https://www.youtube.com/watch?v=vDs_P-Oz4GYhttps://www.youtube.com/watch?v=5MwOhNlmUYI2-piper, you start them with a flat belt. We would use a flat belt on the farm to run a couple old machines. I watched a 20-40 and a 30-60 being started about 15 years ago up in Canada. You might enjoy these two videos of them starting one and then gang plowing with five of them pulling 60 plus plows. With that Stan could knock off for lunch having plowed for the week. Of course he would need about 15 sons to help him.
A bit off topic but I have been spending some time recently on the 400 acre estate of the Massey family of Massey-Ferguson. Main house, 9 different free standing homes for the staff, generating dam, lit & paved runway with hanger, stables etc etc etc. Built in the 1920's. Current owner is a polo fanatic. Anyway, there clearly was good money to be made in the farm machinery business in the first half of the last century.