Era

Lambie Hang Loose

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In 1972 a guy named Jack Lambie wrote an article for Soaring magazine and published a set of plans on “how to build your own Chanute-style hang glider”. He called his design “Hang Loose” (hey it was the 70’s 😉

Experience:
When I saw that article, I knew instantly I had to build one. I can remember sketching ideas for such craft since I was in 5th grade. So I ordered the plans Carleton and I built one. On one of the days of testing we happened to get photographed and interviewed by the local newspaper. (I think the reporter was just happening by at the time)

We had to make some changes to the design: for one thing we could not get bamboo to make the ribs. Instead I cut them out of 1/8″ plywood, about 1″ thick top to bottom and mounted the ends between two pine blocks. Heavier than the bamboo but a better fit to the shape for sure.

We also could not get the yellow pine that was suggested and used spruce I think, but it had some very small knots in it that did cause a problem at one point. (Spar failure in flight!)

At the time, I already had a sailplane pilot’s license (you can solo at 14 and it was cheaper than flying power planes) and of course I had flown a lot of model airplanes, so I was elected the test pilot. You can see me in that photo with my leg out to move the CG (centre of gravity) forward a bit.

The angle of the tail was not set properly so I could not get the angle of attack enough and basically just fell down with the thing. After fixing that back at Carleton’s house (right across from the field in the picture) it worked great. We both flew it many times down a little 20′ grassy drop-off.

The feeling of the glider lifting you up as it gained speed was AWESOME.

You could not really turn the thing at all…too much stability in roll. We talked about adding some tip-dragger rudders or ailerons but the flight times were short enough you didn’t really need any left – right steering.

We had a few snafus but by never flying higher than it was safe to fall we didn’t get hurt. Spectators would offer to hook us up to their cars with a rope and and tow us …but we were too smart for that 😉

Lambert The Major Lambert / R-266

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The Lambert R-266 features a solid master connecting rod and two piece crankshaft. A two piece magnesium alloy crankcase, split on the cylinder centreline, is held together with ten bolts. The front section carries the front main ball-bearing and thrust ball-bearing. The inlet passage and valve lifter guides are cast in the rear section.

Cylinder barrels are nickel semi-steel castings. Removable cylinder hads of aluminium alloy with exhaust and inlet ports toward the rear, are held in place with four long studs which run through the crankcase. Enclosed valve actuating mechanism is at the rear of the cylinders.

Accessories and their drives are grouped at the rear making for easy cowling.

Equipment incules a propeller hub, exhaust ring, carburettor air heater and muffler, tool kit, and instruction and parts book.

Type: 5 cylinder air cooled, fixed radial
Dept of Commerce Rating: 90 hp at 2375 rpm
Displacement: 266 cu.in
Compression ratio: 5.55-1
Bore: 4 1/4 in
Stroke: 3 3/4 in
Length: 30 3/8 in
Diameter: 33 in
Weight: 214 lb
Fuel consumption: not more than .55 lb/hp/hr
Oil consumption: not more than .025 lb/hp/hr
Lubrication: Pressure and dry sump
Ignition: Dual Scintilla
Carburation: Stromberg NAR 3
Spark plugs: 2 per cylinder Champion

Lambach HL.II / Delft Student Aeroclub Lambach HL.II

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As next project, Lambach designed a small single-seat biplane intended for aerobatics. It was the intention that at aerobatic contests held in the Netherlands it could beat the German competition. For construction of this new plane, designated as HL-2, Lambach founded the Lambach Aviation works. It was housed in the ‘Starlift’ elevator factory at Voorburg near The Hague. The HL-2 was flown for the first time from Ypenburg airfield on 4 May 1937 by Hein Schmidt-Krans, carrying the civil registration PH-APZ. The plane showed to have excellent flying characteristics, but because there was little time to practice for the next aerobatic contest held at Eelde airfield it scored a 3rd place only with German pilots on 1st and 2nd place. Pilot on the HL-2 during this event was again Schmidt-Crans.

After this contest it was handed over to the national aviation school NLS for training of future aerobatic pilots. However, during the 1938 aerobatic contest the Germans won again very convincingly! Pilot of the HL-2 on this occasion was Dick Asjes who finished at the 7th and last place. Because of the worsening international situation no contest was held in 1939. During the five-days war in May 1940 the HL-2 was destroyed at Ypenburg by German bombs. Although Hugo Lambach designed as the HL-3 an attractive high-wing twin-engine passenger plane the Lambach factory was soon closed and Hugo Lambach joined the Fokker aircraft works. He died in July 1972.

