I advocated setting the RPM at the upper end of the suggested range given by the Manufacturer did I not?
Sasless.
Yes I think you did, but I advocate setting it as per the MM book, (not just within the range allowed by the POH book) as the MM tells you the correct setting for your given weight at time of test so that at all weights then all one has to do is put the collective on the bottom and the RRPM will settle at the correct setting for that weight. Auto RRPM will vary in direct relationship to your weight.
Picture this, flying along all FD&H in an aircraft and the blessed rotor tacho goes US. Dammit, I'll keep flying until tonite or soon as I can get to maintenance, no sweat, everything fine, all - of - a - sudden, the donk quits.
Well first thing one does I can easily tell you, is look down at the tacho, both needles at nought, one poops oneself, nothing surer. But then I remember words of wisdom from check pilot. Because my machine was set up with the correct auto RRPM at the last maintenance check all I have to do is - put the lever right down - gently establish A/S at correct auto speed - be gentle in turns and I know I don't have to worry about RRPM. Easy see.
But if one has the auto RRPM set too high -with a full load and haven't been checked to listen to, remember and manipulate the blade noise as "in range" then one liable to do all sorts of strange things from run out of RRPM to shed blades from overspeeding, all of which makes for a runny red nose and high excitement - for a short time.
So the deal is, round here set the damn things up properly.
Your validating check should have gone something like this, CP "OK let's do an auto from say 3,000 feet. Enter gently and we will be experimenting with different auto RRPM this time and I want you to focus on RRPM noise levels, you have control."
Auto entered and established, now CP says, "Let's listen closely to the blade sound, can you hear it?" CP who has already put the card over the tachos, gives it a few seconds, then kills the donk. CP, "Now listen intently, let's keep it stable for ten seconds, then bleed off some RRPM to the bottom of the green, remember to maintain your landing spot in range, you have control." Student of course is feeling uneasy and deliberately is loaded up with extra thinking to do, but with different settings, held stable for ten seconds and then reset with the card flashed sideways at those intervals to see RRPM, he student soon learns the "sound" and relaxes somewhat.
A simple exercise thrice repeated and life insurance for life. Student should also be reminded by CP to make mental note to self. "Self, I will always from now on set auto RRPM correct on every machine I check fly from maintenance, as that test was done in a machine the CP especially chose to frighten me as the auto RRPM would easily over speed with lever full down." Student can then pass on words of wisdom and demonstrate to others and so on.
Strange the skill of being able to manipulate auto RRPM by monitoring blade noise is not mentioned in the fabled SFAR 73,- with or without the engine running.
Don't forget if you have a machine with hydraulic collective servo and the hydraulics is engine driven, then the auto RRPM must be set with the hydraulics switch selected off if a check has revealed the lever sits lower with hyd on.
Remember this - High auto RRPM will give high ROD prior to impact.
I have also had the dubious honour of owning a machine cross hired to a training facility once, which had to have spindle bearings changed at great expense to me, simply because the training facility chose to set the auto RRPM high and over sped the M/R often.
cheers tet
aa
If you weren't demonstrating some form of exuberance we would all wonder why you are doing this. Enjoy, listen, try to be as precise as you can, it will come to you don't worry, and take care.
cheers tet.