What is Helicopter: Definition and 205 Discussions

A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally-spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of VTOL (Vertical TakeOff and Landing) aircraft cannot perform.
In 1942 the Sikorsky R-4 became the first helicopter to reach full-scale production.Although most earlier designs used more than one main rotor, the configuration of a single main rotor (monocopter) accompanied by a vertical anti-torque tail rotor has become the most common helicopter configuration. Twin-main rotor helicopters (bicopters), in either tandem or transverse rotors configurations, are also in use due to their greater payload capacity than the monorotor design. Coaxial-rotor helicopters, tiltrotor aircraft, and compound helicopters are all flying today. Quadrotor helicopters (quadcopters) were pioneered as early as 1907 in France, and other types of multicopters have been developed for specialized applications such as drones.

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  1. S

    Girl falling out of helicopter - kinematics

    A girl in a helicopter falls out when it was rising vertically at 10 m/s. The girl has a rope tied to her harness so she can be retireved. After 2.5 secs, how much rope has been pulled out of the helicopter? I know that this is essentially asking you to find the height that the helicopter...
  2. K

    Helicopter blade energy physics problem

    [b]1. A helicopter has two blades , each of which has a mass of 240 kg and can be approximated as a thin rod of length 6.7 m. The blades are rotating at an angular speed of 45 rad/s. (a) What is the total moment of inertia of the two blades about the axis of rotation? (b) Determine the...
  3. F

    I want to build a single person helicopter.

    i want to build a helicopter at my home. i only have a wish, whaich is referred to as idea in physics. can some one tell me the guide points about it. the helicopter should be able to hold a single person or about 70 kg. i am in Pakistan, Karachi. i have no idea where to get all the equipment...
  4. B

    Question from a helicopter pilot. .

    Hi. Please excuse me if this is just too banal for this site, but we have a long-standing "real-world" problem that we need answers for and I am smart enough to know that I need to ask others ( = you guys ) for help. We normally carry up to 19 passengers but, during training and occasionally...
  5. S

    When Does the Package Reach the Ground?

    Homework Statement A helicopter is ascending vertically with a speed of 5.5m/s. At a height of 100m above the Earth, a package is dropped from a window. How much time does it take the package to reach the ground? Homework Equations delta y = Vot + 1/2at^2 The Attempt at a Solution...
  6. C

    Helicopter Physics: Finding Time to Reach Ground from Release Point

    Homework Statement The height of a helicopter above the ground is given by h=2.55t^3, where h is in meters and t is in seconds. At 1.85 s, the helicopter releases a small mailbag. How long after its release does the mailbag reach the ground? Homework Equations The Attempt at a...
  7. K

    Is the Russian Helicopter Death Ray Based on Multi-Beam Klystron Technology?

    hi i was wondering about the russian helicopter death ray and if it was based on the russian multi beam klystrons and all in one technology. does it use tesla multi beam technology? thanks
  8. R

    Can a Man Stop a Helicopter Taking Off?

    Well at work today an argument arose - me and one other person disagreed with about 12 others...and the thing is I can't seem to see how they'd be right. What I want to know is - could a man stop a helicopter taking off? The people I'm disagreeing with seem to think he could if he was...
  9. C

    Calculating Lift Force of Helicopter Propellers

    Homework Statement A 5400 kg helicopter accelerates upward at 2.17 m/s2. The acceleration due to gravity is 9.8 m/s2. What life force is exerted by the air on the propellers? Answer in N. Homework Equations Fnet=ma The Attempt at a Solution I am making the acceleration positive...
  10. R

    Speed of a helicopter determined by sonar

    Homework Statement A helicopter flies directly toward a vertical cliff. when the helicopter is 700 m from the cliff face it transmits a sonar signal. it recives the reflected signal 3.4 s later. if the signal travels at a wind speed 350m/s, what is the speed of the helicopter. The Attempt...
  11. B

    Newton's Laws of Motion on a helicopter

    Homework Statement A 12000- kg helicopter is lifting a 4000- kg truck with an upward acceleration of 0.9 m/s2. Calculate the force the air exerts on the helicopter blades. Homework Equations F = ma The Attempt at a Solution I have no idea! Please help!
  12. B

    Calculating the Force on a Helicopter in Flight

    Homework Statement A 13000- kg helicopter is lifting a 7100- kg truck with an upward acceleration of 2.1 m/s2. Calculate the force the air exerts on the helicopter blades. Do I use the apparent weight equation for this? Wapp = m(g + ay)
  13. V

    How Long Does It Take for a Released Mailbag to Hit the Ground?

