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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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Can an ultralight aircraft fly with a 18hp engine?

I have some questions - I'm planning on building single seat UL aircraft with this plan sketch (I have more), I drew this based on real plain and some research. Empty weight is between 50-70kg with ...
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1answer
343 views

Why use jet engines instead of propellers when designing new airplanes?

I'm looking at the 100 people project and I am looking at clean airplanes. Why did we stop using a clean source of lift, the propeller?
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2answers
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Does contra-rotating vs regular propellers, have any effect on icing?

I am trying to understand whether can there be any correlation between the contra-rotating propellers and the ice accretion over the wing ? For instance, is there any evidence that ice accretion is ...
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Ducted Fan vs Open Propeller Efficiency [duplicate]

If we are talking about a slow flying aircraft with subsonic propeller tips, will adding a shroud increase efficiency, all else being the same?(ignoring the friction drag)
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1answer
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How does a fixed-pitch propeller changes the blade's angle of attack?

Studying I have found a question that states that in a fixed-pitch propeller in flight at a given TAS, the blade's angle of attack will change if RPM increase, but I don't understand how can the blade'...
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1answer
548 views

In a piston aircraft, how much noise is generated by the engine, and how much by the propeller?

I've been reading quite a few articles lately about how noise complaints from GA airports across the country. One of the common suggestions to fix the issue is to simply use an electric engine ...
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131 views

How was the rotation direction decided for single engine propeller craft? [duplicate]

Spitfire, FW-190, Ki-43... was it selected arbitrarily to spin counter-clockwise?
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0answers
237 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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1answer
447 views

Can I model propellers used in electric aircraft the same way as I model RC quadcopter drones?

I am writing an article about mathematically modelling a flying car, using D'Alembert's principle. I need some information about the propellers ... When I worked with the mathematical model of a small ...
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2answers
1k views

How to design the blade twist angle in propeller design?

I am designing a scale propeller for small UAVs and I have computed blade twist distribution for the blade airfoil sections. While I was modelling the propeller I have set the angles to twist about ...
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2answers
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What do I need to know to design contra rotating propellers for a powered paraglider?

I wonder if anyone has any technical information that would assist in using the correct Size & Pitch Contra rotating Propellers (CRP) on this Foot launched Powered Paraglider engine ? We are ...
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3answers
439 views

Do propellers generate static electricity in flight and how is that handled?

How is the risk of tribocharging (static electricity generation) by the propeller managed on an airplane? Regardless of airplane size, it seems the rotation of the propeller or engine blades could ...
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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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3answers
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What's the use of so much torque on propellers?

(This question is closely related to this question) A typical Cessna 172 has a 180 hp engine, with a max. rotational velocity of 2700 RPM. Even small 1 hp electrical motors can achieve that RPM, and ...
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1answer
369 views

What is the typical blade pitch angle of a ram air turbine?

I'm building a simple 3d model of one and because reasons I won't be able to give it a variable blade pitch so I need to find a typical value. My google-fu has failed me so far on this.
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3answers
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In a constant speed propeller, why does the RPM drop with a prop pitch increase?

When a constant speed propeller changes its pitch from low to high, RPM would decrease. Why is that the case? Wouldn't the RPM increase when we increase the blade angle since there's less drag and ...
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1answer
511 views

Why are 4 blade propellers often in X or + position when the aircraft is parked?

Is there a meaning to the position of 4 blade propellers on parked warbirds? A lot of old pictures have them at X or + positions.
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1answer
276 views

How to find trim condition of a sectional airfoil without knowing the angle of attack?

I am using a reflexed airfoil designed for positive pitching moments to achieve a pitching angle matched to the changing of free-stream velocity (Aerodynamically tailored). I ended up with a pitching ...
3
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1answer
573 views

What is this three-bladed vintage aircraft?

We found this poster at IKEA, EDELVIK Poster 103.776.29. Allposters.com has another poster, which includes the same aircraft, but 2 in formation, possibly the same original photo/artist?
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1answer
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How to calculate variable pitch propeller parameters?

I'm carrying out a project on Variable Pitch Propellers for UAVs and especially self-adjusting or Passive Variable Pitch Propellers that change pitch due to aerodynamic forces and Pitching Moments. ...
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4answers
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What are the reasons behind this pusher propeller configuration?

Can a pusher configuration sort of like this have its propeller close to the tail (if it were one of those split tails like on a A-10)? Why did they put the propeller above the cabin and not in ...
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2answers
1k views

Can drone with two propellers above one another fly vertically upward without spinning? [duplicate]

Basically, like the propellers setup in this image without the tail end bit: Where the propellers will be spinning in opposite directions. This would, in theory, counteract the angular momentum to a ...
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3answers
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Why doesn't the plane accelerate/move forward when it's at rest, if the propeller is spinning?

I'm having difficulty seeing the difference between a stationary plane and a moving one. When you start the engine in the C172, the blades on the prop are spinning - but the plane doesn't move at all....
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0answers
573 views

Shaftless propeller vs duct fan [duplicate]

If both have the same dimension, same amount of fan blade, and supplied by the same amount of energy, which one would product bigger thrust and less total drag (the drag on the blade and the "tube" ...
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2answers
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Why do propellers on aircraft have a slight offset angle?

Single-engine aircraft (one propeller on the 'nose') Why do propellers on aircraft have a slight offset angle? I have picked up this information that the rotational axis of the propeller is not ...
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0answers
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Why are there curved propellers? [duplicate]

Why are there curved propellers on some aircraft, what is there advantage? If these are worthwhile advantages why aren't there curved blades on turbo fans?
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3answers
675 views

Why is the available power in propeller engine is almost constant for every velocity?

