BT-55 Snarky-ish Build

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TopRamen

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I've been out of the building game for too long, and I finally got fed up with talking about building rockets but not actually building them.
I don't have much room to work, so I figured I can at least pull off a small build.
A BT-55 Snarky inspired scratch build with a 24mm MMT will fit the bill nicely.
I was inspired by Marwady's "Snarky Plans" thread, and after staring at every single picture of many snarky variants, it was time to start making the components.

I drew my "Scoop Template" by hand, then by folding the proper width of paper once and cutting through both sides at once, I yielded a symmetrical form, which I taped to my tube. I then drew the lines on the tube and removed the template. I cut the shape out with my X-acto knife, then soaked the inner wall of the scoop tube with Super Thin CA, so it will withstand a gentle sanding to get it tuned up nice.
I've read all the build threads, and will be sure to mount my micro-buttons BEFORE I glue the scoop on.:wink:
I need to go grab some more building supplies from storage at my Mom's house, so this is all I'll get done tonight.
I might print some fin templates, or at least go make them in Openrocket.


Sure feels nice to be building something again!!!!:):):):):)


Snarky 002.jpgSnarky 003.jpgSnarky 004.jpg
 
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Here's where I made it to with my Ork. File last night.

View attachment BT-55 24mm Snarly.ork


Now I need to figure out how to make the other wing, since OR does not let you mount fins asymmetrically from each other, I need to make a second identical wing, then adjust it's radial position opposite the first.
Wish I could just clone the fin, but I guess I have to draw it to the same numbers as the first, then position it???

Perhaps I'll go review K'Tesh's threads.:)
 
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Here's where I made it to with my Ork. File last night.

View attachment 283315


Now I need to figure out how to make the other wing, since OR does not let you mount fins asymmetrically from each other, I need to make a second identical wing, then adjust it's radial position opposite the first.
Wish I could just clone the fin, but I guess I have to draw it to the same numbers as the first, then position it???

Perhaps I'll go review K'Tesh's threads.:)

Change the fin to free form. Set the number of fins to two. Then split fins, and then adjust the locations so that they are opposite of each other.
 

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I'm impressed with the cutting of the scoop, I couldn't dare attempt it.
 
I'm impressed with the cutting of the scoop, I couldn't dare attempt it.

Thanks. It was not bad as I thought it would be.

Even though I was out of practice, I have always had a great deal of manual dexterity and patience.
It took about 6-7 gentle passes of the blade to cut through.
It is far from perfect, but that is why I hardened it with the CA. Once I get some new sand paper I can fine tune it.

I've decided that this build is small enough that I'll fly it from my 48"X1/8" Rod, even though I am not a fan of rods.
This will simplify building, and I have plenty of launch lug materials.

Thanks to K'Tesh, I was able to do what he said and finish off the basic file. I have not made any account for the scoop, but according to an article that Tim Van Milligan wrote for the Apogee Newsletter, the scoop is rather superficial, and not as influential on performance as one might think, and if anything enhances stability.
I put 18g. of nose weight in the cone, though that was just to be on the safe side so I could run some sims. Might not even need that much, as 1.5 calibers of stability should be enough.

View attachment BT-55 24mm Snarly Revision 1.ork




I don't know if it is possible to model the scoop as a tube fin or not?
 
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Nice! Swap the angles of the wings & the rear stabs and you can build a sport-scale F-16 too! :)

Thanks.
Yeah, I've encountered those in my research into the snarky.


I got my fin templates printed and cut out. Went and picked up my Balsa stock at my Mom's earlier today, so I might even get around to cutting out my fins today.

Sanding things will have to wait, as it is raining outside.

I'm most likely do a layer of .5 or .75 fiberglass cloth on everything, as that barely adds any noticeable weight, but strengthens things quite a bit, and means I don't need as many layers of primer to cover any imperfections. I can get glassed components to exact dimensions do to the rigidity, so as to need less fillers or heavy fillets. Also cuts down on the amount of primer needed, and we all know how much weight primer adds. Primer makes me sad.:(

I do love glassing low-power stuff immensely.:)
It would also make assembly of all the components so much easier and better fitting.
Heck, glassing just makes everything so much easier.

