BT70 Centuri Vulcan Upscale [Archive]

JAL3

26th January 2009, 01:59 AM

Having built 2 clones of the Centuri Vulcan and a BT60 based upscale with a 29mm motor mount, I decided that BT70 was the next logical place to try and build a member of the Vulcan family. In a bid to do something a bit different, though, I decided I wanted to use a cluster. I finally settled on a 7x18mm mount and chose to try it with the motor mount produced by Fliskits.

JAL3

26th January 2009, 02:03 AM

The first step in construction was to select one of the BT20 motor tubes and designate it as the central motor. The single provided thrust ring was then glued flush with the end using yellow glue.

JAL3

26th January 2009, 02:09 AM

The kit also came with 6 tube couplers. Each was marked at 1/4", the depth of the thust ring, and was inserted up to the mark in the remaining 6 motor tubes.

JAL3

26th January 2009, 02:13 AM

The six outer tubes were then separated into three pairs. Each pair was glued together along the length of the motor tube with yellow glue. This was done on a flat surface and butted up agains a steel rule to ensure straightness.

jflis

26th January 2009, 01:09 PM

Looking good. I will be most interested in seeing the rest of this build and how this engine mount gets integrated into the Vulcan upscale!

Blades

26th January 2009, 01:32 PM

JAL3

26th January 2009, 02:25 PM

Looking good. I will be most interested in seeing the rest of this build and how this engine mount gets integrated into the Vulcan upscale!

Thanks.

I'm still thinking about the mount. When I started, I assumed it was a "slide into the BT" like everyone else mount. I didn't realize it only goes in as far as the tube couplers.

After I get the parts printed out, I'm going to play around with them and see how it fits through the aft bulkhead. SOmething will be figured out.

JAL3

26th January 2009, 02:28 PM

John, you're the man!! This one should look particularly impressive in the air. I haven't started mine yet, mostly because I haven't decided on an engine mount yet. I'll be eagerly awaiting reports on how yours does. In the interim, though, I have turned out a BT5 downscale and a BT50 upscale. :D

I was thinking last night that I needed to do some downscales.

Heck, I want to build a big family from MMX right up to 36" sonotube. My printer's not that big though.

Blades

26th January 2009, 07:46 PM

I was thinking last night that I needed to do some downscales.

Heck, I want to build a big family from MMX right up to 36" sonotube. My printer's not that big though.

I'll be doing a MMX version to round out my family. I'll also add an upscale of the black sheep, Solomoriah's Black Vulcan (probably a BT55 upscale).
The BT5 version flies pretty well on a A3-4T, It's a little squirrely in the air, but that's kinda par for the course.

JAL3

26th January 2009, 09:25 PM

I'll be doing a MMX version to round out my family. I'll also add an upscale of the black sheep, Solomoriah's Black Vulcan (probably a BT55 upscale).
The BT5 version flies pretty well on a A3-4T, It's a little squirrely in the air, but that's kinda par for the course.

I've got the PDFs for the blackie and will get around to that one some time.

What doe you use for paper in the MM? Is it just regular copier paper?

jflis

27th January 2009, 03:54 AM

Thanks.

I'm still thinking about the mount. When I started, I assumed it was a "slide into the BT" like everyone else mount. I didn't realize it only goes in as far as the tube couplers.

After I get the parts printed out, I'm going to play around with them and see how it fits through the aft bulkhead. SOmething will be figured out.

Yeah, the problem there is that you can't fit 7 BT-20's inside a BT-70...

rokitflite

27th January 2009, 04:06 AM

Yeah, the problem there is that you can't fit 7 BT-20's inside a BT-70...

OOOOOOH... I was wondering about those long couplers coming from the front of the mount! Cool solution to a simple problem :D.

JAL3

27th January 2009, 04:15 AM

Yeah, the problem there is that you can't fit 7 BT-20's inside a BT-70...

My thoughts right now are to install the mount as per directions in the BT 70 and just have the cluster protruding through the bulkhead.

My alternative thought was to run the BT70 all the way through the bulkhead and then connect the mount, letting this rocket have a possible cool looking set of tailpipes.

I like the second idea but would be worried by the significant shift aft of the CG.

