Propeller Definition and 145 Threads

A propeller is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral, that, when rotated, exerts linear thrust upon a working fluid, such as water or air. Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are specially shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. Most marine propellers are screw propellers with helical blades rotating on a propeller shaft with an approximately horizontal axis.

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  1. K

    Propeller Slipstream & Tailplane Instability

    Is the effect that the propeller slipstream (i.e the helix) hits the tailplane causing much instability quite significant such that if u are using a tractor propeller a single rudder won't work creating the need for two rudders away from the slipstream path??
  2. A

    Can a propeller driven aircraft break the sound barrier?

    Hope this is the right place for this question, but it is very inetresting to me so I wanted to ask some experts. Can a propeller driven aircraft break the sound barrier? My answer, no. Any opinions will help Thanks
  3. F

    How can I calculate the pitch of a hovercraft propeller

    How can I calculate the pitch of a hovercraft propeller, what variables do I need? How do I know how many blades must I use to get the ultimate end result?
  4. 3

    Propeller Efficiency Report: What to Include & Refs

    i will make an report about the propeller efficiency can anyone help me and tell me the things i need to put in this report and the references i can use
  5. M

    Can Propeller Efficiency be Calculated from Scratch?

    Now i am doing study on vessels propeller efficiency which i can determine the best time to do propeller polishing.Do anyone have any idea on how do i calculate this propeller efficiency
  6. 3

    Investigating Propeller Slipstream Effect on Aircraft Tail

    could anyone help me in that please? i want to to detmine the effect of the propeller slipstream on the horizontal tail the aircraft is pusher and the propeller in front of the horizontal tail the distance is 15cm and the propeller diamter is 40cm or anyone help me with references
  7. J

    The drag force acting on a propeller?

    Hi, I am a university student of physics and currently have a project in which a "car" is propelled using only the energy stored in a balloon. Two possible ways of storing energy in the balloon are to inflate it and allow it to blow air out of the neck, or to twist it around and allow it to...
  8. T

    A ship's propeller shaft transmits 7.5 MW at 440rev/min.

    1. A ship's propeller shaft transmits 7.5 MW at 440rev/min. The shaft has an external diameter of 230mm. Calculate the maximum permissible bore diameter if the shearing stress in the shaft is to be limited to 150MN/m squared. The modulus of rigidity for the shaft material is 79 GN/m squared...
  9. A

    Pulse Jet Propeller Thrust Calculation

    Hello everyone! I recently visited the Air Force museum in Ohio and saw their Pulsejet Helicopter. It was intriguing how they attached a pulsejet to the end of each propeller tip. Since then, I’ve been wondering if two pulsejets could be used on a general aviation propeller. I’d like to...
  10. J

    Propeller airplanes vs jet airplanes

    why propeller airplanes have superior take-off performance than jet airplanes?
  11. R

    Spinning propeller cause a plan to yaw while it is taxiing?

    Hi Everyone, There is something I am having trouble I am understanding. Why does a spinning propeller cause a plan to yaw while it is taxiing? Also, how does the flow behind a propeller effect the performance of the control surfaces on the tail? Does it have any effect? Because the flow...
  12. D

    Variable Pitch Propeller mechanism?

    I need to study about the variable pitch propeller and its mechanism of adjusting the angel of the blades. And also about the materials used to make propellers and their benefits.. can someone please help me to find sources such as images/videos about the variable pitch propeller? or...
  13. V

    How calculate propeller efficiency if I know propeller trust?

    How calculate propeller efficiency if I know propeller trust ant motor power and motor efficienty?
  14. T

    What is the equation for approximating propeller thrust at a known RPM?

    Is there some equation i can use in order to approx. find the trust created by a prop at a known RPM?? -Tom
  15. C

    Does Water Depth Affect Marine Propeller Resistance and Cavitation?