    Homework Statement The height of a helicopter above the ground is given by h=3.00t^3, where h is in meters and t is in seconds. After 2.00s, the helicopter releases a small mailbag. How long after its release does the mailbag reach the ground? Homework Equations d=v_1t +...
  14. H

    Calculation of downwash of helicopter

    Hi everyone, I am doing the research on helicopter aerodynamics. By applying the blade element theory and momentum theory we can determine the induced velocity at the balde, and we knew that, at a distance very far below the rotor, the induced velocity is two time of the corresponding value at...
  15. 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...
  16. H

    Need Materials for Stability and Control Helicopter

    Need Materials for "Stability and Control Helicopter" Hi everyboy ! I'm now very disappointed, it's beause I have googled the materials of "stability and control helicopter" and what I got is nothing but disapointment. So, I need your help for the materials. Is there anyone got them ? please...
  17. B

    Can you help me understand helicopter aerodynamics?

    Hi, I have some questions about helicopter aerodynamics. I have been searching the web (and this forum) up and down but I could not find the answer. Maybe you can help. I want to calculate the cruise and maximum speeds of a helicopter given the weight, motor power, height (assuming pressure...
  18. T

    Rotation Kinetic Energy of Two Helicopter Blades

    A helicopter has two blades (see figure), each of which has a mass of 230 kg and can be approximated as a thin rod of length 6.7 m. The blades are rotating at an angular speed of 41 rad/s. (a) What is the total moment of inertia of the two blades about the axis of rotation? (a) Determine the...
  19. R

    Calculating Helicopter Downwash Force on a House Roof at 700ft?

    Does anyone know how to calculate how much downwards force a helicopter would exert on the roof of a house if it hovered over it at 700ft? Thanks
  20. F

    How would you determine the Lift(thrust) force of a Helicopter in hover

    I know the lift force equation is .5*rho*V^2*Area*Coefficient. But I was wondering in the real world how would you measure the lift force? I hope they don't just plug the values for the equations.
  21. R

    Helicopter Rescue Device - real application

    I'm doing background research on a real application. At high altitudes (and/or when people are shooting at you) helicopters can't stop and hover, but could snag a survivor or critically injured litter patient at around 30 knots (15 meters per second) A similar device (Fulton Recovery system)...
  22. X

    Could you pull down a helicopter?

    Me and a friend are having a dispute after watching the movie Underworld : Evolution. There's a scene in the movie where a character literally pulls a helicopter out of the air by pulling its fast rope straight down. Now I know it's Hollywood, but I started laughing at the reality of such an...
  23. S

    Helicopter Questions - Get Answers Now!

    I know this is not as serious of a topic as you are all used to, but hopefully someone could help me out anyways? - Imagine a helicopter hovering inside a cargo jet, (the jet is flying at cruising speed). What would happen to the helicopter if it was pushed outside the jet, with no changes...
  24. T

    How Is Lift Force Calculated for a Helicopter?

    A 4600 kg helicopter accelerates upward at 2.0 m/s^2. What lift force is exerted by the air on the propellors? I don't know how to do it. Please help :confused:
  25. A

    Limit word problem- helicopter jump

    Hi, I need help with this question At a publicity event, Ayida, a stuntperson, will jump out of a helicopter with a jetpack on her back. The jetpack allows her to achieve a net upward acceleration of 4.4m/s^2 for a single interval of maximun length 10s. Ayida wants to time the use of the...
  26. F

    A military helicopter dropa BOMB

    A military helicopter on a training mission is flying horizontally at a speed of 65.0 m/s and accidentally drops a bomb (fortunately not armed) at an elevation of 250 m. You can ignore air resistance. How much time is required for the bomb to reach the earth?(s) How far does it travel...
  27. M

    Helicopter Forces: What Force Keeps Helicopter Aloft?

    In a free-body diagram of a helicopter carrying a suspended object, what force exists to keep the helicopter aloft? Is there a normal force from the rotors? Any help would be appreciated.
  28. J

    Helicopter Parenting Effect on University Education

    Parents meddling in student life http://news.bbc.co.uk/1/hi/education/4777053.stm It's likely to be a new phenomena in the UK since the introduction of fees - and a lot of parents paying for their kids to go to uni. For you US people, is it a common practice, if a parent pays for their...
  29. M

    Calculating Drop Time from 105m in a Helicopter

    I need some help with a question please. If a helicopter has a speed of 5.50m/s moving upward vertically and when at the height of 105m above Earth a box is dropped from the window how much time will it take to reach the ground?
  30. J

    Need info on how do helicopter stay on the same place with res to earth

    Hi all I am Abhishek Jain, recently joined this group. I have one query which might have been previously asked/explained, but I still have problems in understanding it. I assume that the Earth is spinning clockwise at 1000 miles per hour. Suppose a helicopter is traveling anticlockwise to...
  31. W

    Can a Helicopter Fuselage Exhibit Pendulum Behavior?

    Hi, my first post to this forum: I'm curious whether the hanging mass of the fuselage beneath a helicopter rotor can be said to exhibit pendulum behavior. Specifically, in the case of a helicopter or other rotorcraft with a so-called teetering rotor, no torque is present at the rotor head...
  32. I

    Homemade Helicopter: For the People.

