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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2answers
236 views

What are the advantages and disadvantages of a double bubble fuselage? [closed]

Double bubble is mostly used for Cargo Aircraft with 2 intersecting circles which is in other words: they are 2 floor which are used for more space for freight and also passengers. this type of ...
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1answer
131 views

Would a wingtip stall still be bad if there was no aileron there?

If there was no aileron on the wing tip, would a tip stall still be bad compared to a root stall?
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1answer
105 views

Where do these limitations on wingspan come from?

There may be a limitation on the maximum value of wing span in some cases, for example naval aircraft. Airlines have to be able to operate into airport gates of limited width and typical values of ...
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2answers
2k views

Why is the pitot tube located near the nose?

The pitot tube located near the nose could be affected by the boundary layer and could increase the error. Then why is the pitot tube located near the nose?
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1answer
217 views

What is this intake bottom the wing of C-5 and why is it placed there?

There are two intakes bottom the wings of C-5. What are those and why are they placed there?
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2answers
182 views

Does aviation use “style” designers?

When designing a new plane, does aviation industry use style designers like car industry, or are the decisions made by aerodynamicist; will they solely determine what the plane will look like?
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3answers
210 views

How does a variable-sweep-wing aircraft keep wing-mounted payloads straight?

So, a variable-sweep wing is an interesting design, but I am wondering: if the aircraft wing moves back or forward, then the payload's angle will also change. Is there a another rotating mechanism in ...
4
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1answer
346 views

What are these crevices below the wing of B-52 bomber?

What are these crevices below the wing of B-52 bomber?
23
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3answers
3k views

What is this part which is mounted on the wing of Embraer ERJ-145?

Take a look at the yellow parts which are mounted on the wing of an Embraer ERJ-145. What is it? Two closer images: From bottom:
10
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1answer
2k views

What is this part of an aircraft (looks like a long thick pole sticking out of the back)?

On the website of Kenn Borek Air (an airline specializing in Arctic / Antarctic operations), on this page at the bottom, you can see the following picture: It looks like a long thick pole sticking ...
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4answers
274 views

Why would a turboprop be better than an internal combustion engine for a UAV?

Let us consider a UAV, long endurance high altitude (~26,000ft). Why would a user (most probably military) go for a turboprop rather than an internal combustion engine?
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1answer
303 views

Why doesn’t the A320 family suffer from the same design constraints regarding engine placement/landing gear length as the Boeing 737 family?

This answer gives a pretty good description about the design issues which lead to the problems of the Boeing 737 Max (basically the same as in a video I watched a while ago): The landing gear of the ...
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1answer
200 views

What is the reason for different number of front nozzles on commercial aircraft? [duplicate]

As we observe in commercial aircraft, that there are four or two front end nozzles for gas emission in the air. What is the reason for this variable of 4 or 2 nozzles? Why is it not a constant?
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3answers
8k views

If stealth aircraft are invisible to radar, then how does their own Air Force manage them or see them in flight?

Air traffic controlling is a significant deal when it comes to air forces. If a stealth aircraft like the F22 is almost invisible as said, it has cross section of very small metal ball. Then, how does ...
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1answer
116 views

After decades of solid research, mostly led by Robert J Englar, why is Circulation Control, the Circulation Control Wing not in use at all?

Any research on the CCW by Robert J Englar at Georgia Tech from the 60's into the 2000's. Many papers have confirmed Englar's work and in many cases, advanced it. This research has proven extreme lift ...
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1answer
77 views

Why does the elliptical wing planform have two different types of curves?

Generally, I have seen that the planform of an elliptical wing consists of two different types of elliptical curves The elliptical curve towards the leading edge has a lower value for semi-minor axis ...
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0answers
59 views

Do modern aircraft still use load bearing ribs in wing construction?

