Centuri BT60 Vulcan Upscale

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JAL3

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Since I was a kid, I have always been captivated by the paper shrouded rockets like "The Point". My biggest nemesis, however, was always the Centuri Vulcan. I built lots of them but never got one to behave or even look very good:(...until I became a BAR and cloned one. It's not the best flyer in the world but it actually works which is more than I can say about any that I built in the 70s.;)

Recently, I have been in contact with Blades from TRF about his 24mm upscale and he kindly sent me the PDFs for the shrouds. After some conversation, we mentioned other scales and I mentioned that I used to be an engineer and still had a color plotter that handles media up to 5 feet wide and 300 feet long. This also means no splicing of the shrouds!:D

I tried to print first on a sheet of posterboard but the plotter did not like that. The media was too thick. I visited the local paper distributor and found 130# cardstock that was less expensive, bigger, thinner and stronger than the posterboard. I ordered some sheets and resolved to give it a try.;)

It took some trial and error but I found that landscape orientation would actually work.

Now I gotta figure out the rest of this hare-brained scheme!:surprised:

Special thanks to Blades for making this possible: your shrouds are in the mail.

Also thanks to Greg, the guy who makes my printers behave because they don't like me very much.

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Can you print up more copies to sell?

Looks like an upscale would be fun!

Keep everyone in the loop on how you are progressing!

Thanks
Les
 
Can you print up more copies to sell?

Looks like an upscale would be fun!

Keep everyone in the loop on how you are progressing!

Thanks
Les

I wouldn't mind doing a few but am afraid of getting bogged down trying to do lots. Getting to plotter to accept the media was non-trivial.

Let me get this one built and make sure everything works. I'll keep posting on this project.
 
Maybe if there was sufficient interest (and it works), one of our online vendors would consent to sell them, then you could spend an afternoon printing a few dozen copies and ship the lot to one location. sure it takes some of your time, but if it worked out you'd also stretch you rocketry budget.:D
 
Maybe if there was sufficient interest (and it works), one of our online vendors would consent to sell them, then you could spend an afternoon printing a few dozen copies and ship the lot to one location. sure it takes some of your time, but if it worked out you'd also stretch you rocketry budget.:D

I hadn't thought of that and I like the idea.:D

BTW, you may have made an enemy of Greg, my printer guy. THe HP 5500 is the most cranky of my printer herd and they are a pretty cranky lot to begin with.;)

The first thing, though, is to make sure it flies!
 
After printing out the shrouds, the first step in construction was to cut out the cardstock pieces. I cut the body shroud right on the lines and then rolled it up and kept it that way with some rubber bands so that I would have an easier time rolling the body later. The other pieces were not cut so close. I wanted to leave the fold lines visible so that I could pre-fold them before doing the final cutting.

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For the 2 wings, the tail and the airscoop, I used a ruler to fold along the centerlines and make sure the creases were sharp and straight. The ruler was then used to fold under the mounting tabs. Only then was the excess material cut away.

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Like the original, this Vulcan has a choice between 2 different style cockpits. One is simpler to construct than the other but the more difficult one is reputedly more in keeping with the overall design. I like both cockpits. On one of my normal size clones, I put both on and called it the Vulcan Trainer. I may do the same with this one but for now, I went ahead and constructed both.

The cockpits were prefoled and then cut out. White glue was used to fasten the tabs and produce the 3d cockpits.

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The after bulkhead was cut out and then a circle cutter was used to remove the center circle. The outline was then traced onto a piece of 1/4"x6"x36" balsa.

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The rubber bands were removed from around the body shroud and it was test fitted around a BT60 tube. It fit just right. An extremely small amount of glue was put on the first 3" of the tab and the two halves were pressed together. They were then pulled apart and the glue allowed to dry. The same thing was done with the after end. Then a small bit of additional glue was applied to the forward end of the tab and it was pressed together around a BT60. Alighment was carefully checked and the resulting cone was held together with my fingers for about 3 minutes. When it was dry enough that there was not risk of the seam popping, I glued the after end similarly, checking for alignment along the lenth of the shroud. The middle section was not yet glued.

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These big ones are fun, aren't they? Can't wait to do an even larger upscale of the Vulcan. I figure, (based on the scale) that you'll probably need about 2 1/2 ounces of nose weight and you should have a dead straight flight. Another bonus, you'll actually have room for a decent sized parachute in this one.
 
You may want to consider making a second printing of the fin patterns and laminating them onto the inside of the fins. Not only does it look cool, but it adds a lot of strength to the fins. A little reinforcement never hurts, especially since this bird will be flying with considerably more Ooomph than a C6.
 
