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
51 views

What Is This in The Top of IL-86VKP?

What Is This in The Top of IL-86VKP?
-3
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0answers
43 views

What would a NACA 69420 airfoil look like? [closed]

Somewhere around last year I was on r/aviation (or which subreddit?) where someone posted a picture of a T-shirt with a picture of the 4 forces of an airplane; Lift, Drag, Thrust and Gravity. Someone ...
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2answers
92 views

How do aircraft manufacturers determine the elevator size?

I’ve heard some pilots say the MD-11 (I think?)was made with too much elevator, and that it’s an overkill. So now I’m curious, how do they determine the length for the elevator? Is it possible to ...
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2answers
154 views

What is the maximum height for deploying a parachute? [closed]

i see a detachable plane cabin project .When an airplane crashes, the human toll is generally heavy. Based on this observation, Vladimir Tatarenko, a Ukrainian engineer who worked in particular for ...
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2answers
101 views

How to increase payload capacity of plane?

Keeping thrust , wing span , weight (of plane ) constant , can we increase the payload capacity (nearly 50% more) ? Adding payload to plane , it decreases thrust/weight ratio , how does it affect the ...
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5answers
168 views

Can lift be increased by increasing the angle of incidence of the wing? [closed]

Can the lift of a plane be increased by increasing the Angle of Incidence (angle between the chord line of the main wing and the axis of the fuselage)? Meaning, can more lift be generated while the ...
3
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2answers
165 views

Why there are two red lines on G meter reading on theMig29 aircraft?

Why there are two red lines on G meter reading on theMig29 aircraft? One at 7.5G,another one is at 9G.Also on the AOA scale the red line is at only 15 degrees .That is max AOA. Its looks like the very ...
4
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1answer
603 views

Why do all fifth generation fighters (J20, F22, SU57) put their wing above the fuselage?

I heard that upper wing could increase stability, but why do fighters need it? Or are there some other reasons? Please specify.
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1answer
169 views

What is the effect of a taildragger on P-factor?

By looking an image of P-40 Warhawk with taildragger (and other vintage warplanes), one can conspicuously find the propeller disc of this aircraft isn't perpendicular to the relative airflow which ...
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3answers
234 views

Are there a toilet and (small) kitchen in the Su-34?

It seems that there are a toilet and small kitchen in the Su-34. The Su-34 is a medium range fighter-bomber with a range of action of 4000km able to transport 8 tons of bombs and missile. I know that ...
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4answers
5k views

How do “tip jet” helicopters cancel the torque effect of the main rotor?

Some helicopters use "tip jet" on the rotor blades tips such as the McDonnell XH-20 Little Henry and Hiller YH-32 Hornet. How do they cancel the rotor torque (often canceled by the tail rotor)?
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0answers
83 views

How do I reinforce a tubular spar that has been drilled vertically for an attachment bolt?

Previously posted a question about lift strut attachment to tubular wing spar with a bolt vertically through the spars. See drawing below. I tried using Bruhn's analysis book to formulate a a ...
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1answer
320 views

Why do all fifth generation fighters (J20, F22, SU57) use Trapezoid wings?

It seems that trapezoid wings are used by all fifth generation fighters (although the wing of J20 looks quite like delta wing), but why? What made a trapezoid wing so attractive? Why don't they use ...
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2answers
142 views

Does joystick position control bank angle in some Airbus aircraft? And what happens when the pilot deflects the joystick when wheels are on ground?

Does joystick position control bank angle rather than directly controlling aileron/spoileron deflection in some Airbus aircraft? Also, what happens when the pilot deflects the joystick when the all ...
51
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1answer
5k views

Why are engines angled toward the fuselage?

Source: twitter.com I saw a picture of a 777 from overhead and I was wondering why the engines point "in" to the fuselage, rather than being parallel to the fuselage.
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3answers
191 views

Does the Prandtl flying wing have a lower maximum speed than other designs?

Does the design of the wing with its "twist" near the wingtips necessarily limit the maximum speed of an aircraft utilising that technology? Also, with the leading edge profile/attack angle varying ...
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1answer
54 views

Which Velocity is used to measure Dynamic Pressure?

Suppose an airplane is flying in windy conditions. Now, for the calculation of the dynamic pressure should I use the relative velocity or the absolute velocity as the free stream airspeed?
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1answer
7k views

Why does the Pratt & Whitney 747 have an extra engine on the right side but not left side? [duplicate]

What’s the purpose of this design, and why only on one side?
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0answers
113 views

How is roll control achieved for the space ship two?

When looking at scaled composite 339 space ship two I fail to see control surfaces on the trailing edge of the wing. For me, it seems that the only moving surface on the wing is the feathering ...
5
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1answer
197 views

Why are crop dusting spray booms not integrated into the wing?

All crop dusting aircraft seem to have an externally mounted spray boom for distributing their pesticides, I imagine this significantly increases drag & therefor performance. What gives? why not ...
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0answers
47 views

Where can I find full range polars for a section?

In this post I found the full alpha range polar of NACA0012 Is there an aerofoil that gives reasonably good lift for both air flow directions: forward and backward? I found a graph for Cl and for Cd, ...
2
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3answers
284 views

Is it possible to use refrigeration technology to cool the skin of supersonic aircraft?

The fastest air breathing aircraft, the Blackbird SR71 flew at speeds above Mach 3. Its engines could achieve much higher speeds but were limited by the aircraft's skin which would melt due to ...
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0answers
76 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 ...
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3answers
233 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 ...
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2answers
91 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?
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2answers
113 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
196 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 ...
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1answer
140 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?
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0answers
51 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 ...
7
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1answer
304 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 ...
6
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1answer
584 views

What is this type of aircraft?

In this picture, could anyone describe what type of aircraft and which airline it is?
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0answers
19 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 ...
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2answers
125 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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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 ...
2
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1answer
201 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 ...
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0answers
36 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 ...
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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 ...
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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 ...
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 ...
4
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2answers
209 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 ...
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0answers
60 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?
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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 ...
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1answer
96 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 ...
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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 ...
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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? ...
1
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1answer
137 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 ...
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2answers
78 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 ...
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0answers
128 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 ...
9
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1answer
291 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 ...
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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. ...

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