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Consider a formula 1 car that is travelling at 150mph.
Now -- a computer knows when the car needs to slow down quickly - easy stuff. At this point a small vent opens in the front of the car .. air rushes into to a temporary storage area where, due to the current speed of the car, it is compressed.
When
maximum pressure is achieved, which will be relatively quickly, the vent closes. So it may only be open for 1 second for example. The pressurised air is in the enclosed compartment in the car, and if anything the car has slowed down faster than it would have otherwise.
Now -- when the computer senses the racing driver accelerating again (after the corner) .. at the BACK of the car another vent opens releasing the air through a smallish nozzle. The pressure difference makes the air fly out of the back, acting as an additional propellant (boost) for the car.
The car's early acceleration is therefore faster.
Dispelling the Myth about "Ram Air" in Automobiles
http://www.vetteguru.com/ramair/
[Globi]'s first link as a link. [phoenix, Oct 05 2004, last modified Oct 17 2004]
Ram Air, Hot Air
http://www.snowgoer.../tech_ram_air.shtml
[Globi]'s second link, fixed and as a link. [phoenix, Oct 05 2004, last modified Oct 17 2004]
ferrari F1 aerodynamics
http://www.sportnet...ain/s85/st21681.htm
[engineer1, Oct 05 2004, last modified Oct 17 2004]
RAM AIR: What's It Worth?
http://www.sportrid.../tech/146_9508_ram/
[Globi]'s third link as a link. [bristolz, Oct 05 2004, last modified Oct 17 2004]
air scoop picture
http://www.californ...e/70_Tice_c155.html
facing backwards [engineer1, Oct 05 2004, last modified Oct 17 2004]
airscoop again
http://specificatio...d.com/6pak6bbl.html
facing forward. [engineer1, Oct 05 2004, last modified Oct 17 2004]
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I recently saw a documentary on F1 racecar design the front end is designed to very stict safety criteria, in that it must absorb frontal damage very well cushioning the driver in the event of a head on collision with a solid wall for example but must also break apart enough not to spear through another car in the event of a T bone crash. |
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How much Thrust would this air pressure jet provide, would it have any effect given the aerodynamics of racecars? |
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What you're thinking of is basically capturing RAM pressure. However that pressure is neglectable below Mach 0.5. So you can't really capture any pressurized air from airstream. |
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You can use it as an airbrake though, which is prohibited in F1 however. |
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Firstly this movable flap could be somewhere else but the nosecone of the car .. perhaps down the side of it. It only opens when the car wants to slow down so I see it worsening the aerodynamics of the car, on purpose, when it is open. |
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When the car is starting to accelerate again it is back in 100% aero-dynamic mode. The air being spewed out of the back -- I see it as being a relatively small part of the car's overall power. |
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Perhaps from the speeds 20 mph to 60 mph it may add 5% power to the car. I see the nozzle at the back of the car (that only opens when the car wants to accelerate) as being maybe 1 inch in diameter .. so the air will fly out of there at a fair old rate to aid the car. |
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by how would it effect the aerodynamics i mean given the aerodynamics of a current F1 car would a jet of air behind it actually make a difference. |
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If your claimed 5% happened i suspect the handling during acceleration would also suffer, but that's just a gut feeling after all the driving wheels are spinning to give one acceleration that is lower than the actual acceleration. |
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And finally for this anno any container that is capable of holding pressure is going to add weight. |
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also I'm pretty sure any form of 'jet' propulsion isn't allowed in F1. Goes for rockets..and.. well.. rubber bands too. |
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Dashit -- there goes my rubber band idea. |
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I'm not even going to try the 'stand on rollerskates and light a huge rocket on your back' idea!! |
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Without bothering to do any calculations at all, I suspect the 5% figure is massively optimistic. The vent at the front may well slow the car down a few percent quicker, but as far as forward acceleration goes you're probably out by a factor of 1,000,000 or so. |
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Try this:
1. Attach a funnel to a toy balloon. Hold it out of the window and see how fast you have to drive to inflate the balloon (don't kill yourself trying).
