The Windward Turd Theory
 

There, I fixed that for you. No comment on the "theory" yet though.

Why is it utter rubbish?
dynamic soaring on the leeward side of ridges is very popular in the model gliding world. It's principally the same thing.

He has a new theory. Have a read.

Thanks. The board won't like me put up links yet.

Looking forward to reading your opinion on this.

According to the author, this effect is what produces lift and not the wind gradient.

If you write "Dynamic Soaring for Birds," I guess the target audience is birdbrains.

I think the description of loss and gain of kinetic energy may actually be correct, when viewed from a ground-based frame of reference. But the kinetic energy determined from that frame of reference is wholly irrelevant -- until it's time to land, anyway.

I've actually had significant communications with the author- he tried pushing this barrow on some physics sites I hang around on.

It was explained to him ad nauseum that you cannot gain lift by turning in a constant wind, but he was unreachable by logic and facts.

He's also a "downwind turn" proponent, which tells you all you need to know.

Most worrying thing is he is also still an active instructor......

The point of dynamic soaring is that the wind isn't constant. Over the sea, there's more of it the higher you go, and there are also gusts, and the ability to slope soar over the crests of waves. I have the flu and my brain is currently too fuggy to contemplate his exact theory though.

He is postulating a reverse of the "Downwind-turn"- he thinks by gaining groundspeed downwind, then turning into-wind, you gain airspeed and can climb.

It's barking, but he won't be told.

Just out of curiosity:

Dynamic Soaring is completely real, just not the way the gut in the OP believes it to be.

Presentation about dynamic soaring by the present speed record holder.

about an hour long

I have been aware of apparently ludicrous speed claims on youtube for years and have often wondered if they were actually true.

The speaker in the video, Spencer Lisenby, seems convincing.

519mph and running into transonic effects.

The next glider will be swept wing.

I wonder if there is a theoretical speed limit?

Dynamic Soaring depends on crossing wind gradients. This guy's theory is about "dynamic soaring" without crossing wind gradients.

Second paragraph from the top.

As someone else remarked, the opposite of the "downwind turn". If you start with the belief that you can gain airspeed by turning from crosswind to upwind, you know that everything which follows is nonsense.

Exactly. I don't know why some people insist this is the case. It's almost like a mental illness.

Of course, we're overlooking the real problem with the theory -- it doesn't account for the much larger kinetic energy effect of east and west turns. :}

Quote (my emphasis):
"In a leeward turn, aerodynamic forces combined with a large angle of bank and a large angle of drift provide a propulsive force enabling acquisition of ground momentum and ground kinetic energy without gaining airspeed or losing potential energy. During the climbing part of the wing-over, extra potential energy is gained due to the propulsive force."


What "propulsive force"? I may be missing something (don't answer that!) but, on the face of it, that is gobbledygook. Pity, because the sight of an albatross sustaining flight - mainly in ground-effect - with no apparent form of propulsion is awe-inspiring.

Cannot see how - assuming the wind is horizontal and constant at any given height above the sea - energy can be harvested to maintain flight-sustaining airspeed simply by manoeuvring. Sounds like "perpetual-motion" to me.

Same as Windmills, it is Perpetual Motion..... Until the wind stops.
.

I don't understand and me 'ead 'urts! :confused:

I always thought seabirds were just ridge soaring on waves.

Presume you are being frivolous? In case not: windmills can harvest energy from the wind because they are anchored to terra-firma Flying machines are not...

Yeah, he thinks he’s found an all new force that everyone else has missed.

Nothing new here Its the same force that makes your groundspeed increase when you turn downwind and decrease when you turn upwind

Its obviously Coriolis, So all you northerners please be careful when you do your downwind turns down under

No, no it isn't.....

No, not at all where he is coming from. In his rather daft opinion, a headwind increases the speed of the relative wind (airspeed). This is a newbie/layman's mistake, I hear this spoken and see it written all the time, it's a pet hate of mine. He's taken the fact that a takeoff into wind is useful and turned it into a gain in lift whenever you point into wind in free flight. He's an idiot.

