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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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4
votes
3answers
4k views

Is aerodynamics study compulsory for building a plane? [closed]

I want to make a plane like a trike. I have a design and some knowledge about plane requirements.
7
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2answers
2k views

Why is the empennage design of this Lockheed 1049E so complicated?

Photo. What is the reason for making the empennage of this Lockheed L-1049E Super Constellation's design look so complicated with two vertical horizontal stabilizers? In my understanding, the more ...
7
votes
1answer
268 views

Why does the MCAS use the horizontal stabiliser rather than the elevators?

The Maneuvering Characteristics Augmentation System (MCAS), found, in two slightly-different variants, on the 737 MAX and KC-46, provides nose-down pitch inputs in certain very-high-angle-of-attack ...
3
votes
1answer
93 views

Why do some airplanes have a vertical rudder hinge while some others are canted?

I was thinking that canted rudder hinges are used for modern aircraft while the vertical ones are used for old slow airplanes. But it seems that I was wrong since the SST Tupelov Tu-144 and the ...
2
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1answer
450 views

What is this “stick” on top of Cessna 152's wing, and how does it work? [duplicate]

What is this device? What is it for? Seems that some variants have only one, while some others have two. Added: As some have two, so what are they? The answers and comments have not explained which ...
0
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0answers
73 views

what are the winglets on C17's air inlets useful for? [duplicate]

the winglets are clearly visible on this photograph, are they connected with air flow instability?
-1
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1answer
109 views

In fighter jets, is the minimum speed calculated with the flaps in the down position or up? [closed]

I asked that question because F16 flying straight and level at minimum speed does not have flaps down. So how is the minimum speed calculated by aircraft designers?
4
votes
4answers
2k views

What is the first fighter jet which was built with twin engine and tail configuration?

What is the very first fighter jet that pioneers the twin engine and twin vertical stabilizers over the engine just before the exhaust (like the F-14, F-15, F-22, Su-35, etc)?
0
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1answer
213 views

What are the holes on the top side of the canard of Eurofighter Typhoon for?

The Eurofighter Canard has some holes on top side. What are these holes for? ?
0
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2answers
192 views

Why the Mig21 don't use the ailerons like control surfaces on delta wings at landings or take off?

Mig21 is a delta wing , so why do not use the ailerons like any other delta's ? For lowering the approach and touch down speed. It is not possible that?
4
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2answers
116 views

How is lift transferred from rotor to chassis (or weight, the other way around)?

I am trying to find out how a helicopter rotor's lift is transferred to the chassis. Equivalently, how is the weight of the helicopter transferred to the rotor blades? While looking for this online, ...
1
vote
2answers
562 views

When a B-2 takes off, does it use some device to ionise the airflow in front it?

At takeoff, does the B-2 use some sort of ionization device in the leading edges of its wings?
14
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2answers
3k views

Why does the Pilatus PC-24 have such a large “Airplane Support”?

The PC-24 has, under the fuselage, a kind of huge support to hold the wings. If we compare with the Citation CJ4 or the Phenom 300, this difference is quite significant. Why??
1
vote
1answer
54 views

Where can Cirrus Aircraft VisionJet Oleo Struts Material and Dimension Specifications be found? [closed]

I am looking to get hold of Cirrus Aircraft VisionJet Oleo Struts Material and Dimension Specifications. Can anyone point me to or share where I can obtain these details. So far, I have been able to ...
4
votes
1answer
303 views

Was the Horten Ho 229 flying wing a three-point-landing aircraft?

The Ho 229's front wheel is visibly bigger than the main landing gear; during landing, did it touch down on all wheels simultaneously, on the front wheel first, or in the normal manner?
8
votes
2answers
183 views

Is autorotation possible from a 0 rpm start at high altitude?

I am working on an enclosure that is to be ejected from a rocket at apogee (10,000') and fall to a target altitude at a descent rate below 20ft/s before releasing its payload. The idea is to have ...
2
votes
1answer
378 views

Why did Lockheed Martin give the F-22 stealth fighter such small fuel tanks?

Why did Lockheed Martin give the F-22 stealth fighter such small fuel tanks while the F-35 got much more fuel capacity relative to its size and single jet engine?
6
votes
5answers
3k views

How much horsepower to weight is required for a 1:1 thrust ratio?

