fpff CROSS-COUNTRY SOARING A HANDBOOK FOR PERFORMANCE AND COMPETITION SOARING HELMUT REICHMANN THOMSON PUBLICATIONS Copyright ® 1978 by Thomson Publications a division of Graham Thomson Ltd 3200 Airport Avenue Santa Monica, California 90405 All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the Publisher. First Printing 1978 Library of Congress Catalog Number: 77-86598 TO OUR FRIENDS who helped and encouraged us when the finish gate seemed so far away Paul Bikle Hannes and Connie Linke Bud Mears ERRATUM Copyright statement is amended to include: "Translation of the book Streckensegelflug by Helmut Reichmann, published by Motorbuch- Verlag, Stuttgart. Copyright Motorbuch-Verlag, Stuttgart, 1975". FOREWORD Surely, man's age-old dream of flying has found its Many of these relationships are simple and easy to purest and most beautiful expression in soaring. Na­ comprehend; others are quite complex in their ramifi­ ture opens up to the soaring pilot a world that would cations, and lead to whole chains of logic that can have been thought unreachable only a few years ago play important roles in cross-country flight. This is the a world of mighty forces, gentle or wild, majestic reason that there isn't any single secret to winning and mysterious. The pilot enters this realm, flies in it, competitions or making long flights, even though makes use of its dynamics, and tries to explore and some pilots still seek such a philosopher's stone. fathom its mysteries. The burden of everyday life is There's a tremendous number of factors that must be left on the ground and becomes inconsequential considered, weighed as alternatives, and used to compared to the freedom that the wings of a make a decision. If the most important of our soaring sailplane can provide. decisions are successful ones, we have a good The better we understand nature, the more adroitly chance for success, even if it's impossible to make all we can make use of her powers to fly higher, farther, decisions completely correctly. and faster. The characteristics and performance of It is quite common at large contests for top pilots to our sailplane set the bounds of our possibilities; we gain or lose large distances among one another, only "feel" some things almost instinctively, while others to meet once again when crossing the finish line. must be laboriously learned and practiced. Our Obviously each pilot has made different mistakes, but bodies are called upon to function under stresses for the end result remains the same. If it were really which they were not designed; our minds must con­ possible for a pilot to make optimum use of the stantly assimilate new situations, weigh new factors, weather and the properties of his sailplane, he would and make decisions. probably do 10 to 20 per cent better than even There are probably few other sports in which suc­ current world champions. cess requires not only good physical condition, but The quality of the good pilot, then, is largely that of also correct recognition of natural processes a fact making somewhat fewer or less serious mis­ which makes soaring a very special sport indeed. takes than others. Heinz Huth had that in mind when The soaring flights of today, which would have he told a reporter who asked him about his "secret," appeared impossible some years ago, are due only "Well, the others let me win." I wonder if the reporter in part to the improved aerodynamics of modern really understood what he meant? sailplanes. The development of the aircraft over the If this book helps you to understand more of the last 15 years has been as rapid and visible as it has factors that influence your soaring, passes on some been successful. The development of flying, of tactics competition experience, and thus leads to better de­ and techniques, while perhaps not so obvious, has cisions, it will have added to the joy of our sport and been equally important, if not more so. Mastery of the have fulfilled its goal. sailplane itself, that "feel" for its controls that used to Helmut Reichmann be so highly prized among top pilots, has become merely another pre-requisite for performance soaring. It's true that talent still plays a role, but talent alone is no longer sufficient it must be linked with a great TRANSLATOR'S NOTE: deal of knowledge and practice. Talent and practice complement one another to some extent: the talented Some of the crew techniques described in the origi­ pilot may not need as much practice. There is no nal particularly those relating to the crew's pro­ substitute, however, for knowledge. In today's cross­ ceeding ahead of the pilot and advising him of condi­ country flying, for example at contests, a pilot