Starship Avalon: build thread

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Not at all. Mine were 4 - 9/16" long. Yours about 6"? Not much bigger than what I used, but then there's the pylons. If yours are longer, your can will be bigger.
 
Hey man. You like fancy fins. I wonder if you could morph this idea into something stable. I didn't like where my drawings went after I built this, and it flies really bad. Mostly flip floppy.

DSCF3145.jpg
 
It is. I just liked the way it looked. Fins too far forward are a bad idea anyway. I was hoping a boatload of nose weight would work that out and it didn't.
 
Copy that. Sorry Neil!

I've been listening to this thread for while, I think you're doing an amazing job bringing the concept to life and really look forward to seeing it!
Those wet-formed fins are super innovative.
 
Copy that. Sorry Neil!

No problem. I've hijacked a few threads in my day, and way worse than that. :)

Oh, and if you build that crazy thing Gary just posted (Gary, does that one have a name?), you *must* do a build thread for it.... or at the very least videos of its first flight. ;)

Actually, I'm looking at it again, and it seems that it could possibly fly fine if you just stretched out the BT a bit in front, so the fins are not covering the whole body. I bet it'd look fine that way as well. Maybe I'll noodle in OR with it.... I'm hoping for my next design to be something a bit simpler than the crazy stuff I'm doing here. Simpler but still interesting, and that one qualifies.
 
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I'm close to admitting defeat on the open-air motor mount. Too many ways to fail, too few to succeed. So I'm thinking of just replacing the open part with a transition, something like this:
avalon_alternat_rear.png
The transition itself becomes largely invisible (maybe I don't even need it, just an extended motor mount). I also added some nozzle doodads. What do you all think?
 
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If you're using a motor block ring, you could use a spent motor or empty case to center the rear most ring while you fix the fins/struts into place. It'll still have a motor sticking through it for flight, but in display mode it'd look sweet. Maybe thin ply or something stronger than Balsa to survive motor retention forces.
 
If you're using a motor block ring, you could use a spent motor or empty case to center the rear most ring while you fix the fins/struts into place. It'll still have a motor sticking through it for flight, but in display mode it'd look sweet. Maybe thin ply or something stronger than Balsa to survive motor retention forces.

The problem I can't seem to solve is motor retention. With the open mount, there's nowhere to put a hook (at least not that I can figure out). Friction fit will put a lot of strain on the mount structure during insertion and removal. Putting in a fixed rear retainer and having the whole outboard mount be removable is possible but seems needlessly complex and troublesome.

In general, I don't to be afraid of breaking the whole mount every time I load or unload. I agree in display mode it would rock. :)
 
Hard for me to see details in your images, but if there is no room for an engine hook, you're going to have to beef up the aft end so you CAN friction fit w/o damaging the mount.

For your other question, that artsy fartsy rocket was a destined shelf queen that I tried to fly. I know the fin laws of rocketry very well, so I wasn't surprised that it flew terrible. It's called Time Warp and I did some noodling of my own just yesterday. Stole your aft nose cone strake idea for it too. There's a video I have to hunt down but for now, here's a 2D rendering of said noodling.

Time Warp II.jpg

Here's a video. Photobucket, so I don't know if it'll let you in.
https://s343.photobucket.com/user/glbyrum/media/Launch7-27-10TimeWarp_zps4bd9d301.mp4.html?o=12
 
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For your other question, that artsy fartsy rocket was a destined shelf queen that I tried to fly. I know the fin laws of rocketry very well, so I wasn't surprised that it flew terrible. It's called Time Warp and I did some noodling of my own just yesterday. Stole your aft nose cone strake idea for it too. There's a video I have to hunt down but for now, here's a 2D rendering of said noodling.

View attachment 304983

Like! The nose strakes look really good with a conical nose cone.

Here's a video.

Well that was a good bit of fun. :)
 
Hi Neil,

My first post on this forum although I have been lurking here for years. I've been following the evolution of your design and would like to offer a solution to the motor retention problem. The folks at Rocketarium have plastic screw-on retention rings that would allow you to keep the open motor bay. The item can be found here: https://www.apogeerockets.com/Build...w-on_Retainers_18mm/18mm_Rocketarium_Retainer
 
My first post on this forum although I have been lurking here for years.

Welcome! Lurking is fun but posting is better. :)

I've been following the evolution of your design and would like to offer a solution to the motor retention problem. The folks at Rocketarium have plastic screw-on retention rings that would allow you to keep the open motor bay. The item can be found here: https://www.apogeerockets.com/Build...w-on_Retainers_18mm/18mm_Rocketarium_Retainer

I'm a big fan of the screw on retainers in theory (Estes has them too, in 24mm and 29mm), but you do need something to attach them to. The original design I posted doesn't have it. I could extend the rearmost tube to provide an attachment point, but then I think it would kind of ruin the spindliness of the whole thing.

