6 THE Ki th* watch 1 recuir CU IDe S thumb rw sec n 1 tal t thro weqi estirr oiIii Ix Ii- 182 IN oz 3 LBS craft oss sec lOT CC corrections terminal velocity model claimed least 2742 mph suspect slightly higher addition timing system used 1976 primary system used 1977 fully automatic photocells detect passage airplane same kind equipment used inter national racing events 40-foot-wide bank photocells located end 50-meter measured course bank consisted eight Heuer HL 2-21 di rectional photocells pointed upward Ad jacent photocells spaced less wing span apart plane flew over narrow-beam photocells triggered two banks photocells connected Heuer HL 305 timing computer printed elapsed time 1/1000 second elaborate system provided superb accuracy solving timing problem latest technology expensive requires careful alignment also makes flying demanding since course 40 feet wide wider course permitted FAI would have required photocells orient pilot difficult task flying through narrow corridor yellow ribbon ground extended far beyond measured course flying site 6600 feet above sea level Normal air density altitude 19% lower sea level allowing 9% higher terminal velocity Sitar Fritz used same design 1977 before increased its weight 30% raised terminal velocity 14% also climbed much higher 1976 height determined two meth ods wing span carefully measured frames movie film taken start DIVE PROFILE Drop Speed Speed Increase Feet MPH MPH/sec 047084680210 199883203 3431077194 5151261184 7121433172 9341593160 11791740147 14441874134 1 7281996122 20292106110 2345220599 2675229388 3017237178 3370244069 3733250161 4103255453 compared other frames known distances along ground measurements showed altitudes test flights 1800 feet over 4000 feet second method used indicate height time dives stopwatch record dives times 148 153 seconds Knowing approximate aircraft terminal velocity altitude can determined table shows calcu lations dive Pfeil P731 assuming its terminal velocity 291 mph cluding combined effects constant gravity increasing drag starting speed 47 mph normal level flight speed fifteen seconds after start dive model has descended 3733 feet traveling 250 mph calcu lated time speed good agree ment measured values record project undertaken organization Innsbruck Austria known Arbeitsgemeinschaft Model segelfiug Entwicklung working group model sailplane development Its techni cal leader Fridolin Fritz its pilot Werner Sitar evidently several other members group difficult brief article convey great care took aspects flight proj ect full story requires 78 pages dossier have seen other dos siers demonstrates magnitude effort approaching expended Austrians sailplane speed record Theirs thoroughly professional job doubt its authenticity can sailplane fly faster powered model Because has less drag prop engine pipe limit speed attainable powered dive ap pendages actually use power produce near end long dive Gravity supplied about 25 horsepower Austrian model bottom its dive Can record beaten think can major effort aspect flight must optimized will require expert dedicated group flying model high altitude sur face loading near maximum allowable FAI rules2457 oz/sq ft fliers mountain states get started 10 Model Aviation Pfeil Arrow displayed Brand Electronic Microprop Nurnberg Show picture taken Ron Moulton background photo showing large team supported Austrian record-breaking effortthe mountainous terrain looms behind them
Edition: Model Aviation - 1978/08
Page Numbers: 8, 9, 10
6 THE Ki th* watch 1 recuir CU IDe S thumb rw sec n 1 tal t thro weqi estirr oiIii Ix Ii- 182 IN oz 3 LBS craft oss sec lOT CC corrections terminal velocity model claimed least 2742 mph suspect slightly higher addition timing system used 1976 primary system used 1977 fully automatic photocells detect passage airplane same kind equipment used inter national racing events 40-foot-wide bank photocells located end 50-meter measured course bank consisted eight Heuer HL 2-21 di rectional photocells pointed upward Ad jacent photocells spaced less wing span apart plane flew over narrow-beam photocells triggered two banks photocells connected Heuer HL 305 timing computer printed elapsed time 1/1000 second elaborate system provided superb accuracy solving timing problem latest technology expensive requires careful alignment also makes flying demanding since course 40 feet wide wider course permitted FAI would have required photocells orient pilot difficult task flying through narrow corridor yellow ribbon ground extended far beyond measured course flying site 6600 feet above sea level Normal air density altitude 19% lower sea level allowing 9% higher terminal velocity Sitar Fritz used same design 1977 before increased its weight 30% raised terminal velocity 14% also climbed much higher 1976 height determined two meth ods wing span carefully measured frames movie film taken start DIVE PROFILE Drop Speed Speed Increase Feet MPH MPH/sec 047084680210 199883203 3431077194 5151261184 7121433172 9341593160 11791740147 14441874134 1 7281996122 20292106110 2345220599 2675229388 3017237178 3370244069 3733250161 4103255453 compared other frames known distances along ground measurements showed altitudes test flights 1800 