    Is there a noticable diffence in torque required to spin a marine propeller at a constant rpm (say 2000rpm) when under a different water column? (5m vs 35m)
  16. M

    Magnetic Liquid Screw Propeller

    Is it possible or will it be possible to keep some magnetic liquids in some desired geometry and use as a traditional screw propeller ? Is it patented or visioned before ? Best regards , Mustafa Umut Sarac Istanbul
  17. C

    Rotational Kinetic Energy of an airplane propeller

    Homework Statement An airplane propeller is 2.02 m in length (from tip to tip) with mass 127 kg and is rotating at 2300 rpm about an axis through its center. You can model the propeller as a slender rod. a)What is its rotational kinetic energy? b)Suppose that, due to weight constraints, you had...
  18. J

    Propeller Rotation Problem - Please check

    Thanks in advance - it went smoothly so I'm hoping I'm right but... usually that's when I've made a big mistake. Homework Statement An airplane propeller is 2.08 m (tip to tip) and has a mass of 117 kg. When the engine is first started it applies a constant torque of 1950 N m to the...
  19. G

    How to Design an Efficient DIY Propeller for a Homemade Car?

    Hi, I need to make a propeller using either soda bottle plastic or cardstock. I think I can come up with a mechanism to spin it with a rubber band, but, I need an efficient propeller that creates enough power to move the car I am building. Any ideas/possible designs?
  20. 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?
  21. R

    Airplane propeller and plane's velocity relative to the ground.

    [SOLVED] Airplane propeller and plane's velocity relative to the ground. Homework Statement An airplane propeller rotates at 2200 rev/min while the airplane flies at a speed of 550 km/h relative to the ground. The plane's velocity is parallel to the propeller's axis of rotation. Part a)...
  22. M

    What factors affect the performance of marine propellers?

    Good day I hope someone can help. I am looking for marine propeller theory. Things like how do the diameter of a prop determine the speed of a vessel ? What effect does the blade angle or shape for that matter have on the functionality of the prop. If someone can help with the theory behind...
  23. clope023

    Angular acceleration of a Propeller

    [SOLVED] angular acceleration of a Propeller Homework Statement An airplane propeller is rotating at 2000rev/min . \omegaz = 209rad/s How long in seconds does it take for the propeller to turn through 40degrees? Homework Equations \theta = 1/2\omegat \omegaz = d\theta/dt...
  24. R

    Using a Stroboscope to Make a Propeller Appear Stationary

    Homework Statement A stroboscope is a light that flashes on and off at a constant rate. It can be used to illuminate a rotating object, and if the flashing rate is adjusted properly, the object can be made to appear stationary. (a) What is the shortest time between flashes of light that...
  25. A

    Airplane Propeller: Rotational Kinetic Energy & Angular Speed

    Homework Statement An airplane propeller is 1.85 m in length (from tip to tip) with mass 97.0 kg and is rotating at 2300 rpm (rev/min) about an axis through its center. YOu can model the propeller as a slender rod. What is its rotational kinetic energy? Suppose that due to weight...
  26. R

    Propulsion system for a single engine propeller driven a/c

    for my design project, i have to consider a feasible prop systm for a single engine propellr driven aircraft and I am thinking about diesel engines. they seem very efficient and cheap for aircraft propulsion. ill have a small number for power/ weight ratio but it will be cheaper and it wll use...
  27. N

    What is the Most Efficient Propeller Design for a Peddel-Powered Water Craft?

    hey guys, urgently need your help, I am an industrial design student and at present we have a project that involves designing and constructing a peddel powered water craft. there will be a race upon completion of the craft therefore it needs to be reasonably fast. If you have any...
  28. A

    Dynamic & Static propeller pressure

    Hey, I have this theory about static and dynamic pressure generated by a propeller, but I might be wrong, so I could use some comments on this. Its kinda long and whiney, but well.. here goes; Lets say I have a motor with propeller, spinning at a certain rpm. -In the first scenario, I put the...
  29. A

    From theoretical airflow speed of rotating propeller to a realistic value?

