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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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2
votes
3answers
197 views

Does a biplane need wing twist?

Does a biplane need wing twist? I understand wing twist is used to: creat a soft/partial stall ( hopefully create a partial stall before a full stall) balance the wing so a smaller horizontal tail ...
2
votes
2answers
225 views

Is it useful for twin propeller airplanes to have twin vertical stabilizers, in line with the propellers?

In some twin propeller airplanes, there are two vertical stabilizers which are on the same line as the propellers. Is this shape helpful in terms of efficiency? Like this one (twin boom tail):
0
votes
1answer
124 views

Is lift generated only by wings? [duplicate]

In modern aircraft is lift only generated by wings or can other parts of fuselage generate a significant amount as well, to the point it needs to be accounted for when designing a plane?
8
votes
1answer
490 views

What is this hole on the F-22 Raptor?

I noticed this little hole that is right in front of the cockpit window of the F-22 Raptor. In some photos, it seems to be closed, while in other photos, it's open. Does anyone know (or think they ...
3
votes
2answers
59 views

How do you calculate the vertical and horizontal tail volume if you have Vvbar and Vhbar?

I know the general formulas for calculating the horizontal and vertical tail volumes. Unfortunately, I only have Vvbar and Vhbar. I’ve checked through multiple textbooks and I don’t know why I can’t ...
5
votes
3answers
360 views

What causes fuel gauges to be untrustworthy?

I went on my first flight yesterday (Cessna 152), and I was told not to trust the fuel gauges and to check fuel levels manually. The instructor said that the only fuel gauge reading that I can trust ...
0
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0answers
50 views

What is the reason for circulation of air around an airfoil? Based upon the circulation of air, why are airfoils shaped the way they are? [duplicate]

Foreword: I am an Aerospace Engineering student and next year is my third and final year, starting September 2019. I was taught approximately 2 semesters ago that the correct theory of lift is that ...
3
votes
1answer
81 views

What is the comparative roughness of fabric surfaces?

"The Design of the Aeroplane" by Darrol Stinton (1983) lists comparative roughness of aircraft skin material (pg 154). Unfortunately it does not list dope & fabric. What is the comparative ...
2
votes
2answers
175 views

Can we trade some efficiency to curb high-altitude emissions?

Considering our problematic issues, Emissions at high altitude Contrails ~10,000 premature deaths per year from airline emissions This is an area of concern where it's worth asking some stupid ...
25
votes
11answers
13k views

Why force the nose of 737 Max down in the first place?

Can someone here explain a pretty basic question that I have had ever since this controversy came to light? I don't understand why any aircraft manufacturer, engineer, software developer, would make ...
1
vote
1answer
58 views

What should be my basis for selecting an airfoil?

We're in the process of designing a trainer aircraft and I wanted a high wing aircraft. We calculated this from the profile graphs given on the reports.I know these aren't super accurate since I just ...
3
votes
2answers
105 views

What would be the ideal plane specs that minimizes consumption for 1000 kg of cargo payload (slow speed, wing span, whatever..)?

Speaking of electric planes, I wonder what'd be the optimal specs if the only variable that we'd try to optimize was consumption (assuming a 1000 kg payload and 600 mile legs, unrestricted runway)?
2
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1answer
110 views

Where is the midspan airfoil located on the 737?

The 737 has a root airfoil, two midspans, and one outboard. Is the midspan located under the fuselage or between root and tip?
1
vote
1answer
114 views

How is the flow of air through a NACA submerged inlet determined?

This question pertains to the design and/or selection of NACA submerged inlets. I am trying to understand what kind of airflow would enter a NACA submerged inlet/scoop and am looking for a good ...
3
votes
2answers
219 views

Does a skinless fuselage add to the likeliness of an unrecoverable spin?

While at Air Venture this week, I happened to hear a pilot of a small experimental airplane say that he liked the skinless (Naked) look his airframe had at one point during the build, but that he ...
39
votes
13answers
8k views

Other than a swing wing, what types of variable geometry have flown?

We're well familiar with swing wings, on small and large aircraft from both the east and west. What other types of variable geometry have been tried?
27
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5answers
7k views

Why is the UH-60 tail rotor canted?