feet over 4000 feet second method used indicate height time dives stopwatch record dives times 148 153 seconds Knowing approximate aircraft terminal velocity altitude can determined table shows calcu lations dive Pfeil P731 assuming its terminal velocity 291 mph cluding combined effects constant gravity increasing drag starting speed 47 mph normal level flight speed fifteen seconds after start dive model has descended 3733 feet traveling 250 mph calcu lated time speed good agree ment measured values record project undertaken organization Innsbruck Austria known Arbeitsgemeinschaft Model segelfiug Entwicklung working group model sailplane development Its techni cal leader Fridolin Fritz its pilot Werner Sitar evidently several other members group difficult brief article convey great care took aspects flight proj ect full story requires 78 pages dossier have seen other dos siers demonstrates magnitude effort approaching expended Austrians sailplane speed record Theirs thoroughly professional job doubt its authenticity can sailplane fly faster powered model Because has less drag prop engine pipe limit speed attainable powered dive ap pendages actually use power produce near end long dive Gravity supplied about 25 horsepower Austrian model bottom its dive Can record beaten think can major effort aspect flight must optimized will require expert dedicated group flying model high altitude sur face loading near maximum allowable FAI rules2457 oz/sq ft fliers mountain states get started 10 Model Aviation Pfeil Arrow displayed Brand Electronic Microprop Nurnberg Show picture taken Ron Moulton background photo showing large team supported Austrian record-breaking effortthe mountainous terrain looms behind them
Edition: Model Aviation - 1978/08
Page Numbers: 8, 9, 10
6 THE Ki th* watch 1 recuir CU IDe S thumb rw sec n 1 tal t thro weqi estirr oiIii Ix Ii- 182 IN oz 3 LBS craft oss sec lOT CC corrections terminal velocity model claimed least 2742 mph suspect slightly higher addition timing system used 1976 primary system used 1977 fully automatic photocells detect passage airplane same kind equipment used inter national racing events 40-foot-wide bank photocells located end 50-meter measured course bank consisted eight Heuer HL 2-21 di rectional photocells pointed upward Ad jacent photocells spaced less wing span apart plane flew over narrow-beam photocells triggered two banks photocells connected Heuer HL 305 timing computer printed elapsed time 1/1000 second elaborate system provided superb accuracy solving timing problem latest technology expensive requires careful alignment also makes flying demanding since course 40 feet wide wider course permitted FAI would have required photocells orient pilot difficult task flying through narrow corridor yellow ribbon ground extended far beyond measured course flying site 6600 feet above sea level Normal air density altitude 19% lower sea level allowing 9% higher terminal velocity Sitar Fritz used same design 1977 before increased its weight 30% raised terminal velocity 14% also climbed much higher 1976 height determined two meth ods wing span carefully measured frames movie film taken start DIVE PROFILE Drop Speed Speed Increase Feet MPH MPH/sec 047084680210 199883203 3431077194 5151261184 7121433172 9341593160 11791740147 14441874134 1 7281996122 20292106110 2345220599 2675229388 3017237178 3370244069 3733250161 4103255453 compared other frames known distances along ground measurements showed altitudes test flights 1800 feet over 4000 feet second method used indicate height time dives stopwatch record dives times 148 153 seconds Knowing approximate aircraft terminal velocity altitude can determined table shows calcu lations dive Pfeil P731 assuming its terminal velocity 291 mph cluding combined effects constant gravity increasing drag starting speed 47 mph normal level flight speed fifteen seconds after start dive model has descended 3733 feet traveling 250 mph calcu lated time speed good agree ment measured values record project undertaken organization Innsbruck Austria known Arbeitsgemeinschaft Model segelfiug Entwicklung working group model sailplane development Its techni cal leader Fridolin Fritz its pilot Werner Sitar evidently several other members group difficult brief article convey great care took aspects flight proj ect full story requires 78 pages dossier have seen other dos siers demonstrates magnitude effort approaching expended Austrians sailplane speed record Theirs thoroughly professional job doubt its authenticity can sailplane fly faster powered model Because has less drag prop engine pipe limit speed attainable powered dive ap pendages actually use power produce near end long dive Gravity supplied about 25 horsepower Austrian model bottom its dive Can record beaten think can major effort aspect flight must optimized will require expert dedicated group flying model high altitude sur face loading near maximum allowable FAI rules2457 oz/sq ft fliers mountain states get started 10 Model Aviation Pfeil Arrow displayed Brand Electronic Microprop Nurnberg Show picture taken Ron Moulton background photo showing large team supported Austrian record-breaking effortthe mountainous terrain looms behind them