    Hey, Yet another propeller question on this board. I have done my research, both here & on google, but I cannot seem to find an answer. Lets say I have a motor on which I mount a propeller. This motor is static (not moving like on a flying airplane), so say its a small ventilator...
  30. kach22i

    Fan & Propeller shapes: Sickle and Curved

    Air or Water: I'm looking for information on fan and propeller shapes (ducted and non-ducted) which might lead to more quiet if not more efficient shapes. Noise is lost energy just as heat is lost energy in a mechanical system, right? I have a thread which contains many bits of...
  31. A

    Understanding Propeller Pitch: Definition, Function, and Stalling Explained

    "Pitch is defined as the theoretical forward movement of a propeller during one revolution — assuming there is no "slippage" between the propeller blade and the water" i dont, kinda, really get this definition of the pitch. i searched it at so many sites. they all say the same thing, like pitch...
  32. S

    Need help on Aluminum propeller

    I need to contact who ever would be authority on propeller design and applications. In short, the Idea is to build a Aluminum prop, 1.2 meters diameter with weight of about 1000 grams. Targeted application would be primarily for powered para gliders. I need some arguments for and against...
  33. S

    Toy Propeller Efficiency: Range of Efficiencies

    Question: what is the range for propeller efficiency for plastic toy propellers?
  34. P

    Design a Propeller for Physics Project

    I have a physics project where I am supposed to make a car from index cards, manilla folders, paper clips, drinking straws, glue, tape, rubber bands, etc. I am attaching a propeller to the back, but I need a decent design i can make by cutting and bending a manilla folder. It should not be more...
  35. P

    Make a Manilla Folder Propeller for Physics Project

    I have a physics project where I am supposed to make a car from index cards, manilla folders, paper clips, drinking straws, glue, tape, rubber bands, etc. I am attaching a propeller to the back, but I need a decent design i can make by cutting and bending a manilla folder. It should not be more...
  36. P

    Design a Propeller with Manilla Folder: Physics Project

    I have a physics project where I am supposed to make a car from index cards, manilla folders, paper clips, drinking straws, glue, tape, rubber bands, etc. I am attaching a propeller to the back, but I need a decent design i can make by cutting and bending a manilla folder. It should not be...
  37. M

    What Torque and Power is Needed to Spin a Propeller at a Given Speed?

    :confused: I am working on a project where I need to understand flight physics. I am having some trouble getting the whole torque vs power vs thrust thang. I'm basing my project off a existing ultralight, the LightSport Ultra from Free Bird Innovations. Here are the specs: 530lbs...
  38. J

    Force of friction of this cart on wheels with a motor driven propeller

    can anyone show me how to solve this problem? a cart on wheels with a mass of 250 g has a motor driven propeller with a force P of .3 N, and it moved down an incline of 30 degrees with an acceleration of 3.5 m/s^2. What is the force of friction ? determine coefficent of friction
  39. J

    Cart with propeller - Find force of friction

    can anyone show me how to solve this problem? a cart on wheels with a mass of 250 g has a motor driven propeller with a force P of .3 N, and it moved down an incline of 30 degrees with an acceleration of 3.5 m/s^2. What is the force of friction ? determine coefficent of friction
  40. K

    Solve Propeller Problem: Average & Instantaneous Power Output

    An airplane propeller is 2.08 m in length (from tip to tip) and has a mass of 117 kg. When the airplane's engine is first started, it applies a constant torque of 1590Nm to the propeller, which starts from rest. Question I: What is the average power output of the engine during the first...
  41. A

    Finding the lift of a propeller

    Is there any formula to find the lift genetated by a helicopter propeller?
  42. S

    Exploring the Effects of Propeller Placement on Wing Lift

    If the propeller is placed in front of wings and since the job of the propeller is to accelerate the airflow, wouldn't it result in faster airflow around the wing resulting in increased lift?
  43. D

    Marine Propeller Shaft Flange Design

    First of all this is for marine duty. Iam using a Gear which supplies the shaft flange good for shafts up to 4" in diameter but iam restricted to use a 4.5" shaft. In this case i have to design the flange .. iam struck here could anyone of you please guide me .. how to find out the flange...
  44. L

    Angular velocity of airplane propeller

    here is the problem: An airplane propeller is 2.08 m in length (from tip to tip) and has a mass of 117 kg. When the airplane's engine is first started, it applies a constant torque of 1950 N*m to the propeller, which starts from rest. -What is the angular acceleration of the propeller...
  45. A

    How Does Propeller Size and Placement Affect Water Surface Speed?

    Water Propeller -- General physics questions Howdy, I have been following the boat bike concept for a few days and am interested in finding out more on how to get better water surface speed. The props on these bikes look small and the specs are touting no more than 10 km/h. Can anyone...
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