. If that were true, such a device would greatly simplify the beamed power requirement as well as the climb time limitation.

We have a second place winner. A couple of guys calling themselves "LaserMotive" won the second place prize of $900,000.
http://www.nytimes.com/2009/11/08/scien ... TE&ei=5043

Thomas Nugent and Jordin Kare, the company’s principals, do not believe that a space elevator will be built any time soon, but they say the technology will find other commercial applications like powering small robotic aircraft. “This is a business for us,” Mr. Nugent said. “We’re trying to turn this into a commercial endeavor.”

Mr. Nugent declined to say how much LaserMotive had spent in competing the past three years, but said, “We will win more than we have spent.”

That leaves the $2,000,000 first prize available to be won by using innovative technology. Can we do it at a profit?

I read this on Jerry Pournelle's web site:

A former Peenemunde rocket scientist associate of mine (this was all in the 1950's) said that some charlatan had

built a gadget that sounded a lot like this thing in that it would climb a string and rock like a pendulum, but it was in

fact taking advantage of Newton's 3rd law (for every action there is an equal and opposite reaction), not

overcoming it.

http://jerrypournelle.com/science/dean.html

So it looks like there is hope for a Dean Drive Space Elevator Lifter after all. The Space Elevator Lifter doesn't need to overcome Newton's third law, it is perfectly acceptable if it only provides high acceleration rates and low power consumption. Therefore, the energy balance needs to be worked. I will make a concept drawing and post it. Then there will be something for you guys to look at here.

Aero wrote:I read this on Jerry Pournelle's web site:

A former Peenemunde rocket scientist associate of mine (this was all in the 1950's) said that some charlatan had

built a gadget that sounded a lot like this thing in that it would climb a string and rock like a pendulum, but it was in

fact taking advantage of Newton's 3rd law (for every action there is an equal and opposite reaction), not

overcoming it.

http://jerrypournelle.com/science/dean.html

So it looks like there is hope for a Dean Drive Space Elevator Lifter after all. The Space Elevator Lifter doesn't need to overcome Newton's third law, it is perfectly acceptable if it only provides high acceleration rates and low power consumption. Therefore, the energy balance needs to be worked. I will make a concept drawing and post it. Then there will be something for you guys to look at here.

Best it not be called a Dean mechanism or certain persons will be all over you.

So the concept then is jerking your way into orbit?

So the concept then is jerking your way into orbit?

Hmm. I wonder if it would be a first?

I've ran some numbers and that's what it boils down to in some configurations. I don't see those configurations as being practical. With the elevator coming to a dead stop between rotations of the centripetal force device (wheel), (as it must for the brake to hold), movement is on the order of millimeters per jerk. The faster the wheel spins, the shorter time the lift force is applied so the jerk is stronger, shorter and more frequent. With ideal rigid materials it vibrates its way up the cable, with real world materials there would be a lot of flexing going on. I have a drawing of this configuration but didn't post it since the shortcomings are obvious even to me.

Need an arrangement with shock absorbers to allow the massive elevator car to move uniformly while the centripetal drive device jerks it upward. But more importantly, need a means of harvesting the downward centripetal force (while the brake is locked) and converting this to upward force. I imagine a coil spring motor mechanism. Without using this downward force in some way, I don't see any significant upward speed of the elevator car. Of course I might more easily capture the side to side forces and convert them to upward force. For a force to do work, movement must be allowed ...

But it's all getting complicated, isn't it.

I just drew up another picture. Can anyone analyze this without resorting to conservation of energy as the answer.

http://aeroaero3.bravehost.com/

Actually, you might need to spin it up to get it going, but start-up is a detail.
The question is, "What is the steady state shaft power out?" And how do you calculate it? You'll need to make up your own values for the parameters.

Does anyone have a recommendation of a free image hosting site? Bravenet.com won't allow remote image linking.

Photobucket.com

KitemanSA wrote:Photobucket.com

.
Thanks KitemanSA. I Googled it, read some reviews, then decided to check with my ISP. Yes, my ISP provides a free web page to members and remote linking is permitted. This is my shakedown run to verify that it all works as advertised.

I still have the question of energy balance for the centripetal force wheel, so here are some pictures of what I think are equivalent devices. The first device provides a left and right centripetal force thrust to the crankshaft spinning the flywheel.

The second device provides a left, up, right, and up centripetal force thrust to the crankshaft,

and the third device does away with all the linkages providing the centripetal force thrusts directly to the flywheel. Of course in all cases, the spinning mass and the spinning flywheel must be synchronized.

The remote linking seems to work, so the question is this:
How does one analyze the power out from the flywheel without resorting to the claim that power out equals power in minus losses, that is conservation of energy.
OH, it just dawned on me. In Figure 3 it is clear that when they both spin at the same speed relative to the floor, the mass doesn't move at all, relative to the wheel.
What about Figure 2?