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Author Topic: Taking a second look at the Plexiglas pieces - 2-3-V-2  (Read 58841 times)

Ted G Campbell

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #30 on: January 30, 2016, 08:13:14 PM »

Guys,
You will need to do two graphics - one inside and one out side - to get the true picture of the plate i.e. it also validates the thickness throughout.
Ted
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Neff Jacobs

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #31 on: January 30, 2016, 09:18:59 PM »

From what I can see of the drawing the chord is 12.8 inches.   The offset to the outside of the curve is 1.7 inches by scale, which by the middle ordinate method makes the radius 12.5 inches
Scale 3.25 inches up to 4.75 inches  1.46:1   and the chord becomes 18.7 inches and the offset 2.5 inches which makes the radius 18.1 inches.

Middle Ordinate method
Measure the chord of any curve in this case in inches it only matters the units are kept constant.
Measure the maximum offset to the top of the curve
0.5* the chord = b
offset = a
R=a+b^2/2*a

Bottom Line use a compass, string or piece of lath to inscribe a 12.5 inch circle and the curve should match the 1:1 drawing.
Use the same equipment to measure a 18.1 inch circle which should match a 1.46:1 blow up of the drawing. 

My best guess is a .16 inch offset on a 4.75 inch chord which is difficult to match to an 18.1 inch radius circle.

Neff
« Last Edit: January 30, 2016, 09:26:39 PM by Neff Jacobs »
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Frank Hajnal

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #32 on: January 30, 2016, 10:17:08 PM »

If Electra windows were designed to be curved along two perpendicular axes, then shouldn’t the Lockheed engineering drawing show both of those curves?  Does the Lockheed drawing in fact show both these curves?

You're right.  It should, but it doesn't. I must be remembering it wrong (it was 20 years ago). Apparently the curvature is not compound. I do clearly remember holding the artifact up to the edge of the borrowed window and laying the artifact on the surface of the window and getting a perfect match.

What is the radius of curvature of 2-3-v-2, measured along the edge as shown in the curvature.jpg photo?  It should be possible to measure this reasonably well without any fancy tools, shouldn't it?

I dunno.  How would you do that?

Ric,  I think what you need is a radius gauge (I tried inserting a url to a catalog listing for one, but the url contains a character the forum software doesn't like). Maybe you know somebody who can lend you one that will do the job?




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Ric Gillespie

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #33 on: January 31, 2016, 06:57:49 AM »

The copy of the Lockheed drawing shown in the second photo below, was used to demonstrate a curvature match with the artifact, but appears to have been significantly enlarged beyond actual size, evidently by approximately 150%, when compared directly to the known dimension of the artifact (approx. 4.75”).

I don't understand how you decided that the drawing was significantly enlarged.  As far as I know, it was a 1:1 copy of a portion of the original drawing.
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Ric Gillespie

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #34 on: January 31, 2016, 07:07:49 AM »

This is getting a bit ridiculous. We did a good empirical study using the engineering drawing and an actual Lockheed 10 window and found them to be a match with the artifact. I see no reason to think that work was flawed.
We did not then claim, and we do not now claim, that it proves anything other than that the artifact and the Lockheed part appear to be made of the same material and have some of the same physical features.  Maybe the plexi is from NR16020. Maybe it's not. But it doesn't make sense to spend further time and resources nitpicking it.
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Neff Jacobs

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #35 on: January 31, 2016, 04:59:02 PM »

Ric,
I most respectively request you will reconsider. 2-3-V-2 is a unique Tighar artifact in that it has a single in or out criteria.   Unlike the post lost signals were someone long ago decided which were credible or incredible.  2-2-V-1 which you have described among other things as an IQ test or Jeff Glickman's photo analysis which we have agreed sometimes requires considerable skill in the art to understand.  The in or out criteria  for 2-3-V-2  is radius.    Dick Janson has favored us by expressing his concerns that the artifact is appearently being compared at 1.5:1 here.   Surely it is worth a little time to rule in or out the one and only artifact we have, that I know of, that has a simple in or out cartiera.
Neff
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Monty Fowler

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #36 on: January 31, 2016, 05:58:52 PM »

But it doesn't make sense to spend further time and resources nitpicking it.

By the same extension, then, it doesn't make sense to continue discussing anything else TIGHAR has found on Niku, does it?

I originally expressed enthusiasm for going full court press on 2-3-V-2 because I believe that if it did come from Amelia's Electra, it could be a diagnostic artifact. The fact that there is apparently no surviving paperwork proving that 1/8-inch Plexiglas was installed in the Electra means, to me, that it's veracity can always be questioned. You can imply all you want, and TIGHAR has liberally and repeatedly done that with this artifact, but at the end of the day it appears there is no realistic way to use it the way that I had hoped to.

Which is unfortunate.

