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
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1answer
385 views

What happens to thrust and drag in a straight and level flight?

Straight and level flight means when an aircraft is flying at a constant speed without changing its attitude. Its lift is equal to the weight of the aircraft. It is flying at a constant altitude. Then ...
4
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2answers
167 views

Why are propeller driven aircraft commonly built with a higher wing aspect ratio and a straighter wing angle?

Why do propeller driven aircraft (especially smaller ones like fighters) tend to have a narrower wing with a higher aspect ratio and a more perpendicular wing angle in relation to the body, whereas ...
2
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1answer
94 views

How much extra drag does an external HF antenna incur?

As seen in the picture, some older planes have external HF antennas that run from the fuselage to the tail. Have any studies found the wire to be a significant source of drag or is the difference ...
6
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2answers
269 views

What's This Cable Connecting Cockpit to Vertical Stabilizer in Air Tractor AT-401?

This is a picture of an AT-401 Sprayer Airplane I was wondering what's this steel-string stretching from cabin's windshield to the top of the vertical stabilizer ...
9
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1answer
212 views

Why are the spoilers used as the backup controls instead of ailerons on the Boeing 777?

While reading this question, I ran across an interesting unanswered comment. Why did Boeing choose to use some of the spoilers as mechanical backup controls rather than the ailerons?
13
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1answer
3k views

Why does this Strikemaster have a textured leading edge?

I was at Duxford recently, and spotted a Jet Provost Strikemaster that had a rough texture applied to a portion of the leading edge of the wing. Why was this applied?
1
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1answer
67 views

Wing loading in conceptual design

Is it possible to have a minimum wing loading at climb segment of our design aircraft (air superiority)? Which segment would have minimum wing loading i.e. climb, take off, cruise, instantaneous turn, ...
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2answers
168 views

How much lift is lost by wing dihedral, and can it be fixed?

The loss of lift, though negligible, was mentioned in another thread regarding the angle of dihedral wings. Not knowing the coreect name but will external "ribs" on the wing surface reduce that loss? ...
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2answers
122 views

What will be the lift generated by the in-wing free spinning gyros in this design?

Gyrocopters feature a free spinning rotor that generates lift. In this design I have included four free spinning rotors inside the wing of a Cessna 172. Although it will not allow it to take off ...
6
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5answers
289 views

Why are aerial taxis multirotored, instead of a single rotor?

source -- image shows Volocopter's design I find that in the designs of aerial taxis, particularly in Volocopter's design, the design consists of a system of multirotors. What is the main reason for ...
6
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2answers
298 views

Why are the B-47’s inboard and outboard engines mounted so differently?

The B-47 has six underwing GE TG-190 engines, two on each inboard pylon and one on each outboard pylon. The inboard engines are mounted on a long pylon that extends well below and forward of the wing,...
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1answer
106 views

How much do a DC-9's wings weigh?

How much do the wings weigh? How much does the landing gear weigh? How much fuel does it take to fill the tanks? We, at Confederation College are trying to donate a DC-9 for training purposes and ...
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1answer
74 views

What material and shape should be used for angle of attack sensors?

Does the material and shape of the vane for an angle of attack sensor have to be identical to the material and shape of the wing? What properties should I consider?
3
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3answers
380 views

Why do some helicopters have such complicated flight control mixers?

Image source Some helicopters have a very complicated set-up that mixes flight control inputs to many or all of the swashplate actuators, like in the picture above for the S-76. Why are all the ...
3
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1answer
228 views

Are there modern airplanes with two propellers driven by one single engine?

Except 1903 Wright flyer, are there any other airplane using one single engine driving two coplanar propellers? Coplanar means push-pull and coaxial designs are not in the question's frame. Tilt ...
2
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1answer
141 views

How to design a near vertical take off airplane?

How to design a near vertical take off airplane, conceptually? Say I have an airplane, similar to a Zenith 701. Say that it has a stall speed of 50 mph and a wing area of 60 sq ft, and it weighs ...
0
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1answer
86 views

Refuelling an airbus to maximum

The airbus A350 aircraft when being refuelled seems to drop when the wings are filled.How much is the drop from empty to full.Thankyou
4
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1answer
250 views

On coaxial helicopters, how exactly does the yaw mechanism work?

This question asks how coaxial helicopters achieve yaw. The accepted answer correctly states that this is done by increasing pitch on one rotor while decreasing pitch on the other rotor, which leaves ...
2
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2answers
146 views

What are reasonable values for the position of an airplane's center of gravity compared to that of its center of lift?

I understand that if the center of gravity is in front of neutral point, it is stable. If the center of gravity is behind the neutral point, it is unstable. Based on the diagram, is it implied that h (...
13
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7answers
1k views

Could flaps be raised upward to serve as spoilers / lift dumpers?

I should preface that I'm by no means an aviation person. I'm just in a aircraft knowledge obsession phase and daydreaming about designing my own ultralight (will never happen). The idea would be to ...
4
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1answer
2k views

What is this flat plate sticking out of the tail of Learjet 24D?

What is this protrusion on the tail of Learjet 24D (shown just above the avro museum logo) and what is its function? Learjet 24D Tail closeup Zoomed out image of the Learjet tail Source: images ...
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0answers
60 views

why are tips of airplane wings "bent' up? [duplicate]

Why are the tips of wings on new aircraft folded up? Is it safety or efficiency that is the concern? I have done multiple searches and all I ever seem to get are wingtip shoes!
2
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3answers
242 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
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2answers
311 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):
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1answer
129 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?
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1answer
601 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
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2answers
98 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 ...
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3answers
438 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 ...
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0answers
53 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 ...
4
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1answer
88 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
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2answers
180 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 ...
27
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11answers
14k 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 ...
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1answer
62 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
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2answers
108 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
135 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?
3
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1answer
170 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 ...
4
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2answers
231 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
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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
8k 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
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1answer
563 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 ...
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2answers
877 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 ...
4
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4answers
821 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
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1answer
120 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 ...
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3answers
201 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
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1answer
173 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
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1answer
117 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
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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 &...
2
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0answers
108 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 ...
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0answers
76 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 ...
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2answers
400 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 ...

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