Kite Lines - Vol.3 No. 1 - KiteLife

.withdecorated1978France,had on the Flexifoil development ."We were concerned that we weren'tworking on something that had been discoveredbefore," Andrew began. "Yes, wehad a feeling that somebody must havestumbled on this before. Our natural wayof working is trial and error . Neither of usare readers, so we simply hadn't comeacross an airfoil kite ."In 1975, Ray acquired the Newmanbook Kite Craft. There he saw pictures andread of Jalbert's Parafoils for the first time ."I remember writing and telling you,Wilf," Ray said, "and my initial disappointment."They decided, however, that, apartfrom the inflation aspect, they were ontosomething different . The behavior oftheir kite and the flexing spar which adjustedangle of attack in varying windsseemed novel enough to warrant applyingfor a patent .In the summer of 1976, Brenda suggestedthey go to see an exhibition ofkites at London's Institute of ContemporaryArt . This was the first time the inventorssaw actual Parafoils . They inquiredif anyone would be interested in a newkite idea and were referred to London'sthen-new (three months old) Kite Workshopand its director Eric Gibson . Theywalked over to the shop that afternoon .Gibson tentatively expressed interest inAbove, the first full-size Flexifoil to flysuccessfully, 197'2 : eight-foot wingspan,.Left, Andrew riding herd on a train ofsix Flexifoils in Nags Head, NC, 1978 .red one-inch tapeBelow, Ray flies by the seat of his pantstheir kite and gave them their first spinnakernylon . Shortly after, provisionalpatents were approved . The limited productionkite, christened "Flexifoil," wasshown for the first time publicly on October10, 1976, at the British Kite FlyingAssociation's festival at Old WardenAerodrome-five years after its inceptionat Newcastle .Since then, technical work has continued. Cambridge University's Departmentof Engineering has done wind tunnelstudies of the Flexifoil . Maximum pullachieved in diving is in the range of 100pounds . The production model, in1 .1-ounce rip-stop nylon, weighs 135 .5grams and takes 40 minutes to sew .Andrew is working on a high-performancelow-wind spar. Four-foot span 'foils seemto perform satisfactorily ; three-foot spansin a proportionate configuration have notperformed well . The new generation of10-foot 'foils maneuver slugglishly butgain considerably in pulling power . Theyhave increased both lift-to-drag ratio andcoefficient of lift . A 20-foot span 'foil isin work for the application of pullinglarger seagoing craft .Flying line length of 200 feet workswell for the Flexifoil-and is the legallimit for kiteflying in Great Britain . Theoretically,there is no limit to the numberof 'foils that can be flown in train . Twentynineis currently the maximum knownnumber tried . Flexifoil train kites areseparated by a minimum of two feet ofconnecting line-more in stronger winds .One 'foil flies on 60- to 80-lb . test lines .Four 'foils in train in a moderate windrequire 200-lb . lines . The heavier line requiredadds drag . The technique of controlis very difficult, comparable tospeeding a railroad engine around a curvewith a long line of cars attached . Speed ofthe 'foil has been officially clocked at 95miles per hour . Unofficial reports notespeeds of over 100 miles per hour . Theaverage speed is 60 miles per hour . Accelerationfrom 0-95 is less than threeseconds . In a dive from a 200-foot zenith,the 'foil is at the ground in under threeseconds in a moderate breeze .Andrew wrote to me last spring, recallingthe passing of winter : "I went Flexifoilskiing in the meadow last month . Only Ididn't need skis . Gum sole boots on thesnow were quite slippery enough ."I asked the inventors if they wanted toidentify anyone else important to thedevelopment of the Flexifoil . They hadmentioned in early letters that PeterPowell had a great deal to do with popularizationof the two-line stunting kite .Sid Mills and Mark Cottrell were early enthusiastsand experts at Flexifoil flying,helping to show its potential as a sportkite . Mike Pritchard, an expert in fishingrod technology, made the prototype fiberglassspars and helped solve the productionmodel requirements . Jilly Pelham helpedwork out the pattern and the lay and cutof the fabric for production sewing .In the intervening time from theNewcastle-upon-Tyne polyethylene prototypesto the sleek rip-stop productionmodels, Ray and Andrew have maintaineda steadfast friendship and working partnership. Andrew observed recently, whenI asked him to describe himself and Ray,that Ray had a suit which he wore onoccasion while he, Andrew, hadn't yetfelt the need to own one himself . Ray hasbecome more actively involved in the ongoingFlexifoil company production andbusiness matters . Andrew's main interestremains in research and development . Thecompany hopes to market new productsas well as improvements and new uses forthe Flexifoil .In the exploration of "sailing, freeflight and wind generators," the Flexifoil'sfuture should be most interesting . Its placein kite history is already well assured .