Rotor tach setup and tappet breathers

[Dellis]

I have 29 foot AK's and after imputing the 1666 number , the reading is 32 km (I take this as 320RPM best I can get to is 340 turning tight)Is this right for this size blades?If not where does the magnet need to be mounted on the prerotator disk to make the 1666 right?Also, apart from small filters to go on the tappet cover breather for a subaru,where can the hoses be run to stop the bit of oil misting around the gear box and prop?Dave

[NiqueNaque]

Dave,The 1666 number converts straight to RPM, regardless of the magnet radius. My tacho (Liam brand) displays it as 32.x where the decimal is the single digit revs. You'll find it is not important as a tacho is only useful when winding the blades up past 120 RPM - watching the string will deliver more joy.I have a set of Jack Allen wide chord blades - 23'10" diameter, they run at 330 - 340 normally, so yours sound about right.You only need to vary it if you want to work out speed for different bike rims - on a bike.You could duct the oil breathers into the carb inlet (after the filter) to remove the misting, this is how it is on a car, it may help with upper cylinder lube. However, you should check your plugs for fouling more often if you do.Cheers,Nick.

[telf]

We were doing 330-340 in Paul's Raf2k/hybrid.telf

[asra]

Hi Telf,Did you get my emails? I'm waiting on paperwork from you please.LlewellaThe law of Inverse Relevance: the less you intend to do about something, the more you have to keep talking about it.

[asra]

Llewella an email on its way to you from me.Mark

[asra]

Dellis, you will get all sorts of opinions about the desirability or otherwise of variuos gauges. IMEEHO it is important that they don't become so much the centre of attention that basic flying is neglected. Their value lies in their ability to give you what may be crucial information at a glance, thus avoiding the need to concentrate on one parameter and so neglect others.Obviously you should learn to judge what your rotor is doing, but having a gauge to correlate with what you are seeing and hearing can help this learning process.John EvansThink logically and do things well, think laterally and do things better.

[Tim]

The rotor tacho is a good guage when used correctly. Unfortunately most low hour pilots use it to find out the minimum Rotor rpm's that they can give the gyro full throttle on take-off. This is a bad practice that is habit forming and will ultimately get you into trouble. The rotor tacho should be used as an information guide only, and not for prescriptive determination.Tim McClure

[Brian]

Another point to consider is that where one type or size of rotors may rev at a particular rev, another set could rev, at diferent stages of operation, at an entirely diferent rev but do the gyro may well perform the same.Instruments are great things but attention needs to be in seeing and being able to feel whats happening . My personal opinion is that the simpler your first gyro is, then the more you will learn, quicker !! Nothing like learning hand starting of the motor and rotors !!You never know how far you can go, till you get there !