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Old Dec 08, 2007, 04:22 AM
Model Bender
OzDragonFlyer's Avatar
Australia, NSW, Newcastle
Joined Jun 2004
2,870 Posts
must've just missed you Steve, got there at almost 12.30 exactly. Had the whole hill to myself for over an hour, before Fred & Alan arrived
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Old Dec 10, 2007, 08:01 PM
If it flies - it's good
Fred_L's Avatar
Australia, NSW, Sydney
Joined Sep 2003
1,145 Posts
Steve,
Don't feel bad, on Saturday the wind didn't shift all afternoon. We flew on the Sydney slope and the wind was square on that hill all the time. There was no hint that there was any need to relocate to the pie shop hill.

I stopped by at Otford yesterday afternoon but the wind was very much from the South making the lift poor. I had a short fly and then it started raining, so it wasn't worth hanging around.
F
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Old Dec 10, 2007, 10:19 PM
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GregK's Avatar
Cronulla, Sydney, Australia
Joined Apr 2007
189 Posts
Hey Fred, I was keen to get there on Saturday, but the BOM was saying straight Sth at best all day so I didn't bother. Do you think a). the lift is ok there straight Sth or b). the BOM got it wrong and there was a touch of E in it?
i am missing alot of days down there at the moment due to either the forecast, or the BOM readings of the day.
Thanks
Greg K
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Old Dec 10, 2007, 10:49 PM
If it flies - it's good
Fred_L's Avatar
Australia, NSW, Sydney
Joined Sep 2003
1,145 Posts
Greg,
The BOM got it a little wrong. I have been chastised here previously for thinking that teams of guys with doctorates and multiple supercomputers might be able to forecast the wind, or the weather generally. OK, it is an inexact science.

I look at the boating forecast on the BOM site as it provides graphical representations of wind on weekend days, both inshore and off shore. The times of the forecasts are 5am, 11am, 5pm and 11pm. This at least lets you extrapolate between the 11am and 5 pm forecast.

As many have noted before, the forecast winds on the boating forecast are usually stronger than what eventually happens and the suspicion is that they are covering their backsides should it actually be stronger than forecast, people get lost at sea and those wishing to direct liability put the BOM in their sights.

So it's a guide only. On Saturday the S going through E to NE didn't quite happen during daylight hours as it was S-SE only. The SE provided lovely smooth lift at the Sydney end during the mid to late afternoon period.

Is Otford flyable in a S wind? Ah... yes, but it is usually ugly. The air is sliding along the hill more than up and over it, so it is very turbulent due to the upwind bumps in the hill and and the vegetation. The lift is weak and if the wind is strong you are pointing into the wind with little lift so your options to play around are limited.

The Sydney end slope points 135 magnetic, which is dead SE. The pie shop hill points 100 degrees magnetic, which is a little south of east, so a ESE or E works well there. NE winds are bad, like S winds.
F
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Old Dec 11, 2007, 12:10 AM
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GregK's Avatar
Cronulla, Sydney, Australia
Joined Apr 2007
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Fred,
I looked at the BOM coastal weather observations on Sat night. It gives you a history for the whole day wind direction and strength at half hour intervals for the entire day. For Saturday it said either SSW or S for Belambi, Wattamolla, Kurnell and Sydney airport. There was not one reading from the SE, or for that matter SSE even for the entire area! So I was suprised to hear that you flew most of the afternoon in a good SE breeze, because the BOM definately didn't register it!?
that's why I was wondering if you flew there and it was Sth ( as the BOM said) or SE and the BOM missed it?
Just looking again today - same sort of breeze - SSW to S for all areas and checked flystanwell.com and it was saying SE at 132 degrees!
what am I missing? or should I say what is the BOM missing? Must be some sort of local wind shift for that part of the coast ? due to it's shape ? or due to the compression / interference of the wind up the slope??
Any ideas anyone?
GReg K
P.S I guess I answered my own question - the BOM isn't accurate for Stanwell in a Southerly?
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Old Dec 11, 2007, 04:49 PM
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OzDragonFlyer's Avatar
Australia, NSW, Newcastle
Joined Jun 2004
2,870 Posts
Don't believe any of those closer south coast w/stations.. the geography around their locations must swirl the wind a little and they aren't at all accurate.