2. Turn the (fully inflated) balloon/funnel around and release the air. Feel the thrill of 1-balloon-power acceleration. |
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Quite apart from any technical considerations, F1 regulation forbid the use of moveable aerodynamic elements. |
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Here's a simple test, if you don't believe physics and the RAM point.
Take a balloon and try to fill it using a funnel while driving on a highway (you should sit on the passenger seat.) You will have a really hard time to fill this balloon eventhough your lungs are obviously capable to. By the way, the same lungs that can't even pump up a simple air mattress.
Oh, I just noticed benjamin already made that point. |
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PS: The time will come when software packages will tell us that 2+2 is 5 and everybody will believe it, since the guy that came up with it had a MBA. |
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(-) bad science. At 150 mph, captured ram air pressure will give you much less benefit than the added weight of the mechanism will cost. |
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RAM is not that bad though. Otherwise F1 cars wouldn't actually use it to feed their engines. The extra pressure leads to more oxygen to burn, which in turn increases the power of the engine slightly at top speeds. (It's rather a chemical benefit than a physical). |
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But it wouldn't effective in this application. |
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[Globi]: F1 cars do not use ram pressure; their airboxes must be designed such that there is minimal ram effect. |
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[Globi]: Please use the links function to add links as citations rather than embedding them in your annotations. They tend to break the page layout. |
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angel, F1 cars ARE using RAM pressure. The opening of the airbox is clearly facing the incoming air. This opening not only increases the aerodynamic resistance of the car but also obstructs the air flow to the rear wing. So why are they doing it?
If the F1 designers wouldn't want RAM pressure they would locate the airbox opening facing the sky or facing the side of the cars which would reduce the aerodynamic resistance of the car as well as improving the flow to the rear wing.
By the way this was indeed the case in the turbo era. |
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Anyway, at top speeds (200mph) RAM pressure is maybe 5% higher than static pressure. Why would a F1 designer be so silly and not harvest it? |
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Weight. They want light cars. I doubt that the small boost from the compressed air would compensate for the increased weight of all the parts required to get the force from the pressure to the wheels on the rest of the track. Could the power make up for even 1 lb of extra material? |
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I think regenerative braking is the way to go. But, the governing bodies of car racing have very strick limits on what modifications can be done on the car. If it was a free-for-all, do you think all the cars would look almost exactly the same ;) |
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The cars have to weigh 600kg including driver. The empty cars weigh less than 500kg and they mount additional weight to get to the required weight. If they can have 40HP almost free power for 0.5kg more weight, they'll definitely take it (which really only means that they have to mount less extra weight).
But next Sunday watch the F1 Grand Prix in Montreal and have a closer look at the airbox, you'll see. |
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But I agree, regenerative braking would have been the way to go, but they prohibited it some time ago, because it would have made the cars much more complex than they already are. It's a missed opportunity for the F1 to actually contribute something more useful to the rest of the world.
(But who cares the sun will explode at some point anyway.) |
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If everything would be allowed, the cars would probably run on gas turbines (more power per weight) and store braking energy in flywheels or air tanks (more energy content per weight than batteries). Each brake would be individually controlled. They would use fans to suck the cars to the ground at low speed. The wings would adjust according to the speed and the cars would run 300mph. The gearbox would be a CVT, the engines would always run at the same rpm. They would use active suspension. The cars would have 4 wheel drive and 4 wheel steering or even 6 wheel drive and 6 wheel steering. Each wheel's steering angle would be separately controlled. The cars would use active differentials, so outside wheels can spin faster than inside wheels and therefore accelerate the yaw speed. The cars would use an accurate positioning system, so they could always predict the next turn and bump. The pilots would need to wear pressurized suits to cope with the incredible G-Forces. At some point the cars would completly control themselves and only have to make sure that the pilot survives 'til the end of the race. After all someone has to shake that bottle, but maybe cars could be taught to do this too. But who's going to the interview? |
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[Globi] - // If the F1 designers wouldn't want RAM pressure they would locate the airbox opening facing the sky // |
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If they did that, the bernoulli effect would try to suck the air out of the intake. |
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It depends where you locate it, the car has positive and negative pressure points over the whole shape.
