Thread Tools
Oct 17, 2019, 01:22 PM
Registered User
Thread OP
Discussion

How much wind is needed?


I believe I may have found a mountaintop soaring site. A NW wind is unobstructed for 10 miles or more. So being totally inexperienced in this, how much wind speed is needed for say a lightweight 16 oz 2m plane? A 45 oz 3m? A 65-70 oz full house composite?
Sign up now
to remove ads between posts
Oct 17, 2019, 02:00 PM
High Lift Coefficient
Sailhigh's Avatar
I don't think there are hard rules for this. I never measure the wind velocity. I just take the airplane to the lip of slope, face the wind and see if the model really wants to leave my hand. If so, I throw her straight out, turn parallel to the slope and see how she performs. If she keeps on climbing, I let her push out and away from the slope. If not, turn back and land and wait for the wind to pick up.
Oct 17, 2019, 02:03 PM
Yes, ALL your money...
winchdoc's Avatar
As you might suppose, there are other features that figure into what makes a good hill.
How tall is the slope? More points for high slope.
How steep is it? More points the more vertical.
Unobstructed for 10 miles, you say? Extra points there, too.
Also, is it possible to get thermal lift as well?
All this makes a wind speed bracket kind of ambiguous.
<5mph you’ll want some thermal help...
>15mph should be enough for a 3m F3X on a good hill.
There’s an old saying,”There’s always enough lift for other people’s planes. “
Oct 17, 2019, 03:50 PM
DS Junkie
Screamin' Eagle's Avatar
The first two planes you described are light enough to be thermalled out on a flat field -- maybe even from a hand launch -- so my answer is ZERO wind!!
Oct 17, 2019, 04:17 PM
Registered User
Thread OP
Quote:
Originally Posted by winchdoc
As you might suppose, there are other features that figure into what makes a good hill.
How tall is the slope? More points for high slope.
How steep is it? More points the more vertical.
Unobstructed for 10 miles, you say? Extra points there, too.
Also, is it possible to get thermal lift as well?
All this makes a wind speed bracket kind of ambiguous.
<5mph you’ll want some thermal help...
>15mph should be enough for a 3m F3X on a good hill.
There’s an old saying,”There’s always enough lift for other people’s planes. “
Quote:
Originally Posted by Screamin' Eagle
The first two planes you described are light enough to be thermalled out on a flat field -- maybe even from a hand launch -- so my answer is ZERO wind!!
Well yeah. So can the third plane. Just interested in “expanding my horizons”.

This spot rises over 1000’ from surrounding valley floors. The closest hills are maybe a couple hundred feet lower.
Thanks all for the help. I guess I’ll just have to schlep the plane up the hill dependent upon wind speed. Luckily there is a weather station up there with available and constantly update data online.

Name: 509B4537-5AB0-4846-8F6D-A476FC8A20F6.jpeg
Views: 51
Size: 3.52 MB
Description: Looking NW
Oct 17, 2019, 05:03 PM
Registered User
How much wind is needed?

I hate to be "that guy", but the answer is, "The amount that generates lift for your plane."

I had some 8 mph winds on Sunday when I sloped for the first time blowing into the cliff I was standing on, and it generated plenty of lift for us to keep flying our gliders for 10 minutes at a time - and we only stopped because our bodies were getting tired of standing!

Out at my club's field, I've flown gliders in non-existent, gentle, 2 mph winds, getting lift and allowing me to keep the plane climbing from a combination of thermals and nosing into some slight dives for speed, or very little prop thrust, simply because I would pick up some upcurrents of air.

It's honestly a lot of factors to figure out, and what speeds might be great at one location might be absolutely horrid at another location...sometimes, you pull out your plane, and before you throw it, you know by how it's pulling in your hand. Does that help?
Oct 17, 2019, 06:38 PM
Registered User
tomleach's Avatar
And while the hill may be unobstructed by other hills, if those trees at the lip are as close as I think, it may be pretty turbulent, especially when launching/landing.
What i would recommend is to get an Alula, Weasel, light combat wing, something EPPish and bouncy and chuck it first. Alula's are nice because you can side-arm launch them to a decent height, they bounce, and they're cheap.
There is a slope near me that is fairly similar (Mary's Peak at the saddle for Doc) that looks similar, maybe a bit more drop off before the trees. I've tried it -once-. The turbulence flipped me over so fast it was scary (I was using a big crunchy as my test ship back then).
I do want to go back and try it again some time, but I have other better (but farther away) slopes so I just haven't.

If the landing area is similar to what's in front, you may want to stay away from glass ships and go for more foam, at least until you can hand catch.
Good luck, report back if you can.
Oct 17, 2019, 06:39 PM
Just Toss It !!!
MATIN's Avatar
The "hill" looks fine......But those trees in the foreground might be a deal breaker.
Oct 17, 2019, 07:13 PM
Registered User
chip.greely's Avatar
Hmmmm,

Where's the Lift?
Oct 17, 2019, 08:55 PM
Registered User
Thread OP
Quote:
Originally Posted by sprzout
How much wind is needed?

