Questions tagged [aircraft-design]

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

55 questions with no upvoted or accepted answers
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5
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62 views

Do UL aircraft complying with LTF-UL need to copy an existing design pattern?

With my current pipe dream being to get physically involved in aviation instead of only theoretically, I looked into the regulations for ultralight planes in Germany. On multiple occasions in the ...
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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
517 views

Is this equation for propeller thrust correct?

From dimensional considerations, and assuming that the power $P$ applied to a propeller of diameter $D$ moving at an axial speed $V$ is 100% converted to the acceleration of a mass of air with density ...
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169 views

What different intake designs are there, and what are their pros and cons?

I noticed that over the years (on fighter jets specifically) there have been many different methods of directing air into the engines. Primarily, the nose-intake, side intake, and underbody intakes ...
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443 views

What is the total lift equation of a helicopter with 3 Flettner rotors?

I'm doing research regarding the possiblity of using Flettner rotors on helicopters. I would like to derive the total lift equation for a helicopter that consist of 3 Flettner rotors. Given that: ...
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751 views

What is the minimum price for a full Glass cockpit for the size of 6 passengers aircraft?

I am working on my final project at school and currently looking for the information about avionics system. We design a concept amphibious aircraft with the info as listed below: 2 pilots in the ...
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178 views

Has there been any research on plasma-producing planes?

Many years ago I read in an expository scientific journal[1] an article about what the future of high speed aviation could be. It said that there were studies on airplanes capable of "plasma-izing" ...
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1answer
184 views

Can structural damage be detected or predicted using historical data?

Can software simulations and structural health monitoring techniques accurately predict damage occurrence in aerospace structures using historical data(...
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1answer
80 views

What is the comparative roughness of fabric surfaces?

"The Design of the Aeroplane" by Darrol Stinton (1983) lists comparative roughness of aircraft skin material (pg 154). Unfortunately it does not list dope & fabric. What is the comparative ...
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64 views

Definition of Critical Part in type certification process

first time here :) I'm part of the team at Flytrex (flytrex.com) and we're working with the Aircraft Certification Office to certify one of the first UAS systems (drones) under new initiative to ...
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120 views

Why are the boundary layer suction holes placed far forward from the engine?

Edit: I know that the suction holes reduce the boundary layer; I am wondering if there is a reason why they are placed far ahead of the engine’s intake. My thinking is that the long duct past the ...
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136 views

In a Boeing 767, what percentage of the aluminum is in structural components?

For a Boeing 767 (model year 2000), does anyone know how much aluminum is in 'structural' components, as a percentage of the total amount? And specifically the wings?
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1answer
386 views

Why is YF22 designed with conventional rudders while YF23 with all-moving rudders?

Are all-moving rudders more stealthy? If so, how come YF22 which is just as fixated with rear body stealthiness as the YF23 comes with conventional ones? Also, all-moving rudders have fixed camber, ...
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208 views

Are there any airplane designs that are (relatively) insensitive to the effects of airframe icing?

Snow and ice buildup on airplanes (especially the wings) is a well-known and feared hazard of cold-weather operations; it roughens the surface of the wings and changes their profile, which combine to ...
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214 views

Why isn't cabin air quality in airliners directly monitored with sensors?

Airliner air conditioning systems refresh the cabin air volume every couple of minutes. A portion of it is filtered and re-circulated into the cabin, however AFAIK there are no direct cabin air ...
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228 views

What Inertial effects should be considered to achieve blade stability on a Variable Pitch Propeller tailoredby aerodynamic loads?

I am developing a self adjusting variable pitch propeller tailored by its pitching moments due to aerodynamic loads setting the blade rotation axis in an offset from the aerodynamic center as shown ...
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147 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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73 views

Where can I place an engine in a twist morphing wing?

I am designing an electric aircraft with a wing that is completely based on the idea of biomimicry, whereas the wing has multiple winglets and can also morph by twisting. It is more like an experiment ...
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1answer
112 views

How is the flow of air through a NACA submerged inlet determined?

This question pertains to the design and/or selection of NACA submerged inlets. I am trying to understand what kind of airflow would enter a NACA submerged inlet/scoop and am looking for a good ...
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78 views

Are there design guidelines for sizing vent/surge tanks?

Could someone explain the sizing process of Vent/ Surge tank of Aircraft fuel system? I understand the Vent tank is to collect fuel overflow from the main fuel tanks. The reason could be due to Fuel ...
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1answer
50 views

Aerodynamic Pressure Loads in FEA of Lifting Surfaces - Query

Let me give a brief summary of the process involved in the FEA of lifting surfaces with the wing as an example: 1. The wing is modelled as a hollow surface body in Ansys, meaning only the exterior ...
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1answer
94 views

What was the decrease in approach speed of the KFIR over the Mirage 5 due to the canards?

The Mirage III approached at 170 knots according to the Dassault. The Mirage NG and the KFIR C2 as well as the Swiss Mirage 5s added canards to the design, what was the decrease in approach speed due ...
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39 views

Looking for Polars for Liebeck LI74 with a Cl of 4.8!

Looking for Polars for Liebeck LI74 with a Cl of 4.8!! Does anyone have any info on this foil?
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94 views

What is the relationship between the Center of Pressure and flap deployment?

I have been reading regarding the Center of Pressure of an airfoil (Cp) and the relationship with angle of attack. What is a good way to explain in layman's terms why the pressure changes in such a ...
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27 views

What is a typical Cd0 value for single-slotted flaps?

