ORIGINAL: Campgems
Matt, my problem is outside with bright sun. It looks as if it needs more of a light/dark transistion than the Magnum does. Oh well, I have two now
Could just be an issue with a dodgy light dependant resistor in yours... or it could be the prop you use. I generally use mine with MAS props which are black with wide blades, so would offer good contrast. With a lighter coloured blade, or if you're holding near outer edge of a narrow tipped prop it'll be more prone to error.
I'm not saying it always gives a perfect reading - occasionally it'll jump from 13000 to 2500 for a second or so, and the reading always fluctuates a little so there's a bit of "averaging" done. Still, what do you expect for $20 or so?
LuftwaffeOberst
It's also good to have if you down the road want to fly twins, you can sync the engines better. Also with a tach, you can keep tabs on how hard your engine is working. I also have a Radio Shack IR Thermometer to know how hot my engine is in those " In Cowel " setups. But that's a different topic.
That was my main motivation for buying mine - syncing the twin engines on my Dual Ace (maybe I should have said "justification" - after all, he who dies with the most toys wins!
) however I've found out (as I mentioned above) that it's actually more accurate to sync twins by ear! There's a certain harmonic "note" that you only get when two engines are running perfectly at the same RPM - it's easy to discern, and you can hear it fade in and out as the engine revs change slightly.
As for the thermometer, I really need to get one of them. What sort of temps do I need to be worried about with engines?