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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Why do some turbofan-engined Caravelles, but not all, have an anti-shock body at the root of the horizontal stabilizers?

Many turbofan-engined Caravelles have a prominent anti-shock body where the horizontal stabilizers attach to the vertical tail, about a quarter of the way up the latter. (Turbojet-engined Caravelles ...
Vikki's user avatar
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Why do ATR aircraft have a dedicated power management selector for each engine?

ATR aircraft have a split power management selector in order to allow both engines to be commanded seperately.  Source: Magnar Nordal but what is the purpose of having this facility? do pilots ever ...
Aditya Sharma's user avatar
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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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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 ...
user26807's user avatar
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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" ...
motoDrizzt's user avatar
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222 views

Why do some Caravelles have a full outboard wing fence, and some only a partial outboard fence?

The Caravelle has two wing fences on each wing, so as to limit the spanwise airflow (and associated tip-stall problems) that would otherwise occur due to its rearward-swept wings. On most Caravelles, ...
Vikki's user avatar
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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 ...
jwzumwalt's user avatar
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PZL-104 Wilga and Wilga 2000 slats question

Looking at some details about this aircraft's wing, I wondered why the latest version slat's design has been modified so that it is no longer a continuous slat that runs the whole wingspan, rather ...
user721108's user avatar
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Literature request for effect of Aspect Ratio and Wing Sweep on critical angle of attack?

So I'm trying to find academic literature detailing how both aspect ratio and taper ratio affect the critical angle attack of an aerofoil - namely for a v. low AR wing (AR<1), and high sweep (~75 ...
Harry Karmel's user avatar
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Are airliners designed to land safely with no undercarriage deployed?

Complete undercarriage failure ("belly landing") is very rare in large passenger aircraft, but not unprecedented. (source) I would imagine it would be fairly easy to predict which part of ...
Party Ark's user avatar
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How does the 'efficiency' of a cyclorotor compare to helicopters and fixed wing aircraft?

I recently rediscovered the cyclorotor concept. There is a good example on youtube here. Ignoring the mechanical complexity to an extent how does the 'efficiency' compare to conventional designs? When ...
Bruce Adams's user avatar
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116 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-...
Radioactive Pickle's user avatar
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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 ...
Robert DiGiovanni's user avatar
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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 ...
Vikki's user avatar
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What is the aerodynamic influence of prop spacing and placement in multi-prop engine setups

I saw this question Is there a rule of thumb for spacing between jet engines?, which referred to How do you choose engine placement for under wings engines?, but I was wondering how the engine spacing ...
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What is MZFW and what will happen if an airplane exceeded this weight?

What is MZFW and what will happen if an airplane exceeded this weight? Is that the wing root experiences the highest bending moment under the loading condition corresponding to Maximum Zero Fuel ...
Stan's user avatar
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Anyone knows where i could find the McMaster, H. C., “FAR 23 LOADS”, Aeroscience Software, 2.02 Edition?

I am currently conducting research on wing lift distributions and came across the existence of a software tool called "FAR 23 LOADS," developed by McMaster, H. C. (Aeroscience Software, 2.02 ...
Martin Moreno Vega's user avatar
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110 views

Why there are no fully articulated 2 rotoblades helicopter

Why can't R22 and R44 make the 2 rotoblades fully articulated Like cabri G2 helicopter but only 2 blades So that easier to store in the hanger than 3 blades rotor blades helicopter and no mast bumping ...
CS Tay's user avatar
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Why are turbofan-engined Caravelles' engine pylons open at the back?

The engine pylons of turbofan-engined Caravelles are open at the very back, looking for all the world like someone'd simply taken a saw and sliced off the rearmost portion of the pylon: (Image ...
Vikki's user avatar
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Lifting-Line Theory - Numerical solution for a wing with dihedral angle

I'm trying to calculate lift for a wing with a dihedral angle using the Lifting-Line Theory. While using the thesis "Non-Planar Lifting-Line Theory for Fixed and Deformable Geometries" as a ...
Luan Arita's user avatar
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0 answers
193 views

Why does the EA-18G not have a gold-lined canopy like the Prowlers have?

I noticed on the Growlers that they have a clear canopy compared to the gold lined canopy of a Prowler, Which protects pilots from radiation. If the Growler doesn't have a Gold lined canopy that does ...
Enzo C.'s user avatar
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Is there a difference from alignment with the fuselage between J79 and Spey engine versions used in the F4?

Is there a difference between the J79 and Spey engine versions used in the F4 Phantom in terms of alignment with the fuselage? It looks to me like the Spey nozzles are pointing downward.
George Geo's user avatar
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Why do white marks on the spinners in front of engines have different patterns? Not Yellow? Omitted for some models?

