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Old Dec 12, 2012, 05:19 PM
Registered User
United States, CA, Santa Monica
Joined Nov 2012
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How to identify a good slope?

How do you identify a good slope?

What are the necessary parameters and conditions that make a good spot? Would this be a good one?

I'm totally new to sailplanes but not new to wind (prof. sailor) and happened to be in my old stomping grounds, love walking around here and I think this could be great spot? I've searched on the forums but didn't anything that was straight forward.

Great angles, there's soft beach below, shear drop and serious up draft, just not sure if the landing zone on top of the cliff is acceptable (see pic) and if the wind flow (more than 4kts) is good but there are always birds floating at this spot compared most places in the area that look similar.




LZ, not big, (low trees and taller bushes about 100' inland, not shown):


This is where you would stand:




For years when I go surfing here there would always be birds soaring off the lifts at this specific spot. The whole coast is littered with cliffs at different angles but this is where they love to float.

When I was a younger, we would stand on the edge holding our jackets open as if the wind could pick you up and fly.

There's a precarious slippery trail to the beach that takes 1min from this spot and a much better one that isn't precious that takes 10mins to walk if you needed to get your plane off the beach. The temperature drops near the cliffs, moisture in the air increases and the wind is very dense in spot compared to other places along the cliffs.
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Old Dec 12, 2012, 05:26 PM
Silent Flight
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United States, CA, Cypress
Joined Jul 2005
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Looks like an awesome site. If you are unsure about the landing start with an EPP plane or something that can stand abuse a bit.

-Jonathan

EDIT: Whats behind the slope or LZ picture? The grass area looks acceptable but it would depend on your direction of approach.
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Old Dec 12, 2012, 05:28 PM
Silent Flight
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Joined Jul 2005
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Where exactly is that by the way? Can you link a google map or google earth spot to it? I just noticed your Avatar says you are in Santa Monica.

-Jonathan
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Old Dec 12, 2012, 05:36 PM
Crikey never leave beer behind
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Mt Annan Sydney Australia
Joined Dec 2003
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I usually find that sheer cliff faces have a pretty horrible rotor on the lip but out past that is good , just have to remember the rotor on approach to land
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Old Dec 12, 2012, 05:38 PM
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United States, CA, San Clemente
Joined Feb 2008
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Birds are usually a good sign, take a test plane and chuck it!!
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Old Dec 12, 2012, 06:30 PM
Silent Flight
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It's been a long time since I've driven by Santa Monica, but I know people fly off of Temescal Cliff near PCH and Temescal Canyon. That said, I really like the pics you posted and am curious where that is.



-Jonathan
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Old Dec 12, 2012, 06:40 PM
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United States, CA, Santa Monica
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I think I'll have to agree with the wash, standing near the edge the wind a couple of feet inland is quite violent and disturberd hence the question about the LZ. Further back is a row of trees but after that is miles of flat farm land

It's not in So Cal, it's in Santa Cruz County. I wish I had a plane with me but I'll be coming back many times. This spot is prettier than Waddell but unsure if it's better for sailplanes.
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Old Dec 12, 2012, 06:46 PM
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United States, CA, Santa Monica
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Quote:
Originally Posted by Twyl View Post
It's been a long time since I've driven by Santa Monica, but I know people fly off of Temescal Cliff near PCH and Temescal Canyon. That said, I really like the pics you posted and am curious where that is.

-Jonathan
I grew up at temescal cliffs and it's a whole different ball of wax compared to this spot. I'm going out there now again for a hike, may take some more photos
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Old Dec 12, 2012, 07:00 PM
Silent Flight
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United States, CA, Cypress
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My Grand parents lived in Santa Cruz and I've been there a number of times. I have to agree there is some pretty country around there. Am I correct in guessing the slope is north of the city? I'm sure there are plenty of SC slopers that could help you out if you liked, but as long as the wind direction is good, I'd don't think you'd have too big of a problem tossing a Radian or something off there.

You can also check out www.slople.com to see if there are any previously identified slopes in the area. Take the data from the above link with a grain of salt, it's not always the most accurate.

-Jonathan
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Old Dec 13, 2012, 02:37 AM
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United States, CA, Big Bear Lake
Joined Nov 2007
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That place looks great. Fly in that little bowl and you're sure to find some pretty solid air.
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Old Dec 15, 2012, 07:53 PM
Ochroma Lagopus Tekton
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Blackstock, South Carolina
Joined Sep 2007
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Is there a minimum gradient for sloping? My club's flying field is atop an old landfill with a good uninterrupted 100 feet elevation gain from the bottom of the canyon, and facing into the prevailing wind to boot, but it's a long way from being a cliff face.
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Old Dec 15, 2012, 08:40 PM
Crikey never leave beer behind
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Mt Annan Sydney Australia
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Then its just about perfect I guess a 45 to 60 deg slope is really optimum but definitely not needed
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Old Dec 15, 2012, 08:45 PM
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Quote:
Originally Posted by Fly Wheel View Post
Is there a minimum gradient for sloping? My club's flying field is atop an old landfill with a good uninterrupted 100 feet elevation gain from the bottom of the canyon, and facing into the prevailing wind to boot, but it's a long way from being a cliff face.
Somebody correct me if I'm wrong but I believe anything more than 30 degrees but obviously the steeper the better but you will really need the wind to be head on and not at an angle.
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Old Dec 15, 2012, 08:56 PM
Crikey never leave beer behind
steve wenban's Avatar
Mt Annan Sydney Australia
Joined Dec 2003
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This give the perfect example of just how littl is needed
http://www.rcgroups.com/forums/showp...&postcount=311
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Old Dec 15, 2012, 10:40 PM
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Lakewood, Colorado
Joined Aug 2002
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What most people think of as "about 45 degrees" is usually more like 25-30 degrees,
and you can slope on even less than that. 45 degrees feels uncomfortably steep to most
people (like if you tripped, you'd roll to the bottom, kind of steep).
And yes, built up landfills will work. There's a famous one "Mount Trashmore" in Florida
and a couple others that people fly around the country. Lower angle slopes tend to need a
little more vertical draw, slippery planes and medium to light winds straight in. If the wind
is off angle, they don't work. They're also easily blown out with higher winds.
By comparison, a true 45 degree slope will support heavy planes in very light winds, and
go totally ballistic in big winds. Vertical slopes will do the same, but then landing can
become a serious challenge. We have one slope that has a 600 foot draw at about 35
degrees and the last 40 feet are vertical. I've gone 158mph in a frontside dive there. In
a 40mph wind, it can be dead quiet 15 feet back from the lip and can hear the planes
whooshing around 200 yards away. The problem is, the rotor behind the lip extends
back 200+ yards, so have to get the plane really high, while walking backwards
for 100 yards, then bring it high high overhead downwind another 200 yards past that
(all while continuing to walk downwind), dive straight down, and scoot it in under the
rotor and land with some decent forward momentum to avoid getting flipped over by turbulence
200 yards back from the lip.

ian
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