I've been having trouble finding any source for what a typical value would be for single-slotted flaps. I haven't been able to find any information within Anderson's Aircraft Performance and Design or ...
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58 views

How to compute actuator torque requirement for Variable pitch mechanism??

Suggest me any reference to compute the torque requirement for actuator/motor to control the pitch angle of propeller (Variable Pitch Propeller). Thanks in advance Arun Ravindran
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123 views

How to calculate the shear centre of a wing?

How is shear centre of a wings calculated? i.e. how can I calculate the wing shear centre of a two spar wing with main spar at 0% of wing chord and rear spar at 75% of wing chord? (Assuming the two ...
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1answer
75 views

How can I use the “control hinge-moment coefficient due to tab” for sizing a trim tab on an elevator?

I calculated the control hinge-moment coefficient due to tab by using the dimensions of a tail and its elevator. However, the trim tab dimension parameters in the calculations were approximated values ...
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76 views

Does Froude Efficiency represent an upper bound for propellers in certain flight / aircraft conditions?

I used the Simple Propeller Theory to calculate the Froude Efficiency for my theoretical propeller-driven craft (at 65k feet). Here are the results: https://ibb.co/kPPqzU. My results were that, for ...
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50 views

Is there any fixed-wing UAV common research model available?

Is there any source of structural specifications data available for a particular fixed-wing UAV, that can be used for comparison with a resulting structure, obtained by a structural optimization ...
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98 views

What‘s the diameter of the engines of the Airbus E-Fan?

does somebody know the diameter of the E-Fan‘s engines ? To me the look like around 80cm or what do you think ? Also, with more and wider blades and 60 kW motors instead of 30 couldn‘t they get much ...
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87 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, ...
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47 views

How can I find the Local Section Moment Coefficient?

I am working on coding the Lifting Line Method, which uses horseshoe vortices to get the dimensionless force and moment vector for parts of a wing. C_mi is a term that means the local section moment ...
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405 views

What aircraft has the highest critical Mach number?

What aircraft has the highest critical Mach number? The highest I heard of was BAC/English Electric Lightning at Mach 0.95. Are there planes with higher Mcrit. and is it plausible to go higher than ...
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1k views

What is the purpose of a fuse pin in a turbine engine?

what's the difference betweeen fuse pin and mounting bolts of an engine ? Are they the same ? Any digram of a GE-90 engine showing those would be appreciated.
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286 views

How does the Bombardier CSeries compare to existing single-aisle jet-liners?

With news breaking in that Airbus will acquire a large part of Bombardier's CSeries program, I'm curious, just how much better are the new planes from Bombardier compared to single aisle planes like ...
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187 views

How many fuselage skin panels are there for the Challenger 605?

How many fuselage skin panels are there for the Bombardier Challenger 605 aircraft, and where are their relative positions? For example, would this be an accurate simple drawing of it?
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82 views

What useful data can be obtained by using building and flying a scale model of a fighter aircraft design?

The use of scale models in the design of modern fighter aircraft seems to be rare, wind tunnel models and software is used instead. Is building and flying a scale model of a jet fighter or trainer ...
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333 views

Can a 40 hp ultralight trike with a 15 m wing take off with simple (homebuilt) tube floats?

There seem to be no floats manufactured for 103 trikes- under 500 pounds including gas and pilot. Seems like they could be smaller and lighter than existing ones. I am considering fabricating floats ...
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362 views

What are the specifications for the CFE738-1-1B?

I'm designing an aircraft for fun, and I've selected a CFE738-1-1B as the engine. It's never going to fly outside of X Plane, but it's still fun, so I'd like to make the X Plane version as realistic ...
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30 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 ...
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150 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?
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85 views

What airfoil is used for the horizontal stabilizer of a 737? Is it inverted?

I cannot find the airfoil of the Boeing 737 horizontal stabilizer or any typical tail airfoil of a civilian aircraft.
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115 views

Has automatic all-seat reclining been tested?

Seat reclining in modern economy-class seats is a problem when person in front of you reclines, but you are still in vertical position. Has there been a consideration of simultaneous reclining of all ...
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74 views

Could a tail rotor serve as a spin breaker for winged aircraft?

It seems that yaw, more than pitch or roll, creates the greatest wing asymmetry in a spin. If the spin progresses to the point where it cannot be broken, some aircraft are equipped with parachutes to ...
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66 views

Is Engine up thrustline actually desirable for “speed stable” designs?

The much maligned Max 8 and the Buckeye Navy trainer. What could they have in common? Both would want static stability (trimmable speed stable approach) for landings. Both would want maximum fuel ...
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49 views

How could I measure frontal area based on a technical drawing?

I want to compare frontal surface areas of two airplanes, and I have their digital technical drawings and wingspan data. What program could I use to obtain the surface area using this data? Esentially ...
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195 views

Calculating induced drag approximation using XFoil generated parasitic drag

I am trying to do rough predictions of induced drag using the XFoil results for parasitic drag. To do so, I am using the lifting line equation for induced drag and the Oswald efficiency number: $C_D=...
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260 views

Will the new Boeing NMA be 'more electric' than the current B787?

I understand that the B787 is the 'most electric' aircraft to date, however there have been many issues with the plane, and I'm interested in knowing if the latest Boeing New Midsize Aircraft (NMA) - ...
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225 views

How can I calculate the fuel weight fraction for a single-engine turbofan GA aircraft?

How would I calculate the fuel weight fraction for different stages of flight for a single turbofan engine general aviation aircraft?