The Alfatross came with a strange looking instrument bearing the label "DynoMeter." Former owner Pat Braden writes in his book Alfa Romeo All-Alloy Twin Cam Companion 1954-1994 that the man he sold it to (the man I bought it from) "never knew the car carried an (originally fitted) accelerometer." I think the DynoMeter is the accelerometer that Braden was talking about. How he knew it was "originally fitted," and exactly what that phrase means is a mystery. To the best of my recollection, when I bought The Alfatross 46 years ago it was included, but no longer attached.
I puzzled over this thing for many years. What does it do? How exactly does it work? Where and how is it supposed to be mounted? Why can't I find any information about it? Is this the only one left in the world? Is it another mute, but tantalizing indicator of race history?
Thanks to the indefatigable efforts of Jeff Kramer, Internet Nightcrawler, we now have answers to some of those questions--but by no means all.
The steel housing is surrounded by a chrome band with a peculiar clamp. Both detach easily from the dial face and inner body. No clues there.
Only the dial face hints at who made it and what it does. Starting in the middle of the dial we see that it is called a "DynoMeter" and it appears to have been manufactured by a company called Burg. The Burg name is written in script over a logo that appears to depict a pendulum suspended over a graduated arc. This is an important clue. The device appears to be patented "PATENTE ANG.", but where?
All the text is in Italian, but it could have been produced anywhere with dial faces appropriate for the market. At first glance, it could be mistaken for an item from the Italian equivalent of the J.C. Whitney catalog, but on further close inspection there is more than meets the eye.
This might get a little tedious, but I just want to point out some details that are easy to miss if you aren't paying close attention.
The dial face is divided into four bands encircling the pivot point for the needle. The outermost and innermost bands are symmetrical circular bands, but the two between them taper as they spiral around the dial face.
The outer black band is evenly divided into 80 increments representing percentages of G-force, and numbered 0 to 40 % reading from top to bottom clockwise and counterclockwise respectively. Note that the outer band is labelled "discesa" (deceleration) left of the zero point at the top of the band, and "salita" (acceleration) right of the zero point. Are you following this? Good, because it's about to get complicated.
The largest text is at the top of the dial face. On the left is the word "FRENO," meaning "brake." It is in white letters on a black band. An arrow beneath it points in a counterclockwise direction. To the right of the 0 point at the top of the dial is the word "MOTORE, meaning "engine," in black letters over a white background. And in the middle, between them, is the word "FOLLE" in red script, meaning something like "don't even think about it." These comprise the second and third bands.
In addition to the percentage increments around the outside of the dial face band 2, the white band just inside it, is numbered clockwise 1 through 4 from top to bottom in meters per second squared. Although the numbering stops at 4 at the bottom of the dial, there is one incremental mark beyond the 4. The black band inside the white one is labelled counterclockwise 1 through 8 meters per second squared. Note that the distance between graduations decreases dramatically.
The fourth band is labelled and graduated somewhat vaguely compared to the others. All of the left side of the band and part of the right side are labelled "insufficient" in white letters on a white background and the remainder of the right side is labelled "good" in white letters on a green background.
So what does all this tell us?
So now we're getting somewhere. Bowmonk was able to clean and repair The Alfatross' DynoMeter and refill it with the anti-vibration fluid, which had leaked out long ago . . . but they are just as much in the dark about the Burg company and this particular device as we are.
It is clear that we are missing part of the instrument's mounting apparatus, perhaps just a simple bracket. At some point in the not-too distant future we're going to install this thing in one of our vehicles and field test it to see how it actually works.
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| The Burg DynoMeter before restoration. The more you look at it the less you understand! |
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| Profile view of the DynoMeter. There are no connections, electrical or otherwise. |
Thanks to the indefatigable efforts of Jeff Kramer, Internet Nightcrawler, we now have answers to some of those questions--but by no means all.
Bands, Numbers, and Increments
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| The Burg logo appears to show a pendulum hanging from the top of a box with a graduated arc just below it: a simplified schematic of the mechanism inside? |
Only the dial face hints at who made it and what it does. Starting in the middle of the dial we see that it is called a "DynoMeter" and it appears to have been manufactured by a company called Burg. The Burg name is written in script over a logo that appears to depict a pendulum suspended over a graduated arc. This is an important clue. The device appears to be patented "PATENTE ANG.", but where?
All the text is in Italian, but it could have been produced anywhere with dial faces appropriate for the market. At first glance, it could be mistaken for an item from the Italian equivalent of the J.C. Whitney catalog, but on further close inspection there is more than meets the eye.
This might get a little tedious, but I just want to point out some details that are easy to miss if you aren't paying close attention.
The dial face is divided into four bands encircling the pivot point for the needle. The outermost and innermost bands are symmetrical circular bands, but the two between them taper as they spiral around the dial face.
 |
| Acceleration is measured on the white band in meters per second squared when the needle moves in a clockwise direction. Braking is measured similarly when the needle moves in a counterclockwise direction. |
The outer black band is evenly divided into 80 increments representing percentages of G-force, and numbered 0 to 40 % reading from top to bottom clockwise and counterclockwise respectively. Note that the outer band is labelled "discesa" (deceleration) left of the zero point at the top of the band, and "salita" (acceleration) right of the zero point. Are you following this? Good, because it's about to get complicated.
 |
| Acceleration and deceleration are measured in different ways on four information bands. |
The largest text is at the top of the dial face. On the left is the word "FRENO," meaning "brake." It is in white letters on a black band. An arrow beneath it points in a counterclockwise direction. To the right of the 0 point at the top of the dial is the word "MOTORE, meaning "engine," in black letters over a white background. And in the middle, between them, is the word "FOLLE" in red script, meaning something like "don't even think about it." These comprise the second and third bands.
The fourth band is labelled and graduated somewhat vaguely compared to the others. All of the left side of the band and part of the right side are labelled "insufficient" in white letters on a white background and the remainder of the right side is labelled "good" in white letters on a green background.
So what does all this tell us?
The Bowmonk Connection
Searching for information on dynometers, Jeff made contact with Mr. Ernie Hill at Bowmonk Ltd., the British manufacturer of Bowmonk Brakemeter/Dynometer, used primarily as brake testers (http://www.bowmonk.com/automotive/brakemeter). According to their literature their meter, which is substantially the same as the Burg,consists of a finely balanced pendulum free to respond to any changes in speed or angle, working through a quadrant gear train to rotate a needle round a dial. To damp out vibration, the instrument is filled with a special fluid not sensitive to changes in temperature. No maintenance is necessary.
The dial is calibrated in percentage "G", the accepted standard through the world for measuring acceleration and deceleration.
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| Here's a helpful little schematic and formula to help clarify the above statement. Say what? |
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| The Burg DynoMeter after cleaning and restoration by Bowmonk, Ltd. |
It is clear that we are missing part of the instrument's mounting apparatus, perhaps just a simple bracket. At some point in the not-too distant future we're going to install this thing in one of our vehicles and field test it to see how it actually works.
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| Bowmonk provided this certificate of calibration after restoring the Dynometer giving it a clean bill of health! |
