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A Toy
Read 1841 times
August 06, 2015, 04:05:26 PM
Function

This is a “toy” regardless of the physics used showing a prop assembly taking flight, it’s only powered by a wound up rubber band much like a model airplane is but its energy is within its handle, acting on the 5 bladed propeller assembly. The operator willfully releases its energy by depressing the trigger disengaging the radial ratchet - setting the prop assembly unwinding. 

The 2 magnetic discs shown separate only after the prop thrust exceeds the magnetic attraction; the potential strong magnet’s attraction works to hold the prop axially in place –the incrementally weakening needed by placing multiple adhesive plastic disc shims separating the two magnets for its working attraction that’s initially unknown (at the time).  3 fixed pins drive the props radially ‘till the pins naturally withdraw out of their respective holes as the prop rises thereby freeing the prop from the launcher pad on its free flight. 

If an option (shown below) having LED’s on the prop ring are switched on only during flight -powered by hearing aid batteries- experiencing centrifugal force causing axially sliding of the battery casing outwardly making contact on the two LED leads while spinning, the leads are normally isolated by a adhesive donut disk atop the battery, the battery is captured in a loose housing permitting its movements. A gentile, molded in beam (spring) must be overcome by the centrifugal force generated only while the prop assembly is quickly rotating enough, but the beam acts to “reset” again to a “no-contact condition” anytime the prop assembly is at rest.

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* August 06, 2015, 04:33:02 PM
#1
Very nice work Bob, model looks great and the LED is an interesting idea, not something I would have thought of.

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* August 06, 2015, 05:11:32 PM
#2
Looks like fun.

Henry H

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August 06, 2015, 06:00:04 PM
#3
That is terrific Bob! Great job on the design and the render.


* August 09, 2015, 06:54:40 AM
#4
Bob, you lost me with, "...centrifugal force causing axially sliding of the battery casing outwardly..."

Henry H

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August 09, 2015, 09:38:32 AM
#5
Henry:

Imagine a centrifuge like NASA’s - the object is pulled outwardly from the center of gyration while it gains in weight (G’s) depending on rotation speed, I know there’s a formula somewhere that describes that conversion, but couldn’t find that off hand.  Does anyone know what that might be?

Thanks,

Bob

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* August 09, 2015, 10:13:52 AM
#6
Henry:

Imagine a centrifuge like NASA’s - the object is pulled outwardly from the center of gyration while it gains in weight (G’s) depending on rotation speed, I know there’s a formula somewhere that describes that conversion, but couldn’t find that off hand.  Does anyone know what that might be?

Thanks,

Bob

Threw me off when you wrote "axially" instead of "radially."

The formula is F = m*R*(omega)^2, where F is the radial force felt by an object rotating about some central axis (pounds in English units), m is mass of the object (slugs, or weight in pounds divided by 32.2), R is distance of the object's center of gravity from axis of rotation (feet), omega is angular velocity in radians per second (revolutions per second multiplied by 2 pi).

An equivalent formula is F = m*(V^2)/R, where V is tangential velocity of the object's C.G. (in feet per second).

Henry H

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August 09, 2015, 04:14:26 PM
#7
Henry:

I got it, thanks a bunch! I’ll use that data after weighing the small battery accurately. Sorry I misspoke causing the “defugalty”.  Also busy looking into recumbent trikes taking free time, Catrikes® in particular, balance is not a big issue - so I’m told - that’s a real plus.

Thanks again,

Bob

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