What is Rotor: Definition and 148 Discussions

ROTOR was an elaborate air defence radar system built by the British Government in the early 1950s to counter possible attack by Soviet bombers. In order to get it operational as quickly as possible, it was initially made up primarily of WWII-era systems, notably the original Chain Home radars for the early warning role, and the AMES Type 7 for plotting and interception control. The system had a network of control stations, mostly built underground, and connected with an extensive telephone and telex network.
Work also began on a new microwave frequency radar to replace Chain Home in the 1957 time-frame. However, an experimental system known as Green Garlic was so successful that it began replacing Chain Home starting in 1954. In service, these proved so accurate that they could replace the Type 7 radars as well, and their greatly improved range meant that far fewer radars would be needed to provide coverage over the entire United Kingdom. This led to the Master Radar Stations that filled both early warning and ground controlled interception roles. The original ROTOR plans for 66 radars was repeatedly reduced, ultimately only requiring half that number of stations.
ROTOR called for the continual upgrading of the network over time, both the radars and the command and control systems. The introduction of the carcinotron radar jammer in the mid-1950s was a serious blow to these plans; a single aircraft carrying a carcinotron could jam the ROTOR radars so completely that they were rendered useless. At the same time, the introduction of the hydrogen bomb and ballistic missile greatly changed the nature of the strategic threat, and over time the idea of whole-country defence became untenable; the only way to defend against missile attacks was deterrence, and if that failed, interceptor aircraft and missiles would have no measurable effect on the eventual outcome.
ROTOR was initially to be replaced by a new network dedicated largely to defending the V-bomber force, the "1958 Plan". But even this role was eventually abandoned, leaving only the task of locating aircraft carrying jammers in order to keep the BMEWS radars free from interference and prevent a successful sneak attack. Such a system did not require a large number of radars nor country-wide coverage. To reduce the cost of this much smaller network, studies on integrating the military radars with civilian air traffic control led to the Linesman/Mediator system of only five primary stations. The original ROTOR was replaced by Linesman in stages, starting in 1967.
A similar expedient system in the United States was the Lashup Radar Network.

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  1. H

    Rotor Tip Weight (Centrifugal Force)

    What formula would one use to determine the centrifugal force at the tip of a rotor of 35ft diameter, rotating at 392rpm? Would any other factors be necessary, such as blade thickness, weight, etc? A pilot I work with doesn't believe the weight at the rotor tip would be measured in tons. I...
  2. R

    Solving Rotor Ride Physics for a Monkey: Velocity, Friction, and More

    Homework Statement A rotor ride has a radius of 10 m. The ride is in its experimental phase, so the engineers have decided to use a monkey instead of a person. The mass of the monkey is 30 kg. The sides of the ride are designed so that the maximum friction riders will experience is 0.4*Fn...
  3. J

    Calculating mean radius of a gas turbine rotor (blade and hub)

    Homework Statement I'm having difficulty obtaining an accurate value possibly due to unit conversions. Homework Equations r_m=mdot/(2*pi*U*N) r_m=mean radius, ft mdot=mass flow rate, lbm/s U= blade velocity, ft/s N= RPM The Attempt at a Solution I know that I have to convert Rpm...
  4. F

    Helicopter Rotor Lift Equation

    Hello! I am creating, or at least attempting to create, a human-powered helicopter. I need an equation to figure out the lift from the rotors. I plan to use four counter-rotating rotors, three blades each, and each blade made of foam, with aluminum ribbing. The blades will be six feet each...
  5. T

    Engineering Derivation of normal and tangential forces of a rotor electric motor drives

    Hi all, I'm currently undergoing a masters of science course in Mechatronics Engineering. One of my core modules is Electrical Components. I'm stuck in understanding one of the key parts in this module. I've been asked to derive the Tangential and Normal forces of the rotor shown below. I've...
  6. N

    Why Squirrel cage rotor is short circuited?