These big ones are fun, aren't they? Can't wait to do an even larger upscale of the Vulcan. I figure, (based on the scale) that you'll probably need about 2 1/2 ounces of nose weight and you should have a dead straight flight. Another bonus, you'll actually have room for a decent sized parachute in this one.

I'm enjoying this one for lots of reasons.

I love the Vulcan.
I like making it big and am already having visions of 4" LOC tubes.
Making a parachute fit will be sweet. I think I'm going to use a baffle.
Best of all, I started working on this at home in the airconditioning!!!!!! (no balsa dust to tick off you know who thus far.)

Thanks again for the idea.
 
You may want to consider making a second printing of the fin patterns and laminating them onto the inside of the fins. Not only does it look cool, but it adds a lot of strength to the fins. A little reinforcement never hurts, especially since this bird will be flying with considerably more Ooomph than a C6.

That sounds like a splendid idea. I'll get Greg to run another set on Tuesday.
 
After the ends had dried, I slowly started tacking down the rest of the seam, working from front to back and using a double glue joint. By doing this, I was able to keep the edge of the shroud right on the line and, as I realized there would be a small bubble from not having everything perfectly taut, that bubble would be hidden under the air scoop to be installed later.

As the body shroud was drying, I used a cirlcle cutter to remove the inner circle from the after bulkhead. the after bulhead color plate was then glued in place and allowed to dry.

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I finally found a 34" length of 1/4" launch lug at Balsa Machining Co. It was quite reasonably priced at $1.50 but then I learned the shipping policy. There was a $6 flat fee for shipping pluss a $3 surcharge for placing the order through the mail. That would have brought the price of my launch lug up to $10.50. Instead, I bought a package of 6" lugs made by LOC from my local hobby shop and decided to splice them.

I started with 2 lugs and ran a piece of 1/4" through them to keep them aligned. I then cut out a 3" wide strip of typing paper and smeared some white glue on one end. The two pieces of lug were butted together and set on the end of the paper and the glue was allowed to dry. A toothpick was then used to smear a thin layer of glue on the unrolled section of paper and it was tightly wound about the butt joint between the two lugs. Keeping the paper tight is the key to keeping the 2 lugs aligned. When the first spilce was completed, I added another 6" lug for a total of 3.

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I printed up a second sheet of the page with the fins, tail and air scoop. I cut these elements out just as I did with the first set but a few differences. I did not pre-fold the second set. I also cut off the tabs intended for gluing. These were to serve as the "inner" surfaces.

I mated up each of the inner surfaces with its corresponding outer surface and did a bit of trimming where needed. I placed an outer surface face down on the table and then test fitted the inner suface. I wanted it to come right up to the glue tab but still allow the tab to fold around it. White glue was then applied to half the outer surface and smeared to cover it. The inner surface was set in place and pressed flat and then allowed to get tacky. When the join was stable, I applied glue on the other half and pressed the rest of the inner surface into position.

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At this point, the aft bulkhead consisted of a piece of 1/4? balsa with a hole in it and the color plate glued to its surface. I started to shape it up by using an X-acto saw to trim off the corners and remove bulk material. A belt sander was then used to shape it to the outline of the color plate.

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I started with the tailfin. A layer of white glue was applied to one of the tabs. It was then pressed into place and immediately removed and the glue allowed to dry. When dry, a bit more glue was applied to the tab and the fin was again pressed into place and held until the glue set enough not to move. This was allowed a full hour before any more work was done.

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When the one side was completely dry, the process was repeated on the other side. I waited between sides because these double layer appendages are STIFF and I did not want to displace anything.

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Well, I've got my 60 nearly finished, just have to add nose weight (I'm figuring about 2.5 ounces) and paint the aft end of the motor mounts. I used a stock Estes plastic cone, decided it would be easier than turning a balsa one. I also built two interchangeable motor mounts for it, so I can fly with both 24mm and 29mm loads. This Vulcan is definitely a beast and should look pretty impressive in the air. The family picture below also shows my first upscale, the BT55 version.
BT60 Vulcan front.jpg BT60 Vulcan bottom.jpg Vulcan family 1.jpg

Now I just have to work up the nerve to build the BT70 version you printed out for me. I might have to cluster that one. :D
 
Well, I've got my 60 nearly finished, just have to add nose weight (I'm figuring about 2.5 ounces) and paint the aft end of the motor mounts. I used a stock Estes plastic cone, decided it would be easier than turning a balsa one. I also built two interchangeable motor mounts for it, so I can fly with both 24mm and 29mm loads. This Vulcan is definitely a beast and should look pretty impressive in the air. The family picture below also shows my first upscale, the BT55 version.
View attachment 58362 View attachment 58363 View attachment 58364

Now I just have to work up the nerve to build the BT70 version you printed out for me. I might have to cluster that one. :D

That looks great. They look great. All of them!

