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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1answer
74 views

How could Airbus better tailor the A380 to the modern market? [closed]

I understand any company do things that give net profit. But, had not manufacturing newer engines that increase its Endurance and Range saved it from its decline? Airbus had designed the A380 to ...
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1answer
63 views

Can a normally poorly handling airframe with high moments of inertia actually have superior flight dynamics under autonomous control? [closed]

I’m not a pilot but know a thing or two about flight dynamics. As you know there are currently quite a few aircraft under development designed for low-and-slow and (eventually) autonomous flight. ...
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1answer
106 views

Would mid-air refueling for an air-to-space vehicle that flies like a plane be a viable advantage if the tech was available? [closed]

Let's take the style of an F-22 Raptor (awesome!), build the fuselage, wings, etc to handle runway takeoff horizontally and then vertically (if needed) up to orbital space flight to reach the ISS in ...
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1answer
138 views

Why does the Cessna 208 Amphibian have extra tail surfaces?

Mark Harkin, CC BY 2.0, via Wikimedia Commons I've seen extra tail surfaces that look like additional vertical stabilizers on the C208 Amphibian. Why is there a need for this? I can't imagine that ...
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10 views

How OK or not OK is it to consequently delete correct answers [migrated]

I couldn't help noticing a small group of players very consequently deletes all my answers, leaving questions with heavily biased answers only. Aside from it being annoying to have players launch ...
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1answer
92 views

Why does the Information Manual say “C172S - Flaps 10 (Preferred) for Normal Takeoff”, when the models before S-model do not have this note?

Do Flaps 10 really do anything performance-wise other than reducing ground roll and distance over a 50-foot obstacle? If not worried about clearing an obstacle, does a Flaps UP-normal takeoff make ...
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2answers
88 views

Why is a reciprocating engine air intake a reverse bell shape? [duplicate]

Why would this inlet for the induction system get wider as the air approaches the filter? What net effect does this have on intake pressure, and how would an inlet that starts wide and then narrows ...
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2answers
895 views

Would fitting a T-tail on the 737 Max make MCAS unnecessary?

This is pretty far out, so I just pose it as a question for notion or ideas, rather than conclusive answers. Considering the differences in flight characteristics between the Boeing 737 Max-8 and ...
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2answers
95 views

Airplane Parachute [duplicate]

I want to ask two questions. Why don't they have parachutes on a passenger airplane? Could it be possible to have a parachute designed for their airplane? Like a big parachute that can safe the ...
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3answers
190 views

How heavy are modern cantilever monoplane wings?

Aircraft need to reduce weight in order to reduce induced drag. The modern shallow cantilever beam wings carry a massive weight penalty, as most of the material is wasted inefficiency absorbing the ...
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4answers
2k views

Were leading edge ailerons tested?

So far I have never come across any testing being done on having the ailerons and/or elevators on the leading edge of a wing, rather than on the trailing edge. Does anyone know of such tests existing? ...
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1answer
57 views

What is the correct definition of “spanwise” and “chordwise” with a swept wing?

What is the correct definition of "spanwise" and "chordwise" with a swept wing? For example, in the context of "spanwise airflow" and "chordwise airflow"? a) ...
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1answer
137 views

Is there a better solution than the U-shaped tailplane for this Airbus concept?

Image source: airbus.com This U-Shaped tail is from a concept aircraft from Airbus, I was wondering if there is an alternative but just as good solution to the U-shaped tail. Using a canard in the ...
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1answer
153 views

Can a single seater airplane fly with 50 lbs of thrust

An airplane with 10 sq meters of wing five meters fuselage and including one person. can it fly with 50 lbs of thrust? And the max weight is 400 lbs
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0answers
17 views

For a supersonic inlet, does an increase in Mach number lead to an increase in adverse pressure gradients?

For a supersonic inlet, does an increase in Mach number lead to an increase in adverse pressure gradients because of the shock waves(which leads to boundary layer separations) and decrease in inlet ...
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2answers
3k views

Why do the engine nacelles on the P2V Neptune extend so far back?