And that's really the problem: a motor mount is not a good place for spindliness. Thus far I've thought of only one solution that preserves it while having sufficient strength, and it is likely to be too troublesome to build.

I'll keep thinking about it a while longer; I have plenty of time before needing to commit to a final design.

Thanks for the suggestion.
 
Made the nose strakes out of 1/16" basswood.
ImageUploadedByRocketry Forum1480457249.512126.jpg

Each is about 2.5" long x 5mm wide.

To actually get this build going, I need to gather the parts. To get the parts, I need to prepare the file for laser cutting the rest of the fins. I'll likely want to combine the job with at least one more, which means I need to choose my next scratch build or two and get them ready. Likely candidates are one of the unbuilt ones shown here or here, but it could also be something yet undreamed. If anyone has an opinion of which I should build, I'm open to suggestions.

So it'll be a little while before I get my act together on this one. Sometime this winter.
 
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I'm close to admitting defeat on the open-air motor mount. Too many ways to fail, too few to succeed. So I'm thinking of just replacing the open part with a transition, something like this:
attachment.php


The transition itself becomes largely invisible (maybe I don't even need it, just an extended motor mount). I also added some nozzle doodads. What do you all think?

While I hadn't noticed the open air engine mount, now that I'm aware of it, I'd say it's too likely to be damaged by a hard landing. For my Trident clone, I didn't have, nor really like the rings used for the engine detail, so I used strips of basswood to create something like the cone or "turkey feathers" like you see on the afterburners of jet engines. Mine were straight, and had a slope at the aft end.

Oh... Cool, I found some photos of it.

8682944498_016494e63b_n.jpg
 
That looks quite nice. Is there a retainer there, or did you just friction fit?

I've officially abandoned the open engine mount, but still haven't settled on my alternative yet. Retention continues to be the challenge. I can use a hook, but it'll be a bit more visible then I'd like (although not so bad if I do actually put the transition back there, so the hook could mostly live under it.)
 
That looks quite nice. Is there a retainer there, or did you just friction fit?

I've officially abandoned the open engine mount, but still haven't settled on my alternative yet. Retention continues to be the challenge. I can use a hook, but it'll be a bit more visible then I'd like (although not so bad if I do actually put the transition back there, so the hook could mostly live under it.)

Friction fit. However, a cleaver bloke could sand a notch under the "feathers" and use an engine hook retaining ring to hold an engine hook in place.
 
It occurred to me that I have all the parts I need to build the nose section, so I took the opportunity to do a little building. It's a simple assembly but I did have to ponder a bit how to get it together correctly.

I determined that I like the look best where there is exactly 1" of BT55 under the nose cone, before the BT50 and the strakes. I decided that the best approach would be to put the separation point just below the strakes, so the whole top portion is one piece. The reason this was anything but ultra-simple was that 1" of BT is not enough to fit both a nose cone shoulder and enough of an insertion properly anchor the trailing BT50. So I started with this:
attachment.php

On the left is a 5 1/4" piece of BT50, with an engine block in the end, just to prevent it from collapsing. In the middle, my 1" BT55 with a centering ring installed into one end (that'll be the aft end), and the nose cone with the end opened up.

Here's a view from the end of the BT55, with the nose cone dry fit, showing how little space there would behind the shoulder for the usual 2 centering rings to anchor the BT55:
attachment.php


Next I applied 3 spreads of glue:
attachment.php


The Titebond is right around where it will meet the centering ring. There is epoxy spread around the inner edge of the BT55.

The BT50 is inserted into the nose cone, up until the end hits, and the epoxy should contact. Here's where the engine block was needed; without it I could keep pushing on the BT and it would just collapse. This way it hit a hard stop. Here it is inserted; I use 30-minute epoxy so plenty of time to work here.
attachment.php


This way the BT50 is anchored into the nose cone itself, rather than a centering ring. After that the BT55 assembly is slid on, and I put a little fillet to seal the centering ring to the BT50 (it was a bit loose):
attachment.php

After some Bondo it is finished:
attachment.php


That was fun. :)

At my next opportunity I'll glue on the strakes.
 

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And here it is all finished.
ImageUploadedByRocketry Forum1481756316.528945.jpg
Hey guess what! I forgot to fill the spirals on the BT50. Probably not gonna worry about it at this point; I don't think it'll be terribly noticeable between the strakes. Still... :bang:
 
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I needed to figure out if my proposed paint scheme is, you know, doable. So I painted up a test piece of papered balsa using my exact proposed sequence:
1) Black base coat (spray)
2) Mask edges of all fins
3) hand-paint white over edges
4) hand-paint fluorescent yellow-green over edges

First I needed my paint. I mixed Testors fluorescent yellow and green at about a 3.5-1 ratio to get the color I wanted. Here's a family portrait:
ImageUploadedByRocketry Forum1483737435.404975.jpg

The green paint was much more powerful than the yellow, and I had to buy a second bottle of yellow to lighten it up after I added a bit too much green to the mix. I'd still like it a bit yellower, but it's OK as is. This is the color I really wanted for the Diamond Cutter.

