Questions tagged [propeller]

Aircraft propellers are airfoils which convert rotary motion from a piston or turbine engine into thrust suitable for propelling an aircraft.

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210 views

Do Constant maximum lift to drag ratio variable pitch propeller exist?

Are there variable pitch propellers, where pitch is set so that the blades constantly are at their maximum lift to drag ratio AoA, whatever the incoming relative wind speed & direction? Such a ...
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902 views

Is this equation for propeller thrust correct?

From dimensional considerations, and assuming that the power $P$ applied to a propeller of diameter $D$ moving at an axial speed $V$ is 100% converted to the acceleration of a mass of air with density ...
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277 views

What is the difference in performance between variable pitch prop and two fixed propellers for take-off and cruise speeds?

Push-pull configuration aircrafts usually feature identical engines and propellers working only in tandem for multiple reasons like higher speed, better climb rate, reliability, cost, ease of ...
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Do contra-rotating props have worse tip vortices than single props?

As I understand it, blades from a propeller have their own tip vortices, because the blades produce lift via the same aerodynamic principles as wings. So they must have tip vortexes too. So with ...
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285 views

What calculations are needed for counter-weight balancing on a propeller?

I am designing a small-scale propeller and i have managed to design on optimized geometry for the blade. However the blade pitch angle adjusts according to different flow speeds so i need to mount ...
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269 views

What Inertial effects should be considered to achieve blade stability on a Variable Pitch Propeller tailoredby aerodynamic loads?

I am developing a self adjusting variable pitch propeller tailored by its pitching moments due to aerodynamic loads setting the blade rotation axis in an offset from the aerodynamic center as shown ...
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174 views

Could this propeller work on a quadcopter and decrease the sound?

I came across a video yesterday that showcased a propeller design that looked very interesting. I am a regular drone flyer and I constantly look for exciting things to try out. Would this design in ...
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307 views

Can quadcopter-like UAVs ever get significantly quieter? Any candidate technology?

The light weight quadcopter and hexacopter UAVs that can cary say 2kg to 20kg payloads for "delivery" produce enough noise that a steady stream of pizza and book deliveries might not be so welcome in ...
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42 views

Relationship of propeller RPM, blade pitch, and drag at very low blade pitch angles

I'm researching the 2016 crash of a PIA ATR-42 in Pakistan, the report on which was recently released. Link to the report: https://www.caapakistan.com.pk/Upload/SIBReports/AAIB-386.pdf During the ...
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93 views

Is “V/n” geometric or effective pitch in advance ratio formula?

V is the freestream fluid velocity, typically the true airspeed of the aircraft or the water speed of the vessel n is the rotational speed of the propeller in revolutions per unit of time D is ...
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159 views

Could propellers benefit from the design of the Blue Edge rotor?

Source: wired.com If indeed the Blue Edge blades reduce noise by 50%, could the similar design be used on [forward-facing] propellers without a penalty in speed or agility?
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104 views

What airplane model was this historic propeller attached to?

I have a 9-foot historic wooden biplane propeller with brass edges. It does have a serial number, but it is tough to read. 2250 DN 152 6' 6" is what it appears to say. I am attaching a photo of it. ...
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45 views

Do open propellers experience pre-entry drag (additive drag) like an engine in nacelle?

Engines in a nacelle experience pre-entry (also called additive) drag. Do unducted propellers experience it too?
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62 views

What is the relation between solidity and lift coefficients?

I've seen this graph in a couple of places. I'm not sure what it's supposed to mean, as the formulae I've seen in the papers cannot be found in any standard book or reference. Please let me know if ...
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93 views

Compute Thrust from RPM and Induced Velocity

I'm attempting to calculate the difference in thrust in a secondary propeller operating in the wake behind a primary propeller, in the context of a trailing quad-copter following a leading quad-copter ...
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66 views

How to compute actuator torque requirement for Variable pitch mechanism??

Suggest me any reference to compute the torque requirement for actuator/motor to control the pitch angle of propeller (Variable Pitch Propeller). Thanks in advance Arun Ravindran
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126 views

How does a partially covered air intake affect the thrust of a propeller ?

does a partially covered air intake of a ducted propeller significantly affect its thrust? If so, will it be like 10 or rather 90 percent less thrust ? Thanks for your answers! Simon
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312 views

What causes these losses in this propeller simulation?

