Made in the USA
and Sold only
Factory-Direct by:

Cardinal Electronics, Inc.

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to ship the same day
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PROPTACH® Specifications
PROPTACH® measures propeller speed without connection to the aircraft as follows:
  • One RPM Accuracy
  • Operates Up to 35 Feet Away from the Propeller
  • (10000 : 1) Ambient Light Dynamic Range
  • One RPM Display Resolution
  • Compatible with Singles, Twins & Helicopters
  • Nothing is required to be added to the Propeller
  • Display Updates Once per Second
  • Direct Display on 2 & 3 Blade Propellers
  • Display Stabilization Technology

PROPTACH® is Warranted for 10 years.


  • Size: 4.3" × 2.7" × 1.3"
  • Weight: 6 Ounces
  • Focused Optical Gain = 15 to 1
  • Loss of Signal Display Annunciator
  • Low Battery Display Annunciator turns on @ 7 Volts
  • Battery: Ordinary 9 Volt (Life: approx. 100 hr.)
  • Quartz Crystal Time Base Accuracy: 0.025%
  • Self-Calibration using any 60 Hz Light Source
  • Digital Filter Display Stabilization Technology
  • RPM Range: 200 - 4500
  • Two Controls: ON/OFF and 2/3 Blade Selector
  • Auto-Power-Off 2 Minutes after the last Optical Input ( i.e., Propeller Stops)


PROPTACH® is an aircraft test tool that has been manufactured by Cardinal Electronics for the past 27 years. More than 16500 units have been accepted worldwide by aircraft and engine manufacturers, maintenance shops, propeller shops, aircraft research facilities, federal and state agencies and, to the largest extent, individual aircraft owners.

PROPTACH® is designed specifically for the aviation task of acquiring propeller RPM at great distance without adding anything to the propeller. It operates under a wide range of ambient lighting conditions to one rpm accuracy and display resolution. It updates its digital display once per second, and it displays directly for 2 and 3 blade propellers, with excellent stability of reading.

There are many optical industrial tachometers on the market, including adaptations of model aircraft units that sell for much less than PROPTACH®, and others that sell for more, but none were designed to do this stated task as well. It works even at acute angles to the propeller arc, such as when viewed from the cockpit of twin-engined aircraft. It works with propellers of four and five blades, but with these, simple arithmetic is required to obtain the true RPM.

The one RPM accuracy of PROPTACH® may be validated by the customer at any time after purchase by aiming it at any 60 Hz light source or any color television. It will indicate 3600 +/- 1 RPM in the 2 blade mode and 2400 +/- 1RPM in the 3 blade mode using 60 Hz light. It will indicate 1798+/- 1 RPM and 1198 +/- 1 RPM in the same settings using the television screen. The unit will never need calibration or adjustment.

PROPTACH® may be hand-held or placed on top of the instrument panel glare shield. It contains a Digital Display Stabilizer that monitors incoming RPM data for credibility and only allows good data to update the display. What this means is: If the unit detects bad data due to ambient light flashes or from holding the unit unsteadily, it will hold-off the once-per-second update until the data are again detected as good, and then resume the update. During the hold-off a "NO-SIGNAL" annunciator will be displayed along with the last good RPM indication. The net result is a display as steady as the actual RPM.

Proptach-3 is the third generation of evolution of the product.

Our extensive customer feedback indicates that mechanical tachometers are not accurate - typically they indicate off of actual by 50 to 150 RPM. The worst reported was off by 300 RPM. Although most mechanical tachometers deviate to the low side of actual, many also deviate to the high side. Mechanical tachometer errors may also be non-linear, thus only knowing the error at one speed, like 1800 RPM, may not predict the error at another speed, like 2500 RPM.

Cardinal Electronics, Inc.

P.O. Box 70136
Lansing, Michigan  48908
Toll-Free:  800-344-9469
Telephone:  517-321-6618
FAX: 517-321-4988

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