I did a math experiment today, but wanted to verify the results. I wanted to figure out how much horsepower is needed for an aircraft to hover in midair with no wings/lifting body (1:1 thrust/weight)....
4
votes
1answer
159 views

What is the effective difference between top and bottom mounted airbrakes?

What is the effective difference between airbrakes on the top side of jet aircraft (like on the F-15) compared to those on the lower side (like on the A-7)? From Wikipedia. From Reddit. Would pitch ...
5
votes
2answers
309 views

Why are the engines of the Airbus A400M slightly tilted down?

Picture: Youtube. Firstly, are the engines really tilted down? I have tried to check another picture over the net, seems they are really tilted down slightly. But need confirmation from you experts, ...
2
votes
2answers
141 views

Could higher aspect ratio actually reduce gliding efficiency of a smaller glider?

I have been building 1 meter wingspan 100g class free flight mono wing gliders with a chord of around 10 cm and a flying speed of approximately 3 meters per second. So far glide ratios of around 10:1 ...
2
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3answers
161 views

What is lifting force of V-22 Osprey? Is any other than the two rotors?

Picture is from here. Is any other force to lift the V22 other than its rotors? Is any possibility that the power plants their self are not generating thrust? I was just wondered that such short ...
14
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4answers
3k views

How do pilots align the HUD with their eyeballs?

In fighter jets, how do pilots align the HUD with their eyeballs?
1
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0answers
78 views

Why is the horizontal stabilizer of the Lazair swept back? [duplicate]

Why is the horizontal stabilizer of the Lazair swept back? I understand the hinged elevators are perpendicular to the fuselage, but the horizontal stabilizer is actually swept back.
1
vote
1answer
54 views

Calculate parasite drag coefficient from drag polar

The drag polar of an electric-powered unmanned aircraft is $$ C_D = 0.038 + 0.0458 C_L^2 $$ What is the parasite drag coefficient?
14
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4answers
3k views

Why there so many pitch control surfaces on the Piaggio P180 Avanti?

Picture source. I have seen that there is kind of sonic aircraft like B-1B Lancer that used elevator and canard or fins at the same time for pitch control. That quite understandable because it is ...
0
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0answers
81 views

Why does not jet engines have a metal grid in the front? [duplicate]

An aircraft engine can get destroyed if a large object - like birds - enters it while running. I'm probably naive, but this seems pretty easy to solve. Why not just have some kind of metal grid in ...
0
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2answers
85 views

How did the propellers attach on a Lazair attach if the shafts had a woodruff key instead of opposite thread?

How did the propellers attach on a Lazair attach if the shafts had a woodruff key instead of opposite thread? I understand the early Lazair prop shafts had a woodruff key. How were the props ...
1
vote
2answers
149 views

Do ultralight engines need a thrust bearing?

Do ultralight engines need a thrust bearing? Most gas engine applications only have a radial load ( perpendicular to the shaft). Aircraft, not only have a radial load but also an axial prop thrust ...
3
votes
1answer
141 views

How to modify an amateur kit build with wing hard points

I plan on modifying an amateur-built all-metal kit plane so it has a hard point under each wing where various external loads (cameras, probes, etc) can be fitted to (university research). The location ...
4
votes
0answers
103 views

Why were the ailerons of the Fokker Dr. I (Red Baron) located on the top wing?

Photos' source are here: Fokker Dr. I (Red Baron), and here: a Sopwith triplane. They are probably not the actual airplane but only (claimed) authentic models. It makes sense to me that the Sopwith ...
1
vote
1answer
212 views

Why does the F16 HUD give you one number for your speed and the analogue gauge another?

Why does the F16 HUD give you one number for your speed and the analogue gauge another different number?
5
votes
4answers
1k views

What are the advantages and disadvantages of tail wheels that cause modern airplanes to not use them?

Photos' source: Cessna 140 and Cessna 150. According to Wikipedia here, the Cessna 150 is successor of Cessna 140. Both have two-seat capacity and a single engine. Why was the Cessna 150 changed to ...
1
vote
1answer
143 views

Is any convention to tell the propeller rotation direction of an airplane?

