'The Children of the Wind' - A History of the New Aviation 1971-1996 - Ch V, Pt 1

[Larry Dighera, Moderator]

'The Children of the Wind' - A History of the New Aviation 1971-1996

Here is a serialized account taken from Brian Miltion's magnum
opus, 'The Children of the Wind' - A History of the New Aviation
1971-1996, soon to be published by Endeavour Press, a
London-based epublisher. These first few chapters
chronicling the beginnings of man's quest to fly and how the
forefathers of aviation have influenced contemporary ultralight
aviation have kindly been made available to newsgroup
readers. They will be posted here over the next few months.
This first post is the Table of Contents.

You can learn more about TV presenter, lecturer,
journalist, award winning around-the-world microlight pilot,
author of seven books, and born adventurer, Brian Milton on
his web site <http://www.brian-milton.com/>;. You can also
purchase autographed copies of Brian's literary works there too:
<http://www.brian-milton.com/book>. And don't miss the
extensive collection of aviation videos, including Brian's Around
the World by Microlight flight for which he was awarded the
Britannia Trophy, joining a very distinguished list of aviators
who have won that award including Sir John Alcock, Bert Hinkler
and Sir Alan Cobham. Brian was also awarded the Segrave Trophy,
an award presented to great sportsmen; past recipients include Sir
Malcolm Campbell, Amy Johnson and Jackie Stewart:
<http://www.brian-milton.com/video/>

Additional links:
http://en.wikipedia.org/wiki/Brian_Milton
http://en.wikipedia.org/wiki/Segrave_Trophy


© Copyright Brian Milton 2013, All Rights Reserved


============= Beginning of Chapter V, Part 1 ==============

Chapter Five - LEARNING TO CROSS-COUNTRY

The six years from 1975 to 1981 saw a complete revolution in hang gliding, in
Britain as in the US. In the beginning, there was much spirited debate about
the Selsey Birdman competition (now the Bognor Birdman) in which contestants
try to fly 50 metres with only a 5 metre platform to run along, just under 8
metres high. Within two years an American had flown more than a hundred miles.
Within four years, this distance had been flown in England. Yet Selsey was one
of our roots and does not deserve the scorn it attracted from pilots worried
about the micky-mouse image it gives the sport. Selsey has its share of the
holy lunacy of our founding fathers.

Thousands of people are attracted to the Southern Coastal town of Selsey for
one day a year to watch contestants try and win £10,000 by flying fifty metres.
The 'flyers' are not allowed to use helpers to boost their flight, and all end
up in the sea, most of them dressed as chickens or cod-aircraft, quite happy to
be ridiculous. But a small dedicated band, including a former lieutenant
commander in the Royal Navy, Mike Collis, author of the "Pilot's Creed", and a
microlight manufacturer, David Cook, really set out to win. The organizers
stage the event for charity, and have been alarmed at the seriousness of some
of the Selsey attempts. One year the chairman of the Selsey Birdman took the
cheque out of his pocket and looked at it sadly when David Cook made what
appeared to be a winning flight. But Cook's attempt was judged to have been
unfairly boosted by people pushing him off the platform, and ending in the sea
themselves, so Selsey was still there to be won. Mike Collis nurtured hopes for
years of winning with a foot-powered hang-glider, peddling a propeller on its
nose, and called 'Tweetie'.

Yet a year before the Selsey Debate - "Is Selsey possible?" – which focussed on
an aspect of the New Aviation that was truly a dead end, there was already a
real and valid discussion about how to actually fly, to leave the ridge like a
bird and disappear. A young pilot who went on to beat many of the best in the
world, Graham Hobson, began to think about turbulence. He had come across it in
flight, as we all had. But instead of pulling the bar in, as Ken Messenger did
on Snowdon, or landing, as Tony Fuell did on Ditchling, he began to explore the
very nature of the turbulence. Hobson's sense of wonder at what he is
discovering, a long time after it was formalized in mainstream sailplaning,
comes through in an article he wrote at the time...

…I am writing with the news of two hang gliding deaths and one serious injury
still weighing heavily on my mind. It makes me ask myself if I am in the right
game, especially when I received the news at the end of a day's thermal soaring
to altitudes of probably 1,000 feet. The answer to this question you will
probably glean from the following account.

