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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53
votes
6answers
9k views

How can this aircraft be stable/manoeuvrable?

The new wave of electric VTOL aircraft concepts (Joby Aviation, Zee, Lilium, Airbus A$^3$, etc...) has produced some audacious unconventional designs. Now my question is how Lilium's concept can be ...
41
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9answers
7k views

Why was the boat mounted this way on the underside of the wing on the “Landseaire” flying yacht?

After seeing the below image of the "Landseaire" flying yacht here I was curious to know why the small boat mounted to the underside of the plane was mounted the way it was. At least to me (and @Dave ...
18
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2answers
17k views

Do helicopter rotor tips regularly go supersonic?

In my question about helicopter noise, I made the assumption that one reason they are so darn noisy is that the main rotor tips go faster than the speed of sound. @FreeMan questioned whether that was ...
1
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3answers
223 views

How many fastener can an aircraft lose?

I see this GIF animation a few times then I wonder how many fastener can an aircraft lose before it becomes dangerous. I’m sure losing one wouldn’t be an issue due to safety margin built into every ...
1
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0answers
71 views

Carpet Plots for Aircraft Sizing

Generally, Carpet Plots are constructed to find out an optimal design which will satisfy all the performance needs and is least in weight & cost. I want to know how to construct a carpet plot? I ...
24
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8answers
22k views

What is the purpose of having contra-rotating props on an aircraft?

Why do planes, like the famous XF-11 and the Tu-95, have contra-rotating props? What is their purpose? Image credit: Mike Freer / Touchdown-Aviation / Wikimedia
4
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2answers
941 views

Where can I find pictures of “endplate”?

Where can it possible to find pictures or drawings of "endplate"? (for "winglet" is much easier, but not endplate) I'm asking what's written above, after I read the following text from Raymer and I ...
1
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2answers
77 views

Where to find NACA 65-110 Airfoil?

I'm working on a research project regarding the Bell XS-1, which used the NACA 65-110 airfoil. I haven't been able to find any data on this airfoil, and I'm wondering if anyone knows where I could?
16
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2answers
5k views

What causes a run-away propeller?

I've never understood this, why can't you just idle the engine and let it slow down?
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0answers
51 views

Matlab code for Multhopp/Lifting Line methods [closed]

I'm part of a new SAE Aerodesign Team and i'm searching for a way to obtain the CL and CD coefficients of a finite wing in subsonic speed. I've tried some codes of Multhopp and Lifting Line Theory, ...
22
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6answers
6k views

What are the least powerful airplanes that ever flew?

What manned airplanes have achieved flight with the least powerful engines (no gliders!), and what was their top speed? Im sure I've heard of an airplane with an 8hp engine capable of exceeding 120 ...
-5
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2answers
99 views

Is a 3 horsepower engine powerful enough for a 100 pound ultralight? [duplicate]

I'm building an ultralight and it weighs 100 pounds empty. My only engine is 3HP. Is that good enough?
3
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2answers
181 views

Why does this plane have vapor trails coming out of wings? [duplicate]

See this video of Birmingham strong crosswinds landings: At 2.57, there is a 737-800 landing (screen shot below). One can clearly see some vapor (?) coming out of ...
6
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1answer
559 views

What is this type of aircraft?

In this picture, could anyone describe what type of aircraft and which airline it is?
0
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1answer
134 views

How can I identify the aircraft’s phase of flight in this picture?

It’s me again, can anyone explain how to know the aircraft’s phase from this picture? Is it cruising or descending if so why its flaps up?
37
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3answers
9k views

How does an aircraft form wake turbulence?

This question discusses how wake turbulence can affect planes flying in formation. It got me wondering, how do aircraft (the wings in particular) form wake turbulence to begin with? It can't be as ...
8
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1answer
361 views

Why was the tip of the B-52's vertical tail chopped off in 1959?

When Boeing switched over from the B-52F to the B-52G in 1959, they (among other changes) lopped off the top 2.4 meters (8 feet) of the aircraft's vertical tail: Original-height tail (here on a B-52F)...
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0answers
48 views

Is there any bibliography for triplane aircraft design?

