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Rough calculation, about 40 lbs at 80mph.
F = 1/2 * (air density) * (Velocity)^2 * (Area) * CL
CL = coefficient of lift, close enough to 1 for our purposes.
Area is estimated at 2.5 sq ft for the stock pop-up spoiler.
Air density used is sea level standard density.
Rough calculation, about 40 lbs at 80mph.
F = 1/2 * (air density) * (Velocity)^2 * (Area) * CL
CL = coefficient of lift, close enough to 1 for our purposes.
Area is estimated at 2.5 sq ft for the stock pop-up spoiler.
Air density used is sea level standard density.
Sailors simplify it a bit to .0034 * A* V^2 where A is in sq ft and V is in kts. We use it mostly to calculate how much mechanical advantage we need to hold a control line by hand.
How much downforce can it truly add with no under area of the wing?
Looks more like a spoiler than a wing.
I know Lexus marketing calls it a wing,and says it adds downforce and all,but look at the thing.
I can see it spoiling air at much more civilized speeds,versus speeds requred to get any downforce from such a design.
It works (what there is of it) by Newton's laws not bernoulli's. Simple force of air thrusting upward. So, yah, a spoiler. Get about the same effect as a bag of cement in the trunk at 80 mph. More of a "cool" thing than useful, especially since it pops up and down. "OOOH, lookit that".
It works (what there is of it) by Newton's laws not bernoulli's. Simple force of air thrusting upward. So, yah, a spoiler. Get about the same effect as a bag of cement in the trunk at 80 mph. More of a "cool" thing than useful, especially since it pops up and down. "OOOH, lookit that".
nah, it works by way of bernoullis law...the shape of the wing/foil affects air flow speed (and pressure zones) above and below the wing/foil thus introducing a downward force.. and plenty of high end race cars have functional wings that pop up and down. I will say in the case of the RCF I don't see it adding much downforce mainly due to its size.
nah, it works by way of bernoullis law...the shape of the wing/foil affects air flow speed (and pressure zones) above and below the wing/foil thus introducing a downward force.. and plenty of high end race cars have functional wings that pop up and down. I will say in the case of the RCF I don't see it adding much downforce mainly due to its size.
You really ought not try to explain aerodynamics to a sailor and a nuclear engineer. Bernoulli forces are not working in a "venturi" like system in air since air is compressible while water is not. Don't feel bad, though. A lot of sailors get this wrong as well. Actual lift is even more complicated since it deals with air viscosity. Here's a aerospace guy explaining it http://gentrysailing.com/pdf-magazin...eally-Work.pdf
Last edited by SailorTPD; Oct 4, 2022 at 08:04 PM.
You really ought not try to explain aerodynamics to a sailor and a nuclear engineer. Bernoulli forces are not working in a "venturi" like system in air since air is compressible while water is not. Don't feel bad, though. A lot of sailors get this wrong as well. Actual lift is even more complicated since it deals with air viscosity. Here's a aerospace guy explaining it http://gentrysailing.com/pdf-magazin...eally-Work.pdf
That maybe so, but there has been at least one TVD malfunction! You can’t say TVDs are 100% perfect! I gotcha back 07LXgs350.
You really ought not try to explain aerodynamics to a sailor and a nuclear engineer. Bernoulli forces are not working in a "venturi" like system in air since air is compressible while water is not. Don't feel bad, though. A lot of sailors get this wrong as well. Actual lift is even more complicated since it deals with air viscosity. Here's a aerospace guy explaining it http://gentrysailing.com/pdf-magazin...eally-Work.pdf
Since we are going to list our credentials, I'm a mechanical engineer working in the aviation field for 10+ years. This is directly from the your article...
"Once a complete set of streamlines is determined, we can make some very useful judgments as to how wind speed and pressure vary in the flow field about the airfoil. The relationship between speed and pressure is given by an equation called Bernoulli's equation. The Bernoulli equation shows how the pressure of the air and the speed of the air are directly tied together..."
Now this is all quite simple, but it is important to note that before we can apply Bernoulli's equation, we must first know how the air flows about the airfoil. We must know where the streamlines go. The sailing literature is full of these types of drawings. Unfortunately, they are just that, drawings of where the particular author thinks the air goes...
more articles explain how Bernoulli's law applies to airfoils:
That maybe so, but there has been at least one TVD malfunction! You can’t say TVDs are 100% perfect! I gotcha back 07LXgs350.
😂
I wouldn't tell someone that I'm a 100% sure something will never fail when there has been instances of failure/malfunction on this board. People were persuading the dude not to buy a warranty (because toyota) when there are multiple expensive items that have could fail including the dreaded valley plate leak.
Last edited by 07LXgs350; Oct 5, 2022 at 08:37 AM.
I wouldn't tell someone that I'm a 100% sure something will never fail when there has been instances of failure/malfunction on this board. People were persuading the dude not to buy a warranty (because toyota) when there are multiple expensive items that have could fail including the dreaded valley plate leak.
There are no guarantees in life but would you wear a raincoat outside if someone said there would be a 1% chance of rain?
I had a valley plate leak on my ISF....it's not so "dreaded"....lol.
But back on topic. I am intrigued by how you would calc downforce on our wings. I think I saw a video on a wind tunnel with the spoiler up and it didn't show any airflow below the wing. Of course it's just a prom video from Lexus so who knows if that was an accurate wind tunnel vid.
Is it enough to shear off a bolt when a Varis replica is swapped? I would have to say yes or could just be a one off! It broke the motor that engages the spoiler to go up and sheared a bolt. The spoiler I had when the motor broke
