The Airplane - Jay Spenser [55]
If instead you’re watching from forward of the wing, you’ll notice that extension of the leading-edge devices happens relatively late. By then, the jet is on a stabilized final approach to the runway. With all this going on, the wing looks dramatically different at touchdown. That doesn’t last, though, because the crew retracts the flaps while taxiing to the terminal.
You may also notice a bit of flap being used on takeoff. The first increment of flap deployment increases the wing’s lift without significantly increasing its drag, which helps the jet take off sooner.
Others had experimented with flaps, but the Douglas DC-1 marked the first time in history that an airplane was designed that needed flaps. Showing that the time was right, another design taking shape in Connecticut also employed a higher wing loading for increased performance. This was the four-engine Sikorsky S-42, Pan Am’s first oceangoing flying boat, which would make its first flight in 1934. To keep its takeoff and landing speeds within reason, Sikorsky had given it a large plain flap that spanned almost the full length of its pylon-mounted wing.
For their new-technology airliner, Douglas engineers selected a split flap. They put flaps not just on the wings but also on the airplane’s flat underbelly between the wings. And what a wing it was.
The heart of the DC-1 and its successors was Jack Northrop’s multicellular wing, which he developed for his Alpha mail plane. Building further on the ideas of Germany’s Adolf Rohrbach, this remarkable design locked together spanwise metal spars, stiffening members, and the enveloping skin to compartmentalize the wing internally into a series of mutually reinforcing boxes or cells. The result was enormous strength.
The Douglas DC-2 debuted in U.S. service with TWA in 1934. That same year, Dutch carrier KLM inaugurated European DC-2 services, putting European designs to shame. Few people imagined there could be anything better than the DC-2.
Then right away, almost by accident, the Douglas DC-3 came into being.
Trains were the paradigm for domestic air travel before World War II. In an era of slow airplanes, it was only natural for airlines to plan railroad-style sleeper services of their own. As darkness fell, passengers could then convert their seats into beds or retire into fold-down berths and doze off to the reassuring drone of engines.
With this in mind, American Airways (today American Airlines) and Eastern Air Transport each ordered Curtiss T-32 Condor II airliners for overnight sleeper services. America’s last biplane passenger transport, the Condor II combined a fat fuselage with sturdy wings braced by struts and wires.
The Condor II was a product of the Curtiss-Wright Corporation, then the nation’s largest aviation manufacturer. Having equipped the Condor with retractable wheels and aerodynamic engine cowlings, the company touted it as a “high-speed airplane,” although it was derived from a 1920s bomber and evinced World War I–era technology. One can imagine the dismay at Curtiss-Wright when, a week to the day after the Condor II’s first flight, the Boeing 247 took to the air. Overnight that event transformed Curtiss-Wright’s Condor into a pterodactyl.
Engine cowlings and retractable wheels could not help the Curtiss T-32 Condor, a 1933 airliner rendered instantly obsolete by the Boeing 247.
Museum of Flight, Seattle
Cyrus R. Smith, the young businessman recently named president of American Airways, decided that his airline needed a new-technology replacement for the Condor, which cruised at 105 mph (170 km/h). Boeing’s 247 cruised at 180 mph (290 km/h), but it was too small and narrow for Pullman berths. In any event, the Seattle company’s production lines were all