I was studying a picture of a P2V Neptune seen from below, and what struck me was how far back the engine nacelles reach. Unfortunately, I can't find that original photo but this one shows what I'm ...
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3answers
246 views

Would a flying-wing drone fly farther if filled with helium?

I'm wanting to build a flying wing designed drone and I'm wondering if I were to fill the fuselage with helium if it would improve it's range.
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3answers
257 views

Why do X-wing configurations missile/guide bombs use symmetric airfoils?

From all the missiles/guide bombs I have come across, I've always observed that a symmetric airfoil is used for both the wing and tail. Why not have a cambered airfoil for the wing and a symmetric ...
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1answer
52 views

How to decide the diameter of a propeller and number of propellers needed in a UAV I am designing? [closed]

I want to design a turboprop aircraft. I know all the design parameters such as lift, thrust, weight etc at a given flight stage. I want to know what the size of the propeller should be.
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2answers
115 views

Will my CRI CRI twin engine plane fly if I replace the engine with a single 15hp gasoline engine? [closed]

I'm using a lighter materials to rebuild plane, to cut down plane weight to 56kg and a 1.2m 3blades propeller.
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3answers
262 views

What purpose do wing root seals serve?

What is the use of wing root seals? What kind of leaks are possible without having wing root seals, and if the seal is broken what kind of issues can airplanes face?
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3answers
195 views

Can control surfaces for slow aircraft be 3D printed?

Can control surfaces for slow aircraft be 3D printed or even just printed as a core and then wrapped in fibreglass or carbon fibre? I understand that 3D printing of wings, etc. is pretty common in the ...
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2answers
98 views

See-through/transparent aircraft [closed]

I am a pilot who loves the aviation experience. Can we build a full see through plane using material as strong as the current materials used to build the body of an aircraft. Is there research or work ...
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0answers
50 views

Boundary layer thickness calculation

I have tried to calculate all the losses associated with the serpentine intake to calculate the total pressure recovery. I have considered the frictional losses, pressure loss due to bend, approach ...
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2answers
2k views

Do manufactures list the maximum speed of an aircraft based on its theoretical maximum speed or dive speed?

I know that the absolute maximum velocity of an aircraft is based on the thrust available. However the aircraft is usually limited beforehand by other speed limits such as dive speed and Mach Never ...
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1answer
79 views

What is the Mach Never Exceed number for a C-130J Hercules under ISA conditions (approximations are welcomed!)

I am looking for the Mach Never Exceed number for a C-130J Hercules so that I can create an approximate 1g envelope. Does anyone have any idea what this can be? I am trying to find the value for ...
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2answers
3k views

Why are there double hinge lines on the rudders of the Grumman C-2?

Why are there two sets of hinge lines on the rudders of the Grumman C-2? A photo from the related ASE question Why does the C-2 left inboard stab not have a rudder? Why would two hinge lines provide ...
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0answers
39 views

What are typical control surface deflection “rate” limits for transport airplanes?

I was wondering if anyone knows what are some typical control surface/actuator deflection "rate" limits for transport airplanes (i.e. aileron/elevator/rudder deflection rates)? I haven't ...
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1answer
45 views

What are the best methods for calculating lift during different stages of flight?

Supposing I have the all dimensions of an RC airplane: wingspan, NACA airfoil, aspect ratio, fuselage length, etc., what would be the best methods of calculating the expected lift the aircraft should ...
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1answer
129 views

Is the location of the strake ( chines) on the two seat F-16 variant is the same as for the one seat one?

Is the location/length of the chines (the cobra hood looking) on the two seat F-16 variant the same as the ones on the single seat variant? The two seat variant has a longer cabin, so it must be ...
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5answers
5k views

Why are 3- or 4-seat gliders so rare?

Sailplanes capable of climbing in rising air (not troop transports, which can only descend after the towrope releases) have one or two seats. I know of only one type with more, the Schweizer SGS 2-32 ...
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1answer
96 views

How do I determine the diameter of my propeller at high altitudes? [duplicate]

I'm designing a electrically propulsed HALE UAS and I need to find the diameter of my propeller to find my thrust. Is there an equation for propeller diameter that doesn't rely on knowing my thrust or ...
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3answers
8k views

Is it dangerous for a supersonic aircraft to fly at exactly Mach 1?

