mustangman177

Ordered a Glowbee Intellitech tach from Tower. Upon using it I'm getting outrageous readings. Idle readings are at the 5,000 rpm. half throttle at 24,000 on a OS 46 FX. I knew my OS 46 was good, but not that good !!! What's up with this ? Will Tower take it back and replace with a new tach ? Has anyone else had this problem ?

Thanks

Cary

big max 1935

My Feedback: (9)

Is this the one with the different prop blade settings? 2.3,& 4 blade? Any how point it at a frorescent light & it should read 3600 RPM.It may have wrong setting. Easy check on tachs. Good luck, Max H.

jester_s1

If the fluorescent light test is successful, it may be that the background in front of the prop is too dark. The optical sensor works best against a solid light background.

Gray Beard

My Feedback: (-1)

I have three tachs under my bench, one is a glowbee and one is a small Hobbico. Both pass the light test but will never give you a good reading. That's why they are under the bench. I finally broke down and bought the TNC tach and it works perfect. The problem was spending the $100.00 on it. After I bought it I started testing other peoples tachs against it. I finally hit a upon another tach that worked. It was the H-9 multi tach/volt meter combo. So far I haven't found a bad one. So far I have only found one globee that worked. Just because a tack passes the light test doesn't mean it works, it means it can read a light bulb.

RC_Fanatic

My Feedback: (1)

Under some light conditions, even my TNC gives odd readings. I think it is when sun reflects off the rear of the prop (I check from the rear and the sun is always behind the start-up stands at our field.) However, if I angle the tach down at 30 degrees, the problem goes away.

mustangman177

Sorry I haven't responded quickly.

The Tach passes the light test as prescribed. Will try using at brighter light settings when using on plane.

Use to have a hobbico tach that worked decent. It gave up the ghost recently.

Bax

My Feedback: (11)

If you are trying to take a reading under AC electric lights, you'll always get bad readings. That's because lights using house current flicker at 60 Hz, or 3,600 RPM (as the tach sees it). You must either get a reading in light outside, or use lights powered by direct current. We used to use an automobile headlamp powered by a 12-volt automobile battery when our test cell was indoors quite a few years ago. That gave good readings.

If you are under a tree, then the sunlight filtering through will also cause erratic readings, as the leaves let different amounts of light through. Make sure you have a good contrast between the propeller and the background. A black prop against a dark background will also give bad readings.

If you are too far from the propeller, you'll also get bad readings.

Kmot

My Feedback: (24)

I had a GloBee tach and used it for years. Loved it. I had heard that the TNC tach was the "Cat's Meow" so I decided to order one when I was a little flush with cash and I sold off my GloBee in anticipation of the TNC arriving. After 6 weeks of waiting, and never a single reply to my e-mails to Fromeco asking where is my TNC tach, I finally gave up and cancelled the order. I bought another GloBee and like the first, it works flawlessly.

That said, all the above comments are valid. You must have proper lighting to get an accurate reading. I find the easiest thing to do when taching an engine is from behind the prop, angle the GloBee down slightly.

jester_s1

I learned about this stuff when I was big into shooting (planes displaced that hobby) and bought a chronograph. Lighting is everything with those units. If you think it's hard to get a sensor to pick up a prop then try getting it to see a bullet! The very best lighting for chronographs is a white overcast sky. Second best is a sheet of white poster board reflecting direct sunlight or strong DC electric light (as Bax said). It's not so much the amount of light in front of your prop that makes the tach accurate as it is the color contrast. A clean bright white background makes any prop blade very black by comparison.