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Questions tagged [aerospace-engineering]

Aerospace engineering is the primary branch of engineering concerned with the research, design, development, construction, and testing of aircraft and spacecraft.

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Mass of exhaust or Mass or rocket?

This is from Stephen Hawking's latest book; Brief Answers to the Big Questions. The speed at which we can send a rocket is governed by two things, the speed of the exhaust and the fraction of its ...
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Efflux plane location in induced velocity propeller slipstream model giving imaginary number

I'm trying to recreate the model given in "Propeller Slipstream Model for Small Unmanned Aerial Vehicles" in MATLAB and I'm having some issues, mainly with the efflux plane location, and also with the ...
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25 views

What is the cycle of simulation editing?

So this is very general, but... How are simulations for vehicles done? I know that computational fluid dynamic simulations are used, but why are repeated tests of actual hardware done too? Obviously ...
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59 views

Why there are no jets (missile or aircraft) faster than Mach 3.3?

Fastest plane ever built: SR-71 ,Max Speed: 3.3 Mach , Development - 1950s Fastest drone ever built: Lockheed-D21 ,Max Speed: 3.3 Mach, Development -1960s Fastest cruise missile ever built: Brahmos ,...
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Tethered Balloons vs Towers for Wireless Communication

If we use tethered balloons (aerostats) with wireless gateways fitted on them (let's say for Cellular or LPWAN communication), they can provide much more coverage owing to the height they can reach (e....
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42 views

Is there an ideal propeller shape?

Are there theories that assert about the ideal shape (i.e., ignoring structural constraints) of a propeller? Just looking at the shapes that emerge in practice, it appears that both the fluid speed ...
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21 views

How to write the Rotation matrix kinematic equation for the desired motion?

For a given Rotation matrix trajectory $R(t)$, we know that it follows the kinematic equation $\dot{R}(t) = R(t)\hat{\Omega}(t)$, where the hat operator gives a skew symmetric matrix for a given ...
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41 views

Meshing Complex models in abaqus

I'm trying to mesh a model of a morphing wing in Abaqus and have been running into issues. It was recommended that I partition the model into smaller parts, but it seems that the more I try to ...
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1answer
166 views

What is the straightest, longest and strongest pole that could be launched into space?

Which of these poles would be straighter and stronger then the others? These are some poles that are compacted making them possible to send to space. Sending a single solid pole .5km long will not be ...
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29 views

What does 'Analysis Model Value' in NASTRAN optimization mean?

I am new to MSC NASTRAN and PATRAN. I am running a simulation on composite laminate optimization. While creating the design variables for the study, I noticed that there is a parameter called '...
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11 views

Horizontal tip extensions and C-wing design for stability of tailless drone

I am a robotics student and new to aeronautics. My task for a project is to build a flying wing drone with limited wingspan (<1m), 25cm chord at wing root, total load of 2.5kg (1.5kg empty) and ...
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what kind of heat insulation should I provide to a camera mounted externally on a surface facing supersonic flow

i wanted to know if we could estimate the heat of supersonic flow and insulate the external camera accordingly. Are there any transparent materials withstanding stresses similar to CFRP that I can ...
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15 views

Contact Motion Analysis (CMA) [closed]

In this solution Helicoptor Fire Control System CMA is used. For motion analysis we use computer vision and image processing. But what is special about CMA.
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63 views

Is an electric dirigible feasible?

The standard design for an airship is to fill a large cavity with a lifting gas such as helium. However, helium is rare, expensive and it leaks through the skin of its container. I would like to know ...
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Random Vibration: Does Segmenting Bandwidth Affect Validity of Response?

Important bits in bold. I'm planning to conduct some preliminary workmanship vibration testing on a new aerospace device. Unfortunately, this 'product' is too heavy for my small ED shaker table to ...
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50 views

What is the purpose of building multistage rockets, rather then packing more fuel into a single stage?

Reading an article about multistage rockets (not educated at all on the topic), and from the get go it seems to assume they are used/need to be used.
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structural radius for strain evaluation - Propeller Design

What is 'structural radius for strain evaluation' in aircraft propeller design?
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1answer
15 views

Vibe Table: Increase Peak Force Capability?

