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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Hypothesis: swept back propeller would reduce drag and increase thrust [duplicate]
Hypothesis: swept back propeller would reduce drag and increase thrust. Any experience with this?
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Deriving Accurate Exit air velocity of rotor
My goal is to derive the equation for exit air velocity as a function of:
Pitch angle
RPM
Rotor Radius
Constants like ρ
Assumptions:
Vc is relative velocity of air upstream, and is = 0
Inflow is ...
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Can an airplane propeller become supersonic?
Is it possible for an aircraft propeller to become supersonic?
I am not referring as for the aircraft, only the rotating blade.
I know it is extremely unlikely for a propeller plane to go supersonic, ...
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How many ways/methods to calculate propeller/rotor's power output? Which one is the best?
Source: Wikipedia
I want to know how many ways/methods to calculate the output power of a propeller? So far I knew three methods:
Momentum Theory (MT),
Blade Element Theory (BET),
Blade Element ...
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What velocity is used to calculate maximum range and maximum endurance?
These are my data;
$C_{L_0} = 0.4$
$C_{L_{\alpha}} = 5.7$
$C_{L_{minD}} = 0.14$
$C_{D_{min}} = 0.022$
$k = 0.035$
$\alpha_{stall} = 15$
$S_{ref} = 20m^2$
Mass Data
$W_{total} = 2500 \text{ kg}$
$W_{...
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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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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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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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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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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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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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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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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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What is this indication on most turboprops?
What is the small fan I've seen on different turboprops?
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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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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Why have supercritical airfoils not been used in designing the propeller blades?
In terms of specific fuel consumption, propellers are more economic than jet engines at low speeds (<0.5 Mach) but at high speeds, the propeller blade tip reaches locally to supersonic speeds which ...
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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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What's the reason of engine roughness while leveling off from climb or recovering from stall?
I want to find out that if relative wind pressure can affect engine or not.
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Variable-pitch propeller blade design (AOA)
For a variable pitch propeller where the angle of attack can be adjusted during flight, are the individual blades similar in design to standard propellers, with a low angle of attack at the edge of ...
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What is the range of ratios between optimal propeller efficiency and true propeller efficiency?
In https://aviation.stackexchange.com/a/15383/20394, the optimal prop efficiency is given as:
$$\eta^{opt}_{Prop} = \frac{1 - \frac{\Delta v\cdot \left({v_{\infty} + \frac{\Delta v}{2}}\right)}{d_P^2\...
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static thrust vs. prop RPM data?
edit: question was too long, and is actually simple, so I removed unneccesary description
Background:
There are many questions here about:
propeller efficiency
changes to thrust when it is dynamic
...
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When using momentum theory for estimating power needed to hover, is propulsive efficiency accounted for?
I am using momentum theory to estimate power needed for an eVTOL. I have read past papers where the results got from momentum theory was direcly use to estimate the power needed from the battery. How ...
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Why the greater the propeller slip is, the more thrust it generates?
Forgive my poor English skill and my entry-level understanding of aviation stuffs. I'm currently a student pilot.
As I understood, the propeller slip kind of represents the propeller efficiency in ...
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How reliable are the available airfoil data sources?
I am making calculations based on Blade Element (Momentum) theory (BEM) for propellers and I am trying to find the angle of attack at which the propeller performs most efficiently.
If I have ...
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