Before I continue I would like to say I don't know exactly what a thermal is,
and the lift which I am referring to as a thermal is that which one can get
whilst soaring in the usual ridge pressure band beneath a passing cloud.
Suddenly, the control bar pulls strongly and the ground drops away rapidly.
Often this lift is spasmodic and accompanied by a considerable amount of
turbulence, but if the pilot can "hold on" (and I admit it can be quite
frightening) and work his way out from the ridge then some fantastic altitude
can be gained, enabling dynamic manoeuvres such as 360s and "figure of eights"
to be safely undertaken. Eventually, however, the lift peters out and, losing
height, it is again necessary to fly back into ridge lift.

With this spell of hot weather we have been having, my friend Bob Calvert and I
have had more than our fair share of this type of flying. On one notable day,
we were soaring a small 150 foot local ridge in a 22 mph wind with clouds
forming on the other side of the valley 3 miles away which, when they arrived,
often hefted us up to about 1,000 feet. After realizing what was happening we
patiently buzzed up and down the ridge waiting for the next cloud to come so we
could, hopefully, catch its thermal. It must have been amusing (and surprising
on such a small ridge) to see first one kite and then the other pop up to
become just a small triangle in the sky, and then when it came down again, the
other.

Probably the most exhilarating moment came, however, when we both hit the same
thermal and ended way up there in the blue sky, side by side, with 100 feet
between wingtips and at some mutual understanding, suddenly pulled into two
simultaneous tight turns, myself cranking off rapidly to the left, and Bob to
the right. It must have looked good from below! Incidentally, all this occurred
during one flight in which Bob set a new Pennine HGC soaring record of 2 1/2
hours (which has already been broken). At this point I would also like to
mention Phil Robinson and his girlfriend Linda, and Paul Adams, who were aloft
with us, not forgetting our unfortunate friend William Jones who broke his arm
hang gliding.

These experiences have made me wonder about further possibilities in hang
gliding. Until now my most enjoyable flying has been soaring on the many ridges
we have around here. Although the experience (as you would know) is incredible,
I sometimes feel a little bit imprisoned by the fact that I must stay in a
relatively narrow air space in order to maintain lift, and watch the same piece
of ground sliding slowly beneath my feet. I must admit I have been looking for
a free-er form of flying, and now perhaps I've found it! Certainly after my
recent thermalling experiences I have felt that more freedom is possible by
gaining height in a thermal and then flying cross-country. I was very excited
by an article in the American magazine, "Ground Skimmer" by Chris Price who was
thermalling in the Arizona desert and flying from ridge to ridge and thermal to
thermal.

Of course I realize that in our country such flights would be carried out on a
much smaller scale. But after seeing one friend gain probably 1,600 feet of
height and having myself shared the air with a conventional glider at Hay Bluff
at an altitude which my friend (who was on the ground) and I reckoned to be in
excess of 2,000 feet (and that's no exaggeration, I swear), I am fascinated
with the idea of using this height to eat up the miles.

Probably there are people who would say that thermal flying is too dangerous
because thermals are unpredictable and turbulent and as such, flying them
should be discouraged, particularly now that the public eye is on us more than
ever. My only answer to this is, ironically, another question: why do you fly
hang gliders? Think about it and see if you can blame some of us for
adventuring. You might think it's a little weak, but it's all the answer I
need...

This was written in July, 1975, in a magazine that also carried articles on how
to make a 360 degree turn without hitting the hill, as I had done on my first
attempt, and an account of Dick Bickel being towed across the English Channel
flying a tow-kite behind a motorboat; no advance at all on Bill Moyes ten years
earlier.

This is not meant to be a how-to account of hang-gliding, but it is necessary
to explain a little about the air we fly in. Like all gliding aircraft, hang
gliders will always descend through the air at a speed called sink-rate. In
early rogallos, the sink-rate was often higher than 500 feet a minute. As hang
gliders developed, sink-rates dropped close to 200 feet/min. If gliding
aircraft are always going down, how do they go up? Simply by finding air that
goes up quicker than the wing goes down. Such air is called "lift".

