Indoor weights,/ was: PPP-film

From: Mark F1diddler <f1diddler_at_yahoo.com>
Date: Mon, 19 Sep 2011 17:24:33 -0000

--- In Indoor_Construction_at_yahoogroups.com, themaxout@... wrote:
>
> I've been following this thread about covering and the weights, etc. I
> have data from somewhere in the past that says the 1 micron stuff weighed
> .0008 gms/in-2. That would imply that .6 micron covering would weigh
> .0008*.6=.00048. That seems like a big difference.


Rick,
Sounds about right, except the above weight is in line with my 2004 Y2K, which they always called ".5 micron", and also the reason I use the term *nominal* thickness--our "specs" lore is apparently not so accurate. Whose fault, I don't know. I do know that our weights table (Files) is pretty well vetted by indoorists, although a couple have reported anomalies in their own materials.
  
> >
> Then I was thinking that a typical EZB is about 75 in-2 on the outside and
> the difference is 75 * (.0008-.00048) = .024 gms. Is that killer
> penalty? The sketch I saw of Kang's EZB has the model at .374 gms for the model.

Okay, I see it as 55-56 sq." for wing, non-projected, +27 sq" for 50% stab, +3-4 sq" fin,= 86 sq". Available OS film at .053g/100sq" =.046 gram of film. Adhesive, 7 mg or UP, probably. So, .053 g complete covering job with OS film, if all goes well. 2 or 3 mg less with 2004-run Y2K.


>
> .but the .024 grams seems like humidity on the wings can be more than that,
> or even the tag ends of the rubber knot.

Can't speak for humidity weight, but (I'm on a roll!) tag ends for a .033" loop ezb motor should be less than 2 mg. On second thought, I do know that if my F1d picked up an unaccountable 24 milligrams in different weather, I would be upset. (The *accountable* weight gains are bad enough....)

>
> And, how do you guys build that light?>>

IMHO, just light wood cut to correct sizes. All the rest is often overstated (ie, glue weight) at least once you're in ballpark range. For example, consider that Larry Cozlick's F1L glue weight calculation for F1L is .031 g. So suppose someone gets sloppy and uses 100% more than that--- only 31 mg over on glue...no deal breaker by itself.
Mark B
Received on Mon Sep 19 2011 - 10:24:35 CEST