The Sikorsky UH-60 (S-70) has a tail rotor that is canted 20 degrees upwards. Why is that? Picture source
3
votes
1answer
193 views

Topics for high school chemistry project (IB Chemistry IA)? [closed]

I have to do an IB Chemistry IA and I wanted to relate it somehow to aviation; however, I can't do anything super complicated though because I'm only a high schooler. Here are some possible topics ...
1
vote
2answers
400 views

Why did Boeing keep using yokes while Airbus moved on to sidestick?

The first Airbus had yokes but they changed to the sidesticks after a while But Boeing is still stuck with yokes even with 777-300ER decades later. The sole purpose of the yokes are seemingly for the ...
3
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4answers
355 views

What would be the impact of replacing the engines on the 737 MAX, not just reworking MCAS?

There has obviously been a lot of focus on the MCAS failure following from the 737 MAX crashes. However, the MCAS appears to be a compensating control for design decisions, specifically the ...
3
votes
1answer
115 views

Why are no HAPS (High Altitude Platform Station) solar planes of a biplane design?

HAPS are fragile due to weight constaints, e.g. NASA’s Helios. Biplanes are more robust. Although biplanes have high drag, HAPS only need to move slowly because at their operating height the wind ...
0
votes
3answers
176 views

What's the relation between speed of an aircraft and takeoff distance?

I'm making a tool that when given : weight of aircraft , takeoff speed , runway length and some other parameters , it analysis the takeoff performance and states whether using the brakes now is safe ...
0
votes
1answer
166 views

Why is the aviation industry taking so long to move away from the tube with wings model? [duplicate]

The industry is spending billions on maximising fuel efficiency and reducing other costs associated with the tube-with-wings model. When will novel designs like semi-dirigible and lifting body arrive, ...
2
votes
1answer
103 views

Does a RC aircraft require suspension in landing gears?

we engineering students are preparing for a particular competition with dimensions of 170 in. (length + breadth + width) for that competition we require landing gear but for that are we supposed to ...
9
votes
5answers
5k views

Do aircraft cabins have suspension?

On cars, we have 'shock absorber' suspension that decouples the passengers and loads from the road vibrations, bumps etc. On planes do we have any form of suspension that decouples the passengers &...
1
vote
0answers
80 views

Are there design guidelines for sizing vent/surge tanks?

Could someone explain the sizing process of Vent/ Surge tank of Aircraft fuel system? I understand the Vent tank is to collect fuel overflow from the main fuel tanks. The reason could be due to Fuel ...
0
votes
0answers
75 views

Could a tail rotor serve as a spin breaker for winged aircraft?

It seems that yaw, more than pitch or roll, creates the greatest wing asymmetry in a spin. If the spin progresses to the point where it cannot be broken, some aircraft are equipped with parachutes to ...
-1
votes
2answers
360 views

Could a BV-347 be upgraded by extending the wings?

The CH-47 Model 347, also referenced as BV-347, was a helicopter that utilized a wing for forward flight and to carry external payloads. Could the wings be extended and engines on the rear rotor ...
-4
votes
2answers
224 views

When are more engines better than not on a plane?

A model of this airplane was used to carry a space shuttle. In this picture below the airplane had a few extra engines added since then. How is the number of engines decided on an airplane? Why not ...
12
votes
2answers
5k views

Why does the Antonov AN-225 not have any winglets?

Winglets provide a lift boost that would be useful to a plane of this size. But the An-255 does not have any winglets. Why is it so?
3
votes
3answers
220 views

Is it better to have the engines center or apart on a plane?

Are there any advantages or disadvantages to having the engines closer or farther to the center of the plane? How is the ideal engine spacing determined length or span wise for performance? Related: ...
4
votes
1answer
162 views

Does a tandem ultralight need flaps on the rear wing if the front wing has flaps?

Does a tandem ultralight need flaps on the rear wing if the front wing has flaps? I understand that most Rutan canards don't have flaps as I was told if the main wing has flaps, the canards need one ...
1
vote
1answer
41 views

What is the best or most popular way to reduce wing tip vortices on an ultralight operating at 600-800k Re?

What is the best or most popular way to reduce wing tip vortices on an ultralight triplane, operating at 600-800k Re with fibreglass wings ,10 ft wingspan, gap of 2 chord, chord of 2 ft, 0 stagger? ...
0
votes
1answer
92 views

What would be the advantages and drawbacks of a single-propeller tiltrotor?

