RE: Our biggest problem was that the studs that connected the cylinders to the case would pull out causing the cylinder to depart the formation with great haste.. The other problem was the fracturing if the main connecting rod.
So I assume you are describing wear out failures due to simple mechanical fatigue. (?)
It was a nightmare keeping engines on 'em though... P&W crushed the molds for the engine cases years back.. something 'bout liability Our biggest problem was that the studs that connected the cylinders to the case would pull out causing the cylinder to depart the formation with great haste.. The other problem was the fracturing if the main connecting rod... If you weren't Johnny on the spot feathering it, you'd run out of oil pressure, and be stuck with a windmilling prop... the entire engine would then shake it self to destruction But it was a sweet bird to fly... and I have to say I enjoyed the attention it got no matter where we went
The "Super DC-3S" was a factory retrofit design which Douglas hoped to sell to DC-3 operators, but I believe they only managed to sell about 100 to the Navy as R4D-8. Besides the snazzy vertical tail (baby DC-6 style), square wingtips, etc, it had a 3 foot stretch in the forward fuselage, and was powered by Wright R-1820-80 engines. The Army Signal Corps had three or four that they got from the Navy which they used as electronic labs with SSB radios, etc, back around 1959.
I imagine there are quite a few still making the rounds in out of the way parts of the world, and will be for years to come.
This sounds bad. :)
IIRC, the DC-3 was designed at a time when aluminum was a relatively new material for airplane construction. Without much historical data to base the structual sizing on, it ended up being over-designed. That's why they are still around today, they are basically built like tanks.