But I agree having the intakes on the side would probably be safer, if someone for whatever reason wanted to avoid that vicious RAM pressure. |
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Has indeed no-one ever noticed that hole above the helmet and questioned what it might be good for? Where's the problem? No TV's at home? |
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Globi has a good idea. Allow everything. We can have cars that take corners at 300mph. :) The only downside is the danger to the drivers. But there is a solution to that. Put the cockpit in the garage. Drivers drive their cars by remote control. Cameras on the cars beam back pictures which are then shown on the walls of the cockpit. No more deaths and broken bones in F1. :) |
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I consider motor racing to be a sport as it's physically demanding. Remote controlled F1 might lose its sportishness. |
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Globi, a lot of aerodynamics is counterintuitive look at air scoops mounted in bonnets/hoods of cars some face forward some face backwards. It all depends on the desired effect and local airflow which an be affected by both features ahead and behind the scoop. |
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All the things I mentioned are not my ideas.
Most of these ideas were realized. (For example Lotus developed a gas turbine race car over 30 years ago). |
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Basically you just have to read the F1 regulations and than you know what is feasible. It's the engineer that came up with the idea and the lawyer that came up with the regulation thereafter (and backed by a bunch of dead race car drivers). |
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I think watching robot cars driving in circles would be fun too. Especially if they were allowed to be more aggressive.
Actually all that circus around F1 and Hollywood is pathetic and robot cars as well as virtual actors might get rid of it. They can't go at any events. They can't cheat on each other. They don't need private jets and mansions. All the focus is back on the real cause. And maybe the creative engineers might receive some credit for once too. |
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Use robots and a lot of car safety research and inovation doesn't happen |
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The robots do not innovate. They are the result of innovation. |
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I thought cars were driven using "feel" as well as "vision". That's why I can't get a high score on the Playstation (My excuse). |
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Actually, in conjunction with the windshield's redirecting resistance, reverse-scoops allow cold air to be introduced into intake without mixing with hot air under the hood, as would be the case with forward scoops. |
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I agree with Zanzibars comment on average cars. |
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Reverse scoops on racecars usually increase the flow through the watercooler (and oil cooler):
A race car's engine might have an efficiency of 20%. So if a race car generates 500HP, it also generates 2500HP heat that the cooler needs to get rid of. Which either can be solved with a giant cooler or increasing the airflow through the cooler. |
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Forward scoops collect RAM pressure and reduce air friction to the airbox/intakes. (Which in comparison can be significantly smaller, there's no point to feed the engine more than it can digest).
(The Pontiac's 'RAM holes' are far too big and probably were designed like this for marketing reasons only.) |
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not bad. Could use a re-enforced mesh to capture the air and maybe a small nozzle shaped like a space shuttle nozzle which is open all the time. or maybe 2-1 for each side. |
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the drag created by scooping and storing the compressed air destroys any gain you might experience from releasing it |
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Dude the whole point is that the vents used to capture the air provide braking when the car needs it and that is when they capture the air. Consider reading ideas fully before critisizing them (and having a few of your own wouldn't hurt before you share your concerns about others'). |
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Now, now, [acurafan07]. The lad just got here. You're supposed to welcome him to the Halfbakery, tell him where the help file is, and THEN jump all over him with both feet. |
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I'd like to consider myself the resident F1 expert, although I may be not. |
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The ram air effect was put to massive use in the late 70's when the airboxe openings were almost 2 feet tall. |
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Bernie Eccelston (F1 Supremo) didn't like the top heavy look of the cars and changed the regulations. |
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What about the equal and opposite reaction of slowing the car while filling the swhoosh bladder thingy? |
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