JAL3

27th January 2009, 04:25 AM

After the tube pairs had dried overnight, I began the process of mounting them to the central motor tube. This was simply a matter of smearing glue on the central mount at the approximate locations where the outer tubes would contact them and then pressing the outer tubes in place. I made sure that all tubes were in agreement in terms of fore and aft and glued the pairs on. After they were in place, I gave the assembly a wrap of masking tape to keep the sides tangent while the glue set up.

jflis

27th January 2009, 01:27 PM

OOOOOOH... I was wondering about those long couplers coming from the front of the mount! Cool solution to a simple problem :D.

You can thank Bob Alway for that :) A long time ago, on a range far, far away, Bob discovered that the width of 3 BT-20's was the same as the OD of the BT-70 (2.208" vrs 2.217", very close).

That being the case then the inside wall of the two outer BT-20's must match the ID of the BT-70... Truly an elegant solution :)

Blades

27th January 2009, 03:15 PM

I've got the PDFs for the blackie and will get around to that one some time.

What doe you use for paper in the MM? Is it just regular copier paper?

I'll be using 65 lb. cardstock for the MMX Vulcan. Should work pretty well.

JAL3

27th January 2009, 03:19 PM

I'll be using 65 lb. cardstock for the MMX Vulcan. Should work pretty well.

I guess I'll try that. I spent some time last night changing the color scheme on the shrouds of the MMX version found on the MMX Yahoo group.

Thanks.

Micromeister

27th January 2009, 04:17 PM

JAL3

27th January 2009, 05:05 PM

The Micro Vulcan version flies very well: I believe I printed my first one on 110lb cardstock, I'll have to check.

I'd like to do a Bt-60 version sometime, do you have the shroud layouts that can be printed on a home type computer. I think I'm limited to 8.5 x 14 cardstock sheets.

The shrouds I used on the BT60 were just upscaled by the appropriate factor and printed out on my old engineering plotter.

We started to do the same thing with the BT70 this morning and it got 90% through the first sheet when it decided to start being tempremental. Its giving "replace print head" messages and I just replaced them not too long ago.

This printer has long needed an exorcism but I can't find a language it understands. Now I'm waiting for the tech guy to call.:(

JAL3

29th January 2009, 04:19 AM

I started to print out the shrouds. I made a few changes to the color scheme and sent the first page to the printer. I was quite pleased until right at the end when the blue stared fading out. I checked and the system said I was low on cyan and light cyan so replaced them both. Then the color started fading even more and I started getting "Change Printhead" errors. I just replaced the things not too long ago so I have to wait for the techie to come out and check it out.

THis has ALWAYS been the most tempramental printer!!!!:mad:

JAL3

29th January 2009, 04:25 AM

When the glue on the cluster mount had dried, I took off the tape and inspected the result. It seemed fine to me but I wish I had a piece of BT70 lying around.

JAL3

29th January 2009, 04:31 AM

The kit has no "centering ring" per se, instead it has 6 little pieces which, when arranged in a circle, suggest a ring with the innards cut out for the motor tubes. Each piece is fitted between a pair of the outer tubes and glued to the coupling tubes with the edges resting on the motor tubes below. They are intended to help block ejection gasses and, presumably, form an after bulkhead for the BT70 into which they will be inserted. To my delight, they fit just fine and were secured with yellow glue.

JAL3

29th January 2009, 04:36 AM

Peartree

29th January 2009, 01:46 PM

Had a similar thing with a baffle I built this fall. If you're concerned, just glom some yellow glue in there and plug it up.

jflis

29th January 2009, 01:47 PM

I do have a question for Mr. Flis.

I noticed when looked at the end, there are still cavities in the interior through which ejection gasses can escape. I did not see anything in the instructions about sealing these. Did I miss something or is it not something to worry about?

John,

Those gaps are nothing to worry about. If you are concerned a simple drop of white glue would fill them nicely. The big gaps (when installed) are the ones blocked by those little ring segments, as you commented.

