1968

Item 1968

DESIGN: Electrotor-SloMo - Control - Flight - Auto-Collective by Torque-Pitch - Torque Reactor - Magnetic

Picture:

For now see 1893.html

Drawing:

DXF file of above drawing. 1968_TEST.DXF A test for quality with ungrouping.

The magnets will not have the 'Gap to Force plot' that springs of different lengths can offer.

This opposing torque may be complimented by the motor-rotor to aero-rotor elastomeric bearing.

See drawings on 1893.html and 1907.html.

There is a sketch on the hard copy of this page that has not yet been added.

Torque:

The force from the motor at full power and 5" radius is 270 lbs. From DESIGN: Electrotor-SloMo - Rotor - Hub - A - Torque Calculations.

Assuming that this could be trebled due to perturbations or overpowering the motor, or slow weakening of the magnets the maximum thrust should be considered as 810 lbs. Doubled would be 540 lbs.

If there are 12 magnets pairs in repulsion then the force between each pair must be 810 / 12 = 67.5lbs

Magnetic Force (PM) and Distance:

See suppliers specification page and forse-distance graph of selected magnets

Force between two magnetic poles: From Wikepidia

Classically, the force between two magnetic poles is given by: $F={{mu q_{m1} q_{m2}}over{4pi r^2}}$

F = (μq_m q_m2 )/4πr²

where

F is force (SI unit: newton)

q_m1 and q_m2 are the magnitudes of magnetic poles (SI unit: ampere-meter)

μ is the permeability of the intervening medium (SI unit: tesla meter per ampere, henry per meter or newton per ampere squared)

r is the separation (SI unit: meter).

The pole description is useful to practicing magneticians who design real-world magnets, but real magnets have a pole distribution more complex than a single north and south. Therefore, implementation of the pole idea is not simple. In some cases, one of the more complex formulae given below will be more useful.

"I have found some articles which say that magnetic force obeys the inverse square law, but this can't be used when I don't know where the poles are within the magnets. If I assume the poles are in the faces of the two magnets, then the inverse square law predicts a magnetic force of infinity if the two poles are touching! Can anyone help? "

Magnetic Force Deterioration:

Over time etc. one or more of the magnets will start loosing their magnetism. This loss will result in the pitch change being greater then that desired for the amount of power change.

I believe that, initially this will result in it taking longer for the change in RPM to replace most of the pitch change. Eventually, this loss of magnetism will result in the RPM being able to recover any of the pitch change.

Solution; At some time this magnetic force must be returned to its original value. It would appear that the replacement of one or more magnets (since the work in unison) will rectify the problem. In addition, it appears that it will be simpler to replace the magnet(s) then provide them all with positional adjustment.

Magnet - Buy:

This is a potential magnet:

K&J Magnets Inc. http://www.kjmagnetics.com/proddetail.asp?prod=BCC8%2DN52

Magnet - Mounting:

The magnets will always be in repulsion. Therefore they can be contained in a pockets

Shims could be placed in the back of the pockets and the repulsion between magnets will result in the magnet keeping the shim in the pocket.

Concern:

Will the flux of these magnets interact with the flux of the motor?

The magnets may result in a force that increases at an exponential rate that is greater than desired. I.e. too week at a distance and too strong when close.

Perhaps a long spring is the best. This will result in a reasonable amount of torque at the low RPM range before the pitch increases from its home position. This no pitch at low RPM might also allow one motor to provide some minimal amount of power to both rotors, say during autorotation, without causing the pitch of the blades on the powered rotor to increase.

Or ~ Perhaps the torque resistance of the main elastomer between the motor-rotor and the rotorhub will provide the additional pre-loaded resistance at the minimum pitch setting and thereby reduce the rate of the exponential increase

Will the magnets and there containment weigh too much?

Neodymium: ~ Atomic Weight = 144.24

Iron: ~ 470 lb / cubic foot, Atomic Weight = 55.847

Boron: ~ Atomic Weight = 10.81

(24 x .75 x ,75 x.5) = 6.75 cu-in 6.75 / 1,728 sq-in / sq-ft = 0.0039 cu-ft. 470 x 0.0039 = 1.833 lbs This is 4 lbs plus structure for the craft. What does the neodymium and boron do to the weight?

NdFeB permanent magnet of the main raw materials are rare earth metal neodymium (Nd) 32%, metals iron (Fe) 64% and non-metallic element boron (B) 1%

Relationship with:

DESIGN: Electrotor-SloMo - Control - Flight - Unique Collective by Torque-Pitch - Overview

Initially displayed: October 14, 2010 Last Revised: November 19, 2010

The above utility invention is openly and publicly disclosed on the Internet to negate an entity from patenting it, to the exclusion of all others whom may wish to use it. ~ Reference patent law 35 U.S.C. 102 A person shall be entitled to a patent unless - (a) the invention was known ... by others in this country, ..., before the invention thereof by the applicant for patent.