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Questions tagged [aircraft-design]

Questions about the different choices that aircraft designers (typically aerospace engineers) make in order to create an aircraft.

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Why do stealth aircraft generally lose in maneuverability?

Whilst stealthy built aircraft have (or claim to have) many anti-detection systems, they seem to have to compromise on less maneuverability features, and even have to keep their missiles inside, not ...
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2answers
167 views

Must quadcopters have the same propeller sizes?

I was flying quads today and it just suddenly popped up into my mind — do the propellers all have to be the same size in quadcopters? Mine are, but What if two propellers were larger and the other two ...
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171 views

What is compressibility drag?

I don't mean wave drag here. What is compressibility drag, which is understood to be a form of miscellaneous drag?
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125 views

What is the feasibility of solar powered drones?

What is the feasibility of solar powered drones? From my understanding, solar panels are becoming more and more efficient, in terms of weight vs energy captured, and in terms of surface area vs energy ...
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0answers
27 views

How can I use the “control hinge-moment coefficient due to tab” for sizing a trim tab on an elevator?

I calculated the control hinge-moment coefficient due to tab by using the dimensions of a tail and its elevator. However, the trim tab dimension parameters in the calculations were approximated values ...
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1answer
294 views

Why aren't there any jets with horizontal-stabilizer-mounted engines?

Looking at the spectrum of where jet aircraft put their engines, there are examples of almost every place that could conceivably used to carry a jet engine: slung under the wings buried inside the ...
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1answer
98 views

What is the function of a sweep cable?

This is Goat3 ultralight with sweep cables,what is the fuction of these sweep cables?
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1answer
200 views

Which airfoil would be optimum for a glider?

The glider I am designing has a mission requirement to fly for as much time as possible. It will fly in the low Re range of about 150,000 to 250,000. While comparing different airfoils I am looking ...
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0answers
38 views

Does Froude Efficiency represent an upper bound for propellers in certain flight / aircraft conditions?

I used the Simple Propeller Theory to calculate the Froude Efficiency for my theoretical propeller-driven craft (at 65k feet). Here are the results: https://ibb.co/kPPqzU. My results were that, for ...
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2answers
166 views

What was the first aircraft designed with a plug-system fuselage, and why?

Nearly all modern transport aircraft are designed with a plug-system fuselage, allowing longer and shorter variants to be built by adding or removing plugs. In addition, the plug system simplifies ...
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2answers
167 views

Again, where is the pivot point in pitch

In regards to recent question about neutral point, as being defined as center of lifts from wing and tail, could one also define a "neutral point" for down forces CG AND down force (up elevator) from ...
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2answers
81 views

Could reduced-lift wingtips allow an airplane to generate less wake turbulence?

Would it be possible to weaken the wake vortices generated by a large aircraft (which can be dangerous to smaller aircraft behind the large aircraft, and are the limiting factor determining how ...
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0answers
119 views

Which aircraft/powerplant manufacturers use metric hardware?

The vast majority of airframes and powerplants use U.S. standard/SAE hardware. Which manufacturers of engines and airframes use metric hardware?
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1answer
10k views

Why does the A380 not have front windows on the top floor?

The title says it all. On the 747, the cockpit is in the upper level and in the lower there's equipment (radar, avionics, etc.) But on the A380, the cockpit is in the lower floor and there's no ...
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2answers
1k views

What is the function of the leading edge strip?

I understand the function of every wing part labelled above except the leading edge strip,what is its use in a fabric wing and will the wing function normally without it,if removed?
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1answer
100 views

Why does the Aurora D8 have vents on the bottom of its fuselage?

The Aurora D8 is a concept of an experimental aircraft (not an actual aircraft for now), described in this site. It's discussed in this question here on Aviation.SX. I was watching the embedded video ...
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2answers
112 views

In the attached image of the Hoffman development of Arup design, the wing is shaped in a somehow anhedral way. Why?

