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How slope soaring works

CrashRecovery

I'm a care bear...Really?
Mentor
#1
Someone please explain it to me. How does the plane stay moving with out being blown back? Like JGAF's plane, how does that thing fly like that?
 

zev

lumpy member
#2
I was just reading this article, might help: http://www.fatlion.com/sailplanes/slope.html

but basically air coming in from the ocean, (in JGAF's case) or any other big flatish place, hits the slope and is directed upwards creating lift. I guess it does get blown back, you will notice in JGAF's video he is almost always facing the ocean.
 
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#3
DAFDFD58
Think of it this way.
If air is coming up a 30 degree slop at 15mph (22ft/s) it will be rising vertically at a rate of 5.1ft/s (22xsine20 degrees).
If a glider flying at 20mph has a sink rate of 3ft/s it must climb at 2.1ft/s - provided of course it stays in the area of the rising air. ;)
 

CrashRecovery

I'm a care bear...Really?
Mentor
#4
Well I understand the idea of lift. Same idea with hang gliders. It just seems weird that the plane doesn't sit nose up or down to keep movement going. And how smoothly it moves how it rolls so elegantly. It's so cool
 
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robschonk

Senior Member
#6
Well I understand the idea of lift. Same idea with hang gliders. It just seems weird that the plane doesn't sit nose up or down to keep movement going. And how smoothly it moves how it rolls so elegantly. It's so cool
It still maintains the same angle of attack with regard to its flight path, but when the parcel of air is rising, it appears that its nose is higher.
 

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colorex

Rotor Riot!
Mentor
#7
Think of it like this maybe, the plane is losing altitude while gliding - at the same rate as the air around it is moving upwards.

Note that the plane is not horizontal, it's always tilted a few degrees down to maintain it's position. If you raise the nose, the wind will blow your plane backwards.
 

IamNabil

Senior Member
#8
The deceptive bit here is that while you think of the plane as flying above the ground, the plane only feels the air. If the air is rising more than the plane is sinking, then all the plane feels is lift. Just like if you are flying at 20 mph, and a ten mph head wind comes on, you will have 10 mph of ground speed, but still 20 mph of air speed. :D You have to imagine the plane as though it is moving in a moving body of air, not just watch its position over the ground.