Dual Deploy Vulcanite explanation for Peter Waithe

Hi Peter, as I said I would I have snapped a few pictures of my dual deployment vulcanite. It has been glassed, and it was my first attempt at it so forgive the crudeness of it. It has been rather extensively modified, and here we go.

The booster section first. The first thing is that this rocket uses a traditional anti-zipper design so it has a coupler on the top of the booster, which is modular so any component is replaceable. It attaches through the wall with 3 10-32 screws, which screw into the t-nuts epoxied into the inside of the coupler.

The coupler has bulkheads on each end that are stepped so to snap into the coupler. The bottom set has t nuts through it. Through the bulkheads is 2 6" aluminum threaded rods, which thread through the top bulkhead. The bottom with the threaded rods. Also I have a tube epoxied to the inside of this to hold a Walston transmitter.

So, the coupler goes over this, and the top bulkhead with ubolt screws onto the threaded rod. The whole assembly then attaches to the booster with the screws.

The ubolt attaches via quicklink and 1/8" tubular kevlar to the ebay.

The upper airframe. To describe this I will start from the ebay, which is attaches a similar method to two pieces of airframe-one above holding the parachute, and one below which slips ove the booster coupler.

The ebay itself attaches to the airframe sections via screws and tnuts like the booster coupler. The ebay needed to be a bit longer than the single piece of coupler so I cut two pieces of coupler and a 2" piece of airframe, and epoxied them together.

In the above picture, you can see the stepped bulkheads. They each have a cast eyebolt, and a 3/4" piece of dowel rod drilled to hold the small Pratt Hobbies ejection charge cylinder. The wires pass through the bulkhead, and the hole is sealed on both sides with silicon RTV. It works great...never had any sign of bleed through. Also of note is that this allows there to be no external wiring so you can prep your altimeter at home, take it to the field, load the charges, assemble the rocket, and fly it. A picture of the ebay bulkheads.

The altimeter mounts on a board. I have been using brass tubing for the threaded rod to ride through because I had it, but I think I am gong to find something nonconductive during the winter. The ends of the mounting board are notched for wires to pass around and not be pinched. The altimeter is armed via a screw switch I bought from Aerocon, which is epoxied to the underside of the carriage and accessed with a small flatblade screwdriver via a vent hole.

The nice thing is that is is extremely modular so if something breaks you can usually just replace it. It is strong...I have flown this on motors ranging from an H123 to a J570. A final picture of the ebay bolted together, and the rocket laid out.

If you have any questions let me know,

Mark Koelsch

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Comment by Mark Koelsch on June 22, 2008 at 11:03pm: Darrell, I would be willing to moderate it if that might help.

Comment by Darrell Mobley on June 21, 2008 at 11:12pm: I'll poll the other moderators. I think it would be we received.

Comment by Mark Koelsch on June 21, 2008 at 7:57pm: It might not be the worst idea. It is a somewhat complicated program. I certainly would be willing to help out on that forum if you set it up.

Comment by Darrell Mobley on June 21, 2008 at 4:19pm: I am as lost as lost can be. But I will figure it out. Maybe we need a RockSim forum on RP?

Comment by Mark Koelsch on June 21, 2008 at 1:56pm: Darrell, if you have any questions about it let me know...I have been working a fair chunk with it.

Comment by Darrell Mobley on June 20, 2008 at 3:26pm: I bought RockSim last night, so Tim should give you another update for the referral! ;-)

Comment by Mark Koelsch on June 20, 2008 at 10:23am: The last version I bought was 7. I got 8 for free from Tim Van Milligan at Apogee. I had done a bunch of work helping John Coker eliminate a lot of motors missing data files on thrustcurve.org, and Tim was impressesd so he comped me.

I do understand about getting away from computers. It is tough when it is what one does for a living.

I might try the Soller stuff a bit more, but I think I will go with the carbon and colored glass...not need to paint...just some clear coat.

Comment by Darrell Mobley on June 19, 2008 at 9:26pm: I use Soller's regular fiberglass sleeving, but have never messed with carbon or the colored stuff. I haven't built anything powerful enough to use carbon, so I stick with the least expensive solution. I believe if you used Soller's regular glass, and used their heat-shrink tube, you could get a relatively smooth surface. I don't use the heat shrink, as I can get it pretty smooth without it.

I might get RockSim, I just don't need something else to tie me to a computer. My biggest problem is getting away from the computer.

Comment by Mark Koelsch on June 19, 2008 at 9:03pm: I have used the kevlar sleeves from Giant Leap. Super tough stuff, but a pain to finish. Have you ever looked at the Carbon and colored fibergalss sleeves from Soller Composites? That is some sweet looking stuff. I could go that way for my L3, but my L3 was going to be 4" with 75mm mount, and should do 14000' on an M1297.

I love Rocksim. It has saved me tons of time, and I just like to tinker with designs. It has also allowed me to help some fellow rocketeers solve problems and come up with good performance predictions. I do recommend it, but to each their own. Then again, I am a network admin so I like to tinker with computers...just a coincidence?

Comment by Darrell Mobley on June 19, 2008 at 3:41pm: Honestly I have never purchased RockSim. Just hasn't made it onto my wishlist.

Have you ever used fiberglass sleeving? It makes glassing so simple you can do it without even getting your hands dirty! 10 feet of 4" diameter is a little over $30, so added to $20 worth of phenolic tubing, it's very inexpensive to me.