by its shape forcing the air to move faster. If

you change the shape of the wing, obviously

you alter the air flow and that can help you to

generate either more or less lift. In the wings

and tails of most aeroplanes there are movable

flaps which are known as control surfaces.

I’m more a spanners and hammers

man – but it was obviously going

to be fun helping put the

HPA together.

The control surfaces in the wings are called

ailerons. These work as opposites, so that if the

pilot pushes his joystick or control column left,

then the left wing aileron flap is raised and the

right one lowered. This changes the air flow

over the wings so that the left wing generates

less lift than the right wing. As a result the right

wing rises, causing the aircraft to bank left.

There are similar control surfaces in the tail.

On the horizontal tail ‘wing’ there are flaps

called elevators. These work together to raise

or lower the tail, thereby pointing the nose of

the aeroplane upwards or downwards. In the

upright ‘fin’ of the tail there is a rudder which

works just like the rudder on a ship, helping to

point the nose of the plane either right or left.

Our HPA was going to do without control

surfaces in the wings, but the tail was to have

both rudder and elevators. Steering the HPA

with the rudder would give us all the control

we needed. A dynamic, banking turn when

you are just a few feet off the ground and your

wingspan is more than 60 feet is almost bound

to end in you ploughing a furrow with your

wingtip and bringing the whole HPA crashing

to the ground. Best to avoid that, really. I would

find out later exactly how to operate these

controls. In the meantime, we had an aeroplane

to build, and this was going to involve messing

about with foam.

Lightweight foam and clingfilm aren’t really the
sort of materials I’m used to working with – I’m
more a spanners and hammers man – but it was
obviously going to be fun helping put the HPA

together, and the whole process had to start with

the manufacture of the parts.

Constructing the Wings

Messing about in foam might make you think

of one of those parties, but the foam we were

about to mess about with was far more serious

stuff. Ben Tindale was my guide to working

with foam. An expert in robotics engineering,

Australian-born Ben has built some fantastic

machines for his company, Tindale Systems,

to manufacture all manner of tools and

components. He was to take the CAD (computer

aided design) blueprints from Alex’s team and

turn them into actual components.

The machines Ben worked with produced

components that were accurately engineered

to within fractions of a millimetre, yet he too,

like Alex and his team, applied a ‘suck it and

see’, trial-and-error approach to the HPA.

Despite all the time they spent on painstaking

calculations, they were always willing to go

back to the drawing board if something didn’t

work. Ben described projects like the HPA as

encompassing his ‘Holy Trinity’, as he put it:

‘You think a bit; you build a bit; then you go

out and hurt yourself. It’s amazing how you

can come up with a better idea when your knees

are bleeding!’

A bit of a joker he may be, but Ben’s machines

were something else. With the CAD design

for a wing section programmed into his foam

fabrication machine, I stood back and marvelled

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HUMAN POWERED AIRCRAFT