22
$\begingroup$

Considering that Wing-In-Ground-Effect (WIGE) vehicles fly with a rather low ground clearance, there is not much room for banking. How do WIGE vehicles turn? Do they turn just very slow with a low bank angle? Or do they turn uncoordinated with wings level?

I can imagine that banking has an opposite effect: the raised wing has less ground effect so more drag so it creates some countering yaw moment. Is this correct?

$\endgroup$
  • 8
    $\begingroup$ "carefully" .... $\endgroup$ – Fattie Mar 24 at 19:54
  • $\begingroup$ Wouldn't the raised wing have less drag, because it's experiencing less ground effect, ergo producing less lift, ergo generating less induced drag? $\endgroup$ – Sean Mar 25 at 2:51
  • 2
    $\begingroup$ @Sean, no: the essence of the ground effect that you get more lift for the same drag. Or same lfit with less drag. Also, if you are in a sustained banked turn, then by definition both half-wings produce the same lift - otherwise you'd be rolling with acceleration. It follows that the surface that is less in ground effect will have more drag. (Plus there are usual effects due to ailerons position etc. - which usually contribute with the same sign). $\endgroup$ – Zeus Mar 25 at 4:54
16
$\begingroup$

It turns like an airplane by tilting the lift vector. Watch carefully in this video, especially about 50 seconds in, and you can see the craft is turning by banking.

enter image description here

It just can't bank very hard unless it climbs a little higher. This is one of the problems of GE aircraft; they aren't very maneuverable because they can only make gentle turns at the normal cruising level close to the surface.

The alternative to banking, if you don't have enough room to roll, is skidding, where you are redirecting the thrust vector and also generating some lateral force from the sideways presentation of the craft's body. Basically like a hovercraft. A lot less efficient though because of the drag rise from the skid. Some of those really big GE machines like the Ekranoplan would have used skidding (kind of obvious from the huge rudder that it's designed to skid) and maybe a little bit of bank.

It's probably a good thing that this concept has not been all that successful. If the world was full of these types of machines crisscrossing every which way over oceans and lakes, all at the same level and going pretty fast, you probably have a lot more mid-airs than you get with airplanes, or boat collisions for that matter.

$\endgroup$
  • $\begingroup$ How did large versions like the Ekranoplan turn? Looks like there's a fairly large rudder, and engine thrust might have been used. There doesn't seem to be much margin for bank angle. $\endgroup$ – rcgldr Mar 24 at 18:44
  • $\begingroup$ It never occurred to me that such craft would indeed "meet" - just like ground vehicles! You'd need stop signs and so on. $\endgroup$ – Fattie Mar 24 at 19:54
  • 2
    $\begingroup$ @rcgldr thanks for the mention I added an extra paragraph to address that. $\endgroup$ – John K Mar 24 at 20:01
  • 1
    $\begingroup$ Stop signs on buoys! That would be rather funny, @Fattie! $\endgroup$ – FreeMan Mar 25 at 12:34
  • $\begingroup$ @FreeMan - right :) $\endgroup$ – Fattie Mar 25 at 12:36

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.