I take it the assembly of this mount went well? It was a great idea from Bob Alway and I love the way the accessory kit came out :)

Continued good luck on the Vulcan build!
jim

JAL3

29th January 2009, 02:11 PM

Had a similar thing with a baffle I built this fall. If you're concerned, just glom some yellow glue in there and plug it up.

My first thought, assuming I needed to do something, was to solve the issue in the same way instructed for the Starlight Seireron 3. Some glue soaked wadding tissue was stuffed into the cavity.

What it really came down to, though, is not having a feel for the mass flow involved. I looked and saw the escape path for the gasses but really didn't know if it was significant or not. There was also the very real possibility that I missed something in the instructions. I do that too often.

JAL3

29th January 2009, 02:13 PM

John,

Those gaps are nothing to worry about. If you are concerned a simple drop of white glue would fill them nicely. The big gaps (when installed) are the ones blocked by those little ring segments, as you commented.

I take it the assembly of this mount went well? It was a great idea from Bob Alway and I love the way the accessory kit came out :)

Continued good luck on the Vulcan build!
jim

As I told Peartree, I really didn't have a feel for the significance of the gaps and there was the real possibility that I missed something in the instructions.

I think it was an elegant way to fit 7 tubes in the BT70. The build was easy and I look forward to actually flying it.

Handeman

30th January 2009, 03:46 AM

JAL3

30th January 2009, 03:52 AM

I've never build a seven motor cluster, but personally, I would not leave an opening for ejection gases on purpose unless the kit instructions specifically said to do so. I would plug any gap that I could. The glue soaked tissue is the way I would go.

That's my inclination too. THere's just a little part of me that wants to see what happens stock but I think more of me wants to rest easy that the chute comes out when its supposed to do so.

My history with Vulcans is pretty marginal to begin with.

Pantherjon

30th January 2009, 03:21 PM

JAL3

30th January 2009, 05:55 PM

I would think that with 7 ejection charges going off that the little bit that may escape from those gaps would be pretty negligible and the chute should be deployed no problem..That is provided the nose cone isn't on terribly tight.;)

You would think, wouldn't you?

You're almost certainly right. My thought train was along the line of of this: I don't have a feel for the size of the charges involved; I have experienced a pretty wide margin in delays like an A8-10 marked as an A8-3 and an F12-0 marked as an F12-(something much bigger than 0); most of all though, if there is a critical path to failure, it leads right over ME (I have the tread marks to show for it).

I really don't think those little holes are going to be a problem. I will continue to think that way right up until the moment when they (or something like them) do become a problem and bite me in the backside.

I guess it depends on whether I'm an optimist of a pessimist.

The optimist believes we live in the best possible world.:)
The pessimist is afraid that the optimist might just be right!:eek:

Thanks for the input.

rokitflite

30th January 2009, 07:33 PM

Shoot... I'd plug the holes AND put motor hooks on the mount!

jflis

31st January 2009, 02:42 AM

Shoot... I'd plug the holes AND put motor hooks on the mount!

Lordy! 7 motor hooks would have doubled the price of the darned kit itself!

Peartree

31st January 2009, 02:45 AM

Lordy! 7 motor hooks would have doubled the price of the darned kit itself!

Aw heck Jim, that's what old windshield wipers are for...

rokitflite

31st January 2009, 02:50 AM

Aw heck Jim, that's what old windshield wipers are for...

Jim's right, they are not cheap... I did go to a junk yard though and got 60 strips of the stuff for $0.00.:D

JAL3

31st January 2009, 03:40 AM

Well, I decided to take the ultra cautious approach.

I tore off bits of wadding and tried to stuff these into the cavities. I was approaching this from the forward and and found it very difficult to manipulate the tissue down between the motor tubes. Then I realized that the other end was easily accesible and turned over the mount. Doh!

I stuffed a piece of glue soaked wadding tissue into each of the cavities and then sealed it with more white glue. After a bit of shrinkage, I added a bit more glue.

Peartree

31st January 2009, 12:25 PM

Jim's right, they are not cheap... I did go to a junk yard though and got 60 strips of the stuff for $0.00.:D

This is sad and I know it but...

I always take a quick look in the trash cans outside when I visit the Auto parts store. If it has rained recently they are often chock full of old wipers...

