A "fish out of water" makes a splash

[martinjaymckee]

So, this past Saturday I made my L2 attempt with a scratch-built, 4" blue tube airframe. The rocket, the "Fish out of Water" has a 38mm motor-mount and was designed around a a fiberglass nose-cone I've had for several years ( I found it cheap ). Here's the required pre-flight shot.

What was supposed to be a fish, ended up as something of a whale -- at liftoff, it was over a pound above the weight I had intended ~8lbs. Still, well within the safety range of the selected engine -- a CTI J357. Results? A beautiful flight up to 2807' with a perfect recovery... 60' from the pad! Cool, a successful L2 certification flight.

Since I missed doing a build-log, I thought I'd do a bit of a post-mortem of the whole design/build/fly process. So, I'll begin with the end. As I said, the flight ended around 60' from where it started. No one in their right mind would expect such a short walk to recover an almost 3000' flight -- dual-deploy or not. When I started planning for an L2, I was working on a completely different design ( to be launched on a CTI J530 ) that would have gone to 7500'. As such, I wanted a tracker just to make sure I recovered the rocket. For controlling the dual deployment and doing the tracking, I chose an Eggtimer TRS. The construction was fun and testing went well. I designed and built a magnetic switch to go with it. I also built a tracking box that combined the Eggtimer LCD with a GPS module and a microcontroller -- it was programmed to direct me right to the landing location. What I learned though, on this flight, was that the week-and-a-half that I spent on building the tracking box was wasted if it's going to be used on flights that are are never going to go out of sight. Of course, now I have a nifty tracking box.

The Eggtimer TRS has proven to be quite nice to work with. Having downloaded the data from the flight, I've lashed up some initial graphs of the flight.


The graph shows a vertical line at some particular events: apogee, drogue and main. It shows exactly what I wanted to see. Smooth altitude data, drogue event right at apogee and main event around 600' ( which is where it was configured to be ). While the flight used dual-deployment, it was not a standard two-compartment arrangement. I used a Tender Descender to release the main chute. So, this was my first DD bird. Moreover, I designed the drogue/pilot chute, main chute and deployment bag. I was lucky enough to have my mother ( much better at sewing than I ) help me with constructing the whole recovery system. Neither of us had done much with rip-stop nylon ( just a couple of kites we built when I was a kid ). We also made a Nomex protector and a d-bag casing out of Nomex. In two flights ( I did a recovery system test last month ), the recovery system has worked flawlessly. What I do find interesting, however, is that during one of the tests I did ( towing the parachutes behind the truck ), the main chute was able to deploy just fine but would not inflate. So, have I just been lucky? I don't know. It always works fine opening in just a small wind, so I felt comfortable flying it.

What else needs a postmortem? Quite a bit, probably. At some point I need to analyze the paint job. Another thing I learned on this one is -- I need to plan at least twice as long to paint as I think it's going to take.

Martin Jay McKee

 

[rharshberger]

Uhhh paint job, Uhhhh Wow!

 

[dixontj93060]

Great report! Congrats on the L2! Quite the fashion statement with the launch attire also.

 

[Nick@JET]

Congrats on the L2! Very cool and 60' from the pad, that will be one to remember!

 

[KenECoyote]

Congrats and kudos! :clap:

I also like that you wore a tie for the cert! However I think a fishing outfit and a fishing pole would've been more appropriate. :wink:

 

[neil_w]

Uhhh paint job, Uhhhh Wow!

Yeah, what he said. Would love to see how you did that.

 

[kcobbva]

very nice paint! Well done and congratulations!

 

[Bat-mite]

Excellent. Great job!

 

[RocketRob]

Uhhh paint job, Uhhhh Wow!

Trust me, this pic does not do any justice for how beautiful this rocket really is!

Thanks Martin for coming down and flying with SCORE for your L2 flight, an amazing flight and one of the best looking rockets on the field for a long time!

We look forward to seeing more project from you in the future and will come down for one of y'alls launches this year.

