Starship Avalon: build thread

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Cutting your own fins isn't so bad. Shucks! Every once in a blue moon, I wind up with something with die cut fins, and I feel like I'm cheating. Besides, you never know what grade or condition the wood will be when you order that way. I prefer to hand pick my balsa/wood, so I know what I'm getting. Crafting your own fins is like framing your own poster or art work. I know, I know, die cut is easier...........sigh......
 
My concern was the need for a lot of curved cuts that would need to be very precisely matched. I am now convinced (after another project) that I can do it justice.

Hand-picking balsa is great if I can find a local place that has good-quality stuff. The balsa rack at my local Michael's has degenerated into a complete disaster; I've been buying more of my wood from Ace lately (with my trusty scale in hand) with mostly good luck but a lot of the boards are pretty warped. I haven't combed through their 3/32" balsa stock yet, will do that sometime this week.

I got very lucky with my last laser cutting order in that he used good-quality balsa at almost precisely the density I was looking for.
 
I've ordered balsa quite often from www.balsausa.com and have been very impressed with the quality of wood. You can amortize the cost by ordering a good quantity if you like to scratch build and can think ahead for future projects. I like to build/fly R/C airplanes and I've acquired quite a good stash of wood to choose from whenever I need it. Initially expensive perhaps, but worth every penny down the road.
 
That's interesting Neil. I have the luxury of a Hobby Lobby and a Michael's both. HL usually has the wider 4 & 6" boards I'm looking for, but our Michael's actually has better quality wood. You should report it to management. I did that with HL when the stock they had was shoddy and they didn't even know it was bad. Sat there for months that way. They've since replaced all of the bad boards. Surely Michael's would do the same.
 
I realized I had some good 1/8" balsa leftover from the APRO Lander build, so I tried making one fin. The balsa cut very easily; papering however was quite challenging. The almost-finished result:
ImageUploadedByRocketry Forum1485307540.328263.jpg


That's a 3-piece fin, the center column and two points on left and right. I still have a bit of clean-up sanding, and filling of the divots in edges (I'll avoid those in the future). But it's a decent fin. I think the front fins (of which that is an example) will be surface mount, and I'll TTW the rears since they're more likely to bear the brunt of a hard landing.
 
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Here are the next two fins, before I attempt to destroy them with papering:
ImageUploadedByRocketry Forum1485468929.496827.jpg
Without the paper you can see the three-piece assembly. On these two I blended the curves of the pieces better, mainly because I rounded the leading and trailing edges *after* assembly. That made the sanding very delicate, but the end result is much better.

One obvious characteristic of cutting these fins by hand rather than laser-cutting: after all the clean-up sanding is done, these pieces are not exactly the same shape. For these guys it's fine, and no one will notice, but they are just not super-precise. For more traditional fins with straight edges, it would be much easier to sand them all to exactly the same size and shape, but for these it's really difficult.

After I paper these two I'll start on the rear fins.
 
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That's quite the exercise in grain direction.

Looking forward to seeing those go on.
 
Ummm... Just an idea/question. If the spiral fin's outer dimension was a match for a body tube diameter (say BT-70, or BT-80), couldn't you cut those fins out of the proper body tube and save yourself some of the hassle? Another idea for strengthening it would be to go with a tube coupler material, hardened with a wood hardener such as Minwax's product.
 
That's quite the exercise in grain direction.
Indeed, and it's probably not even necessary once the fin is papered and mounted. I was actually afraid that if I cut the fins out of one piece (with grain perpendicular to the root) then I'd be pretty likely to snap those things off while sandling and/or simply handling.
Looking forward to seeing those go on.

Yeah, me too. They look so small and delicate, I'm actually having trouble imagining them supporting those bit spiral pieces, but we'll see how it goes. And I've thought of another interesting challenge I'll have positioning the front fins, which I'll describe (along with, I hope, a good solution) when the time comes.
Ummm... Just an idea/question. If the spiral fin's outer dimension was a match for a body tube diameter (say BT-70, or BT-80), couldn't you cut those fins out of the proper body tube and save yourself some of the hassle? Another idea for strengthening it would be to go with a tube coupler material, hardened with a wood hardener such as Minwax's product.
As built, the diameter of the tube would need to be 5". And as it turned out, fabricating the spiral pieces was just about the most fun I've had in a long time (no comment), so I'm pretty glad I went that route. And I think it'll actually look a bit nicer for those pieces to have a bit of thickness and heft to them. In the movie, those pods seem to be where all the passenger compartments are, so they're quite thick.

Anyway, it could certainly be done by slicing a large diameter BT, but I'm glad I went the way I did.
 
