-2
$\begingroup$

Well, I don't know much about this type of mechanism, and the only post I could find that has something similar to what I'm asking is this one, but isn't quite what I'm asking.

So, the idea would be to expel hot air from holes (or other means) on the surface of the wings in order to increase the lift (or diminish the drag) on wings.

Like what I said, the only airplane that uses such thing is the AN-72, which uses a bit of its exhaust hot gases to increase its lift capabilities. But it is the only aircraft I could find.

I tried to search for "active coanda/magnus effect" and I could only find paid articles, so I can presume this type of technology still is in its early stages?

$\endgroup$
0
2
$\begingroup$

Coanda effect is well known to indirectly participate in lift creation, for any wing.

  1. Lift is the effect of air pressure on the wing surface. It can only happen if air is maintained in contact with the wing. Coanda effect takes a large role in maintaining this contact and preventing boundary layer detachment. This effect is the tendency for a fluid to follow a surface (note this effect doesn't generate lift by itself). A good illustration of Coanda effect:

    enter image description here

    Coanda effect, Wikipedia

  2. The airflow around the wing creates lift by Bernoulli principle, this airflow is naturally generated by the displacement of the wing into the air mass, due to the engines.

  3. This airflow can be increased to increase lift. In AN-72, engine exhausts are located over the wing, gas flow is added to air mass flow, this increases lift. This additional high speed airflow is very useful when the aircraft decelerates and the air mass speed also decreases. Exhaust generated airflow maintains a certain level of lift. A similar concept is the channel wing which was studied in the 50s but is not used today.

  4. To create a similar effect, there is no need to expel air from channels in the wing, but a similar idea is implemented: Flaps and slats.

Flaps and slats when extended, which happens mostly at low speed, create additional ways for air to reach the upper side of the wing (top below):

enter image description here

Slat and flaps principle, Source

When aircraft speed has increased, slats and flaps can be retracted (bottom above), because the additional lift they generate comes with a cost in drag.

As regards to expelling air from holes in the wing, this would likely participate to detaching the boundary layer, and would not increase lift. The tendency is to suck up air from holes, to maintain it in contact and prevent it to transition from laminar to turbulent, see What is the purpose of the tiny doors used by the 787's laminar control?

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.