Happy flying
-Will

 

[ActingLikeAKid]

So, this past Saturday I made my L2 attempt with a scratch-built, 4" blue tube airframe. The rocket, the "Fish out of Water" has a 38mm motor-mount and was designed around a a fiberglass nose-cone I've had for several years ( I found it cheap ). Here's the required pre-flight shot.

View attachment 293239

Launching with style, I dig it!
I briefly thought about how fun it would be to dress up for a launch. Then I checked the weather for next week's launch. It's going to be nudging triple digits. Think I'm going to go with something a little more light-weight and breathable.

 

[martinjaymckee]

Since the consensus seems to be that some review of the painting process would be nice, I'll get started with that. Will was awfully kind with his comments on my rocket being beautiful. I'm not sure that I would hold it in that high esteem, but I am ( appropriately ) proud of it. I've never been one to like finishing my rockets. I don't really like painting, and I hate sanding. But, to me the L2 cert was all about learning new things and getting better at my craft. So, that meant doing more than a protective paint job. To that end, I started with a small ( and much simpler rocket ). Anyone who hangs out in the MPR forum may have seen this one before, but I'll include it here. This is my Mad Duck ( much more apropos when the eyes are actually lit -- and bright red ).


Working on this I got to learn a bit more about painting process. It has a fairly simple paint job, really, with an undercoat of light-green primer, a base coat of white, and then segments of it repainted and masked slowly. This was really the first step in painting the Fish out of Water. It gave me the confidence to progress. So, a water bird lead to the fish... somewhat appropriate.

Here are some of the details that I'll describe as I describe the process. These show particular problems that had to be solved in assembling the paint job.

The first is a profile shot of the head ( nose? ), then we have the mid-point of the rocket which contains the lateral fins and the tail fins -- both top and bottom. The head details were produced almost entirely with taped masking lines, while the fin details were stencils. And here are a few more that show how it was tied together.

This first image shows the interaction of the fins with the scales. The second, a bit more detail of the eye, and the final one a better view of the bottom of the head and mouth. I think this image shows the taped lines at the head quite well.

All together there are six rattle-can colors on the fish: black, gold, yellow, coral, blue-green and silver. Add to that a primer coat, and you're looking at nearly a dozen cans of paint that went into this ( still, fairly small ) rocket.

Those of you who have attempted more complex paint jobs will no doubt already be thinking about the process you would have used. In my next post, I'll outline the process that I took to lay the paint down, maybe talk a bit about some design decisions and, hopefully, describe both the good and bad of working on this.

Cheers,
Martin Jay McKee

 

[martinjaymckee]

Okay, so, we know what this rocket looks like. The question becomes, how did I get from raw blue-tube, plywood and fiberglass to the final result. If you want a nice video version of "how I did it," you can go directly to the YouTube video that acted as my inspiration -- that's here, https://youtu.be/Ollp0IMvi7A . As for this particular rocket, I don't have any process shots ( I squeezed the entire paint job in less than two weeks -- big mistake! ) so I'll have to be doing lots of explaining, but we'll see what we can do. Anyway, first things first -- primer coat.

The rocket was built, as I've said, on a blue-tube core, and has 1/4" aircraft grade plywood fins. The boat-tail is made of internal foam-core board formers and a foamcore board outer surface. The boat-tail and fins were then covered ( tip-to-tip ) with a veil coat of 0.5oz. fiberglass, just to seal the surface. Spiral groves and other surface imperfections were then filled with vinyl speckling. At the end of the first filling pass, there were still plenty of surface imperfections. As I said, I don't like sanding ( or filling ). Besides, I was not going for a mirror finish. This paint job was going to be all about texture. A couple of imperfections here and there weren't going to be an issue.

