New Aircraft Quiz #13

There were several early aircraft designs that extensively used plastic-bonded plywood moldings-construction in their structure.

To be specific-name the TWO designs of twin engine aircraft that were among the first to use this novel construction BUT, and this is a large BUT-only one prototype of each was built and successfully flown by the SAME manufacturer. And, and this is a big AND-no production of either aircraft ever ensued. So, don't think of de Havilland or their Mosquitos.

Name the manufacturer and model designation of each aircraft. Name the different engine by make and model of engines with their horsepower of each aircraft. What year did the FIRST prototype successfully fly?

As usual, all answers required to win this quiz. I have NOT checked with Wikipedia on this to see if they have any clues or answers.

Congratulations Rob,

You are essentially correct so I give you full credit for your quick, but not record reply to these quizzes. Your Juptner reference which I also have shows the Approved Type Certificate designation for an aircraft initially revived by the Langley Aircraft Corporation of Port Washington, NY in 1942 that was never produced.

Let's back up a bit in history by way of full explanation. Langley built two prototypes of a twin engine aircraft using plastic-reinforced molded construction, the first of which was the Model 29-65 with two Franklin AC engines of 65 Hp each. My other reference shows first flight of the 29-65 in 1941, not 1940. The second prototype with more needed power was the Model 29-90 with two Franklin 4AC-199-E4 90 Hp engines after initially trying two 75 Hp engines.

The Andover Kent Aviation Co. of New Brunswick, NJ obtained a production license from Langley Aircraft Corporation, but no production ensued because of the advent of World war II. They improved the design and obtained the Approved Type Certificate #755, granted 12-29-1943; prior aircraft were registered Experimental NX.

Langley Aviation Corp. of New York City then revived the prototype in 1946, re-designating it Model 2-4-90 TWIN FOUR, but no production ensued. (Juptner writes "it is estimated that 3 examples might have been built"). The prototype was still in registration by 1965 as N5170S or N51706. I have not checked these numbers for any registration currency as I write this. Juptner shows the prototype Langley 2-4-90 with NX29099 registration.

The Langley 2-4 TWIN FOUR was a streamlined design four-seat cabin monoplane with wrap-around windscreen and with fully-cowled engines faired into a low wing, twin tail taildragger with streamlined wheel pants on fixed gear. Props were fixed-pitch. The wings were tapered into the fuselage at their roots. Think a shrunk-down Beech 18 for similarity, especially in the rear cabin/tail area on side view. The aircraft could fly with one engine shut down.

Performance:

Max speed: 138 mph

Cruise speed: 117 mph

Initial climb rate: 695 ft/min.

Range; 350 miles

Weights

Empty: 1,738 lbs

Gross: 2,850 lbs

Dimensions:

Wingspan: 35'0"

Length: 20'6"

height: 7'1"

Again, congratulations on your quick response.

Timothy,

Thank you for finding that great color photo of the Langley 2-4-90 Twin Four; Juptner's and other black and white photos just do not do it justice.

There is some irony in the design concept. Martin Jensen designed it to not use materials such as aluminum that were critical to war effort. England was already at war with Germany at the time of it's inception. Jensen's design used Honduras mahogany laminated thin strips bonded with a plastic agent in a mold with heat to form most components of the aircraft using the "Vidal" patented process. Later, when the USA had joined WWII after the Pearl Harbor surprise attack of 7 December 1941-these plastic agents also became war-critical components and could not be made available for civil production aircraft.

The Langley 2-4-90 Twin Four might have been an economical to operate multi-engine production low cost trainer or business aircraft of its day, but such was not to be.

Timothy,

If you enter Duramold Aircraft Construction in the Wikipedia box on this site-it will reveal quite a few aircraft and manufacturers using variations of the process, including the largest example-the Howard Hughes H-4 HERCULES, or "Spruce Goose", except of course there was no spruce wood in that wooden design. Hughes used birch, if memory serves. Henry Kaiser actually had the ambitious idea in 1942 of a large wooden cargo airplane for the war effort, and it was first known as the HK-4, but Kaiser pulled out and Hughes went it alone. Hughes actually flew the H-4 on Nov. 2, 1947 in Long Beach Harbor, for the first and only time.

Sven Swanson in Lincoln, NE area also had some early homebuilt designs in the 1930s that, if just varnished-would look similar to the Langley 2-4-90 Twin-Four construction. He used wood strips in diagonal wrap around a curved frame to sheathe a fuselage with glued wood. Swanson's method was labor intensive and not mass-production ready, but the Brits built a LOT of similar wooden de Havilland Mosquitos. Exigencies of war can produce miracles.

Could Swanson's unique method have sparked the plastic-bonded wood process of the "Vidal" patent?