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Author Topic: Landing Gear and Bevington Object shadow study  (Read 12021 times)

Greg Daspit

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Re: Landing Gear and Bevington Object shadow study
« Reply #15 on: March 22, 2019, 09:20:01 AM »


It might be possible to get AutoDesk’s help building a model. Their CAD/CAM BUILD Space is in my building in Boston and they accept applications for protects to utilize it, I think for free if non-commercial. See https://www.autodeskbuildspace.com/

They have an amazing array of robotic fabrication tools that can work with a variety of materials. In this case we might want to use something easy like high density foam - I am not sure we could create a “working” model (with moving parts) without a lot of difficulty.

The BUILD Space studio has huge windows to the promenade and I have seen lots of fascinating projects fabricated there. I also notice that it is fairly underutilized and they appear to like projects that capture the imagination of passers-by.

I can reach out to them if you think it is worthwhile.

Alternately, it could be built on a standard 3-d printer but it would have to be a large one - most design firms like mine have printers that are too small, although the model could be scaled down and still work, I think.

Jon
I like the idea of foam as a medium for a large model.  The lighter the better because some system or a device ( like the adjustable arm to a lamp) would be needed to be able to make position adjustments. The fork has 4 different axis you need to align. Both the fork and worm gear assemblies need to be rotated about all axis as well as move vertically and horizontally in all directions. You would probably also need a monitor close to the model with a live feed from a video camera. The camera is too far away to go back and forth to check the image and make adjustments to positions.

As far as worthwhile doing this?  After doing close to a thousand rendering runs with the object in different positions I personally don’t think it’s needed. But some have asked me about an overlay and I think the large scale, real camera test might be the best way to do it.
 
I would caution to not get too much into modeling every detail because the distances involved don’t let you see them. At one point I considered buying a program from Autodesk that had attributes you could enter for both the Worm and the Worm Gear to model the teeth. This program is used to actually design worm drives. I finally decided to just make the teeth straight because you probably can’t tell they are enveloped (slightly curved) if you looked at them from 30’ away, much less from 300’ away.
3971R
 
« Last Edit: March 22, 2019, 12:00:30 PM by Greg Daspit »
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Ric Gillespie

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Re: Landing Gear and Bevington Object shadow study
« Reply #16 on: March 22, 2019, 09:25:58 AM »

Gentlemen,
This sounds like a fascinating project.  Its greatest value would be in demonstrating how convincingly the Bevington Object matches the wreckage of the Electra gear assembly.  Despite all the excellent work by Jeff Glickman and Greg Daspit, to many people the object in the photo is still just a blob.
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Leon R White

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Re: Landing Gear and Bevington Object shadow study
« Reply #17 on: March 22, 2019, 05:02:18 PM »

Greg, thank you for the recap of thinking so far on the arrival of the object.  Re: getting started with the model.  There is small plastic kit of the electra, configurable as AE's, that might serve as a starting place for some kinds of tests. However it is of typical small model scale. It does have gear tho it may be the later gear. But, there should be a number of TIGHARS that can build or modify a plastic kit landing gear.  I have said kit in storage.  Bigger scale and the autodesk work would be ideal as it could be 1:1 scale, of course.

Leon
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Ric Gillespie

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Re: Landing Gear and Bevington Object shadow study
« Reply #18 on: March 23, 2019, 07:30:54 AM »

There is small plastic kit of the electra, configurable as AE's, that might serve as a starting place for some kinds of tests. However it is of typical small model scale. It does have gear tho it may be the later gear.

I have the kit.  The gear has only the tire, wheel and strut and includes neither the bull gear nor the later knuckle mechanism.
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Leon R White

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Re: Landing Gear and Bevington Object shadow study
« Reply #19 on: March 30, 2019, 12:45:57 PM »

Great!  Now all we need is a TIGHAR to make a few parts out of plastic and we might have a replica - albeit very small.  Any takers?

