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Part# 10-01021


An inaccurate tachometer can waste performance, fuel and engine life. Mechanical tachometers are notoriously inaccurate and should be checked at each annual and 100 hour inspection or any time aircraft performance is in question. The TruTach II Optical Digital Tachometer measures the true speed of your propeller from inside or outside the aircraft. Just point it at the propeller or rotor blades and TruTach II will directly display the rotational speed with a resolution of 1 RPM. No connection to aircraft systems is required and measurements may be made at any speed setting from 240 to 70000 RPM.

Direct display is available for 2, 3, 4, and 5 blade propellers. Digital Signall Processing assures rock-solid display in single and multi-engine aircraft as well as helicopters. The compact 4-inch instrument weighs just 4 ounces and may be used with fast turning ultra-lights and kit plane propellers. Just turn it on, select the number of propeller blades and point. Automatic shut-off turns the unit off if you forget. The Tru Tach II includes a standard 9 volt battery providing 150 hours of operation.


It is working well!

May 11, 2021

It works just as advertised, was priced right, delivered very quickly so whats not to like!

Carl K
April 10, 2021

Works great. Easy to set up and use. As others have said, in certain low light conditions it doesn’t read a value but in daylight, works like a charm.

Kent F
March 1, 2021

awesome. great way to verify RPMs on a glass cockpit engine monitor

Royce R
February 1, 2021

Works well, cant wait to try it out on all of my airplanes to see how far off the mechanical tachs are.

Jim P
December 29, 2020

Works very well. A good cross check of my tachometer.

Bill P
December 6, 2020

Works perfectly, as advertised. Shall, light, simple to calibrate, and easy to read.

October 17, 2020

Mounted it on the top of my Piper 140s dash with a piece of velcro. Works great, far more accurate than the old mechanical tach and gives me a sort of heads up display. Only two negatives (not really a fault of the unit). When the setting sun is from behind, the reflection off the windshield can cause it to read double the RPM. When the ambient light drops below a certain threshold (just after sunset) it can no longer read the RPM.

Christopher O
October 6, 2020

Works perfect.! Also it is easy to check calibration. Just point it at a fluorescent light bulb 3600 rpms!

Johnny W
September 17, 2020

Installed with velcro in less than 5 minutes. Works well.

Eugene S
May 26, 2020


Q: What are the panel dimensions for the TruTach II?

The dimensions are 2-1/4" W x 1-7/16 H x 3-3/4" D. This product in not meant to be installed in a panel.

Q: Does the Trutach II Optical Digital Tachometer come with a protective casing or box?

The Trutach II Optical Digital Tachometer is packaged inside of a box.

Q: Do you have to set the Trutach II Optical Digital Tachometer for 2, 3 or4 blades every time you turn it on in a two blade C-172?

No, the Trutach II will store the desired number of blades and start with this input every time.

Q: Does the Trutach II digital instrument remain on for the duration of flight, or is one constantly cycling it prior to altering engine parameters?

The Trutach II is able to monitor changes in RPM and display them in real time. There is no need to turn the instrument off during flight.

Q: Does the TRUTACH II OPTICAL DIGITAL TACHOMETER Part # 10-01021 come calibrated or have the capibilities of being calibrated?

Per Trutach: The only calibration available is to switch from 2-5 prop blades.

Q: Will it work if I put it on the glare shield inside the aircraft?

Yes, the Trutach II is intended to be put on the glare shield for prop reading.

Q: Is this Trutach II Optical Digital indicator an FAA/EASA approved item and ifit cannot be installed in the panel, can it be used as primary engine instrument?

This unit is not FAA / EASA approved since it is not intended to be installed in a panel. You will still need to keep an approved panel mount tachometer.

Q: Does this unit come with a Certificate of Conformity stating that it complies with some form of National Calibration Standard or aa certificate of calibration?

No certifications are available for part # 10-01021.

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