DSing a Wowing

[TSnake]

I'm just starting to learn how to DS (Dynamic Soaring), and I'm after a little advice.
I tried my Skua S15 today for the first time, and it was ... OK, but washed off too much speed on the "dark side". The problem may be that it doesn't have a ballast tube fitted, and is crying out for more weight (although it does weigh in at a porky 1.2 kg as it is).

The Booby on the other hand, weighs just 1 kg, and is light years ahead of the S15 when it comes to DSing.
Both models get buffeted badly by the turbulant air, but the Booby retains enough speed to "shrug it off" and keep going, whereas the S15 becomes a bit of a handfull.

Does anyone have any advice they can pass on ?
Has anyone tried this before ?

[TSnake]

Well in spite of the overwhelming enthusiasm for this thread, I'm still DSing the Booby every other day.
The main thing I've learnt is...... wow this thing is durable !

I've lost count of the number of times I've smashed it into trees and boulders at full speed, and it's still flying.

A great Dynamic Soaring trainer.

[AussieJarred]

haha, i learnededededd to ds the duck at point cartwright today... and about the skua, just add a shoot load of the lead strips tyre places use on the bottom, thattle work

[TSnake]

Yes, I've been meaning to try that for ages, but I just have trouble with the idea of making the Skua even heavier than it is.
But you're right, that is what I have to do.

I just re-covered my Booby with some packing tape, and I gotta admit, it looks pretty good.

I actually thought that buying the Booby was a mistake when I first tried to fly it, I never thought it would even fly.
But now that I've flown it a few hundred times, it gives me chills every time I throw it up, love it.]

[raymo]

Hi everyone, This may sound a bit silly, but can someone explain to me, if it's not too complicated, what dynamic soaring is?

[TSnake]

Umm, it's actually a really good question.
I can do it, but I still don't fully understand how it works.
As far as I can tell, there's no simple way to explain the science behind it.

You basically fly in a "flatish" loop, spending most of the time on the back (sheltered from the wind) side of a slope, forcing the plane to just push through the shear layer at the edge, then turn back around and re-enter the back side.
It sounds crazy, but the plane gets faster with every loop, and have been clocked at over 390 MPH.

To quote somebody who's alot smarter than me...

How and Why Does Dynamic Soaring (DS) Work?
Mark Drela

A DS'ing glider gets its energy the same way as a sailboat -- by using forces generated in two media moving past each other. Except a DS'ing glider does this cyclically rather than continuously.

In DS, the fast air above the shear layer is "the wind", and the still air under the shear layer is "the water". When the glider does the sharp turn above the layer its wing is acting as a sail. When it does a sharp turn below the layer its wing is acting as a "keel".

It's better to look at how DS works via energy rather than forces. Each time the shear layer is penetrated at a shallow angle, there is an increase in airspeed of delta(V) and hence the glider's kinetic energy relative to the new airmass also increases. So the glider gets a K.E. kick every time the shear layer is pierced.

[raymo]

Thanks for that. I think I understand how it works.

[seeker]

Might want to play with the cg and lower your control throws. I noticed a big difference in my 1200 when I got the cg spot on, Big throws are great for aerobatics, but can be very draggy. I use about 5mm of elevator and almost never go full throw.
Jon McConnaughey

[TSnake]

I've changed my mind about the Booby being "a great dynamic soaring trainer".

I'm starting to get a little more serious about DSing, and I bought a Jazz Xtreme on a recommendation from a really good DSer.
I got to do a direct comparison today, and there is no comparison..... the Jazz will fly circles around the Booby any day (bad pun intended) :)

Maybe in cyclonic winds, the Booby might be able to hold its own, but winds that strong would "blow out" the DS site.
When flying the Jazz, I always had options, I could change my line whenever I wanted, but the Booby was always on the edge of its capabilities.
When I tried to push too hard, the Booby just runs out of elevator and plows into the ground. If I give it more elevator travel, it does what Booby's do and gets all draggy and stally.

I still love the Booby, but it's not a good DS trainer. :(