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How much wind needed for slope soaring?

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How much wind needed for slope soaring?

Old 05-16-2011, 12:00 PM
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stick man
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Default How much wind needed for slope soaring?

I just got my first glider (Discus 2.6m) and I want to maiden it soon. There are lots of hillsides where I live and usually wind, too. My question is; is there a genreal guideline regarding ideal wind cond?

How much is too much and how little is too little?
Old 05-16-2011, 01:01 PM
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wyowindworks
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Default RE: How much wind needed for slope soaring?

It really depends on the face of the slope. If the face is steep (45*) and tall (400 ft or more) you can fly in winds as light as 7 mph. If the face is lower angle and not very tall you will need more wind. Another factor is how much obstruction there is in front of the hill. If there other hills in front the wind may not "lay down" at the bottom of the hill so less upward air movement. The shape plays a part as well. A bowl shaped area tends to capture and direct the air straight up the hill while a round hill tends to direct some air around it. Long ridges work better than short ones.

Here is a little video of a steep bowl shaped hill I fly in light winds: Video 1 Note that I'm still flying a plane I don't have really care about. I'm also having to fly pretty close to the lip of the hill to stay in the rather small lift band. The wing loading of this place in around 7.5 ounce/sq. ft.

This video is of a steep large bowl shaped hill in 40 mph winds. In this video the 48" plane only weighs 19 ounces. If the hill wasn't as steep I'd have to add some weight. Since most of the air is direct up the light plane performs pretty nicely.

These a both excellent slopes so they should give you an idea of what to look for.

Old 05-16-2011, 01:14 PM
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flexsphincter
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Default RE: How much wind needed for slope soaring?

welcome to rc universe,,, your question depends on your plane,,i have flown with as little as 5mph on a slope and was able to "keep" my plane up..
it has much to do with the shape of your "slope" the wind direction to the face of slope,(consintrating wind/lift focus) and the weight of your plane to wing area...i think they call it "wing loading". im not very versed in the terminolagy and scientific words but i can speak threw my experiance of years of sloping albeit from mountain cliffs,mount trashmores, bumps in land scape, or off the side of a large building.. in va bch we have a "board walk" with 14 story hotels facing east for many city blocks/miles and with a good throw or bungie assist we can work the air up and down the board walk as it hits the east/ocean side of building. typically due east. lite wind ie. 5-10 mph equals light plane, 10- 35 mph means add some balast, or you will shurley hit a balcony loose plane or worse.... so i would say in short to answer too your question "it" depends on conditions and your plane and "any" lift is good lift .. now work to take advantage of the lift.. have fun
jeff
Old 05-16-2011, 01:33 PM
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stick man
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Default RE: How much wind needed for slope soaring?

Thanks, guys.

My plane is a Discus 2.6m. I'm not sure of the weight as I've yet to build it, but hoping to get to it this wknd. And as a newbie I think I need to stay away from urban areas, ha! I will look for a "bowl" shaped hillside in my area.

BTW I've been playing with a 9ft glider on the sim but it seems really hard to get lift on any terrain other than a hillside, no matter how much wind i dial in. Is this the way it is in reality or is there something off about the sim?
Old 05-16-2011, 06:46 PM
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Default RE: How much wind needed for slope soaring?

That plane is not for a newbie. Fly a wing around for a while and get a feeling for the lift bands, where they are at, and how strong they are.
Old 05-16-2011, 08:20 PM
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Default RE: How much wind needed for slope soaring?


ORIGINAL: TIA

That plane is not for a newbie. Fly a wing around for a while and get a feeling for the lift bands, where they are at, and how strong they are.
I agree. There are definately does and don't do slope flying....especially on a new slope. One poor decision could ruin your new glider. I think it's best to learn on something made from EPP.

Adam

Old 05-17-2011, 02:23 AM
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Default RE: How much wind needed for slope soaring?

I gree with Wyowindworks and TIA. That Discus of yours have very aerodynamic wings and will slope soar on a rat's breath. If not careful and if not having a nice clean landing area, you will find yourself in a catch 22 situation. As you try to lose height, you will gain airspeed, you try to lose airspeed you gainheight and the circle repeats itself.
You can side slip in but that is not easy and takes practice. Have you got spoilers/air brakesfitted perhaps?

Get a bottle of "soap bubbles" from a toy shop, then stand on the slope wher you intend to fly and make soap bubbles - then watch them go up slope and over into to dead zone.
This will give you a goodidea where turbulence and cleaner air is - especially the area where you plan to land the glider.

Happy landings
Bundu
Old 05-17-2011, 02:01 PM
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Default RE: How much wind needed for slope soaring?

Your second video is FANTASTIC!! What a rush!!

Nice flyin'!!

