Coming Soon: Canards
10-18-2008, 01:38 AM
#76
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and agree on the 
10-18-2008, 05:53 PM
#77
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10-18-2008, 07:28 PM
#78
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10-19-2008, 12:17 AM
#79
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Some of that issue is due to NASCAR's stupid height requirements at tech. The splitter is supposed to be something like 3 or 4 inches off the ground when they have the templates out. Then when the cars are running, the suspension is such to allow the car to run on its bump stops and get the splitter down to where it does some good. It's a ludicrous situation that the engineers are trying to work around.
10-19-2008, 03:20 AM
#80
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10-19-2008, 02:20 PM
#81
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475hp/460lb.ft
10-19-2008, 02:58 PM
#83
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10-19-2008, 03:31 PM
#84
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Well, no matter on the quote that doesn't exist. No matter, either way, Jim is incorrect. So, let's begin shall we?
"Doc last time I checked airplanes were NOT trying to create downforce"
An airplane wing does produce lift. Here's a field experiment for evereyone. Find and visit your nearest community airport, and first ask for a demo or intro flight(cause we need more pilots). Next, find any low wing plane and have a look at the wing from end-on. Nice and flat on the bottom, and well rounded on the top. Good for generating lift, as Jim mentioned. The forces at work on an aircraft are lift, gravity, thrust, and drag. When all these are in equilibrium, we have level, unaccelerated flight. The plane is held up against gravity by the lift of the wing and the horizontal stabilizer. But wait, go back and look at the horizontal stabilizer end-on.
What's this? It's symmetrical about the chord line. How can that be, if it's supposed to be a lifting surface. Well, is it supposed to lift? That depends. The horizontal stabilizers job is to provide a pitch change to the plane. also, to stabilize the plane in the pitch axis. We'll load our hypothetical Cherokee with two in front, two in back, and a bit of baggage. The center of gravity is well behind the center of pressure on the main wing. As we fly along in level flight part of the lift is generated by the horizontal stabilizer. Same plane, we take out the rear seat pax, and the baggage. What now, we have the center of gravity forward of the center of pressure on the wing. Well, that's gonna cause the nose to go down, plus the added torque of the thrust line being about 9 inches above the center of drag. All this is going to make the plane want to pitch down. How do we fix that problem?
Downforce. The horizontal stabilizer is actually not producing lift in this configuration but is actually producing counter-lift or downforce. The loading graph of any airplane is kind of centered around the center of gravity point. When you load forward, you need to counteract the pitch down moment created by the forward load, and the thrust of the engine. This is always done with downforce.
Next, suppose we want to climb from straight and level. We want to create more lift, but have no canard on the Cherokee, so we increase the downforce on the tail to do the same job. coming in for a landing and want to make a smooth one? You need downforce on the tail to lift the nose, and make a nice flare. How about turning? Well, can't turn the plane without downforce.
So, in summary, if you fly, you need downforce. Without it, no plane will ever get off the ground(except a canard configuration aircraft). This holds true for Cherokees, Cessnas, Boeings, Douglass, etc. They all have to have downforce.
"Doc last time I checked airplanes were NOT trying to create downforce"
An airplane wing does produce lift. Here's a field experiment for evereyone. Find and visit your nearest community airport, and first ask for a demo or intro flight(cause we need more pilots). Next, find any low wing plane and have a look at the wing from end-on. Nice and flat on the bottom, and well rounded on the top. Good for generating lift, as Jim mentioned. The forces at work on an aircraft are lift, gravity, thrust, and drag. When all these are in equilibrium, we have level, unaccelerated flight. The plane is held up against gravity by the lift of the wing and the horizontal stabilizer. But wait, go back and look at the horizontal stabilizer end-on.
What's this? It's symmetrical about the chord line. How can that be, if it's supposed to be a lifting surface. Well, is it supposed to lift? That depends. The horizontal stabilizers job is to provide a pitch change to the plane. also, to stabilize the plane in the pitch axis. We'll load our hypothetical Cherokee with two in front, two in back, and a bit of baggage. The center of gravity is well behind the center of pressure on the main wing. As we fly along in level flight part of the lift is generated by the horizontal stabilizer. Same plane, we take out the rear seat pax, and the baggage. What now, we have the center of gravity forward of the center of pressure on the wing. Well, that's gonna cause the nose to go down, plus the added torque of the thrust line being about 9 inches above the center of drag. All this is going to make the plane want to pitch down. How do we fix that problem?
Downforce. The horizontal stabilizer is actually not producing lift in this configuration but is actually producing counter-lift or downforce. The loading graph of any airplane is kind of centered around the center of gravity point. When you load forward, you need to counteract the pitch down moment created by the forward load, and the thrust of the engine. This is always done with downforce.
Next, suppose we want to climb from straight and level. We want to create more lift, but have no canard on the Cherokee, so we increase the downforce on the tail to do the same job. coming in for a landing and want to make a smooth one? You need downforce on the tail to lift the nose, and make a nice flare. How about turning? Well, can't turn the plane without downforce.
So, in summary, if you fly, you need downforce. Without it, no plane will ever get off the ground(except a canard configuration aircraft). This holds true for Cherokees, Cessnas, Boeings, Douglass, etc. They all have to have downforce.
10-19-2008, 03:34 PM
#85
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10-19-2008, 04:20 PM
#86
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I will say that when I used to fly my Quicksilver Ultralight in Texas too late on a given summer morning, and the updrafts were kicking in, I sure prayed for downforce a lot!
10-19-2008, 07:45 PM
#87
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true, except when turned upside down.......which is the case on most race cars.
no disrespect to the engineers intended.
--Russ
10-19-2008, 07:56 PM
#88
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Several models that come to mind: Citabria 7ECA, 7KCAB, Beech C23A, F33C, and the whole range of experimental planes.
Best leave engineering to engineers.
10-19-2008, 08:35 PM
#89
Nordschleife Master
uh oh, not that Russ again.......talking about things he doesn't understand?
Thought we decided to stick to Big rigs and Mopars (but on other boards please)....... what happened dude?
Also, when are you going to get some color on that poor car?
My dads a pilot and ive spent my fare share of time at the airports and fooling with his plane, but i dont now enough about aircraft to comment on them.
Thought we decided to stick to Big rigs and Mopars (but on other boards please)....... what happened dude?
Also, when are you going to get some color on that poor car?
My dads a pilot and ive spent my fare share of time at the airports and fooling with his plane, but i dont now enough about aircraft to comment on them.
