KRONFELD ON GLIDING AND SOARING.pdf - Lakes Gliding Club

MY SOARING FLIGHTS IN ENGLAND 373
The best times flown after casting off were those of Groenhoff
and Hirth with one hour forty-two minutes and one hour
twenty-seven minutes respectively, whilst I, who started
later, followed with one hour ten minutes. I landed,
in accordance with the rules, as the only one above
the prescribed height of eight hundred and in a radius
of one kilometre. It would be quite conceivable that even
if only a few engined machines were available, such a
contest could be carried out in such a manner as to give
a scale on which performances could be judged correctly.
It would only be necessary to tow the machines starting
first to a higher altitude corresponding to their sinking
speed, so that all the planes at a predetermined time were
at a certain height, from which time onward the flying
time only would be appraised. It will be absolutely
impossible, on account of the varying heat at different
hours of the day, to obtain an equal scale for all the
machines.
Probably, the most interesting performances of the contest
were the distance flights utilizing the heat. The flights
over the large towns in the spring of last year, my first
distance flights over level terrain in London, my last two
flights to Oechsen and the towed flight contest had all, more
or less, been thermal flights. The performances put up
on August 2nd, among which the high altitudes, already
mentioned, attained by the practice pilots and above all
by Hakenjos are also included, belong likewise to this newest
field of gliding flight. On August 2nd, we had weather
conditions very rare in the Rhon district. Particularly hot
weather and exceedingly strong east winds prevailed.
Groenhoff was the first to disappear after he had reached
a high altitude. Hirth started later and quite a considerable
time elapsed before he was successful in working his way
up high in a thermal current. At approximately seven
hundred feet he was able to escape from the Wasserkuppe
mountains and he circled up in spirals to two thousand feet.
Thermal gliding is only possible by continued circling in
an up-current and it is therefore obvious that during this
time, one drifts in the direction of the wind. When Hirth
had reached this high altitude he found himself about