Coanda Effect

[Flymach2]

Hi...

Just wondering what some of the thoughts are on Coanda Effect when applying the theory to an asymmetrical airfoil. Do you think in addition to Bernoulli's and Newton's that Coanda plays a role in assisting in the lift generation? I've recently conducted a simple experiment which seemed to lean in the direction of an affirmative result. Curious on the thoughts of others on this. Thanks.

Regards

 

[FearlessFreep]

There have been a number of aircraft that were designed to take advantage of the coanda effect. If I remember it correctly it was I think the Boeing YC-15 or 16 that used it for STOL performance. Don't hold me to that designator, it has been a longtime since I have heard about it. There is also a Russian aircraft that was designed in a similar manner.

Other than that I have not heard much about it's utilization. It would be interesting to do a search on this. You might want to check Avaition Week & Space Technology website and search on Coanda, that might come up with some information.

Interesting topic.

 

[Timebuilder]

I'm currently reading a fascinating website on lift and the coanda effect. If you like the "incorrect lift" website, you will enjoy this one, too.

http://www.jefraskin.com/forjef2/jefweb-compiled/published/coanda_effect.html

 

[avbug]

Coanda effect is the reason that the NOTAR helicopters don't need tail rotors. It isn't the deflector at the end of the tailcone. That's only there for directional assistance, but the anti torque capability comes from coanda effect. The cold blower on the end only serves to assist in directional control.

 

[Flymach2]

Hi...

It does seem that Coanda Effect is not referred to much when considering aerodynamic efficiency and/or lift generating capabilities of an airfoil. I think, perhaps, that the reason for this is because it can actually be mistaken as Bernoulli's. Whether or not I'm correct in my assumption...I don't know.

Avbug,
I'm trying to correlate the Coanda Effect with aerodynamics of the NOTAR helicopter....I'm not sure I follow. I can see how it would effect the aircraft in forward flight, but I can't see it any other phase of flight. If you have a free moment could you try to relate it for me?

Thanks to all who have responded.

Regards

 

[Veronaut]

Here's a good link for info on Coanda:

http://humane.sourceforge.net/jefweb-compiled/published/coanda_effect.html

What is also interesting in the website above is the airfoil that Einstein developed using Bernoulli's principle, that really didn't get off the ground (pun definitely intended).

 

[Timebuilder]

The link above contains the same content as the link I posted.

 

[A Squared]

Flymach,

On the NOTAR, the entire talboom is pressurized, there are slits along the length of the tail boom which direct air downward around the boom. Coanda effect creates an anti-torque force from this airflow. The nozzle is just for directional control, like AVbug.

THis is a pretty simplified version of what's going on, but it covers the basics.

regards

 

[avbug]

Additionaly, airlfow is uneven around the round boom due to the shape fo the metal lip over the slits that A Squared described. This serves to serve coanda effect due to vertical airflow (downwash) from the rotor disc.

 

[TurboS7]

We have friends that live on coanda drive, I wondered where they got that name from.

 

[Flymach2]

Hi...

Thanks to all for their information.

The application of the Coanda theory to the NOTAR is interesting. I wasn't aware of the length-wise slits in the tail boom. Makes more sense now. Thanks for the input.

Why do you think that Coanda isn't really talked about in the training environment? I can see where it may get confusing when attempting to apply the theory to different types of airfoil design, but it should be part of basic aerodynamics.

Regards

 

[Bluto]

Flymach2,
You're a geek.

 

[Flymach2]

Hi...

Hey thanks, Bluto....I appreciate that. I was born this way....what's your excuse? I know where you live and I know where you sleep.....be afraid.....be very afraid.

Regards