Build thread: fantasy scale Virgin Orbit LauncherX

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mbeels

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Everything is clearly marked so I can't possibly make a mistake.
Remember how I said up top that I labeled everything on the marking guide so I couldn't get anything wrong? That's called "foreshadowing".
I totally picked up on that. Good catch, especially while the glue was still wet.
 

neil_w

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WING ASSEMBLY

Multi-piece fin assemblies seem to be the norm for my builds, and this one is no different. First, six identical(-ish) strake pieces were cut.
wings - 1.jpg

Next, a piece is cut out of the middle of two of the strakes to fit the (papered, natch) wings.
wings - 2.jpg

Dry fit is verified...
wings - 3.jpg

...and then everything is glued and clamped:
wings - 4.jpg

wings - 5.jpg

CWF was applied to the exposed wood on the strakes and sanded. It didn't seem like a good time to paper.
wings - 6.jpg

For mounting, the underside of the assembly was hollowed out just a bit with sandpaper wrapped around a spend D motor:
wings - 7.jpg

It is nowhere close to a perfect fit on the BT-70, but it'll help the assembly sit more stably on the body when gluing, and also yield more contact area.
 

jqavins

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Definitely adding "Three Layer Shroud" to my list of band names, into a special category "Names that almost no one will understand". ;)
You have a list of band names? You're welcome to mine, if you want it: Tin Whiskers.

Anyway, I've only read through post #26, and I have a couple of questions.
BODY TUBE ASSEMBLY

With the fin can finished, it's time to start assembling the body tubes... Glue is applied, and the BT60 is slid into place.
View attachment 459475
Why does the BT60 not go all the way to the lower BT70 mounting ring? Is there a purpose to that gap?
SHOCK CORD FIX

You can see that the Kevlar loop ends about 1/2" from the edge of the body tube, which is perfect. When I pulled it out the back of the rocket...
View attachment 459692
Confused, I am. Why does the loop come out of the nozzle?
 

neil_w

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You have a list of band names?
Figuratively speaking, yes. Doesn't everyone?
Why does the BT60 not go all the way to the lower BT70 mounting ring? Is there a purpose to that gap?
Where the two tubes join is arbitrary. Moving it forward pulls CG forward a bit and reduces the ejection charge volume. In hindsight, I should probably have pulled it farther forward, although then it would have caused me problems regarding your next question below.
Confused, I am. Why does the loop come out of the nozzle?
The Kevlar length is set so that it stops short of the end of the body tube, to avoid zippers. This makes it hard (not impossible, depending on the BT size, but hard) to attach the elastic. By pulling the Kevlar out the back, it's easy to attach the elastic, then you feed the whole thing back into the rocket. Also convenient when you need to replace the elastic.

How well this works depends on how close the Kevlar attachment is to the center of the rocket. If it's at the center or forward, it wont be long enough to pull out back. This has happened to me on at least two rockets. And so it turns out that my location for the join between the motor mount and the BT60 was just right, by pure luck.
 

neil_w

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Caught up now.Really? Based on the picture, it seems like you do. And there you have it.
No, not really. Way too much repetitive work, inconsistent results.

I've been reading @hcmbanjo 's blog entries about shrouds, and he says to burnish the large end of the shroud with a sharpie while the glue is wet. I'll have to try that in the future, although I don't think it would have helped much with my very heavy and reinforced double-layer shrouds on this build.
 

neil_w

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ATTACHING THE WINGS

Good golly, we're almost fully assembled here.

A bead of glue is applied to the wing root, and down it goes, centered between the two lines:
wing attachment - 1.jpeg

Really, centering between lines the easiest and surest way to position fins when you don't have TTW slots to guide you.

Quick and Thick fillet follows on each side. Contrary to my usual practice, I didn't bother with the first TBII fillet to seal the joint. There's enough surface area on the 3/8" thick root joint that this thing isn't going anywhere.
wing attachment - 2.jpeg

Repeat for wing #2, and the assembly is completed:
assembly completed.jpeg

We still need to talk about that nose cone.
 

jqavins

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That was almost disappointingly simple. Anticlimactic.

Nice work, as usual.
 

neil_w

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NOSE CONE

BMS didn't have quite the stubby ogive nose I was looking for; @cwbullet kindly offered to print me one out of PETG. Here's how it looked when I got it (actually I might have already hit it with a bit of sandpaper before I took this picture):
Nose - 1.jpg

Very clean, but with the usual surface you expect from FDM printing. And so I started by attacking it with sandpaper. And let me tell you it sands like rock. Eventually I stopped sanding at this stage, exhausted:
Nose - 2.jpg

Then came a series of not-particularly-well-thought-out steps to smooth it. First, CWF:
Nose - 3.jpg

Even though we don't normally expect CWF to adhere well to plastic, in this case I figured that the extremely porous and textured surface would give it plenty to grab onto. After sanding, I wiped on thin CA to harden it up (the CWF that is), and sanded again. The result feels pretty good. There is some imperfection around the base...
Nose - 4.jpg

...where maybe the CWF didn't completely adhere or something like that. But overall it seemed good. As far as I can tell there is no exposed PETG at all (it's all covered by CWF and/or CA) so I'm hoping there will be no paint adhesion issues.

