You aren't even extended in that pic. Last time I went out with my best friend the wind gusted and the thing shot forward and tried to scoot out from under me, we were fully extended. I about fell back into my buddy. Damn that was fun!

Hot damn. I own page 2. I think this might be the first time in 3000 posts...

[This message has been edited by Taijiguy (edited 12-06-2005).]

This is a 16 ft. I also had a 14 turbo, which is a 14ft with a jib. Even more fun since I couild right it by myself.
owned three of the 16s at various times. Never lost money on one. Ever time I sold one I,d see one sail and have to get another. Big fun.

quote Originally posted by Wolfhound: This is a 16 ft. I also had a 14 turbo, which is a 14ft with a jib. Even more fun since I couild right it by myself. owned three of the 16s at various times. Never lost money on one. Ever time I sold one I,d see one sail and have to get another. Big fun.

Off Topic: Yay another sailor! Ahh yes, but how much can you drink!?
I sail on four boats but owns none of them. J24, Cal 39, Tayana 55, and a Farr 395.

quote Originally posted by Jake_Dragon: If you have a solar powered flash light and shine it on its solar collector would it charge itself?

Yes but the losses inherant in the system due to the inefficiencies of both the bulb converting electricery to light and the solar cell converting photons to electricery would cause it to run down eventually, it'd just take a little longer thats all.

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Dave E

www.ltlfrari.com

Will the car move?

Ok, I thought of this problem last night in bed, and it kept me awake for quite some time!

Let's get back to the original "vehicle on a conveyor belt" problem. This time, we put a car on the belt.

First a few definitions:

Ground: The ground the conveyor belt is resting on
Belt Speed: The speed of the belt in relation to the Ground
Car's Ground Speed: The speed of the Car in relation to the Ground (not the Belt)

The car is placed on the belt. The belt tracks the car's ground speed and tunes it's speed to be exactly the same but in opposite direction. A guy gets in the car, starts it and starts driving. What will happen with the car?

The thing that kept me awake is this: Suppose the car starts moving at a ground speed of 10mph. That means the belt will start moving with 10mph in the opposite direction, causing the car's ground speed to become zero, causing the belt to stop, causing the car to move forward again, causing the belt... You get the picture.

The problem is that you would expect the car to have a ground speed of zero, since it's always counteracted by the belt. But that's impossible, since if the car would have a ground speed of zero, the belt would not be moving.

Hey cliff i think the car will eventually drive off the end of the converyor. Ok here's why. The car begins to accelorate, the speed tracking device senses the cars groundspeed and starts the conveyor in the opposite direction. As the converyor begins to slow the car it tunes itself (slows down) and the car begins to move forward again (in relationship to the ground) . It would seem to hunt for a happy medium, but since electronics are not instant there will be a lag time. This lag will allow the car to get a headstart on the conveyor system during each on of these speed-up slow down cycles. This will allow the car to travel forward. I think ?

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

It's the same thing as an IAC on a Fiero.
It will hunt back and forth until it finds a happy medium. The car will move forward and backward and the belt speeds up and slows down until they equalize.

The car would gain until it went off the end of the belt
Since the mechanism to move the belt is ground speed rather than wheel speed.

It would half the normal forward travel of the car with one revolution of the tire.

[This message has been edited by Wolfhound (edited 12-06-2005).]

IF the belt speed could change instantly with the change in wheel speed the car would not move.

Good Luck!

Wait a minute, it was ground speed not wheel speed. DOH!
I think this is one of those divide by zero things.

[This message has been edited by Tugboat (edited 12-06-2005).]

If you use a cable attached to the rear of the car to pull the conveyor to the rear by a simple pully the car will drive off the conveyor at half wheel speed.

quote Originally posted by Tugboat: Like I said, going crosswind it works.... Good Luck!

crosswind is gearing.forward speed against angle of source direction.

any energy source can be used 100 percent minus the weight and resistence of the movable mass.

You can't sail downwind faster than the wind. If you did your apparent wind would be negative.

Where crosswind as the boat gains speed the apparent wind rotates toward the front off the boat and increases.

To get back to the original question.....

