TAS vs. flap reflex angle

[ELIPPSE]

I recently did a flight test of my Lancair 235 testing TAS, true air
speed, vs. the reflex angle of the flaps, i.e. angle of the flaps above
the wing surface. The test was flown at 1535 lb, 11,000' density
altitude, full-throttle, leaned for max rpm.

+8 deg. - 196.2mph; +6 deg. - 199.7mph; +4 deg. - 196.2mph

+2 deg. - 189.3mph.

The test demonstrated that careful adjustment of the flap reflex angle
on Lancair or other aircraft so-equipped can result in higher TAS. The
reflex angle is sensitive to IAS and weight. As IAS decreases or weight
increases, L/D increases with less reflex, more camber and lower body
angle. An additional positive effect is that at the lower body angle,
vision over the nose is enhanced!

[Tim Ward]

"ELIPPSE" > wrote in message
ups.com...
> I recently did a flight test of my Lancair 235 testing TAS, true air
> speed, vs. the reflex angle of the flaps, i.e. angle of the flaps above
> the wing surface. The test was flown at 1535 lb, 11,000' density
> altitude, full-throttle, leaned for max rpm.
>
> +8 deg. - 196.2mph; +6 deg. - 199.7mph; +4 deg. - 196.2mph
>
> +2 deg. - 189.3mph.
>
> The test demonstrated that careful adjustment of the flap reflex angle
> on Lancair or other aircraft so-equipped can result in higher TAS. The
> reflex angle is sensitive to IAS and weight. As IAS decreases or weight
> increases, L/D increases with less reflex, more camber and lower body
> angle. An additional positive effect is that at the lower body angle,
> vision over the nose is enhanced!

The nomenclature that sailplane pilots use for "reflex" is "negative flap".

You'll probably want to build a wing drag rake as shown at:
http://www.owp.us/Johnson/AtLast.asp

so that you can find minimum wing drag easily.

Do your ailerons reflex along with the flaps?

Tim Ward

[Wayne Paul]

"Tim Ward" > wrote in message
ink.net...
> You'll probably want to build a wing drag rake as shown at:
> http://www.owp.us/Johnson/AtLast.asp
>
> so that you can find minimum wing drag easily.
>
> Do your ailerons reflex along with the flaps?
>
> Tim Ward
>

Tim,

That sure looks like the page I created from Dick's article back in Feb,
2003!

http://www.soaridaho.com/Schreder/Technical/Drag_Rake/Dick_Johnson.htm

It even has the typo that I haven't corrected.

Wayne
http://www.soaridaho.com/

[Tim Ward]

"Wayne Paul" > wrote in message
...
>
> "Tim Ward" > wrote in message
> ink.net...
> > You'll probably want to build a wing drag rake as shown at:
> > http://www.owp.us/Johnson/AtLast.asp
> >
> > so that you can find minimum wing drag easily.
> >
> > Do your ailerons reflex along with the flaps?
> >
> > Tim Ward
> >
>
> Tim,
>
> That sure looks like the page I created from Dick's article back in Feb,
> 2003!
>
> http://www.soaridaho.com/Schreder/Technical/Drag_Rake/Dick_Johnson.htm
>
> It even has the typo that I haven't corrected.
>
> Wayne
> http://www.soaridaho.com/
>
>

I knew I'd seen it somewhere else. You realize, I'm not claiming it as my
work.

Tim Ward