On Tuesday, September 24, 2019 at 12:09:07 PM UTC-4, son_of_flubber wrote:
On Tuesday, September 24, 2019 at 9:11:31 AM UTC-4, son_of_flubber wrote:
How much does crazing affect Polar?

On Tuesday, September 24, 2019 at 10:15:43 AM UTC-4, Tango Eight wrote:
Not at all (provided that the surface is being maintained).

What does 'the surface is being maintained' mean? Can you 'buff out' crazing to the point that it does not increase drag?

I'm surprised that crazing towards the leading edge does not affect laminar flow. How is crazing different than 'bug factor'?

Does crazing progress to a point where it affects drag? Is it still called crazing when that happens?

Proper maintenance means sanding (we're talking 800 grit and finer here, with a spline board or sanding bar for support) followed by polishing with either white rouge (aka "hard wax") or a very high end auto body polish (e.g. 3M Perfect It), followed by wax. That treatment renders any crazing a non-factor aerodynamically. As crazing progresses, you'll find that you need to repeat this treatment periodically. Your fingers will tell you when. If the finish feels smooth, aerodynamically, it is smooth.

If/when the finish starts shedding chunks of material, flaking or cracking up in a way that cannot be levelled with sanding and polishing, well, that's a different story, and patching or all out refinishing will be required to re-obtain full performance. Some readers will be familiar with a certain rather sketchy looking glider that had been patched (extensively) with spackle... and the hell of it is, that glider went pretty darned well!

T8