my coanda thrusters mod :)
 

i did this a couple of days ago,
realy fast and easy, i used an empty botle of mouthwash split in half attached with tape to the back wheels' cover

the idea is that the wheel is spraying a jet of air upwords that will hit the coanda device and provide thrust (forward)

now i'm not expecting much at all, any significant amount of thrust will rip the tape of for sure, but up to 5 lb of thrust maybe possible....who knows

i havent got to highway speeds yet, just 55 mph top speed so far .
cant really tell somthing's there to it....will see

somebody needs to read up on Bernoulli's Principle, i smell unicorn poop.

The coanda effect is real. It can be displayed by placing a spoon into a vertical stream of water flowing downward, with the convex surface of the spoon facing down, as well. The spoon crates an example of coanda effect, displayed as adhesion. The water will briefly follow the curve of the spoon before continuing down. A spray with enough energy can actually temporarily reverse direction and travel up the curve of the spoon, against gravity.

How this would effect thrust on the car, I have no clue.

the problem is that thrust doesn't just appear out of nowhere, if you make a veturi the air will travel out the nozzle faster than it enters, but it's due to the pressure difference, and the thrust created out the back is nowhere near the drag created in the front.

i understand that fluid dynamics is very broad, but the spoon demonstration is hydrodynamics not aerodynamics, the flow of water is completely separate from surrounding air, that is more of a demonstration of surface tension.

so you want to take the air hitting the inside of the fender (creating drag, as the fender works as a king of parachute) and divert it out of the wheel well (effectively increasing the wake of the car) i'll jest restate beroulli's principle here, the greater the difference in pressure the greater the velocity.

i'm not questioning that the effect can exist in this situation, i'm simply stating that you won't see any benefits from any kind of thrust due to the drag from the high pressure area offsetting any thrust created

who said anything about diversion?
in fact with this set -up the air will have the tendency to stick more to the curved surface(of the coanda thing) ,thus creating less diversion to the ouside of the fender....double gain :)

so it's sticking to the coanda thingy and going where? under the car? into the car? the side of the car?

There are all kinds of thrust vectors on various parts of a object moving through the air. The sum of them is usually expressed in drag, lift and yaw (and sometimes downforce) So what you are doing here is focusing on a small area to try to create a favourable vector out of an unfavourable one.

Drag reduction is usually expressed in the reduction of the rearward drag vector. Thinking about it in the other terms is an interesting idea. Does it apply to your mod? If there is actually a favourable thust vector and it outweighs the other changes in the airflow and the changes in other vectors then, yes.

Interesting way of looking at the problem. Almost impossible to verify without some sort of testing.

The idea appears to essentially have rounded the hard edge at the bottom of the inner fender, which will help keep flow attached and going under the bumper, rather than out the sides. Since the flow haas better attachment, the issue in front of the square edge is lowered, making for what would appear to be thrust. In reality, its just less negative forces, and probably by a negligible amount. Wheel skirts would probably compliment the mod.

i don't think it will give any thrust at all, i believe it will just reduce drag based on the favorable vectors as mentioned above. much like rounding the rear part of the front fender as mentioned in the 65+ modifications list.

I a mannerof speaking, the only way to remove from one is to give to the other, and vice versa... In other words, if you are reducing drag in one vector, you're increasing thrust in the opposite vector. It's still net negative. Semantics.

Its like saying that his heater doesn't heat, rather it makes his local environment less cold. You see?

yeah, the same way deceleration is actually acceleration in the opposite direction. it isn't really the same thing but has the same effect

How about using Coanda effect as part of the undertray, to exit at the rear of the car and generate downforce while hopefully reducing wake drag?

Or, combine or utilize Coanda effect to extract cooling air from the engine bay, to vent along the sides of the car?

I'm just wondering here, without much forethought.

