Yet another Space Shuttle

[Jeff Lassahn]

I've been building a lot of space shuttles recently. Here's another one:


It hasn't flown yet, when it stops raining I'll balance the orbiter so it glides and then launch the whole thing. Maybe plan on flight tests in early May.

Also, I know it would really benefit from decals. I'm going to work on those, too. There's a set from Tango Papa that could work but I'm planning to print up my own when I get around to it.

It's 1:200 scale, the external tank is a BT-60, solid boosters are BT-20s, expected to fly on a B or C engine.

Several of the more complicated parts, including the nose cones, the orbiter nose, and the engine details are 3D printed. That's worked out great, it allows a nicely detailed model without a huge build effort.

I have a bunch of photos of the build process somewhere, when I track them down I'll probably turn this into a detailed build thread.

 

[Jeff Lassahn]

How it all happened part 1: The orbiter

The bottom, wings, and tail are 1/8in balsa, some internal structure is 1/16in balsa, the shell of the body is 60lb cardstock, and the nose, OMS pods, and engines are 3D printed. Here's the parts cut and laid out:


The nose, tail and internal bulkheads are built up onto the bottom, then the cardstock is wrapped around that:

 

[Jeff Lassahn]

The wings are assembled from pieces, using a template to apply 15 degrees of up elevator.
I leave the two elevator pieces attached by a tab while gluing, then cut them apart, which seems slightly easier than gluing them separately.

Then the wings are glued to the body. I build this one with the wings flat, no dihedral angle. Initial glide testing suggests maybe a little angle would help with roll stability, but I'm hoping it's fine as is. Stay tuned for an actual test flight when I get a chance...

 

[Jeff Lassahn]

A bit of sanding is now needed to get everything to its final shape.
Where the bottom meets the nose, the balsa has been left slightly large, so it can be sanded to match the exact curve of the plastic nose. The nose has a lip at the front that the balsa butts up against which both aligns the parts properly and acts as a template for sanding a matching curve into the balsa.
The leading edges of the wings are given a rounded profile, and the trailing edges are tapered.

 

[Jeff Lassahn]

Now everything is painted, and the remaining parts are glued on.
Except for the nose tip which must be left loose until final glide testing so nose weight can be added as needed.
And two launch lug pieces will be glued to the bottom rear later as the interface to mount the orbiter on the rest of the stack.

The orbiter is by far the hardest part of the build, and it's actually no too bad. If someone gave me these parts as a kit I wouldn't be cursing their name while trying to build it.

 

[Jeff Lassahn]

Part 2: Solid Rocket Boosters

The parts are BT-20 tubes, 3D printed noses, skirts and mounting bits, and some Plastruct styrene rod.
There's not much to say construction-wise here. Mark a couple of reference lines and glue everything on.

I did later add four 3mm by 3mm 1/16in balsa pieces to act as standoffs between the SRBs and the External Tank.

 

[Jeff Lassahn]

Part 3: The External Tank

The parts are a BT-60 main tube, a BT-20 engine mount tube,
all the usual fiddly bits, launch lug, engine hook, engine block, kevlar and elastic, parachute to come later...
A lot of 3D printed parts.
The nose cone (in two parts)
The back end, which also aligns and supports the engine mount and provides a slightly hidden slot for the engine hook
The rear orbiter mount
The front orbiter mount and feed line details.
A cardstock wrap for the intertank details. More about this later...


I made a couple of design errors on the 3D parts. The back end and nose tenon diameters are too small by about 0.5mm so I shimmed them both with a couple of layers of cardstock. I also left off an attachment point in the back for the shock cord, so I drilled a hole and installed a little piece of 1/4in wooden dowel where the plastic crossbeam should be.

With those fixes, the shock cord and engine mount can be installed.

The end of the engine hook is just slightly inset relative to the longest point on the rear dome. I've also printed a plug with a small tab that can be inserted flush to cover all the engine stuff for display.

Then all the bits are glued onto the main body tube.

 

[Jeff Lassahn]

Interlude: Rant about the intertank wrap

I'm not happy with the cardstock wrap. For this build it's just a flat piece of card with no details or texture. It's better than nothing, but I really want something that better shows the texture of the stringers.

The original plan was to have the wrap be part of the 3D printed front mount and feed line details. I had the parts printed in Nylon using SLS which I was hoping would allow printing a very thin flexible layer with details. Nylon is strong and flexible enough to handle that geometry, but the printing process was not able to make the thin sheet reliably. The parts that successfully printed have excellent detail and good mechanical properties, but there are so many cracks and voids that it ended up being unusable and I had to cut the entire wrap away.


So I'm now thinking about other ways to get the detail I want.
Do I keep trying with 3D printing and mess with materials, methods and geometry?
Do I do something with embossed cardstock?
Laser engrave either cardstock or plastic sheet?
Something else entirely?
Give it up, this is objectively a pretty small detail on a pretty small model?

Grrr. It was _almost_ sooo cool.

 

[Jeff Lassahn]

Part 4: It won't fly without fins

The clear plastic fins are made from 1/32in impact modified acrylic sheet. Which is just like normal acrylic except they add something to it to make it less brittle and more flexible.
Cutting it requires a bit of practice, I has the best luck with scoring it carefully with a knife and bending it so it breaks on the score line.

It can be glued with Cyanoacrylate but the glue takes longer to set than it does with other materials.

The fins are glued into lengths of BT-5 tube. The SRB rear skirt pieces are printed so they properly align and friction fit an inserted BT-5 tube.

