Your favorite tachometer

I have a very plain Hobbico tach. It has a switch for 2/3 blades and nothing else, except it's tough as nails. Inside the shop I turn out most of the lights and use a mini-Mag light to shine through the prop. As for accuracy, it reads 37k under the lights, even incandescent much to my surprise. 37K is 100 RPMs high, but at least it's consistent. A correct reading would be 36K on the 2-blade setting. I never imagined an incandescent lamp with a white hot filament could cool and re-heat 120 times a second and actually be read by a photo cell. With fluorescent lamps the 120 cycle flicker can be seen with the nekkid eye.

Wayne has a tach that shows the peak RPM while also displaying the actual RPM, but I don't know the brand name. I wonder if there is one that would show an average RPM between two button pushes. When I was trying to get a good launch RPM on my OS 46fx the other day, it was crazy all over the place. Maybe because it needs new bearings. They're still in the drawer.
Rusty

Yes, the Turnigy will shut off automatically if left inactive. I don't remember how long it is though. It takes CR2032 button cells, which are dirt cheap on eBay. It also has a peak RPM indicator beside the real time reading that resets when you switch off the tach.

I have the same Turnigy Micro Tach. Yes it does turn off automatically, but I find I can't switch it off manually. It seems to be tough of batteries, but as was mentioned, they're cheap. Problem with changing batteries is that you need to remove 4 screws to dismantle the tach, which are easy to strip out. Also, the lens can easily fall out when dismantled if you're not careful.
I find the swithces are not all that good & I need to have several shots at changing the blade settings, which goes up to 9 for use on ducted fans.
For all the negatives, It's good for the price. Mine is dead accurate if the fluorescent light test is anything to go by. We have 50 cycle power down here so the reading is a steady 3000. I always use it with an LED light behind the prop when indoors.

Rod.

Oldenginerod wrote:I have the same Turnigy Micro Tach.  Yes it does turn off automatically, but I find I can't switch it off manually.  It seems to be tough of batteries, but as was mentioned, they're cheap.  Problem with changing batteries is that you need to remove 4 screws to dismantle the tach, which are easy to strip out.  Also, the lens can easily fall out when dismantled if you're not careful.
I find the swithces are not all that good & I need to have several shots at changing the blade settings, which goes up to 9 for use on ducted fans.
For all the negatives, It's good for the price.  Mine is dead accurate if the fluorescent light test is anything to go by.  We have 50 cycle power down here so the reading is a steady 3000.  I always use it with an LED light behind the prop when indoors.

Rod.

That's odd. When depressed, the buttons on mine give a satisfying "click". Pressing the power button will always turn it off. I have used the 9-blade setting to tach my stirling engine. I agree the exchanging the battery is a pain and the screws are cheap, but that's why it's $8 rather than 20. I've thought about swapping them with some socket cap screws but I've only changed the battery twice in the four years I've had it.

The tacho displayed is not unique to Turnigy. I have seen several brands but the underlying plastickery and electrickery is exactly the same.

Mine eats CR2032 batteries but it is accurate and easy to use. I have several tachometers for various purposes but this is the handiest for propeller driven measurements.



The buttons on this have a positive click and my only criticism is the display. It is difficult for me to read in bright light but that is my eyesight!

I have both the Globee which I've had for over 10 years and Hanger9 micro tach, both are great tachs and can be both manually turned off as well as having an auto turn off feature the globee reads up to 30k and does up to 4 blades (older tach) while the Hanger9 reads a little higher "I think" and does 9 blades. the Hanger9 tach is IMO not quite as well made as the Globee "feels a bit cheap" and the globee takes a plain jane nine volt battery while the hanger9 takes a button cell however it has a slide out access door and has no screws to remove so it is easily replaced as far as accuracy is concerned both read a steady 3600 via incandescent bulb and I have had no problems with both especially the globee. Anyway here's a pic of them side by side (Bandit)

I have a GloBee IntelliTach. I've had it for several years now.

•10 - 99,990 (32,000 according to the box) rpm operating range readout is highly visible in large 1/2” (13mm), 5-digit LCD display.
•Measures rpm for peak engine performance up to 12” (305mm) from the propeller, and still get readings accurate to the nearest 10 rpm.
•One-button operation to select between 2, 3, and 4-bladed props with prop selection indicator on left side of the display.
•One-year warranty.
Download Manual

Admin wrote:I have a GloBee IntelliTach. I've had it for several years now.

•10 - 99,990 rpm operating range readout is highly visible in large 1/2” (13mm), 5-digit LCD display.
•Measures rpm for peak engine performance up to 12” (305mm) from the propeller, and still get readings accurate to the nearest 10 rpm.
•One-button operation to select between 2, 3, and 4-bladed props with prop selection indicator on left side of the display.
•One-year warranty.
Download Manual

The Globee does read that high? I've had mine so long I don't remember. I though it's max was 30k "Shrugs" (Bandit)

TDbandit wrote:

Admin wrote:I have a GloBee IntelliTach. I've had it for several years now.

•10 - 99,990 rpm operating range readout is highly visible in large 1/2” (13mm), 5-digit LCD display.

It Globee does read that high? I've had mine so long I don't remember. I though it's max was 30k "Shrugs" (Bandit)

That's what their site says, http://www.towerhobbies.com/products/greatplanes/gpmp2500.html I didn't know the exact specs so I just looked them up. Now that you question it   , it does sound a little on the high side. I ran downstairs and dug out the box for my GloBee and the box reads 32,000 RPM max. It must be a typo on their site . I've had it up to the 25K-26K range when checking an old red/gold Tee Dee .010 a friend has.

"Nods" The highest that I've had mine up to was a little over 28k testing a highly modded RB .21 buggy engine on my Hurdy break-in stand turning a fan unit. That for some excitement. And speaking of the TD.010 that is one engine that i've never had. I'm gonna try and nab one up when the Southeastern Model Show comes back around in march. (Bandit)

I downloaded an accoustic tacho on my mobile phone

https://play.google.com/store/apps/details?id=com.javiery.rpmgauge

It was 1/2A NUT who introduced that option. This is what he said in another thread about it:

"Readings have been monitored watching photo cell tachs and amazing enough this thing is spot on within 20rpm
It can be set for RC use
2 or 4 cyl
low rpm pre set and high rpm narrows its -\+ losses"

Lieven

I am using a Hobbico and the Google acoustic mobile phone app both and find the readings pretty close to each other. The latter allows you to tach the engine with both hands free (the mobile phone placed to no further away than, say, 6 feet from the engine so that you can read it), or more importantly, during flight if you shoot a video with a key-chain camera mounted on your plane then check the rpm while you play the video.

I remember that thread and i have a tach app on my phone as well, i went to YouTube found a 049 engine being tach'd and using my phone "tach", had about the same RPM reading as the tach in the video!