    In a 3-phase squirrel cage induction machine, why the rotor terminals are short circuited?
  7. I

    Brake Rotor Heat: Calculating Temperature for 120kg Object at 30mph

    This isn't so much a homework question but rather something I need to know in order to design something. I need to know how much a brake rotor will heat up during braking. The force it needs to stop is a 120kg object traveling at 30 mph. I don't know any of the equations necessary to figure...
  8. S

    Engineering Question on induction motor rotor copper losses

    Homework Statement The rotor of a 3 phase 60hz 8-pole induction motor takes 220w @ 3hz. Find the rotor speed and the rotor copper losses. 2. The attempt at a solution I have found the rotor speed by using the equation slipspeed = fr(120)/P = 3hz(120)/8 = 45 rpm then finding nsync by...
  9. R

    Where Can I Find Resources for Calculating Rotor Forces During Auto-Rotation?

    Hello, Out of curiosity I've been trying to mathematically model the forces on a rotor during auto-rotation starting with the basic lift/drag equations used for analyzing basic fixed wing flight (i.e. our beloved L = 0.5*Cl*rho*A*v^2). At first I thought this shouldn't be too hard since it's...
  10. M

    Torque required to reduce the speed of a rotor?

    Hi, I'm currently trying to find out how to calculate the torque required to slow a rotor down from a high rotational speed to a low rotational speed. I know the inertia of the rotor, the 2 rotational speeds and the time it needs to take to slow the rotor down. Is there a method or formula...
  11. D

    How Does Excitation on a Rotor Affect Reactive Power Output?

    I know as a fact that excitation (amount of current on the generator rotor) determines the amount of reactive power output from the generator. But why? How does it turning the excitation up or down influence the reactive power output? Thanks.
  12. S

    Helicopter with Main Rotor Below the Cabin

    Overlooking the difficulty in landing such a craft, would a helicopter with the main rotor below the center of mass, differ significantly in stability from normal one with the main rotor above the center of mass?
  13. MotoH

    Blue Edge rotor blade (Eurocopter)

    Video: https://www.youtube.com/watch?v=dBS1NRsYuF8 Pretty cool. You can't beat the sound of a Huey though!
  14. A

    Helicopter rotor blade stress calculations

    Heyhey, I am currently doing my final year masters project which involves testing rotor blades. I am performing a stress analysis of the blades. I will be using FEA software, but I also need to do some hand calculations. I have been looking for formulas for a while now, but I am unsure which...
  15. N

    Simple way to amplify voltage to RC helicopter tail rotor?

    My brother bought a http://www.centrix-intl.com/details.asp?productid=4909" RC helicopter. It has a tail rotor which is mounted parallel with the ground and enables the chopper to go forwards or backwards. The helicopter goes backwards great, but it doesn't go forward too well. I would like to...
  16. S

    How to increase the abrasion resistance of rotor

    For Kaolin slurry filter presing we are using progressive cavity pumps.After three months of operation we found that the pumping rate is reduced a lot.Upon investigation we found taht this is because of the abrasion. 150 micron Chromium coating done, still after three months ,this again failed...
  17. A

    Rotor blade design problem for turbomachine

    Homework Statement Determine the camber angle of a rotor blade for an axial flow turbomachine. Homework Equations Beta1 - Beta2 = Camber angle (theta) The Attempt at a Solution http://img517.imageshack.us/img517/2965/blade.jpg If the camber angle is equal to beta1 minus...
  18. P

    Calculating Eigenstates and Eigenvalues of a 2D Quantum Rotor with Perturbation

    Hello! I need help with this typical quantum problem: I have a quantum rotor in 2 dimensions. And a perturbation along the x direction: Here's the unperturbed Sch equation: -\frac{\hbar^{2}}{2M}\frac{\partial^{2}}{\partial \phi^{2}}\psi(\phi)=E\psi(\phi) And here's the...
  19. A

    DC Brushless Motor Rotor Steps: 4 Poles North/South?

    Hello Forum, I have a 3 phases DC brushless motor from a Hard Disk Drive, when energize one coil and turning by hand the rotor i can feel 4 steps per rotation, is this means that this motor has 4 poles of north and south? Thank you in advance, Anita
  20. P

    Charged cylinder (electric field, rotor, divergence)

    Homework Statement Charged Cylinder has length L and radius a. Charge density increases within the equation rho = rho0(r/a)3 where rho0 is constant and r is distance measured from cylinder´s axis. Outside of the cylinder charge density is zero. a, Calculate the electric field inside and...
  21. B

    Rotor Dynamics Quantification HELP

    Hi, I'm a UT Mech E student about to graduate who's been tooling around with with some helicopter dynamics books for home machined RC contrarotating helicopter fun and I had some questions for any aerospace pros lurking around here. Being ME I know few aerospace guys so I've got some burning...
  22. T

    Steam Turbine / Tesla Turbine - bladless rotor in steam turbine?

