ORIGINAL: Antique
A needle braring on the big end of the rod is necessary because most fliers don't want to use enough oil in the fuel...Large converted 2 strokes can get by on 10%, smaller ones need the same amount as a small glow engine...Then there will be complaints about oil on the fuselage, just like glow engine...Can't have it both ways.....
If the needle bearing was not necessary Tom at BME would not go to the trouble of pushing the crank pin out and replacing it with a harder one....
Like Saito small gas engines ? The FG36 (36cc) does not have needle bearings on the con-rod.
Like oldies spark plug small engines ?
On a 4 Stroke engine the amount of fuel (with oil) is smaller than a 2S engine and oil-fuel flow mix does not goes directly to crankcase (and con-rod) as 2S does.
Lubricity of gas(petrol) is much more than methanol.
I've count the needles on a small needle bearing availables today (caged), and the contact surface with the crankshaft pin is so small and can cause more troubles than a plain bushing.
Only my experience.
Best regards