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Australian innovation in small aircraft design : A case study
Outcomes:
H1.1 describes the scope of engineering and critically analyses current innovations
H4.1 investigates the extent of technological change in engineering
Design Concept:
The following pictures present a light aircraft that is not quite in production as yet and will be sold in "kit" form. It has been designed, modelled, wind tunnel tested and structurally analysed all of which costs millions of dollars before it is even built.
It's innovative design includes the latest Global Positioning System (GPS) and satellite navigation (Satnav) instrumentation and it is also far safer than any existing equivalent aircraft. The cabin has a frame rather like a "roll cage" which will give its occupants a better chance of survival in a crash.
Computer-generated image
of the P99L, a single-engined 4-seater aircraft currently being
designed by Page Aircraft Company for manufacturing in kit form
by Australian Lightwing.
Driven directly from a
computer program called Catia, an industry-standard computer
application, the designed model is cut out on a 3-axis milling
machine to generate a scale model for use in wind tunnel testing.
Why is MDF craftwood being used for the model?
The NASA
machine shop 
shows the use of an alternative modelling process
and material.
The model, after machining, is placed in the University of New South Wales recirculating wind tunnel to measure the forces and moments generated by the aerodynamics. The aircraft is also tufted to show the direction of air flow.
- What is meant by "lift" and "drag" in aircraft design.
- What is meant by "stall".
- From the image above, how can you tell this aircraft has stalled?
For more information on general
flight theory visit the How Things Fly home page and click on the "How does a jet weighing thousands of pounds fly?" link in the graphic
Structural concept:
The aircraft has classical aerodynamic surfaces of aluminium alloy with:
- composite fuselage
- a load carrying structure of welded steel in the vicinity of the cabin, this is like a safety cell or roll cage in a racing car
- an aluminium alloy skin
- Why is welded steel used rather than aluminium alloy?
- How might the frame be checked for fatigue cracks? (ultrasonic, X-ray, etc.)
- What material would be used to "skin" this aircraft? (duralumin)
- What is the difference between a monocoque, semi-monocoque and framed structure?
- What type of structure is the P99L aircraft and why is this innovative?
- What is the difference between a strutted wing and a cantilevered wing?
- What purpose does the strut serve in a strutted wing?
- What type of wing does this plane have?
Structural Analysis:
The model is broken up into a number of small parts so that the applied loads and reactions can be examined.
Once the applied load's, reactions and displacements for each part are determined, the induced stress and strains within each part can be calculated.
Once the maximum stress and strains have been calculated for each part the aeronautical engineer can then use this information to determine other factors. What are two other factors that can be decided next? (suitable materials and their minimum physical size for a given part).
The applied loads can be either static or dynamic. What is the difference between these two load types?
After design, calculation and other factors are complete a prototype will need to be built. What is a prototype and what purpose does this serve in the design of a new aircraft?
The designers' dream realised:
A P99L flying over Sydney Harbour Bridge.
All pictures courtesy of Page Aircraft Company Pty Ltd.
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