Most airplanes of its days had a Dihedral, or a wing thickness tapering with a 'V' shape, this one is the opposite, hints exist as done to avoid: 'Dutch Roll', or that the ordinary way will impair ...
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1answer
61 views

What is the relation between hinge moment at the control surface and servo torque? [closed]

I am trying to estimate the required servo torque for my design using hinge moment at the elevator. XFOIL results were as follows- I am getting a Hinge moment of about 0.06-0.08 Nm. for the given ...
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3answers
148 views

Finding the center of gravity/centroid of an airfoil?

I'm in the process of building myself a wing frame out of balsa wood. However, as a high school student that's just started aerospace engineering, I'm not really sure how to go about it in some ways. ...
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1answer
113 views

Difference between Mach buffet and shock stall

What is the difference between Mach buffet and shock stall?
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2answers
3k views

Why aren't there any widebody propliners for the high-density short-haul markets?

Jetliners come in both narrowbody (one aisle) and widebody (two or more aisles) versions, but all propliners, to the best of my knowledge, are narrowbody aircraft. Now, granted, one of the big ...
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1answer
127 views

How do you know the maximum load a control surface can withstand?

source This is a separate strength testing (load testing) of the elevator of an airplane, how was the load determined? How did the engineers determine the maximum elevator load?
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1answer
50 views

Accounting for torsional forces during wing load tests

According to this aviation.se question, wing load tests are done by placing weights on the wings (upside down). This unfortunately only tests the wings bending loads (for cantilever wings) and the ...
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1answer
99 views

What are the rules of airfoil thickness from root to tip on tapered wings?

I'm doing some research on wings and airfoils used in the 30s and 40s, and I'm trying to understand the rules about airfoil proportional thickness changes across the wing (root to tip) on tapered ...
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4answers
347 views

Does the required torque to spin a propeller increase with RPM?

I‘ve currently been experimenting with different propellers: 12x12 prop, 16x12 prop (both two blades) and a 22x14 (6 blades) prop. They were propelled by a 2.4 kW electric motor with 260 kV on a 6S/...
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0answers
98 views

In xflr5,how is the value of Fz calculated?

I am building an conventional plane with AR=6 and I find the wing area,A.So I have selected an airfoil for building my plane that is sd7062. Using xflr5 I got a cl vs alpha graph and I took the cl ...
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0answers
43 views

Is there any fixed-wing UAV common research model available?

Is there any source of structural specifications data available for a particular fixed-wing UAV, that can be used for comparison with a resulting structure, obtained by a structural optimization ...
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3answers
574 views

Why is the A380 a double-decker rather than a longer airplane?

It seems like making the A380 a double-decker increases the cross-sectional area of the fuselage, thereby increasing drag on the airplane. Wouldn't it be more efficient to fit so many seats in a ...
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3answers
220 views

Can an APU be designed to also provide emergency thrust in the event of a double engine failure?

Commercial airliners seem to be moving towards twin jets with incredibly powerful 100,000+ lb thrust engines becoming available for use. Would it be possible to design the APU to provide enough ...
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1answer
115 views

Where is the wing sweep angle measured from?

If you look at a 747 planform wing you see something like this: In several aerodynamics and aircraft design text books they use the wing sweep angle as an important parameter to measure the wing ...
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2answers
186 views

Do stall strips mean that wing washout is not required?

The Wikipedia page on stall strips states that AA-1 Yankee airplanes used stall strips to avoid tip stalls (and spins) because wing washout couldn't be used. So my question is: can two stall strips ...
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0answers
72 views

What‘s the diameter of the engines of the Airbus E-Fan?

does somebody know the diameter of the E-Fan‘s engines ? To me the look like around 80cm or what do you think ? Also, with more and wider blades and 60 kW motors instead of 30 couldn‘t they get much ...
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3answers
504 views

How many parts does the latest-generation 737 share with the original 737?

There is an old paradox which states that if a boat sails round the world replacing worn out parts as it goes, once it has replaced all of itself is it still the same boat? I choose the 737 because ...
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1answer
62 views

How do the vortices affect the flow of the horizontal stabilizer upon leaving the wing?

