Exo - you are clearly cleverer than me! I have checked the Robinson maintenance manual on line and it agrees that it is a right lateral trim.
I was told the previous info about it being the other way 20 years ago by a CAA examiner and I haven't flown the R22 since.
So, AnFI is correct about the direction of the force but not about its reason - I had forgotten how strange the phase lag and hinges are on the robbie - could it be the mysterious 'wee-waa' that Lu Zuckerman always banged on about?
So AnFI, I apologise for being rude but you are still wrong about inflow roll - I shouldn't have used the R22 as an example as my memories of it are clearly muddied and flawed - however, I am completely correct in which way the aircraft wants to roll due to the phenomenon.