1/24 Apollo/Saturn V (enlarged 1/48 Greelt et al version)

[Algebraist]

Dear all

The the 3D printed astronauts have had their overnight soak. I then left them to stand on kitchen roll for over a day. It took this long for them to stop leeching out water. Here is the result



Here are some close-up photos




As you can see the models still need to have all the "flash" removed but you can see all the support material is gone.

So after they have been cleaned up they just need painting. Will let you see how that comes out

Regards

Kevin

[Algebraist]

Dear all

So I have moved onto the interstage between stages 2 and 3.The only parts to be added here are some sway markers and the fairings for the four retro motors.

However I tried a very risky test of putting stage three on top of the interstage which is only one sheet of 250 gsm thick and no other support whatsoever



As you can see it held but if the cone was to buckle even slightly it would collapse completely. But what does this matter since I cannot stack the rocket vertically? Well I think I have found a place where I can stack the rocket vertically, just once and for a short time, but long enough to get some photos of it like that.

So I have decided to to strengthen the interstage so that it can easily support the rest of the rocket. Even though I say so myself, I think it would be nice for the model to be vertical at least once in its life (even though it will not be for very long).

The inside of the stage 2 stage 3 interstage can be seen in this video (from 31 seconds



There is no way I could replicate this so I will just try for a functional "essence" of the inside (of course it would be nice to have a "Greelt" standard interstage!)

I settled on 8 "vertical struts". Using a bit of trig gives the slope of the cone as 16 degrees off the vertical. I decided to make each strut from 3 layers of 3 mm grey board for maximum strength. So here is one part and then all 24 parts



And then they glued into the 8 struts



I then gave then a quick "friction fit" try out



They were a good fit and take any load placed on the interstage.

Next were the circular segment struts. These will not be taking any weight (so are not needed from a structural point of view) but do stop any flexing of the wall of the interstage. For this reason I decided on two such rings each 1/3 from the top and bottom of the interstage. A bit more trig gave me the radius if the lower ring (190 mm) and upper ring (167 mm).

I decided to make each ring from two layers of corrugated card board. This required using the monster circle cutter and making sure I cut both the inner and outer radii with no "walking" by the cutter. So I used several pieces of sellotape for the point of the cutter to go into. Here are a couple of photos showing what I mean



So I managed to cut out my 4 circles, glue them together to make 2 circles and then cut them each into 8th's



So next will be to cover them in white card, trim them to fit and then glue them to the model

Regards


Kevin

[Algebraist]

Dear all

The the arrival of the model astronauts I got a little side tracked thinking about the bits of the model they would have inhabited.

It had always bugged me that I had glued the commanders window in at the wrong orientation in the boost protection cover. So the other day I hacked it out and put a new on in correctly



I feel much happier now but I doubt if anyone would have ever noticed.

Next I got to thinking about the LM. From an earlier post you will see that I have already built the LM that comes as part of this model. However it is in "landing" configuration. So its legs are splayed out. I kept thinking it would be nice to be able to have it as it was inside the SLA , with its legs folded in (as shown by this NASA diagram)



I looked at trying to adapt the model so the legs could fold in and out but could not manage it. So in the end I decided to make a second fixed "in flight" LM.

There were only three changes to make to the model as supplied. So I made the base



So the first change was I adapted the legs by cutting them so they could fold in and then shortening some cross struts to hold them in place



Here is what an adapted leg looks like



Because the feet of the LM will be folded in I thought it best to be able to separate the ascent and decent stages for storage reasons. So the second change was to join these two parts with magnetic paper



The third change was to glue the LM's feet at an angle



So here are some views of the finished LM along with SLA



Since the ascent stage is detachable I thought I would do one photo with the astronauts



Think this picture shows just how small the "living area" of the LM was. It is pretty amazing to think this tiny little box rose from the moon a quarter of a million miles from earth and kept the two people inside it alive

Regards

Kevin

[rifleman]

you have done an outstanding job from the start and kept it going bl##dy well done

[Ekuth]

Agreed- stunning build. I see you're discovering the same issues I had when I decided to start building uberbig models- support.

What may work with paper on a small scale doesn't work when you get beyond a foot or two... I can tell you from experience that foam core board can be your friend.

You've come up with some excellent solutions that are organic to the project, so good on you!

[Algebraist]

Originally Posted by rifleman

you have done an outstanding job from the start and kept it going bl##dy well done

Glad you are still enjoying it rifleman

Regards

Kevin

[Algebraist]

Originally Posted by Ekuth

Agreed- stunning build. I see you're discovering the same issues I had when I decided to start building uberbig models- support.

What may work with paper on a small scale doesn't work when you get beyond a foot or two... I can tell you from experience that foam core board can be your friend.

You've come up with some excellent solutions that are organic to the project, so good on you!

Thanks for the tip on foam board Ekuth.

You are right that internal structure "challenges" are a big part of a model like this. However I have found it is really good fun figuring out how to tackle them (when it works!) and (for me) has made the project even more enjoyable.

Many thanks for your compliments

Regards

Kevin

[Algebraist]

Dear all

As I have been working on the most recent bits of the model it struck me there is a nice connection between making the model and space travel which is conic sections

The trickiest thing to work out (mathematically) are the curves needed when a tube/pipe joins a wall etc. These form "conic sections" at the end of the pipe (like when doing the ullage rocket motors of stage 3)



(above picture from https://www.ck12.org/book/CK-12-Alge.../section/10.0/)

So particularly in a rocket it is mostly conic sections that make it up.

Amazingly (to me anyway) due to the fact that the force of gravity is described by an "inverse square law" (ie the force varies by 1 divided by the square of the distance between the objects) as stated by Issac Newton, this forces all space travel to be along the path of a conic section. Just for the record orbits have to be ellipses or circular (mathematically a circle is an ellipse of eccentricity 1), "swing by" paths are parabolas (like comets) which will never return, "sling shots" paths are hyperbola (used for "gravity assist" speed ups of satellites/probes into the solar system many of which people build models of in this forum).

Now to see the moon and other things in space 3D versions of the conic sections are used for the reflectors.

The Lovell radio telescope at Jodrell Bank in the UK has a parabolic dish



And a close up



The Hubble space telescope has hyperbolic mirrors



(from https://www.nasa.gov/mission_pages/h...ory/index.html)

And the Arecibo bowl is a spherical dish



(from https://www.space.com/20984-arecibo-observatory.html)

Finally (and maybe my favourite) is in order to practice getting to the moon parabolic flight was used simulate weightlessness. In order to achieve this you fly a particular parabolic path on a plane like this



Now watch the video from 3.00



And here is a great video of zero G experience



What an experience that must be. All thanks to the mathematics of the conic sections!

Regards

Kevin

[dhanners]

If anybody offered an Airbus A300 model (and I'm not sure anyone does...) that would be a cool repaint.

[Algebraist]

Oh yes, great idea David.

Perhaps also SOFIA (jumbo) and the Shuttle carrier. I wonder if either of these is available in paper, does anyone know?



(from NASA's newest telescope is housed in a special jumbo jet that flies at 45,000 feet - ExtremeTech)



(From https://hub.united.com/tricked-out-747s-2508103068.html)

And here is a possible project of two USA icons



(From https://hub.united.com/tricked-out-747s-2508103068.html)

Regards

Kevin