This is not a specific question but it might make for some interesting technical questions and answers.
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The World’s first manned flight of a 100% electric powered helicopter was conducted on the 12th of August 2011, after 2 weeks of tethered flight tests. This machine...
The desire is to insert a press-fit aluminum tube inside a stator laminate stack on an outrunning PM motor. http://www.unicopter.com/1952.gif The intention is to use this aluminum tube as a heat sink for the motor. A heat transfer compound (probably non-silicone) will be pasted between the...
Is it possible to drive two mechanically unconnected brushless PMDC motors from a single controller? The idea is for both motors to have their own Hall effect sensors. Their signals would be feed to a sort of comparator-timer where the mean-time of the two signals would be added to the time...
The intention is to have numerous bolt-holes located at a constant radius around the ring of the laminates in a stator. Then bolts will be inserted in these holes to hold the laminates together and to attach the stator to the supporting structure.
My concerns are;
~ Will steel bolts...
I would like to read the percentage of the PWM ON-time during the running of a Brushless DC Permanent Magnet motor that has a Star 3-phase configuration.
Is the wiring in the diagram below a viable way of achieving this? The resistance will be 1/2 that used for an identical voltmeter on the...
The following assumes the application of a constant DC current to rotors that have no rotational inertia to start with.
Some illustrations show the flux from the pole of a permanent magnet causing rotation by 'pulling' the laminate core of a coil wound electromagnet into alignment with the...
I am interested in the potential risk of flutter in a composite rotorblade that will be very rigid and resistant to in-plane and out-of-plane bending [carbon tow in the spanwise direction], but will be quite flexible in respect to rotation about the pitch axis [fiberglass tow in the chordwise...
Sikorsky's patent attorney and a few of Sikorsky's current and previous employees are the Correspondent and the Inventors of the filed US Patent Application 20090140095 for 'ELECTRIC POWERED ROTARY-WING AIRCRAFT', dated November 30, 2007 and January 23, 2008. All of the claims should be of...
Does anyone know of a supplier that offers quad-thread worm & wheels that are larger (stronger) than a 6 diametral pitch? The required ratio is approximately 7.5:1.
Thanks;
This post relates to a VTOL concept and not a specific engineering question. Should this violate the policies of Eng-Tips, I will understand the reason for its removal.
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The Web page http://www.unicopter.com/1471.html presents a concept that is theoretically an...
Is it correct to say that, given a common set of criteria, a heavier (larger) motor will provided a greater power/weight ratio then that of a smaller motor?
The criteria would be that of a modern high performance motor that is brushless, has rare earth magnets and perhaps is an outrunner...
Does anyone have any information related to a non-simultaneous rotor passage through the vortex ring state?
Of specific concern is the possibility of roll in a helicopter with side-by-side rotors.
Thanks
Dave J
Is there a manufacture that produces spiral bevel gears with a ratio of 4:1 or larger?
The diametral pitch will be 12 or 10 and it will be preferred if they are Aerospace quality.
Thanks
Dave
The http://www.UniCopter.com/ElectrotorPlus.html consists of a 2-bladed rotor where the rotorhub has hub springs, or alternatively, offset teetering hinges, plus a control moment gyroscope; for enhanced cyclic control, particularly during zero-gravity.
The intent of this posting is to place...
Can anyone advice the name of companies or individuals who would be willing to develop, prototype and produce two custom outrunner electric motors of 15 hp each?
Thanks.
Dave
I have a situation where the Angular Momentum of a ring is known and I wish to apply a sinusoidal force, parallel to the primary axis of rotation, on this ring. The frequency of this force is constant, however the amplitude may vary. The unusual aspect is that the gyroscopic is not allowed to...
Can anyone provide information on a means of mechanically creating a phase lag? The lag will always be 90-degrees, however, the amplitude of the 'signal' will vary.
Thanks.
Dave J
I am interested in knowing if locating a body ahead of an actuator disk or behind an actuator disk has any effect on the aerodynamic efficiency. This body would have a 3D-teardrop shape and additional items, which would contribute to drag, are not considered.
A sketch and additional comments...
Excluding the patents, does anyone know of any sources of information or actual products related to worm & wheel reducers that use balls (or rollers) between the two rotating members?
Thanks.
Does anyone know of any sources of information related to the, lift, drag, center of pressure etc. on airfoils when the airfoil is being subjected to reverse airflow. I.e. where the air stream is flowing from the [labeled] trailing edge to the [labeled] leading edge.
Thanks
