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#2040 by roma847 on 14 May, 2021 16:39
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Hello everybody,
but now one also needs 16 Gear cases on which the 16 Propel motors are mounted,
Source: Jürgen Ziegler (FADDA) - YouTube
which one can see here after assembly.
Source: Jürgen Ziegler (FADDA) - YouTube
Therefore maybe you can imagine that I'm not really bent on scratching 16 exemplars of this tricky assembly, especially since they are only about half the size in my scale 1/160, and that I can't make friends with David Maier's less detailed kit variant anyway.
Source: papermodelers.com (mk311049)
Source: papermodelers.com (mk311049)
That's why I have asked my ARC friend Joe (crackerjazz), who has kindly started with the 3D modeling of the Propel Motors,
for which I've emailed him some first dimensions. 
Source: Micro Artwork, Mischa Klement (cyana)
Unfortunately I don't have any NASA drawings of these assemblies. But meanwhile I'm able to take measurements (1/160) in Mischa Klement's Truck 3D PDF, because the determination of the dimensions from the paper kit is rather imprecise. 
Source: Micro Artwork, Mischa Klement (cyana)
And always with Hi-Res photos of the original in mind,
Source: NASA
we are slowly progressing, step by step, as one can see in this progress shot.
Source: ARC Forums member Crackerjazz
It can carry on like this.
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#2041 by roma847 on 14 May, 2021 22:51
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Hello everybody,
here comes the next progress with some more details.
Source: ARC Forums member Crackerjazz
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#2042 by Starbase101 on 14 May, 2021 23:03
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I will have to ask him if I can buy in 1/144 scale, as I did with his sprocket model. (My MLP and crawler will be 1/144 to match the shuttle stack.)
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#2043 by roma847 on 15 May, 2021 23:43
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Hi Mike,
I'll already warn Joe in advance!
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#2044 by roma847 on 18 May, 2021 22:00
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Hello everybody,
during my intensive occupation both with Mischa Klement's Crawler Kit and with his ingenious Truck 3D PDF, especially during determining various dimensions with the 3D measuring tool I came across something that gave me a bit of a headache.
And those are the sometimes minimal thicknesses of certain parts in the tenths of a millimeter range, with which Shapeways should have considerable problems during printing, without knowing their latest limit values. 
Such a thin part I want to show using the example of the retaining plate (part 5), which only is approx. 0,1 mm thick, to which the holders of the brake shoes of the brake disc (parts 9/10) are attached.
Source: Micro Artwork, Mischa Klement (cyana)
Similar parts with critical wall thicknesses I have framed in red in the Outlines PDF, whereby it is, among other things, the motor feet (parts 18-22),
Source: Micro Artwork, Mischa Klement (cyana)
which one can locate in the assembly instructions using the overview of the individual parts of a left Propel motor, which I always have within reach.
Source: Micro Artwork, Mischa Klement (cyana)
For illustration the proportions of the parts and distances that always appear huge in the 3D model shots, in the following picture I have determined the distance between the brake disc and this retaining plate, which is only approx. 1 mm.
Source: Micro Artwork, Mischa Klement (cyana)
About this issue of minimal thicknesses I've informed my 3D modeler and asked him how we should deal with it.
Thereupon he has said that once the 3D model is ready, we might have to adjust the thicknesses and enlarge small details, because otherwise they would be invisible.
This is undoubtedly an advantage of Paper models, which Mischa Klement was able to use in his paper kit, since thin components made of paper still have sufficient stability. From this point of view, paper allows much smaller thicknesses than 3D printing, in which it may no longer be printable, which must be taken into account when 3D modeling.
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#2045 by Starbase101 on 18 May, 2021 22:05
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Does everything on the model need to be 3D printed? Why not simply leave the thin parts off the model and make them with custom photoetched brass (easy enough to do at home)?
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#2046 by EG on 18 May, 2021 22:16
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This is undoubtedly an advantage of Paper models, which Mischa Klement was able to use in his paper kit, since thin components made of paper still have sufficient stability. From this point of view, paper allows much smaller thicknesses than 3D printing, in which it may no longer be printable, which must be taken into account when 3D modeling.
Brother, there is a technique the paper modelers use for just such issues... with the part in plain paper, (or even tissue paper) They infuse the part with thin superglue as a stiffener... When dry it becomes very stiff, easily paints, and looks the part of something very thin..... Far thinner than PE....
Looks to me like a perfect example of a situation where the technique would work wonders.... You can use various thickness's of paper to get the part thickness you need..... You can duplicate parts much thinner than 3D printing will allow this way....
.1mm = .004in, the thickness of thin printer paper
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#2047 by roma847 on 18 May, 2021 23:01
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Thanks for your well-meant tips, but the whole motor is so tiny that I don't want to fiddle around him with small CA reinforced paper parts.
Tomorrow I'll show you a scratched Propel motor for fun made of plastic, maybe then you'll understand my plan of giving this midget a chance with the help of 3D printing ...
