Questions tagged [thrust]
Questions about the propulsive force of a powered aircraft.
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Where is the thrust of a turbojet felt? [duplicate]
At a high level, this is simple. Hot gas goes out the back, and Newton's third law says the engine is pushed forwards. But when you look inside the engine, it's less clear which part experiences the ...
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How to determine thrust and power requirements from take-off ground roll distance?
I'm working on a project which requires me to determine the power requirements of a propulsion system from a specific take-off distance. Starting with this equation:
$$
s_g\approx \frac{1.21(W/S)}{...
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How does a fan in a turbofan engine suck air in?
I watched lots of video related to sucking process of a fan in a turbofan engine, but I'm confused at a point.
In this link and many videos like this, I found the fan'...
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Helicopter total power required: zero wind speed while climbing --vs-- down wind speed while hovering
I've been stumped on this for a while. Let's say you have a helicopter in climb mode (i.e., 100 ft/min) with zero wind speed present. Would the total power requirement be the same as if the helicopter ...
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How can I calculate the thrust of a propeller?
I am working on designing a paramotor, and need to calculate estimated thrust for the propeller. Is there a calculator or equation where I can input a diameter, pitch and rpm and get a ballpark thrust ...
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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 much horsepower do I need for my paramotor?
Assuming my full kit and I weigh 82kg total, I have estimated that I need 5hp. To calculate this, I used the formula:
weight force (W) is F = m g
W= 82kg*9.8 ms/2 =401.8 Newtons
Now, if the drag ratio ...
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How much thrust should be applied when you set the autopilot to a specific altitude?
After a plane takes off the pilot usually sets the autopilot to the altitude of the flight level they are about to cruise at, e.g. 30,000 ft, right? When that is the case, how much thrust should be ...
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how does the lilium jet counter asymmetric thrust?
So Lilium states that its jet is a tailless design. Now, you can see that it has engines on both sides of the centerline.
Lets imagine that all of the engines on one side fail, how does it counter ...
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How can I calculate the TOTAL drag of the ENTIRE airplane?
I have an aircraft similar to a Cessna 172 and am using a virtual wind tunnel software (flowdesign) to get a drag estimate. I import the airplanes 3D model and I get around 2240 lbs of drag with a ...
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How do airplanes with thrust lines above CG still fly without a down pitch moment?
Mainly the Icon A5. I remember trying to make an RC aircraft similar to it, but the moment i'd spin up the motors the aircraft would understandably pitch down. i couldnt fly it at all.
So how do these ...
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What is the general mathematical relationship between increasing an airplane's weight and the needed thrust to fly?
I understand that increasing an aircraft's weight without changing any other properties means that its takeoff, stall and cruising speeds all increase since you need to generate additional lift. So ...
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How much thrust can a balloon generate with wings?
I have heard that some balloons have been made with wings, angled such that they generate some forward thrust during the ascent. Balloons can also theoretically generate thrust with wings during a ...
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How can a turbofan's fan generate thrust in cruising flight if air is being slowed down?
High bypass turbofans in airliners generate most of their thrust from their fans, not their "cores". However, at cruise they are actually spilling some air past the intake rather than ...
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What is the thrust to weight ratio of the A330-900neo?
Does anyone know what the thrust-to-weight ratio is for the Airbus A330-900neo?
I'm getting different numbers when I try to calculate this for myself.
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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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Why is the Cirrus Vision SF50's turbine angle so acute?
I saw a Cirrus Jet on the ramp and was struck by how much its engine points upwards. I can't recall having seen this kind of positive thrust angle, and so wondered what the explanation was.
A picture ...
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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 is bleed air flow related to thrust level?
I read that the bleed flow negatively affects the thrust levels for a turbofan engine. However, I was wondering if vice-versa is true as well? Whenever the thrust levels for a turbofan are lowered at ...
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Power calculation of propeller
This is probably a very simple question, but I have been really struggling and need your help.
I have simulated a propeller with these parameters on Ansys:
Thrust: 2000 N
Angular Velocity: 314 rad/s
...
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Why do turboprops not have a thrust value in the specifications? [duplicate]
When looking through aircraft engine specifications, turbofans always provide a thrust value, e.g. in JT8D engine: https://prattwhitney.com/products-and-services/products/commercial-engines/jt8d
In ...
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Why is thrust (in a high bypass turbofan for e.g.) non-linear with respect to N1?
I've been studying jet engines for a short while now and I think I have a pretty decent understanding of how thrust is generated, but one thing I'm struggling a bit with is how thrust varies across ...
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What is meant by the pointing vector and pointing vector magnitude in ECI?
In Siouris's Missile Guidance and Control Systems, it is stated that the angle of attack can be approximated in a 3DoF (degrees of freedom) simulation by the following equation:
I know that ECI ...
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Why do pilots slowly give the plane more thrust during takeoff?
I have mostly seen pilots slowly pushing the throttle to toga during takeoff. But why? Why don't they just directly put the throttle to toga? Wouldn't that save runway length?
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What is the maximum Mach number that can be achieved at the exit of CD nozzle?
I understand that you can get Mach 1 at the throat of a convergent-divergent (CD) nozzle and after that you can have two roots, one is for subsonic and other is for supersonic.
Considering the ...
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What do you call a fall that is due to too little engine power, not due to cessation of aerodynamic lift?
