Higher Trails

Jerry Seinfeld once said, “the reason people are scared of flying is because people can’t fly. He says, it’s like putting a fish in a car, it’s just not right!” His of course was a humorous take on human behaviour but he must be fish-mouthed, like I am, by developments in wingsuit flying these days!

Wingsuits

“Wings were first used in the 1930s as an attempt to increase horizontal movement. It’s the art of flying the human body through the air using a special jumpsuit, called a wingsuit that shapes the human body into an airfoil that can create lift. The wingsuit creates the airfoil shape with fabric sewn between the legs and under the arms. It’s also called a birdman suit or squirrel suit. I should tell you from the get go that wingsuit fliers are generally, skydivers with a minimum of 200 logged jumps.

A wingsuit flier manipulates the shape of their body to create the desired amount of lift and drag although most Birdman suits have a 2 to 1 ratio. This means that for every foot they drop, they go 2 feet foward. With body shape manipulation and by choosing the design characteristics of the wingsuit, a flier can alter both their forward speed and their fall rate towards the Earth.

A person can choose to manipulate their fall rate towards Earth with the goal of achieving the slowest vertical speed in order to prolong time in freefall, or the pilot can try to maximize the horizontal glide distance across the Earth. They manipulate these flight characteristics by changing the shape of their torso, arching or bending at the shoulders, hips, and knees, and by changing the angle of attack in which the wingsuit flies in the relative wind, and by the amount of tension applied to the fabric wings of the suit.

A typical skydiver’s terminal velocity in belly to earth orientation ranges from 110 to 140 mph or from 180 to 225 km/h. A wingsuit can reduce these speeds dramatically, a momentary speed of 25 mph or 40 km/h has been recorded, however 60 mph or 95 km/h is more typical. The suit also enables the wearer to travel longer distances horizontally; glide ratios of 2.5:1 are commonplace. Currently, there are two basic wingsuit types. The tri-wing Wingsuit has three individual ram-air wings attached under the arms and between the legs. The mono-wing wing suit design incorporates the whole suit into one large wing.

Wingloading: The Bumblebee

In a different vein, 20th century folklore tried to convince us that the bumblebee should be incapable of flight, as it doesn’t have the capacity (in terms of wing size or beat per second) to achieve flight with the degree of wing loading necessary. Not being aware of scientists ‘proving’ it cannot fly, the bumblebee succeeds under “the power of its own ignorance”. Wonderful isn’t it, the way nature confounds us!

The origins and perpetuation of this myth have been difficult to pin down with any certainty but with such an obvious refute I’d have thought the naysayers would have simply disappeared into the woodwork. I wonder sometimes just who really is ignorant! Some credit physicist Ludwig Prandtl (1875—1953) of the University of Göttingen in Germany with popularising the myth though several others were named as suspects too.

In 1934, French entomologist Antoine Manan included the following passage in the introduction to his book Le Vol des Insectes: ‘Tout d’abord poussé par ce qui fait en aviation, j’ai appliqué aux insectes les lois de la résistance de l’air, et je suis arrivé avec M. SAINTE-LAGUE a cette conclusion que leur vol est impossible.’ Magnan refers to his assistant André Saint-Lagué, who was apparently an engineer. Loosely translated he comes to the conclusion that bumble bees can’t fly and collars his assistant into the collaboration for good measure. I don’t think this was a particularly good turn by Manan for his assistant myself!

More modern day sophistication in aerodynamic analysis show that the bumblebee can fly because its wings encounter dynamic stall in every oscillation cycle. Another description of a bee’s wing function is that the wings work similarly to helicopter blades, ‘reverse-pitch semirotary helicopter blades’. Bees beat their wings approximately 200 times a second, which is 10-20x as fast as nerve impulses can fire. They achieve this because their thorax muscles don’t expand and contract on each nerve firing, but rather vibrate like someone plucking a rubber-band. It’s fascinating isn’t it!

1936 DH82 de Havilland Tiger Moth

In Waipukurau my local Aero Club is the proud owner of a 1936 DH82 de Havilland Tiger Moth. The de Havilland Aircraft Company (less commonly spelled de Haviland) was a British aviation manufacturer founded in 1920 when Airco, of which Geoffrey de Havilland had been chief designer and owner, was sold to BSA. De Havilland then set up a company under his name in September of that year at Stag Lane Aerodrome in Edgware, England. The company later moved to Hatfield in Hertfordshire, England. De Havilland Aircraft Company was responsible for producing the first passenger jet and other innovative aircraft.

The de Havilland DH 82 Tiger Moth is a 1930s biplane designed by Geoffrey de Havilland and was operated by the Royal Air Force and others as a primary trainer. The Tiger Moth remained in service with the RAF until 1952 when many of the surplus aircraft entered civil operation. Many other nations used the Tiger Moth both in military and civil applications and the ubiquitous little trainer is still in great demand worldwide as a recreational aircraft. In my home town people come from right around the country and all over the world for a flight in this handsome vintage plane.

There’s an inexplicable feeling of unencumbered freedom about flying, I haven’t done so much actual flying over the past number of years but in earlier years I did a lot. In 1975 John Hanlon wrote and recorded ‘Higher Trails’ a song that always plays in my head whenever I fly.

My old friend Marcellus who’s a restauranter in Sydney is actually a qualified commercial pilot. His eyes light up when he talks about flying, that light in the eyes is instantly recognisable in those who love it. Watching the guys hang glide in the clip gives me that sense every time. Watch. Feel.

Update November 2009

Since I last wrote my friend Marcellus has sold his restaurant. I also present you with an opportunity to see actual wingsuit footage. Wingsuit jumping is the leading edge of extreme sports. Ueli Gegenschatz talks about how and why he does it, and shows jawdropping film.

Sadly, on 11 November, 2009, during a jump from the Sunrise Tower in Zurich, Switzerland, a gust of wind hit him and he lost control of his jump. He hit the ground and was seriously injured. He died two days later on 13 November, 2009.