Questions tagged [aircraft-design]

Questions about the different choices that aircraft designers (typically aerospace engineers) make in order to create an aircraft.

Filter by
Sorted by
Tagged with
31
votes
2answers
12k views

What is the purpose of the “Mirror-Thing” over the Mig-29 Cockpit?

I noticed that some Mig-29 Fighter Jets have a little mirror-like-thing over the cockpit. I can't imagine a possible usage from it (If it's really a mirror). Here's a picture from Wikipedia: As ...
31
votes
3answers
4k views

Is it safe to roll an airplane that isn't approved for it?

I have heard of pilots rolling airplanes that aren't approved for it (Cessna 172, Learjets, etc.), and other than the obvious legal issues, are there any mechanical or safety reasons to avoid it? ...
31
votes
2answers
21k views

What is this on top of the Air Force One?

Clarification: It wasn't Air Force One that visited Switzerland, it was the 747-200 E4 carrying Ashton Carter. Source What is this thing on top of the plane (In red circle): On other "Air Force One" ...
31
votes
4answers
6k views

Why does the B-2 have a smaller payload than other bombers of comparable size?

B-2 Spirit1 Payload 40,000 pounds (18,144 kilograms) Wingspan 172 feet (52.12 meters) Weight 160,000 pounds (72,575 kilograms) Maximum takeoff weight 336,500 pounds (152,634 kilograms) Range ...
31
votes
3answers
14k views

Why do some aircraft have multiple ailerons per wing?

In a recent flight on an Airbus A380 I noticed that its ailerons are split into three segments which move independently. What advantages does this design have? Do other aircraft have split ailerons (...
30
votes
6answers
9k 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
30
votes
6answers
4k views

Would an 8% reduction in drag outweigh the weight addition from this custom CFD-tested winglet?

I'm writing an essay at school about why there is so much variation in winglet design. I am analysing all the primary types of winglets used today in the aviation industry. I'm constructing them in ...
30
votes
5answers
5k views

How “over-engineered” were old planes and how “over-engineered” are they now that we have more advanced testing and research options?

I've seen several times on shows on television, and even talking to older pilots, where they will tell me that old planes were "over-engineered" to add some margin for errors on the designed ...
30
votes
5answers
49k views

Why does the 747 have 4 engines instead of 2?

If the 747 can fly with two engines, why does it have four engines? What is gained by adding another 2 engines? Flights over the ocean? Fuel savings? Safety?
30
votes
4answers
8k views

What is this line found above the door on many aircraft?

Many aircraft have this line above the door as seen in the photos below. What is it, and what is its purpose? Source Source
30
votes
1answer
11k views

What is this “No Hand Hold” thing in the P-51 Mustang cockpit?

Does Anybody remember Combat Flight Simulator WW2 Europe Series ? In the P-51, there is a "something" with "No hand hold" text on top of it What is that ? Image source
30
votes
4answers
49k views

What materials are plane windows made of?

I've always wondered, what are those dual-layered (bonus: sometimes they have a little <2mm hole, why is it there?) windows commercial jets put next to their seats made of?
30
votes
1answer
27k views

Why is there a hole in one of the layer of an airplane's windows?

On a commercial airliner, there is a hole in one of the layer of the passenger windows. See here: and here: Or in more detail: Can you explain the physical reasons for this design choice?
29
votes
8answers
5k views

Could there ever be a fully solar powered airliner capable of transatlantic flights?

Could a new or a modified existing airliner, e.g., a Boeing 737, be fully powered by solar energy and make the normal length trips aviation-fuel powered aircraft make?
29
votes
4answers
8k views

Why are most weapons in AC-130 on the left-hand side?

Lockheed AC-130 gunship is a heavily armed ground-attack aircraft variant of the C-130 Hercules transporter. The plane is manufactured by Lockheed and converted by Boeing. Why are most of the guns in ...
29
votes
2answers
31k views

How can a helicopter be designed without a tail rotor?

