gel coat

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?

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

The guy in the cockpit makes up for the craising on the wings.
A couple of wrong decisions by the guy flying the super true laminar perfect winged machine, and a few right decisions by the bondo wing flying guy and they'l be tied lol.

On Tuesday, September 24, 2019 at 1:35:38 PM UTC-4, wrote:
The guy in the cockpit makes up for the craising on the wings.
A couple of wrong decisions by the guy flying the super true laminar perfect winged machine, and a few right decisions by the bondo wing flying guy and they'l be tied lol.

True- BUT- All the points made by good glider preparation are points that don't have to be given back.
From a guy who had two 999 point days this year. One of those made the difference between silver and bronze in nationals.
UH

Yes, agreed. I just finished working up an article regarding 5 principles necessary to win at low performance racing. The first principle is all about preparation.

But one of the other (and imop) more important factors is making the proper inflight decisions necessary to fly further or faster.

You know that the presence of a single point difference between 1st and 2nd place amounts to about a single false-thermal attempt, or maybe a few degrees of heading difference along an energy line. Its the "Moffat" principle revisited; namely "win by not loosing".

True- BUT- All the points made by good glider preparation are points that don't have to be given back.
From a guy who had two 999 point days this year. One of those made the difference between silver and bronze in nationals.
UH

Ironically, UH oversaw/assisted/provided the skilled work (vs. the grunt sanding work) on the glider that was the 1 point beneficiary of a complete refinish job.

No good deed goes unpunished.

JB

On Wednesday, September 25, 2019 at 6:54:50 PM UTC-4, wrote:
True- BUT- All the points made by good glider preparation are points that don't have to be given back.
From a guy who had two 999 point days this year. One of those made the difference between silver and bronze in nationals.
UH

Ironically, UH oversaw/assisted/provided the skilled work (vs. the grunt sanding work) on the glider that was the 1 point beneficiary of a complete refinish job.

No good deed goes unpunished.

JB

The reward was seeing one of my best friends in soaring get his best ever nationals finish.
UH

On Thursday, September 26, 2019 at 8:59:23 AM UTC-4, wrote:
On Wednesday, September 25, 2019 at 6:54:50 PM UTC-4, wrote:
True- BUT- All the points made by good glider preparation are points that don't have to be given back.
From a guy who had two 999 point days this year. One of those made the difference between silver and bronze in nationals.
UH

Ironically, UH oversaw/assisted/provided the skilled work (vs. the grunt sanding work) on the glider that was the 1 point beneficiary of a complete refinish job.

No good deed goes unpunished.

JB

The reward was seeing one of my best friends in soaring get his best ever nationals finish.
UH

Thanks, Hank! It was one of the high points of my 50+ years in soaring. Just to reinforce your message, on the last day I made a 20 mile desperation final glide thru mostly sinking air and took a small penalty because I was slightly below the floor of the finish cylinder. IIRC, if I had been 3 feet lower, I would have lost that one point. Sure, there were all kinds of things I could have done earlier in the flight to more than make up for that. But I didn't. At the end of the flight, it came down to one tenth of one percent on that glide. That was my reward for all those hours spent with you pulling templates off my ASW 24 wing, removing the old gel coat carefully, and then building the profile back up the right way. Thanks, again, for your care and attention (and patience!) in that effort.

The above situation is rare. More typically, having that small extra percentage makes it possible to stay with the fleet moving down a fast leg on a blue day vs. slowly being dropped. It's probably not worth worrying about it unless you're flying competitively but it is for me. We're all different. Fortunately, soaring accommodates all of us.

Chip Bearden
JB