If a plane that is designed for supersonic flight, say the Concorde, kept flying at exactly the speed of sound, would there be any danger in that? If so, what could get dangerous at constant Mach 1 ...
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1answer
98 views

What are the difficulties in building transonic airliners?

If the sonic boom is an issue, why don't we build airliners that are capable of flying just below Mach 1? Big airliners fly at Mach 0.85 at most, and the record for current sub-/transonic civilian ...
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1answer
88 views

What is the difference between aircraft integration and assembly?

I have never had a clear understanding of the difference between aircraft assembly and integration. My understanding is that putting together the airframe alone is assembly and putting together the ...
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1answer
85 views

What thrust is used for thrust to weight ratio?

Performing some preliminary calculations for an aircraft design I have and was wondering what thrust I should use to calculate thrust to weight? The thrust calculations I have, vary due to speed (...
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2answers
164 views

Where is the center of gravity on a tiltrotor?

From what I understand, the CG of full-sized fixed-wing airplanes need to be forward of the wing's center of lift for stability. But the CG of a helicopter must be directly below the rotors since it ...
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2answers
157 views

Why do privater jets often fly at or above FL 400, but large commercial aircraft are usually in the range of FL 300 to FL 400? [duplicate]

With rare exceptions (like the Embraer business jet, which is simply their commercial jet with a different interior), almost all private jets fly in the more rarified air above FL 400. But, if its ...
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1answer
226 views

Why are some modern military trainer aircraft so bulky?

Modern military trainer aircraft are a lot wider and bulkier than the previous generation. Especially the canopy looks oversized. You can see this in the Boeing/Saab T-7 Red Hawk, Alenia Aermacchi M-...
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1answer
105 views

In wing design, how is factor of safety related to G-limits?

What does factor of safety mean with regard to the maximum G force an aircraft is rated for? Does a rating of 3Gs mean the same as a safety factor of 3? Or is there some extra margin?
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1answer
111 views

Optimizing the airplane for best cruising altitude and velocity

In the conceptual phase of the design, I am optimizing various entities of an airplane for the best cruising altitude and speed to reduce the cost, which also includes MTOW and fuel weight. Consider a ...
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2answers
336 views

What made Concorde so heavy?

The Concorde burnt five times more fuel per passenger mile than the 747. A huge contributor must have been the immense empty weight per seat, three times that of the B747. B747-300 Concorde Empty ...
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2answers
6k views

How exactly did engineers come to the final design of jets like the F-16 or SR-71?

I ask this question because I read somewhere that SR-71 was designed in 60's with hand calculations and drafters and when engineers later tried to improve the design with modern computers they found ...
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2answers
205 views

What justifies a biplane over a braced monoplane?

Biplanes became the first airplanes to enter service due to their structurally efficient design being more suitable for the weak materials then. This efficiency comes from the two wings acting as the ...
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1answer
122 views

Is a flying wing optimal for high altitude craft?

One of the biggest problems with flying wings is their sheer thickness, which creates excessive drag. However, since high altitude craft need bigger (and thus thicker) wings anyway, and since weight ...
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1answer
219 views

What surface materials do airplanes use to reduce friction?

Full swimming body suits were banned from Olympic Games a few years ago because some materials have less friction than skin and contestants that could not afford gear to increase their performance ...
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1answer
134 views

What should be the thrust weight ratio for takeoff? [closed]

I am doing some calculations for preliminary design of an airplane and I was wondering how I would go about determining the minimum thrust to weight ratio needed for the aircraft to takeoff. Which ...
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1answer
2k views

Why do propellors have white markings on their tips? [duplicate]

Why do propellors have white markings on their tips? Here are a couple of examples:
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8answers
10k views

Why don’t airplanes use turn signals?

Why don’t airplanes use turn signals like cars do? Would this improve safety for ground operations at uncontrolled airports? Could a similar concept be used to indicate in air maneuvers? For example: ...
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4answers
7k views

Why don't modern fighter aircraft hide their engine exhaust?

In many photographs, the F-4's unique geometry hides one or both engines. I've been told that this is one of the terrific accidental features of the F-4, as it would help shield the hot exhaust from ...

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