Anyone who has read my build threads is probably sick to death of hearing about fin papering, but the process continues to fascinate me, and I keep getting better at it. Thought I'd illustrate just a few aspects of the process that I haven't covered in too much detail before. These are probably the most challenging fins I've done.

Recall that I'm using Avery label paper.

After the paper is on each side of the fin, I trim some of the excess, not too close to the balsa; just enough to get rid of excess material.
ImageUploadedByRocketry Forum1485570091.297198.jpg
Note that for these fins, I didn't extend the paper all the way to the points of the fins, because sanding/trimming out there would be extremely difficult to do without breaking the point off.

Next comes the most delicate operation, sanding off the excess. The non-rounded edges (i.e., the root and in this case the tip) are easiest, so I get those out of the way first. I sand along the edges, *gently*, using 220 grit sandpaper. I use a very small piece, roughly 1/2" x 1.5", wrapped around the fleshy tip of my index finger, so I can apply force very precisely (this is also how I'm rounding my fin edges these days, albeit with 400 grit). I go back and forth on the edge with the sandpaper until the dark grey undercoating of the paper shows through evenly across the edge:
ImageUploadedByRocketry Forum1485570102.308120.jpg

I do *not* sand all the way through the paper; if I do then it means I'm sanding the wood, which I do not want to do. Once the edge is sanded, the excess paper should pull away fairly cleanly (grab and pull away from the fin, parallel to the label sheet, to avoid lifting it). Here's that edge after the excess is pulled off on both sides:
ImageUploadedByRocketry Forum1485570113.674262.jpg

Next I apply approximately the same technique to the curved edges, which in this case are rounded. This is much harder because there isn't a sharp edge on the fin to cut through the paper as you sand. Nonetheless, the sandpaper will find the high spot on the wood and eventually we'll once again get that nice dark grey line (a bit wider and more diffuse this time):
ImageUploadedByRocketry Forum1485570122.878769.jpg

This sanding is done very gently and carefully, particularly near the point. Once again, the excess paper should now pull away cleanly from the fin with only a slight amount of force. For the first side (I haven't sanded the "underneath" side yet), I usually do this by squeezing the paper between my thumb and forefinger, working my way along the edge, until it looks like this:
ImageUploadedByRocketry Forum1485570131.602542.jpg

If at any point I run into a spot where it won't yield to very slight force, I sand a bit more and try again. This is the first build where I've really gotten this right, without sanding completely through the paper at any point.

Eventually all the edges are done, and I go over the paper edges with some finer sandpaper so smooth out the rough edges left by the 220. In this case, the result is probably my best papering job ever:
ImageUploadedByRocketry Forum1485570141.524304.jpg

Note that on this particular fin (not the same one shown in the previous images) I even got the paper almost all the way to the point without damaging anything.

I finish with a thin line of TB II around all the edges, and a final fine sanding to leave it all smooth. These will look good when painted, assuming I don't screw up the paint job.

And now I'll try not to talk about papering any more on this build.
 
Ready to attack the rear fins. Had to think about this quite a bit. Here's the plan:
rear_fins.png

As I mentioned previously, these fins will be TTW because they are likely to bear the brunt of landings, since the rocket will presumably land on the helical pieces. Now the helical pieces will probably just break off the fins, while the fins stay put. But I digress.

The slots will go all the way to the rear end of the BT55. The rear notch on piece #1 is designed to rest directly on the rear centering ring (in fact, the little ledge is .021 lower than on the right, because there will be no BT wall there.) In front, it would be easier to cut piece one straight down, but then I'd have no way to precisely position part #2. As it is I'll be crossing my fingers.

I made the tab a bit taller than necessary, so I can sand it until it fits correctly (will never again make the mistake of making the tab too short, I hope).

Pieces 1 and 2 will be assembled and papered and then (eventually) installed. Part 3 will be trimmed to shape (not yet sure what that shape is), papered, and then attached at the very end. That should be fun.

On to the cutting.
 
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Passengersavalon1.jpg
 
Cool! Thanks for posting that. I looked for something like that when I originally started this thread but couldn't find it. Did they have any good pics showing the external decor?

I think I got sort of the general idea (which really all boils down to the helical pieces). Seeing it more clearly now, I can imagine a few things that could be done differently, particularly the rear ring, but at this point I ain't gonna mess with it.
 
That was over at Element14, didn't see the externals because I was skimming for that image while trying to avoid spoilers ^_^

Edit: Wired has some stuff : https://www.wired.com/2016/12/seeds-inspired-swooping-starship-passengers/#slide-2

Also some good sketches here: https://www.wheretowatch.com/2016/12/passengers-production-designer-takes-trip-outer-space. I don't think they match the images from the movie exactly, but they do give some ideas, particularly around the rings. I could conceivably do something with the larger rear ring that looks like a bunch of, uh, pods or something rather than just a simple ring. Or maybe add that to the decor.