Pantherjon

31st January 2009, 02:00 PM

This is sad and I know it but...

I always take a quick look in the trash cans outside when I visit the Auto parts store. If it has rained recently they are often chock full of old wipers...

No, not sad...It's called being 'frugal' ;)

rokitflite

31st January 2009, 05:32 PM

There is a "pull your own parts" junkyard near me that I went to for a piece for my Jeep. As I was walking in, I thought about the whole wiper blade thing. I asked the guy how much they charged for used wiper blades. He said $1.00. I was amazed and continued with "Not the whole assembly, JUST the rubber portion.". Again he said $1.00. I could not believe this so I went futher with "For the 15 year old, hard, dry-rotted, stuck to the window, rubber portion?"... Yep, $1.00. So, as I walked around looking for the hood release for my Jeep, I simply snapped the plastic ends off of the Ansco blades I came across and pulled the metal strips neatly out and put them in my parts box... I ended up with like 60 strips. I then got the part for my Jeep and walked back up to the front office. When I got to the check out stand I emptied all of my parts, strips included, out for the guy to price. He looked at everything, said $10.00, I paid and was on my way.:rolleyes:

Handeman

31st January 2009, 08:01 PM

I would think that with 7 ejection charges going off that the little bit that may escape from those gaps would be pretty negligible and the chute should be deployed no problem..That is provided the nose cone isn't on terribly tight.;)

It would seem like there would be seven charges going off, but with the holes in the tube the pressure will bleed off fast, I wouldn't bet you ever get more then two charges to go off close enough together to actually add their forces together.

I would build it with the assumption that one motor has to do the ejection.

JAL3

2nd February 2009, 03:13 AM

It would seem like there would be seven charges going off, but with the holes in the tube the pressure will bleed off fast, I wouldn't bet you ever get more then two charges to go off close enough together to actually add their forces together.

I would build it with the assumption that one motor has to do the ejection.

That's the assumption I'm working under.

JAL3

2nd February 2009, 03:17 AM

I decided to use a Fliskits baffle as both a tube coupler and a shock cord anchor. Accordingly, I started assembling one. I got the lower baffled plate installed and coated it with yellow glue to form an ablative layer.

MarkII

2nd February 2009, 09:15 AM

Yeah, the problem there is that you can't fit 7 BT-20's inside a BT-70...
You can't?!?!? :eek:

BTW, as you can see, you don't need 7 motor hooks for PMR.

Mark \\.

JAL3

3rd February 2009, 04:38 AM

The baffle was finished off today. The upper plate was slid into place and the Kevlar threaded through the notch. An ablatice layer was added here too.

jflis

3rd February 2009, 01:41 PM

The baffle was finished off today. The upper plate was slid into place and the Kevlar threaded through the notch. An ablatice layer was added here too.

I'm trying to visualize where the baffle is going to be in this rocket... How much space are you going to be able to have between the top of the engine mount and the bottom of the baffle?

I ask because it is always recommended that you keep the baffle as far from the motor as possible, and with a cluster this is even more important. I fear that you may burn the baffle through very quickly if it is too close to all those ejection charges...

Thoughts?

JAL3

3rd February 2009, 03:35 PM

I'm trying to visualize where the baffle is going to be in this rocket... How much space are you going to be able to have between the top of the engine mount and the bottom of the baffle?

I ask because it is always recommended that you keep the baffle as far from the motor as possible, and with a cluster this is even more important. I fear that you may burn the baffle through very quickly if it is too close to all those ejection charges...

Thoughts?

You may be right. I used a baffle to join the tubes in my BT60 Vulcan and it was not able to fully protect the chute. That was with a single 29mm motor.

I do not yet have the tubes and am waiting on the printer guy to check the printer for making the shroud. It will definitely be longer but, in truth, I have pretty much followed the "it'll all work out in time" approach so far.

When I get the tubes and the schroud cut, I will better be able to guess where I will put the baffle. Since it is short compared to the diameter, I'll probably use a regular coupler tube to do the joining and move the baffle forward.

If I remember right, the baffle in the 60 version was to act as a shock cord mount as much as anything else. I had the motor mount installed in the aft tube and the remembered I hadn't anchored the Kevlar.

