January, 2003 - RC Soaring Digest

“A Vintage Sailplane is any gliderout of production since 1958, or a morerecently built glider with appearance,performance and construction characteristics similar or comparable togliders manufactured before 1958.“A Classic Sailplane is a glider thatis at least 25 years old, but is notcategorized as a Vintage Sailplane.The Vintage Sailplane Association1709 Baron CourtDaytona Beach, FL 32124Classic Division“Classic sailplanes are defined asgliders more than 25 years old. Thisdistinguishes them from VintageSailplanes, defined as any glider out ofproduction since 1958, or a morerecently built glider with appearance,performance and construction characteristics similar or comparable togliders manufactured before 1958.“The Classic Sailplane Division,chaired by Jim Kellett, addresses theneeds of the older (but not Vintage)sailplane owner, pilot, or enthusiast.“Owners or enthusiasts of ClassicSailplanes are encouraged to initiateand manage websites for their type.Webspace is available free of chargefor such sites through the generosity ofa donor - if you’re interested, contactAl at asw22pilot@bigwings.org. (Thesites hosted on his server can be seenat http://www.classicglider.info.)“There are several interesting challenges to the owners and pilots ofClassic Sailplanes. Many in this fleetare the earliest examples of the majorshift in the design, construction, andmaterials of sailplanes toward FRPconstruction (vice wood, metal tube,fabric, and metal monocoque). However, there are far fewer repairman inthe general aviation communityqualified to work on FRP materials, atleast compared to those skilled inworking with earlier materials. Inaddition, many manufacturers arehard pressed to provide technicalsupport to this aging fleet, especiallywith the actual numbers of a specificmake and model are relatively small.One of the most important contributions of the Classic Division is thepromotion of “self-help” informationwithin the community of owners andpilots.Page 4“Therefore the Classic Division encourages the development and maintenance, by volunteers, of websitesdevoted to specific machines whichqualify as Classic. (See the links toknown sites at the bottom of thispage.)“Type Sites” for Classic, near-Classic,and Vintage Sailplanes:Briegleb BG-12/16BG-12BDusterFauvel Flying WingsIlindenka (The only Macedonian Sailplane)Libelle (Is this one inactive?)Libelle (Carl Neidermeyer’s Page)Rolladen-Schneider (The “LS” Gliders)Schreder SailplanesSchweizer SGS 1-20Schweizer SGS 1-26Schweizer SGS 1-35Schempp-Hirth Austria SHKSchempp-Hirth Mini-NimbusSchempp-Hirth CirrusSchempp-Hirth Standard CirrusSchleicher ASW-19Schleicher ASW-24CALENDAR of EVENTSand classic ships. SSA observers willbe available all week. The week willend with the Sailplane HomebuildersAssociation’s Western Workshopwhere there is much more fun to behad. Make your plans now to attend.Contact:Jeff Byard13555 El Camino RealAtascadero, CA 93422805-461-0488; jbyard@thegrid.netSeventh Annual Midwest Vintage/Classic Sailplane Regatta June 7-15, 2003“Sponsored by: Vintage SailplaneAssociation, Wabash Valley SoaringAssociation and Mid-America AirCenter Located at (38 46' N 87 36' W)near Lawrenceville, Illinois.“Come join the fun, show off yourvintage/classic glider. limited hangarspace available, first come! Bring yourship and fly with us. 2000 ft. tows 25.00. Buy one month membership for 100.00 and check out and fly in ourSchleichers for club rates. 2000 ft. tows 15.00, Glider Rent 10.00/hr.“Cookouts many evenings or meals atlocal restaurants or pubs. Nearbymotels and camping (or camp on thefield).“They have a Cessna that can towContacts:slow, a winch and three grass runwaysBud Brown (618) 943-2076in addition to the paved one. SomeRR 4, Box 51,interesting stuff for sale, too. A goodLawrenceville, IL 62439restaurant a few steps from the stagingorarea. Camping allowed, Motel list to beDave Schuur (618) 584-3328published later. Mark you calendar.16705 E 300d’ AveThis should be a good one. KutztownFlat Rock, IL 62427is located NE of Reading PA adjacentdschuur@frtci.netto Hwy 222, and close to Interstate 78.“Tell us you’re coming & what gliderVSA National Rally - August 23rd you’re bringing! If you don’t have ato September 1, 2003ship, just come and have fun.”The 2003 Eastern VSA Regattawill be held at the Kutztown PAAirport May 23 - 26 2003.“The Vintage Sailplane Association isplanning to hold its first ever VSANational Rally from August 23rd toSeptember 1, 2003 at the MountainValley Airport in Tehachapi CA. Therewill be lots of vintage and classicsailplanes flying and on display. Otheractivities include various tours of areaattractions, nightly BBQs, variousspeakers and an El Mirage Dry Lakeexpedition. There will be both Aeroand Auto tows available as well as ourfamous western soaring conditions.This will be a great opportunity topursue some of your Silver, Gold andDiamond Badge legs in your vintageHappy Flying!Judy SlatesZikaGSO ONEARIN’R/C Soaring Digest

