Yankee Doodle was born in college, financed bya stockbroker and bought by the U.S. Army.

CF Z8W

GNw•5yAET5Ey

Soon after World War II, war-surplusgliders dominated the market.

This L-K lOA (its military designation

was TG-4A) has multi-framecanopy panels and stepped windshields.

LAISTER­KAUFFf1AN L-K 10

This is the same aircraft shown above. It has been modifkd with a bubble canopy,cleaned-up nose and wing roots and a takeoff dolly instead of the landing wheel.

For a decade after World War II, compe­tition soaring in the United States waspretty well dominated by a single de­sign-the war-surplus Laister-KauffmanL-K lOA. Although other surplus traininggliders went mostly by their ex-militarydesignations, the Laister design, whichhad the military designation TG-4A, wasuniversally known as the "L-K." It was atwo-seater, but had evolved from a high­performance single-seater.

In the years immediately preceding thewar, the U.S. soaring movement was in adifficult "chicken versus the egg" situa­tion. The growth of the movement washampered by a lack of suitable gliders, andthere was no significant glider industry

BY PETER M. BOWERS

because there were so few customers. Afew factory-built models were in use, butthere were also quite a few that were es­sentially homebuilts. Some were outrightamateur efforts in both design and con­struction, but there also were a few that

had been developed by highly qualifieddesigners and built in suitable shops out­side of the recognized industry. A notableexample of the latter is the single-seat"Yankee Doodle" developed by a school.the Lawrence Institute of Technology (LIT)at Highland Park, Michigan, near Detroit.

In 1933, Jack Laister enrolled in the

aeronautical engineering course at LIT. He

was already a flying enthusiast and haddesigned, built and flown gliders of hisown design while still in high school. Hebrought one to LIT with him and lost notime in forming a student glider club, us­ing his glider. After obtaining faculty sup­port for gliding, he had the students builda two-place glider of his design in theschool shops.

Laister was well along on the design of anew high-performance single-seater whenGeorge Lawrence, president of LIT, sug­gested to him that the school ought tohave another glider project under way.When Laister showed him the drawings ofhis new design, Lawrence arranged for theschool to complete the design details andbuild the glider. Laister then went to workon the project practically full time. Thenew ship, officially designated LawrenceTech IV but nicknamed Yankee Doodle,was completed in June 1938.

The design was thoroughly conven­tional for the time, with a two-piece, full­cantilever wing attached to tubular wingroots that extended from the welded steel­tube fuselage structure in what could becalled a high mid-wing position. Thestraight-tapered wing used a single,wooden box spar, with plywood aroundthe leading edge for torsional stiffness.The steel-tube fuselage was a preferredAmerican practice; most European glidersstill used wood. Another American detail

was the use of a single landing wheelnested in the fuselage when European de­signers still preferred skids.

Unlike many contemporary Americandesigns, which were primarily open-cock­pit trainers, the Yankee Doodle had aneatly streamlined nose and a clean curved

PHOTOGRAPHY FROM THE COllECTION OF THE AUTHOR AOPA PilOT • 81

.,. /7continued

The most notable feature on

the 1938 single-seat Lawrence Tech IV

is its graceful gull wing.

This L-K was modifU,d greatly with separate bubbles for each cockpit, an extended rear fuselage, an enlarged vertical tail a/ld a retractable main wheel.

canopy. But the most notable detail of theLIT glider, when viewed from almost anyangle, was the graceful gull wing.

Why a gull wing? There are severalvalid reasons to justify the added structuralcomplexity: wing tips farther above theground for rough-terrain landings; bettervisibility through certain angles; more sta­bility in circling flight; and, the real rea­sons, aesthetics.

Wolf Hirth-one of the leading Germanglider manufacturers of the 1930s and pro­ducer of a very popular high-performancegull-wing sailplane, the "Minimoa"-wasat a technical meeting when the point wasmade that gull wings did nothing to im­prove the sailplane's performance. After­ward, someone asked him why he usedthe gull wing, since he obviously knewthis before he designed the Minimoa.