JAL3

14th February 2009, 04:32 AM

When the motor mount was done, it sat and waited for a while until I came up with some BT70 tubing. When I got it, I was apprehensive about the fit. The idea from Fliskits seemed good, almost too good to be true. It was true. The mount slipped in easily and was glued in place with yellow glue.

jflis

14th February 2009, 01:30 PM

JAL3

31st May 2009, 05:51 AM

I started to print out the shrouds for the BT70 Vulcan on a big HP plotter on heavy cardstock back in February. My plotter has always been grouchy about thick media and this time I pushed it too far, damaging 2 of the print heads. The cyan and yellow would only work intermittantly and I could not get shrouds I was happy with.

JAL3

31st May 2009, 05:55 AM

I could not justify the cost of replacing the printheads until a project came along for the church and I got it done. I also decided to print on band paper and laminate that to the heavy stock. The colors came out vibrant and great.

JAL3

31st May 2009, 06:01 AM

With shrouds that satisfied me in hand, I began to cut them out. I then put a small amount of white glue on the back of then, screeded it across the whole surface and mounted it to the heavy stock, smoothing it out as I went.

JAL3

31st May 2009, 06:05 AM

This went on for quite a while.

JAL3

1st June 2009, 06:29 AM

The laminated shrouds had a day to dry and I was disappointed to see that some significant wrinkles crept in despite the care I had tried to take earlier. I figured they were wrinkles I could live with and began to cut the individual pieces out.

JAL3

1st June 2009, 06:35 AM

The laminated shrouds were quite a bit stiffer than the plain cardstock. This should help to strengthn things a bit but it makes rolling the main shroud more difficult. I decided to roll it as tightly as I could and let it sit that way for a week while I was to be out of town. I am glad to have finally found a use for some of those rubber band type shock cords that come with some kits!

JAL3

8th June 2009, 05:35 PM

Leaving the body shroud rolled up for most of a week did help. When I got back home, it wanted to stay curled up. I gingerly test fitted it along the tab and then applied some white glue at the aft end and pressed the sides together. I then took a small plastic clamp to hold it more or less in place while I messed with the forward end. I put some white glue on that and clamped it as well and turned to making fine adjustments in alignment. I did not glue the middle part of the shroud at this point.

JAL3

9th June 2009, 02:18 AM

The next day, I tackled gluing down the middle portion of the shroud. I needed something besides me to hold it shut while the glue set. I decided to place the glue and press the sides together. I then let them "expand away from each other for a few moments while I got set up for my next step. I had a long wooden dowel, bigger than a BT60 but smaller than a BT70 and pushed that through the inside of the shroud from one end to the other. I then laid a piece of 1x4 along the seam on the outside. Clamps were used to hold the 1x4 to the dowel and keep the middle pressed down.

JAL3

9th June 2009, 02:29 AM

As the seam on the shroud began to set up, I began considering the fins again. Since the colored paper had been laminated onto the heavy stock with white glue, they were quite stiff; much more so than regular card stock. I began to form the first fin by trimming away all the material up to the folding tab on either side. I did leave the extension lines marking the fold location in place at this time, though. A long steel ruler was then taped into place on the back side of the fin with one edge aligned with the fold line. When I was sure that the ruler would not move, I used it as a stiff edge against which to fold the tab. The procedure was then repeated on the other side. The central fold was accomplished similarly and then the excess material was trimmed from either end.

JAL3

10th June 2009, 02:01 AM

For the after bulkhead, I used a piece of 1/4" balsa. I cut the cardstock bulhead out and smeared some white glue alsong the back. I then placed it on the balsa and applied some clamps to keep it from curling.

JAL3

10th June 2009, 02:09 AM

When the glue was dry and the clamps removed, I still had quite a bit of material to remove. When I built my BT60 clone of the Vulcan, I removed most of that with an X-acto and then finally remembered the belt sander when there was not too much left to do. This time, I went straight to the sander and, for some reason, noticed the disk and decided to give that a try. It was the right choice. I could set the piece on the little shelf and gently feed it into the disk sander, stopping when I got to a line. It was the best one of these things, and the easiest, I had produced to date.