I surfed on the internet for an answer but I didn't find any. I'm taking Aircraft Performance course. I saw that available power for propeller engine is almost constant for every velocity. But I don'...
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2answers
478 views

Are there any ducted propeller or fans without a shaft in the centre?

Are there any propeller or fan designs that hold the propeller or fan in the duct and do not have a boss or propeller shaft? This could reduce the drag of the centre. Are there any other advantages?
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1answer
173 views

Aerodynamics of a Propeller [duplicate]

I'm having troubling understanding where the relative wind is coming from for a propeller. The relative wind that I do know is the one that comes right in front of the aircraft which flows over the ...
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1answer
4k views

How much lift must a helicopter rotor produce?

How much lift must a typical helicopter rotor produce? For example, consider the rotor of what seems to be a common helicopter: the Robinson R22. Is the lift produced equal to one of the following: ...
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1answer
1k views

How much thrust is gained from placing a propeller in a duct?

Assuming that the power and diameter are the same, how much extra thrust can be gained by placing a propeller in a duct? How does it influence the RPM? To clarify: take any prop, place it in a well-...
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2answers
3k views

How does blade solidity ratio relate to thrust/power/torque of a propeller?

for quite some time I was using ABBOTT formula for static thrust estimation on a two-bladed propellers: $$ T=6.8\times10^{-5}\times D^{3}\times p\times RPM^{2} $$ $T$ is Static Thrust (N); $D$ is ...
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1answer
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Where can I find info or techniques on calculating the influence of a duct on the thrust and efficiency of a propeller?

I am trying to run numbers on a concept VTOL fixed-wing aircraft, and I am looking at having fans or props positioned inside the wings, (which would therefore make the wings relatively thick for a ...
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2answers
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Why does this analysis show very high stress in a propeller?

I have been trying to evaluate the stress on aluminium propeller: Diameter: 78", 2600RPM Have fed load numbers from here, applied distributed mass model onto the blades. ...
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1answer
713 views

What is the optimum separation between contra-rotating propellers?

What is the optimum separation between contra-rotating propellers? What factors determine the distance between the two sets of propellers?
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2answers
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Why is max endurance different for jet and props?

Max endurance speed is not the same for gliders, propeller planes (also for turbo prop, right?) and jet planes. While for for jet planes max endurance is at the minimum drag speed ($V_{md}$), for ...
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2answers
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What is this odd aircraft?

What is this aircraft? It was parked at transient parking at the Southern California Logistics Airport. It is a pusher prop driven plane with a conventional tail. High aspect ratio un-swept wings. ...
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0answers
168 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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6answers
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Why don't drones use ducted fans?

If efficiency of converting battery power to lift or thrust is paramount, why don't drones use shrouded or ducted fans, instead of unshrouded propellers? This is the only image I could find to ...
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1answer
342 views

Do all the engines/propellers of a VTOL UAV need to be identical?

I would like to know if VTOL UAVs necessarily need $n$ identical propellers and motors. Have any design solutions considered the possibility of using non identical props? For instance 2 motors of type ...
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4answers
477 views

Which 'pusher' propeller aircraft have been used in active military service?

The only 'pusher' aircraft I know of that has been used in active military service is the SAAB 21. There are several prototypes out there, but I can't see that any others were used. Which, if any, ...
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0answers
285 views

What contra-rotating propellers would be appropriate for this engine?

I am currently getting an X4 cylinder, 150cc, 4 stroke engine 3D CAD Modelled, this engine is initially being designed for Powered Paragliding (PPG), classified as experimental Aircraft, so no ...
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1answer
551 views

Do low-cost airlines make more profit than luxury airlines? [closed]

I was watching this TV show and it said that currently low-cost airlines e.g. Ryanair/Easyjet make more cumulative profits than more expensive long haul airlines such as British Airways and Virgin ...
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1answer
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What are some of the largest propellers post-WWII?

(Source) The propeller on the Linke-Hofmann R.II (1919) holds the record at 6.9 m (22 ft 6 in). What are some of the largest propellers post-WWII? Top 5 or so.
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3answers
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What is the difference between a propeller and a rotor?

I have been making the mistake of using words "propeller" and "rotor" interchangeably when they are not the same thing. What is the difference between a propeller and a rotor?
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3answers
3k views

Why are the top speeds for jet engines higher than for propellers?

I realize turbines are more efficient than piston engines, but if that were true, then why don't turbo-props reach jet speeds?
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2answers
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At what point is a turbine powered ducted propeller considered a turbofan?

Turboprop Propellers can be ducted for extra thrust. What are the criteria for determining that the engine is no longer a ducted propeller design, but a turbofan? Does there have to be a type of ...
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1answer
2k views

Why don't contra-rotating propeller configurations with more than two propellers exist?

I wasn't able to find a single example of more than two propellers stacked axially in a contra-rotating configuration. There is a huge number of contra-rotating propeller setups, but it is always a ...
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1answer
754 views

What is the force to change the pitch of a variable pitch propeller?

At the moment I am struggling with the problem that I do have an idea how to calculate this force by using the blade element theory and going over a whole propeller blade in order to calculate the ...
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1answer
641 views

Do propeller coefficients go to zero at the same value of advance ratio?

Graphs of power coefficient ($C_P$), thrust coefficient ($C_T$), and efficiency ($\eta=JC_T/C_P$) of the 5868-R6 propeller as functions of advance ratio ($J=V/(nD)$) and propeller pitch (blade angle ...