After filling, the first coat of primer was applied. For primer I used Krylon Max Primer/Paint, Ivory Satin. It's a truly hideous color that I got at a massive discount ( $1.60 per can ). It's not the best primer I've ever used by a long shot, but it was good enough. A couple of cans later I had good first-coat coverage and let it dry for 12 hours ( remember, to little time was left to paint, I should have waited longer ). The next morning, I sanded down the first coat and filled low points with spackle again. Late in the day, I sanded and repainted with another coat of the Ivory Satin. Sand down once more, and the rocket's ready for the base coat.

The base coat on this bird ( erm... fish ) was interesting because it is half black and half gold with a fade between them. To begin with, I assembled to rocket and placed it on the stand vertical. I sprayed the goal onto the "bottom" -- using a mist coat and then a heavier coat. Once this was dry, I started on the other side of the rocket with the black, pushing it right about the the middle of the "sides" of the rocket. Again, I did one mist coat, but I then did two heavier coats. Once the black was dry to the touch -- a couple of hours -- I did one more coat of the gold to minimize the effect of the black overspray that had "muddied" the belly of the beast. Once the base coat was on the rocket, it was in a form that it would have been at least modestly launchable, and it looked orders of magnitude better than it had in the Ivory Satin. It was just a pretty ordinary looking black and gold paint job though, and most of it was destined to be covered.

The trick with this paint job was to use stencils to the max. Rather than spend hours ( or days... ) cutting them out, however, I designed them on the computer ( using an AutoCAD clone called Draftsight, much recommended ) and laser cut them out of watercolor paper. Water color paper was perfect for the stencils because it is rugged and about the right weight ( what I used for my stencils was around 90lbs., watercolor paper is available both lighter and heavier ). Laser cutting, of course, has the advantage of being fast, but it's also much more accurate than cutting out by hand is likely to be. So, referring back to the last post and the details, I started the "fish" designs by spraying on the lateral fins mid-way down the rocket. I used four stencils to create these fins ( the most I used for any effect, actually ).

The first stencil I used is the one at the top left of the first image. This was taped to the rocket and the area around it masked off. A two-color fade was then applied using yellow over the entire area, and coral from the base of the fin back to around half way. The second stencil ( bottom-left ) was then applied to block off the base of the fin and a quick spray of gold was added to produce a three-color fade in the fin and a solid coral base. While I was working on this, I started on the tail fins also. Luckily, they were far enough apart that I didn't have to worry about overspray, so I could make progress on two things at once. The tail fins were even simper. The stencil in the second image ( yes, I'm really glad I didn't have to cut that out by hand! ) was placed flat on one fin and the adjacent fin was masked off. Then the yellow/coral two-color fade was applied. That's it. The space between the fins was taped off to keep it clean, but the fins only took about fifteen minutes per side, between masking, painting and drying time. That's the value of using a loose mask that doesn't have to touch the surface. In all, the two lateral fins and eight ( two sides of four fins ) tail fins took about three hours to apply. Once the lateral fins had dried, the fin masks, pictured on the right, were applied, to protect the fins while the scales were being applied.

The scales were really where the whole design began and they could either make or break the design. Believe it or not, much of the design time that went into the stencils went into figuring out just how big the scales should be and how much space they should have between them. I'm amazed at the final result, actually, because it looks right to me. I got lucky, given that this was a first attempt. Anyhow, I used a total of five stencils to apply the scales.

The stencils I laser cut are the three in the center. The far left and far right I cut by hand when I had figured out just where I wanted the scales to sit on the rocket ( beginning just a bit below the leading-edge of the fins on the top of the rocket ). The stencils are basically in order from bottom to top. The small stencil with five cut-outs was used to reach in to place the first set of scales just a bit inset into the fins and to make sure that they started centered. The stencils were simply taped to the surface of the rocket and masked top and bottom. Because the stencils don't lay down perfectly against the surface, there is some overspray past the edges. It's really noticable on some of the lines, less so on others. In the case of a standard rocket paint job, this would be a deal breaker, but since this was a fish, it actually added some nice "organic" feel to it. I started the fins at the base and continued up, allowing time for the layer of yellow paint to dry before I reattached the next stencil. I continued all the way up to the nose, going right over the lateral fins ( that were masked with paper shields at this point ). Also, I simply laid down a coat of the yellow. Once I had completed the yellow scales, I went back with the far right stencil ( blue-green in the image ) and chose some individual scales to respray with gold. This created a two-color fade on specific scales, adding interest to the surface and making it feel just a little less "flat."

