﻿SOATvING 
  FLIGHT 
  KLEMPERER 
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  the 
  storm 
  for 
  a 
  safe 
  landing. 
  The 
  whole 
  flight 
  had 
  lasted 
  three- 
  

   quarters 
  of 
  an 
  hour. 
  According 
  to 
  his 
  own 
  account, 
  he 
  must 
  have 
  

   had 
  a 
  thrilling 
  time 
  when 
  he 
  was 
  bounced 
  about 
  by 
  the 
  violent 
  

   cross 
  currents 
  in 
  that 
  aerial 
  whirlpool, 
  visibility 
  at 
  times 
  completely 
  

   extinguished 
  in 
  the 
  dense 
  mass 
  of 
  turbulent 
  foam. 
  There 
  is 
  no 
  

   doubt 
  about 
  Herr 
  Kegel's 
  ability 
  as 
  a 
  pilot, 
  but 
  it 
  may 
  be 
  men- 
  

   tioned 
  that 
  he 
  had 
  also 
  built 
  his 
  machine 
  himself 
  in 
  his 
  spare 
  time 
  

   and 
  it 
  was 
  one 
  of 
  outstanding 
  efficiency 
  and 
  workmanship, 
  too. 
  

  

  There 
  is 
  some 
  advantage 
  in 
  flying 
  in 
  adverse 
  weather. 
  Quite 
  

   a 
  number 
  of 
  spectacular 
  soaring 
  flight 
  events 
  were 
  indeed 
  distin- 
  

   guished 
  by 
  rather 
  unsettled 
  weather 
  conditions. 
  The 
  stormier, 
  the 
  

   greater 
  the 
  chances 
  for 
  reaching 
  high 
  altitudes. 
  Gliders 
  have 
  often 
  

   climbed 
  1,000 
  feet 
  above 
  the 
  crest 
  of 
  the 
  mountain. 
  Since 
  1921 
  

   the 
  gliders 
  were 
  out 
  in 
  any 
  weather 
  up 
  to 
  gales 
  of 
  45 
  miles 
  per 
  hour. 
  

   Only 
  a 
  dead 
  calm 
  would 
  confine 
  them 
  to 
  idle 
  w^aiting. 
  What 
  a 
  

   difference 
  from 
  the 
  state 
  of 
  affairs 
  during 
  the 
  early 
  days 
  of 
  motor- 
  

   driven 
  aircraft. 
  No 
  airman 
  will 
  deny 
  that 
  learning 
  how 
  to 
  buck 
  

   gales 
  immediately 
  close 
  to 
  mountain 
  ridges 
  constitutes 
  a 
  very 
  valuable 
  

   training 
  for 
  meeting 
  unexpected 
  aerial 
  situations. 
  

  

  In 
  a 
  flat 
  country, 
  even 
  in 
  the 
  absence 
  of 
  meteorological 
  dis- 
  

   turbances, 
  vertical 
  currents 
  may 
  be 
  induced, 
  for 
  instance, 
  at 
  the 
  

   border 
  line 
  of 
  a 
  smooth 
  and 
  a 
  rough 
  surface. 
  Imagine 
  the 
  wind 
  

   blowing 
  over 
  a 
  great 
  grassy 
  plain 
  or 
  a 
  great 
  body 
  of 
  shallow 
  water, 
  

   then 
  striking 
  an 
  adjacent 
  forest, 
  the 
  trees 
  of 
  which 
  obviously 
  absorb 
  

   more 
  energy 
  per 
  unit 
  of 
  area. 
  The 
  friction 
  layer 
  in 
  which 
  braking 
  

   impulse 
  is 
  transmitted 
  will 
  here 
  extend 
  higher 
  than 
  above 
  the 
  smooth 
  

   plain. 
  The 
  retarded 
  air 
  has 
  no 
  other 
  escape 
  but 
  upward 
  deflection. 
  

   Havens 
  and 
  buzzards 
  can 
  sometimes 
  be 
  seen 
  soaring 
  a 
  short 
  distance 
  

   leeward 
  of 
  such 
  border 
  lines 
  of 
  surface 
  roughness. 
  

  

  When 
  one 
  only 
  temporarily 
  happens 
  to 
  find 
  profitable 
  upward 
  

   currents, 
  it 
  is 
  obviously 
  best 
  to 
  concentrate 
  production 
  of 
  lift 
  during 
  

   these 
  favorable 
  periods, 
  by 
  rising 
  or 
  by 
  storing 
  kinetic 
  energy 
  in 
  

   order 
  to 
  gain 
  some 
  reserve 
  to 
  draw 
  upon 
  while 
  negotiating 
  the 
  lull. 
  

   In 
  fact, 
  the 
  wind 
  is 
  almost 
  never 
  like 
  a 
  viscous 
  stream. 
  It 
  contains 
  

   turbulence 
  and 
  there 
  is 
  something 
  like 
  one-third 
  of 
  the 
  chances 
  for 
  

   the 
  occurrence 
  of 
  vertical 
  turbulence 
  components. 
  Fortunately, 
  the 
  

   mere 
  inertia 
  causes 
  any 
  airplane 
  to 
  gain 
  from 
  such 
  vertical 
  pulsa- 
  

   tions 
  a 
  slight 
  increase 
  in 
  lift 
  or 
  a 
  slight 
  reduction 
  of 
  drag. 
  Katz- 
  

   mayer, 
  in 
  Vienna, 
  proved 
  this 
  by 
  model 
  experiments 
  in 
  the 
  wind 
  

   tunnel, 
  introducing 
  artificial 
  cross-wind 
  pulsations. 
  The 
  theoretical 
  

   explanation 
  of 
  the 
  phenomenon 
  is 
  this: 
  Any 
  upward 
  fluctuation 
  

   causes 
  the 
  relative 
  air 
  stream 
  to 
  strike 
  the 
  wings 
  at 
  some 
  inclina- 
  

   tion 
  upward, 
  thereby 
  inclining 
  the 
  resultant 
  air 
  force 
  forward. 
  In 
  

   the 
  descending 
  phase 
  of 
  the 
  fluctuation 
  the 
  reverse 
  holds, 
  thus 
  in- 
  

  

  