She'll be a streamer recovery bird, like all my other LPR rockets, so it will be nice to not have to worry about hard landings.
 
I brought a bunch of parts home today from storage, so I have everything I need now.
Before I stopped building I had managed to aquire quite the selection of lite ply centering rings from BMS. :)
Even some small G10 bulkheads that will fit up in the nose cone nicely.
There was an unused Estes 24mm retainer, but it is bulky and I may just hold off and wait til' I can get another rocketarium retainer. They fit much better on BT-55 tubes, like on my Centuri and Eggspress.
I also may just use a hook. I have not decided yet.

Those 24mm Rocketarium retainers are SWEET!!! Perfect for BT-55!
I have an Aero Pack 24mm retainer on my Blue Bird Zero, and it is beautiful, but it's the most expensive.
Rocketariums can be found on Amazon reasonably.

Eggpress Painted 2015-05-07 006.jpgRocketarium Retainer Centuri 2015-05-06 002.jpg
 
In thinking about motor mount tubes, I remembered that my Centuri developed a crusty ring of black powder residue forward of the motors I had used, C11 and D12s.
I decided that this rocket will have a short MMT, just long enough to do what it has to do, that way I won't get a build up that will make it tough to fit longer motors like the F32 in there.
I also recessed the aft CR to accommodate a retainer.
I've made up my mind to get another Rocketarium 24mm.

View attachment BT-55 24mm Snarly Revision 3.ork
 
Top, your fins are all listed as OR's default thickness (.118"). I doubt that you're really using .118" thick fins. So, please, do tell.
 
Top, your fins are all listed as OR's default thickness (.118"). I doubt that you're really using .118" thick fins. So, please, do tell.

Yeah, I did not adjust that. I guess I should eh'???
I hope I remembered to change them to balsa instead of the default cardboard.:y:

I don't have a Micrometer, so I have no idea how thick the balsa stock I'll be using is.
I'll be using some nice sheets that were given to me. they will be getting the .75oz. cloth, so they will still be only a fraction of the weight of basswood, but much more rigid, and only slightly heavier than balsa.
I did before and after weights on one of my other builds to shut up the folks that wanted to say that glassing would add much weight. I also glassed an identical set of basswood fins in the same thread, and now have a spare set of fins.
I happen to have the left over balsa stock sheet from a stock Estes Crossfire, and my sheets are of identical thickness to that sheet, so, whatever the stock Estes Crossfire ISX uses thick.:)

Snarly parts 004.jpg
 
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I just got done making the launch lug from one of the little cardboard tubes that the Aerotech Copperheads come in.
I soaked it with super thin CA inside and out, and now it is hard as a rock.
Gently sanded the BT with 120 grit to cut through the glassine layer, then marked it with pencil and made a crosshatch pattern where my lug would go with my X-acto.
When the lug was fully dry and safe to handle, I roughed it up too on the side that would go on the BT.
Then I taped it into position to hold it straight, and tacked it on with more CA. After that dried I used PC Superpoxy to seal it up and make my fillets.
Then I used a really crumby camera to get pics'. I'm using my kitchen as my work bench. It was raining outside today so I could not go out to cut the wood for my new collapsible workbench.
I also put my centering rings on my motor tube and have that put together, but got sick of using said crappy camera. Pics' tomorrow on that.

Launch Lug Snarly 002.jpgLaunch Lug Snarly 003.jpg
 
I also sanded the scoop real nice so it is is perfectly flat on top by setting it on a sheet of sand paper and working it to and fro.
Then I sanded the inside edges that will mate to the body tube. I'll likely have to use the same tape and CA tack method to mount that perfectly straight before epoxying and then glassing over with .5 oz. cloth.
Hardening it with CA really paid off and made it easy to get it to it's final shape without damaging the narrowest tapered portion of it.
 
Top, your fins are all listed as OR's default thickness (.118"). I doubt that you're really using .118" thick fins. So, please, do tell.

I have revised my numbers to match what you had on your Crossfire ISX file for now, which is .098".
This had a positive effect in altitudes, and I'll likely take the time to round the edges of the fins, but more on that later, as I'm trying to figure a good way to do that before glassing.
I'm considering making a press, using neoprene, similar to what I use when I make a Kydex knife sheath.
Then I could shape the fins before glass, and still ensure that the glass contacts the entire surface area of the fin or wing as it cures. Vacuum forming is out of the question given my limited resources, but a couple slabs of granite, some butchers paper, peel ply and neoprene I already have, so theoretically this is feasible.
I need to do some tests on this method, so it may just have to wait til' a future build.
 