Leon
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Ric Gillespie

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Re: Landing Gear and Bevington Object shadow study
« Reply #20 on: March 30, 2019, 01:42:19 PM »

I don't think such a tiny replica would be much use.
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Greg Daspit

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Re: Landing Gear and Bevington Object shadow study
« Reply #21 on: March 30, 2019, 02:01:21 PM »

A small scale model of the hard components of the landing gear would be easier to work with. My main concern is what would be the difference between a camera set at the closer scaled distance compared to Bevington’s camera?
A small scale model would also be easier to do a shadow study on a real model because you could model the deformed tire in clay.  (Autocad not good for this) All of this mounted to platform with sun dial to be adjustable to match azimuth and altitude learned from the Autocad study.
What’s needed to get it 3d Printed?
3971R
 
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Ric Gillespie

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Re: Landing Gear and Bevington Object shadow study
« Reply #22 on: March 31, 2019, 08:05:58 AM »

This is what the gear parts of the plastic model look like.  As you can see, the struts/forks are about 7/8 inch long. There is no bull gear. I'll be happy to send the model if it would be of any help. 
We have no 3D printing capability here at TIGHAR HQ.
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Greg Daspit

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Re: Landing Gear and Bevington Object shadow study
« Reply #23 on: April 01, 2019, 11:34:59 AM »

The BUILD Space studio has huge windows to the promenade and I have seen lots of fascinating projects fabricated there. I also notice that it is fairly underutilized and they appear to like projects that capture the imagination of passers-by.

I can reach out to them if you think it is worthwhile.

Alternately, it could be built on a standard 3-d printer but it would have to be a large one - most design firms like mine have printers that are too small, although the model could be scaled down and still work, I think.

Jon
Jon, I should have addressed my previous post to you since you might have access to 3D printers.

Do you know what would be needed to get a 3D printed model?
A 1:12 model would have the longest dimension of the model be about 3 ½” inches.  We could make the scale so it is slightly smaller but that seems like a workable size.
I don’t know about 3D printing but read that AutoCAD models can be used. It is better if they were modeled with solids. (I guess because the program tries to figure out how to carve an interior surface?)
Unfortunately the AutoCAD model I built has a lot of sections that are hollow (Hollow tubes for struts like the real components.) so it may not work.

Advantages to a scaled model method:
Can use real camera so you could do an overlay of an enlarged photo with the Bevington enlarged photo.
Small scale allows the tire to be formed more easily than in AutoCad (Using deformable material like clay). This would allow the study of the shadows instead of just angles of the fork.
Can do most of work indoors with single point light source before taking it outside.
A tilt table can allow the position to match the azimuth and altitude at Gardner on Oct 15 as long as the actual sun used when photographed is in reasonable position. See attachment:

A full scale study of just the hard components may also be done but that would need a big printer.
3971R
 
« Last Edit: April 01, 2019, 11:42:30 AM by Greg Daspit »
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Bill Mangus

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Re: Landing Gear and Bevington Object shadow study
« Reply #24 on: April 01, 2019, 02:34:20 PM »

I don't know if this will help the discussion but I'll throw it out for consideration.

The following is a link to a site which has for sale a 1/53 scale model of the Electra.  They say it's backordered but no delivery expected.

1/53 scale is an odd scale from the more normal and "standard" 1/32 and 1/48 scale plastic model aircraft.  I don't know if this is the same kit Ric has.

              https://www.scalehobbyist.com/catagories/Model_Aircraft/amelia-s-lockheed-10-electra/WIL00053598/product.php?kw=lockheed,electra

Here's a picture of the boxtop art:

              https://www.scalemates.com/products/img/2/5/4/951254-15126-75-pristine.jpg

Bill Mangus
Researcher #3054SP
 
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Ric Gillespie

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Re: Landing Gear and Bevington Object shadow study
« Reply #25 on: April 01, 2019, 02:37:15 PM »

Different box cover.  Same Williams Bros. model.
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Greg Daspit

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Re: Landing Gear and Bevington Object shadow study
« Reply #26 on: April 01, 2019, 04:09:49 PM »

Attached is an exhibit to show some examples for why the model needs to be more detailed than the kits.
 Some details like the diagonal angle on the worm gear are significant. At 12 noon it casts a shadow. At 1pm the protruding angle’s edge is in line with the angle of the sun so that it hardly cast any shadow. By 1:15 the angle is still not casting much of a shadow but the brake starts to cast a shadow. These images were part of the hard component study where the tire was removed to see if the hard components eliminated the landing gear as being the object.

