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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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0answers
13 views

Yoke-Stabilizer Design Negligence [on hold]

Gentlemen, Thanks for your support with the 2 answers above. The Boeing 737-Max appears to be the first plane in aircraft history to have conditional pitch control (sometimes it works, sometimes it ...
1
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1answer
110 views

Who should design the nozzle of jet engines on aircraft?

There is a question in my mind that which company should design the nozzle of jet engine - the aircraft designer or the engine designer? If you watch this documentary: BBC Documentary Rolls Royce ...
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2answers
101 views

Is the Meredith effect utilized in the cowling design of air-cooled engines?

The P-51 is famous for its advanced-for-its-time aerodynamics, the prime example of which is the radiator design under the belly which utilizes the Meredith effect to, in effect, turn it into a mini ...
6
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4answers
141 views

Why do carburetors tend to produce richer mixture at higher altitude?

The pressure drop in the venturi is proportional to air density and the fuel is at ambient pressure in the float chamber, so I would expect the fuel flow to reduce proportionally with density, and ...
2
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0answers
73 views

If a twin-engine airplane's propellers both rotate in the same direction, do they still produce a left-turning tendency?

If an airplane with two propellers has both propellers with the same rotation direction (say, both the propellers rotate counter-clockwise as seen from nose to the tail), will be the four left-...
9
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1answer
2k views

Do rivets on airframe need special sealant to be airtight on pressurized airliners?

Do rivets on airframe need a dedicated sealant, e.g. epoxy, to be really airtight on a pressurized airliner, or is the expansion of the rivet shaft already sufficient? As a side note, how are carbon ...
5
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1answer
313 views

Why Western fighters' afterburner glow is reddish orange while Eastern Bloc fighters' is blue?

Recalling what little physics I know, this could be explained by two factors: The blue color is given by the characteristic EM radiation of C-H bond breaking, C- and H- radicals forming and ...
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1answer
50 views

What airfoil type is used on the B727-200F?

What airfoil type is used on the Boeing 727-200F? Is it a NACA profile or something else?
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1answer
115 views

Why is YF22 designed with conventional rudders while YF23 with all-moving rudders?

Are all-moving rudders more stealthy? If so, how come YF22 which is just as fixated with rear body stealthiness as the YF23 comes with conventional ones? Also, all-moving rudders have fixed camber, ...
9
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1answer
168 views

How do flaps deploy and stow with very large wing flex?

On large airliners, the wings are generally of the high aspect ratio types and hence very flexible. Now the flaps are attached to wing only through a series of tracks, and as the wings flex, these ...
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0answers
42 views

How can I calculate the lift generated by a specific wing? [on hold]

What will be the amount of lift generated by a wing if it has a total surface area of 6m2 and it is moving with the velocity of 50km/h? And the airfoil has a flat bottom shape.
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2answers
148 views

How do you use a flexible drive shaft?

Saw it on a 747 freighter nose door, see it again on an F16's M61A1 gun assembly. How do you design with a flexible shaft? In what situation do you use it to replace a bunch of rigid shafts and gears?...
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1answer
138 views

What percentage or airplanes have engines [closed]

I heard that some airplanes don't have engines. how many airplanes in the world have engines?
4
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1answer
102 views

Can roll be controlled through elevators in a fixed-wing aircraft? [duplicate]

In fixed-wing aircraft, roll is typically controlled through ailerons. But I am wondering if roll could also be controlled through split, independently controllable left/right elevators?
4
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3answers
231 views

Do large non-pressurized metal planes have a maximum fatigue cycle?

For example the DC3. The way I understand it, the only thing that "ages" the airframes of DC3 is the landing/takeoff cycles and the accompanied periodic force loading/unloading. Do planes such as this ...
3
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4answers
177 views

What changes are needed for a piston-prop aircraft to withstand saltwater environment?

I'm interested in WW2-era piston-prop aircraft. I want to know what changes are needed to make the aircraft withstand saltwater corrosion. Presumably these are different and more expensive than the ...
0
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1answer
91 views

Fuel De-aerating Tank?