Modern aircraft are generally of monocoque construction. Does this apply only to the fuselage, or are modern wings made without load bearing ribs as well? Are they just for shaping of the metal skin?
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0answers
31 views

At what range does the turbofan start to become more economical than a turboprop? [duplicate]

By more economical I only mean 'burns less fuel'. I'm under the impression that at optimal cruise speed and altitude a turbofan will burn less fuel per mile per passenger than a turboprop, but I might ...
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2answers
160 views

What is the purpose of downthrust?

Many light general aviation aircraft-- and perhaps many other aircraft as well-- are designed with some of amount of downthrust in the engine mounting, relative to the centerline of the fuselage. ...
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1answer
390 views

What is the exact wing chord length and thickness for Boeing 747?

I can't find this info anywhere and all they give me is the ratio. However, I need the exact/approximate values
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2answers
156 views

For subsonic aircraft, would adopting a higher wing loading decrease drag?

First, let's assume that problems with approach/TO speeds can be fixed by high-lift devices. Here we read that the wings create more drag than the fuselage. So, an improvement seems obvious; shrink ...
12
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5answers
4k views

Why do aircraft of the same model get progressively larger engines as they mature?

For example, the Cessna 172 started production with the Continental O-300 145hp engine but today sells with the IO-360. Granted that engine is more "modern" but 145hp with the O-300 still ...
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1answer
190 views

Is co-flow jet wing technology workable?

Coflow Jet claims that their idea of sucking air from the trailing edge and blowing it out the leading edge improves efficiency. But this looks like nothing but flow control done wrong to me. And by ...
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2answers
95 views

Does an airfoil drag coefficient takes parasite drag into account?

Im trying to understand why does L/D MAX, (the top of the polar curve that computes CL & CD ratio for any airfoil) is also the lowest point of the total drag curve. Im guessing the reason is that ...
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0answers
69 views

Is it possible for a higher aspect ratio wing to have increased drag compared to a lower aspect ratio wing of the same area?

Since increasing aspect ratio while maintaining wing area decreases chord, one can expect Reynolds number to decrease. Are there cases in which the resulting increased coefficient of friction would ...
19
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3answers
9k views

Why do aircraft with turboprop engine have black painted anti-icing system?

Everyday as I watch aircraft with turboprop engines, a question pops up: Why do aircraft with turboprop engines have black painted anti-icing system? For instance:
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3answers
216 views

How does downwash affect angle of attack?

Many aerodynamics textbooks, as well as many answers on here and similar websites claim that the downwash downstream of a wing induces a net angle of attack that is lower than just looking at flow ...
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2answers
150 views

How would a fighter be changed from having static stability to having relaxed stability?

A good portion of aircraft, especially those designed before the 1970's, possessed static stability. However, modern fighters (and some airliners) have been build with relaxed static stability. This ...
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2answers
3k views

Why are longer wings with foldable wingtips used on the B777X instead of lighter ones with original size?

The new Boeing 777X has longer wings to improve efficiency, but has to adopt foldable wingtips to "fit" into all original airports that host its predecessor. Tendentially, longer wings would ...
23
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1answer
4k views

What is this strut in biplane rigging, attached only to wires, not bearing any load?

A few biplanes like the Stearman have a strut parallel to the fuselage, halfway along the rigging's landing wires and flying wires, not fastened to the airframe, not bearing any obvious load. One on ...
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2answers
368 views

If pilot use rudder to roll the aircraft at high AOA in the F4 Phantom then one aileron from one wing and one spoiler from other will be deflected?

I have heard that the F4 Phantom pilots can make barrel rolls at lower speed /higher AOA. They use only rudder deflection and keep the stick column centered (left /right wise)-only pull onto the belly ...
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3answers
306 views

Does the F-4 Phantom use (have) differential horizontal tail deflection?

Is differential horizontal tail deflection used to roll the aircraft around the longitudinal axis along with the ailerons / spoilers and a bit of rudder?
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1answer
118 views

Why couldn't the CRJ100/200 be equipped with triple-string autoland?

