Questions tagged [aircraft-design]

For questions about how certain features of an aircraft affect its performance and function, such as engine type or wing configuration.

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12 views

Sutherland's law for other gasses

Sutherland's Law seems to be a fairly well-accepted relationship between dynamic viscosity and temperature and was originally created to work for ideal gases, though it is often extended to be used ...
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How to decide drone motors?

I'm planning to design a quadcopter with a payload capacity of 5KG. I would need the thrust power from the motors to cater for at-least 7KG (max, worst case) with extra part weights. I would like to ...
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48 views

How to know the material of key-top?

There are keys (push buttons) on the front panel of an avionics device that fits inside the aircraft cockpit. I need to know the material of which those key-tops are made from. I can guess the ...
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44 views

Can an empty aviation fuel tank blow up

At the end of the James Bond movie View to a kill, the aeroplane runs out of fuel - both the propellers stop and the plane glides. There are holes at the bottom of the tank so all the fuel has ...
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36 views

Is it true that pre-jet air planes used to fly much lower? If so, why?

I watched a video on the Concorde the other day. In it, they talked about the history of airplanes, and how the jetplanes now started flying "above the weather", and that the propellar-...
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1answer
885 views

How does a helicopter hover

I am wondering how a helicopter manages to stay balanced and stay in one spot while it is in the air. I understand that there is a second rotor that is used to counteract the angular momentum and also ...
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1k views

In case a plane stalls, what should stall first, the tip or the root of the Wing? Why?

In case a plane stalls, what should stall first, the tip or the root of the Wing? Why?
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what is the difference between jblade, qblade, and xflr5 softwares?

I am working on a propeller design, and I've came through Jblade which helped me in the airfoil design, yet as I can remember, xflr5 can also do this... doing some internet search, i found that Jblade ...
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13 views

Where can i get the aerodynamic data of aircrafts for controller design and testing?

I have some research papers on aircraft controller design that i want to simulate, but no system data is given in the research paper itself. I am also unable to find the aerodynamic data for any ...
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What engineering obstacles would need to be overcometo make a hot air balloon bigger than the largest made?

Average hot air balloons have a diameter of about 18 m. The largest out there is roughly 32 m. My question is, are there any reasons other than fuel concerns that would prevent having a larger ...
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1answer
42 views

Aircraft Longitudinal and Lateral Transfer Function Terms

The figure shows input and output variables for both longitudinal and lateral stability transfer functions. I completely understand what each term stands for but I was wondering what would be the ...
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1answer
29 views

Using RC scale-down model to pre-test aircraft design

I'm a bit involved into building an actual airplane. And while the guys go conventional ways, I'm trying to look around to see other solutions. One of that is to try and use and RC scale-down model (...
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For a tangent ogive, given a radius, can you determine it's length?

A tangent ogive body has a specific radius for a given length, so how would you determine length if only given the radius?
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Boeing 737NG pickle fork cracking. What determines the fastener layout?

Boeing 737NG aircraft are currently being checked for cracking in the "pickle fork" assembly that attaches the fuselage to the wings. The affected joint has 4 fasteners that attach the fork to the ...
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48 views

How do you determine the L/D ratio of F-117 Nighthawk?

I was trying to look for an L/D ratio published everywhere on the web and I can't seem to find it (for a project). Since I couldn't find it, I wanted to try calculating myself. Can't seem to find $C_l$...
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88 views

For how long could a plane handle turbulences?

Some days ago, I took a plane (Airbus A330) for a pretty long flight - around 8hrs. During the flight, we experienced some turbulences and I thought : what if the turbulences last the whole flight? ...
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55 views

Heating the air inside a turbojet instead of combusting it

Would an aircraft that uses propellers for movement but with a turbo jet like structure where the ignition chamber only heats the air a bit, similar to a hair dryer instead of releasing fuel and ...
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2answers
136 views

Compressing the air thrusted by an aircraft's propeller through a cone like tube

If I had an aircraft that used propellers for movement and took the air from the front running it through a tube that gets very small towards the end, would it have any impact on the speed? Would the ...
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5k views

Multiple Varying cross section beam deflection

How do we calculate the deflection of a cantilever with two or three cross-sections, and different forces acting at the end of each section?
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Batteries for electric airplanes [closed]

I'm interested in the development of electric small airplanes with 4 or 6 seats, that could really happen in the following decades. One of the main problems related to this project would be the ...
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67 views

PID control for UAV [closed]

I'm working on a deltawing model airplane where I want to implement a PID controller to stabilize the pitch, roll and yaw (which are only controlled by two elevons). However, I don't know too much ...
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1answer
103 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
65 views

What action does a 3 axis gyro stabiliser do to stabilise the drone?

A gyro measures the angular velocity of a drone around 3 axes: yaw, roll and pitch, but what physical change does it make to the drone after measuring this value to give it stable flight? As it is a ...
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1answer
164 views

What is the importance of pitch ratio? And why is the value different for different aircrafts?

I tried looking online, but all I can find is what pitch ratio is, butI can't find anything related to the question above. Help will be appreciated.
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What technologies prevent drones from being as efficient as birds? [closed]

We have large scale aircraft with long endurance and much higher speed than birds. But it seems that aircraft of comparable size to birds (i.e. drones) have much lower endurance, top speed and flight ...
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1answer
97 views

Name of a keel between the bilge keel and the main keel

I'm working on a seaplane and find myself doubting about the specific nautical term for a keel placed between the bilge keel and the main keel. This might be a bit academic in nature since I have a ...
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Do all airfoils have a lift curve slope of $2\pi$?

