mmc205
Senior Heliman
Location: Pottstown,PA - USA
| You state below that the bearings are "strong enough" as the specs below illustrate.
In the world of engineering, which you must not belong too, there are certain parameters that have to be looked at that de-rate these numbers such as mounting specs (extra clearence, radial movement in th bearing mount), shock loadings, L10 life, lubrication, etc... Essentially, a bearing that is truly rated for the below loads for 10x10^6 cycles (which is 58 flights at 17,000 rpm) will last a lot less long if any of the items mentioned above are working against it. Bearings in car wheels for example last a lot longer even though the L10 life is longer mostly because their usually perfectly lubricated, loaded relatively lightly and thier only doing about 600 rpm at highway speed. This probably why even some of the high quality aftermarket bearings fail relatively quickly. This is not to say that running a heli richer and easy would absolutely not kill a bearing. If the manufacturing tolerances of both the bearing and the holder stack against eachother, it probably won't last long, nor will it if the internal races of the bearing arn't close to the nominal spec. When you buy really good bearings, even small ones, you can pay hundreds or even thousands of dollars each for ground races and balls selected from inventory to meet the particular bearing race perfectly.
Dynamic Load,,(Kgf) 441 (pounds 972)
Basic Load,,,,,,,(Kgf) 231 (pounds 509)
Heli's don't fly, they beat the air into submission!! |