I measured the mass and CG of the rocket (still minus shock cord and parachute), and found it to be a bit lighter than expected (surprising) but also with the CG about an inch further back than I expected. I calculated if I could get about 1/4 ounce of weight towards the front of the nose it would do the trick. No problem, I'll just drill a hole and snake some clay into there. So I drilled me hole and...
Nose - 5.jpeg

... I had forgotten that the nose is not hollow at all, but there's plenty of infill in there. And so, clay was out. Instead, I decided that if I could pour some slow-cure epoxy into there, and it would eventually (?) flow to the tip, although I'd have no way to verify. And so, I mixed up my largest batch of epoxy ever (.28 oz; hey I'm an LPR guy) and poured it in, *slowly*. Much like refilling a liquid soap dispenser, it would periodically overflow, and I'd have to wipe it up and wait for it to seep downwards. When I was finished pouring, and waited a bit, I was very happy to see that it indeed had all flowed down... low enough that I couldn't see it, at least.
Nose - 6.jpeg

You can see that it has coated the material in the hole, but hasn't pooled there at all. Ultimately I seem to have added between .2 and .25 oz weight to it, and CG moved forward about 0.75", which I think is enough.

And *now* construction is complete.
 
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cwbullet

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Heck, if you send me a weight, I wound have printed the weight in it.
 

neil_w

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Heck, if you send me a weight, I wound have printed the weight in it.
I didn't think it would be necessary on this rocket. Live and learn! :)

An interesting possibility, though, might be to include some sort of hollow center core in the design, to allow for addition of clay or lead shot or whatever later on. But this seems to have worked out fine. Looks like I could pour some more in there if needed, too. I wish it were transparent so I could see exactly where the epoxy went. :)
 

jqavins

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I've mentioned before, heating clay so it settes into the tip lf a nose cone. I wonder if it could be heated enough to be pourable and still be good when it cools.
 

neil_w

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I've mentioned before, heating clay so it settes into the tip lf a nose cone. I wonder if it could be heated enough to be pourable and still be good when it cools.
I doubt it could be made sufficiently liquidy to have flowed (flown?) into that mess, but I dunno. If it could, what would be the advantage over epoxy? I guess it's cheaper, not sure about the density.
 

neil_w

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PRIMER

Opportunity and good weather coincided to enable me to shoot Rusto Filler/Primer on the rocket this weekend. I decided to try spraying the fully assembled rocket this time to see how it goes. It is less spraying work this way, in exchange for more effort at sanding. For me that is a good trade.
primer - 1.jpeg

I did not get a particularly thick layer on, but that's OK (I went right to the end of the can, and didn't feel like starting the next one).

Let's have a look at a few interesting spots.

One of the fins:
primer - 2.jpeg

Whenever spraying, I almost *always* find spots that I didn't cover fully. Fortunately, the papered fin is not particularly important for the filler primer. I'll just need to be very gentle sanding (probably start and end with 800 grit).

Let's see how my various seams came out, recognizing that they'll look a big better after sanding. Following pics have been edited to highlight the textures. Here's the seam in the nozzle shroud, and the joint with the tail cone.
primer - 3.jpeg

Here's the seam in the front transition shroud.
primer - 4.jpeg

Small bit of exposed seam in the tail cone shroud, in front of the fin:
primer - 5.jpeg

Seam between BT70 and front shroud (I didn't try too hard on this one because there will be a strip decal right up against it):
primer - 6.jpeg

Seam between BT70 and tail cone shroud:
primer - 7.jpeg

This shows that I most certainly have *not* figured out how to deal with the various shroud seams, given the ridiculous amount of time I put into them and the incredible degree to which they are still quite visible. They'll all look fine in the end, but the point is this is not what I am hoping to see after all the work I put in.

I'm particularly mystified about the seams in the shrouds themselves. I could swear those were much smoother before priming than those pictures show. I have had a similar issue when very long fins have forced me to have joints in the label paper; even though I feel like I have them perfect, after painting there is a quite visible seam. I'm a little puzzled by it all, although again the end result here will be fine.

I'll bring the rocket in from the shed sometime during the upcoming week. In the meantime, I'll work on the decals.
 

jqavins

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I doubt it could be made sufficiently liquidy to have flowed (flown?) into that mess, but I dunno. If it could, what would be the advantage over epoxy? I guess it's cheaper, not sure about the density.
No particular advantage that I can see really. Just musing.
 

neil_w

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SANDING PRIMER

I sanded down the rocket. I'm getting better at it: start with 220, *gentle*, and sand only until what's underneath just starts to show through (especially careful on papered fins). Finish with 400.

