﻿AERONAUTIC 
  RESEARCH 
  — 
  AMES. 
  

  

  171 
  

  

  be 
  made 
  to 
  revolve 
  rapidly 
  in 
  a 
  horizontal 
  plane. 
  Others 
  have 
  

   studied 
  models 
  of 
  different 
  shapes 
  by 
  dropping 
  them 
  from 
  heights 
  

   inside 
  buildings, 
  so 
  as 
  to 
  avoid 
  wind. 
  

  

  Air 
  Stream 
  

  

  Anqle 
  of 
  Attach 
  

   Fig. 
  4. 
  — 
  Diagram 
  illustrating 
  forces 
  acting 
  on 
  an 
  aerofoil. 
  

  

  Owing 
  to 
  the 
  importance 
  of 
  wind 
  tunnels, 
  I 
  have 
  introduced 
  plates 
  

   4 
  and 
  5, 
  which 
  show 
  some 
  -photographs 
  of 
  the 
  latest 
  one 
  made 
  in 
  this 
  

   country, 
  that 
  of 
  the 
  National 
  Advisory 
  Committee 
  for 
  Aeronautics 
  

   at 
  the 
  Langley 
  Memorial 
  Laboratory, 
  Langley 
  Field, 
  Va. 
  

  

  Fig. 
  5. 
  — 
  Diagram 
  of 
  wind-tunnel 
  in 
  its 
  house. 
  

  

  Investigators 
  in 
  these 
  different 
  laboratories 
  all 
  over 
  the 
  world 
  

   have 
  studied 
  the 
  greatest 
  variety 
  of 
  problems 
  — 
  forces 
  on 
  models 
  of 
  

   wings 
  of 
  different 
  shapes 
  at 
  different 
  air 
  velocities, 
  forces 
  on 
  models 
  

   of 
  airships, 
  the 
  effect 
  of 
  disturbing 
  elements 
  on 
  these 
  forces, 
  etc. 
  A 
  

   long 
  series 
  of 
  investigations 
  has 
  been 
  made 
  in 
  particular 
  upon 
  air 
  

   propellers. 
  The 
  blade 
  of 
  a 
  propeller 
  may 
  be 
  considered 
  as 
  made 
  

  

  