Guidelines Presentation

Aircraft Aim & Judging The aircraft needs to transport the mirror segments of the ESO European Extremely Large Telescope, being built 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 to achieve using the Engineering Flight Simulator.

Payload The aircraft needs to carry 1000 segments of the main mirror – Each mirror segment is hexagonal and 1.5m across, and 0.1 m thick, and weighs 15kg each. These segments can be arranged in the fuselage how ever the designers see fit.

Engineering Flight Simulator The overall concept needs to be planned and draw up ready for the Simulator, and the concept is based on whatever the team decides. The Simulator takes mass, geometric, and aerodynamic information to predict how the aircraft will perform and handle.

Fundamentals For economic flight; drag needs to be low resulting in low thrust requirements; and weight needs to be low requiring less lift generated

Aircraft Axis System

3 View G.A. Drawing example Remember to draw to scale – and note on the drawing what it is.

Areas for consideration Mass Wing Fuselage Tailplane & Fin Propulsion

Mass Mass must include payload mass, propulsion mass, and empty weight of the aircraft To calculate Empty Mass we can use “effective density” – Once 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 “effective density” to gain a good estimation of the aircraft empty mass. Typical Value of “effective density” = 2.58 kg/m 3

Mass – Effective Density

Wing Aerofoil Profile shape will be fixed as NACA The wing must have sufficient area to generate enough lift – Typical Wing loading (Lift/Wing area) = 4700 N/m 2 where the Lift = Zero Fuel Weight = ((Empty mass + Payload mass) x 9.81) For economic wings, they should be more long and thin, like a glider, rather than a delta/triangular – this gives a higher Aspect Ratio. Wing sweep aids high speed flight – shouldn’t need more that 45 degrees – either forward or back!

Aspect Ratio examples High Aspect RatioLow Aspect Ratio

Wing terms and Calculation

Mean Aerodynamic Chord

Dihedral Angle Dihedral can be added to give the plane more wing levelling stability, so the plane flies in a straight line without the Pilot having to control the plane all the time. Positive angle is upwards.

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

Main Wing positioning Place the Aerodynamic centre of the main wing behind the centre of mass of the aircraft as this will impart natural pitch stability.

Fuselage Fuselage layout needs to be an aerodynamic envelope that surrounds the Payload and the Pilots Payload layout is entirely down to the team

Tailplane & Fin Size and positions can be calculated from Fin and Tailplane volumes. Volume = Area of surface x Distance of Aerodynamic Centre from Centre of Gravity Researching and working out volumes from existing aircraft will give typical values. Centres of Gravity can be estimated by it being 1m forwards of the rear wheels. Aerodynamic Centres of Fin and Tailplane can be calculated in the same way as for the main wing.

Example Fin Volume Fin Volume = Tail Arm x Fin Area

Fin & Tailplane examples

Propulsion Choice of type of engines – Propeller or Jet propulsion is a design choice. Propeller - Typical BHP/Zero Fuel Weight Ratio = 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 by multiplying this value by Thrust/Weight Ratio. Then choice of size, number and position of engines can be made.

Controls Control surfaces deflect to produce aerodynamic force which the Pilot uses to control the flight direction. Angles can be suggested, and will be refined during flight testing. Aileron Span fraction is the length of both ailerons divided by the overall wing span. Moment arm is the distance from the aerodynamic centre of the aileron to the plane’s centre of gravity

Be innovative in design

Questions