Hi. The engine too cold. You should close the radiator during the landing, and push some throttle to keep the engine warm. There is a thermometer of cylinders, but is shows 0, because you must select one cylinder (there is a switch*, left and right 0-7 number. No matter the number, just pick one). You have to keep the temperature between 200 and 300 celsius!
The oil temp should keep around 60 celsius.
(This is true with the G.50 too).
*I looking for some BR.20 video on the net, but every self-appointed teachers forget this switch...
