Re: Fixed Prop installation.


Bill Kinney
 

A couple of comments on installing a fixed prop (or any prop, actually!).  Be SURE that the prop sits tight on the shaft, and that the key does not hold it off. The best way to do this is to install the prop on the shaft WITHOUT the key, mark how far on the shaft it sits.  Pull it off, and the reinstall with the key in place and make sure that it goes just as far on. It is not unusual that new keys are too high, and the prop bottoms out on them before it is fully engaged with the shaft. If this is the case, file down the key until the prop sits as it should.

A propeller should be driven almost entirely by friction with the shaft, not so much by the key.  Having a good tight fit on the tapered part of the shaft is essential. If the prop is at all loose the key will be damaged, and the prop is at risk of coming off.  Especially when a tabbed over washer is used as the nut lock as is typical on these metric shafts.

There has been a long standing argument between people who know more than I do about greasing the shaft (or not) when installing the prop.  I doubt it really matters much one way or the other, but I do not use grease.

Finally, never, never, never use a hammer in place of a proper puller to remove a prop. If a yard worker does this, fire him on the spot. This is bad enough on a standard shaft drive, but could be deadly on the C-Drive.  The gears, bearings and housing are not made for this kind of shock loading. If a prop is really stuck and the puller is not getting it loose, get a bigger puller.  Failing that, heat the prop (hot!) with a torch, and then tap gently to loosen it while continuing to pull straight back as hard as your tools will allow.

Bill Kinney
SM160, Harmonie
Hollywood, FL, USA

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