I know turbine engines (bearings) are cooled by oil jets and that when oil is scavenged from the bearings it is more of a mist than a liquid, hence the need for various types of de-aerating this mist ...
0
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1answer
29 views

What to be considered in designing airplane tail (vertical and horizontal stabilizer, elevators and rudder)? [closed]

I would like to make a small amateur triplane with it maximum weight approximately 400 kgs with maximum speed 100 knots (180 kph). I have read many discussions about how to calculate the wing ...
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0answers
54 views

Why does the Comet's horizontal stabilizer have so much dihedral?

The Comet's horizontal tail has a noticeably extreme amount of dihedral compared to that of, say, a 707: (Image by MilborneOne at Wikimedia Commons.) Note how the Comet's tail has about twice as ...
0
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4answers
134 views

Why some WWII fighters still have fabric/wood control surfaces?

I've heard people say that the reason US in WWII preferred designs with fabric control surfaces with either a metal or plywood frame is they can sustain some small arms fire without disintegrating. Is ...
11
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3answers
380 views

Do fighter jets have deicing in their wings?

If there is such thing as deicing for fighters? If so, is bleed air or electric heating preferred? I could not imagine that a $50MLN fighter jet would not be able to get the ice off its wings.
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4answers
183 views

How is vertical speed managed in Airliners? [duplicate]

When an Airplane starts to take off, the Horizontal velocity would generate it the necessary lift, and then Airplane pitches up to further increase the lift. As the Airplane is climbing up, the net ...
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2answers
186 views

Boeing 737-MAX Control System Design Flaw? [closed]

I’m concerned about Boeing aircraft safety design flaws because it is so disturbing to see so many lives lost in aircraft accidents. I’ve attempted to contact Boeing about this. But officially they ...
3
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2answers
256 views

Can an Airbus A380 or Boeing B747 fly with only 2 engines?

If during cruising with full load, these two kinds of airplane got two of their engines failure: With one engines fails in each side (so, only one engine works every side). With 2 engines fail in one ...
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1answer
283 views

What is the purpose of this item next to the cockpit window on the B737?

Hello does anybody know what the purpose of this odd looking shape is
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3answers
340 views

Is the MD-11's third engine slightly nose up?

From my visual inspection, the third engine (the engine on the horizontal stabilizer) is slightly "nose up", especially compared to the engines on the wing. That means, the front part of the engine is ...
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1answer
44 views

Difference between FMCF and AIMS on B777?

What is the Difference between Flight Management Computing Function and Airplane Information Management System on B777?
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1answer
123 views

Where can I find complete aircraft blueprints for the purpose of study?

Where can I find aircraft blueprints for the purpose of study? I find that I learn a lot more when I am able to get the big picture of a machine that is used in real life (for example, to understand ...
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1answer
198 views

Boeing 737-MAX stabilizer control

Various websites have stated that during the 737-MAX crash in Indonesia, the pilots could not pitch up because of a faulty AOA sensor pitching plane down. Stabilizer has a rear fulcrum and front jack ...
4
votes
2answers
155 views

Why the Antonov AN-225 has negative dihedral wings combined with a positive dihedral horizontal stabilizer?

I know the reason why it has negative dihedral wings, but I do not really know why it is combined with a positive dihedral horizontal stabilzer, which are the benefits this configuration provides?
10
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5answers
3k views

Why didn't Boeing or Douglas make a jet airliner before the British DH Comet?

I was looking at the history of commercial aircraft and was wondering why UK-based De Havilland was the first to produce a jet powered airliner (the DH 106 Comet) when the US had a much bigger civil ...
4
votes
2answers
349 views

What is this unusual leading edge flap on a B737-200?

On this video of Air North's gravel runway-equipped B737-200, there's what appears to be a small leading-edge flap (Krueger flap?) inboard of the engine. Refer to the screen shot below. What is this?...
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1answer
57 views

Where should the support points be for testing a model wing in a wind tunnel?

When testing a certain wing profile inside a wind tunnel where should the model, small scale wing be supported? Should the support be under the center of mass of the wing or under the aerodynamic ...
2
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4answers
208 views

Why are the leading edges of wings not always made as 'sharp' as possible?