Here are two airplane with single and dual engine. From single engine airplane we know there is TURN LEFT tendencies. There are four tendencies (Torque reaction, Precession, Slip Stream, and P-Factor)...
0
votes
2answers
124 views

What are the alternatives to XFLR? [closed]

So, currently my team and I are working on a glider project for our senior design. The design we've come up with causes XFLR to crash for some unknown reason (the issue seems to be at the root airfoil ...
3
votes
2answers
104 views

Did large winglets contribute to the spin behavior of the SB 13 tailless glider?

The SB-13 swept wing tailless beauty was developed in the early 1990s as a small recreational glider with relatively large upright winglets. The design proved very spin prone. It occurred to me ...
2
votes
1answer
124 views

How to calculate or design glide ratio? [duplicate]

Was interesting to watch the explanation about glider here, especially about the glide ratio. Glide ratio is defined as the ratio between altitude when it start gliding (Y-axis) to the distance it can ...
2
votes
1answer
104 views

Would a canard work better for emergency pitch down?

In order for a conventional horizontal tail plane to generate a nose pitch down effect in a stall condition, it must increase its angle of attack even more (by use of elevator or pitching up more). A ...
12
votes
1answer
562 views

Does the B-1B Lancer have controllable canards?

These three pictures shows the B-1B Lancer's canards and its elevators. I am not sure to call that feature a canard as the jet also has elevators. In my limited understanding, canard and elevator are ...
0
votes
0answers
93 views

What airfoil is used for the horizontal stabilizer of a 737? Is it inverted?

I cannot find the airfoil of the Boeing 737 horizontal stabilizer or any typical tail airfoil of a civilian aircraft.
0
votes
1answer
38 views

How to calculate on ground aircraft yaw rate knowing the longitudinal speed and inferred yaw angle

Please consider the following scenario: a generic aircraft is on-ground taxing at 50 feet per second (~15.25 m/s, ~29.5 knots) The pilot inferred 20 degrees of yaw How can I calculate the yaw rate ...
2
votes
0answers
119 views

Aeroplane protection against lightning strikes [duplicate]

I would like to know what kind of protection are available on planes against lightning strikes.
3
votes
1answer
198 views

What is the function of activating an individual elevator on the B-1B Lancer?

This B-1B Lancer's picture I captured from this Youtube video. The control axes is from Wikipedia. As we know, the three "conventional" axes are as follows: Roll axis controlled by aileron, Pitch ...
7
votes
8answers
12k views

Why don't they build airplanes from 3D printer plastic?

I'm not an expert in this field. My assumption is that there are plastics lighter and stronger than the materials used to build planes. So that would make plane lighter and thus would consume less ...
10
votes
2answers
2k views

How can an F-22 Raptor reach supersonic speeds without having supersonic inlets?

The F-22 Raptor and some other jets do not have inlet spikes, yet they are able to achieve supersonic speeds. How is that possible?
3
votes
1answer
151 views

Why does the spool speed increase with altitude for a turbofan engine (single spool & double spool)?

So, I want to see the effect of altitude on the compressor characteristic of a single spool & double spool turbofan engine at constant flight speed and TIT (turbine inlet temp). I am aware that ...
5
votes
2answers
205 views

How do splayed wingtips work?

I need to know more about the "splayed wingtips" design made by Airbus in their latest conceptual design "birds of prey". How would wingtip vortices work on this plane? How are they reduced by the ...
5
votes
1answer
152 views

What adds more weight to a twinjet? Tail-engines or wing-engines?

Let's say we have a large commercial jet, with exactly 2 engines, capable of holding at least 200 passengers. It could be a traditional jet like the Boeing 777, where both engines are in the wing. Or ...
4
votes
1answer
308 views

How to calculate ground speed using a map with a known scale and time?

If an aircraft flies from point A to B for a distance of 8cm on a chart of 1:1,000,000 in 18 minutes, What’s the ground speed? It’s a multiple choice question and the possible answers are in ratios. (...
27
votes
3answers
4k views

Is it true that different variants of the same model aircraft don't require pilot retraining?

I'm referring to this Wendover Productions video - The Economics That Made Boeing Build The 737 Max. The creator asserts that designing a new long range narrow body plane would be more expensive ...