The exhibit shows the main components needed.
I added the landing gear mounting bracket to a components needed since it may be under it and provides a point of contact for it to be sitting on a flat surface and not any part in a hole.

One other advantage to getting these 3D printed in full size is that divers on future expeditions can have real life mock ups on board to help with scale. It may help when looking at all that coral.
3971R
 
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Walter Runck

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Re: Landing Gear and Bevington Object shadow study
« Reply #27 on: April 04, 2019, 06:09:29 AM »

A couple of thoughts about a physical model of the gear:

1.  File format.  3D printing requires the source model(s) to be in a .slt or equivalent format (from stereolithography, the original technique where you selectively harden liquid goo by zapping it with a laser).  I can probably do the conversion from the native AutoCAD if you find a printer to use.  Most printers now use a filament that's melted at the tip as it's fed out.  Think weed eater line being passed through a small torch and dripping out in very small but well-placed drops.

2.  If you want a full size model, why not have a machine shop do one out of metal?  This stuff was designed for 1930's manufacturability, so it appears to be a weldment of mostly bar stock with some gussets and finished diameters.  I don't have the Lockheed drawing, but unless it was a forging, it would be a small project for a job shop or even a hobbyist with a saw, a lathe and a welding machine.  Even if it was a forging, we don't need the strength since we're just looking at geometry and possible deformations so a lightweight mockup would do. 

3.  Find a set of gear for sale or loan.  There was some lying around up in Alaska a few years ago as I recall.

Nice work on the shadowing study.  It is hard to follow how the components end up in the modeled positions from their as-built arrangement i.e. what bent or broke to hold them where they appear in the assumed position?  Is there a thread I missed that explains the thinking?
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Ric Gillespie

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Re: Landing Gear and Bevington Object shadow study
« Reply #28 on: April 04, 2019, 09:47:20 AM »

3.  Find a set of gear for sale or loan.  There was some lying around up in Alaska a few years ago as I recall.

Recovering anything from the Alaska wreck would be virtually impossible. Attached are photos from the wreck in Idaho.  You wouldn't believe how heavy this stuff is. Gotta be over a hundred pounds.   Recovering these pieces from the ravine would take a Jeep with a winch and about a quarter mile of cable. Then you'd have to figure out how to get them home. 

Nice work on the shadowing study.  It is hard to follow how the components end up in the modeled positions from their as-built arrangement i.e. what bent or broke to hold them where they appear in the assumed position?  Is there a thread I missed that explains the thinking?

In the Idaho crash, on one side, the oleo piston on the fork pulled out of the strut.  On the other gear, the assembly stayed together.
In the Luke Field crash, the shaft of the oleo piston broke. The worm gear on the upper strut twisted around and cut open the tire.
That appears similar to the disassembly implied by the Bevington Photo.
 
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Jon Romig

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Re: Landing Gear and Bevington Object shadow study
« Reply #29 on: April 05, 2019, 08:13:53 PM »

The BUILD Space studio has huge windows to the promenade and I have seen lots of fascinating projects fabricated there. I also notice that it is fairly underutilized and they appear to like projects that capture the imagination of passers-by.

I can reach out to them if you think it is worthwhile.

Jon
Jon, I should have addressed my previous post to you since you might have access to 3D printers.

Do you know what would be needed to get a 3D printed model?

I will talk to the folks at the Build Space on Monday.

Jon
Jon Romig 3562R
 
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