If you raise your plane's pitch but the engines can no longer counter the gravity and you begin to fall (because the engines are too weak, not because of too little lift), what do you call that? This ...
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Is axial bearing in turbo fan,turbo jet engines neutraly loaded?
Is axial bearing in turbo fan,turbo jet engines neutraly loaded,if yes then turbine/fan and compresor produce eqaul and opposite force?
If yes ,where then thrust come from,at internal walls,must be ...
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What exactly is the pressure thrust component and why does it exist?
I'm teaching PowerPlants on a ATPL theory course and honestly have some trouble wrapping my head around this one:
Most literature describes the term "pressure thrust" – as opposed to "...
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Using a spring balance to find static EDF Thrust
I have been attempting to measure the static thrust of my EDF with a spring balance. It is part of a group university project. The EDF specs are as follows: 90mm freewing 9 blade 1900 Kv thats rated ...
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Why is thrust inverse to speed in piston engines?
It is said that piston engines have constant power output, and thus their thrust is inverse to speed (e.g. here), while turbines have relatively constant thrust. I'm looking for an intuitive ...
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How to calculate the efficiency of a rubber powered propeller
I made a simple test rig together with a stopwatch to measure the thrust (in grams) with respect to time of a rubber powered propeller. This enabled me to compare the performance of different ...
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What is the specific fuel consumption and cruise thrust of PW1521G engines?
I'm looking for the specific fuel consumption (SFC) and thrust related to PW1521G in cruise regime, as well as the associated assumptions for these ratings. I can't find them online.
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Electric ducted fan with thrust tube thrust and exit velocity calculation
I am working on an electric ducted fan rocket that has thrust vector control, see image 1. The 90mm EDF is located a bit higher above this blue section, near 1., so I believe the blue section becomes ...
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Is thrust larger than weight in a vertical climb?
Image source
Very much related to the many questions and great answers to lift and weight in a climb - if an F-16 climbs vertically at a constant speed, is thrust greater than weight?
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Calculating the Thrust vs RPM Relationship of a Brushless DC Motor
hope everyone is doing okay.
I am conducting a project with my friends for an Unmanned Aerial Vehicle. We are first using MATLAB - Simulink to design and simulate the quadrotor. We completed the ...
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Other than fighters, which airplanes can fly straight up?
I would think, for example, all modern fighter jets can maintain 90 degree climbs due to having thrust to weight ratio greater than one.
Are there any other air planes which can do that?
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Can a stopway withstand thrust of B737 engines on takeoff if the aircraft is lined up on the edge of the runway?
Can the thrust of Boeing 737-300 engines break the asphalt surface of a stopway marked with yellow chevrons? Can anyone give a documented reference?
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What is the approximate thrust at sea level for a C-130J Hercules?
I am looking for the approximate thrust of a C-130J Hercules under ISA sea level conditions. Also the efficiency of its propeller would be of help.
An answer to this question would really help my ...
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On a Boeing 737, can the APU, BY ITSELF, provide enough thrust to move the plane while on the ground? [duplicate]
There are numerous questions and answers about the ability of an APU to provide enough thrust to maintain flight. In contrast, my question is whether the APU, by itself, provides enough thrust to ...
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What thrust is used for thrust to weight ratio?
Performing some preliminary calculations for an aircraft design I have and was wondering what thrust I should use to calculate thrust to weight? The thrust calculations I have, vary due to speed (...
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Relation between lift force and torque produced in propeller used for vertical take-off and landing aircrafts
There are many answers for this question but none of them are specific.
I need to find the exact relation between the lift force of a propeller of specific pitch, attack angle , dimensions and ...
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What should be the thrust weight ratio for takeoff? [closed]
I am doing some calculations for preliminary design of an airplane and I was wondering how I would go about determining the minimum thrust to weight ratio needed for the aircraft to takeoff. Which ...
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Why is TOGA thrust 'never' 100% N1?
The title is voluntarily the opposite of this question: Why isn´t TOGA thrust always 100% N1 or N2?.
I explain to you with an example: I'm looking to the FCOM of an A320 which states that the "...
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What is the difference between RTOP, MTOP, and MCP?
I am currently learning how to fly the SD3-60 (Shorts) Aircraft, and I am trying to gain an understanding of RTOP (reserved take off power), MTOP (max take off power), and MCP (max continuous power). ...
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Why do we take off with maximum power settings?
In most GA prop airplanes, take-off is executed with full throttle and high rpm. The usual reasoning is that this way, we leave the first few hundred feet, where failures are most severe, behind as ...
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This concerns the GE90X fanjet engine which generates 130,000 LBS of thrust at takeoff [duplicate]
This concerns the GE90X fanjet engine which generates 130,000 LBS of thrust at takeoff.
But for this example the engine is secured to a test mount, and under "full throttle", the thrust ...
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How to calculate turbojet thrust at variable altitudes and mach numbers?
I am interested in developing a flight model in jbsim. jbsim requires a thrust table similar to as follows, with varying mach and altitude numbers (with thrust as a fraction of max):
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How much thrust is required for a Boeing 747 to "keep flying" at 4 km altitude?
Not full power, just enough to keep the plane moving at 4km altitude.
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Why can't you have sail-powered airplanes?
So, sailing boats take the kinetic energy of a crosswind and turn it into thrust by using their sails as lifting surfaces, and the discussion I had in the comment section of this question made me ...
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