Perhaps the car will move, but not for long I don't think. The biggest problem and damage cause to windmills is excessive wind, More on this later.
To get any apprecialble hp from the wind, it will take a very large turbine or sail type wind catcher. In a water pumping windmill, like an aeromotor type, the windmill diameter is anywhere from 4' to 20' wide. (20' wide being an exception and I don't think these are very common anymore.) The gearing is nothing more than a geared speed reducer and crankshaft to convert rotary morion to reciprocating motion. If memory serves me, the output after figuring effeciency is about 1-3 hp--and that's output after the gearing. I'll post more tonite after work, and may go by Aeromotor here in San Angelo for some pictures or brochures, but I also think back on the early wind mills that were used to turn very large grist stones for grinding grain.

I once rented an old farmhouse that had an Aeromotor from San Angelo.

I'm going to say NO. What you gain in RPMs by gearing you are going lose in torque. Like a step-up or step-down transformer, you give up one aspect of power for another(volts vs current). And you'll never get enough to overcome inertia, no matter how good the aerodynamics are.

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John DuRette
Custom 85 SE/87 Coupe
"Kinda makes you nostalgic for a Members Only jacket"

On the propeller question:

I think there are too many unknown variables, like:
- wind speed
- propeller size and angle of blades, hence force generated by the propeller
- force required to move the car forward
- drag coefficient of the car

[This message has been edited by Voytek (edited 12-07-2005).]

Here is another flying type puzzle
You are driving your car down a highway ( at normal highway speeds and not on a convayor) with the windows open . A bee is flying across the road and flys into your open window. Is the bee able to fly right through your car and out the other window or does it get splattered against the rear window?

[This message has been edited by Phil (edited 12-07-2005).]

Phil the photo is flying a hull. This is on Lake Martin in Alabama.

The fastest point of sail on a hobie is a beam reach. Note that there are no white caps that start at 13 Knots of wind.
If you can fly one hull with the upper hull close to the water your hull resistence is cut in half and the side of the assimetrical hll acts as a better keel. If the hull gets higher the sail area exposed to the wind diminishes and the trampoline trys to over turn the boat since it becomes a sail.
As you accelerate you tighten sail and keep the jib slot clean and the boat balanced.

In high wind all this is true, but if the balance fails and the center of moment moves forward and the lower hull in the water dives and trips on the water, it,s much like a motorcycle wreck.

Hobies have been clocked at 26 knots, on the water thats fast. It can happen so fast hat you never see it happening.
You're just in the water and the boat is up side down.

Running on the edge is big fun.

A displacement hull boat is what you are thinking of and fits your definition.

[This message has been edited by Wolfhound (edited 12-07-2005).]

Pitch poleing is flipping the boat arse over teakettle by digging the bow into the water. Just a matter of terms

Right , A Hobie just doesn't need the wave.

quote Originally posted by ryan.hess: Oh oh! I have a question! This one has been known to stump even the best of scientists..... I have placed a living cat into a steel chamber, along with a device containing a vial of hydrocyanic acid. There is, in the chamber, a very small amount of a radioactive substance. If even a single atom of the substance decays during the test period, a relay mechanism will trip a hammer, which will, in turn, break the vial and kill the cat. The observer (me) cannot know whether or not an atom of the substance has decayed, and consequently, cannot know whether the vial has been broken, the hydrocyanic acid released, and the cat killed. The question is - what should I put in my coffee?

A small quantity of Schrödinger, just keep an eye on it.

The car cannot move. The trick here is that the propellar is placed on top of the car. Now you guys talked about drag but I don't think that can describe the simple fact of the friction created from the tires to the ground. Strapping a propellar on a car would just increase the coefficient of friction. As always with any type of perpetual motion thing scaling is a problem. A propellar will never be able to geneterate enough power to move itself let alone a car and itself. If you say increase the wind power then that just increases the areodynamic drag on the car combined with the friction wouldn't move it. If anything when all is said and done it may just move backwards. The only way a propellar could move a car would be if it was separate and attached to the car through a cable or some sort. Energy is energy, it has to go somewhere.

? What ?