Now to find a decent 1:48 Scale Decal Set for a Warhawk or other similarly styled model airplane.

I started looking last night, and it brought back bad memories of how hard it was to find the right graphics for my TLP TAN-SAM TYPE 81. I ended up painting the decal for the eyes and teeth on that one by hand.:(:yawn:
I think I spent more time getting that part right than I spent assembling the rocket.


type-81 SAM 1.jpgTLP Livery 003.jpg
 
Here's my parts layout of where I'm at.

I grabbed enough Balsa stock that I can afford to make a few mistakes, as the whole 2 and 3 piece fin/wing thing is new territory for me.

Snarly parts 001.jpgmmt snarly 002.jpgSnarly parts 003.jpg
 
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Sweet!

I've magaged to piss off Micromiester once again, as evidenced by the "1 Star Rating".

I'll be sure to return the favor next time he does a build thread for one of his poke your eye out plastic model conversions.:wink:


Getting 1 Star on one of my build threads is a badge of honor for me, as it means I'm staying true to my building style.:cheers::headbang::w:
 
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Using a picture of the wing mounting templates from an actual Snarky, I resized and printed a template, which I cut out, then mounted to a black background and copied and printed again and again, til' I ended up with this sheet of templates. I then scanned this so I'll have the BT-55 scale templates on hand if I need more.
I will of course glue them to foamboard and cut them out. I'll fine tune them to my body tube/scoop, and have a few extras, so that I can use the ones that fit perfectly when I do my dry fitting.
I'm out of practice making foamboard jigs, so I have a feeling I'll be needing a few.:wink:


Snarly Fin Templates BT-55 Scale 002.jpg
 
Good to see you building again, I like your style!

It may be too late but I have my hands on my Snarky plans if they are still needed. I also have the Monogram F-86D with markings for 97TH FIS and 498TH FIS. Somewhere in my disaster of a shop are aftermarket sheets but they are lost to the chaos right now as is a Kittyhawk kit but I believe that the only markings with that one were British from North Africa. I'll dig when I can but knee surgery on Wed has me kind of hobbling around a bit right now.
 
Thanks Bill.

Help is always appreciated, but I'm doing fine on this one so far, and pretty much have everything planned out now.
You take care of your Knee first and foremost. Best of luck with your surgery.

Marwady is also building a Snarky, but in BT-80. I referred him to your build thread.

A actually used the picture of your parts layout in that thread to make my wing templates.:wink:
 
looking good so far. I actually have this kit and the Lexxjet just haven't gotten around to building them yet. I have two builds on the bench that I've been dragging out so I should get those done. Just been working a lot and other non rocketry projects have had my time consumed.
 
looking good so far. I actually have this kit and the Lexxjet just haven't gotten around to building them yet. I have two builds on the bench that I've been dragging out so I should get those done. Just been working a lot and other non rocketry projects have had my time consumed.

Thanks.
I'm really enjoying this project.
 
Top - Are you going to paint the inside of the scoop red? I always wonder how that was done? Do you paint the entire area red first and then glue on the scoop or just brush the paint one?
 
Top - Are you going to paint the inside of the scoop red? I always wonder how that was done? Do you paint the entire area red first and then glue on the scoop or just brush the paint one?

I actually have not decided on the paint scheme yet.
I've thought about how to paint the scoop, and it seems that the best way to paint the inner walls of the scoop is to paint it first, so that when it comes time to play the "Masking Game", you only need to mask off the openings of the scoop, and not the entire rocket.
 
Yeah, I need to get that thing done!

The Saber Dog decals and Snarky info are both easy access. After doing some searching for F-86D images, I may have to re-think the paint on my Snarky, it would look awesome in 50's-60's USAF livery. Here is a link to the Modeling Madness review that shows the markings that I have. I can scan them the next time that I hobble down stairs.

The knee is doing fine, it was scoped on Wednesday and I am working out the soreness and stiffness now.
 
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