JAL3

10th June 2009, 02:25 AM

Cutting out the central circle was not so simple. I used the brute force approach with an X-acto knife and the results were fairly rough. I cleaned up the rough edges with sandpaper and then test fitted the BT70 body tube.

JAL3

10th June 2009, 02:30 AM

The bulkhead was then test fitted in the body shroud but not glued at this point.

JoeG

13th June 2009, 12:48 PM

I have built several clusters in 24mm and larger and always seal the gaps in between with the glue soaked wadding.

Most of my seven motor clusters have been D sized and I only use three motors with ejection charges the rest being plugged. With my luck each engine would have just enough difference in delay to let the gasses pass out the back and end up having a lawn dart.

I do realize that the gaps or holes are bigger the larger the diameter the motor and I'm sure Jim is right that it doesn't matter with this one. But this process takes little time and being slightly anal I would seal them anyway.

My experience is that if your rocket is on the pad and you are wondering, "Maybe I should have....." Then yes you should. :D

Joe

JAL3

13th June 2009, 11:15 PM

JAL3

19th June 2009, 04:31 AM

In previous Vulcans, the motor mount had not extended much aft of the bulkhead. In this one, however, I was going to let the full length of the mount protrude. With that in mind, I decided to go ahead and paint the aft portion of the body tube/motor mount. I set it up in the booth and primed it with 2 coats of white.

JAL3

19th June 2009, 04:34 AM

When that was dry, the rear end got 2 coats of hammered silver.

JAL3

15th July 2009, 05:35 AM

I knew I was going to need 2 lengths of BT70 for the length of the shroud. When I test fitted the tube with the motor mount and noted the location of the coupler/baffle, I realized that packing a chute would be a tight matter in the space left to me for the upper tube. For that reason, I inserted a mandrell and trimmed off about 5" of the tube with the motor mount.

JAL3

15th July 2009, 05:37 AM

A ring of yellow glue was then swabbed around the cut end of the body tube and the baffle was inserted.

JAL3

15th July 2009, 05:41 AM

When the glue had dried sufficiently, another ring of glue was applied in the end of another BT70 tube and the 2 tubes were joined together.

JAL3

15th July 2009, 05:45 AM

The extended body tube was fit into the aft bulkhead so that the cluster mount protruded from the rear end. The tube and bulkhead were then fitted into the shroud and the forward end was marked where it poked through.

JAL3

15th July 2009, 05:47 AM

The tube was then removed and cut down to length.

JAL3

15th July 2009, 05:54 AM

JAL3

15th July 2009, 05:56 AM

I wanted to use an internal launch lug on this rocket since doing so had served me well on my original Vulcan Clone and on my BT60 upscale. Looking around my shop, though, I had only 2 6" pieces of 1/4" lug. I tried using some MMX tubing but the BT2 would not fit, the BT2.5 was very tight and the BT3 had a lot of slop in it from being too loose. I was trying to remember from where I had obtained my previous 6" lengths with the plan of splicing sufficient lengths together to run the length of the tube when I realized that the loose fit of the BT3 over a long distance would not be a problem. With that in mind, I joined 2 pieces with masking tape.

JAL3

15th July 2009, 05:59 AM

The super lug was trimmed to the length of the body tube and then a line was run the length of the tube. Yellow glue was applied along the line and the lug was pressed into place and held there to dry with the application of some tape.

JAL3

23rd July 2009, 05:07 AM

The central tube, bulkhead an lug were all test fitted to make sure that everything would line up as intended. A batch of 15 minute epoxy was then mixed to put it all together. I used a brush to paint a ring around the forward end where the BT would emerge and also painted some around the junction with the motor mount. Things were then slid back together and eased into place. I was going to use the remaining epoxy to "paint" the aft bulkhead into the shroud and firmly fix the motor mount but it decided to suddenly set up on me as I was about to make the first brush stroke. It was ugly.

I quickly threw the post away and opened my big can of ethanol to try and clean up some of the mess while it was still semi-soft. That being done, I mixed another batch and quickly pained things into place.

