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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XRotor blade angle distribution
My question is about the XRotor definition of the blade angle distribution (beta), which XRotor solves for or requires as input. Is the blade angle on XRotor defined as the angle between the rotation ...
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Did WW2-era aircraft have constant-speed or variable-pitch props?
This is slightly related to my other question on variable-pitch controls.
I want to know if WW2-era aircraft typically had variable-pitch or constant-speed propellers. Variable-pitch lets the pilot ...
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Do full-feathering constant-speed propellers have a high-pitch stop for the prop governor?
On full-feathering (hydraulic) constant speed propellers in general, and specifically Hartzell and McCauley props, does the propeller governor have a high-pitch stop (like non-feathering propellers, ...
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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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Why are push-propellers so rare, yet they are still around?
Jet engines are by their very nature push-engines, however, most propeller airplanes use pull-engines. Is there an inherent advantage to using pull-propellers except for the increased airflow over the ...
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Should I advance my propeller lever forward during a glide?
I am reading the FAA Airplane Flying Handbook, chapter 3. It says:
To enter a glide, the pilot should close the throttle and, if equipped, advance the propeller lever forward. (...)
Why do we ...
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Cause of Drag From Windmilling
I know that when a propeller is windmilling it creates drag, I assume this is from the propeller being flat against the air causes drag, but propellers are designed to essentially pull an airplane ...
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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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What would have been the pitch angle of this McCauley Prop before impact?
I'm trying to determine the pre-impact pitch of a two blade McCauley variable pitch on a Cessna 210 that hit shallow ocean water (8 feet, mostly sand) shortly after takeoff from an altitude of 300 ...
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Can a propeller with 90° pitching and symmetrical airfoils generate thrust?
Imagine we have a plane that is already moving at a speed $v_{plane}$. At a certain time $t=0$, a motor starts moving a propeller whose blades consist on symmetrical airfoils with $90^\circ$ of ...
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Actual non-axial airflow (sideslip) for a propeller driven aircraft
I am making a propeller model for a two-engine propeller driven aircraft (like a Dornier 228). I have expanded my model to include the non-axial airflow as well. $$ $$
By non axial airflow, I mean ...
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What are the advantages of more than 4 propeller blades?
I have heard that propellers with more than four blades are not as efficient as 4 or less blades because of lower thrust which may result from interfering prop-streams. But I see the ATR-42/72 and ...
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What types of wood can be used for making propellers?
Early propellers were made from wood and they still are on some vintage/classic aircraft and reproductions. What types of wood are typically used to make wooden propellers?
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How do I compute thrust of a rotor disk and the necessary power to drive it??
as it seems, this question has been asked a few times here so please forgive me for asking again.
If I have 50 BHP shaft power available at 5000 RPM and 106 N.m torque, then can I convert it to 200 ...
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Does the obstruction in a propeller duct increase exhaust pressure or decrease pressure/increase speed?
I came up with this question when looking through the answer for this question, which states that a convergent duct(obstruction) compresses the exhaust so that its pressure matches the ambient ...
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Can you weld a propeller blade from 120 degrees to 180?
My uncle flew for Mission Aviation Fellowship (maf.org) for a university in Texas, and I believe that he was flying a Cessna to the Amazon (among other places). He actually knew Jim Elliot (who went ...
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Are there any variable-diameter propellers?
Have there been any known tests or prototypes of variable-diameter propellers?
There's this paywalled paper from 2014 that seems to have made a virtual prototype model, have there been any physical ...
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Could floppy rotor blades be usable?
Autogyro and helicopter blades are more or less flexible, and when not stiffened by centrifugal force they droop noticeably. A extreme case would be that of fabric blades. They have been used at least ...
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Do ducted fans have a future in forward flight aircraft? Can they be made more efficient than open rotors?
I'm fascinated by how ducted fans have the ability to be more efficient than open propellers of equal diameter in vertical flight through the use of tight tolerances, lightweight duct material, proper ...
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What is this indication on most turboprops?
What is the small fan I've seen on different turboprops?
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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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Does a windmilling propeller create more drag than a stopped propeller in an engine out scenario?
For this question lets assume that we are talking about a fixed pitch propeller and not a variable pitch propeller. I do understand that variable pitch props should be feathered during an engine ...
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How high can propeller airplanes fly?
Is there a maximum height a propeller airplane could fly?
Some lower bounds for maximum flying altitude:
12,000m (39,370ft): Antonow An-70, produced 1994
12,310m (40,387ft): Lockheed Martin C-130J ...
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Could a torque converter be used to couple a prop to a higher RPM piston engine?
Every RPM reduction gearbox I look at seems to have more parts in it than a Swiss watch. Great for keeping time but many parts to wear and breakdown.
What seems especially worrisome is the direct ...
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Is it OK to move a light aircraft by pushing or pulling the propeller?