I'm driving a small, benchtop vibe table (shaker) with two Crown DSI-1000 PA's, and also cleaning my signal with a DBX 231s EQ. Currently running the system at 6.8 GRMS, but I'm looking to increase my ...
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52 views

simulation of an attitude optimal Backstepping controller based quaternion for a UAV in MATLAB

I'am trying to implement this open access research article Attitude Optimal Backstepping Controller Based Quaternion for a UAV I did not find the same result in this paper Can anyone tell me where my ...
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1answer
64 views

Why don't propeller designers use multiple profiles?

I'm designing a ducted fan, and I'm deciding on the airfoil profile. NACA 16-series profiles are well-suited to M > .5 or .6, but they're not particularly efficient at lower Mach numbers. On the other ...
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20 views

Doubt regarding relation between maximum of $||x||$ and $x^TAx$ with regards to attitude dynamics

I was dealing with 3-DOF attitude dynamics of rigid body and wanted to comment upon the following defined function $F$ at its maxima. Consider $F \in \mathbb{R} : F(e_{\Omega}(t)) = \frac{1}{2}e_{\...
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342 views

How do solar balloons work at high altitudes?

I am interested in the challenges that Solar Balloons face when flying. For example, the high altitude could cause drastic changes in: Wind speed Temperature Moisture How does the unique design of ...
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Controller design for a thrust angle constrained tracking for a 3-DOF system

For the given system: \begin{equation} \begin{aligned} \dot{e_x} &= e_v \\ m\dot{e_v} &= mge_3 - m\ddot{x_d}(t) - f \end{aligned} \end{equation} which is the translational part of position ...
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52 views

Can a quadrotor track a perfectly horizontal and straight trajectory?

We know that the only control action provided by a quadrotor system is through the propellers. Now, assume that I want to track $x(t), y(t), z(t) = (t,0,0)$. Can we ever develop a controller which ...
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44 views

car pressure distribution coefficient

I have a small project where I am trying to figure out the pressure distribution coefficient, the lift, and drag coefficient of a car prototype in a wind tunnel test.. This shows the location of the ...
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1answer
20 views

Calculate attitude quaternion from 2 vector measurements

I am using a method proposed by R. G. Reynolds to estimate attitude based on two vector measurements, taken from: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19990052720.pdf Suppose we ...
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Does every engineering design needs to have a complete theoretical backing or may experimental data suffice?

This may sound rather vague on its own so I will explain with examples. The solid booster rockets used by NASA space shuttle used a central bore design because it had a certain characteristic on ...
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22 views

How can I merge the lift coefficient of the main wing and horizontal stabilizer into one lift curve?

I'm numerically optimizing an aircraft in the form of a point-mass model. The lift generated is modelled to come from the two lifting surfaces: the main wing and horizontal stabilizer. As it is a ...
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16 views

Free fluid flow during orbit in response to the differential gravity vector encountered

In a satellite in orbit, in a temperature-controlled, but NOT pressure-controlled environment, what will a slick fluid in one end of a short internally slick tube, that is kept aligned with the vector ...
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32 views

Can I get a graph of the span-wise lift distribution on a wing using SolidWorks flow simulation?

I'm working on a project that is a small cargo rc aircraft.. so i wanted to design the wing spar so that it can withstand the lift force created by the wing.. I know how to use solidworks simulation ...
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Need some advice, control system animation. Appreciate some help!

I would like to have a 3d simulation of a helicopter landing on a ship. I thought about using matlab for this, as a far as I know you can connect models from Simulink to virtual worlds using blocks, ...
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83 views

Would a partial space elevator work? [closed]

Background The normal space elevator (that reaches from the Earth's surface to a counterweight beyond geostationary) needs a material that's strength/weight ratio is better than any material we have ...
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1answer
98 views

How to design the right input to obtain a desired output for a linear system?