Replica: Delft Student Aeroclub Lambach HL.II Replica

Lambach HL.I / Delft Student Aeroclub Lambach HL.I

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When in the early 1930s members of the Delft Student Aeroclub were trying to bring down the costs of tuition they decided that in the absence of public finance they would build their own aircraft. J.W.H. (Hugo) Lambach, a former DSA member, was asked to design a machine which would be cheap to produce and operate. A group of about twenty-five students set about its construction; some members of Pander Aircraft, including their chief designer Theo Lock, also assisted from time to time. Work began in the spring of 1934 and the Lambach HL.I made its first flight on 5 July 1935, piloted by Dick Asjes.

The HL.I was a cantilever low wing monoplane with wings of constant chord and rounded tips. Its tail was conventional, with a braced, straight tapered horizontal tail mounted on top of the fuselage and a largely rounded vertical tail with a rudder which extended below the tailplane, moving within an elevator cut-out.

Its fuselage was round in section and tapered a little both forward and aft of the wings. The front open cockpit was just ahead of the wing leading edge and the rear one, from which the HL.I was flown solo and which had a short, faired headrest, was at about two-thirds chord. During early testing the HL.1 was configured as a single seater; it was also initially powered by a 34 kW (45 hp) Szekely SR-3 three cylinder radial engine installed with its cylinder heads exposed for air cooling, but this proved unreliable and was replaced by a 67 kW (90 hp) Pobjoy Niagara seven cylinder radial, also with cylinders exposed. Both engines drove two blade propellers. The HL.1 had a fixed, conventional undercarriage with its mainwheels on tall, vertical, largely faired legs braced laterally by an inverted V pair of struts and longitudinally by trailing struts; there was also a tailskid.
Operational history

The HL.I was appropriately registered as PH-DSA on 1 January 1936. In March the DSA transferred it to the Nationale Luchtvaartschool (National Flying School) at Ypenburg Airport where it served until the Germans invaded the Netherlands on 10 May 1940. The HL.1 avoided destruction by bombing which took many Dutch aircraft that day. The aircraft began to degrade after being moved out of its hangar by German forces and it was eventually handed back to the Technical University of Delft for instructional purposes, where it was dismantled.

Engine: 1 × Pobjoy Niagara, 67 kW (90 hp)
Propeller: 2-bladed
Wingspan: 11.20 m (36 ft 9 in)
Length: 7.70 m (25 ft 3 in)
Gross weight: 585 kg (1,290 lb)
Maximum speed: 140 km/h (87 mph; 76 kn)
Seats: Two

Laister-Kauffmann Yankee Doodle 2 / TG-4A

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Yankee Doodle

With the need for military trainers on the outbreak of World War II, Laister designed the two-place Yankee Doodle 2 from the original LK-10A / Lawrence Tech Sailplane with straight wings and automatic control hook-ups. Under the sponsorship of John Kauffmann, a St. Louis businessman, simplified versions were produced in quantity as TG-4A’s for the USAAC in 1942-43.

Laister-Kauffmann XCG-10A Trojan Horse

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The XCG-10 is a large military glider capable of accommodating 30 troops or a freight load of 5 short tons. It is a high-wing cantilever monoplane with a deep forward fuselage tapering to a tadpole boom which supports the tail unit. At the break in the bottom lines of the fuselage clam-shell doors give access to the main hold 30 ft.(9.15m) long, 7 ft. (2.14m) wide and 8 ft. 6 in. (2.59m) high, which can accommodate a 155mm howitzer or a 2 1/2 ton truck. Structure is entirely of wood with plywood covering. The wings are fitted with Fowler-type landing flaps and have an overall span of 105 ft. (32m).

The XCG-10 and XCG-10A were two different craft. The 10A was 42 place. Although some sources say the 10 did not exist and the project was changed to 10A in design stage, the 10 was built both as a static test article and a flight test article. The internal hold size was slightly larger for the 10A to accommodate the GM 6X6 truck. The wingspan stayed the same.