Also, as shown in this image (https://blog.pond5.com/wp-content/uploads/2016/12/passengers_avalon.jpg), there appears to be some sort of 6-pointed star logo at the top of each pylon.

And clearly, the windows (for some reason) all point to the side and interior of the helix, none point outward. I'll have to think if there's any reasonable way to incorporate any of this stuff.
 
The rear fins were a bit more difficult than the fronts, due to (a) those damned TTW tabs, and (b) a very uncooperative piece of balsa, which simultaneously had some almost uncuttably hard grains, and a a tendency to split at the ends of cuts. Here's one fin, before papering:
ImageUploadedByRocketry Forum1485900911.343958.jpg

And here's the finished set:
ImageUploadedByRocketry Forum1485900919.635480.jpg

I have to say, despite the fact that the resulting fins are not all exactly the same shape, and have a few imperfections, there is definitely some extra satisfaction in having cut them by hand. I still would use laser-cutting in situations where high fit precision is required, these will be good for this model, and they feel quite strong in their finished form.

I'm just about out of things to do before I collect the parts for the remainder of the project. I hope to have my BMS order submitted in the next couple of days. All I really need are a couple of body tubes and centering rings.
 
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Lest anyone thing I've forgotten or abandoned this build:
ImageUploadedByRocketry Forum1487995985.397462.jpg

Two main body tubes are cut to length, and the fin can tube is marked for the TRW slots. Once I get the spirals filled I can get down to cutting and assembling.
 
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Filled the spirals on the fin can and cut the TTW slots.
ImageUploadedByRocketry Forum1488161364.383721.jpg
Did a dry fit and I think everything fits together pretty well. I might need to sand the tabs down just a hair (so hard to tell when they're exactly the right depth), but I'll wait on that until it's time to glue.
ImageUploadedByRocketry Forum1488161355.736284.jpg
These slots came out better than my last attempt; they're almost exactly the right size (for Biohazard I made them considerably too wide and had to fill them later). Yay me.

I changed my plans slightly; I had intended to cut the slots all the way to the back of the BT, but instead I decided to go just to the centering ring and leave the rear ring of BT intact. Just means that I have a bit less to worry about with regards to the to back end of the BT holding its shape.

Somehow this rocket seems smaller than I expected. I'm almost having doubts about the 24mm motor mount, but then again it should be pretty draggy, what with a the 1/8" fins, two rings, and the helixes. I suppose I can always use an adapter if I find it works well enough on C6's.
 
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Did some assembly today. Some of it went well.

First, I built the motor mount, which is really just the end of the long BT50 that runs through the whole rocket. This is what it looks like:
ImageUploadedByRocketry Forum1488684196.430691.jpg

The ring is positioned at the back of the fin can (more on that later). I realized, nearly at the last minute, that I couldn't wrap the hook with tape because that tape would be under the rear fins, and therefore would interfere with the TTW attachment. So I did something I've done before, which is just blanket the top half of the hook, and the bit just on the other side of the centering ring, with 30 minute epoxy. It's not going anywhere, the TTW locations are clean, and hook has enough room to bend and allow for motor insertion. So far so good.

The front centering ring was positioned about a 1/2" behind the front of the fin can.

Next I glued on the fin can:
ImageUploadedByRocketry Forum1488684215.197067.jpg

Here's a close-up of the back end:
ImageUploadedByRocketry Forum1488684227.221950.jpg

I let the centering ring (1/8" light ply) extend just a bit behind the BT, to give a "shoulder" for the transition to anchor to. I don't know if that's enough of a shoulder, but that's about all I could do.

The front looks like this:
ImageUploadedByRocketry Forum1488684235.611727.jpg
Here, I took a short (~1/2") piece of BT55 and sliced out a small piece so it could be squeezed into the end of the fin can. This provides a quite nice shoulder for the front transition. This is why I put the front ring 1/2" behind the front of the tube.

Now for these guys:
ImageUploadedByRocketry Forum1488684207.289263.jpg
I made these using a modified version of Chris Michielsson's "super shroud" technique (I will document this technique at some point); they are made from 2 layers of 65 lb cardstock and came out quite good on my first try. The longer front transition was easier, so I went to install that one first. I applied glue to the tube and the shoulder and got ready to slide it on:
ImageUploadedByRocketry Forum1488684245.749856.jpg

Approximately one minute later, I was looking at this:
ImageUploadedByRocketry Forum1488684253.212475.jpg
That is not a result of frustration (although I was frustrated), but of the fact that the front glue bead grabbed too quickly and left me unable to get the whole transition into position. So, with the glue setting, I had no choice but to rip the whole thing off. I'll make another and try again; next time I will not put a glue bead on the body tube, only on the shoulder. The front of the transition will be secured only with a fillet after the fact. I should have learned this lesson on my last build, but I forgot.