Other than the downwash effect, what other factors that affect the flow to the horizontal stabilizer? such as Dynamic Pressure? Air Flow Disturbance?
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3answers
12k views

Why does this 757 have a propeller engine attached to the fuselage?

I saw the following photo of a Honeywell Aviation Services Boeing 757-225: If it's not a fake, the airplane has a propeller mounted on a pylon on one side. What's the purpose of such strange design? ...
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1answer
166 views

How to determine the direction of rotation of components inside a gas turbine engine using the blade profile?

I am new to Gas turbine Engines. As of now,I am trying to understand the gas turbine engine DGEN 380 by the manufacturer Price Induction. So I have identified the components such as Intake fan,...
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1answer
201 views

Why are many early gliders high-wing designs as opposed to newer designs?

Many early gliders were designed with a high-wing configuration. An example of this is the K 8, but many more of the same and previous generations follow this configuration. Later generations (e.g., ...
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1answer
327 views

What will happen if an X shape wings mounted on biplane?

The question is What will happen if an X shape wings mounted on a light biplane? What will happen in the place which upper wings come closer to lower wing?
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2answers
92 views

Where can I find the best site to learn aircraft design on a small scale? [closed]

I am undergraduate student still trying to figure out a lot about Aerodynamics and aircraft design. I am learning how to design rc planes. So the thing I know the weight of my plane which is between ...
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0answers
48 views

Where to find information on weight breakdown for helicopters?

I would be interested in information on the weight breakdown for the different components of a helicopter. How much of the maximum gross weight is related to the airframe, engine, gearboxes, ...
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1answer
206 views

Is the compressibility of air the reason high aspect ratio wings are more effecient

As stated many times here 1, 2, 3 wings generate lift by moving air downwards. This downward air creates an equal and opposite force pushing the aircraft up. High aspect ratio wings have a greater ...
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1answer
127 views

By what scale is Latitude and longitude calculated on aircrafts? [closed]

If we travel by 1 metre on any side how much of longitude and latitude changes? Since the flight is travelling so fast latitude and longitude changes quickly so how do they calibrate it? PS:Is there ...
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1answer
186 views

How do I decide the tail dimensions and the distance between the wings for a bi plane? [closed]

So I am designing a biplane,I know the weight.I want to know what is the lift formula , volume ratio and aspect ratio for a biplane? I know the formulas for monoplane
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490 views

How do you calculate the lift coefficient of an airfoil at zero angle of attack?

Thin airfoil theory gives $C = C_o + 2\pi\alpha$, where $C_o$ is the lift coefficient at $\alpha = 0$. However, I couldn't find any equation to calculate what $C_o$ is which must be some function of ...
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2answers
6k views

Tail Wing Dented—Is it safe to fly?

I’m sitting in the lounge waiting to board this flight. Saw a dent in the attachment of tail wing to the body. Is this common? Also I could be wrong and it is part of the design of the airplane. Any ...
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1answer
334 views

What factors govern the placement of a helicopter's tail rotor (left or right)?

An image search for 'helicopter' indicates that there isn't a consensus on whether to place the tail rotor to the left or the right of the tail boom, although I'm believe there may be a bias for left. ...
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1answer
77 views

How (or where) do I find an airfoil optimized for low reynolds numbers (100,000~150,000)?

Looking to build a RC plane. Because the span is going to be small and the speed relatively low, I estimate the R-number to be around 100,000. Is there an airfoil optimized for that range of Reynold's ...
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2answers
115 views

aircraft display Processors

what kind of Processors and GPU are used for Aircraft display ? Is it possible to use single processor to run all three displays (Primary flight display, Navigation display and EICAS)?
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1answer
186 views

How much thrust could a 400 mm EDF produce?

there's a 195mm EDF from Schübeler that produces 25 kg of thrust at a peak power consumption of 15 kW: https://www.schuebeler-jets.de/de/produkte/hst Now, my question is: How much thrust could you ...
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1answer
658 views

Are there any standards on the dimensions of PFD symbols?

Are there industry standards on dimensions of PFD symbologies like heading, airspeed and altitude? I want to design a 15 inch screen and wonder if there are any standards or regulations regarding the ...