Sanding the fully assembled rocket wasn't too bad, given that it's large enough to be easy to work with, and I was happy to leave some primer on there.

Then, I look for any spot where the primer was fully removed, usually edges of fins or seams in the airframe (note I sanded a bit more than I wanted to in the front portion of the body):
ku0ib1vlQdWN5npgfUQCPQ_thumb_1226d.jpg

Even though I don't think I scuffed the paper anywhere, all those spots get a wipe of thin CA and then a light finish sanding with 800 grit. Even if the paper is scuffed a bit, this hardens it and smooths it out. This is what I get when I *don't* do this:
8RH3tpf6TZSiGIXG1lpRaA_thumb_1226e.jpg

Yuck.

Weight before primer: 4.59 oz
Weight with unsanded primer: 4.9 oz
Weight after sanding primer: 4.79 oz

And so the filler/primer added .2 oz to this rocket, which has a pretty good amount of surface area. That's not bad. I didn't try to remove as much primer as I used to; I'm happy to leave a thin layer there to act as, you know, primer.

Finally: Rusto filler/primer is much maligned for clogging sandpaper. In my experience, 220 grit has absolutely no problem with it. 400 grit will fill up pretty fast, but when it does I just put it aside and grab a new piece. Afterwards, I run it under water and brush it off with a wire brush, and then it looks like this:
pDTGBMCQR6aSxXjQwdQC%w_thumb_1226c.jpg

The key, I think, is to stop using a piece of 400 grit paper once it fills up. Continue, and it'll eventually clog permanently in spots. There are trace amounts of primer left in that sandpaper, but it's got plenty of life ahead of it.

(Yes, that piece of 220 grit on the left is really old; I realized to my horror that it's my last piece, so I'm gonna hold onto it until I can run to HD and get a refill.)

Ready for white paint.
 

mbeels

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Looking really good. It seems like this rocket went together quite quickly! Looking forward to seeing it with artwork.
 

neil_w

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Looking really good. It seems like this rocket went together quite quickly! Looking forward to seeing it with artwork.
Almost certainly my fastest build thread, but only because all the parts prep was done a year ago. All I’m doing here is assembling and finishing.

Admittedly, my paint opportunities have come more quickly than usual.
 

neil_w

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Decals sheet is looking good. I did a better-than-usual job of clear-coating this time, it's smoother (which is not to say perfectly smooth):
decal_sheet.jpeg

I need to decide whether to put the big LauncherX logo on both sides, or just one. The real LauncherOne *does* have it on both sides, but because it doesn't have the wings on the side, the two logos are able to be 180 degrees from each other.
1620093994477.png

OK, that's only one side, but you can see everything is in line. I have confirmed there is a logo on the other side as well.

On the LauncherX, the wing pushes the logo upwards:
1620094177750.png

I already made it smaller to avoid having it go over the top (although looking at it now, I should probably move it back a bit). If i put a logo on both sides, it starts to look a little crowded from above:
1620094528495.png

Anyone have an opinion?

[looking at the LauncherOne right next to my model makes my proportions look really off... probably could have looked a bit more accurate with BT55/60 instead of BT60/70... that's the last time I'll show the two of them together, I think]
 

boatgeek

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The original rendering make it look like there might just be one LauncherX, on the upper port side. Maybe try it that way?
 

BABAR

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I like symmetry. Put the logo on both sides.
Symmetry is over-rated ;)

 

jqavins

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If I put a logo on both sides, it starts to look a little crowded from above:
View attachment 462742
Only a little, if at all. If you turn off the CG and CP indicators it will look less so.
Anyone have an opinion?
Go with both.
[looking at the LauncherOne right next to my model makes my proportions look really off... probably could have looked a bit more accurate with BT55/60 instead of BT60/70... that's the last time I'll show the two of them together, I think]
Obviously, Launcher X is a later version than Launcher One. It has bigger fuel tanks.
I like symmetry. Put the logo on both sides.
Yes.
Symmetry is over-rated ;)
Only a little.
 

Bruiser

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I like symmetry so my vote is for both sides but I really think you need this on the bottom
1620138090537.png


You can do it and it's be awesome!

-Bob
 

neil_w

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I like symmetry so my vote is for both sides but I really think you need this on the bottom
View attachment 462841

You can do it and it's be awesome!

-Bob
I agree it's cool but that would have been incredibly tough to execute. I decided (and committed) long ago to follow something more akin to the current "real" paint scheme.
 

Bruiser

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Real is over rated! Make it your own :)

logophoto.jpg



Oh, oh, oh! I had to edit because once you do it, it is real :)

Mr. Alway once replied to a photo I sent him that the rocket in the photo was not painted in an actual paint scheme but then continued that since it was painted that way it is now an actual paint scheme :)

-Bob
 
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