How will the main rotor torque be balanced if a helicopter doesn't have a tail rotor?
29
votes
3answers
9k views

Why is the most common hydraulic fluid so poisonous?

The usual hydraulic fluid, Skydrol, is poisonous. If it makes it to the air conditioning system, it causes fume events that may have adverse health effects up to and including at least one fatality. ...
29
votes
3answers
9k 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-...
29
votes
3answers
6k views

Do some airplanes have weighing scales on the landing gear?

It seems to me that takeoff weight is an important piece of data, and if one had weighing scales between the wheels and the aircraft body, one could precisely determine it. However, searching the ...
29
votes
3answers
10k views

Aircraft pilot's seats: what is the notch for?

If you do a Google or Bing search for "Aircraft Pilot Seat" then choose images, you might notice a large number, perhaps majority of them, have a notch cut out of the front of the seat. What is this ...
29
votes
4answers
31k views

How do conventional and T-tails differ?

What design considerations go into the decision between conventional tails and T-tails? Functionally the horizontal stabilizer/stabilator are the same in both cases, providing negative lift, the ...
29
votes
1answer
9k views

Why are most cockpits gray?

Russian cockpits were often painted turquoise to reduce pilot fatigue. So my question is why most non-Russian cockpits are painted gray, or in the 777's case, tan?
28
votes
3answers
11k views

Can cameras and LCD screens replace cabin windows?

Windows in aircraft create a weakness to the structure, that is why they are very small. I'm not asking about installing them in the cockpit, which would create safety pitfalls, but could the windows ...
28
votes
8answers
13k views

Is there a good reason why modern airliners can't have conventional landing gears (vs. tricycle landing gears)?

By "good reason", I mean a reason that we definitely cannot overcome with reasonable changes in aircraft design, control laws or procedures. As possible benefits of this I see a much smaller (= ...
28
votes
11answers
15k 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 ...
28
votes
2answers
11k views

What helicopter has the most rotor blades?

I have seen 2 rotor blades up to many and wonder when does having more rotor blades become less efficient? What helicopter has the most rotor blades? Related: Why don't helicopters prefer shorter ...
28
votes
6answers
6k views

What is the smallest manned aircraft with four engines?

What is the smallest (by operating empty mass) quad-engine aircraft that satisfies these conditions? Current or past airplane aircraft with fixed wings, not a rotorcraft, not a lighter than air, etc ...
28
votes
3answers
36k views

What causes a plane's wing tips to leave a small white vapor trail?

What is the source for what looks to be small trails of smoke or condensation sometimes coming from the very tips of a jet aircrafts wing tips?
28
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 than ...
28
votes
5answers
12k views

Why do we use pylons to mount the engines on jetliners?

This question focus on jet airliners. The De Havilland Comet's engine were mounted inside the wing, the Concorde's engines were mounted underwing (as many jet engines) but without pylon. It seems jet ...
28
votes
6answers
24k views

How thick is the skin of an aircraft like the Airbus A350 or Boeing B777?

We can evaluate how thick walls are by looking at door or window frames, however that isn't representative of an aircraft fuselage, which appears to be very thin: Airbus A350 XWB forward fuselage, ...
28
votes
6answers
6k views

What is this F-18 Hornet “air intake” for?

I think I read once that they served to cool the on-board computer systems, but I'm not sure.
27
votes
10answers
7k views

Is there an aviation career where I would help design an entire aircraft and its systems?

If I want to design and build planes, what career would that be? Would it be a mechanical engineer, systems engineer, or what else. (I feel like saying aerospace engineer is too vague and most ...
27
votes
10answers
44k views

Can a plane fly without the Vertical Stabilizer?

What would happen if a plane (for the sake of the question let's say that the plane is an Airbus A380) lose its Vertical Stabilizer?
27
votes
3answers
10k views

Why don't we see business jets with wingtip fuel tanks anymore?

There is something I miss from the Learjet 35 (one from FS95/98) that I don't see any more: Fuel tanks on the wingtips! What happened to the wingtip integrated fuel tanks in the business jet industry?
27
votes
6answers
8k views

Why use an airplane with non-retractable landing gear for aerobatics?