must tions, or making wind measurements, etc. are have a good grasp of the theoretical basis on which standard only outside the USA, notably at world his techniques and tactics are grounded, if he wants championships. to have any chance of winning. These theories cover Use of such techniques in other local, regional, or a good deal of meteorological knowledge, as well as even U.S. national competition is not only considered somewhat more limited areas of mathematics and unsportsmanlike at present, but may actually be physics. cause for disqualification. OVERVIEW It would seem reasonable that the soaring pilot is primarily interested in the "How," and only later in the "Why," of distance soaring. In order to avoid overwhelming the reader at once with diagrams and formulas, this book has been divided into two parts: PART I: FLYING PRACTICE AND TECHNIQUES PART II: THEORETICAL SECTION provides the contains the information the pilot should have in basis for Part I and can serve to increase the order to participate successfully in distance soar­ depth of comprehension of the material al­ ing for badges or for competition. In addition to together. It also includes individual points which practical suggestions a certain amount of basic are considered essential to a complete under­ theory is included when unavoidable for complete standing of the problems of modern soaring. The understanding, and when it can be presented in a division of this part into individual sections is relatively simple and compact form. based largely on that of Part I, so that direct correlations can be made between theory and Flight in Lift..... ........................ 1 practice even when they are not specifically Navigation .................................. 38 pointed out in Part II. Landing Out .............. ................. 49 Speed-to-Fly ........... ................ 56 Meteorology .... .......................... 82 Physical Conditioning ........................ 65 Speed-to-Fly ............ ................... 95 Competition Tactics.......................... 66 Equipment ....... ....................... 124 Training and Conditioning .................... 71 Equipment .................................. 75 TABLE OF CONTENTS PART I: FLYING PRACTICE AND TECHNIQUES Flight in Lift Searching for thermals at medium altitudes .. 16 Life cycle of cumulus in moist SLOPE SOARING surrounding air 18 Eddies upwind of steep slopes Flying tactics under stratocumulus 19 Climb upwind of, or over the summit Life cycle of large cumulus Importance of upwind terrain .... or towering cumulus ... ..... 19 Conical mountains are unsuitable Searching for thermals below Long, low ridges .................. cumulus congestus ............ 21 Venturi effect ..................... Convective thunderstorms 21 Airspeed variation ......... Line squalls, frontal thunderstorms 21 Never consider slope lift in isolation Thermal lines and cloud streets 21 THERMAL SOARING ............................ 3 Flying tactics for thermal streets 22 Flight along a thermal street 22 Thermal sources ........ .......... 3 Circling is more likely to be worthwhile if 24 Lighter if warmer or moister ............. .... 3 Optimum flight under cloud or thermal streets 24 A poor conductor of heat ...... 4 Courseline oblique to the thermal street 25 The surface not the sun heats the air ... ... 4 Use in flight .. ...... ..... 25 Formation of unstable surface air ... ............ 4 Optimum departure angle ........ 26 Solar energy (insolation) ... ........ ...... 4 Optimum triangle flight under cloud streets .. 26 Dependence of surface heating on surface character 4 Energy transfer time from ground to air .. .... 5 Flight in cloudless area 26 Instability due to moisture differences ...... 5 Industrial thermals 27 Take a mental stroll .... 5 Thermals without condensation 27 Where are thermals triggered? 5 Flying "blue 1 thermals .... ...... 27 Triggering impulses in calm air . 6 Triggering impulses in wind .... 6 Airflow over convective barriers 28 Searching for thermals at low altitude 6 Convective "slope" lift , , ... 29 About birds .......... 7 Thermal street waves .......... ..... 30 In zero sink ... .. ........ 7 Flight in convective waves ........... .... 30 On calm days ... 7 Trains of thought .. .... 7 INVERSION AND SHEAR WAVES (MOVING Hilly terrain ........ 7 WAVES) 30 Safety when circling at low altitude .. 8 LEE WAVES IN MOUNTAINOUS TERRAIN . 31 Entering the thermal Development of lee waves 31 Terrain influence .. 32 Centering and flight in the thermal 9 Weather requirements 32 Three centering methods 10 Flow model of lee waves 32 Importance of clean flying while thermaling 11 Clouds are not indicative