    Hi everyone, I am looking into subject matter to use as my final year project at university. The Tesla Turbine is something that I have recently looked into. I am interested to know the following... In the Tesla Turbine, water is 'injected' and border interactions of the different molecules...
  23. H

    How do you seal a rotor underwater?

    Lets say I will be operating a generator underwater in a "box" sitting on the river floor. Turbine blades will be spinning a rotor attached to said generator, and obviously the turbine blades are exposed to the water and the generator is sealed in the box. I'm having trouble identifying what...
  24. B

    Calculating Lift Capacity of Rotor Blades

    What calculation is the to find the amount a helicopter (or flying device using rotor blades) can lift? I would of thought I would need to take into consideration the RPM of the blades, the size of the blades and maybe the angle. I was hoping there would be some calculation telling me how much...
  25. T

    Help with single-plane rotor balancing

    concerning a rotor with an imbalance, how does the angular velocity of the rotor affect calculations about the size and placement of the correction weight?
  26. P

    Helicopter tail rotor thrust requirement

    How can you calculate the amount of thrust needed by the tail rotor of a helicopter to counter the torque of the main rotor?
  27. X

    How fast must the rotor of a generator rotate?

    Homework Statement The maximum indicued emf in a generator is 205rpm is 43.0V. How fast must the rotor of the generator rotate if it's to generate a maximum inducded emf of 55.0V? Homework Equations E= NBAsinwt The Attempt at a Solution 205r/m*2 (Pi)/ 1rev81min/60s = 21.46rad/s magnet...
  28. W

    Gyroscopic effect on tilting rotor?

    Hello folks I've been a little confused - I'm currently designing a rotorcraft but I need to be able to predict the force (or torque) I'd need to tilt the rotor. What I've done is model the rotor as a simple rigid disc. I've attached the diagram below. what sort of behavior would I get during...
  29. M

    Synchronous Motors: Can Rotor Spin with 3-Phase AC Supply?

    Hi, I have a question about synchronous motors. If the DC field winding of a synchronous motor were to be replaced by a low-impedance short-circuited coil and the stator were to be supplied with 3-phase AC, would the rotor spin? If the answer is yes, would the rotor follow the direction of...
  30. A

    Electric motor with outer rotor

    I'm trying to find a DC motor with the rotating part on the exterior (the electromagnets and wires attached to the central axis) - something similar to a computer cooling fan or ceiling fan. It must be as powerful as possible for about 2 inches diameter. Any idea where I could find such a thing...
  31. B

    Disc brake effectiveness varies on rotor size?

    Hey - I am a bike mechanic with a large interrest in physics. I know that a larger disc brake rotor provides a greater braking effectiveness, but how can you mathmatically prove it by using physics formulas? And what formulas would be useD? Any ideas would be highly appriciated!
  32. J

    Integration help for helicopter rotor

    Hi, This is my first post here, but I've been enjoying the site for some time now. I've run into a snag with an equation I'm trying to develop. Its purpose is to help determine power requirements for radio controlled, model helicopter rotors: P = ( π2 Θ3 Cd ρ A / 2 ) ( R4 - r4 ) P =...
  33. mtworkowski@o

    Propeller vs. Rotor: Exploring the Differences in Aircraft Design

    I was thinking about the difference between the appearance of a propeller on a plane and a rotor on a helicopter. What is the consensus?
  34. Peeter

    Geometric algebra: longitude and latitude rotor ordering?

    [SOLVED] geometric algebra: longitude and latitude rotor ordering? Was playing around with what is probably traditionally a spherical trig type problem using geometric algebra (locate satellite position using angle measurements from two well separated points). Origin of the problem was just me...
  35. E

    Motion in a circle of helicopter rotor

    Homework Statement A model of a helicopter rotor has four blades, each 3.20m in length from the central shaft to the blade tip. The model is rotated in a wind tunnel at 600rev/min. a.) What is the linear speed of the blade in m/s? b.) What is the radial acceleration of the blade expressed as...
  36. C

    Solving S.E. for rigid rotor (asymmetric top)

    Hi, I'm looking to numerically solve the rotational Schrodinger eqn. for a molecule which I'm happy to treat as an internally rigid body. The molecule will be in an external potential, so it's not a free rotor. Does anyone have any advice or references for an easy derivation of the K.E...
  37. A

    Why is there no helicoptor with a single rotor?