I've been tasked with designing an RC aircraft that has the greatest lift force for a specified wingspan, total length and takeoff velocity, and thus have been studying the different wing ...
18
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2answers
3k views

What are the most powerful airplanes that ever flew?

This question What are the least powerful airplanes that ever flew? made me wonder what the most powerful manned airplanes are that ever flew. There are two sensible categories, I suppose: Most ...
7
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1answer
290 views

Why is 51,000 ft a common service ceiling for business jets?

According to this article on aerospace-technology.com, many of the larger business jets seem to have a service ceiling of 51,000 feet. Other sources verify this trend. What is the reason for this, if ...
2
votes
1answer
180 views

Why does the KC-46 use two sensors for MCAS when the 737 Max doesn’t?

this article states The KC-46 has a two-sensor MCAS system, which “compares the two readings,” the Air Force said. I’m aware that the 737 uses two sensors and always has, but the computer reads ...
1
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2answers
119 views

XFY-1 Vertical take-off mechanics

Hi I saw this video the other day of an XFY-1 doing a vertical take-off and landing and moving left to right while hovering. See the video Here. After watching this I had a few questions on how ...
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0answers
18 views

Where can I find wind tunnel pressure data for various airfoils?

I'm working on a simple panel method solver based on thin airfoil theory and I would like to validate my code using wind tunnel data. Is there any place where I can find pressure distribution data ...
14
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3answers
3k views

Why do modern aircraft tend to have angular tails?

In the WWII-era and earlier, many (most?) planes had rounded tails, even high-speed and high-performance fighters such as the Bf 109 K, Ta 152 (though it is more square-ish), P-38, Hawker Typhoon, and ...
25
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4answers
5k views

Why are no recent small aircraft designed to be “characteristically incapable of spinning” as the Ercoupe was?

I'm a student pilot at a flight school that primarily flies RV-12s as a trainer. We had one day that through a booking error meant that all the RV-12s were booked so we had to use their Ercoupe 415-C ...
0
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0answers
30 views

What is the effect of wing flex on wing's airfoil shape and its performance effect on wing?

There are good amount of discussion on wing flex in this forum. I am more interested in understanding the effect of flex on aerofoil shape of the wing and its impact on flight performance. Do ...
4
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2answers
198 views

What is the function of the Apache's Strap Pack?

I have recently been reading about the issues with the Apache's (AH-64) strap packs. I've read that the strap pack holds the rotor blades on to the hub. However, it appears the blade also connects ...
4
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2answers
616 views

Why the need for the MCAS on the Boeing 737 Max 8?

Was there a problem with stalling on 737 jets before the 737 Max, if not then why is MCAS needed on the 737 Max 8.If it was a problem why did Boeing wait so long.
0
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0answers
57 views

Is there a difference between blended wing body and hybrid wing body?

Internet searches for "blended wing body" and "hybrid wing body" bring up very similar designs. Is there really a technical difference and if so who lays the convention down?
19
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8answers
9k views

Double deck vs wide body airliner, why would anyone build a double deck one?

I don't understand why double deck aircraft (or multiple decks in general) are a good idea. They must be, because there is a significant amount of them. But given a cross area, which should roughly ...
1
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0answers
56 views

What's the benefit of cranked wing for commercial airplanes [duplicate]

Many commercial airplanes have a kink in the wing geometry. A discontinuous change in the wing trailing edge sweep is present in the wing of the A320. What's the benefit of this? Is there any ...
1
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1answer
129 views

Airfoil and Wing Analysis for Transonic Speed (M = 0.85 and Re = 42 million)

I am working on a project where I have to design a plane which has to cruise at 0.85 Mach at 35,000 ft. While working on the wing design, I quickly discovered that 6 series airfoils, with a good ...
1
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1answer
95 views

Does the center of mass for an airplane have to be over the wings?

I am designing a model aircraft that will have 4 propellers in a square configuration (think like a quadcopter) so that it can take off and move around like a quadcopter, then transition into plane ...
2
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2answers
75 views

How to select and electric propulsion system for my experimental Ultralight?

I've been trying to design and build, my experimental Ultralight using electric propulsion system, My plane designed base on Slaler and Gensis ultralight , following is the primary calculation Empty ...
1
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0answers
125 views

Ailerons deflection of the F16 in take off and landing gain?