I've tried it with pressurized air at work - it still works when you use air instead of water.

higher speed = lower pressure. the air is basically trying to take the spoon with it (entrain it)

Great discussion, I did a wikipedia search Coanda, Did not know about his flying machine. 1910, the world's first jet aircraft.

http://www.youtube.com/watch?v=MDaUbsWNXvI


Seems like this might work if you can limit the drag from wheel well airflow beside the car.

video
 

the upper camber of the body accelerates the flow,hence dropping the pressure there in compliance with Bernouli's Theorem.The atmospheric pressure under the structure pushes the structure upwards in an attempt to reach equilibrium pressure but cannot penetrate the impermiable membrane so it remains there until power is pulled,pressure equalizes and lift goes to zero.
There is no accounting for the external horsepower necessary to created this effect.

1st jet
 

Neither of Coanda's aircraft ever made it off the ground.

coanda carb
 

can't let this free energy awesomeness go underutilized :)

http://ecomodder.com/forum/attachmen...1&d=1302036837

The spoon thing happens because the spoon redirects the water flow.

Nice vid. Expensive Coanda demo.

http://www.youtube.com/watch?v=gChp0Cy33eY

Lol, $300 table fan. Certainly no mention of efficiency in any of the glossies either or noise :)

That's the whole point of the coanda effect ...

The flow over a curved surface will redirect the flow and exert a force on the curved surface.

basic drawing attached.

Please explain how this will help your car. if my drawing is incorrect please make one illustrating how it will work/help.

...so, where do we mount the "spoons" on our cars? Ahead of the tires or behind them? (wink,wink)?!?!?

Joe, you've sloshed the idea a bit. The OP has determined that flow upward from the read surface of the tires is hitting the area inside the wheel well, just above the 90 degree intersection to the bumpers lower edge. He placed a coanda device in the wheel well behind the tire, effectively training flow spryay from the tire tread down to the lower edge of the bumper without causing it to"slam"into the flat edge inside the wheel well, then be forced outward and around the square edges of the bumper. If it works, it should have some positive effect, similar to rounding the forward edge of the rear bumper, but without actually modifying the vehicle.

You've also gotten the water effect completely wrong. The coanda effect is best demonstrated using free flowing fluid under gravity. Introduce the flat side of a half sphere perpendicular to the flow, and it will spread over the surface, then follow the curvature of the sphere after the 90 degree drop, leaving the new flow in approximately the same place as the uninterrupted flow would have been.

However, if you introduce the same hemisphere, only with the flat side both parallel, and facing AWAY from the flow, the water flow will trail the arc until it has no more kinetic energy, then will fall to gravity again at that point, which could be several inches from the initial flow.

I don't get it.

if the "thrust" is supposed to be from low pressure, then it will pull back on the tire as well as the plastic restriction.

Where does the "thruster" part come from?

It doesn't, dave, and the coanda effect can never effect thrust, since that would require the addition of energy, something coanda doesn't do. Coanda's effect is that of direction change through utilization of nearly all of the existing energy. In the example I provided, coanda removes nearly all the kinetic energy given by gravity, until the flow of water reaches an exhaustion point, where gravity takes over again.

hi all,
today i added a pair of coanda thrusters behind the front wheels ,
now this ones Really made a noticeable difference,
the first ones i couldn't really tell since i put them on right after i did my differential,so i wasn't quite sure which was what

but now i know they make a positive impact,
you should all try and see, its really a 3 min. mode, and free...just find the right bottle

one more thing,
i was surprised that they start to show some results at relatively low speed,
starting from around 20 mph on..

please post your testing methods in addition to your claims. How did you measure the difference and what did you use for a control?

When I see positive ABA test results, I'll look for the unicorn.

Like i said in my first post, i smell poop

I will admit my wife's Hyundai Elantra has two factory-installed rounded tabs behind the front wheels, narrower than the tread width, protruding below the body line an inch or two.

^^^have pics? i'm curious

I was mistaken. They're in front of the rear wheels. The car is a 2006 Hyundai Elantra.
http://i268.photobucket.com/albums/j..._4236Small.jpg
http://i268.photobucket.com/albums/j..._4234Small.jpg
http://i268.photobucket.com/albums/j..._4235Small.jpg

ah, aka spats
http://ecomodder.com/forum/showthrea...ats-13669.html