If I have a state-space model, so that the A, B, C and D matrices are known, how can I design the right input u, so that y is a custom signal, for example, a sine wave with constant amplitude? $\dot{...
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164 views

Beam element stiffness matrix for variable area cross section with mass and shear center not coinciding

I would like to find the full (12 by 12) Timoshenko beam element stiffness matrix for a variable cross section with mass center axis and elastic center does not coincide. I have the full stiffness ...
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3answers
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Aircraft carrier arresting cables

I recently was at the Naval Air Museum in Pensacola Florida. There are lots of models of aircraft carriers, including the latest class (Gerald Ford class as I recall). This latest class has ...
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What is the theoretical relationship between sound and mass with respect to the sound barrier as a max velocity?

First post here, forgive me any faux-pas. In regards to compressible flow and accelerating a mass flow, such as in a converging nozzle, I know that you can't accelerate a mass past the speed of sound (...
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699 views

What is the difference between shaft power and brake power?

I know little about internal combustion engines and I feel a little confused about brake and shaft powers. I read a book that only talks about shaft power, and other that only talks about brake power, ...
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1answer
74 views

What filter is this?

I am implementing a second order filter. It simulates hydraulic servo on an airplane. Its about 35-40 years old. What confuses me is the notation. Like "2(.7)(52)S", what does it mean? If its just ...
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Could a Fuel Breathing Engine Rather Than an Oxidizer Breathing Engine Work?

Here on Earth, the atmosphere is ideal for jet engines which combust a fuel using the native oxygen as an oxidizer. On another planet, might it make sense to carry oxidizer in the fuel tanks and scoop ...
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1answer
25 views

Development of an interstellar mission: should I design the propulsion system or the main hull of the ship first?

I am currently developing an interstellar mission for a school project. I am thinking whether to design the propulsion system (Bussard scoop) or the main hull and structure of the spaceship first. ...
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75 views

How do jets/airplane cold start?

If a jet starts in extreme cold, i.e cold starts, then the jet cannot power the heat exchangers to heat the fuel. Then how do they heat the fuel to start the jets? Obviously you can't use batteries/...
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Is brass a suitable material for a paraffin + GOx hybrid rocket motor?

My school doesn't have facilities for working with steel (due to health and safety), but they do for brass. Therefore, my options are outsourcing the work, or using brass instead. So I was wondering ...
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30 views

Given Pitch and Roll in one Heading, convert to co-planar pitch and roll for North

I have been pouring through countless articles about Euler's angles, rotation matrices, Rodriguez Rotation Formula, Quaternions, trying to understand how to generate an algorithm for this problem and ...
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1answer
61 views

Propeller design

I see on internet, that aircraft propellers most effective blades angle only 15 degrees on every blade. Why propellers not use 45 degrees angle on propeller's blade that give more thrust on the ...
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1answer
27 views

Rotation of aircraft's body-frame

There are Tait-Bryan angular changes $(\dot{\phi}, \dot{\theta}, \dot{\psi})$, which describe the angular change rates of the body-frame within the inertial frame (world frame). And then there are ...
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104 views

Advice for designing internal structure of glider wing

I am interested in designing a scale model semi-monocoque wing for a glider. I've done some research on the framework and internal structure. I have found out about the spars, ribs and stringers and I ...
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Axial compressor - change of temperature not proportional to number of blades and their geometrical properties?

I'm learning theory of axial compressors for my summer internship and I find some of the equations puzzling, although I do understand the way they were derived. The equation bellow is for temperature ...
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1answer
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Triple point storage in space travel

Watching Apollo 13 and rereading Lost Moon, Jim Lovell's exciting recollection of the events on the crippled spaceship, I began to wonder. Why does NASA maintain the gasses at the triple point? A ...
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1answer
28 views

Help me find a paper/textbook on axial compressor in turboshaft engine [closed]

I'm trying to calculate the values of pressure, temp, speed and density of air going through an axial compressor (12-stage) a helicopter. I've read a few bachelors' thesis and papers but wasn't able ...
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71 views

Wind resistance inside turbulent flow (“prop wash”)

I have an object that is launched from the side of a plane (it is a flare). The question is: what does the flare do while it is proximate to the plane? Will it hit the tail? After accounting for ...