"Directed Evolution Instruments for Designing Consumate Systems" by Zlotin & Zusman begins with the following statement:
In summer of 1961(?) my elder brother Mikhail found a summer job at Kobuleti Young Pioneers' camp in Georgia on the shore of the Black Sea. They needed a musician for chidren's entertainment and he played well accordion and bayan. My mother did not want him to go alone and we (mom and I) went to Kobuleti too. Mom rented a room in the town while brother lived and worked in the camp. Other rooms in the house were rented by wives of test pilots from a Moscow aviation plant, who also came to Kobuleti for summer vacation. They did not come on a commerical plane but on the plant's DC-3 piloted by their husbands. The plane was used for various deliveries and apparently such "deliveries" were also permissible at the plant.
Mom befriended those women and when summer ended they offered us to fly with them on DC-3 to Moscow. It was a very bumpy ride. The plane was very susceptible to turbulence so that we puked several times during the flight.
Never ever after that I flew on a plane that handled turbulence so poorly. It was not because of the plane's size. In the 1980s I frequently flew on 2 times smaller planes that experienced no turbulence.
How an aircraft handles turbulence depends on its mass, wing loading, flight controls, and other design factors. Apparently DC-3 did not have "outstanding qualities" with respect to these factors. Especially flight controls improved significantly since the 1930s when it was created.
On the positive side, it was very entertaining to observe the villages and towns from the altitude of just 10000 feet. Modern planes fly much higher (30000 feet) and the view is not as impressive as from a low altitude, when much more details are seen. The most mesmerizing moment came when we started the final approach to the plant's airfield located inside Moscow. It appeared that the plane would touch the roofs of the tall buildings. But it safely landed on the plant's runway.