There are a good number of OS46 FXH's locally that are mostly installed in helis (26 at last count) that have the proper gearing for this size engine, the proper loading (600mm blades), and the proper location of the fuel tank relative to the needle valves.

They all run VERY WELL with NO leaning in the midranges!!

On the other hand, I have played with a few that were in helis with 30 size gearing and/or 30 size loading (530 to 560mm blades) and they ALL suffered from the lean midrange syndrome.

So let's be sure not to blame the engine for something caused by items in a heli that it was not designed to accomodate.

Fortunately for the reputation of the 80 and 90 engines, when they came out, they where being installed into 60 helis by more experienced and knowledgeable modelers who knew the importance of matching gear ratios and loads (longer blades e.g. 680 to 700 or 720 blades) in order to get the proper needle settings at hover and wide open. They were changing these at the time of engine installation. Consequently these engines did not suffer the false "lean in hover" reputation that the 46's developed because so many of them where initially being installed in 30 size helis (e.g. Raptor 30's) by the less experienced and knowledgeable of our bretheren who did not understand these more complex relationships.

Heck even some of the manufacturers didn't seem to understand these relationships either, as they made and marketed 46/50 size helis without addressing these issues. Of course this further caused undue blame to be put on the OS46FXH.

The only manufacturers that seemed to understand these relationships from the outset where Century and TSK, as their 46/50 size helis came with the proper gear ratios and for use with 600mm blades. The others all launched such units initially without properly addressing them. Only later did they discontinue these and launch newer models with proper gearing and loading.