~Noah
Old 05-17-2011, 03:27 PM
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Default RE: How much wind needed for slope soaring?


ORIGINAL: OkadaKeisuke

Your second video is FANTASTIC!! What a rush!!

Nice flyin'!!

~Noah
Thanks. Once I started flying slope I sold everything that had a motor on it.. I love flying slope! It's pretty easy to get 2 or 3 hours of aggresive stick time in...no recharging batteries and refueling required. Western Wyoming helps out too.



Old 05-17-2011, 04:28 PM
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Default RE: How much wind needed for slope soaring?

I used to fly slope at Torry Pines and other great sites all over SoCal, but now I'm stuck in the FLAT midwest. So, no more slope flying for me.[&o] I miss slope flying
Old 05-17-2011, 05:19 PM
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Default RE: How much wind needed for slope soaring?

cfircav8r:

Did you ever run into Mike Hollison when you were at Torry Pines?


Old 05-17-2011, 06:00 PM
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Default RE: How much wind needed for slope soaring?

Sounds about right. Iwas already thinking of getting something a little more "expendable" to hone my skills with, this just confirms it. thanks for the input!

BTW can you recommend an inexpensive EPP?

ORIGINAL: wyowindworks


ORIGINAL: TIA

That plane is not for a newbie. Fly a wing around for a while and get a feeling for the lift bands, where they are at, and how strong they are.
I agree. There are definately does and don't do slope flying....especially on a new slope. One poor decision could ruin your new glider. I think it's best to learn on something made from EPP.

Adam

Old 05-17-2011, 08:23 PM
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wyowindworks
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Default RE: How much wind needed for slope soaring?


ORIGINAL: stick man

Sounds about right. Iwas already thinking of getting something a little more "expendable" to hone my skills with, this just confirms it. thanks for the input!

BTW can you recommend an inexpensive EPP?
Dream Flight Weasel
Leading Edge Gliders
Wyoming Wind Works Slope Monkey
L2 Airframes Super Scooter
Windrider Fox

Are a few for starters. Building an EPP kit does involve some labor. Probably the Weasel and the Fox involve the least.

Old 05-18-2011, 09:13 AM
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Default RE: How much wind needed for slope soaring?

ORIGINAL: Mustang Fever

cfircav8r:

Did you ever run into Mike Hollison when you were at Torry Pines?


Possibly, but i'm not good with names and I haven't been out there since '93.
Old 05-18-2011, 12:21 PM
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Default RE: How much wind needed for slope soaring?

That's OK. Thanks for the reply. I just remembered that he was talking about having flown at a Torrey Pines in Ontario.

He designed a 50" semi scale P-51 years ago, it appeared in RCM and the plans are still available. I built one and put a small electric motor in it so I can fly it around here. (No cliffs.) Someday I'll get to try sloping it. We go to a cottage in the Mich UP every summer that's at the east end of a lake that gets strong west winds. There's about a 40 foot vertical bluff at our end, and it forms sort of a half bowl, so maybe [:-]

I've never sloped before so I'm hoping the motor will keep me out of trouble if I blow it. My only real concern is that it's too heavy- the original design built out at 2 pound, and mine is 3, with a wing loading of over 18 oz per square foot. Anyway, it's fun to fly as an electric, so I'm not too concerned.
Old 05-18-2011, 01:25 PM
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Default RE: How much wind needed for slope soaring?


ORIGINAL: Mustang Fever

That's OK. Thanks for the reply. I just remembered that he was talking about having flown at a Torrey Pines in Ontario.

He designed a 50" semi scale P-51 years ago, it appeared in RCM and the plans are still available. I built one and put a small electric motor in it so I can fly it around here. (No cliffs.) Someday I'll get to try sloping it. We go to a cottage in the Mich UP every summer that's at the east end of a lake that gets strong west winds. There's about a 40 foot vertical bluff at our end, and it forms sort of a half bowl, so maybe [:-]

I've never sloped before so I'm hoping the motor will keep me out of trouble if I blow it. My only real concern is that it's too heavy- the original design built out at 2 pound, and mine is 3, with a wing loading of over 18 oz per square foot. Anyway, it's fun to fly as an electric, so I'm not too concerned.
18 oz wind loading is nothing if the the wind and slope is good. Many big wind slopers for good sights come in at over 40 oz per squar foot.



Old 05-18-2011, 04:18 PM
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Default RE: How much wind needed for slope soaring?

I was kinda hoping you would say that. I sorta wondered, because Mike had put a ballast box on the plans, and talked about how the plane got knocked around on its first flight, and then he put the box in with some weight and it flew a lot better.

I've got Eflite electric retracts on it, too. This design does not like to be hand launched in electric mode, so they are nice to have when flying "normally". APC 10x6 folding prop, too.
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