I have had a Globee tach for over a year now but hardly use it. It is very difficult to obtain a good reading with it. I have tried into the sun, away from the sun, black props, grey props, wood props etc with the same results. Is it just a bad design and they all are not very reliable or was mine made on friday afternoon before a three day weekend?

I have had many tachs and never had any problems like this. One of the main reasons I bought this one is the fact that it uses cheep 9v batteries in lieu of the smaller watch style ones $$$.
Thanks,
Jeremy

I'm not familiar with that design. Can you post a picture or website or something? Is it that you can't see the readout?
There is a way to test the accuracy using a flourescent light. Let me know_bob

Here it is at Tower:
http://www2.towerhobbies.com/cgi-bin...1&I=LH3731&P=1

It just does not have a very stable reading when used to measure prop RPM. Jumps by +/-200 to +/-4000 RPM, yes 4000.

Calbrates just fine at 3600, solid as could be.

(spelling corrected!!!!!)

That it does, or doesn't have a stable reading?

I dont use mine a lot either but I find it very effective and accurate IF held toward the center of the prop arc. If held out at the tips it jumps all over the place

i also have a globee and it jumps all over the place. i thought it was just me. i might send it back then. i will not pay for junk.

Thats what I was wondering. I don't want to send it back and just get another one that does the same. I looks and feels so nice, too bad it does not work as good as it looks. Any one else out there have any comments on this tach?

I have a Hanger 9 tach. On overcast days it doesn't work well.
The measurement jumps all over the place. With one small prop (a 9x6 on an OS46FX) it refused to provide any reading. I have also had problems in the past when using wooden props (versus APC nylon props).

Today I illuminated the prop with a flash light from behind, then
measured the RPM also from behind. All readings were very steady, even the small 9x6 prop. Actually, the tach has never worked better that it did today with the illuminated prop.

I used a rather large flash light, but I suspect that even a tiny flash light (e.g. the single AA battery type) would be sufficient.

I have read at least one similar account of using a flash light with a tachometer. Search the lists you may find it.


It makes sense... you won't get a strong signal without some reflected light.

Jim thanks for the tips.

I am just dissapointed that with todays modern technology the tachs seem to be worst that ones made 15 - 20 years ago. My friend had an old Heathkit one that worked great and I had an anolog one made by Royal. Both worked flawlessly. I think we both paid less than five bucks at swap meets for them. I remember that after 5-7 years use I sold mine for a lot more that I paid for it. Boy was I stupid!

So are there any tachs out there that work well? (That are still made)

I have the Tower Hobbies special... uses 2 standard AAA batteries, and gives me rock solid readings in a wide variety of lighting conditions. I even used it once a few minutes after sunset (but still light enough to read the LCD). It doesn't do 4 bladed props, but if you have one, just use the 2 blade reading and divide by 2.

And it's only $21.99.

http://www2.towerhobbies.com/cgi-bin...1&I=LXPT31&P=1


"In the event the readings become erratic, change the direction of the model is facing by 90 degrees and take another reading."

The prop should pass between the light source and the tach. It measures the interuptions, not the reflections.

Help.......
Have a tach called "Advanced Digital Tachometer Voltmeter"
Model 602-1.
Operated by pushing a button repeatedly, which cycles the tach thru 2,3,4 blade props then 4.8 and 9.6 V.
2 problems, on first selection, every 'bar' on the display partly lights up and its hard to see the reading. The other problem is it eats 9 V batteries, I thought it may be 'bumping' itself on in the flight box, so now I disconnect the battery when not in use. Any ideas ?
Thank you

Have you tried gluing on a small, raised ring of plastic around the button to protect it from accidentaly being pushed? :idea:
It won't help make the display easier to read though... Perhaps a tinted plastic cover over the display, with a stiff hinge so it swings into a position to cut the glare???

To Strato 911.
Thanks Dennis, your 2 suggestions instantly fixed both problems.
Regards from down under.
G.

I'm always glad to hear my rantings have helped someone... check my sig.

Here I thought it was just me not using my glowbee correctly. I will try just reading from the center of prop if that does'nt work it's history.

I have the Globee. I have found it to be accurate when used in a particular manner. That is, hold it close and at a 90 degree angle to the prop. Close is less than 2 inches. I have found the Globee will pick up on reflections (flashes of light) from other shiny surfaces such as bright aluminum engine parts, and shiny cowl finishes. This confuses the photo sensor and alters the reading. Getting close to the prop blades eliminates this interference. Get the prop as much as possible directly between the tach and the light source. Inspect the alignment of the optical sensor with the hole in the end of the tach. It should be centered, and parallel with the plane of the surface of the hole. If needed, separate the case halves and align the sensor. Keep the battery fresh. Just because the display lights up does not mean the electronics have enough power to work accurately.

These types of tachometers are cheap because they use cheap photo sensors. They need close to ideal conditions to work properly.

If you want a very accurate Tach for less than ideal conditions, look at the TNC Tachometer. At least go to this site and read the technical write-up about Tachometers.
http://www.ulster.net/~tnc/tncweb.html

I have the TNC PT10S. It is about $100. But it is very accurate, stable, and will read from over 12 inches at dusk on an overcast day. It will register in conditions my Globee will not.

I have one of the GloBee tachs also. I haven't used it much, but so far I'm satisfied with it's performance. I have noticed, though, that it gets better readings near the prop hub than at the tips, as others have testified to as well.

I figured that this was because the blade has a wider chord near the hub which makes a much larger "shadow" than the narrower chord near the tip.

Also, I've only used it on APC props so far, I don't think I've used it on any Master Airscrews yet. Maybe the black color of the MAS props will make it work better out at the edge of the prop disc.

The weather forecast here is looking like it might be quite conducive to flying activities this weekend, so I'll have to try it on on some different props.

Like I said, though, I'm satisified so far with the unit's performance. Good stable readings, just have to hold it nearer the hub than the tips on the prop disc. So far, that hasn't been a major problem, just an idiosyncrasy to work around.

My Globee tach works fine. Daz...

The TNC is the best tach I have ever used, with 1 small problem..I always forget to turn the switch off, and the 9V battery runs down..Solution ?? I replaced the slide off and on switch with a small pusbutton...Now the battery lasts forever......

For the most part mine works fine. Sometimes in bright sunlight I'll get eradic readings.

THANKS GUYS IVE BEEN LOOKING FOR A CHEAP TACH HOW ARE THE ACE UNITS .I HAVE SEEN A COUPLE.THANKS FOR ALL THE INFO

If you already have the GloBee tach, here's a suggestion that came from one of the forums and helped me:

Pull off the housing for the lens and paint the inside of it flat black, then reinstall. It helps keep out extraneous light. I used a black permanent marker.

Definitely kept me from giving mine to someone I don't like.

GoMike

Bump
Very interesting thread.

Wow... Lazarus returns, LOL!!

I didn't know the place was still alive.
I joined RCU when it converted from RCO way back in the day.
I was a moderator here at one time, then the place seemed to get taken over by advertisements and new management.
Crazy...