    All helicopters have two rotors. Some have both rotors on vertical axes but rotating in opposite directions, and the rest have one rotor on a horizontal axis perpendicular to the helicopter body at the tail. Why is a single rotor never used? :frown:
  38. J

    Effective Methods for Securing a Rotor Disk to a Shaft

    Hello, I am wondering what the best (and simplest) way to secure a rotor disk to a shaft is. I have a 3" diameter Acrylic disk with a 0.375" hole drilled in it to accept a 0.375" diameter steel shaft. What do you all think? Thanks, Jason O
  39. wolram

    Straightening Bent Teeth on Rotor for Stator - Tanis Foodtec

    The picture is the rotor that runs in a stator with similar teeth, the stator is aprox 18 inches long and has 21 rows of teeth, if a forign object gets into this mixing head the teeth can bend makeing it imposible to disasemble, anyone have an idea how to straighten bent rotor teeth ...
  40. R

    Antigravity Rotor - New Patent

    See the web page: http://www.geocities.com/rolfguthma...ent/patent.html This new patent has the best explanation on the gravity anomaly observed of the experience accomplished by Eng. Russian Eugene Podkletnov in Tampere/Finland in 1996. See the site: Podkletnov's basic article (1995)...
  41. M

    Gyro Rotor Question. Can't figure it out Need help tonight if possible

    Gyro Rotor Question. Can't figure it out! Need help tonight if possible! I am taking a dynamics class which is reallly difficult. I've been able to solve all of the problems but this one. Can anyone help me by tonight? A rotor mounted in bearings spins about a horizontal axis as shown...
  42. I

    Multiple Rotor Motor: Possible or Not?

    what i mean by this is a basic dipole motor, but with two of them side by side set at different angles. it's kind of hard to explain. but try to think of a tripole motor, but with an extra pole. then keep both of extra poles at different angles than the other two (so maybe 90º apart, or smaller...
  43. S

    Moment of inertie of rotor blaes of a helicopter

    having some major issues with this unit, mainly since the homework was assigned and we haven't been lectured on it yet...so it's new to me. anyway, if anyone can help me out with this problem, that'd be awesome. -----A helicopter rotor blade can be considered a long thin rod. If each of the...
  44. G

    Calculating Rotor Revolutions for Space Probe Orientation Change

    The rotor of an electric motor has rotational inertia I am = 2.5*10-3 kg · m2 about its central axis. The motor is used to change the orientation of the space probe in which it is mounted. The motor axis is mounted along the central axis of the probe. The probe has rotational inertia Ip = 8 kg ·...
  45. W

    Helicopter rotor has four blades

    A model of a helicopter rotor has four blades, each of length 3.90m from the central shaft to the blade tip. The model is rotated in a wind tunnel at a rotational speed of 480rev/min . A.) What is the linear speed of the blade tip? given R= 3.9 T = 480 would it just be V= 2*pi*R/t...
  46. Clausius2

    Spherical Rotor: A New Vision for Electrical Machines

    When I took my courses on electrical machines, it always said about cylindrical rotors surrounded by cylindrical stators. Well, I have been thinking about situating the statoric electrical poles conveniently over an sphere surface. One technological application of this would be the next...
  47. D

    Finding the Radius of a Spinning Rotor: Can You Help Me Solve This Problem?

    Help with problem..."rotor ride" OK I was assigned this homework sheet on Uniform Circular Motion and Law of Universal Gravitation...and there is only one problem I can not get. If you could, please help me. Thanks in advance. Here it is: The "Rotor" ride is the one which presses you...
  48. M

    Rotor rooter and artifical gravity

    [SOLVED] rotor rooter and artifical gravity There is a ride in the carnival called the Rotor Rooter in which people stand up with their backs against a curved wall. This wall starts to move swiftly, spinning in a circular motion and then the floor drops out and a person finds themselves not...
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