It's very common to see pilots moving a light aircraft by pushing or pulling on the prop, either because there's no tow bar available or simply out of preference or convenience. Is this a reasonable ...
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Why would the tip of a propeller stall if geometric pitch was the same throughout the length of the propeller?
I can't seem to understand this sentence from the FAA PHAK about why propellers are "twisted."
"If the blades had the same geometric pitch throughout their lengths, at cruise speed the ...
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How to know what kinds of airfoil being used in a commercial propeller?
Suppose we know the 3D CAD model of a commercial propeller. Starting from that, we do the slicing to get the profile of airfoil being used to generate the complete shape of the propeller. How do we ...
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Why are aircraft piston engines are so low rpm lazy engines?
I understand that the propeller speed should not be too much otherwise it will stall at the tip and be useless so higher rpm engine would be useless when we first think about it. However, we can put a ...
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Stall on low airspeed with high power on right-turning propeller
Q: The pilot of an aeroplane with a single engine and right-turning propeller (clockwise from the pilot’s viewpoint) decides to go around. The pilot raises the nose too much as the power increases and ...
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Torque and engine torque after aplying prandtl tip loss factor
I have a question regards to the following formula related to Blade Element Momentum theory for the application to calculate on airplane propellers:
$$ dQ=4\pi r^3 \rho V_\infty(1+a) a' \Omega F dr ...
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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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Are ducted fans more efficient?
As far as static thrust, does a shrouded/ducted propeller outperform an un-shrouded propeller? It seems that the guide blades on the bottom of the duct would allow little more thrust to be extracted ...
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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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What would happen if the blades of a variable pitch prop did not all have the same pitch?
What would happen if one or more of the blades (but not all) on a variable pitch prop would not tilt at the same angle as the other ones?
Could this situation happen or is the technology so advanced ...
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Pusher vs Pull prop [duplicate]
Probably a pretty simple question, but what exactly are the pros and cons of pull and push propellers, and is there a reason why pull propellers are a lot more prevalent in planes than pusher ones?
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How does propeller length, pitch, and airspeed affect efficiency? [closed]
tl;dr: trying to find propeller efficiency with thrust, velocity and power and see which propeller length to pitch ratio is efficient.
Hello, I'm a high school student working on an extended essay for ...
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What is the nature of feathering in an ATR type aircraft?
If the engines fail for some reason midflight, does the ATR aircraft automatically feather the affected engine? In rare cases if both engines fail, does the automatic feathering happen for both ...
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What happened to the blades in this picture?
Here is the picture
Source:(brians-travels.com)
This looks like a photoshopped picture, but I believe it isn't. Is this some kind of strange occurrence that occurs only with the human eye? The ...
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For an electric airplane are propellers the only option for propulsion?
This is for an electric airplane (so no fuels for combustion):
Are propellers the only option?
Is there a turbine-jet possible with only air intake, electrically compress, and a turbine and nozzle ...
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Centrifugal force created by a 1045 propeller
I currently am creating a project in which I'm using a 1045 propeller with a BLDC motor that spins at ~16,000RPM. It is powering a single motor "rocket" that basically is configured to carry ...
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P Factor vs Spiral Slipstream
Does anyone know of any real aeroplane or wind-tunnel tests that quantifies the effects of asymmetric propeller blade loading (P factor) versus the Spiralling Slipstream effect in creating yaw.
Which ...
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Is my equation for calculating ducted propeller thrust correct?
The equation is 13(EfficiencyxProp diameterxoutlet diameter)^2/3
It seems really high when I use inches and really low when I use feet.
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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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What is the aerodynamic influence of prop spacing and placement in multi-prop engine setups
I saw this question Is there a rule of thumb for spacing between jet engines?, which referred to How do you choose engine placement for under wings engines?, but I was wondering how the engine spacing ...
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If the pitch of a bypass fan blade in a turbofan is fixed how does it manage to provide thrust over such a large speed range?
A fixed pitch propeller is only good for aircraft that do around 100kts because the angle of attack on the propeller decreases as the forward airspeed of the aircraft increases, limiting the thrust ...
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Estimating piston-engine thrust on take-off
In my Uni course I've learnt how a piston-engine produces a constant power, as opposed to a constant thrust like in a jet engine, which can be estimated as Thrust = Power / Velocity. However, using ...
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Would the dle 55ra engine be enough to power my paramotor(ducted fan)?
I plan on using the dle 55ra engine to produce 5hp at 8,500 rpm. I am using it in a paramotor, and to save space I am considering using a ducted propeller similar to the Fulcrum power pod. The duct ...
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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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How did the propellers on the B-29 stop perfectly in sync?
In the photos below, the propellers on the B-29 props all stop in the same position. Is this done by hand, it is this automatic?
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How to calculate lift/thrust effect of adding blade to a propeller?
Source:
Say I have blades of a propeller of an aircraft (airplane or helicopter). The blades have exactly the same profile, size, dimension, and weight, and will be coupled to a shaft with the same ...
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