Winter build project: Wolfgang Matt’s ATLAS

JonTappin wrote: Not sure it is going to be much, if any, slower than the BA though as per an earlier post. Is this assumption down to the straight wing vs swept or something else,eg wing section thickness?

This is in reference to a quote from Wolfgang Matt back in 1976:

Q: You seem to prefer a straight taper configuration. Any reason for this?
A: I tried swept wings, but this design needs more speed which requires a faster flying style. I do not like a fast flying style that much

I'm not wholly convinced by this argument but this is what he thought 40-years ago.

However, the Atlas does (I think) have a thicker aerofoil. I think I read 22% somewhere, although this does seem a little too much. The BA is a more typical 18% section. This might have an effect on the speed?

Mike beat me to it as I managed to write my post and then somehow lost it!

Mike, thanks for editing my last post, was I incoherent, inadvertently rude to Phil, or did I call your Blue Angel and Blue Angle again... or was it some other misdemeanor .

I know a google search would probably answer my question, but what does 22% aerofoil mean, 22% of what? Is there an idiots guide to wing shapes and aerofoils that anyone can point me in the direction of.

I edited because you had missed the word 'on' in the last sentence.

22% refers to how thick it is compared to its length. Since you have the plan, can you measure the length of the wing root section and the maximum thickness. Then do thickness divided by length x100 to find the percentage thickness.

As for an idiots guide, do a google search on NACA and Eppler for some insight.

...and Martin Hepperle has loads of info on his website

www.mh-aerotools.de/airfoils/index.htm

MikeSeale wrote:

JonTappin wrote: Not sure it is going to be much, if any, slower than the BA though as per an earlier post. Is this assumption down to the straight wing vs swept or something else,eg wing section thickness?

This is in reference to a quote from Wolfgang Matt back in 1976:

Q: You seem to prefer a straight taper configuration. Any reason for this?
A: I tried swept wings, but this design needs more speed which requires a faster flying style. I do not like a fast flying style that much

I'm not wholly convinced by this argument but this is what he thought 40-years ago.

However, the Atlas does (I think) have a thicker aerofoil. I think I read 22% somewhere, although this does seem a little too much. The BA is a more typical 18% section. This might have an effect on the speed?

I read that as a swept wing needs to fly faster, rather than it will be faster.

However a thicker wing section will slow it down and should also lower the stall speed, although wing loading will also be a factor.

We shall see!

MikeSeale wrote: ...Since you have the plan, can you measure the length of the wing root section and the maximum thickness. Then do thickness divided by length x100 to find the percentage thickness.

Length: 337mm
Maximum thickness:63mm
Percentage thickness: 18.7%

So that would make it similar to the Blue Angel?