I appreciate that Shawn, and there were some excellent discussions by yourself and Nick re max range speed with turbines fairly recently somewhere close by.
of course the '47 speed will depend on the state of the blades and whether or not the main power port in the carburettor is opening or not. Just under that setting the max range speed must be the best, just over it and fuel disappears like there was no tomorrow, at about 22.5 inches or maybe a bit more. no two carbies are the same.
The reason I pursue the subject is because of the mass emergence of the R44 onto the airwork scene. Although i have not experimented with them in the same way as I have with '47's i suspect that the numbers would be similar.
I accept that there may be some useful difference between the carburetted and the later fuel injected models with the better blades.
Another useful guide on the pre landing power checks was to see what the margins were between IGE hover and full throttle. Five inches usually meant straight up and 3 to 4 inches would be acceptable for a 'max perf' T/O.
OGE hover power checks of course are simple, provided one is smart enough to remember to do them, many are not. one inch spare for climbing at that same weight and one more if one is to be operating close to trees etc where the airflow will be disturbed. don't forget that the air close to the ground may be quite a bit hotter than where the power check is done, meaning that a bit more will be required.
Another tip is one inch in the six cylinder machine usually represents, 10 hp and 100 pounds of weight that can be picked up, vertically, so calculate the power check according to the load to be dropped or picked up.
very simple really, just never pull more than is there.