Next, I painted my test piece gloss black, by hand. It looked like garbage, but since I wasn't trying to evaluate the black paint, I didn't worry too much about it.
ImageUploadedByRocketry Forum1483737417.651877.jpg
Next, I masked the edges using Tamiya 5mm masking tape for curves. This stuff doesn't necessarily produce the sharpest edges, but it is incredibly easy to work through the curves and get it exactly where I wanted. Here's the piece, masked up:
ImageUploadedByRocketry Forum1483737424.670550.jpg
Next I painted the white. Getting an even coat of white on top of the black was not happening, but I didn't know how perfect it needed to be (that's part of what I'm hoping to learn here). I ended up putting two coats of white on one of the edges, and one coat on the other, to see it it made a difference.
ImageUploadedByRocketry Forum1483737444.492963.jpg
Finally, I painted two coats of my fluorescent mix; here's the final result after unmasking:
ImageUploadedByRocketry Forum1483737461.643027.jpg
Here's the best I could do to get a close-up of one of the edges:
attachment.php

Thoughts:
1) It's definitely doable. Not easy, won't come out perfect, but doable.

2) The edge with two coats of white looks a *little* better than the one with a single coat; I'll probably go with two eventually. It would no doubt be better to spray the white, but that would mean a lot more masking and general hassle so I'll stick with the brush strategy.

3) The fluorescent paint looks great, but it is definitely hard to work with (no surprise). It is very watery, and doesn't cover well, making it hard to get anything like an even coat. I think my results here are "decent".

4) I need to wait until the paint is pretty dry before removing the masking tape. I got a little over-eager and messed it up a bit while removing (you can see my mess-up on the right end of the close-up above).

5) Although the tape is great, it's comparatively thick vinyl-ness doesn't conform to the surface quite like the paper masking tape does, and I need to be very careful that it's really pressed down everywhere before painting.

6) If, as in my previous renderings, I paint the tail rings solid green, I'll definitely need to spray the white undercoat to get a good even base. Even then I'm not confident the fluorescent paint on top won't be an uneven mess. I might explore other schemes there that won't require such a large area of the green.

7) To do the lettering, I'll use a paint mask from Stickershock23 and then do the same hand-painting routine on top of it. And then pray.

8) I'm not really 100% confident of doing the rocket this way, but I'll probably give it a go unless I think of something better.
 

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That fluorescent green and black turned out really nice! I may have to try that sometime.
 
A suggestion:

After applying the masking tape, spray your black again. Before you hand paint the white and green. Spraying the black will help to prevent any white or green from getting under the tape edge.

Another thought: After spraying the black, also spray a dull clear or flat clear coat. That will provide a bit of a rougher surface for the brush paint to adhere to more evenly.

It's a lot of work, but that's how the best paint jobs are done... Lot's of work. :wink:
 
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A suggestion:
After applying the masking tape, spray your black again. Before you hand paint the white and green. Spraying the black will help to prevent any white or green from getting under the tape edge.
In the past, Micromeister has emphatically suggested that spraying a layer of clear coat accomplishes the same thing but without creating as large a paint dam (because the clear lacks pigment and simply doesn't build up as thick). I buy that, and when/if I ever apply this technique I will do it in clear.

For this particular build, I was hoping to avoid spraying after masking (because then I'll need to do a lot more masking), although just maybe if I spray the clear coat then I won't need to fully mask, but just let the clear coat hit wherever. Then a very light amount of ultra-fine sanding will take care of the very fine dams that remain.

Given that my test piece above does show a bit of unsightly white leakage under the green, I definitely need to do something.

This calls for... another test piece! :) I don't know why but I seem to enjoy doing this experimentation.

Another thought: After spraying the black, also spray a dull clear or flat clear coat. That will provide a bit of a rougher surface for the brush paint to adhere to more evenly.

I think I'm actually going to try the whole thing in flat black anyway. The fluorescent paints prefer to be flat, and these black starshippy things look good in flat. My next test piece will be flat.

I need to find a good UV-resistant matte clear, any suggestions? Gotta go searching on the forums...

Scotty Dog said:
I likey the black/green.

I'm still debating whether to dump another bottle of yellow in there to lighten it up some more. What do you think?
 
After my recent wood-cutting extravaganza, I've decided that I'm just gonna hand-cut the fins for this model, assuming I can find a decent sheet of 3/32" balsa locally. Then I shall commence with that. Cutting and papering them all should take a little while; hopefully by then I'll have the rest of the parts in-hand, and then this build thread can stop sucking so bad.
 
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