I'm watching footage from Red Bull Air Race 2017 in Kazan (one example is ) and clearly at least some of the airplanes used have non-retractable landing gear. I was ...
27
votes
9answers
104k views

Why do some fighter jets have two pilots while others have only one?

Why do some fighter jets have two pilots, while some have only one? For example the newer fighter jets such as Dassault Rafale, Eurofighter typhoon etc. are mostly with single-seat, but two-seat ...
27
votes
3answers
9k views

Would the Gee Bee be allowed to fly today, with so little forward visibility?

When looking at the Gee Bee: Source I wonder what the pilot is actually able to see, when rolling on the runway, when flying level, or trying to locate a possible emergency landing place. It seems ...
27
votes
6answers
7k views

At what speeds can an airplane land?

I have read people's stories that they landed their small planes (e.g. C172) on bigger airports. They strongly recommended landing at a higher speed and without flaps as the runways are quite long, ...
27
votes
2answers
31k views

What are the advantages of more than 4 propeller blades?

I have heard that propellers with more than four blades are not as efficient as 4 or less blades because of lower thrust which may result from interfering prop-streams. But I see the ATR-42/72 and ...
27
votes
5answers
8k views

Is this a wing-tip device on the A-10 “Warthog”?

Source: Flickr courtesy of: U.S. Air Forces Central Public Affairs, photo by Master Sgt. William Greer Notice at the side edges, the wing peels down and back around towards the fuselage. (The ...
27
votes
3answers
5k views

Why does the DC-10's horizontal stabilizer have such a pronounced dihedral?

If you look at this picture, you'll see that the horizontal stabilizer has a very pronounced dihedral in comparison to the wings. Could somebody explain in a simple way why? I understand that a ...
26
votes
4answers
15k views

What is the reasoning behind using depleted uranium as counterweights in the 747?

I recently found out that some of the earlier models of 747 had between 600 and 1100lbs of depleted uranium as counterweights. These counterweights were found in 747s manufactured between 1968 and ...
26
votes
5answers
9k views

How does an aircraft tailplane work?

How does an aircraft tailplane keep the aircraft stable, and prevent it from tipping over? Also, how does the lift generated by a tailplane compare to that generated by the wing?
26
votes
3answers
11k views

Why are the throttles of aircraft such as the Twin Otter placed on the overhead panel?

Some aircraft such as the DHC-6 Twin Otter, have their throttles on the overhead panel: Is there a reason that they are not on a center console between the pilot seats or mounted to the panel like on ...
26
votes
5answers
22k views

Could a pilot incapacitate other crew/passengers by manipulating cabin air quality/pressure?

Could a pilot of an airliner incapacitate everyone outside the cockpit by somehow triggering a loss of cabin pressure while simultaneously disarming the airplane's oxygen masks, manipulating the air ...
26
votes
2answers
7k views

Is it possible to fly with counterbalanced single blade engines?

Refer the image for counterbalanced single blade (Source http://www.aviastar.org/helicopters_eng/bo-103.php). In ground school, they took us for aircraft inspection at end of our ground school ...
26
votes
2answers
18k views

How much force does a 747 land with?

I've been told before that the runways for large commercial aircraft have to be built to withstand a large amount of force. But I'm wondering exactly how much it is? When a 747 touches down, how ...
26
votes
3answers
3k views

Is wingtip design mature?

There are many wingtip design, all made to reduce vortex related drag, and neither boeing nor airbus seems to prefer one over another. They move from one design to another at each new aircraft, always ...
26
votes
1answer
3k views

What is the purpose of the extremely high cabin altitudes in military aircraft?

The Lockheed SR-71 and the (old) Lockheed U-2 were engineered to maintain cabin altitudes in excess of 25000 feet AMSL at an altitude of more than 70000 feet AMSL. However, in both airplanes, pilots ...

1 2
3
4 5
46