On Sat, 06 Jun 2015 06:32:10 -0700, platypterus101 wrote:

On Saturday, June 6, 2015 at 7:59:13 AM UTC-5, Martin Gregorie wrote:

No. The main effect of well-designed airbrakes is to reduce effective
lifting surface, but, as a side effect is to add drag, most gliders
will need the stick to be eased forward a little to keep the airspeed
constant. However, the wind gradient and turbulence will probably be
more significant: you'll think you're correcting for these factors
rather than for the extra drag from the brakes. But, as I said above,
it does depend on the glider. For the G103 to behave as it does, its
drag must reduce along with the lift as you open the brakes.
Conversely, the Puchacz has huge speed-limiting upper and lower surface
brakes: so much so that it would be surprising if shoving those out in
the breeze didn't show it down.

One could steer this conversation in the direction of transient versus
steady-state effects.

Kindly stop changing the subject. You asked about transient effects when
the brakes are opened. I passed on personal experience of flying gliders
with a range of behaviour when the brakes are opened, which is what you
asked about.

There is only valid answer: "what happens depends on which glider you're
flying", i.e. there is no single universal answer. Live with it.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |