Airframe Flashcards
What is the skin of a DA42 made from?
GFRP (glass fibre reenforced plastic), is strong and flexible. Where extra strength required CFRP (carbon fibre reenforced plastic), is more strong and rigid.
They are bonded together by resin.
What type of construction is the structure?
A semi monocoque shell sandwich construction (2 bald CFRP cores), made from two skins (GFRP/CFRP) and core made of rigid foam
Describe the centre section of the DA42
Attaches the fuselage and is integral to the fuselage. Has mountings for the wings, engine nacelles and landing gear, from the fore/aft spars.
Describe in as much detail the wings design
Cantilever wing (no external strut).
Semi monocoque with 2 CFRP shells and a rigid foam core
13.4m wingspan (44ft).
Electrochemical pain between shell and white paint to equalise the static electricity build up.
Two I section spars.
Describe in as much detail the stabiliser
2 spars fire/aft.
2 shells of GFRP
Why is a lightning system required? Describe it in detail
Because the composite structure of the DA42 does not effectively conduct electricity.
The bonding system is made of high capacity aluminium alloy tubes, made up of a longitudinal and lateral axis (left longitudinal axis transfers to lightning rod on the top of tail, RH stops at step).
All metal components and grounding plane attach to this system.
Metal strips connect this system to conductive components (LDG gears engine, skin , fuel tanks etc)
How does the static discharge system work?
Removes static electricity build up through 7 static wicks.
An electrochemical conductive filler is between the shell/paint that allows this built up charge to flow to the wicks, as the composite structure won’t allow the flow of charge.
Advantages/disadvantages of a composite material (GFRP)?
A: strong, light
D: expensive, difficult to repair, adhesive failure
Where is CFRP used vs GFRP
CFRP: fuselage, wings, ailerons, flaps
GFRP: h stabiliser, inner aileron/flap skin, elevator, rudder