The CAA and FAA should do more to dispel this BS. Apparently this guy is/was an instructor with CAA certification. How many more jokers like him out there then?

I was a keen Aerobatic plot back in the day. I had an "interesting" conversation with no less than the chief pilot of a major airline, also an Aerobat, who insisted you would get a longer vertical line if you pulled into it downwind, as you had more kinetic energy.

Attempts at explaining frames of reference went no where.

And before anyone pipes in, vertical lines were not supposed to be corrected for wind, the judges were supposed to allow for the fact that you would drift.

I'm not entirely surprised that it goes that far up having met so many with the same stupid gene. There should be no hiding place for such people, certainly isn't in the military, but the CAA and FAA aren't interested. I spoke to some retired CAA guy who claimed the whole debate was a 'matter of opinion'.

That's gonna be tough. No dealings with the CAA but I would bet long odds that I could easily find FAA inspectors who believe in the downwind turn myth.

Just keeping it local, speeds approximate and in knots:
At the Equator: 970kn
Earth orbital speed around Sun: 58,000kn
Sun orbital speed around galaxy: 447,000kn (Really?)
Less local:
Galaxy through space: 1,166,310kn

So, when you make a 180 in your 50kn glider you change from going forwards at over a million knots to backwards at the same speed.
Better lock your hold on those flight controls! ;)

p.s. Foregoing a bit of Shiraz induced reductio ad absurdum - did you notice?

Richard Collins, editor of the US Flying magazine was a believer, writing articles about it.

Another of his mantras was that if a modification meant an engine delivered more power, it MUST increase fuel burn.

"Efficiency" was apparently a foreign concept to him.

It's the equivalent of flat Earth and Apollo hoax.

If the vertical line was established by bouncing the airplane off a trampoline mounted to the ground at a 45 degree angle... :ugh:

Interesting, I did not know that about Collins.

Actually, after a little googling, I think I defamed Collins- it was J McClellan, also a former Flying editor, who wrote an article full of all the non-science associated with the downwind turn myth.

I know a good lawyer ...

There are lots of good lawyers- but do you know a good one who is also alive?

In the early days I was struggling with S&L in an out-of-trim Cherokee, and was discouraged from "playing" with the rudder trim on the basis that the tendency for it to keep flying one wing down was because of the crosswind...

In recent days in an airliner, (which was a bit crooked) I was approaching to land with some aileron trim to the left, to hold a neutral force. The other pilot pointed out that we're expecting a right crosswind and I'm trimmed against the crosswind. I pointed out that it's trimmed neutral right now (and physically let go of the yoke to show him) and expected him to realize his brainfart. No, he persisted in trying to convince me that "I'm just making my job harder" being trimmed against the crosswind. I wish I was kidding.

Ask him this:
 

Someone should ask him:

"Is there any conceivable air data instrument that you could stick onto an aircraft (or a bird) that would tell you what said aircraft or bird was doing relative to the ground?"

"Is there any conceivable air data instrument that you could stick onto an aircraft (or a bird) that would tell you what the wind was doing?"

It's astounding the difficulty people have with the concept of frames of reference.

Take out a pencil and re-label the current position of the aileron trim indicator, "Neutral," wink at the other pilot, and say, "Thanks for catching that."

Neither here nor there, but I love birds:

Aren't albatrosses effectively doing wave soaring: positioning themselves in the updraft part of the standing waves that are created when a constant wind blows over an irregular surface? With the irregular surface being the ocean? Constant speed wind striking the face of an ocean wave is very much like constant speed wind striking a mountain ridge: enormous updraft starting from the windward face and extending up and to leeward -- monster downsmashing rotor immediately to leeward of the wave crest / mountain peak. Albatross knows enough to stay in the updraft.