I hate to be "that guy", but the answer is, "The amount that generates lift for your plane."

I had some 8 mph winds on Sunday when I sloped for the first time blowing into the cliff I was standing on, and it generated plenty of lift for us to keep flying our gliders for 10 minutes at a time - and we only stopped because our bodies were getting tired of standing!

Out at my club's field, I've flown gliders in non-existent, gentle, 2 mph winds, getting lift and allowing me to keep the plane climbing from a combination of thermals and nosing into some slight dives for speed, or very little prop thrust, simply because I would pick up some upcurrents of air.

It's honestly a lot of factors to figure out, and what speeds might be great at one location might be absolutely horrid at another location...sometimes, you pull out your plane, and before you throw it, you know by how it's pulling in your hand. Does that help?
Yeah I know. I guess I was going for a ball park of like, "Well a 65 oz F3J type composite may do well in 10 mph or may require 15-20 but forget it under 10. I realize there is no clear answer and probably will simply take experimenting at that site. Just I was trying to avoid backpacking a plane one mile uphill with a 10 mph wind if it will require 20 mph for it to fly...type of thing. And yes, the tip at the end does help, thank you.

Quote:
Originally Posted by tomleach
And while the hill may be unobstructed by other hills, if those trees at the lip are as close as I think, it may be pretty turbulent, especially when launching/landing.
What i would recommend is to get an Alula, Weasel, light combat wing, something EPPish and bouncy and chuck it first. Alula's are nice because you can side-arm launch them to a decent height, they bounce, and they're cheap.
There is a slope near me that is fairly similar (Mary's Peak at the saddle for Doc) that looks similar, maybe a bit more drop off before the trees. I've tried it -once-. The turbulence flipped me over so fast it was scary (I was using a big crunchy as my test ship back then).
I do want to go back and try it again some time, but I have other better (but farther away) slopes so I just haven't.

If the landing area is similar to what's in front, you may want to stay away from glass ships and go for more foam, at least until you can hand catch.
Good luck, report back if you can.

Quote:
Originally Posted by MATIN
The "hill" looks fine......But those trees in the foreground might be a deal breaker.
The trees are a concern as I have one flat field site with a treeline where I thermal fly. If the wind is from the south, forget it. The turbulence is unbelievable below about 100', especially with a light plane. But the picture doesn't quite capture the terrain. That is a partial panoramic shot, and the trees to the left are directly west. West or East wind won't work at this site. But NW or NNW and it drops a bit more dramatically that the picture seems to indicate. Is it enough to eliminate ground level turbulence? Only one way to know. I thought best bet may be to take a foam Radian up there first before flying my built-ups or composites.
And yes the rocky ground is a concern, luckily behind is better than what you see in front. At least there are larger patches of rock free ground.

Amazing living in the mountains and such lack of soaring sites but most of the issues are just this. My very limited attempts have proven even IF you can find a non-forested open hilltop, usually there are too many surrounding hills, buildings, or treelines and turbulence is severe.

Thanks for the helpful replies.
Oct 18, 2019, 12:43 AM
new to the sport
maybe give it a try and report back!
Last edited by bracesport; Oct 18, 2019 at 03:12 AM.
Oct 18, 2019, 04:04 PM
Fully Sending It
Xpress..'s Avatar
Chuck it off and see what happens.

Disclaimer, I usually do this with my EasyGlider 4. It flies on almost nothing, and when nothing runs out I can bail out with the motor
Oct 18, 2019, 05:06 PM
Formerly known as Konajoe
Do birds of prey soar there? (Hawks, Kestrels, Vultures, etc.) and are they riding thermals or slope lift? Watching these birds will tell you a lot about what the wind is doing - how smooth or turbulent the air is, how strong the lift is, and how big & where the lift zone is. Once you've found a slope where these birds are doing their thing well, all that you would need to answer is whether the landing area is adequate for whatever plane you are flying. Fly a plane that is pretty crash resistant like a combat wing or other foamy and get used to the slope and especially the landing approach before throwing out high-dollar crunchies. Every slope is unique and will require a different approach to flying there from one to the next.
Last edited by JPEvans; Oct 18, 2019 at 05:15 PM.
Oct 18, 2019, 08:02 PM
Registered User
Thread OP
Yeah I think to start my old beat up Radian would be the choice. I'll have to blow the dust off it and haul it up there and see what we have.


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Poll How much wind is too much. FloridaFlyBob Electric Plane Talk 16 Nov 29, 2016 05:55 PM
Question How much wind, Hobby King mini DLG zekjet Hand Launch 1 Jun 29, 2016 08:49 PM
Discussion How much wind dose it require for soarer plane? renyizhang Sailplane Talk 11 May 11, 2016 02:06 AM
Discussion How much wind...? CGAR Hand Launch 7 Dec 12, 2015 07:33 PM
How can you tell wind speed/ How much wind is too mucH? ssyed Beginner Training Area (Aircraft-Electric) 15 Aug 02, 2004 11:04 PM