Re: Tach problems

[Mi Vida Loca]

There is a simple way to check your tach at no cost other than a little fuel. The way to do it is to find a mercury vapor light you can park close to. With the light shining from behind you after dark run your engine up starting at 600 RPM and see where you are able to "stop the prop". You should be able to "stop the prop" every 300 RPM increase. Continue to do this as high as you can on a static run up.

The next method is to fly behind another aircraft who has a tach known to be accurate. Line up so that you are looking through your prop into the prop arc of the other AC. Adjust the power until you can sync the props. Both these methods is the same principal used in the old days to check the speed of a turn table (stroboscopic effect). Both methods work and will be close enough for your purpose.

The best thing to do is invest in a manifold pressure gauge. The single best method of monitoring your engine's power output. I almost never even look at my tach any more. It's not really the RPM's that you need to worry about, it's the amount of power you are producing. These engines are capable of far more RPM's than we ever will turn them. It's one thing to turn up to red line at SL and another issue at 5,000 feet.

Have a good one




Dave
41 Charlie
Dave's Ercoupe Page
www.flash.net/~dmprosvc/dave
ICQ # 1388138
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