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#2048 by Starbase101 on 18 May, 2021 23:03
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For a larger 1/144 version of the model, can you ask him to have the details closer to the correct thicknesses? Details which are too thin at your scale may be fine at the larger scale.
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#2049 by roma847 on 18 May, 2021 23:18
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Well roared, lion,
but you have to ask him for that yourself, you know him.
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#2050 by EG on 19 May, 2021 00:33
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Thanks for your well-meant tips,
Patiently waiting to see your solution my friend.....
I'm sure it will be brilliant..... -
#2051 by roma847 on 19 May, 2021 18:22
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About this I'm not sure ...
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#2052 by EG on 19 May, 2021 20:27
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About this I'm not sure ...
I have faith my friend.... If anyone can figure it out, you can.... -
#2053 by roma847 on 19 May, 2021 20:44
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my friend for your faith, but you need still wait for a while, because I still have to translate my post ...
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#2054 by roma847 on 19 May, 2021 23:51
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Hello everybody,
in order to finally get a real idea of the size of such a Propel Motor in my scale (1/160), I have tried just for the fun of it to scratch such a motor from plastic, and have quickly realized what a midget it is.
For the base body of the motor I've used an Evergreen profile 4,8 x 6,3 mm, which I've cut on the narrow side with the precision saw on approx. 5 mm.
Then I've drawn the octagonal shape of the motor housing onto the front side,
and afterwards I have filed down the four corners, whereby I had to be very careful not to take away too much. 
On this approx. 7 mm long octagonal base body I have glued on the two disks (part 3) for fixing the retaining plate (part 5) for mounting the brake shoes of the brake disc (parts 9/10).
Source: Micro Artwork, Mischa Klement (cyana)
Then it was the turn of the front brake disc shaft and the rear drive shaft.
For the retaining plate I've used Styrene 0,15 mm and for the brake disc Styrene 0,3 mm,
which were then glued, as well as the two rear ventilation openings (part 33) and the cable box (part 35) on the inside of the (left) motor. The ending was formed by the four small feet (parts 20-23) made of Styrene 0,15 mm, which were glued to the underside of the base body, wherewith I then wanted initially let it go at that. 
And there he lies now, the (unfinished) proud midget that I fiddled around with for a few hours,
the one with approx. 14 mm length has place on my Euro Cent coin,
and whose brake disc with Ø 5 mm, as already announced, stands comfortably on the globe of the coin.
Here one can see for comparison the original Propel motors in the older version, relevant for my STS-6 Crawler,
Source: Library of Congress (HAER FL-8-11-C-3)
as well as here after upgrading and modernization of the Crawler Transporters for the SLS Program, which can be easily recognized by the stronger blue brake shoes.
Source: NASA
Because I now know the amount of hand work involved in crafting one motor, I hope all the more that we can get right a printable 3D model for a Set of 16 + 2 reserve motors.
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#2055 by roma847 on 25 May, 2021 19:02
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Hello everybody,
since one can measure almost all parts in the Truck 3D PDF, I was curious and as an exercise I measured some other details in order to scratch them if necessary, or at least once to try what is still feasible in 1/160.
First of all there were these 4 legs (parts 18/19) discussed previously, which I've measured.
Source: Micro Artwork, Mischa Klement (cyana)
Source: Micro Artwork, Mischa Klement (cyana)
I've then printed out their outlines from the Outline PDF, then stuck them onto thin Evergreen Sheet Styrene (0,13 mm) and then cut them out, which due to the "Size" wasn't that easy.
And since these are angle profiles, I then folded them under a steel ruler, which was also pretty tricky.
Gluing the legs was rather fiddling, because I had to somehow hold the motor and be careful not to let these midgets jump out of the tweezers, but what I still succeeded in doing, what will still be seen.
Before that I still had measured these two flaps (parts 27) over the service openings,
Source: Micro Artwork, Mischa Klement (cyana)
which are each closed with a Tension lock, which should just about be printable, I hope at least.
Source: Micro Artwork, Mischa Klement (cyana)
Source: Micro Artwork, Mischa Klement (cyana)
In any case, that wasn't a hurdle for me.
On the left beside can be seen one of the four Transport eyelets (parts 30/31),
Source: Micro Artwork, Mischa Klement (cyana)
whose thickness in paper thickness (0,1 mm) should be probably too thin for Shapeways.
Source: Micro Artwork, Mischa Klement (cyana)
For these eyelets I used a flat U-profile (0,7 x 1,2 mm), from which I've cut off thin slices with the razor blade.
And then also to the cover cap between the eyelets and the small screws,
Source: ARC Forums (crackerjazz)
which I made from Evergreen Sheet Styrene (0,13 mm) with my Punch & Die Set with diameter Ø 0,8 mm and the smallest existing diameter Ø 0,6 mm, which however should only be half as large.