LTM,
Monty Fowler, TIGHAR No. 2189 EC
Ex-TIGHAR member No. 2189 E C R SP, 1998-2016
 
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Steve Treadwell

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #37 on: January 31, 2016, 08:03:08 PM »


Middle Ordinate method
Measure the chord of any curve in this case in inches it only matters the units are kept constant.
Measure the maximum offset to the top of the curve
0.5* the chord = b
offset = a
R=a+b^2/2*a



Not that it really matters at this point, but I did come up with a different formula for the above:
R = (a^2 + b^2)/2a

Derivation:
from the drawing, R = x+a and R^2 = x^2 + b^2
from the first equation, x = R-a and substituting this into the second equation,
R^2 = (R-a)^2 + b^2
R^2 = R^2 -2aR +a^2 + b^2
2aR = a^2 + b^2
R = (a^2 + b^2)/2a
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Ric Gillespie

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #38 on: February 01, 2016, 10:42:55 AM »

Dick Janson has favored us by expressing his concerns that the artifact is appearently being compared at 1.5:1 here.   Surely it is worth a little time to rule in or out the one and only artifact we have, that I know of, that has a simple in or out cartiera.

I did as you requested and spent more than a little time trying to figure out how to double-check the initial analysis of the artifact.  We no longer have access to a Lockheed 10 window so I can't duplicate that comparison.  I agree with the need to make sure that the comparison of the curvature of the artifact with the curvature on the Lockheed engineering drawing needs to be at a 1:1 scale. The problem is, the paper drawings, if they still exist, are not accessible.  The best we can do is a photocopy made from microfilm of the drawings at the NASM Archive, but how do we make sure we're looking at a 1:1 print out?  I reasoned that if I scaled the curvature cross-section on the drawing to a 1/8th inch thickness for the plexiglas, the drawing would, by definition, be at 1:1 scale.  I did that and then compared the curvature of the artifact to the curvature on the drawing by overlaying the artifact on the scaled 1:1 drawing.  The results are shown below.

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Greg Daspit

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #39 on: February 01, 2016, 11:40:37 AM »

There appears to be a dimension of 22-11/16" at the top.  I cant read the others but am using just a I-phone. If a print of the film measures the same it is 1=1. Larger dimensions are better when checking scale. If it is not to scale, the image can be rescaled in Autocad and printed to any scale including 1:1. I can do this if there are readable numbers. There is always some distortion when checking other numbers after doing this, but not much. If the copy you start with has been thru a roller type printer , it will be distorted more between two 90 degree axis, but not much.
3971R
 
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Greg Daspit

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #40 on: February 01, 2016, 12:12:33 PM »

Using AutoCAD I scaled the image using the largest dimension I could read at (22 11/16"). After this, the dimensions on the right all dimensioned to 1" except the bottom one. Two different scaled drawings are attached.
3971R
 
« Last Edit: February 01, 2016, 12:27:15 PM by Greg Daspit »
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Patrick Dickson

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #41 on: February 01, 2016, 01:05:50 PM »

it looks like a match to me Greg, 1:1
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Neff Jacobs

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #42 on: February 01, 2016, 01:46:22 PM »

The 4.75 inch piece appears to span 3.25 inches on the drawing.

If I scale using the marked 1 inch increments as a reference:
The line width  is .070
Depending on where on the line I choose to do my scaling
Centre to centre an eight inch = .161
inside to inside .060
outside to outside .22.
.125 somewhere between 1.76:1 and .48:1

May I suggest placing the 4.75 inch piece along the curve so that it spans 4.75 of the one inch lines?
Neff.
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Ric Gillespie

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #43 on: February 01, 2016, 01:56:46 PM »

May I suggest placing the 4.75 inch piece along the curve so that it spans 4.75 of the one inch lines?

Neff, look at the artifact. The shape of the piece won't let me do that.  I used the longest stretch available (that top edge).
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Greg Daspit

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Re: Taking a second look at the Plexiglas pieces - 2-3-V-2
« Reply #44 on: February 01, 2016, 02:55:32 PM »

May I suggest placing the 4.75 inch piece along the curve so that it spans 4.75 of the one inch lines?

Neff, look at the artifact. The shape of the piece won't let me do that.  I used the longest stretch available (that top edge).

A possible experiment
Print the 1:1 drawing to “actual size”.  Make sure the printer is not set to “fit” or something else by checking the dimensions after.
Spray mount the 1:1 drawing to cardboard or foam core.
With an exacto knife cut a slot along the curves that is longer than the full length of the artifact.  The problem may be the drawn curve is not that smooth in places from what I could tell, so the slot could be cut a hair or up to 1/16" wider than 1/8” to not damage it and allow for the un smoothness of the drawn curve.
See if artifact passes thru the slot. Any gaps because the slot was wider can be observed to see any differences in curvature.
.
3971R
 
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