JAL3

23rd July 2009, 05:10 AM

I took the occasion of letting the epoxy set up as an opportunity to tie a long piece of sewing elastic to the Kevlar. The knot was fixed with some white glue.

JAL3

23rd July 2009, 05:14 AM

The closure of the shroud around the body tube at the front end was not perfect. To rectify matters, I smeared some white glue into the gaps and pressed the shroud down. Holding it down got old quickly so I held it in place to dry with some masking tape.

JAL3

23rd July 2009, 05:18 AM

I started the process of mount the first fin by taking down one edge with white glue. It was not my intention to rely of the white glue except as a temporary expedient.

JAL3

23rd July 2009, 05:22 AM

Letting the tacking of the first edge of the first fin dry gave the the opportunity to consider the cockpit canopy. I decided to go with the easier version, cut it out, folded it and glued it into shape, again using white glue.

JAL3

26th July 2009, 11:42 PM

When the glue sealing the shroud to the forward end of the BT had a day or so to dry, the tape was removed and the shroud was indeed better adhered to the tube. A little trimming still needed to be done to make things look better and neater but the main goal had been achieved.

JAL3

26th July 2009, 11:47 PM

Whereas in my previous BT60 upscale of the Vulcan, I had just used a plastic Estes nose cone that was "close enough", this time I wanted to do it right. I contacted Gordon Agnello of Roachworks and he turned a custom balsa cone for me. It was beautifully done and, being justifiably proud of his work, it had his signature on the tail end.

JAL3

26th July 2009, 11:51 PM

I hardened and sealed the NC by drizzling on a coating of thin CA and letting it harden. When hard, I gently sanded it with some #400 sandpaper.

JAL3

27th July 2009, 05:54 AM

Allowing the CA to fully cure on the nose cone let me turn my attention back to the installation of the fins. The first had already been tacked on and now it was time to do the same with the second one. Again, white glue was used at this stage just to get the fin into place.

JAL3

27th July 2009, 06:02 AM

Wrestling with the fins gave plenty of time for the CA to dry on the NC. The NC was then sanded with #400, taken to the booth and primed with 2 coats of Kilz. After a day to dry, the primed NC was sanded again with #400.

JAL3

27th July 2009, 06:10 AM

The vertical tail fin was applied in the same manner as the two wing fins. It was tacked into place with white glue.

JAL3

27th July 2009, 06:14 AM

The NC having had a day to dry and been sanded was taken to the booth and given 2 coats of blue.

JAL3

27th July 2009, 06:17 AM

When dry, the painted cone was tied into the elastic of the shock cord and fitted for the first time into the body.

JAL3

27th July 2009, 06:22 AM

The air scoop on the ventral surface of the rocket was applied with white glue in the manner of the tail and wings.

JAL3

18th August 2009, 04:39 AM

When all of the paper fins, tails, scoops and cockpits were in place with white glue, I wanted to make sure they stayed in place. It was never my intention to rely just on the glue. With that in mind, I mixed some 15 minute epoxy and used a brush to reinforce all of the seams. I did this twice, building up a pseudo-fillet in each case. I was also kind of messy and drizzled epoxy where I did not want it.

After fuming for a while, I thought I could make the blunder work to my advantage. I was using the same stock for the shrouds that I had used for my BT60 upscale but the distance between support is greater in this one. Its different enough that I worried about the integrity of the shroud. Not having very much epoxy experience, I decided to paint the entire shell in the hopes that would stiffen it up and protect the dye from the transfers.

Doing that was a long process. Even the 30 minute epoxy seemed to be curing in only about 8 minutes so I wasted a lot in the early stages. I also didn't control blobs as well as I would have wished. From a distance, though, it does have a glossy appearance and doesn't look too bad.

JAL3

24th August 2009, 02:50 AM

As this project finally began to wind down, I realized that the issue of nose weight was one that was going to come back and bite me. Since I don't do RocSim, I took a qualitative as opposed to quantitative approach. I knew what worked in my BT60 upscale and have the sense that it was a bit more than needed. With that in mind, I decided to try going with about the same amount in this version.

