DC-3 and DC-4 Fabric Elevators etc...
I'm a former DC-3 and DC-4 captain for Millardair in Toronto and I saw this question about fabric control services and thought I'd help you out.
The elevators were heavy and lacked hydraulic assist thereby making control inputs heavy. In the DC-4 as an example, the fabric elevator combined
with a counter weight spring aided the pilot in pulling back on the yoke.