 

[Jeff Lassahn]

Final assembly

The orbiter needs a pair of 5mm long launch lug sections to connect it to the rear ET support (the orbiter front is supported by a small ring in the 3D printed nose section). To align these accurately I place them on the ET, apply a little glue to the outside, then place the orbiter on them in flight position and hold it while the glue sets.


Then more painting, glue the SRBs to the ET and it's basically done.

 

[Hobie1dog]

Thanks for the pictures

 

[gerbs4me]

Really cool, keep the build pics coming!

 

[Hobie1dog]

Wow You are a real modeler. Impressive.

 

[CoolRockets]

I've been building a lot of space shuttles recently. Here's another one:
View attachment 574369

It hasn't flown yet, when it stops raining I'll balance the orbiter so it glides and then launch the whole thing. Maybe plan on flight tests in early May.

Also, I know it would really benefit from decals. I'm going to work on those, too. There's a set from Tango Papa that could work but I'm planning to print up my own when I get around to it.

It's 1:200 scale, the external tank is a BT-60, solid boosters are BT-20s, expected to fly on a B or C engine.

Several of the more complicated parts, including the nose cones, the orbiter nose, and the engine details are 3D printed. That's worked out great, it allows a nicely detailed model without a huge build effort.

I have a bunch of photos of the build process somewhere, when I track them down I'll probably turn this into a detailed build thread.

Can you do a Burns shuttle next?

 

[Jeff Lassahn]

Can you do a Burns shuttle next?

I don't know about those. What's a Burns shuttle?

 

[CoolRockets]

I don't know about those. What's a Burns shuttle?

I meant a Buran shuttle, it’s the Soviet unions attempt on a space shuttle

 

[Jeff Lassahn]

Oh, yes of course. I've got some basic dimension drawings on Buran, so I could probably give it a shot one of these days. I think it's just different enough that there's no parts in common, so I probably need to start over from the beginning, but that's not necessarily a bad thing.

 

[JPalmer621]

For your ET wrap I have used 110# card stock. Then score it with either a ball point pen or a mechanical pencil with the lead retracted. After attaching to the ET you can add more details

 

[Bravo52]

Nice build. Looking forward to a flight report (and video ). The shuttle is still on my build bucket list so I really enjoy seeing everyone else's builds and learning as much as I can.

 

[CoolRockets]

Nice build. Looking forward to a flight report (and video ). The shuttle is still on my build bucket list so I really enjoy seeing everyone else's builds and learning as much as I can.

I agree

 

[CoolRockets]

Just an idea, top gear reliant Robin space shuttle

 

[Jeff Lassahn]

It finally flew yesterday. Basically it worked fine...

Sorry, no video because we had several false starts due to igniter & GSE problems, and I suck at pointing cellphones at things.

I flew it on a B6-4. It got off the pad just fine and was straight and stable going up, but it did the thing where it stopped at apogee and started back sliding for a second or so before ejection.
The prototype (https://www.rocketryforum.com/threads/quick-n-dirty-space-shuttle.163853/) flies great on a B6-4. So this thing is really feeling the extra weight from all the fiddly little plastic detail parts and the plastic fins.
It would probably be better on a B6-2 or a C6-3.

I had limited time and a limited selection of engines with me, so I wasn't able to try out other options this time. Maybe next time I get out to fly...

The orbiter glided in well enough to survive landing, but it came in pretty steep. It was hard to judge exactly what was happening there (trying to do too many things at once, can't try to get video, watch the booster come down and watch the orbiter come down at the same time) but I'm thinking I need a couple more degrees of up elevator. I might try the trick of heating the glue joints and bending them a bit.

Another random minor problem: I put the engine hook facing towards the center of the ET so it gets hidden in the bulge. It turns out I also really want to have the igniter come out that direction to make it easy to bring in the igniter clips from the back, but then the igniter lays across the end of the hook and shorts out. I had to put the igniter and clips on the other side where they sit directly under the orbiter, where there's way less space. It works, but maybe there's a more clever arrangement I can figure out...

 

[CoolRockets]

It finally flew yesterday. Basically it worked fine...

Sorry, no video because we had several false starts due to igniter & GSE problems, and I suck at pointing cellphones at things.

I flew it on a B6-4. It got off the pad just fine and was straight and stable going up, but it did the thing where it stopped at apogee and started back sliding for a second or so before ejection.
The prototype (https://www.rocketryforum.com/threads/quick-n-dirty-space-shuttle.163853/) flies great on a B6-4. So this thing is really feeling the extra weight from all the fiddly little plastic detail parts and the plastic fins.
It would probably be better on a B6-2 or a C6-3.

I had limited time and a limited selection of engines with me, so I wasn't able to try out other options this time. Maybe next time I get out to fly...

The orbiter glided in well enough to survive landing, but it came in pretty steep. It was hard to judge exactly what was happening there (trying to do too many things at once, can't try to get video, watch the booster come down and watch the orbiter come down at the same time) but I'm thinking I need a couple more degrees of up elevator. I might try the trick of heating the glue joints and bending them a bit.

Another random minor problem: I put the engine hook facing towards the center of the ET so it gets hidden in the bulge. It turns out I also really want to have the igniter come out that direction to make it easy to bring in the igniter clips from the back, but then the igniter lays across the end of the hook and shorts out. I had to put the igniter and clips on the other side where they sit directly under the orbiter, where there's way less space. It works, but maybe there's a more clever arrangement I can figure out...

That’s great! If it flew what’s an ultimate win!