Where would one buy these fences? I was told they are aftermarket mods, but it seems like every ASW-28 has them installed. Where can they be purchased from? I contacted Schleicher but so far have not gotten any response.

On Wednesday, 26 May 2021 at 22:52:41 UTC+3, soaringjac wrote:
> Where would one buy these fences? I was told they are aftermarket mods, but it seems like every ASW-28 has them installed. Where can they be purchased from? I contacted Schleicher but so far have not gotten any response.

"In 2006, a project had been initiated to measure
the loss in overall performance by applying for
example four additional pairs of fences on the
wings of an ASW-28 (Fig. 1). The result was a
decrease in maximum L/D of about 0.25 points
for a singe pair of fences"

https://tu-dresden.de/ing/maschinenwesen/ilr/fmr/ressourcen/dateien/dateien/berichte/140303_TS.pdf?lang=en

On Wednesday, 26 May 2021 at 21:27:23 UTC+1, krasw wrote:
> On Wednesday, 26 May 2021 at 22:52:41 UTC+3, soaringjac wrote:
> > Where would one buy these fences? I was told they are aftermarket mods, but it seems like every ASW-28 has them installed. Where can they be purchased from? I contacted Schleicher but so far have not gotten any response.
> "In 2006, a project had been initiated to measure
> the loss in overall performance by applying for
> example four additional pairs of fences on the
> wings of an ASW-28 (Fig. 1). The result was a
> decrease in maximum L/D of about 0.25 points
> for a singe pair of fences"
>
> https://tu-dresden.de/ing/maschinenwesen/ilr/fmr/ressourcen/dateien/dateien/berichte/140303_TS.pdf?lang=en

An airline pilot friend, with an aeronautics degree, said the delta is one of the highest drag shapes there is if the airflow isn't in line.

Even with a winglet on the end, I don't see why airflow over the wing would be directly in line; surely there's bound to be some spanwise element in the flow, hence at some angle to the blade

On Wednesday, May 26, 2021 at 6:18:51 PM UTC-4, andy l wrote:
> On Wednesday, 26 May 2021 at 21:27:23 UTC+1, krasw wrote:
> > On Wednesday, 26 May 2021 at 22:52:41 UTC+3, soaringjac wrote:
> > > Where would one buy these fences? I was told they are aftermarket mods, but it seems like every ASW-28 has them installed. Where can they be purchased from? I contacted Schleicher but so far have not gotten any response.
> > "In 2006, a project had been initiated to measure
> > the loss in overall performance by applying for
> > example four additional pairs of fences on the
> > wings of an ASW-28 (Fig. 1). The result was a
> > decrease in maximum L/D of about 0.25 points
> > for a singe pair of fences"
> >
> > https://tu-dresden.de/ing/maschinenwesen/ilr/fmr/ressourcen/dateien/dateien/berichte/140303_TS.pdf?lang=en
> An airline pilot friend, with an aeronautics degree, said the delta is one of the highest drag shapes there is if the airflow isn't in line.
>
> Even with a winglet on the end, I don't see why airflow over the wing would be directly in line; surely there's bound to be some spanwise element in the flow, hence at some angle to the blade

<< ... I don't see why airflow over the wing would be directly in line; surely there's bound to be some spanwise element in the flow, hence at some angle to the blade. >>
That's an interesting thought. One could apply some tufting and install a GoPro on the outer edge of the elevator trained onto that area around the aileron. That way, one would know if a fence makes sense or not.

Uli
'AS'

On Wednesday, 26 May 2021 at 23:38:50 UTC+1, AS wrote:
> On Wednesday, May 26, 2021 at 6:18:51 PM UTC-4, andy l wrote:
> > On Wednesday, 26 May 2021 at 21:27:23 UTC+1, krasw wrote:
> > > On Wednesday, 26 May 2021 at 22:52:41 UTC+3, soaringjac wrote:
> > > > Where would one buy these fences? I was told they are aftermarket mods, but it seems like every ASW-28 has them installed. Where can they be purchased from? I contacted Schleicher but so far have not gotten any response.
> > > "In 2006, a project had been initiated to measure
> > > the loss in overall performance by applying for
> > > example four additional pairs of fences on the
> > > wings of an ASW-28 (Fig. 1). The result was a
> > > decrease in maximum L/D of about 0.25 points
> > > for a singe pair of fences"
> > >
> > > https://tu-dresden.de/ing/maschinenwesen/ilr/fmr/ressourcen/dateien/dateien/berichte/140303_TS.pdf?lang=en
> > An airline pilot friend, with an aeronautics degree, said the delta is one of the highest drag shapes there is if the airflow isn't in line.
> >
> > Even with a winglet on the end, I don't see why airflow over the wing would be directly in line; surely there's bound to be some spanwise element in the flow, hence at some angle to the blade
> << ... I don't see why airflow over the wing would be directly in line; surely there's bound to be some spanwise element in the flow, hence at some angle to the blade. >>
> That's an interesting thought. One could apply some tufting and install a GoPro on the outer edge of the elevator trained onto that area around the aileron. That way, one would know if a fence makes sense or not.
>
> Uli
> 'AS'

I hope you didn't mean the elevator, but besides that, why bother

Of course it doesnt make sense, or if 2 per wing was good, more would be better and wings everywhere would have loads on. Those little upward folded ribs on the outside of Cessna flaps are surely there to stiffen the surface, not to gain aerodynamic benefit

For what proportion of the flight is the aileron moving anyway? Yes maybe slightly too much with some people, but not much overall.