Folks,
One very old style peak "G" indicator can be built
by most anyone. Start with homogenious material such as
wood with no knots, solid steel, solid aluminum, solid
plastic or whatever. Form the material into a square
cross section with unit length sides. The "units" used
do not matter, except for the ultimate size of the G machine.
Cut blocks of the material with various heights. All
surfaces should be square and smooth. Now build a flat and level
surface big enough to hold all the blocks side by side,
(but not touching each other). Add a small strip to the
trailing edge of the mounting surface. Each block will be
placed up against the strip to keep it from sliding during
acceleration. ( A big strip will cause loss of accurcy in this
G Machine.)
Now the fun, A block 1 unit tall and 1 Unit square
(or 1 unit in the direction the Tiger will be going)
will tip over at 1 G. A block 1/2 unit Tall and 1 Unit square
will tip over at 2 Gs. Likewise a block 3 Units tall and 1 Unit
square will tip at .333 G. Get the picture: Base size/height = G
value that the block will tip ( neglecting a small error due to the
small strip that keeps the blocks from sliding.)
So If one makes a series of blocks of various heights,
Mark them with the base/height ratio, set them on the flat
and level surface. When you accelerate, all blocks that have
a ratio less than your peak acceleration will tip over. The ratio
of the last one to tip will give the peak G reading. Actually
( >=Last tipped ratio and < next untipped ratio ).
Note that the ratio is what counts, so the "unit" size of the
blocks could vary within the same G Machine.
Also note that the "width" of the block does not have to
be 1 unit.
Now go get your saws and sandpaper....
Given G from a bunch of blocks, V from speedometer and weight
of the Tiger you too can compute your peak HP. This provides
the true HP used to accelerate the Tiger. The computed HP will
always be less than engine dyno and/or rear wheel dyno because
drag from the air, rolling friction, etc are not used to accelerate
the Tiger.
If you have a very hot Tiger I suggest a series of ratios of
.7 to 1. Most anyone can pull .3 G in normal traffic so
you should not waste you time with the lower ratios unless
you want a lap full of blocks all the time.
At 09:08 AM 2/22/2001 -0800, you wrote:
>Hi Guys,
>
>Hope this gets through, as I have been off the main list, and on the
>digest, since my ISP went flaky. Getting a cable modem and new address
>this week, when I will "re-up" at high speed.
>
>Meanwhile, getting quite a kick out of the "when to shift" thread. With
>the new "G" meters, and even the old "Tapley acceleration instruments"
>from the old Road & Track test days, the one I like the best is the MOB
>meter (sometimes known as SOP meter).
>
>The MOB meter is portable, uses no batteries, is perfectly calibrated,
>and always accurate - if you know how to read it. By using the change
>in relative indications between varying shift rpm's, and choosing the
>indication that provides a higher indication on a shift, than the
>previous gear indication, will guarantee finding the best shift point
>for your car, your engine, your transmission, your tires, and your rear
>axle.
>
>When the indicated acceleration is greater in the next gear, than the
>one you just left, you are winning. when it is lower, you are loosing.
>Easy.
>
>Where can I get the MOB (SOP) meter?
>
>Well, some are better calibrated and more sensitive than others, and
>some drivers are quicker and finding the correct measurement
>difference. The MOB is "Middle Of Back", and the SOP is "Seat Of
>Pants".
>
>Very inexpensive, and portable too. Calibration services are available.
>Batteries not included.
>
>{9->
>
>Steve
>
>--
>Steve Laifman < Find out what is most >
>B9472289 < important in your life >
> < and don't let it get away!>
>
>http://www.TigersUnited.com/gallery/SteveLaifman.asp
>
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James Barrett Tiger II 351C and others
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