Before stanwell w/station was finished, I simply added a safety factor of about 10 deg N to the Belambi & Pt Perpendicular ones to save wasted trips to the slope. Many times they've stated ENE and Otford has been NE and almost unflyable.
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Old Dec 11, 2007, 05:16 PM
I'm torquing to you!
Mr Kamikaze's Avatar
Wattle Grove NSW Australia
Joined Nov 2006
7,393 Posts
FlyStanwell says its sse to se right now at 30-40kph. I'm going down for a fly and will arrive around 11-11:30 if anyone is free
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Old Dec 11, 2007, 08:13 PM
If it flies - it's good
Fred_L's Avatar
Australia, NSW, Sydney
Joined Sep 2003
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Greg,

I understand your frustration. In my experience the wind on the hill is a little different to the wind you can see out on the water and also from what is reported by the weather stations. I find that it is usually squarer on the hill, particularly the Sydney end, than the external indicators would lead you to believe. This holds for winds from the South or East at the Sydney end. The hill appears to make it 'square up'. Is this the equivalent of refraction you can see in water and light waves?
So a southerly is experienced more as a SE or SSE and an Easterly also is felt to be more ESE or SE. When at the Sydney end a SE wind might go around to the East and unless you fly around the corner over 'Death Valley' and test the lift there you might be unaware that it is probably better at the Pie Shop hill and time to relocate operations.

Gosh, I am looking forward to those warm Sunday afternoons with a fresh ESE on the Pie Shop hill and planes bumping into each other all over the place.
F
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Old Dec 11, 2007, 10:09 PM
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Cronulla, Sydney, Australia
Joined Apr 2007
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Fred,
I have to agree, it is generally better down there than the weather sites would lead you to believe. In my time sailing we were told that as wind hit turbulance eg trees, grass, houses, it slows and therefore turns clockwise ( ie right as you look into the breeze). But I don't know what happens when it compresses from going up a hill. I would have to say it generally is windier at the top of a hill - so therefore the opposite would happen and it would go anti-clockwise ( ie left ). But then it also likes to follow coastlines, and valleys, and it might just be that Otford and Stanwell park due to their geography tend to turn the breeze squarer onto them?
Either way, I think I have to make the trip more often and find out for myself!
Talking of which, I am going to be down there from 3pm tomorrow if anyone else is interested. Looks like being a top day for it
Thanks for your input Fred.
Greg K
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Old Dec 12, 2007, 03:31 AM
I'm torquing to you!
Mr Kamikaze's Avatar
Wattle Grove NSW Australia
Joined Nov 2006
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Conditions were pretty good today. Matt and I flew from about 11:30 and when I left at 2:30 he still had a bird in the air. Another guy had also turned up and was flying a nice PSS FW190.

I got my Fatboy Wing, CS Mustang and my little electric power F4U Corsair in the air. Only used the power on launch and if it got in "trouble" oh and to chase off the hawks that kept harassing us all day.

We also had some impromptu combat, well we were zinging around close to each other anyway. Got one tag in when Matts Bat came at the Fatboy and tagged it from behind, but it pushed over into a spiral dive that couldn't be saved. Was great fun and I'd really like to get up there with 4 or 5 guys trying to knock each other out.

I understand few guys are heading up tomorrow arvo. Hope I can make it. And I hope the hawks are there again.
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Old Dec 12, 2007, 04:49 PM
If it flies - it's good
Fred_L's Avatar
Australia, NSW, Sydney
Joined Sep 2003
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A hawk was around on Saturday too. While it makes passes at the planes it doesn't hit them and I found that if you just relax it hangs around a while then moves off.
F
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Old Dec 12, 2007, 05:33 PM
Lame-As The real alternative!
narcas's Avatar
Bulli, Australia
Joined Nov 2006
4,181 Posts
The hawks only seemed interested in Brett's Corsair and my Bird. They didn't seem to mind the wings or the 'stang. The 'schmitt the other guy Tony had really moved with a thinned RG14, balsa over foam wing and an EPP fuse, ballasted off its nut. It wasn't too far off the pace off the Bird in normal circuits.

For those planning to head down today, the rain has been pretty constant all morning down here and the SE'er has only been gusting in with the heavy rain fronts. Hope things improve.
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Old Dec 13, 2007, 02:56 AM
<< Let's go sloping >>
Moth Man's Avatar
Caringbah
Joined Jan 2007
133 Posts
Quote:
Originally Posted by narcas
For those planning to head down today, the rain has been pretty constant all morning down here and the SE'er has only been gusting in with the heavy rain fronts. Hope things improve.
Well things did improve!! Greg K had a great afternoon with quite a few flyers coming and going. I got there around 4 and didn't leave till after 7.
Matt, thanks for the fly of your Bird. It certainly goes like a jet & sounds like one too. It's inspired me to get my Swift assembled & flying.
Was a great afternoon with good winds on the Pie Shop end.
Tim
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Old Dec 13, 2007, 04:10 AM
I'm torquing to you!
Mr Kamikaze's Avatar
Wattle Grove NSW Australia
Joined Nov 2006
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I have to say a big thanks as well to Greg and Tim for giving me a fly of your Speedos. Pretty darn good for $80 airframes! Was another great afternoon.
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Old Dec 13, 2007, 05:14 AM
The Glider Version
flatstick's Avatar
Liverpool, Sydney
Joined Mar 2007
1,257 Posts
Mr Kamikaze, You got to fly Tim's Original Speedo Thermo and
Greg K's Speedo Thermo II..... could you tell any difference between them.?
[ I bet you are asking....are they different?]
Glenn.
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