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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Minimal width of a carbon fiber shell to hold a flying airship

In Aves Æternæ: Building Perpetual Flying Machines you can find the specs for an airship with a rigid carbon fiber shell. It would be around 4m long and 2m wide and high, weigh around 10 kg empty (0 ...
2 votes
5 answers
98 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 ...
0 votes
2 answers
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Is a centrifuge force-based levitation system operable in the real world?

In the sci-fi comic Betelgeuse, the artist Leo presents a flying car with an unusual system for levitation and propulsion. The interesting point is that at the end of the comic, there is a page on ...
1 vote
1 answer
73 views

Which optical filter to use for flat black non-glare aerospace indicator?

I am currently designing a LED light indicator for use in an aircraft cockpit replica. I’m asking for expert advice on the type of lenses to use in order to get a result similar to shown pictures. ...
8 votes
6 answers
5k views

Can we add treadmill-like structures over the airplane surfaces to reduce friction, decrease drag and producing energy?

I am curious about a method to enhance the efficiency of passenger aircraft during cruise speeds by integrating treadmill-like structures on the fuselage and beneath the wings without changing the ...
0 votes
0 answers
96 views

SU2 vs OpenFoam for highly unsteady aerodynamics. Suggestions?

I am trying to simulate aerodynamic interactions between high speed propeller downwash and wings of a cruising aircraft. Confused between OpenFoam and SU2. Open to other opensource software ...
0 votes
0 answers
30 views

Calculate Air Conditioning Duct Pressure from Sources and Users

I am currently modeling a high fidelity simulation of Boeing 747-200 for a flight simulator, and I am now at the stage of programming what is essentially the HVAC system for the aircraft. I will try ...
1 vote
2 answers
277 views

Infinite life of a material, Fatigue Strength

After 10^6 cycles a component is considered to have infinite life. What makes 10^6 cycles a deciding factor for infinite life? Why not 10^8?
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0 answers
34 views

Pitot and static port placement - How to choose the ideal location

Forgive the this topic placement as it might be similar to other older ones (Although I a bit sure that the main contents might be different than other older ones). In the upcoming days I will have a ...
1 vote
2 answers
195 views

Why does the air in a jet engine not flow out of the front?

It is my understanding that jet engines work via the ,”suck squeeze, bang blow process”. The main fan introduces air into the engine, and the compressor blades squeeze this air into a higher pressure ...
0 votes
1 answer
84 views

What would cause more stress the airframe of a 757/767: 550 mph at 1,500 feet, or supersonic flight at 50,000 feet?

I was reading over some threads on metabunk.org about the 9/11 "Truther" Movement and it was brought up that a DC-8 was flown at supersonic speeds at 50,000 feet as an explanation for how ...
0 votes
1 answer
59 views

Failure criteria for CFRP single plate bolted joint

Which equation can be used to find failure based on ply orientation. Tension,shear & bearing faliure to validate against fem analysis
0 votes
1 answer
129 views

In an aircraft, should I connect flanges of wing spars' to the fuselage, or webs of wing spars' to the fuselage?

I am actually trying to understand which option is going to be a more relaible for the wing-fuselage attachment. Should I choose a connection between the flanges of the spars within the wing to the ...
3 votes
2 answers
109 views

What is the reason for forbidding liquids for cooling in drilling on cfrp/Al or cfrp/Ti stacks?

I recently did some research on the effect of cooling on CFRP/Al7075 drilling.But I read somewhere that liquids are forbidden for cooling operations on these multi layer plates !!! , And I wanted to ...
1 vote
5 answers
242 views

If an aircraft's wing blows air downwards, how is the momentum conserved in level flight?

An aircraft's wing generates force of lift by directing the oncoming airflow down. How is this momentum balanced when the aircraft is not climbing, but maintains level flight?
0 votes
3 answers
74 views

Are wind powered drones and platforms possible?

A glider is able to fly unpowered indefinitely so long as it can exploit nearby thermals and the like to stay aloft. The world record is 3,008km so perhaps there is a practical limit. I imagine this ...
4 votes
2 answers
12k 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?
2 votes
1 answer
52 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 ...
0 votes
2 answers
274 views

Will a lift force be created by the Coanda effect if high velocity air flows under a half-toroid shaped saucer? [duplicate]

I would like to know if a lift force will be created by the Coanda effect from high velocity air that is directed under a half-toroid shaped saucer by a centrifugal impeller. To illustrate how such a ...
1 vote
1 answer
35 views

If an airfoil underwent horizontal loading, would it stiffen the airfoil? [closed]

I am designing a wing for a Vertical Takeoff and Landing aircraft. I am trying to choose a wingtip winglet for my aircraft. One of the option is a aft-swept wingtip winglet. However, this structure ...
2 votes
0 answers
388 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 ...
-1 votes
1 answer
55 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 ...
-1 votes
2 answers
44 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-...
4 votes
1 answer
955 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 ...
4 votes
2 answers
3k 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?
2 votes
0 answers
219 views

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 ...
1 vote
1 answer
2k 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 ...
2 votes
3 answers
71 views

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 ...
1 vote
1 answer
591 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 ...
0 votes
1 answer
47 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 (...
0 votes
1 answer
228 views

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?
3 votes
0 answers
350 views

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 ...
0 votes
1 answer
153 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 $C_l$...
3 votes
2 answers
376 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 ...
10 votes
3 answers
1k 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 ...
6 votes
2 answers
1k 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 ...
1 vote
1 answer
205 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 ...
0 votes
3 answers
99 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? ...
-7 votes
3 answers
429 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 ...
0 votes
1 answer
333 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.
5 votes
1 answer
112 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 ...
4 votes
1 answer
196 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?
0 votes
2 answers
78 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 ...
1 vote
0 answers
55 views

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 ...
1 vote
0 answers
74 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 ...
0 votes
1 answer
72 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 ...
0 votes
1 answer
80 views

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 ...
3 votes
4 answers
421 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 ...
2 votes
1 answer
114 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 ...
2 votes
3 answers
1k 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 ...