Hirth replied, "True, the gull wingdidn't improve the performance any; but itsure sold a lot of Minimoas!"

The Yankee Doodle was an excellent

sailplane for its time and should have beena logical candidate for production. How­ever, LIT had no facilities or staff for suchwork, so only one was made.

By early 1941, the U.s. Army and Navyhad become very impressed by the success­ful use of troop-carrying gliders by theGermans, and hurriedly set up a U.s. mili­tary glider program. This had to be startedfrom scratch-not only did big cargo glid­ers have to be developed, but so did train­ing gliders and the schools in which theywould be used. The existing glider move­ment, the industry and just about anyone

82 • AUGUST 1982

with glider experience were interviewedby the Army. Although Laister, who wasworking for Curtiss-Wright in. St. Louis,was not then in the established glider in­dustry, he was invited to Wright Field topresent details on his past designs. His oldtwo-seaters were unsuited for militarytraining, but the single-seat Yankee Doo­dle had good potential and easily could bestretched to accommodate two.

As a result of his interview, Laister wasinvited to submit a proposal for the designand manufacture of a two-seater. To han­

dle the manufacturing, he joined with St.Louis stockbroker John Kauffman to formthe Laister-Kauffman Aircraft Corporationand establish a small plant in St. Louis.The bid was accepted, and the new firmreceived an order for three flying proto­types of a trainer designated XTG-4, plusone static test article, in October 1941.

The first XTG-4, which was known inthe factory as the L-K 10, was delivered toWright Field in February 1942. This wassimply' a stretched Yankee Doodle. It had alonger fuselage, four feet more wingspanand an elongated military-type canopyover both cockpits. The major structuralchange was to eliminate the gull wing inthe interest of simplified manufacture.

The Army ordered 150 TG-4As, whichthe company called L-K lOA. These weredelivered with trailers, as were similartraining gliders from other manufacturers.

In its stock two-seat configuration, theL-K was a good trainer but had somesneaky tricks. In addition to being verylight on the pitch controls, the mid-wing

configuration sometimes caused it to spin"over the top" from a skid, particularly ifit was flying a little tail-heavy. The fuse­lage would blank out some airflow overthe root of the inside wing during a skid,and over the craft would go.

Another characteristic that made the L-K

tricky as a trainer, particularly on pave­ment, was the location of the center ofgravity (CG) relative to the wheel. On theother military and most civil trainers,loaded CG was ahead of the wheel and the

glider rested on the nose skid and thewheel. This provided automatic drag, orbraking, to smooth out rough automobileor winch-tow starts. The L-K required fastwork with the hand brake during suchstarts. The forward location of the wheel

sometimes led to mild ground loops whenlanding on pavement with a spring-leaftailskid or a full-swivel tailwheel.

The sailplane trainers, based on prewartechnology and soaring procedure, soonproved unsuitable to the military and weredeclared surplus. The Army decided togive its student glider pilots primary train­ing in light airplanes and then familiar­ized them with actual glider operations inde-engined lightplanes such as the Taylor­craft TG-6 (see "Yesterday's Wings: TheTaylorcraft Tandems," July Pilot, p. 73). Butthis program change did not put Laister­Kauffman out of business; the firm built.750 Waco CG-4A cargo gliders and devel-­oped a large, wooden cargo glider of itsown, the XCG-IO Trojan Horse.

Military work was cut way back after thewar, and the firm tried to get into the civil

"-

..

market with a civil L-K lOB model, theYankee Doodle II. It also bought the rightsto the prewar Bowlus "Baby Albatross"one-place sailplane. Such efforts failed,however, because several hundred of the

surplus military training sailplanes, in­cluding Laister-Kauffman's own TG-4A/L-K lOAs, came on the market at a fraction

of the cost of factory-new gliders. This wasa switch on the chicken-versus-the-eggsituation. Although there were now morecustomers for gliders, they did not have tobuy new from the factory; so the industrywas still stymied.

