Van's Air Force
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Van's Tachometer
- Thread starter tporter
- Start date
luckyjack51
I'm New Here
Do you know who makes that digital/optical tach you mentioned in your post of 03/2006? Know it has been a long time, but my RV4 has one of those and I'm curious if the outfit that makes them is still in the business and has new ones or something "better."
RV7AV8R
Well Known Member
My digital optical tachometer is made by Apex Electronics. It's called a "TruTach".
I've had it for many years.
Aircraft Spruce currently carries the TruTach II for under $200.
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TACH VS HEAT
Greg and all
''I'm on my third tach generator in only 50 hours. ''
Your problem is most likely heat related...Install one or more (depending where you live) cooling blast tube that arrive just on top of your tachgen and you won't have any more problems..
I went thru 2 tachgen in short order before I happened to touch it and it was cooking...the cool air fixed the problem..
Good luck
Bruno
Greg and all
''I'm on my third tach generator in only 50 hours. ''
Your problem is most likely heat related...Install one or more (depending where you live) cooling blast tube that arrive just on top of your tachgen and you won't have any more problems..
I went thru 2 tachgen in short order before I happened to touch it and it was cooking...the cool air fixed the problem..
Good luck
Bruno
Strobe
One way to check your tach is to use the strobe effect which you will get from a flourescent light. You can check your rpm at sub-harmonics of 7200 rpm. This relies on the fact that the light output from the flourescent is not steady but pulses at 120 pps. An incandescent bulb will work, but just barely, since its light output is steadier than the flourescent. This test is best performed in a shady area or just after sunset. Night works best if you are in a lit area so that there is no safety problem when working near the prop. You might even be able to observe this from sodium-vapor or similar lamps providing apron lighting! At these sub-harmonics the prop will appear to stand still with varying numbers of blades. For instance, a two-blade prop will appear as four blades spaced 90 degrees apart and standing still at 1800 rpm. At 1200 rpm it will look like a six blade prop, with a blade every 60 degrees standing still. This is a fuzzy looking blade, not a sharp ouline, but it's the relative motion or lack of it that counts!
One way to check your tach is to use the strobe effect which you will get from a flourescent light. You can check your rpm at sub-harmonics of 7200 rpm. This relies on the fact that the light output from the flourescent is not steady but pulses at 120 pps. An incandescent bulb will work, but just barely, since its light output is steadier than the flourescent. This test is best performed in a shady area or just after sunset. Night works best if you are in a lit area so that there is no safety problem when working near the prop. You might even be able to observe this from sodium-vapor or similar lamps providing apron lighting! At these sub-harmonics the prop will appear to stand still with varying numbers of blades. For instance, a two-blade prop will appear as four blades spaced 90 degrees apart and standing still at 1800 rpm. At 1200 rpm it will look like a six blade prop, with a blade every 60 degrees standing still. This is a fuzzy looking blade, not a sharp ouline, but it's the relative motion or lack of it that counts!
Here is what you should have........................
1. ONE TOUCH DIGITAL TACHOMETER
This digital LCD tachometer reads 2, 3, or 4 blade props very accurately. Very easy to use and features auto-shutoff and 10 RPM readout.
http://www.aircraftspruce.com/catalog/inpages/onetouch.php - 1.0kb
10-00749 ONE TOUCH DIGITAL TACH CHECK + $36.50
Aircraft Spruce......
You can check your prop as you fly. And can confirm the accuracy of the prop check by pointing it at an ac current light. It will read 3600 rpm in two blade setting. It sees 60 cycles per second X 60 seconds to = one minute of cycles or rpm.
1. ONE TOUCH DIGITAL TACHOMETER
This digital LCD tachometer reads 2, 3, or 4 blade props very accurately. Very easy to use and features auto-shutoff and 10 RPM readout.
http://www.aircraftspruce.com/catalog/inpages/onetouch.php - 1.0kb
10-00749 ONE TOUCH DIGITAL TACH CHECK + $36.50
Aircraft Spruce......
You can check your prop as you fly. And can confirm the accuracy of the prop check by pointing it at an ac current light. It will read 3600 rpm in two blade setting. It sees 60 cycles per second X 60 seconds to = one minute of cycles or rpm.
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