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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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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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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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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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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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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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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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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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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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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Is there any equation to bind velocity, thrust and power?
I am designing a remote controlled airship. I will tune it so that the lift given by Archimedes' Principle will exactly balance the weight of all the structure. It will be propelled by brushless ...
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where is the centrifugal force the flyweights experience coming from?
The T6b uses a PT6-68 engine which has a variable pitch, constant speed, feather, and non-reversible prop system. There is only one lever in the cockpit which regulates Torque and the Power Management ...
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Is an aileron roll easier, opposite the rotation of the propeller?
We all know helicopters have tail rotors because they would spin out of control thanks to Newton's third law.
That got me thinking, would a single propeller plane have an easier time doing an aileron ...
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Has the use of a radiator surface on the inside of duct ever been tried?
I wonder if using radiating surface on the inside of a ducted fan to dispel the waste heat of an engine would provide an economic advantage by increasing thrust? Since a typical engine “wastes” some ...
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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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Jumo 222 What are the design choices that lead to this particular nose cone and spinning cowling setup?
Looking for Jumo 222 powered aircraft, I came across this picture of a Junker Ju 288, with this strange spinning cowling and propeller setup, what are the considerations behind this design, how does ...
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How to design a propeller for UAV?
I need some advice on designing a propeller for a UAV and choosing the right motor for it. I am doing a project which requires the fix-wing UAV to travel at cruise speed of 20 m/s and weighs a total ...
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Is it a better idea to put propellers on the wings than the nose?
Most propeller aircraft have either a single propeller at the nose or two propellers on the wings. Nose propellers have a big disadvantage as the big fuselage can obstruct the airflow of the propeller ...
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What are these points in the Propeller Schematic?
If it matters, this is taken from EASA PPL questions.
The graphic appears to be taken from the side point of view, although I've never seen such a round Spinner, unless it's a variable pitch propeller ...
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Would a coaxial propeller with the second prop slower and larger improve speed?
Looking at various propeller designs, I started wondering about these limitations:
Large propellers at high speeds have tips going supersonic
Scimitar props attempt to keep prop tip from going ...
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Would it be beneficial to have rotors AND propellers instead of a tiltrotor?
Would it be beneficial for tiltrotor aircraft if they had BOTH rotors and propellers, instead of the hybrid proprotors that are neither good propellers nor good rotors?
Like imagine the V-22 Osprey ...
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Do constant speed propellers actually increase fuel efficiency?
I have a few questions regarding constant speed props. As a pilot who just recently moved up to aircraft equipped with constant speed props (Cessna 182, Piper Dakota), I understand that a constant ...
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Could ducted propellers improve efficiency in small drones?
I have seen that a new electric airplane design has decided to a choose ducted propeller design somewhat similar to the one of jet engines, explaining this design choice with the fact the ducted ...
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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 ...
