This from another thread :
Nestor wrote:
Article writes “Choice for the square-shaped wing dates back from 1972. … Even if the RA16-3C3 profile gives good results at low speeds, with sound stalls, the square shape, the constant thickness profile, the wing area and aspect ratio are severe handicaps preventing higher speeds.
Above from an article that was posted here a few months ago.
Not the characteristics of a laminar-flow wing profile.
Since the OP flys on this “thick” wing, I would not expect any speed increase dirty vs clean wing.
Yes, a couple of big rocks or 2 feet of mud on the wing will slow down a C-172 .. I know that too :-)
I think the Cirrus and the Columbia, who have very similar wings, are on the edge of beeing “true laminar airfoils”. Compared to a PA-28 or C-1xxm sure.
The Lancair Columbia wing NLF(2)-0215(H) that’s a NASA developed Natural Laminar Flow profile #215
Here it is :
http://airfoiltools.com/airfoil/details?airfoil=nlf0215f-il
Not sure how it compares to the Roncz profile used on all Cirrus .
I can tell you that the Lancair will BLOW THE DOORS OFF the SR22 @ same weight and HP …
Interesting site!
It’s actually very similar to the Airfoil RONCZ designed for the SR22, if I remember that correctly
Michael wrote:
I can tell you that the Lancair will BLOW THE DOORS OFF the SR22 @ same weight and HP …
Yes, while you sit in a cramped cabin and watch the outside world through slots :-)
:-P
My opinion: Yes, the Columbia/TTx is faster than the 22T (we can only compare the turbo models) but in real life the big cabin, the better visibility and the CAPS system is of more value – for me!
Flyer59 wrote:
(we can only compare the turbo models)
Why’s that ? I’ll race any SR22, any day of the week.
Have you flown a Lancair ? I ask cause I don’t believe the remark about better visi is justified. I’ve flown many models of Cirrus and would not say that visi is much different than the Lancair.
IMHO: The CAPS is not worth the cost nor the weight, period.
Back to the opening question: with no kind of engineering degree and with no relevant experience, I can only think
-) that cleaning the plane will remove some weight which will always help performance
-) that cleaner surfaces create less turbulence, hence less parasitary drag, again contributing to performance
How much is gained depends on very many parameters, I can well imagine that in the vast majority of cases the gain is close to imperceptible.
I have flown these Lancairs: 360, ES, IV-P, Columbia 300 and 400, Legacy. Maybe 30 hours altogether. The visibility cannot be compared, nor can you compare the cabin.
I really liked the 400 though!
Well, 100 surviving pilost have a very different opinion about CAPS. But let’s not get into that. It’s a tiring discussion and I really have enough of that.
Want to compare all data of the SR22T G5 and the TTx?
Of course you will win that race! I know the Coumbia is faster than the SR22. But that’s about the only advantage it has.
Michael wrote:
IMHO: The CAPS is not worth the cost nor the weight, period.
That’s an interesting statement! Why would an escape for situations like:
- engine failure at night or over terrain
- structural failure
- loss of control
- Pilot Incapacitation
- Midair collision
… not be worth the money?
