Sorry for my spelling I'm just not that good at it but here it goes.
If you are flying flat out in a US leagle ultra light up wind into a 60mph wind you will be just about standing still. Now if you turn down wind, after you turn though 180 deg. you will be going about 120mph over the ground. Now it you hit an air body that isn't moving relative to the ground you will now be going 120 mph indacated air speed. Your wings may just snap off if you fly twice the red line speed of an airplane. It is hard to visualize where the power to snap your wings off comes from. So we as human beings tend to be afrade of what we don't understand particularly if it is powerful.
How powerful?
Here is an example. How fast will an airplane with an 8:1 L/D @ 400mph fly if you turn down wind in a 30 ft/sec. wind and then up wind in a 0 ft/sec. wind every 15sec.? With am L/D of 8:1 you will louse 4ft/sec/sec. Or 240 ft/sec/min.
What you will be doing is repeatedly crossing and then recrossing a wind shear. If you are flying in the direction opasit to the wind in the still air then pull up acrost the windshear into the wind your indacated air speed will go up by the wind speed. Your ground speed will be the same. You then tern though 180 deg. and cross the wind shear in the opasit direction. Your ground speed was hire than you air speed by the amount of the wind speed. When you enter the still air you airspeed and ground speed mach. In one trancition from still air to where the wind is blowing and back you have added twice the wind speed to your air craft. With a 30 ft/sec wind speed you have added 60 ft/sec to your air speed. Do that 4 times per min. and you will add as much air speed as an aircraft with an 8:1 L/D will lose in one min. at 400 mph.
If you had a valley that ran at a right angle to the wind and was deep enogh for you to pull into and out of and you had a P-51 you could push the P-51 400 mph with a 21mph (30ft/sec.) wind. It's called dynamic soaring.
If you are flying flat out in a US leagle ultra light up wind into a 60mph wind you will be just about standing still. Now if you turn down wind, after you turn though 180 deg. you will be going about 120mph over the ground. Now it you hit an air body that isn't moving relative to the ground you will now be going 120 mph indacated air speed. Your wings may just snap off if you fly twice the red line speed of an airplane. It is hard to visualize where the power to snap your wings off comes from. So we as human beings tend to be afrade of what we don't understand particularly if it is powerful.
How powerful?
Here is an example. How fast will an airplane with an 8:1 L/D @ 400mph fly if you turn down wind in a 30 ft/sec. wind and then up wind in a 0 ft/sec. wind every 15sec.? With am L/D of 8:1 you will louse 4ft/sec/sec. Or 240 ft/sec/min.
What you will be doing is repeatedly crossing and then recrossing a wind shear. If you are flying in the direction opasit to the wind in the still air then pull up acrost the windshear into the wind your indacated air speed will go up by the wind speed. Your ground speed will be the same. You then tern though 180 deg. and cross the wind shear in the opasit direction. Your ground speed was hire than you air speed by the amount of the wind speed. When you enter the still air you airspeed and ground speed mach. In one trancition from still air to where the wind is blowing and back you have added twice the wind speed to your air craft. With a 30 ft/sec wind speed you have added 60 ft/sec to your air speed. Do that 4 times per min. and you will add as much air speed as an aircraft with an 8:1 L/D will lose in one min. at 400 mph.
If you had a valley that ran at a right angle to the wind and was deep enogh for you to pull into and out of and you had a P-51 you could push the P-51 400 mph with a 21mph (30ft/sec.) wind. It's called dynamic soaring.