Without knowing the specifics of the site, I would think 500mm of gravel I
would be a bit of an overkill - we're not exactly dealing with high wheel
loads or tyre pressures in gliding operations. Have you done a reseal in the
20 years? If that's the original seal then it's a pretty good life - the
environmental effects (u/v degradation of the bitumen and oxidisation
leading to brittleness) would be what I would expect to kill the seal
eventually. Surprised that the tug operation would cause excessive wear on
the seal, unless they are pivoting hard on one wheel at the end of the roll
and screwing the stone out.
Do you recall if it was hot sprayed bitumen originally, or cold emulsion? (I
doubt that you actually used tar, which is a coal derivative and has not
been used in road sealing for yonks (notwithstanding some of the signs you
see beside the road), in part because of the superior performance of bitumen
(a petroleum derivative) but also because of its carcinogenic properties.)
Allan Armistead
Roads, Land Transport
(02) 6274 7677
"When once you have tasted flight, you will always walk with your eyes
turned skyward, for there you have been and there you will always be."
Leonardo da Vinci, 1452-1519.
-----Original Message-----
From: Ian K McPhee [mailto:[EMAIL PROTECTED]]
Sent: Friday, 23 March 2001 7:37
To: [EMAIL PROTECTED]
Subject: Re: [aus-soaring] Glider launching areas on your airstrip/aerodrome
About 20 years ago at Keepit we did the full on tar pads 400m x 6 or 8 m.
with 50cm dig out and gravel compaction. At the time it cost a bit more
than an LS4!! and we got half paid by sport & rec grant. We did a prime coat
and final coat 18 months later to spread the cost load. Fine stones were
bit of a problem for 3or 4 years although I would get the local council to
come out and sweep before a comps. The other positive is it gave a chance
for the rest of the strip to catch up and re grass. One problem is tug
pilots tend to go down the middle of tar at end and then we had a minor
problem at end of tar. I would remind tug pilots to go one side or the
other and most would forget - The only way is arrow near end of tar to
remind them! 400m is long enough except we were operating 100m in from end
of tar so careful placement is important. Back in late '70s we did think of
irrigation as Waikerie were doing at the time. Anyhow tar was expensive but
it was a good decision for the long term and all these days would agree I am
sure. Keepit in the late 70s and early 80s was a dust bowl.
Ian Mc Phee
Box 657 Byron Bay NSW 2481 Australia
Tel (61) 266 847 642 (Fax 942)
[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
www.mrsoaring.com <http://www.mrsoaring.com> for radios xponders
microphones wingstands instruments and much more
"If Flying were the langauge of man, Soaring would be its poetry"
----- Original Message -----
From: Roger <mailto:[EMAIL PROTECTED]> Druce
To: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
Sent: Wednesday, March 21, 2001 10:06 PM
Subject: [aus-soaring] Glider launching areas on your airstrip/aerodrome
I was thinking that perhaps there was some useful experience out in the
soaring electronic ether as to how other gliding sites have dealt with the
matter of resurfacing their glider take off areas. Is there some experience
which some of you may be able share with us? We have some ideas on what to
do but perhaps some sites have taken action and then had time to see how the
ideas actually worked out.
At Bacchus Marsh we have finally come to the stage where we have to act to
overcome the seriously rough ground at the two most used launch ends. Over
the past decade or so the Pawnees have tended to blast the ground with
propeller slipstream harder than the Super Cubs which early on were the only
tugs we had. Moreover the last four winters have been very dry which
certainly doesn't help. And yes it is going to be difficult to rest the
affected areas whilst the restoration work proceeds. Our aim is to achieve
smooth well grassed launch areas, probably grass all over but perhaps with a
bitumen launch strip inset.
We are aware of the effort at Locksley where the ground has been flattened
with a 'land plane' and the area(s) regrassed, and we will revisit there to
see again first hand and enquire more closely.
Some sites have put in bitumen take-off strips for glider launching, eg.
Benalla, Bathurst, Beverley (?). This appears to be a good idea at first
sight but does it work in the longer term? How long does it have to be?
What sort of width? What sort of cost? Whilst this approach deals with the
immediate take-off run, it still leaves one having to restore the grass
surrounding the bitumen strip. So are bitumen take-off strips cost
effective or is the money best spent on regrassing all over?
Have people succeeded in regrassing in dry land areas with minimal watering
or has it taken significant watering to establish the new grass? What sort
of grasses have been selected? We have had some advice as to native grasses
and exotic grasses which may suit but nevertheless it would be interesting
to know what others have used. Grass selection of course depends on local
conditions. Whilst we are in southern Victoria, nevertheless we are in a
low rainfall area at 18" average (450 mm) per year. As always this is
variable. We don't have an issue with flooding or waterlogging as there are
adequate gradients for drainage. Also we don't have a significant frost
problem which can be an issue for some grass types.
I realise I am not necessarily expressing all of the issues all that well,
but it is late at night.
It may be that an electronic reply has merit, or perhaps a real time human
to human telephone communication may be quicker and more direct. So I
append my telephone number.
Thanks in anticipation
Roger Druce
Tel: 03 9439 8947
Fax: 03 9431 4175
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