Questions tagged [aircraft-design]

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

71 questions with no upvoted or accepted answers
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5
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0answers
95 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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1answer
768 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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192 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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512 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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969 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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190 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" ...
4
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1answer
93 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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95 views

What effect did the AWACS radar dome have on the stability of the 707?

The large disc shape of the AWACS radar dome, and its attachment pylons to the fuselage, above and behind the wings, seem to have the potential to actually improve the pitch and yaw stability of the ...
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180 views

Has any pilot successfully flown through a hurricane with a single-engine prop plane?

Has any pilot successfully flown or could a pilot crab through a hurricane using a plane such as a Cessna or bi-plane? Would acrobatic planes work better because of their nimble agility and high power-...
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34 views

How much does the design, implementation, test and certification of a Passenger-to-Freighter Conversion cost?

This question answers how much it costs to convert a given aircraft from passenger to freighter once the STC is approved by the FAA. How much does it cost to obtain the STC in the first place? If this ...
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110 views

How hot is the outer casing of a turbofan engine?

I am able to find temperatures inside different components of turbofan engines, but I can't seem to find what would be the temperature of the external casing/shell of the engine. For example, ...
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75 views

How much thrust does the Lilium aircraft produce?

I have been researching the Lilium aircraft and can’t find information about thrust. An early version of this aircraft was 2 seats with a loaded weight of 1,400 lbs, 36 ducted fans and 320 kW peak ...
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108 views

How do jetliners age (major or notable checks and part replacements)?

As commercial airliners can be (and are) operated for many years (or even decades), I've started to ponder - how do they actually age? Or - in other words - what are major or notable maintenance-...
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182 views

Why did the B-52 never have a JT4A-powered version?

All versions of the B-52 use the Pratt & Whitney JT3C turbojet (except for the last version, the B-52H, which uses the JT3D low-bypass turbofan instead). Problem: the JT3C is a horribly anemic ...
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136 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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81 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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243 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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215 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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251 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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156 views

During WWII, what did internal bomb bays and turret layout look like on flying boats?

I am writing an alternate WWII story, and I was wondering if you fine fellows on this site could help me. I am trying to make a fantasy bomber version of the USN Boeing C-98 Clipper, AKA the Boeing ...
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118 views

Can a modern airliner handle turbulence forces of +5/-3G?

In the BOAC Flight 911 accident the 707 likely experienced around positive 5G and negative 2-3G. The wings of the 707 were only about as 50% as flexible as the wings of airliners today. How would a ...
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49 views

Why did the dividing wall separating the engine intakes of early twin-engine Westland Wessexes cause difficulties with intake anti-icing?

The Rolls-Royce1 Gnome-engined variants of the Westland Wessex helicopter family (i.e., the twin-engined versions)2 draw air for both engines from a common intake (having been designed prior to the ...
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92 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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117 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 ...
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95 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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60 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 ...
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38 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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134 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 ...
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206 views

How efficient would it be to have a plane with the cockpit in the back?

Would it be efficient to have a passenger planes cockpit move to the back of the plane, rather than the front? What I have in mind is cameras on the fuselage and nosecone that connects to the cockpit ...
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112 views

Did the “feeler” ailerons of the B-52A-F make air-to-air refueling easier than with the B-52G/H?

The B-52G/H uses 8 spoilerons (so it has 8 burning and 8 turning on its wing) and a shortened vertical stabilizer. Spoilerons seem to be very effective for this design, further reducing the need for ...
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325 views

Why does the KC-46 use an MCAS?

The KC-46 tanker aircraft (the U.S. military's designation for the 767s it uses as tankers, and which every other country calls the KC-767) uses an early version of an MCAS.1 This was ostensibly ...
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76 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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40 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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470 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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35 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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63 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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1answer
134 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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108 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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471 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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0answers
2k 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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298 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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83 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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358 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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0answers
397 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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77 views

Make a 3 engine turboprop electric or steam hybrid aircraft?

Was thinking about this, have a 2 engine regular turboprop with a third electric engine for extra performance (imagine a DC3 like the Conroy Tri-Turbo-Three). The 3rd electric engine would be run from ...
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39 views

What is the engine shell temperature?

What are the highest temperature locations in the outer shell on an aircraft engine? Particularly, modern turbofans like the Trent 900 for example. I'm interested in the temperature constraints of ...
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39 views

How to correct dynamic stability of UAV fuselages?

I was trying to design a fuselage model of UAV with considering lift coefficient (CL), after this I analyzed stability of both wing on fuselage. First I did the individual analysis for wing and ...
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113 views

How can a designer deal with a strict requirement when designing an aircraft?

I'm working on designing an aircraft with some specific requirements (Vstall, Vmax, Ceiling, Payload, Range, RoC, Slanding/takeoff etc). I'm following Anderson's and Raymer's ways (trying to find the ...
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1answer
124 views

What is the angle of Incidence of wing of Airbus A320?

What is the Angle of Incidence/ Mounting Angle of the wing of AIRBUS A320?
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23 views

How can we find maximum lift coefficient of Airfoil?

I am trying to find the maximum Lift coefficient for airfoil NACA 64A-404. I chose this airfoil for wing. I am stuck at finding the Clmax. I tried to use javafoil but javafoil is showing Cl less than ...