From: unimelb@peg.pegasus.oz.au
Newsgroups: aus.aviation
Subject: Joys of Open Cockpit Navigation
Date: 27 Aug 92 14:42:00 GMT
Nf-ID: #N:peg:511500004:000:6190
Nf-From: peg.UUCP!unimelb    Aug 27 09:42:00 1992


The Joys of Open Cockpit Navigation - Coldstream to Robe in a
Tiger Moth by Stuart Hawkins (VH-HSH)

The Tiger Moth offers some interesting challenges for
cross-country navigation.

Firstly, the open cockpit provides rather more than a steady
breeze around your head, with some eddies finding their way down
to your knees. I mention the knees because they are convenient
fixtures on which to balance maps and flight plans - the catch is
that if these are not tied down in some way they have a disarming
habit of disappearing into the ambient slipstream.

Secondly, the aeroplane, having no electrical system, usually has
no radio or navigation aids. A thumbs up on take off and the
occasional waggling of wings are about the extent of meaningful
signals. Some cynics think that IFR in aircraft of this vintage
means I follow railways.  This is not true in VH-HSH. She has a
couple of excellent compasses which, when combined with a sundial,
an hour glass and a parchment scroll showing where the buried
treasure lies, give all the guidance you need. But I take
liberties with the truth. In fact, the conventional World
Aeronautical Chart is essential - the challenge is how to hold,
fold, unfold and read it without losing it or getting yourself
tangled up in it. It must be read well below the level of
windscreen or cockpit hatch. However, as soon as you put your head
down, thus taking your eyes off the horizon, the Tiger develops a
mind of its own, usually with a mild spiral dive as the outcome.
So progression from Point A to Point B becomes a series of
ungainly staggers or wallows until you develop the art of holding
the stick between your knees while keeping the right amount of
rudder pressure on the pedals, and of pulling off your gloves with
your teeth while holding a protractor on the chart with the other
hand. Oh for one of those Indian deities with six arms!

Thirdly, there is endurance which is of two kinds - fuel and
bladder. The basic Tiger holds 19 Imperial gallons in an overhead
tank, and burns off six per hour, thus giving you slightly more
than three hours cruise, or two and a quarter allowing for the
mandatory 45 minute reserve. I have a standard modification in the
form of a 10 gallon reserve tank which fits under the front
instrument panel. Fuel is transferred by a wobble pump on the
right-hand side of the pilot's seat in the rear cockpit. Mine
requires 500 strokes to transfer all the fuel to the top main, a
tedious job usually effected in five lots of 100 strokes. The
pumping motion also may add to rocking movements in the
horizontal plane as the pilot changes hands to hold the control
column with left hand while pumping with the right. It must look
to a casual passer-by that the plane is doing a series of small
bunny hops!

The second component of endurance is well known to all distance
fliers. Flight shops at major airports have various devices to
capture the product. Hence it should be plain sailing, so to speak
- except that the open cockpit can be cold, d--n cold. And cold,
coupled with Gipsy Major-induced vibrations, invariably stimulates
the kidneys. Hence at the end of a longish flight I tend to
clamber out of the machine with thoughts only of the fastest
pathway to relief. The best laid plans can go astray, especially
when on arrival at some distant airfield admirers of fine
heavier-than-air machinery ply you with questions about  keeping
the old dears airborne. The latest smart reply is because it has
three inch rather than one and a half inch rib stitching on the
wings.

Finally, there is the clothing. While the reserve tank makes three
to four hours in the air a real possibility, long flights are best
conducted in temperate conditions lest you seize up.

Earlier this year I flew from home base at Coldstream on the north
eastern side of Melbourne to Robe on the lower south-eastern coast
of S.A., with an overnight stop at a Kingower winery near
Wedderburn - purely for oenological interest I might add. For the
second and main leg of my flight from Wedderburn to Robe I had 20
knot head winds,  a TAS of 70 knots and a track of 235 nautical
miles. Despite being mid summer in southern Australia, we were
enjoying the coldest January in recorded meteorological history -
it must have been 10 degrees C. or lower at 3000 feet. Even with a
thermal vest and 'long johns', a genuine woollen guernsey, a
leather jacket, the mandatory scarf  and a pair of Oshkosh
insulated overalls I arrived at the Robe grass strip looking like
an iced version of the Michelin tyre advertisement. As I was
gingerly straightening partially seized joints while hauling
myself out of the cockpit a curious bystander wandered over and
asked me what sort of plane it was. "What do you think it is?" I
replied, only to be flabbergasted by his reply: "A Spitfire?"
Despite mounting pressure down below this was a golden opportunity
to practice my teaching skills: "Well no, not quite - its a Tiger
Moth". "How old is it?" the ignorant one asked. More facts - 1931
design,  assembled in 1942 at Mascot by De Havilland Aircraft Pty
Ltd under contract to U.K. Air Ministry.  Constructor's Number
817.  Assigned R.A.F. serial  DX760, for use in South
Africa/Rhodesia, but not delivered.  Held in bond storage. Brought
on charge by the R.A.A.F. in 1943 as A17-667, etc. Then the
crunch: "And how old are you?"; "How old do you think?"; "Aw,
about 70!" That was it - out of the cockpit and out of my gear as
fast as I could, and a quick trip behind the sheltering tail
feathers to ease back pressure on the personal plumbing.

The return to Coldstream was a breeze, literally. A nice high
pressure system with winds light to variable. This time I tracked
to Hamilton for a refuelling stop, direct to the Heads at the
southern end of Port Phillip Bay, and up the coast to Dromana
before heading more or less due north to the field. An incredible
view of the Western District plains just about as far as I could
see in any direction. Navigation no problem in conditions like
this. As long as you keep the sea to your right, aim at Mount
Elephant, and keep on trackin'. One of those days that makes it
impossible for you to kick the Tiger habit.
Newsgroups: aus.aviation