aircraft design competition.ppt

8/12/2019 Aircraft Design Competition.ppt

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Guidelines Presentation


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Aircraft Aim & Judging

The aircraft needs to transport the mirror segments of

the ESO European Extremely Large Telescope, beingbuilt by OpTIC Glyndwr, in the most economical way.

To judge this, we will look at the flight range with a

given amount of fuel that each aircraft will be able toachieve using the Engineering Flight Simulator.


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Payload The aircraft needs to carry 1000 segments of the main

mirror Each mirror segment is hexagonal and 1.5macross, and 0.1 m thick, and weighs 15kg each.

These segments can be arranged in the fuselage however the designers see fit.


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Engineering Flight SimulatorThe overall concept needs to be planned and draw upready for the Simulator, and the concept is based onwhatever the team decides.

The Simulator takes mass, geometric, andaerodynamic information to predict how the aircraftwill perform and handle.


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Fundamentals

For economic flight; drag needs to be low resulting in lowthrust requirements; and weight needs to be low requiring lesslift generated


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Aircraft Axis System


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3 View G.A. Drawing exampleRemember todraw to scale

and note onthe drawingwhat it is.


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Areas for consideration

Mass

Wing

Fuselage Tailplane & Fin

Propulsion


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Mass Mass must include payload mass, propulsion mass,

and empty weight of the aircraft

To calculate Empty Mass we can use effective densityOnce the overall aircraft has been drawn, use length,wingspan and height to create a box round the aircraft.This volume can then be multiplied by effectivedensity to gain a good estimation of the aircraft emptymass.

Typical Value of effective density = 2.58 kg/m3


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Mass

Effective Density


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WingAerofoil Profile shape will be fixed as NACA 23015

The wing must have sufficient area to generate enough

lift Typical Wing loading (Lift/Wing area) = 4700N/m2where the Lift = Zero Fuel Weight = ((Emptymass + Payload mass) x 9.81)

For economic wings, they should be more long and

thin, like a glider, rather than a delta/triangular thisgives a higher Aspect Ratio.

Wing sweep aids high speed flight shouldnt needmore that 45 degrees either forward or back!


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Aspect Ratio examples

High Aspect Ratio Low Aspect Ratio


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Wing terms and Calculation


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Mean Aerodynamic Chord


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Dihedral AngleDihedral can be addedto give the plane more

wing levelling stability,so the plane flies in astraight line withoutthe Pilot having tocontrol the plane all

the time. Positiveangle is upwards.


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Wing setting angle

Wing setting angle is usually a small angle,from 0 to 5 degrees gives good compromisebetween take off and the cruise conditions


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Main Wing positioningPlace the

Aerodynamic centre

of the main wingbehind the centre ofmass of the aircraftas this will impartnatural pitch

stability.


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Tailplane & Fin Size and positions can be calculated from Fin and

Tailplane volumes.

Volume = Area of surface x Distance of AerodynamicCentre from Centre of Gravity

Researching and working out volumes from existingaircraft will give typical values. Centres of Gravity can

be estimated by it being 1m forwards of the rearwheels.

Aerodynamic Centres of Fin and Tailplane can becalculated in the same way as for the main wing.


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Example Fin Volume

Fin Volume = Tail Arm x Fin Area


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Fin & Tailplane examples


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Propulsion Choice of type of engines Propeller or Jet propulsion

is a design choice.

Propeller - Typical BHP/Zero Fuel Weight Ratio =0.092

Jet - Typical Thrust/Zero Fuel Weight Ratio = 0.4

Using Zero Fuel Weight = ((Empty mass + Payload

mass) x 9.81) we can work out Thrust requirement bymultiplying this value by Thrust/Weight Ratio.

Then choice of size, number and position of enginescan be made.


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Controls

Control surfaces deflect toproduce aerodynamic force

which the Pilot uses tocontrol the flight direction.

Angles can be suggested,and will be refined duringflight testing.

Aileron Span fraction is thelength of both aileronsdivided by the overall wingspan.

Moment arm is the distancefrom the aerodynamiccentre of the aileron to theplanes centre of gravity


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Be innovative in design


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Questions

aircraft design competition.ppt

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