So, let's look at the rear transition. This one has to provide room for the motor hook, so I cut a nice little slot in it like so:
ImageUploadedByRocketry Forum1488684260.457679.jpg
I put some CA around the edges of it and sanded it to make nice clean and reinforced edges. It provides just enough room for the hook to go through and be able to bend outward to insert or remove the motor. Actually, it could probably stand to be a little bit deeper; when the hook is fully extended it is pulling *slightly* on the transition.

But after further thought I'm not sure I'm actually going to use that transition. The large end of it is a tiny bit too big, and fits a little sloppily. I applied some CA to the edge and will try to sand it down, but if I'm not happy with the fit I'm just going to make another one of those as well.

Lucky it is quick and easy and cheap to make more transitions. :p

I kind of wish I had made this rocket one click larger (BT55/BT60); would have been easier to work with the slightly larger pieces.
 
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Approximately one minute later, I was looking at this:
View attachment 313685
That is not a result of frustration (although I was frustrated), but of the fact that the front glue bead grabbed too quickly and left me unable to get the whole transition into position. So, with the glue setting, I had no choice but to rip the whole thing off. I'll make another and try again; next time I will not put a glue bead on the body tube, only on the shoulder. The front of the transition will be secured only with a fillet after the fact. I should have learned this lesson on my last build, but I forgot.

I had a very similar situation this evening. Even though I didn't post it yet, I also didn't take any pics. I had major issues on the bench.
 
Two new transitions:
ImageUploadedByRocketry Forum1488918959.763692.jpg ImageUploadedByRocketry Forum1488918968.930355.jpg
Pictures show dry fits on scrap tube. They came out Very Good, let's see if I can mount them without ruining them.

For these I decided to skip the double layering and just paint their insides with CA to harden them up. On their own the difference is hard to discern, but in place (as in the picture) they feel quite solid. So I think they're good to go.
 
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Two new transitions:
View attachment 314022 View attachment 314023
Pictures show dry fits on scrap tube. They came out Very Good, let's see if I can mount them without ruining them.

For these I decided to skip the double layering and just paint their insides with CA to harden them up. On their own the difference is hard to discern, but in place (as in the picture) they feel quite solid. So I think they're good to go.
That's how I do mine. I can't imagine the need to double layer shrouds on a LPR rocket.
 
That's how I do mine. I can't imagine the need to double layer shrouds on a LPR rocket.

I think for ginormous ones (like on the you-know-what) I feel good with them double-layered, but clearly these small ones are fine as is. And it's a heck of a lot easier to make single layered than double, even though the doubling is not that bad.
 
A smooth layer of white glue usually works well. I have been printing up the transition templates on regular copy printer paper, then I glue stick that to the cardstock to make the transition. Sort of an alternative to double ply cardstock. I try to make the glue tab wide enough so I can cut the slot there for the engine hook for a boat tail.
 
A smooth layer of white glue usually works well. I have been printing up the transition templates on regular copy printer paper, then I glue stick that to the cardstock to make the transition. Sort of an alternative to double ply cardstock. I try to make the glue tab wide enough so I can cut the slot there for the engine hook for a boat tail.
Hmm, maybe I'll give that a try (the copy paper + cardstock laminate). I've been cautious about using too much white or yellow glue on paper stuff because it ends up puckered... not a problem?
 
I think for ginormous ones (like on the you-know-what) ........
Oh, I can see that too. I wish I had known about CAing and such back when I built my upscale Cobra. That tranny is pathetically weak compared to smaller ones. Those look pretty good Neil. Glad you're moving on with it.
 
Oh, I can see that too. I wish I had known about CAing and such back when I built my upscale Cobra. That tranny is pathetically weak compared to smaller ones. Those look pretty good Neil. Glad you're moving on with it.
Yes, I am eager to get on to mounting the fins on this crazy thing.
 
Hmm, maybe I'll give that a try (the copy paper + cardstock laminate). I've been cautious about using too much white or yellow glue on paper stuff because it ends up puckered... not a problem?
Yes it can soften and warp the paper, I should have said smooth and thin layer of glue. Paper thin :)

Once it dries you can add another layer for a little more strength, it doesn't take much. If have made some cardstock nosecones that are about as tough as plastic cones, small LPR size.
 
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