    Ok, I heard that you could make a cheap, but good helicopter, that's a 1-2 seater, relatively easy. How could this be done?
  33. A

    Helicopter Downwash: Strength, Lift, Air Viscosity & More

    Hello! We all know that helicopters can hover, stand still in the air. As they do this, a powerful downwash, down-directed wind, results. This is very obvious when the helicopter is near the ground, since the downwash often kicks up a dust cloud. My question is this: How strong will this...
  34. P

    Velocity of mail bag released from helicopter

    A small mail bag is released from a helicopter. The helicopter is rising with a constant speed of 1.5 m/s After 2.0 seconds, what is the VELOCITY of the mailbag? I use the equation Vf = Vi + a*t and a would be 9.8 m/s squared right?
  35. E

    Helicopter Problem: Calculating Lift Force on Rotors

    There were two posts reltaed to this question but both of them are so contradictory; the question goes a 13,000kg helicopter accelerates upward at 0.41m/s^2 while lifting a 900kg car. to the nearest Newton what is the lift force exerted by the air on the rotors? now one post would be...
  36. H

    Can a Homemade RC Helicopter Fly with Chainsaw or Lawnmower Engine Power?

    Hi all! All the way from Sweden comes a small question... Planning to build a simple RC helicopter which, in the first stage, only should be able to take off. My idea was to use either a small lawnmover engine, or one from a chainsaw and build the helicopter with two props, turning opposite...
  37. Integral

    What to do with a used helicopter jet engine?

    For those with a strong death wish only.
  38. V

    Solving the Helicopter Problem - What is the Answer?

    This problem led to a debate in my physics class, which was never resolved. A helicopter holding a 70kg package from a rope 5m long is accelerating up at a rate of 5.2 m/s^2. Neglect air resistance. When the upward velocity of the helicopter is 30 m/s, the rope is cut and the helicopter...
  39. Q

    Helicopter in a Moving Train: Will it Crash or Stay in the Air?

    Hi, Can someone help me out on this one ... A train is driving from one point to another at a constant speed. In the gangway of this closed train we let a RC-helicopter take off from the ground. What will happen with the helicopter, will he stay in the air near us or will he crash...
  40. A

    Edited to add:Helicopter Takeoff Formula: The Secrets of Insect Flight

    Can you give me the formula for taking off a helicopter? This formula must give the minimum force that produced by moth for taking off. :rolleyes: (i want to project a miniatur helicopter).Thanks... from eng. student
  41. T

    Helicopter final velocity help

    Okay...I am think that I am totally lost on this problem. A helicopter holding a 70-kilogram package suspended from a rope 5.0 meters long accelerates upward at a rate of 5.2 m/s^s. When the upward velocity of the helicopter is 30 meters per second, the rope is cut and the helicopter...
  42. Ivan Seeking

    Helicopter attacked with bows and arrows

    http://news.bbc.co.uk/2/hi/south_asia/4144405.stm This reminds me of some rare WWI film footage that shows the calvary charging on their horses, right along side the first tanks - a unique and brief moment in history, and certainly funny looking from our point of view. :biggrin:
  43. A

    Create a small model of aircraft or helicopter 30-50 cm long

    Hello I want create a small model of aircraft or helicopter 30-50 cm long which can fly for 3-4 minutes just as a hobby how should i go about? Thanx
  44. M

    Decoding Helicopter Movement: The Equation Behind Vertical Flight

    Well, I know this Q might look cheesy or silly...but: What is the major equation which decides if X disc with Y raduis with Z angular acceleration will carry M mass and "fly" with it...I am just concern about vertical movements...not the horizantal...Basically its about a hgelicopter moving in...
  45. 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...
  46. S

    Helicopter Lift Force Calculation

    A 7850 kg helicopter accelerates upward at 0.545 m/s^2 while lifting a 1250 kg car. What is the lift force exerted by the air on the rotors? What is the tension in the cable ignoring its mass that connects the car to the helicopter? Net Force = ma, so I did (7850)(0.545) + (1250)(0.545) =...
  47. A

    News Apache helicopter fires on crowd

    This was on our news this evening. They showed film of a US Apache helicopter firing on a crowd of civilians. Since a news cerw was right there, we saw the reporter get hit and die right in front of the camera, just as others around him also died. Also...
  48. 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...
  49. H

    Calculating Ball Velocity Dropped From Moving Helicopter

    This might be a stupid question, but if a helicopter is moving at 5.0 m/s vertically, and one drops a ball off the helicopter, what is the original velocity of the ball?
  50. K

    Can a Helicopter Land Safely with Power Failure?

    Can a helicopter that has lost power to the main rotor blades land slowly enough so that nobody gets hurt? What would the terminal velocity of a freefalling helicopter be?
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