Here are a couple of examples of what I mean by difficult... This is from an interview with a russian pilot.
http://airforce.users.ru/lend-lease/english/articles/golodnikov/part1.htmn.g.
Later it was revealed that the Englishman was a certain Major Rook and that he spoke excellent Russian. He had completed our Kachinsk Aviation School. But he spoke English during the entire training period and Russian only at the farewell banquet. At the banquet he said, “I could not [speak Russian] because I am an offical and it was forbidden.” One of our squadron commanders, Kovalenko, studied with him at aviation school. No matter how much Kovalenko tried to coax him:” Hey, why are you evading, you understand everything”, but still failed to convince him to speak [Russian].
This Rook fellow flew the I-16 one time, and climbed out drenched in sweat. “Let the Russians fly this airplane!”
Altogether we spent about five days in the transition training. We learned the general layout: “There is the engine, here is where we top off the fuel tank, there the oil” and so on. We did not go particularly deep into the airplane’s design. We talked, we sat in the cockpit, we taxied a couple of times, and then flew the airplane. I made three flights, that’s all, and I was transitioned. Like they told us, “You want to live—take a seat.” Safonov flew first. He sat in the cockpit four hours familiarizing himself with the layout and then flew the airplane. The rest of us followed him.
A. S. Was there any kind of special selection for transition?
N. G. No. We were trained by squadron.
A. S. Nikolay Gerasimovich, what was your first impression of the Hurricane?
N. G. My first impression was “Hunchback!” Such a “hunchback” cannot be a good fighter. Subsequently my first impression did not change. I was particularly alarmed by the wings. They were so thick. The wings on the Hurricane were thicker than on the Pe-2.
A. S. Was the Hurricane easier to control than the I-16?
N. G. Yes, it was simpler. I did not experience any difficulties in learning the airplane or how to fly it.
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or this is neat too
Let me say something else about the air frame. The Hurricane had a very light tail. We were based on sandy, insufficiently packed airfields. It was mandatory that a technician or mechanic sit on the tail when we were taxiing to keep it on the ground. We even flew with a technician sitting on the tail. We had a technician named Rudenko who flew around in a circle sitting on the tail. He sat with his back forward and was unable to jump off because his hands got caught in the skin of the vertical stabilizer. He sat there until the pilot landed the aircraft. There were cases when men fell off the tail and died.