The DC-1 was the predecessor to the famous DC-3
. The DC-1 was built by the Douglas aircraft company as a prototype for TWA
. At the time the US Government
had grounded all Folker
aircraft due to a dry-rot
problem in their wooden wings, resulting in a number of high-profile crashes. Most airlines at the time flew Folker aircraft and it was cheaper to buy new planes than peel back the delicate wooden skin for a visual inspection. This lead to a fierce need for new aircraft. Boeing
had just released their Boeing 247
, but the first two years of production were reserved for United
, Boeing's airline. Frye, the head of TWA, had to look elsewhere.
Frye approached Douglas to build his new aircraft. His specifications were the following:
- 14,200 lb weight
- 12 passenger capacity
- 150 mph cruising speed
- 1,080 mile range
- Three engine design
- Ability to take off fully loaded with any two (of three) engines on any TWA airfield
- Landing speed of 65 kts
Douglas knew that there was an engine on the horizon more powerful than any built so far, so he discarded the tri-motor design for twin Wright Cyclone engines.
The DC-1's biggest potential rival was the Boeing 247, however Douglas's DC-1 had many technological innovations that were years ahead of anything else flying.
The DC-1's wings were unique, up until this point all wings were built around a solid metal beam running the length of the wings right through the middle of the fuselage to maintain wing strength and rigidity. The Boeing 247 used this wing design, resulting in a 1.5 foot raised sill in the middle of the cabin. The DC-1's wings were built in three sections, the middle section supported both engines and ran below the cabin, allowing for a flat floor. the other two sections were the wingtips which were bolted on out-board of the engine nacelles. Douglas built the wings as a series of rigid boxes or honeycombs, eliminating the need for a long metal spar. This facilitated a flat cabin floor an a superior wing strength while reducing weight.
To facilitate the 65 kt. landing speed Douglas installed flaps on the DC-1, a first for an aircraft of its size. To be sure the flaps would not fail in flight, Douglas loaded them with 500 lb. of sandbags each. The flaps held, deforming only one half of an inch.
Critics were skeptical of this new wing design, claiming it would not be strong enough to endure the stresses encountered in flight. Douglas countered this by repeatedly driving a steam roller over a DC-1 wing, bolting it on the aircraft and taking off. It was this wing design that changed aviation history.
The DC-1 was ready for its flight trials. The test pilot from Douglas and the co-pilot from TWA took off in the DC-1 and flew to TWA’s highest airfield (I believe it was in Arizona). There the prototype was loaded with sandbags, 500 lb. more than the maximum take-off weight. The pilots then throttled one engine up to maximum, the other to one-half power and started the take-off run. Just after leaving the ground, the TWA co-pilot shut down one engine, frantic the Douglas pilot jammed open the throttles on the remaining engine; the DC-1 continued to climb up and over the mountains to complete the trip on one engine. The prototype actually landed ahead of a Ford Tri-motor that took off half-an-hour earlier than the DC-1. When asked why he shut off the engine in take off, the TWA co-pilot responded to the Douglas pilot, "It's your job to see the plane can fly, it's my job to make sure it can do what the customer wants. I just wanted to see what the old girl could do."
The DC-1's fate is not a pretty one, TWA wanted two more seats in their production aircraft, resulting in the swept-wing DC-2 and later the famous DC-3. The only DC-1 ever built ended up hauling freight in Spain, where, despite it being known as the only DC-1 ever built, it was scrapped.