Tuesday, October 6, 2015

A beautiful illustration of aircraft wake turbulence

All aircraft leave a trail of wake turbulence behind them as they pass through the air.  Light planes don't leave much at all, but the larger airliners leave so much that following traffic has to be separated from them by several miles to avoid potential problems.  This is known as wake vortex separation.

Here's a fascinating video of Boeing 777 airliners, among the largest in the sky, and the wake vortices and turbulence they produce.  The cloudy, moist air through which they're flying allows condensation to form, revealing air patterns, and their wake disturbs the clouds to show how following aircraft might be affected by downdrafts and other hazards.  Watch it in full-screen mode for best results.




Charlie Mitchell said...

Yeah, people seem to think that a jet leaves an area of disturbance that is about the same size as the jet's cross-section (not that big, in other words).
They actually leave a huge swath of roiling boiling disturbance.
Pretty from a distance, but you don't want to fly through it.

Quartermaster said...

Over at XBradTC's place he has posted a clip with a Blackhawk launching from a civil airport. The next aircraft in the frame is a Cirrus SR-20 or 22 crashing from the Rotor tip vortices. The wake of a chopper if quite dangerous to light aircraft, and the heavier the aircraft, rotary wing or fixed wing, the worse the wake turbulence will be. It also takes several minutes for the turbulence to die down.

Dangerous stuff.

Old NFO said...

Looks pretty, will literally slap an airplane out of the air...

Charlie Mitchell said...

Question -
I read somewhere about those little winglets(?) - the little upward-pointing wingtip extensions. Weren't they designed to reduce this type of turbulence? I always see them now on 747s, so I wonder why this 777 doesn't have them.

Old Surfer said...

Re winglets, I believe this aircraft has what might be called diffuser wingtips, twisted and shaped to reduce the tip vortex. The shots where fog is forming over the whole wing show a perfect elliptical lift distribution without visible tip vortices.
Even a very light aircraft like a hang-glider can produce a wake dangerous to another similar aircraft - I got rolled into a 90* bank getting too close to another glider once, and the wakes from gliders below and upwind in a slope soaring situation can shake you up. I believe one of the pioneer Wills brothers was killed by a helicopter wake while filming a hang-gliding movie.