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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
7 views

Do ducted fans have a future in forward flight aircraft? Can they be made more efficient than open rotors?

I'm fascinated by how ducted fans have the ability to be more efficient than open propellers of equal diameter in vertical flight through the use of tight tolerances, lightweight duct material, proper ...
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1answer
120 views

When aircraft rolls across airport field, uses its main engines or any kind of chassis gears? [duplicate]

Taxiing, turns, approach to gates - everything is done without the loud sound of motors
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1answer
59 views

What provides a higher lift to drag ratio, a thick laminar wing or a thinner wing with a vortex generator

Recent readings have shown the benefits of "boundary layer tripping devices" or vortex generators for reducing drag and maintaining attached air flow at higher angles of attack. It seems these ...
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1answer
290 views

Why do wings prefer laminar flow if cd is lower for turbulent flows?

Can anyone please explain to me why we prefer to maintain laminar flow over wings, despite the fact that the overall coefficient of drag appears to reduce as the Reynolds Number increases? I have read ...
3
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1answer
68 views

Can surface roughing effects on an airfoil Reynolds number be quantified?

I am building balsa free flight gliders with a chord of 0.10 meters and a velocity of around 3 meters per second. This works out to a Reynolds number of around 15,000. The wings are around 1 meter ...
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50 views

HAL SARAS : What are your thoughts on this ? [AS A CIVIL AIRCRAFT ] [closed]

Well, What do you think about it ? CAN THIS BE USED AS A CIVIL AIRCRAFT FOR PERSONAL USE ? ** ...
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5answers
7k views

Could the principle of owls' silent flight be used for stealth aircraft?

I was wondering about the ability of owls to fly so silently. Is it because they flap gently, they flap less often or do is their structure responsible? I was thinking their principle of stalking can ...
2
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1answer
103 views

What angle are front rotors of tandem helicopters tilted and why this value?

I've read that the front rotor of tandem helicopters are tilted forward so that you can get a forward velocity with no nose-down pitching of the fuselage, but what angle is used for this tilt and why ...
3
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1answer
106 views

Is there a minimal legal ground clearance to use an international airport?

The question arises while I was looking at the evolution of the B737 engines and the lower and lower space available between ground and engines. Then I realized that ground clearance is also low for ...
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2answers
137 views

Why did the DC-3 have a much higher cruise speed than the HP.42, despite their similar weight and power?

A review of the classic DC-3 and the Handley Page HP.42 yielded a surprisingly close match in empty and max gross take off weight at around 18,000 and 28,000 lbs for the HP.42 and 16,000 lbs and 25,...
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0answers
155 views

If an fighter jet that it have twin rudders, in use the angle of deployment it is not identical. Which is more deflected and why?

If an aircraft have two vertical tails then pilot push in the rudder pedal the rudders will not be deployed at the same angle.It is used throughout the all envelope of flight or is it possible only ...
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1answer
132 views

What's the aisle width of long range business jet?

What's the average aisle width for long range business jet such as Gulfstream G500?
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3answers
6k views

How are Aircraft Noses Designed?

Look at the Learjet, Embraer and Boeing noses which are kinda pointy - drag efficiency aside, how do they come to the final design of the nose? I’m talking from an aesthetic point of view - how do ...
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3answers
209 views

Why the pitch control of helicopter is named Collective Control? And why does it located at the left side of the pilot seat?

This is probably a very trivial for some of you. But sometimes a name not representing the function become a question, just like this Collective Control, which its function is to pitch up the blade ...
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1answer
531 views

What is the purpose of these movable panels on the MiG-35?

The MiG-35 has movable panels on the LERX (leading edge root extensions). There are a number of images around the web showing these panels deployed during slow flight and retracted otherwise. When do ...
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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.
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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 ...
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0answers
50 views

Does the F-16 Alt. Flap switch lock the leading edge flaps in place in an emergency?

The Alt. Flap switch is useful for the interception of slower aircraft (Cessnas, Diamonds, etc) at speeds around 145 knots but at the same time you'd have only half of the F16 roll and sluggish gains.
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1answer
237 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
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1answer
91 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
446 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 ...
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72 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?
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1answer
106 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?
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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)?
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1answer
203 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? ?
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2answers
187 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?
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2answers
112 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, ...
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2answers
548 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?
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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??
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66 views

What’s the pipe behind the F-14 fighter? [duplicate]

What’s the purpose of that pipe?what does it do?
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1answer
52 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
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1answer
271 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?
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2answers
179 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 ...
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151 views

Does the F-35's stealth coat bubble at high speeds?

Is it true that the US Air Force stipulates short supersonic bursts for the F-35 because even 3 minutes at Mach 1.3 can cause stealth coating bubbling?
2
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1answer
367 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?
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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
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1answer
156 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 ...
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2answers
303 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
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2answers
134 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
154 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 ...
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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?
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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.
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1answer
45 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 ...
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0answers
80 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 ...
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2answers
82 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 ...
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2answers
137 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 ...
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1answer
137 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
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0answers
100 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 ...
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1answer
209 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?