Next I moved on to the head. As I said, I had painted scales all the way up onto the head. This was just so that when I masked it for the gills, the gills would overlay scales everywhere. I decided on the line of the gills, masked it with tape and sprayed the bottom of the head in gloss black. I talked about how the stencils can lead to a soft line. This is precisely why I used taped lines on the head -- to avoid that softness. One of the things that you learn in drawing and painting classes ( in particular ) is to use a variety of line weights and styles. The body had soft lines, so the head needed crisp lines. Once the black was dry, I remasked with a line up just a bit further and sprayed the head in it's two-color fade of coral ( on the belly ) and blue-green ( on the top ). This is where I ran into the most trouble. I used way too much paint trying to get the blend line in the middle of the sides. There was wind out and I kept getting huge overspray that I had to fix, or the paint was being blown off track. I've said it again -- take whatever time you think you need to paint, and double it. You might have enough time then.

Once the head was painted, I removed the masking and proceeded to the final details: eyes, mouth, and blue-green scales in the body. The last in that list of details -- individual blue-green scales -- was easy. I just used the same "single-scale" stencil and sprayed them in, trying to figure out a good distribution. One thing that irks me is that I ended up ( somehow ) with two directly next to each other on the bottom.... oh well. Probably wouldn't bother anyone but me -- at least, if I hadn't just mentioned it. The eyes were tape masked and sprayed with yellow. That went okay, though the edges are a bit rough. Then they were tape masked, after what seemed like sufficient drying time, and sprayed with the black pupil. One of them worked okay, the other pulled paint out of the yellow of the eye. As it happens though, it wasn't the yellow paint that was the problem. It was the ultra-heavy coat I had put on the head as a whole. The yellow came off with a chunk of the coral. Darn. Well, I was out of time ( two days to launch ) so I sprayed some of the yellow into a yoghurt container and brushed a repair back onto the eye. I had wanted to finish the eyes that day, but no such luck. I did, however, mask off the mouth and spray that with the gloss black.

The next day ( T-20 hours to launch ) I masked and sprayed the silver highlight into the eyes. And that was it. Rocket done and painted. Basically all of the issues that I had during the painting came down to not taking enough time between coats of paint. In the end, it was an "easy" paint job -- needing only a handful of stencils and some fairly basic masking; but, it wasn't a simple paint job. It really took quite a bit of thought to come up with a set of steps that would make it easy to get the paint on there right.

Would I do it again? Yes. I think so. Is there anything I would change? I think you can guess. More time. But, while I think it works fine on this rocket, I would also like to get myself putting more time into the surface preparation. While I think the paint looks pretty awesome thus far, it could always be better.

Martin Jay McKee

 

[neil_w]

Impressively ambitious and beautifully executed. Bravo to you sir.

 

[The_Lone_Beagle]

You know, everything looked fantastic, but, there is something not quite right...oh yeah, that's it. The tie...next time, you should wear this:

https://yournecktieshop.com/rainbow-trout-fish-ralph-marlin-necktie-t29415

 

[ksaves2]

There's one problem with really nicely painted rockets. They have a tendency to get dinged up really good the longer one flies them. I'll wet sand and clearcoat with more wetsanding and rubbing compound followed by polishing compound sometimes and
it leads to the lacquer sometimes "flashing" sunlight even when the rocket can't be resolved by the eye at altitude. The intermittent flashing can give away the position. But oh my gosh, the time factor at getting a really nice finish can be a pain.
I've resorted to colored tubes now and leave it at that. Especially for rockets that are test mules for research motors or tracking setups. Kurt