As a result, the war-surplus models dom­inated the soaring scene for more than adecade. Quite a few are still in service astrainers and acknowledged antiques, thenow-booming soaring movement havingits own Vintage Sailplane Association fordesigns more than 30 years old (3103 Tu­dor Road, Waldorf, Maryland 20601).

Although the surplus models wiped outLaister-Kauffman's anticipated civil mar­ket, the firm did help the movement. Thecompany published a service bulletin toinform owners of the modifications re­

quired by the Civil Aeronautics Adminis­tration that qualified the TG-4A/L-K lOAfor a standard licence under Glider Ap­proved Type Certificate G-15, which wasissued June 8,1945.

Being the most numerous of the surplusmodels, as well as having better all-aroundperformance and versatility, the TG-4Apretty well dominated the movement and

the early postwar contests. The L-Ksearned further distinction as the result of

an extensive modification progfam. Thisstarted at Mississippi State University in1948 as an aerodynamic research program,not an attempt to improve the L-K per se.Three L-Ks were converted to single-seat­ers, with recording equipment in the rearcockpits. The most visible change was tothe upper fuselage superstructure. In aprocedure called flat-topping, the structurewas removed down to the top longerons,the nose contours were lowered and

smoothed and a close-fitting bubble can­opy was provided for the pilot in place ofthe former high-drag military windshieldand canopy assembly.

This major change was accompanied byless noticeable changes that did as much ormore to extend the 23:1 glide ratio. Thisincluded careful aerodynamic smoothingof the wing, extending the leading edgeplywood well aft on the upper surface,sealing the myriad gaps in the original de­sign, removing excrescences and cleaningup drag-producing intersections. The aero­dynamics balance areas of the elevator andrudder were removed.

The benefits of the changes, which didnot compromise the structure or aerody­namics of the basic design, encouraged theUniversity of Illinois Glider Club to obtainFAA approval for them. A supplementaltype certificate was granted in June 1958,at which time the L-K 10 design was 16'years old. The Laister-Kauffman firm was

still extant, though inactive, and made theapproved modifications available throughanother service bulletin.

This triggered a great variety of "home­brew" modifications within the specifica­tions by private owners. Not all went thefull flat-top route; many opted for onlypartial modification. Some retained bothseats, using either separate bubbles foreach cockpit or a single, long, low canopy.There also were partial flat-tops and thesimplest of all modifications, the "bunnynose," which merely replaced the militarywindshield and forward canopy with acan toured windshield like that of the 1939Yankee Doodle.

Other owner/pilots performed more ex­treme modifications that called for experi­mental licenses, including lengthening thefuselage to cut down on pitch sensitivity,extending or clipping the wings, installingretractable landing gear and even buildingengines into the nose to provide self­launching capability. One amateur fittedL-K wings to a homebuilt fuselage andwon sixth place in the 1952 U.s. NationalChampionship and second place in 1955.

Since the L-K is no longer competitive,and a point or two in glide ratio is notimportant, some modified L-Ks are nowbeing restored to their TG-4A configura­tion, 1942 Army coloring and all. 0

Intrigued by airplanes long before his first ridein a Travel Air at age 10, Peter Bowers, AOPA

544QS, has since logged more thml 4,200 hours.

LAISTER-KAUFFMANL-K IDA

Specifications

115 mph(military)

140 mph (civil)Auto winch tow speed 63 mphLanding speed 40 mphGlide ratio 23:1Minimum sink rate 3 fps

Simplest of all the clean-lip

modifications on theLaister-Kallffmalls was the

bunny nose, which replaced themilitary's stepped windshield

with extended molded plexiglass.WingspanLengthWing areaWing loadingEmpty weightGross weight

PerformanceNever-exceed speed

50 ft21 ft 3 in166 sq ft

5.27 lb/sq ft475lb875lb

Still mlOther canopy variati<m,

this Laister-Kauffman glider shows

a jIot-top modification. Thelong, one-piece canopy over both

cockpits did not change the

fuselage below the upper 10ngerO/ls.

AOPA PILOT • 83