When looking at existing tiltrotors, most of the designs use two propellers, sometimes four. helicopters (and light planes), on the other hand, generally use only one propeller. Have there ever been ...
4
votes
4answers
384 views

Why are overwing engines so rare?

This comment to a question about underwing vs rear-mounted engines notes the existence of a rarely used third option: overwing engines. There seems to be very few planes using those. What are the ...
29
votes
3answers
7k views

Why do most airliners have underwing engines, while business jets have rear-mounted engines?

Why have modern airliners converged on a configuration with two or occasionally four underwing engines, while modern business jets have converged on a configuration with two or occasionally three rear-...
1
vote
2answers
171 views

Can cold thrusters/roll posts be used to control/stabilize an aircraft (like a satellite)?

Aircraft use control surfaces to control their motion/direction. Would it be a good idea (i.e., more efficient, less weight, better responsiveness, less drag, etc.) to use thrusters/roll posts to ...
0
votes
3answers
625 views

Would a Chinook helicopter fly better with contra-rotating along with counter-rotating propellers?

Would a Chinook perform better or have any advantage with dual contra-rotating propellers over a Chinook with just normal counter-rotating propellers?
11
votes
3answers
518 views

How does the A350 variable camber system decrease drag?

Just curious how the A350 reduces drag/fuel burn by extending the flaps ever so slightly during cruise. Everything I've read about extending flaps says that extending them pushes the centre of ...
22
votes
2answers
6k views

Which are more efficient in putting out wildfires: planes or helicopters?

A lake is near where both helicopter and plane can access the water and fire. Which aircraft (if you had access to only one) is more efficient in putting out wildfires? Which aircraft is preferred to ...
0
votes
1answer
74 views

Does empennage height above the main wing matter [closed]

Am still in my preliminary design, am already wondering as to how high above the wing should the empennage (tip of vertical stab) be?
2
votes
1answer
317 views

Was the F4F-1 Wildcat ever built?

The original design for the F4F Wildcat was as a biplane, but with the -2 model, it was redesigned as a monoplane. I am wondering if the -1 model was ever actually built, or did it remain as a ...
6
votes
5answers
2k views

If I were to build a J3 cub twice the size of the original using the same CG would it fly?

How big of an engine would I need, if the original is 65hp? What would be the weight of the up-scaled plane? Simply twice the weight? What would be the stall speed? How fast would it go? 75mph? Is ...
5
votes
3answers
259 views

Does fly-by-wire permit smaller tail fins (area and thickness) for jetliners?

To prevent an XY problem, here's the context: A striking feature of the 777 is how small and thin its tail fin is compared to the 747. When I asked about this many, many years ago, someone told me ...
1
vote
1answer
152 views

How did Airbus A380 overcome corrosion issue in which aluminium wiring used? [duplicate]

The corrosion of aluminium is generally recognized to be a major problem. What new technologies or technics might be used in aluminium wiring to get away from the corrosion issue?.
0
votes
1answer
136 views

Would this modified tire work to prespin an aircraft tire? [duplicate]

In order to decrease that initial hit of the tire spinning up to ground speed on the runway, could adding a blades or shape into the tire rim of a commercial plane save on tires by prespinning the ...
4
votes
1answer
534 views

Why do some helicopters have wheels instead of skids?

I have noticed that Black Hawk helicopters have tires, but I have not seen one take off like a plane. When would a helicopter need to use a running take off or landing? When is it determined ...
35
votes
5answers
15k views

Why were the first airplanes “backwards”?

In the question Is the location of an aircraft spoiler really that vital? the accepted answer states "Surfaces behind the CoG act as stabilisers, keeping the nose pointing forward. An aeroplane has ...
3
votes
1answer
127 views

What does the “test result indicator” indicate on a cockpit voice recorder?

I am really curious as to what the “green/red” strip of led indicate and the numbers below it. Having read around the web, i speculated that it could be an audio quality rating scale. Would help alot ...
10
votes
1answer
2k views

Is the location of an aircraft spoiler really that vital?

I was wondering that spoilers in most of the aircraft are always placed aft (towards the tail) the CG location. Why aren't they placed ahead of the wings or near the nose of the aircraft? The same is ...