JHZR2
Staff member
Hoping for some opinions from those so inclined.
Have a Cover Logic Monarc carport for the summer. Just to keep some direct sun off of cars in the pm sun.
Set it up and of course we had a windy day (25-45 mph gusts), and it lifted up and dropped. My child observed it, and said it flew up towards the clouds, flipped and dropped back down. Good thing nobody and nothing was out there!
It will be on asphalt, which is why I hadn't tied it down yet. I don't think tapcons are right for asphalt.
So... lift. I know it's somewhat straightforward, but can also be rather complex in terms of lift coefficient.
So what Id like to calculate is how much weight, and how strong of cord, I'd need to use in addition to some sort of anchors, to keep this thing from flying up and away.
I'm thinking that wind in approximation is horizontal flow, and if normal to the arc of the canopy, I guess induces lift (though it's hollow and so doesn't really have a different length/distance on top and bottom) as is necessary.
I was going to go along the route of this:
https://wright.nasa.gov/airplane/lifteq.html
With the simplified assumption of CI as:
Cl = 2 * pi * angle (in radians)
Am I overthinking this? Is there a simpler/better way?
Perhaps just an angle derating of the wind pressure calculation P = 0.00256 x V2, where V is the speed of the wind in miles per hour (mph)?
The unit for wind pressure is pounds per square foot (psf)... Thinking then I just calculate times the tarp area, and then * sin(assumes incident angle of wind)?
Thanks!
Stock image from Home Depot:
Have a Cover Logic Monarc carport for the summer. Just to keep some direct sun off of cars in the pm sun.
Set it up and of course we had a windy day (25-45 mph gusts), and it lifted up and dropped. My child observed it, and said it flew up towards the clouds, flipped and dropped back down. Good thing nobody and nothing was out there!
It will be on asphalt, which is why I hadn't tied it down yet. I don't think tapcons are right for asphalt.
So... lift. I know it's somewhat straightforward, but can also be rather complex in terms of lift coefficient.
So what Id like to calculate is how much weight, and how strong of cord, I'd need to use in addition to some sort of anchors, to keep this thing from flying up and away.
I'm thinking that wind in approximation is horizontal flow, and if normal to the arc of the canopy, I guess induces lift (though it's hollow and so doesn't really have a different length/distance on top and bottom) as is necessary.
I was going to go along the route of this:
https://wright.nasa.gov/airplane/lifteq.html
With the simplified assumption of CI as:
Cl = 2 * pi * angle (in radians)
Am I overthinking this? Is there a simpler/better way?
Perhaps just an angle derating of the wind pressure calculation P = 0.00256 x V2, where V is the speed of the wind in miles per hour (mph)?
The unit for wind pressure is pounds per square foot (psf)... Thinking then I just calculate times the tarp area, and then * sin(assumes incident angle of wind)?
Thanks!
Stock image from Home Depot: