Hi Terry,
I think for both clocks it was fully manual (as opposed to fully automatic), by
the use of the Mk 1 eyeball and a watch set to official time. In the first
case, on cue the appropriate valves would be manually opened or closed. In the
second case the panel team would manually either run-out or close-up the
appropriate panels. In the case of Benalla, Max said they did not always get
the timing exactly on cue, so they kept a log of the differences from official
time: Probably not more than 10 or 15 seconds max error, but this quanta is
speculation on my part. Max did say that he got himself another job part way
through the WGC at Benalla, so my guess is that the Ground Clock was not in
practice required/essential to the needs of the organization. Just my guess
though!
Gary
----- Original Message -----
From: Terry Neumann
To: Discussion of issues relating to Soaring in Australia.
Sent: Thursday, August 11, 2011 9:36 AM
Subject: Re: [Aus-soaring] Ground Clocks - a little bit of history
Thanks Gary, I was thinking about ringing Max myself to find out what
happened. Apologies for the mistake in the time period; sometimes my
forgettory works better than my memory :-[ And no, I didn't realise that
there was a second version built....
A couple of us have been speculating what he actually used as the time and
switching source for the whole project - i.e. what actually was FRED, because
an worthwhile computer of that era was far from the portable devices we take
for granted these days. There were enormous strides made in computer evolution
during that era, so with it being in the early 80's rather then the late 70's
as I earlier speculated, then something more 'commercial' might have been at
the heart of the system. Did he enlarge on that at all ??
regards,
Terry
On 10/08/2011 11:31 PM, gstev...@bigpond.com wrote:
Hi Terry,
Verrrry interesting.
I gave Max a call earlier tonight, and you are right!
Are you aware that he has built two of these infernal devices? He told me
building the Horsham one kept him amused for "weeks". His memories of the whole
thing are now a bit vague, but he obviously remembers the bits that proved to
be challenge - valves and controllers and such like, all built from scratch! He
has no photos, and all the surviving components were consigned to the
tip/recyclers about 12 months ago. It would seem that the scenario was much as
you described! Max was the builder and Wally Wallington provided the design
concepts - based on the Binary Theory you have referenced. Camera clocks were
just appearing on the scene at this point in time, and Max intimated that they
(and by inference, due to time required to phase out an older system), and the
conventional start gate method were used for the actual scoring of the
competition that year. Pick a date in the early eighties, rather than late
seventies as you have suggested, for this competition.
Max found that this particular project did not achieve its aim, due to the
fact that the panels, as constructed, were too small, and thus could not be
definitively photographed with the cameras in use at the time - Kodak
Instamatics almost invariably - from 1000 m above terrain. The panels were
square, and the size was either 2.5m or 3.0 m to a side - Max couldn't quite
ping it off the top of his head! .... pun? .... groan! The material used for
the panel cladding was mini-orb steel sheeting. Total cost to build the system
was "about $1000.00".
The 2nd Ground Clock that he built was for the WGC in Benalla. Once again
Wally Wallington (who was the Contest Director), provided the concepts, and Max
then did the work to put these concepts into reality. It would seem that this
clock is basically as described in the April '83 edition of AG. Max told me
that he provided a brief (one page?), description of the system in the WGC
notes of the time . If anybody has a copy of the document, please do download
it to this site . The essential changes here over the Horsham design were the
increase in panel size to 20 m X 3 m, and the construction of the panels out of
fabric. These panels could be opened and closed by sliding them along
supporting side wires. Three people could operate the system.
Again, it would appear that in the reality, all start times were taken from
the on board camera clocks, and the ground clock was not used, except in a
back-up situation, such as when the camera clock had failed to record a start -
a pilot finger problem always - he didn't press the right buttons - as a camera
failure would mean no record at all, of anything - bad luck buddy - zero points
for the day!
I suggest that it would be very possible - almost a sure thing - to get
grant money to build a replica of this device at the Gliding Museum (and a sure
way of slowing down the kids after they have run the panel sheets in and out a
few times), if the Museum Directors choose to take the idea onboard. I suspect
that Max would be delighted to act as Project Director (if asked), but of
course on the proviso that he was given total authority and control.
Cheers,
Gary
----- Original Message -----
From: Terry Neumann
To: Discussion of issues relating to Soaring in Australia.
Sent: Wednesday, August 10, 2011 10:26 AM
Subject: Re: [Aus-soaring] Ground Clocks - a little bit of history
Max Hedt invented and constructed a ground clock for use at Horsham Week
comps back in the last century - (very late 70's perhaps??)
As I recall - and it was back a while now - it used a system of
displaying the time using binary notation. It was impressive in its
complexity and brilliant in its design and construction.
The system used a master electronic contraption (computer?) called FRED*
to command (either open or close) a number of large blocks or frames of
horizontal shutters like those in a venetian blind. This was achieved by a
compressed air driven piston on each individual frame extending or retracting
as commanded by FRED and swinging the shutters in much the same way as a swell
box on a large pipe organ.
If the shutters on a particular frame were closed, it appeared as a solid
block and represented the binary digit 1. Blocks which were open appeared
largely transparent from the air and represented the binary number 0. The
whole contraption was large enough - several hundreds of square metres in area
- to be photographed with sufficient definition from the start height, and
later to be decoded as an actual starting time by the verifier, possibly Max
himself or the late Geoff Champlain.
To be at the site itself when the thing was in operation was a mind
blowing experience with the petrol driven air compressor and FRED in the midst
of the multiple frame assemblies supporting the shutters. Every so often the
sequence would change, the shutters on some frames would close - others would
clang open - all with mechanical sounds, accompanied by that of compressed air
energising the pistons or venting from then. It's possible that wildlife at
Horsham still avoid that area ;-)
It must have taken hundreds of hours to design and build. I often
wonder what happened to it; there must be photos of this somewhere.
Incidently, you can see how a binary clock operates, and what it looks
like here Quite fascinating.
Regards
TN
E & OE
* FRED is/was an acronym which has been used elsewhere in scientific and
electronic literature. Google can be your friend if you don't know what it
stands for but would really like to ..... ;-) Most electronic enthusiasts
have a FRED or two in their collection.
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