929freak
07-17-2008, 11:39 PM
putting a new bell and clutch on my .37 hawk pro(had my first "hot start"). noticed the bearings felt just a touch notchy,so I am gonna p/u some new bearings.My question is do I run the bearings as they come,or open them and put in some high temp synthetic grease,or run them dry(not really an option to me,but heard of people doing it!!)?
I am planning on buying the best ones available at my lhs,probably just some sealed "greens",I wish they had ceramics!(too impatient to order,and wait)....thanks for the info and,or feedback....!
GyroAl
07-18-2008, 12:07 AM
Your bearings may be rough now, simply because some of the powder from the burned lining has worked its way into them. Try soaking them in a paint thinner or something similar. Then spin them a few times and see if they smooth out.
In any case, one of the best things I like about the clutch sustem like that used on the Hawk (same as seen over the years in a number of high end German helis) is that these bearings that support the clutch bell, only have to spin while you are starting the engine and while the engine is idling (all low load and rev situations). As soon as you get the engine reving, and the clutch engages the bell, they no longer spin, as now the complete system, clutch, clutch bell and fan all turn as one unit.
This is why I know of some that have well over 800 flights and are still using the same bearings. There are even some 60 designs with this system that use oilite bushings here just because of their low load and speed application.
The bearings that support the clutch bell on most other designs, spin at the rpm of the motor while in flight (17,000/rpm for 10 minutes or so each flight!!!) and are a lot smaller, so they are considered a regular maintenance item....not so on your Hawk or the Raven 50, as they both use this system. :thumbup: