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Author Topic: Why do we have shiny finished?  (Read 2388 times)

Online Gerald Arana

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Why do we have shiny finished?
« on: July 26, 2013, 09:38:36 AM »
I remember a while back about the winner of a speed/economy run with a given amount of "GAS" and a specific engine size.

I'm talking about full size aircraft.

If I remember correctly, it was a glass slipper sailplane converted to power and the finish was dull or sanded with fine sandpaper. The idea is that "air" slides on "air" better than anything else. Howard/Brett, correct me on this if I'm wrong please.

Maybe we don't want our ships to "slide" better especially on the down hill portion of a maneuver?

Jerry

Online Brett Buck

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Re: Why do we have shiny finished?
« Reply #1 on: July 26, 2013, 02:51:32 PM »
I remember a while back about the winner of a speed/economy run with a given amount of "GAS" and a specific engine size.

I'm talking about full size aircraft.

If I remember correctly, it was a glass slipper sailplane converted to power and the finish was dull or sanded with fine sandpaper. The idea is that "air" slides on "air" better than anything else. Howard/Brett, correct me on this if I'm wrong please.

Maybe we don't want our ships to "slide" better especially on the down hill portion of a maneuver?

  We have shiny finishes because we want to win stunt contests!

    Aerodynamically it's probably NOT what we want, in many cases it has appeared that the flow was laminar until something disturbed it, leading to radical changes in the performance at near-random. Getting rain on the wing, for instance.

   Turbulators, vortex generators, etc. are all more-or-less intended to stir everything up on an otherwise smooth wing so the flow doesn't change drastically. In either case it may or may not improve the lift capability, drag, or L/D but that's not nearly as important, and in particular, drag can be your friend (as you note). The wing on the Infinity is not ~2 3/4" thick at the root just to get more lift...

    Brett

Offline proparc

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Re: Why do we have shiny finished?
« Reply #2 on: July 26, 2013, 06:08:52 PM »
Stunt ships are like full size fighter planes; it is not enough that they perform well, they have to look hot. y1
Milton "Proparc" Graham

Offline Tim Wescott

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Re: Why do we have shiny finished?
« Reply #3 on: July 27, 2013, 08:23:41 AM »
Like Brett said.  We want the airplanes to be pretty, so we'll get more appearance points and so -- to whatever extent it may make a difference -- we convince the judges that we're serious.

And, we think that's going to have more effect on our score than having something that's better aerodynamically.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Online Brett Buck

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Re: Why do we have shiny finished?
« Reply #4 on: July 27, 2013, 12:00:46 PM »
Like Brett said.  We want the airplanes to be pretty, so we'll get more appearance points and so -- to whatever extent it may make a difference -- we convince the judges that we're serious.

And, we think that's going to have more effect on our score than having something that's better aerodynamically.

   The aerodynamics are something we can deal with. My airplane had a classic mirror finish in 2006 (having been mirrorized a few days before the contest) and it flew and flies just fine. This "mirror finish" problem is not really much of a problem.

      Brett


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