In aeroailas' answer I understand that the cones in front of the props/fans are called spinners. In Farhan's answer I understand that the ehite marks painted onto the spinners act less as scarecrows ...
CrystallizedRefresher's user avatar
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202 views

How are Fan pressure of and Static pressure in the turbofan engine related?

If the fan air is ducted to the rear, the total fan pressure must be higher than the static gas pressure in the primary engine's exhaust, or air will not flow. By the same token, the static fan ...
Noorul Quamar's user avatar
2 votes
0 answers
452 views

How can I design a slotted flap?

I have not been able to find satisfactory methods on design of slotted flaps, or flaps in general. Most of the answers are about eyeballing or experience. Can you guide me on what could be good ...
Mridul's user avatar
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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 ...
nodapic's user avatar
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591 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, ...
Hamza Khalid's user avatar
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88 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 ...
Vikki's user avatar
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2 votes
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300 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 ...
hydraulist's user avatar
2 votes
0 answers
192 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 ...
Amit Regev's user avatar
2 votes
0 answers
704 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?
wolf max's user avatar
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149 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 ...
Simon Henn's user avatar
2 votes
0 answers
600 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 ...
Francis L.'s user avatar
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2 votes
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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 ...
george's user avatar
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How much of the Virgin GlobalFlyer's L/D is due to laminar flow?

Despite travelling much faster than the Voyager, it has a significantly higher L/D. The latter seems to have two features that disrupt laminate flow, that are absent in the former. Namely the canards ...
Abdullah is not an Amalekite's user avatar
1 vote
0 answers
49 views

How can we adjust the features of an airfoil?

We have a base airfoil with Max thickness 11.7% at 28% chord and Max camber 3.4% at 42% chord. Say, we want to draw our own airfoil based on the previous description but with an increase maximum ...
Chopang's user avatar
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What can cause an unstable phugoid mode?

For clarity, I am wondering about how aircraft design can lead to the phugoid poles becoming complex with a positive real part, so an oscillation with increasing amplitudes. My understanding of the ...
Grumpy's user avatar
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1 vote
1 answer
170 views

PZL M28 Skytruck exhaust alignment

Watching a short documentary on PZL M28 Skytruck, I noticed it has quite oddly aligned exhaust pipes. They point almost directly downwards, with only slight aft tilt: Picture credit: Łukasz Golowanow ...
Jpe61's user avatar
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1 vote
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136 views

Why are hydraulic pumps mounted on engines 2 and 3 in BAe 146?

The BAe 146 has 4 engines: engine no. 1 and 4 generate electricity engine no. 2 and 3 generate hydraulic pressure Why was this setup chosen?
Aviator's user avatar
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1 vote
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Are Foward Swept Wings for a Rear Propeller Airplane Feasible?

Would going with a forward swept wing design, with the same cord and length of the "A Wing", bring more air the the propeller and tail to increase range, power, or stability? Consider the ...
Justintimeforfun's user avatar
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0 answers
49 views

Evaluating maximum TAS for a given available power

This is the original problem: A turboprop aircraft with a weight of 162 kN is equipped with a power plant with a power derating model described by $\frac{P_A}{P_{A,0}} = 0.9\sigma^{0.75}$, where $P_{...
kene02's user avatar
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0 answers
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Why are there no new major aircraft in ICAO Aerodrome catagory D?

So the 757, 767, A300 and A310 all were in ICAO cat D (mainly restricted by a wingspan between 36-less than 52m). Now though all these aircraft are discontinued, and there is no new designs looking to ...
Alastair Wyllie's user avatar
1 vote
0 answers
834 views

What are typical values for CLmax in clean configuration?

I know typical cruising CL tends to be in the range of 0,5. Maximum CL I'm guessing around 1. Does anyone know typical values?
stevederekson555's user avatar
1 vote
0 answers
131 views

Why doesn't the -30% SFC fully account for the dramatic reduction in fuel consumption compared to the 1960s?

In looking at the specific fuel consumption (SFC) of some aero engines I find that for example, the Rolls Royce Conway turbofan engine had typical cruise SFC of 0.874 lb/(h lbf) whilst the most modern ...
Fastship's user avatar
1 vote
0 answers
64 views

Texts on aero-engine structures

I have been scouring the web for resources on aero-engine structures and structural design (preferably civil turbofans) but unfortunately it seems like they are hard to come by. I would like dedicated ...
haukit's user avatar
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286 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 ...
Jazzyamx's user avatar
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0 answers
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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 ...
Todd McLauchlin's user avatar
1 vote
0 answers
122 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 ...
Manu H's user avatar
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1 vote
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96 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 ...
how-do-you-do-fellow-kids's user avatar
1 vote
0 answers
61 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 ...
karthikeyan's user avatar