The gold standard for zero-visibility ILS approaches and landings is a triple-string autoland system, where the signals from the localiser and glideslope beams and the aircraft's radioaltimeter ...
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1answer
185 views

Can I fly this six motor drone? [closed]

My body weight; 70kg, Drone weight; 50kg, Props length 0.7m, 6 motors (2hp each), Total weight 120kg, Total horsepower 12, Each motor runs 3000rpm, Please can I fly it. Thanks!!! drawing of the drone
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0answers
89 views

Make a 3 engine turboprop electric or steam hybrid aircraft?

Was thinking about this, have a 2 engine regular turboprop with a third electric engine for extra performance (imagine a DC3 like the Conroy Tri-Turbo-Three). The 3rd electric engine would be run from ...
3
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2answers
197 views

How to know the material of key-top?

Posted it here originally. 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 ...
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2answers
196 views

Does dihedral improve roll stability in gusty conditions?

Against roll instability, should I add more dihedral/a high wing? I'm trying to build an RC plane that can handle windy conditions. For that I want extraordinary aerodynamic stability. For ...
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4answers
323 views

Pros and cons of a thin cambered wing?

What are the pros and cons of a thin cambered wing? Does a thin cambered wing suffer from a flow separation bubble on the lower side, at cruising speed/low AoA? Very roundy leading edge, can air ...
13
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5answers
5k views

Why are the guns on the AC-130 not mounted on the underside of the aircraft?

Why must the guns of the AC-130 be on the side forcing the plane to circle the target. Would it not be more practical to have the guns underneath the plane shooting downwards?
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3answers
336 views

Why don't aircraft owners put vortex generators on the top of their flaps to extend single flap lift creation past 40 degrees?

Why don't ultralight/LSA aircraft owners put vortex generators (VGs) on the top of their flaps? I understand that the maximum flap angle for a single lift creating flap is 40°, but 80° with a double ...
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1answer
171 views

What is an augmentor wing?

What is an augmentor wing in the context of STOL aircrafts? and is it still used today? This seems to be a term that I can only find in NASA aerodynamics (specifically powered-lift) research papers in ...
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2answers
362 views

The wing has a pressure gradient along the AB direction, is there a pressure gradient along the CD direction?

The wing has a pressure gradient along the AB direction, is there a pressure gradient along the CD direction?
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0answers
178 views

During WWII, what did internal bomb bays and turret layout look like on flying boats?

I am writing an alternate WWII story, and I was wondering if you fine fellows on this site could help me. I am trying to make a fantasy bomber version of the USN Boeing C-98 Clipper, AKA the Boeing ...
3
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2answers
256 views

What is the reason why dihedrals are used when building a plane? [duplicate]

How does dihedral affect flight characteristics of a plane? I know it increases stability, however is it the only reason why it is implemented? If so, aren’t there more effective methods to stabilize ...
3
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1answer
288 views

What are the differences between battens and ribs?

What are the differences between battens and ribs?
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0answers
138 views

Can a modern airliner handle turbulence forces of +5/-3G?

In the BOAC Flight 911 accident the 707 likely experienced around positive 5G and negative 2-3G. The wings of the 707 were only about as 50% as flexible as the wings of airliners today. How would a ...
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6answers
316 views

Does angular momentum contributes in lifting a helicopter? [closed]

I want to know whether it is possible to make a helicopter with blades that rotate counter-clockwise (CCW) seen from below. I have difficulty understanding the angular momentum in this situation. As ...
17
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4answers
4k views

Are there any aircraft that either fold or employ folding in their design (such as with origami)?

I became curious about origami and its application to aeroplanes and was wondering if there were aircraft that either fold and/or employ folding in their design in interesting ways. Let's limit this ...
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3answers
274 views

Why do many aircraft have both all-moving tailplanes and elevators?

Many aircraft - particularly large commercial airliners - have both an all-moving tailplane (horizontal stabiliser) and elevators. (They also have a small third moving element on the trailing edge of ...
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2answers
235 views

Is it possible to Fly Aircraft on Mars?

I have been fascinated with the thought of flying all kind of aircraft on Mars. To begin, I don't know much about the fundamental things or requistes for flying. Is it possible with the the things we ...

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