Winter Time ProjectsAby Paul CoxSoarCrashnburn@aol.comFairdale, Kentuckyhh, winter is here! Now’s the timefor me to dive back into that notquite finished super project plane, theconstruction of which has beenplagued by the mysterious disappearance of packages needed to completemy project. Sometimes, I wonder if thepackages were routed through theBermuda Triangle or simply took aslow ship trek around the world.My current 2 year project is an ACMEproducts AGF-9000. It has some stateof the art components and was likelydesigned entirely by a mad scientistwho had way too much time on hishands!which wasn’t in their catalog thismonth. Does anybody out there knowthe item number for about 3 grams ofdehydrated holy water ballast? (Justkidding, guys.)end up having a big party that night,and then I have really bad headachesfor days.All joking aside, before I head back tothe workbench I wanted to remindeveryone to be careful with their histarts. This cool weather can makethem brittle, and they can snap.I did get a special handmade batterypack for this plane a couple years ago,a state of the art NiCad pack, whichreminds me, I guess I better look intoordering a different charger thingee for Which reminds me; keep your carrunning in case you have to make athat battery.quick exit from the flying field. DeadThis project has been delayed so many batteries won’t allow for a quickgetaway should the residents of thetimes that I sometimes forget about it;it seems that every time I mix the resin Bermuda Triangle come after yourplane stuff! nand the hardener together, we alwaysOnce I have obtained the unique list ofcomponents, combined with the skillof my craftsmanship, and 3 tons ofblind luck, I will be able to out-soaranybody on the planet, maybe evenGordy. (I once thought Gordy was ableto see thermals, but I now realize thathe always travels in the direction of theoncoming fronts. This, of course,explains how he knows where all thethermals are; he’s been through themall before.)It hasn’t been so easy obtaining all ofthe parts for this plane. The servoscame from the actuators of a solarcollector that could have been on aretired Japanese satellite, the 100thread count coconut spar wrappingsfrom Guam are probably surfingaround in the Bermuda Triangle, andthe pull-pull system which is madeentirely of knitted spider web collections is a work in progress. (Mygrandma was working on this, untilthat nasty spider bite took her from us,rest her soul. My other grandma hastaken over for her, and so far, has beendoing a pretty good job.)The wing ribs are still at my ex-wife’shouse. She threatened to actuallythrow them away last year, until Ireminded her that I made them fromher great-grandmother’s cypressrocker, and that they were the onlykeepsake she had left.I also have to send a letter to theVatican. I am trying to find somethingJanuary 2003Page 5

The Myth of the Bell-shaped Lift Curvenot been physically exact.”2 Hecontinued, “One has to emphasise thatwith tailless aircraft it is more difficults many already know, a Hortento find the necessary compromiseIV sailplane has been restored and between good performance, desirableis now displayed at theand safe flight characteristics, easyOberschleissheim division of thehandling on the ground and cheapDeutsch Museum, just outside Munich. construction costs, compared toAlthough this surviving example‘normal’ aircraft.”might be capable of flying it will notdo so, being preserved as a museumReflexed profiles andexhibit.centres of pressureABy Martin SimonsStepney, AustraliaHowever, Professor Berndt Ewald,formerly of Darmstadt TechnicalUniversity, is hoping to get a newHorten IV tailless sailplane built (fullscale) and flown. Whether he will beable to find time and financial supportremains to be seen but it would bemost exciting to see one of thesefamous sailplanes in the air again afterso long. It would also give us a chanceto answer some outstanding questions.I wrote most of what follows in thefirst place for the InternationalVintage Glider News magazine, inwhich future developments ofBerndt’s project will doubtlessappear from time to time. With afew appropriate changes, it may beof interest to model fliers too.Contrary to some claims, the Hortensdid not make any astonishing discoveries. For example, they have beencredited with being the first to realisethe benefits of the so-called reflexedwing profile. This is wrong. Windtunnel tests on reflexed wing sectionshad been performed before 1924 andthe results widely published.Alexander Lippisch used them for the‘Storch’ series of tailless aircraft. Therewere many examples available todesigners before the Hortens begantheir work. In the old-fashionedterminology, reflexed profiles have acentre of pressure which does notmove appreciably at the changingangles of attack normally used inflight.3 Unlike the ordinary camberedtype of profile, they do not try alwaysto push the nose down. (The nosedown pitching tendency of the usualtype of wing is normally resisted by atailplane or a canard forewing.)If there is no tail a reflexed wingprofile which does not require thenose-up balancing force is an advantage for balance and trim but to usethem is to sacrifice some performance.In terms of lift and drag, reflexedprofiles are relatively inefficient.FlutterThere were other difficulties which theHortens never solved. One was wingflutter. Karl Nickel wrote, “I haveexperienced flutter with the taillesssailplanes Horten H IV. Beginning atapproximately 140 km/h (87 mph) itstarted to rattle and shake and to flapThe Horten brothers, Walter andReimar, from 1934 produced theirseries of tailless sailplanes andpowered aircraft. Great things wereclaimed and much was expected.What the Hortens did, for whichthey deserve much credit, was

Page 2 R/C Soaring Digest ABOUT RCSD R/C Soaring Digest (RCSD) is a reader-written monthly publication for the R/C sailplane enthusiast and has been published since January, 1984. It is dedicated to sharing technical and educational information. All material contributed must be exclusive and