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Chinook Optical Tachometer G2
Reading rotor head speed without risking yours
Text, photos and video by Tom Hintz
Posted – 9-23-2013
The Chinook Optical Tachometer G2 is an optical tool with a “window” through which you look at the spinning rotor blades. This unit sort of backwards engineer’s motion picture technology that uses lots of images to depict motion. A slotted wheel behind the window spins at tightly controlled speed determined by a built-in micro controller that uses the speed of this disk to show you “frames” regulated by that RPM. When the disk reaches a specific RPM the rotor blades appear to stop when viewed through the “window”. An easy-to-read LCD screen shows the actual RPM of the rotor head.
The Chinook Optical Tachometer G2 reads rotor head speeds from 500 to 3300 RPM (2 blade systems) with an accuracy of +/- 10 RPM! It also has an on-board memory to save RPM readings but there is nothing in the instructions about labeling saved readings for identification later. I consider this to be a non-issue as we use the readings to make changes in our helicopters and once we achieve the wanted RPM, saving those readings is of no value.
The Chinook Optical Tachometer G2 is 117mm-long, 20.5mm-thick, 78mm-wide and weighs just 120 grams. It requires one 9V battery for operation and has a low battery indicator on the LCD screen. A rocker-type switch on the top turns the Chinook Optical Tachometer G2 On and Off. Oddly enough in today’s Pacific Rim based electronics world the Chinook Optical Tachometer G2 is made in Canada!
Whether you use the Chinook Optical Tachometer G2 at the flying field or in the yard, reading rotor head speed has never been safer or more accurate. You really do just look through the window and use the dial to adjust the speed of the Chinook Optical Tachometer G2 until the rotor blades stop. I am not sure just how far away from the helicopter you can be as I have been able to clearly see the blades stop on helos while they were flying by at the field. You certainly do not have to get close to the helicopter for the Chinook Optical Tachometer G2 to work or be accurate.
When you turn the Chinook Optical Tachometer G2 on the slotted wheel inside has to get up to speed which only takes several seconds. The LCD screen will change to show the current Chinook Optical Tachometer G2 RPM setting when the disk has reached operating speed. Then while looking through the window you use the thumbwheel on the front to adjust the speed of the wheel in 10-RPM increments. You can hold the dial in the up or down position and the increase or decrease in wheel speed accelerates.
That really is all there is to it. In every way we can figure to check the accuracy of the Chinook Optical Tachometer G2 it has come out to be spot on. Using the Chinook Optical Tachometer G2 is flat simple and quick.
If the Chinook Optical Tachometer G2 has a fault it is that the On/Off switch is not guarded. I got to the field one day and was going to show the Chinook Optical Tachometer G2 to other pilots but it had turned on in the case somehow and the battery was a goner.
The only other issue I have with the Chinook Optical Tachometer G2 is that the battery compartment is a very close fit. Getting the old battery out to replace it can be a little trying. A small problem to be sure but there just isn’t much wrong with the Chinook Optical Tachometer G2. Both problems are admittedly minor but I had to at least try to balance the praise.
The Chinook Optical Tachometer G2 really is a must-have tool for RC helicopter pilots. It is super accurate and very easy to use - two qualities that make any piece of equipment worth having. With a street price of $117.99 (9-23-2013) the Chinook Optical Tachometer G2 is not cheap but then nothing of good quality is any more. The fact that the Chinook Optical Tachometer G2 is high in quality, very accurate and does something helicopter people need makes it a must have for me.
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