Let's say you are at a safe altitude and landing gear is down and the aircraft is in To/L gains and you want to do aileron roll and apply full left (or right ) stick to do the rolling maneuver.The ...
4
votes
7answers
480 views

Was the adoption of conventional tailplanes as 'everyday aircraft' inevitable, or are there other designs that can be just as good?

I originally asked a variant of this on Worldbuilding.SE, but they didn't seem to like it. So I apologize if it's out of place even here. I ask, because I've been forming in my head an alternate ...
2
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2answers
385 views

Is there a term for the general design used in most modern fighters?

Is there a term that encompasses the overall design of modern fighters (e.g. F-15, F/A-18, F-14, Su-27, Su-30,33,35,37, Mig-29, J-11, etc.), with dual vertical stabilizers, leading edge extensions, ...
1
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1answer
122 views

Where to find information on weight breakdown for helicopters?

I would be interested in information on the weight breakdown for the different components of a helicopter. How much of the maximum gross weight is related to the airframe, engine, gearboxes, ...
0
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0answers
18 views

Should tailplanes have symmetric aerofoils? [duplicate]

Do tailplanes generally have symmetric aerofoils, or do they posses inverted aerofoils to counter the pitch up moment? Is there an advantage to the use of the symmetric aerofoil in an all moving tail? ...
2
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2answers
1k views

What is the difference between Angle of Incidence (AoI) and Angle of Attack (AoA)?

Following discussion here, I am still confused about the difference between AoI and AoA. As I read in many references and watched in many YouTube videos especially this one: 1). AoI is tje angle ...
31
votes
5answers
5k views

In the early days of flight, were there any cockpit control schemes other than the modern one?

Back in the early days, what kind of control schemes were invented for aircraft, other than the modern one? (pedals to yaw, yoke to pitch and roll). I'm only interested in control schemes that can be ...
9
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2answers
583 views

Did the Douglas SBD Dauntless have a second set of controls?

In the book Never Call me a Hero, the author mentions that there were controls in the rear seat of the Douglas SBD Dauntless. However, I don't recall ever hearing this before, though I know the TBD ...
5
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4answers
1k views

Does the tailplane have a positive/negative camber?

I've read that the tailplane produces negative lift, so does that mean it would function like an inverted wing (has negative camber)? The image below is the best illustration I could come up with. ...
9
votes
1answer
263 views

Why is TO/GA button disabled in 777 with weight on wheels or below 2 ft RA?

Recently a final report for accident of an Emirates B777-300 at Dubai on 3rd August 2016 was published. An important factor there was that when the pilot tried to recover from long landing by going ...
31
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5answers
10k views

Why Didn't the USSR Build An X-15?

In the history of aerospace engineering in the United States, the X-15 is lauded as a critical and necessary step on the path to manned spaceflight. Throttle-able chemical rocket propulsion systems, ...
1
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1answer
133 views

How does maneuvering affect radar detection of stealth aircraft?

Stealth aircraft like the F-22 and F-35 have very low radar cross sections. These planes have angles of their fuselage set-up in a way to deflect radar signals. As far as I understand another stealth ...
6
votes
2answers
540 views

The F 18 Hornet and Mig29 ailerons from the external parts of the wings go up some degrees in flight .Why?

In some parts of the flying envelope of the F 18 Hornet and Mig29 the ailerons from the external parts of the wings go up in sync . They're made to go one up one down in order to get rolls,not ...
0
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0answers
77 views

Can friction joints be certified?

I remember being told that friction cannot be considered when designing joints as the friction coefficient can change. This could happen for instance due to water being trapped inbetween components. ...
1
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0answers
113 views

What happens when an airplane is retired?

With launch of new models every few years, what happens to the older airplanes which was in service for more than decades? Where does it get stored. Who buys old airplanes? Does manufacturers buys ...
2
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3answers
224 views

How do a helicopter's cyclic and collective transfer commands to the swash plate?

I understand the function of the cyclic and collective, and I am specifically wondering if anyone has a good image/video showing the mechanism of how the flight control "mixer" works! I can't seem to ...

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