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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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Can the divergence Mach be greater than 1?

I know that by decreasing t/c and increasing the sweep angle it is possible to increase the divergence Mach, but what is the limit? I am calculating the Mach for a wing with a quarter chord sweep ...
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202 views

What drives the design decision of where to place the refueling receptacle?

What has driven the decision to place the refueling receptacle behind the pilot and to rear of the plane. Is this simply driven by the change away from drogue and probe and the location decided by ...
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155 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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377 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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669 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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242 views

How has CAD influenced aircraft design in the last few decades?

I know that computer aided design was used extensively when designing the Boeing 777, are there any other good examples of aircraft where CAD was essential in the design process? Are there any major ...
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172 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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178 views

Why do early airliners have “backward slope” windows

Does anyone know why many 1930's airliners in the US have cockpit windows that slope down and rearward, the opposite of what you might expect? Consider the Boeing 247: https://www.flickr.com/photos/...
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201 views

How are forward and aft CG limits calculated?

I have been tasked to create a POH for my aero engineering coursework and part of this task is to create the CG envelope for the theoretical 65 passenger aircraft. I have figured out weight, moment ...
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118 views

In xflr5,how is the value of Fz calculated?

I am building an conventional plane with AR=6 and I find the wing area,A.So I have selected an airfoil for building my plane that is sd7062. Using xflr5 I got a cl vs alpha graph and I took the cl ...
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1k views

How do you calculate the lift coefficient of an airfoil at zero angle of attack?

Thin airfoil theory gives $C = C_o + 2\pi\alpha$, where $C_o$ is the lift coefficient at $\alpha = 0$. However, I couldn't find any equation to calculate what $C_o$ is which must be some function of ...
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369 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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106 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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193 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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115 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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36 views

What is the effect of aileron deflection on the centre of pressure?

Deflecting an aileron will increase or decrease the camber of the outer wing where the aileron is attached. I learnt on this platform that centre of pressure (c.p.) moves fore and aft with aileron ...
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20 views

How does Mach number of Jet engine vary with respect to Compression Ratio?

How does the performance of jet engine vary with Compression ratio. What are the variables that affect the Mach number of Jet engine.
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52 views

What is the effect of the Load Factor on wing Structures?

I am quite confused with the definition of Load factor and how it applies to the wing structures of an aircraft. For example, you have an Aircraft being subjected to a Load Factor of 2 and whose ...
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86 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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85 views

Why does the Comet's horizontal stabilizer have so much dihedral?

The Comet's horizontal tail has a noticeably extreme amount of dihedral compared to that of, say, a 707: (Image by MilborneOne at Wikimedia Commons.) Note how the Comet's tail has about twice as ...
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143 views

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

Snow and ice buildup on aircraft (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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0answers
88 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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56 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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48 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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42 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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366 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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280 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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206 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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0answers
169 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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79 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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0answers
18 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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16 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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57 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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34 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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44 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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24 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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0answers
54 views

How to determine the bulge of an airfoil?

In calculation or designing, how to determine the airfoil bulge (thickness)? What is the guideline or consideration in designing airplane's wing? We all know that the bulge (the ticker in the airfoil) ...
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50 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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158 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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46 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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83 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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77 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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0answers
235 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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0answers
108 views

In theory which causes more parasitic drag? A large smooth wing or a small, rough exhaust port?

I'm new to aviation and I have a basic, mechanical question. Wings produce a lot of lift-induced drag, especially at lower speeds. But according to this chart that drops off as velocity increases. ...
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181 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?
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214 views

Was there really a wide gap between the performance of the F-16 similar contestants in the Lightweight Fighter Contest?

Five manufacturers submitted proposals – Vought's V-1100, Lockheed's CL-1200 the Boeing Model 908 and the F-16 and F-17. The F-16 turned out to be an agile dogfighter with "superior acceleration, ...
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292 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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246 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, ...
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344 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 ...