Re: Aircraft Tacho

This is a useful item. I have the Cermark and it has been flawless for
around 7 years. Uses a 9v alkaline and can read RPM from a foot away in
bright light.
Reply to
Paul McIntosh
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I recently bought a Thunder Tiger jobby for about £25.00. In good sunlight work from about 6 inches, seems to produce consistent numbers and does both 2 and 3 bladed props. Runs off a 9V PP3. Happy with it for the money. Only thing I have noticed it it doesnt work well under lights that have dimmer switches on, why i dunno, but claims 3100 despite my zagi doing closer to 17K! But in natural light it faultless. Got it from Als hobbies, but dunno if they are they cheapest place...
Reply to
Tom
It won't work under artificial lights because they aren't a constant source. They are actually flickering to the beat of the electrical frequency!
Reply to
Paul McIntosh
Isnt a way to check an optical tacho for accuracy to point it at a flourescent tube?? It should read 3000 i believe.
John.
Reply to
John Duxbury
Don't get the hobbico one. It runs on 4 watch batteries, and if you forget to turn it off overnight, in the morning you have to buy new batteries. About $14 worth. I did this twice before I ripped it apart and made a connector so it would run off a reciever pack which I could recharge.
Reply to
Normen Strobel
3000 un the UK and other places outside the US. 3600 in the US.
Reply to
Paul McIntosh
good point kinds works out rightish. 50Hz x 60seconds 3000RPM! OOOPS *feels kinda dumb :)* So according to that the Thunder tiger is at worst 3% off, I can live with that kind of inaccuracy :)
Reply to
Tom
I was referring to the fact that he couldn't read the prop RPM under artificial light.
Reply to
Paul McIntosh
In the US, 60HZ flickers 3600 times per minute [60 * 60]
Isnt a way to check an optical tacho for accuracy to point it at a flourescent tube?? It should read 3000 i believe.
John.
Reply to
Carrell
TNC makes the best tach on the market.
opinions will vary, jk
Reply to
jnkessler
actually, the light flickers at 7200 per minute, if your tach is set for 2 blade prop it will read 3600
bob
Reply to
Bob Cowell
actually, the light flickers at 7200 per minute, if your tach is set for 2 blade prop it will read 3600
bob
================================================ I guess that would be true. I just knew my Globe teach reads 3600 in my garage.
Reply to
Carrell
Mine runs on 2 AAA batteries - they must have learned a lesson about battery costs.
David
>Don't get the hobbico one. It runs on 4 watch batteries, and if you forget >to turn it off overnight, in the morning you have to buy new batteries. >About $14 worth. I did this twice before I ripped it apart and made a >connector so it would run off a reciever pack which I could recharge. > >-- >Normen Strobel > snipped-for-privacy@zoominternet.nospam.net > >
>> Hi, >> >> I'm considering getting a tacho for airplane use and I'd be grateful for >> the groups opinions on which brand is the best and which are the ones to >> avoid ? >> >> Thanks, >> >> -- >> Boo >> > > > > >
Reply to
David AMA40795 / KC5UH
All they had to do was put in a 5 minute auto shutoff, for idiots like me.
Reply to
Normen Strobel
Fairly sure John is in the UK.
*Very* roughly, North/Central/South America (but not Argentina, Chile), Western Japan use ~110v, 60Hz Europe, Asia, Africa, Australasia use ~220v, 50Hz
Reply to
John Privett
Actually, you got themaths wrong. 50hz x60 seconds time TWO PULSES PER CYCLE= 6000, but tachos expect TWO bladed props, so right answer, wrong maths :-)
Reply to
The Natural Philosopher
60 hz flickers at double that. The bulbs - or neons - light up twice per cycle.
The flicker frequency is actually 120Hz
Reply to
The Natural Philosopher
I had to think about this for a bit, but the reason there are 7200 (or 6000) flickers of the bulb is because you get one for each peak on the sine wave input. As the wave reaches peak positive, you get a blink. When it then goes negative and reaches peak, you get another with the current "going the other way" and so on. Bassically, you get two peaks for each cycle. Mark
Reply to
Penguin254
Europe is standardising on 230V 50Hz, but currently have 220,230 and 240. All countries are all theoretically moving to 230, I say theoretically because we actually have tolerances wide enough to allow countries to stay exactly where they are if they wish, now there's a diplomatic solution for you 8-). New products have to cope with the range so it's all academic really.
Greg
Reply to
Greg
But what would idiots do with idiot-proof stuff
David
>All they had to do was put in a 5 minute auto shutoff, for idiots like me. > >-- >Normen Strobel > snipped-for-privacy@zoominternet.nospam.net > >
>> Mine runs on 2 AAA batteries - they must have learned a lesson about >> battery costs. >> >> David >> >> >> >> >Don't get the hobbico one. It runs on 4 watch batteries, and if you >forget >> >to turn it off overnight, in the morning you have to buy new batteries. >> >About $14 worth. I did this twice before I ripped it apart and made a >> >connector so it would run off a reciever pack which I could recharge. >> > >> >-- >> >Normen Strobel >> > snipped-for-privacy@zoominternet.nospam.net >> > >> >
>> >> Hi, >> >> >> >> I'm considering getting a tacho for airplane use and I'd be grateful >for >> >> the groups opinions on which brand is the best and which are the ones >to >> >> avoid ? >> >> >> >> Thanks, >> >> >> >> -- >> >> Boo >> >> >> > >> > >> > >> > >> >
Reply to
David AMA40795 / KC5UH

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