Vibra-Tak...Old School Tachometer...GOT ME ONE !!!!!!!

SuperDave wrote:Kim:

Didn't have one either but I remember them as operating like a tuning fork for a piano with a scale indicating the resonance as RPM.

PRIMATIVE in today's context of tachometers. But that's the way most things originate.

PRIMITIVE ??!! HEY ! It says "Highly Accurate" !!!! So, figure the user held it close to the prop or twanged it or something? I got a notion that when I find out how it WAS used, I'm gonna get that "really dufus" feeling again...!

Think now, I got to have one....

Kim wrote:

SuperDave wrote:Kim:

Didn't have one either but I remember them as operating like a tuning fork for a piano with a scale indicating the resonance as RPM.

PRIMATIVE in today's context of tachometers. But that's the way most things originate.

PRIMITIVE ??!! HEY ! It says "Highly Accurate" !!!! So, figure the user held it close to the prop or twanged it or something? I got a notion that when I find out how it WAS used, I'm gonna get that "really dufus" feeling again...!

Think now, I got to have one....

http://www.vibra-tak.com/products.html#SLIDE-RULE%20TACHOMETER

"Highly accurate" compaired to what?

WELL HOOT INDRA !!!! Thank you ! NOW...to solve the mystery and finally become a "Serious Engine Dude" !!!!!!!!!!!!

You guys are something....

SuperDave wrote:"Highly accurate" compaired to what?

Well...compared to ones that are "Lowly Accurate" of course !

The suckers are going for $33.95....MAN ! What a difference 44 years makes ! Who'd a thunk it ???!!!

Still don't see how it actually works. Does it come with a graph that you can plot? I assume it has some sort of scale built into the tool itself?

I like it though as it is multi-faceted.

I have a probe type stethescope that is a great tool in finding the source of ticks grumblings and wobbles in auto/cycle engines. It too is "old school" sometimes simple is good too.

cribbs74 wrote:Still don't see how it actually works. Does it come with a graph that you can plot? I assume it has some sort of scale built into the tool itself?

I like it though as it is multi-faceted.

I have a probe type stethescope that is a great tool in finding the source of ticks grumblings and wobbles in auto/cycle engines. It too is "old school" sometimes simple is good too.

Well, we're gonna find out....got to get one of these...if for nothing else...to hang in it's holster (remember the Slide-Rule Holsters??!!)...on the wall and Inspire me to do Great Things !

Oh, great!

Now the "nerds" have infested the Cox hobby!! "Pocket-protectors" will be next!

Yeah...as opposed to all those Dashing Jocks that PREVIOUSLY made up the Cox Hobby!

I think you must have to stick this thing against the engine case or something...

It's small size enables accurate readings to be taken even on hard-to-reach equipment. Deep-etched scale gives direct readings from 2000 to 21,000 ... higher speeds, register and can be closely estimated. VIBRA-TAK will not show RPM of completely vibrationless rotating parts and will not pick up speed of motors running under 2,000 RPM.

Kim wrote:
....got to get one of these...if for nothing else...to hang in it's holster (remember the Slide-Rule Holsters??!!)...

SuperDave wrote:
....Now the "nerds" have infested the Cox hobby!! "Pocket-protectors" will be next!

Hey! I've got a sliderule holster and a pocket protector --- so bugger off you guys!

The tach works on the concept of fundamental frequency or natural frequency. When a vibration frequency matches the natural frequency of a plate or reed, the plate will vibrate more strongly. Most of us have experienced it or heard of situations where it could occur. If you slowly bring up the motor rpm on a riding mower, at some point you may notice that the deck seems to amplify the sound or the idea that a column of men marching across a bridge in step can cause it to vibrate. I have a helicopter that has a harmonic shake at a particular rotor rpm --- below and above that narrow range, it's pretty solid, but at about 1/3 throttle, it shakes like crazy.

By holding the vibra-tach against the engine and extending the reed to the point that it vibrates heavily, you can then calibrate the length of the reed to readings on the tach housing. It's not going to be highly accurate, but can be close.
Harmonics are tied to a lot of things we're exposed to everyday, and harmonic dampeners are designed to counter the tendency of items to items to hum or shake violently when the vibrations match the natural resonance of the product.

As an example, if we had a computer harddrive that tended to hum or be noisey when mounted, we found that sticking a wad of gum to the drive cover would quieten it down!

andrew

OK...makes sense !!!! Now, come here, you little high-revving prop slinger...I'm just gonna put this up against your backside...womp-whack!...the Flying Tach !!!!!

i tend to use PV Pilot /Keith's trusty Ear-Tach for analisys, it never fails!

GermanBeez wrote:i tend to use PV Pilot /Keith's trusty Ear-Tach for analisys, it never fails!

SEE!!,,told Ya!!!. Just keep your teeth really close together so's the harmoink's makes them click,,then wait for the reading to be wispered in your ear.

Dangit! me and my big mouth, was gonna use that method for this year's tach race entry

[quote="andrew"]

Kim wrote:


As an example, if we had a computer harddrive that tended to hum or be noisey when mounted, we found that sticking a wad of gum to the drive cover would quieten it down!

andrew

Ahhh...the ole "Gum Dampener" trick !

i just got an idea...
i did a frequency analisys of my golden bee video,
and it peaked at around 8600hz.
thats 8600 pops per second...
take that times 60 and...516000 RPMS! HAHA!
must've done something wrong, or my GB is incredibly awesome...

GermanBeez wrote:i just got an idea...
i did a frequency analisys of my golden bee video,
and it peaked at around 8600hz.
thats 8600 pops per second...
take that times 60 and...516000 RPMS! HAHA!
must've done something wrong, or my GB is incredibly awesome...

Don't quit you day job.

there we go, i just had to find the right diagram.
its 216 hz peak, so 215 pops per second.
multiply that by 60, and you get 12900 rpms!
awesome! dave, you're such a smart boy...

Kim wrote:OK...my latest mental-mistrack involves wanting to find out how this thing worked. When I was a kid, I figured that any model airplane dude worth his salt, just HAD to have one of these in his tool box... "the best performing engines are checked with the original Fowler VIBRA TAK"!

Thing was, it cost as much as a Babe Bee or good quality kit, so I never wagered my paper route money that it'd be worth buying.

So, I am once again tapping into the vast and growing pool of knowledge here and over in the .049 Collectors Group. Anybody ever use one (got one) of these? If so, how the heck did it work?

Now this REALLY takes me back, I remember these being on the market, but I had no idea that the things were still made!
As someone else has said, you held them against the engine and screwed the wire out until it began to viabrate, then read the revs off a scale on the barrel. In the UK the Aeromodeller Annual had an article once on making your own tach using different lengths of piano (Music) wire, if I remember correctly they had an incrediblely complicated graph to plot the length and thickness of each piece of wire to match a particular RPM, then you held it against the engine and watched which bit of wire viabrated most! Ahh, the good old days!!

Wilf

That add kinda reminds me of the pedometers you could buy out of the comic books. The device that told you how fast you walked or ran..

Got a call from a nice gentleman at Verdell Instruments today. Gonna get my Vibra Tak on the way here in a bit. There WILL a Pictorial Review !!!!

Between the recently acquired Goldberg "Ranger" and this little device, the Skunk Works is becoming a major Nostalgia Center !!!!!

awesome, kim!
say, have you got a YT channel?

Kim wrote:Between the recently acquired Goldberg "Ranger" and this little device, the Skunk Works is becoming a major Nostalgia Center !!!!!

The curator should fit right in!!