And then the most stressful action came with the gluing of these midgets,
which is one more reason for preferring to leave the 16 motors to 3D printing. 
As already said, the screws are too large and should only be approx. Ø 0,3 mm, which I've then cut off from a corresponding thin rod,
and tried to apply,
but with which I now stop trying to want sophisticate myself further.
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#2056 by roma847 on 26 May, 2021 11:13
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Hello friends,
while I was agonizing over this tiny motor, my ARC friend (crackerjazz) was busy modeling and has sent new progress shots with more details, which look great.
As one can see, he even got right the Toggle fastener on the Flaps over the service openings,
although some details, like this one, may need to be simplified or enlarged in order to be printed. 
These images all show the left Propel motor in different perspectives.
This also includes a right motor, since they are always arranged in pairs, as has already been seen several times.
Source: NASA
And this right motor is now also modeled, so the set is complete. Heart, what more do you want!
I have already thanked the creator warmly for this, who has really done a great job so far. 
However, I've noticed a little detail that I've told him with the request for correction.
And that concerns the two brake shoes, which have the same thickness in the present model, but of which the larger brake shoe is actually only half as thick as the smaller one, as one can see in these 3D PDF images and also in the original photo. The multiple layers in the paper kit always correspond to a paper thickness of approx. 0,1 mm. 
Source: Micro Artwork, Mischa Klement (cyana)
Source: Micro Artwork, Mischa Klement (cyana)
Therefore the Brake disc should only be approx. 0,2 mm , for which as a matter of prudence he has chosen 0,3 mm in his 3D model, as this is according to the Shapeways-Design Guidelines is the minimum wall thickness for a supported wall, which is connected at least on two sides of the wall, while an unsupported wall (minimum 0,6 mm!) is connected only on one side of the wall, which is why some parts, whose thickness in the model previously only corresponds to the paper thickness, still have to be modified.
Fortunately, the brake disc is connected on three places, namely with the drive shaft and with the two Brake shoe holders, which is why a thickness of 0,3 mm should be permissible in my opinion.
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#2057 by roma847 on 27 May, 2021 00:31
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Hello everybody,
in the meantime, my Ghostdesigner has also taken into account twice the thickness of the smaller brake shoes in his 3D model, wherewith the picture always more is rounding off itself.
And this is a look ahead to the later Propel Motor Set, which Shapeways could then print once the adjustments have been made. In addition, the connecting webs between the motor rows have to be modeled before the complete set can be uploaded to SW.
In these theoretical Sets of 16 motors the adjustment/enlargement of the details is not yet taken into account, but this will happen soon. In addition, in the final set, at least 2 reserve motors should be provided in order to have a backup.
Next I will turn to the Gear cases, of which, logically, 16 pieces are also required, which also is craving for 3D printing.
Source: Micro Artwork, Mischa Klement (cyana)
After all, the motor power has to come onto the Crawler chains and from there onto the Crawlerway.
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#2058 by roma847 on 30 May, 2021 21:08
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Hello everybody,
and how this was technically realized at the time on behalf of NASA is indeed an exciting thing that interested me in advance, as always.
The mere idea that the drive of these huge caterpillar tractors should be done by these comparatively measly Propel motors seemed a mystery to me at first, but what has now become clear to me.
Thereto here is a worthwhile look into the opened gear housing on the multi-stage gear consisting of 10 gears and 5 shafts after the dismantling of the front gear unit with the huge Drive Sprocket, on which the extension drive shaft of the dismantled Propel motor can be seen.
Source: forum.nasaspaceflight.com (JayP)
On its end sits a Propel pinion that engages in the dome-shaped attachment in a vertical Bevel gear, which can be seen very nicely on this overview drawing,
Source: NASA Technical Reports Server ( NTRS)
just like in this impressive 3D model by a crawler expert from the NSF Forum (JayP).
Source: forum.nasaspaceflight.com (JayP)
As was already be seen, this gear housing looks like this in the assembly instructions for Mischa Klement's Paper Kit.
Source: Micro Artwork, Mischa Klement (cyana)
In his Truck 3D PDF, after long and stressful trials of the Acrobat Reader measurement tool, I have now succeeded in determining several measurement results at the same time and in the picture instead of a single measurement to hold on.
And these are the individual parts of the gear case printed out from the Outlines PDFs,
which I then glued back onto thin Evergreen Sheet Styrene (0,3 mm).
And from these puzzle pieces I will now try to scratch the gearbox housing. Let's see if and how well I can manage that.
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#2059 by roma847 on 31 May, 2021 22:49
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Hello everybody,
before I try scratch-building the Gear case, I would like to briefly come back to the Propel motors and show an interesting video sequence in which one can see the relatively slow running engines,
Source: NASA's Kennedy Space Center
whereby I estimate that they run at a rotational speed of approx. 60 rpm.
BTW, this video is so interesting that it should be watched in full length.