Why is an airplane's wing (the leading edge) not made as sharp as possible to break the air, in the same way that a ship's hull is made sharp to easily break the water? This is unlike Concorde's nose ...
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2answers
80 views

Would a sharper leading edge increase lift and reduce drag at lower speeds?

A recent scratch built glider kept turning to the right even after painstaking efforts to match the wings perfectly. Extensive addition of fin area to the tail failed to correct it. Closer ...
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0answers
35 views

How could I measure frontal area based on a technical drawing?

I want to compare frontal surface areas of two airplanes, and I have their digital technical drawings and wingspan data. What program could I use to obtain the surface area using this data? Esentially ...
0
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2answers
111 views

In an airplane wing, which one is primary, and which one is secondary

I got this device detail of a wing. Those parts are: 1: wingtip fence, one of the wingtip device beside winglet. 2 & 3: aileron. 4: flap track. 5 & 6: slat. 7 & 8: flap. 9 & 10: ...
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1answer
47 views

How do we derive Lift Coefficient of an airplane's wing?

In many references I read that lift coefficient ($C_l$) is a product of wind tunnel test. But many times I read the formula to calculate the coefficient of lift. From the lift equation, $$L=\frac{1}{2}...
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0answers
42 views

How many variations are there of the Avro Lancaster?

How many different variations of the Avro Lancaster are there?
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2answers
83 views

How do endplates reduce induced drag?

I have heard the explanation which states that the endplates reduce the tip vortex formation thereby reducing induced drag. From what I understand induced drag is the backwards component of the total ...
3
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3answers
308 views

Why did narrowbody jetliners take so long to switch over to high-bypass engines?

High-bypass turbofans were introduced into the airliner market around 1970, when the first widebody jetliners were released (the 747 was first, followed in rapid succession by the DC-10, L-1011, and ...
1
vote
1answer
80 views

What was the Airfoil of Handley Page P.115?

This extreme sweptback delta was built to test the Concorde wing at low speeds, sources say it had a biconv 6% airfoil, but I failed in finding data about it.
16
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3answers
7k views

Why has the 777x been designed with folding wingtips?

I recently visited the Boeing factory outside Seattle, WA and noted in the distance a new 777x being built with, what looked like very large wingtips. However, on closer inspection they're not - the ...
11
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4answers
3k views

Why isn't there a single best airfoil for subsonic flight?

Why does airfoil used by modern subsonic aircraft (this is true for transonic airliners too) vary from plane to plane? Haven't we figured out a single best airfoil shape, with the highest lift to ...
7
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4answers
438 views

Why do cargo aircraft still have floors?

Even with dedicated cargo aircraft built as cargo aircraft (rather than converted from a passenger-carrying configuration), the cabin is virtually always still divided into an upper and a lower lobe (...
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1answer
52 views

What is the wing span in aspect ratio's calculation?

We all know that the aspect ratio of an airplane is calculate as: $$AR=\frac{b^2}{S}$$ Where: $AR=$ Aspect ratio $B=$ Wingspan $S=$ Wing's area In an airplane, wing span is the distance from tip ...
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4answers
166 views

How does Bernoulli's principle contribute in lifting airplane?

I have searched if any explanation that bind Bernoulli's principle in lifting airplane. There is one here which receive many appreciations, but still did not answer the question. So far, it was taught,...
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2answers
70 views

Since speed is related to dynamic pressure, then why is static pressure used instead of dynamic pressure in ASI to measure speed?

Since speed is related to dynamic pressure, then why is static pressure used instead of dynamic pressure in ASI to measure speed? Why is dynamic (or pitot) pressure not sufficient?
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3answers
137 views

What makes an airplane can take off very short?

I watch STOL pilot champs Zenith CH701 here. The engine power are: 130HP, 80HP, 120, and 100HP respectively. Amazing. As per my observation, the third airplane take off shorter than it length. It uses ...
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0answers
14 views

What is a typical Cd0 value for single-slotted flaps?

I've been having trouble finding any source for what a typical value would be for single-slotted flaps. I haven't been able to find any information within Anderson's Aircraft Performance and Design or ...