I'm kind of worried about the joints between the appendages and the shroud. They were placed with white glue and I'm worried about shredding with a 29mm motor. I'm thinking of painting the joints on the inside with some epoxy to strengthen them. What do you think"

I got my motor mount today and put it together. That means this one is comming back to the front burner!:D

I ordered a 7x18mm cluster mount for the BT70 version. I'm also having delusions about a really big one that puts a motor mount in for each of those circles in the aft bulkhead.
 
Epoxy fillets for the fins are probably a good idea. At this scale, a little extra reinforcement certainly won't hurt.

I've got plans to make an entire fleet of different scaled Vulcans. I've already made print outs for MMX and 13mm powered ones. I'll also work up a BT50 scaled version, probably flying on 24mm. That one should really scoot.
 
I ordered a Cygnus 29mm to BT60 Motor Mount from Uncle Mike's Rocket shack to use in this project. When it came in, construction of the motor mount was simplicity itself.

The motor tube was marked 1/4" from one end. The two centering rings were then test fitted around the tube. One fit just fine and the other needed a good bit of sanding to fit around the motor tube. Once they fit, I placed one even with the 1/4" mark and the other flush at the end. The rings were then epoxied in place with 5 minute epoxy. A thrust ring was provided and epoxied into the end with the flush centering ring. When the epoxy on one side was set, I turned it over and painted in on the other, building up a good fillet on the aft ring an sealing together the thrust ring, motor tube and centering ring on the forward end. After that, it was just a matter of waiting for the epoxy to cure.

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For my upscale Vulcan project, I needed BT60 tubing longer than the 18" that comes standard from Estes. I decided to kill two birds with one stone and use a baffle for the coupler. I chose the Fliskits BAF60 Baffle since I had good luck with their BAF55 in the past.

The first step in assembly of the baffle was to thread the Kevlar thread through the provided hole in the after baffle plate. I've had trouble doing this before but this one fit just fine. The Kevlar was knotted and then passed through a notch in the outer edge of the baffle plate so that it would pass up through the baffle. The plate was secured in place with epoxy and epoxy was "painted" over the face of the baffle plate and the interior of the coupler to act as an ablative surface. When the epoxy had set, the Kevlar thread was fed through the notch in the forward plate and that was installed with epoxy as well. I spent more time waiting for the epoxy to set up than in actually putting this thing together.

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The motor mount was installed in a full length BT60 tube and the motor tube protruding just a touch from the end with 5min epoxy. When the epoxy was stiff, I set the BT down on its forward end and mixed another small quantity of epoxy. This was poured into the gap between the motor tube and the BT.

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One of the decisions I had to make was about the nosecone. I did not have the gumption to try and research getting and exact upscale copy fitted for a BT60. Instead, I bought a package of Estes BT60 cones and picked one from the two styles availible. One was a Big Bertha type that is probably a better match but I chose the ogive. I sanded down the seam and then poured in some BBs to serve as nose weight, following them with some expoxy to hold them in place. I put just a touch under 4oz, probably too much, but I wanted my 29mm motors to have to do a little work and I want to get the rocket back. I then painted the NC gloss black.

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I took the tube with the motor mount and marked it at 9" from the aft end and cut it at this point. I then took the tube with the baffle coupler and joined the two together with yellow glue. This puts the baffle fairly far back in case another has to be installed at some point as a replacement. I figured that with the noseweight I added, it should be alright. I did not cut the forward tube at this point, preferring to wait until a later step.

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I had been taking my time installing the fins, tail, scoop, etc., wanting to make sure that each component is in the exact right place. After joining the body tubes, I finally installed the last fin.

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One of the decisions I had to make was about the nosecone. I did not have the gumption to try and research getting and exact upscale copy fitted for a BT60. Instead, I bought a package of Estes BT60 cones and picked one from the two styles availible. One was a Big Bertha type that is probably a better match but I chose the ogive. I sanded down the seam and then poured in some BBs to serve as nose weight, following them with some expoxy to hold them in place. I put just a touch under 4oz, probably too much, but I wanted my 29mm motors to have to do a little work and I want to get the rocket back. I then painted the NC gloss black.

I used the same cone. I'm sure that I'll have to turn a balsa cone for the BT70 version. There's just not that many cones made in that size. If you would like one, let me know. I've got the balsa on hand.
 
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