There are at least three standard forms of lift. The first, which Graham Hobson
called "ridge lift", is when the wind meets a hill and rises over it, creating
a band of air which can sustain wings. Birds, gliders, hang gliders and
paragliders can take off into this lift band, and go up. In pre-historic times,
Pteradactyls were thought to have used ridge lift to fly up and down looking
for prey below. It is much like a ping-pong ball riding on a jet of water. So
long as the air goes up faster than the aircraft descends, the aircraft will
stay up. But the aircraft has to remain within the lift band.

The second form of lift is the so-called thermal that Hobson discovered, as it
were, by deduction. Thermals are caused by the sun heating the earth, and the
earth heating the air above at different rates; a brown field will heat up
quicker than a green field. The air above the brown field also heats up
quicker, and when the temperature difference between the brown field's air and
the surrounding air is great enough, the bubble of warmer air breaks off and
starts to rise. The rate it rises depends on the change in temperature with
height (called the 'lapse rate'). This bubble is doughnut-shaped, with a column
in the middle rising quickly - the core of the lift - and a turbulent outer
layer called 'sink'. When the bubble rises high enough, the moisture it carries
turns into cloud (a cloud doesn't have a thermal, it is where a thermal ends
up).

If one heat source is constantly pumping out thermals then a line of clouds
forms down-wind, fed regularly by the heat source. This is called a
cloud-street. I cannot resist telling you that the best lift is found on the
sunny side of the street.

The third form of lift is called 'wave', described in more detail in the Icaras
and Daedelus story. But we did not know very much about wave in 1976, until
there was another letter to Wings! magazine, this time from another northern
pilot called Paul Maritos, with information from the same Graham Hobson who
asked what a thermal was...

…Monday afternoon, 5th April, saw the Birdman Competition drawing to a pleasant
conclusion with the presentation of the trophies and a succession of farewells.
One by one each flyer had a last soar along the ridge and then leisurely
de-rigged and departed in the breeze and sun of an afternoon more like August
than April.

Eventually only two kites were left, my Vynair and Graham's Skyhook. By 4
o'clock we had had our fill, Graham had landed, arms aching from the turbulence
and complaining of hunger. He reckoned that was his lot for the day. I borrowed
his helmet and decided to have my last session too. We carried my glider to the
edge and, apprehensively, I decided to fly, uncertain that I would penetrate a
wind now blowing 30 mph on a relatively small ridge.

My first reaction on take-off was incredible relief as the sail went fairly
quiet and I went slowly but steadily up and out. There was some rough air about
from thermals, but it wasn't too bad. Gradually I found myself getting into the
habit of waiting for a thermal to take me up to about 500 feet, do a 360 or two
and wait for the next one, just like waiting for a bus!

Anyway, Graham saw all this going on and I knew he'd be up there sooner or
later, with or without his helmet! (I had lost mine the day before). About this
time the lift was becoming smoother and I was going higher. When Graham took
off, all I could see of him was a tiny kite scooting back and forth along the
ridge, and I thought how mad he would be if he didn't gain any height. Next
time I looked he had gone, and then I saw him in line with the sun and above
me!

It really was incredible. For nearly an hour we could go anywhere within an
area of about a half mile square at a height of 1,000 to 1,500 foot, gently
searching out the edges of the lift. The smoothness was out of this world.
Talking about it afterwards we both found that we'd had time to "tweak" the
rigging wire - feeling the tension, or lack of it - and to fly hands-off.

It was quite an experience and a search through the conventional gliding books
in the library put things into perspective. We had happened to be in the air
when conditions had just been right for, we think, a combination of ridge lift
and wave lift at that particular place.

"Wave lift" describes a situation where the air flow, having risen over a hill
or ridge and fallen in the lee of it, continues to repeat this pattern, up and
down, as it travels along for some distance downwind, so forming waves of
rising and falling air. This is quite likely after a day of steady winds.
Perhaps what happened to us was that for one hour the "upsweep" of a wave from
one of the hills upwind of us had coincided with the normal ridge lift. We'd
gone high, for us, but to put things into perspective a conventional glider in
the same place might have gained 10,000 feet and not just 1,000 feet. Roll on
the day when kites can do that...

... [Continued next week]
============= End of Chapter V, Part 1 ==============