Since this one has a balsa nosecone instead of a hollow plastic one, the epoxy embedded BBs were not going to do it. I went to a hardware store and bought 2 large diameter washers that massed about the same as the BBs. The eyescrew was removes and a bed of epoxy was smeared on the base of the cone, making sure that it went into the screw hole. A washer was then set in place on the epoxy and the screw inserted again.

JAL3

24th August 2009, 02:55 AM

A bit more epoxy was mixed and slathered on the top of the first washer. The second was then set in place on top of it. The epoxy had not fully cured and a few drops more were mixed and used to fill the central cavity of the washers and lock the screw into place.

JAL3

25th August 2009, 12:08 AM

The epoxy on the weights got a day to dry and then the cone was tied into the elastic.

JAL3

25th August 2009, 12:13 AM

That means that the Big Blue Vulcan is ready to take to the air!

JAL3

11th January 2010, 03:07 AM

The Big Blue Vulc sat around from August to January after being finished without ever getting to fly. I wanted to make sure that all the motors of the cluster lit off so I wanted to use the new Quest igniters. I just kept putting off the ordering of them. I finally ordered some just before Christmas and received them just in time for my Club's January launch.

I installed a nomex protector and a 24" nylon chute and then began to prep the motors. I decided to use the new Quest long burning C6-3s. They seemed to be a little fatter than the older European Quest motors and they fit snugly into the mount. They were tight enough that I was not worried about friction fitting. The Quest igniters were nice also and their design made twisting the leads together nice. The plastic straws that protect the pyrogen were supposed to be used as plugs. I found that they did not fit the nozzles too well until I took an X-acto and sharpened the ends a bit. Then they worked fine.

JAL3

11th January 2010, 03:12 AM

When I got things set up at the pad, I warned everyone that this was a heads up flight. It looked good sitting there and I was eager to press the button.

JAL3

11th January 2010, 03:16 AM

At ignition, it was looking good. All 7 motors seemed to have lighted off and the Big Blue Vulcan rose off the rod.

JAL3

11th January 2010, 03:22 AM

The flight looked good early on. Their was no wobble as is common with my original Vulcan or my BT60 upscale. It did, however, begin to tip over. This occurred during the powered phase of flight.

JAL3

11th January 2010, 03:25 AM

I got a sick feeling when I decided that it was definitely pointing downward and I could still see flames coming out of the motors.

JAL3

11th January 2010, 03:31 AM

When the motors did burn out, I waited anxiously for the ejection charge to save my months of work. I wondered if maybe some C6-45s had been labeled as C5-3s and it kept plummeting downward. It then disapeared behind the GSE truck and I was delighted to hear Todd exclaim that he had seen a good ejection. He neglected to mention immediately that the ejection took place AFTER impact with the ground.

JAL3

11th January 2010, 04:31 AM

An examination of the carcass was instructive. All 7 motors did ignite and it took off well enough. It just could not stay oriented vertically. There was not enough thrust. Later in the day I had a similar experience with another rocket flying on a Quest C6. It too seemed underpowered. Immediately afterward, that same rocket behaved wonderfully on an Estes C6. Having a bigger spike might have saved the Vulcan. A better option, though would have been to use a larger motor mount.

The motor mount was the only part of the rocket to survive unscathed. The nose cone was dinged up pretty well and the body tube was crumpled at the forward end. It was not worth repairing and I gave it to an excited boy from my club to fool around with.

Peartree

11th January 2010, 01:15 PM

Sorry to see that John. She was sweet to look at.

rokitflite

11th January 2010, 04:41 PM

JAL3

11th January 2010, 05:01 PM

Sorry to see that John. She was sweet to look at.

I'm disappointed, of course, but not too much. I learned plenty both in terms of dos and do nots.

JAL3

11th January 2010, 05:03 PM

Yeah... The Quest long-burn C6s really only burn like a C3 or 4. Nice in light weight, streamlined models, not so in a big draggy model. Its like you flew it on a 60 Newton F20... Not quite enough "umph". Sorry:( It was a cool looking model a long time in the making.

That's one of the lessons I learned. I got plenty of experience with the newer C6s that day. They did wonderfully in some and pretty bad in the heavy ones. I was surprised at how bad it did in the Quest Super Eagle but I guess that rocket was designed with the older motors in mind.