Laister-Kauffman XCG-10 / XCG-10A
Crew: 2
Armament: none

Laister-Kauffmann LK-10A / Lawrence Tech Sailplane / TG-4

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LK-10A

In 1938 Jack Laister completed a gull-wing sailplane, which was referred to as the Lawrence Tech Sailplane after its sponsor. Repainted red, white and blue and renamed the ‘Yankee Doodle’ it competed in a 1939 aerobatic competition at the Paris airshow.

Yankee Doodle

With the need for military trainers on the outbreak of World War II, Laister designed the two-place Yankee Doodle 2 from the original that utilized some of the features and technology from the LT-IV but transitioned to a dual cockpit and straight wing arrangement.

Lawrence Tech

A flat-top Version with increased performance also has an ATC. A ‘bunnynose’ LK, flown by Harold Hutchinson, held the national multiplace goal record of 399 km/ 248 miles from 1956 to 1967.

The Vintage Sailplane Association has copies of the military manuals, color scheme drawings and paint chips available.

One LK-10A belongs to the National Soaring Museum.

LT IV
Laister-Kauffman TG-4A

LT IV
Wing Span: 14.173 m
Wing Area: 12.5 sq m
Structure Weight: 124.7 kg
Flying Weight: 214.3 kg
Wing Loading: 17.14 kg/sq m
Root Chord: 137.2 cm
Tip Chord: 50.8 cm
Aspect Ratio: 16
Fuselage Length: 5.867 m
Stabilizer Span: 269.2 cm

LK-10A
Wing span: 15.2m /50ft
Wing area: 13.33sq.m / 165sq.ft
Empty Weight: 215kg / 475lb
Payload: 181kg / 400lb
Gross Weight: 396kg / 875lb
Wing Load: 29.7kg/sq.m / 5.27lb/sq.ft
L/DMax: 22 89 kph / 45 kt / 55 mph
MinSink: 0.98 m/s / 3.2 fps / 1.90 kt
Aspect ratio: 15.1
Airfoil: NACA 4418, 4409
Seats: 2
No. Built: 156

Lawrence Tech IV

Laister LP-46 / LP-49

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The LP-49, popularly known as the ‘Forty Niner’, is a Standard Class single-seater that was first rolled out in prototype form, designated LP-46, on 4 July 1966. It is of metal and glassfibre construction, but designed to be sold in kit form for the amateur constructor, and more than 50 LP-49 kits had been sold by early 1976, about 35 of which had been completed and flown.

The high cantilever wings are of laminar flow section, the extruded aluminium main spar booms being curved in a chordwise direction to follow the aerofoil section; the roll contoured aluminium sheet wing skin is butt jointed and flush riveted with blind pop rivets. The semimonocoque fuselage is made up of two premoulded glassfibre halves joined over aluminium bulkheads and fittings. The tail unit is of aluminium with a swept back fin and rudder, and the landing gear consists of a shock- strutted retractable monowheel with a brake and a glassfibre nose skid with a steel shoe; a fixed shrouded tailwheel replaces the retractable tailwheel of early production aircraft. The LP-49 has an automatic aileron and dive-brake control hookup and internal control- surface counterweights.

LP-49

The ship is approved for spins, loops and wing-over, and has been static tested to 12 g. The LP-49 was sold in both kit form and as a complete, ready-to-fly sailplane.

Jerry Haynes
haynesja@yahoo.com
Need help to find Stabilizer ? Elevator / pictures / drawings to build a new tail group

28 May 2018

LP-46
Span: 13.56 m. / 44.5 ft.

LP-49
Span: 15.0 m / 49 ft 2.5 in
Length: 20 ft 7.25 in
Wing area: 13.29 sq.m / 143 sq ft
Aspect ratio: 16.9
Airfoil: NACA 64(3)-618
Empty Weight: 215 kg / 475 lb
Gross Weight: 408 kg / 900 lb
Payload: 125 kg /275 lb
Water ballast: None
Max wing loading 30.72 kg/sq.m / 6.29 lb/sq ft
Max speed: 135 mph /117 kt / 217 km/h
Stalling speed: 30 kt / 56 km/h
Max rough air speed: 117 kt / 217 km/h
Min sinking speed: 0.63 m/sec / 2.07 ft/sec at 50 mph / 43 kt / 80 km/h
Best glide ratio: 36.5:1 at 58 mph / 50 kt / 92.5 km/h
No. of Seats: 1
No. Built: 53

LP-49