I know that according to the thin airfoil theory all airfoils (symmetric or not) have lift curve slope of $2\pi$. I also know that finite wings should have less inclined lift curve because of the ...
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847 views

Wingspan formula for an Ornithopter

How do i figure out what the wing area/sqft needs to be for a functioning wing-flapping ornithopter? Lets say for example there is 500# of force moving the wings up and down, and the wings and ...
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318 views

Can a blimp enter Mar's atmosphere as a glider?

I saw a high altitude jump where someone had exceeded the speed of sound before the air slowed him down enough to deploy a parachute. While inflated in space could a blimp enter the atmosphere while ...
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2answers
69 views

Lift Requirements for Hybrid Airship

so I am very interested in flying. I don't have any formal education in the topic so take my questions for what they are. I was thinking about VTOL aircraft and the current state of such machines. ...
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4answers
353 views

Are rocket engines practical for commercial aircraft?

What are the prospects of seeing rocket engines become the standard for commercial aircraft? It might be a dumb question; I really don't know all that much about the topic. The reason I ask is that ...
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1answer
549 views

Will helium gas lift more weight in air when it is spread over large volume compared to equal weight heavily compressed small volume?

Is it possible for a weather balloons filled with helium gas to lift the weight of itself and a helium tank(highest psi possible) which can fit the volume of the lifting gas in it? Assuming a typical ...
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113 views

What is that airplane headphone socket?

I recently flew on a A380 and I saw this interesting socket. Could someone explain to me what is the purpose of these 4 golden connections?
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171 views

3D matrix for staggering 5 ten degree wide bands of angle of incidence shifted by target wavelength and optical path difference in arithmetic series

Today, we came up with the idea of creating a 3 dimensional matrix where I simultaneously stagger 3 times 5 times 5 Fabry Perot band-reject interferometeric filters with ten degree wide bands of ...
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2answers
367 views

How can we prove that Thrust-to-weight ratio depends by max speed?

Raymer (see source below) affirms "Thrust-to-weight ratio is closely related to maximum speed". Why? How can we demonstrate it? Source: Daniel P. Raymer Daniel P. Raymer "Aircraft Design: A ...
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197 views

In Raymer diagram “Take off parameter- Take off distance”, what is the difference among “balanced field length”, “over 50 ft”, “ground roll”?

Raymer in his book Suggests a method to find Wing Loading W/S (for example we consider jet with 2 engines) (starting from specific thrust T/W, CLto, density/reference density etc.). In step 1: he ...
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1answer
66 views

Using propeller downwash for electronics cooling

I have a quadrotor aircraft (4 motors/propellers around a center housing) with some electronics in an electronics housing. Looking to cool the electronics with propeller downwash. I have a vent on ...
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2k views

How an airfoil works

I have read on many sites that for lift to occur, the pressure below a wing must be higher than the pressure above it. This happens by somehow moving air faster over the top of the air foil so the ...
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6k views

If aircraft are pressurised, why do our ears pop during liftoff and landing?

Something hit me during my last flight: our ears feel that the pressure around us changes quickly during liftoff and landing, they hurt more and more until we make them pop. However, the cabin must ...
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2k views

Efficiency in a gas turbine or aircraft engine

Most modern aircraft engines, such as the one depicted below taken from Wikipedia, are composed of several compressor stages which are driven by a turbine (or several), and a combustion chamber in-...
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965 views

What are the advantages of chemical oxygen generation over compressed tank storage?

Chemical oxygen generation (COG) is used in commercial airliners to supply emergency oxygen to passengers and crew if the plane is depressurized. Weight for weight it produces far more oxygen than ...
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106 views

How to store gas on little pulsejet plane?

I am thinking about building small plane with a pulsejet but the engine would need to be roughly 2 cm in diameter. Is it even possible to fit something to store gas on that sized plane? At least for ...
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3answers
401 views

Is a wing that runs the length of an aircraft viable?

I was thinking about fighter aircraft like the Harrier which have thrust vectoring and computer-controlled stabilisation nozzles. Also an anhedral angle on the (small) wings. The aircraft relies so ...
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1answer
1k views

How is fuel mixed with air in a jet engine?

I am working on an idea that involves a jet engine, but I don't quite know how the fuel system works. In a combustion engine like that in a car, you have nozzles that spray the fuel into the piston ...
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824 views

How are wind tunnel models used when designing supersonic aircraft?

There are two things involved: wave drag and boundary layer separation. The wave drag depends on the Mach number while the latter depends on the Reynolds number of the flow. It's easy to maintain the ...
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3answers
732 views

Can superhydrophobic surfaces be used to reduce drag?

I am mainly interested in reducing drag in aircraft and I have an idea that I want to learn more about... Can a superhydrophobic coating reduce drag in water-craft such as boats and submarines? If ...
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915 views

Could air-launched space planes reach escape velocities?

Rockets like the Ariane 5 weigh hundreds of tons, but with about 85% of that weight being fuel, the payload fraction is only about 3% (~10-20 tons). Virgin Galactic is building suborbital space ...
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555 views

Possible Hazards of Software Controlled Systems (Ex. Airline GPS/Elevator)?

I am currently reading through a book on Software Engineering principles, with a lot of the content having to do with proper approaches to software development methodologies and project management ...
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134 views

Did Otto Lilienthal ever experiment with non-human-powered aircraft?

Otto Lilienthal, sometimes hailed as the first aviator, became famous for his many gliders, which pioneered new experiments in aeronautics. However, powered aircraft didn't take off - pun intended - ...
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886 views

What are the engineering challenges in WIG craft development?

Wind In Ground (WIG), is an old concept. In short: Wing-tip vortices create an additional drag on the aircraft known as the induced drag. However, when the flying craft (or bird) flies close to the ...