Before we can explain something about the DC-2, we need to start with the DC-1, so let's have a look.
The DC-1 was of all metal construction with a streamlined fuselage sitting on top of exceptionally strong monocoque construction cantilevered wings. The 710 hp Wright SRG-1820-F3 engines were enclosed in streamlined NACA (the forerunner of NASA) designed nacelles that not only reduced drag but also helped with engine cooling. Hydraulically operated main gear was located in the engine nacelles and retracted to about half the diameter of the wheels.

This was mainly for safety reasons, as the partially exposed wheels would help cushion the impact of a wheels-up landing. Variable pitch Hamilton Standard propellers and split trailing edge flaps assisted with takeoff and landing, the flaps also acting as a form of speed brake helping reduce the landing speed to 58 mph. A great deal of attention had been made to passenger comfort, a detail often overlooked in previous airliners. Comfortable reclining seating mounted on anti-vibration rubber pads was provided for 12 passengers as well as a kitchen and a practical washroom/toilet.

Because the cabin floor was fitted to the top of the wing centre section there was no structural member intruding into the cabin, allowing more freedom of movement inside the aircraft. Extensive soundproofing led to interior noise levels that were considerably lower than any other airliner of the time. A thermostatically controlled steam boiler mounted on the engine exhaust kept the interior temperature at a comfortable 21° centigrade with the cabin air being changed every 60 seconds. In addition, self-adjustable fresh air vents were installed next to each seat. Of course, all these creature comforts would be of little consequence if the DC-1 were not structurally sound, a problem that plagued some previous airliners. Because of the lack of any sophisticated stress testing facilities and limited knowledge in all metal aircraft design, Douglas designers chose to use materials that were far stronger than necessary in many aspects of construction. The end result being that the DC-1 was not only very safe, but also extremely strong.

At exactly 12:36 pm on July 1, 1933 the DC-1's wheels left the ground for the first time, marking the beginning of the end for the wood, fabric and wire airliner era. Further flight-testing followed, including the all-important single engine test (which was successful), before the DC-1 was delivered to TWA on September 13, 1933. It was not long before TWA realised that the DC-1 showed great promise and offered a chance to recapture the commercial airline market, so they promptly placed an order for 20 DC-1s. The airline also requested that the aircraft incorporate several improvements that they felt were necessary. To meet TWA's requirements, Douglas decided that rather than trying to modify the existing design, it would be better to come up with a new aircraft based on the DC-1. Consequently, on May 11, 1934, the DC-2 made its first flight and was delivered to TWA 3 days later. To the casual observer, the DC-2 looked very similar to the DC-1. However, due to the availability of more powerful 855 hp Wright SRG-1820-FS2 engines, the fuselage had been lengthened by 2 feet allowing for an extra 2 passengers to be carried. The lengthening of the fuselage also altered the aircraft's centre of gravity so the position of the wings was moved rearward to compensate. Like its predecessor, the DC-2 set new levels of passenger comfort and service, including the introduction (by TWA) of the first "in-flight" movies. When compared to all other contemporary aircraft, the DC-2 was the safest, most comfortable and fastest airliner in the sky (see cross-section). It went on to establish 19 United States speed and distance records in its first 6 months of operation before receiving the Collier trophy for "outstanding achievements in flight" in 1935.

Such was the success of the DC-2 that many airlines both in the United States and abroad rushed to place orders for the aircraft. In addition to the flood of orders for the DC-2, manufacturing rights were sold to Fokker in Holland and Nakajima Hikoki KK in Japan. A single DC-2 ended up in Russia where the design was copied, slightly altered and put into production (without a licence) as the ANT-35. A KLM Royal Dutch Airlines DC-2 (PH-AJU) was to achieve worldwide fame when, in October 1934, it was entered in the London to Melbourne air race. It followed KLM's regular 9,000-mile commercial route which was 1,000 miles longer than the official race route, made every scheduled passenger stop en-route (even turning back once to pick up a stranded passenger) and finished second, only 34 minutes flying time behind the winning custom built de Havilland "Comet" racing plane.

Famous KLM DC2 Uiver PH-AJU.
From the period 1934 till the second World War, KLM had 18 DC-2's in service. Since it's too much to explain everything about the KLM DC-2's, we will focus on the famous PH-AJU Uiver. The DC-2 was a twin star engine airplane which could offer place to 14 passengers. It was produced starting in 1934 at Long Beach California USA by Douglas Aircraft Corporation (Douglas Commercial). Douglas delivered as already written above on July 1st 1933, the DC-1 which was quickly followed by the DC-2 and let's not forget the world famous Dakota DC-3. For sure the best selling aircraft in the world. This was mainly the result of the 2nd World War. The DC-1 prototype had a beautiful tapered wing, a retractable gear but just 690 HP engines (see cross-section). Due to the fact that Parmentier had seen this model in America he could convince Plesman about this "aircraft of the future". At the time KLM decided to buy this Douglas model, the DC-1 was already replaced by the DC-2.

In total no more then 156 DC-2's where built and before you knew it, they where already replaced by the flying legend!
Just some details from the first KLM Royal Dutch Airlines DC-2 PH-AJU.