While running a CFD simulation comparison of 2 vs 3 blade propeller versions (48" diameter, 23" pitch, 3570RPM), I've come up with: 2-blade: 347N of static thrust @ 110Nm Torque 3-blade: 220N of ...
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829 views

why are airplane propellers always undersized?

While calculating propeller static thrust by using a famous Prop-power-calculator.xls (by Pé Reivers), I've noticed that no matter what "stock" configuration I put into the calculator, I do always get ...
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242 views

What is the history of this specific Cessna propeller (s/n F2430)?

Hoping someone can help... I'm looking to get some information about a Cessna plane propeller my Fiancé recently bought. It's his birthday coming up and it would be great to have any sort of history, ...
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28 views

Comparison of specific thrust vs. speed, for EDFs and propellers

I stumbled upon this graph showing the decrease in specific thrust (Thrust by Power) in relation to velocity, for a Schuebeler EDF: https://www.researchgate.net/figure/Specific-thrust-T-P-vs-airspeed-...
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1answer
140 views

Why does a force on a propeller act 90° “ahead” due to gyroscopic precession?

This is a common explanation: A tailwheel airplane is on the takeoff roll and the tail comes up, the propeller disc rotates forward. That's akin to someone pushing on the top of the disc. The force ...
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1answer
72 views

How to do blade element momentum theory analysis for different geometries of airfoil, e.g. NACA airfoils?

I want to analyse NACA airfoils using BEMT. I have only yet done it for basic symmetric airfoils. I would like to know what all assumptions remain same in NACA airfoil analysis and to what degree it ...
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118 views

Would large, low aspect ratio fan/propeller blades be more efficient? Why not?

With reference to this answer We read in the above that accelerating a larger mass of air by a smaller amount is (theoretically) more efficient. This is an advantage of a larger propeller than is ...
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57 views

Why does a shrouded propeller have a lower downstream velocity than an unshouded propeller?

Why does a shrouded propeller have downstream velocity $V_3 = V_0 + w$, while the unshrouded propeller has a velocity $V_3 = V_0 + 2 w$? What are the reasons of this difference? $ \begin{align} w &...
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262 views

What factors determine magnitude and orientation of induced velocity at propeller blade?

• Magnitude What factors determine magnitude of "Vind" (induced velocity)? • Orientation If we take analogy with induced velocity at wing,isnt "Vind" must be prependicular to Vr? • ...
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In actuator disk theory, why does changing the inertial reference frame work for Bernoulli's equation?

I was reading this website: https://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node86.html, which goes over actuator disk theory, and it discusses using Bernoulli's equation in a frame of ...
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83 views

What is the effect of moving a propeller closer to a wing?

Does it improve efficiency? What if the wing is just a plate? Certainly increasing plate thickness will decrease efficiency.
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183 views

What is a good and simple software for calculating propeller thrust and required power?

My main requirements: Calculate propeller thrust with big range of the altitudes (0 - 200 km) or to have air pressure input parameter, which I can type. For example pressure for 152 km is $4.98\...
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63 views

What kind of propellers are generally mounted on the Aeriane Sirocco?

I'm curious what propeller is used for the Aeriana Sirocco. Online I see lots of pictures of propellers with three blades, but none with only two and I cannot find many clear pictures of the proppeler....
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141 views

flow rate through a propeller disc

Let's take the case of a stock Cessna 150, chained to the ground, standard day conditions. The engine is running at full power (say 2500RPM) and the propeller is absorbing its full output. Is there a ...
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167 views

Propeller air displacement

I was thinking about propeller design just now and it came to mind that, theoretically, the air displaced by the propeller after every rotation might not be able to "flow back" into the area "served" ...
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144 views

Fly a fixed wing single propeller airplane like a helicopter?

Has anyone tried to "helicopter" an airplane? And succeeded? And posted this video on the internet where I can find it? What I'm talking about with what I would call a "helicopter&...