News release: 6 Mar 25,280 ft
Successful tow today to 25,280 ft!
It takes quite a long time to prepare for as high altitude flight! Up
at dawn, we were ready for takeoff at 10:30.
The early morning meterological briefing by the Italian Air-Force
indicated we had only a very limited window this morning before a warm
front brought rain and low cloud in from the Tyrenanean sea. The
forecast for Sunday is appalling and these two days are the only ones
available for us to climb above 10,000 ft. Conditions not ideal, stratus
at 8,000 ft and alto-stratus at 20,000 ft, with a forecast -52 deg at
30,000 ft. but from the ground we could see some blue sky.
Fully loaded with fuel and oxygen, the launch seemed long but we soon
settled down to a climb of about 450 ft / min at 4800 rpm. Flight plan
is to climb to 10,000 ft above Guidonia and then head NE about 45 Km in
a 5 NM wide corridor with a ceiling of FL 240 to the Rieti zone where we
are cleared to max FL 320.
The Brauniger vario LCD display disappeared first at about FL 150 at
-20c, as we passed through the Alto Stratus at FL200 we picked up quite
a hoarfrost on all metallic parts and notably on our visors. the
Volkslogger flight recorder display disappeared at FL 220 and -30 c and
about this time Richard dropped his map overboard when the bungee
securing it lost its elasticity and some plastic part in his PTT switch
failed which made further communication with Rome Information
impossible, the transponder battery probably froze at about this time
too. Fortunately, in a sea of white, the city of Rieti, and its glider
airfield, set in a bowl in the snow-covered Apennine mountains remained
in view in a Fohn 'hole' otherwise the flight would probably have had to
be aborted there and then.
Climbing still at 250 FPM through FL 250 and -40 deg C, Angelo noticed
he was actually flying in a very distinct 'vapour trail' created by the
tug! He also began to suffer an extreme build-up of ice on the
exhalation valve of his mask and with safety in mind, decided to
release.
With a dead GPS, broken PTT switch and no map Richard descended rapidly
to land at Rieti, Angelo headed back to Guidonia but landed in a field 2
Km short of the field.
So what did we learn?
Basically the flight was a great success. The Pegasus Quantum 914 XL
tug was still climbing very strongly (250 FPM @ FL 250) and looks easily
good for the target of 30,000ft over Everest. A small adjustment to the
pitch of the excellent Warp Drive propeller may actually improve this
rate of climb, above FL 250 Richard had to throttle back quite
substantially to maintain 5,600 RPM. The Bailey Aviation intercooler
was definitely working very well, manifold temperature was approximately
ambient throughout the flight.
Angelo needs more protection from the cold around his mask, and maybe a
heater of some kind on the exhalation valve to break away any
substantial build-up of ice. Richard has a neoprene 'baffle' over his
entire mask except the exhalation valve and suffered no ice problems in
the mask or oxygen system, but will not be wearing dark glasses in
future which froze over as they passed through the alto-stratus giving
him a very restricted view of the world!
The Gerbings heated clothing, gloves and socks, and 'The North Face'
suit protected Richard very adequately from the cold, but the mittens,
though very warm, went unmanageably stiff below -30c, good bar-mitts may
well be a better solution.
Angelo was also comfortable in his 'The North Face' suit but got cold
hands and feet. Better bar mitts and Gerbings heated socks and gloves
(which we have, but he did not use) should be the solution.
The quantities of fuel and oxygen we were carrying will definitely be
adequate for Everest flight but with so much clothing, mask Etc. it is
impossible to physically view the fuel level or oxygen pressure in
flight, better indicators for both of these need to be fitted before
departure to Nepal. Angelo also needs some sort of remote O2 pressure
gauge.
The video recorders on both aircraft worked well but picked up a lot of
frost on their lenses when passing through the cloud. This should not
be a problem in Nepal as we simply won't be flying there in such
marginal conditions.
Finally, it was known, but not fully appreciated, that LCD displays are
completely useless in extreme cold, both altimeter displays failed on
the tug and it will be necessary to carry at least an analogue altimeter
(though the Rotax FLYDAT display continued to function perfectly,
probably because the main battery inside the instrument pod has a NELTEC
heater on it and the display itself effectively has double-glazing).
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