After cleaning up the remaining minor details, such as drilling port holes, the rocket was complete as far as I could take it in NYC. I do not paint my rockets until they have been tested, with the intent of saving the bulk of the finishing time on a rocket in the case that it fails it's first time out. Once it survives an actual flight, I take the time to make it pretty. Well... as pretty as my adolescent spray paint skills can make it. :)

The next step of the journey involves getting it to the launch, because as my dad assured me, trying to get a rocket past airport security is lunacy, motors in tow or not. The only other real option is to ship it to where you are going and pick it up once you get there.

As it turned out, there were some more things I was planning on doing at the fields, which I wouldn't have to if I shipped it to Jimmy, who I will be meeting in Atlanta and driving up with he and his father. Since Jimmy already picked up my rocket box from my dad, he would be able to take care the even more last minute things, like drilling holes for shear pins, attaching the rail buttons and ground testing the electronics.

Planned Flights

If you haven't noticed, we have a flight log for every rocket here on rocketclubs.com which you can find by clicking on the name of this rocket in this article's header, and then clicking on the the icon on the right which looks like fire coming out of a rocket. Or you can just click this link. If you log a flight for a future date, the flight will be marked as planned until that date, and then it will automatically switch to the main flight log.

If you click the date of a flight on the flight log page, it will take you to a launch details page. This page has all the details of the launch, including a complete list of the motors used, projected launch date and altitude. We have a number of planned features for this page, which we will announce when they are ready.

In the meantime, please check out my planned flights, and you'll see that I'm going for a lot of firsts at ST2011, first K motor, first mile high flight, first electronic recovery system and first dual deploy. Hope to see you all there!

Now that I have solved the problem where my motor tube was too large, I can now complete the fin can!

Completing the Fin Can

As soon as I finished sanding the crap out the motor tube centering rings so I could put the parts together, I went ahead and finished it up by epoxying it all together.

The next step was to insert the motor tube assembly into the lower air frame. I used the method I learned earlier in this process and put the inner ring of epoxy in first, then slid the motor tube in half way and put a second ring around the base. This worked like a charm. I let this section dry for a few hours, and prepared for the next step in which I would put the third centering ring up near the end that would eventually connect to the rest of the rocket.

The epoxy had fully set before I started this process, and I am very glad I let it because otherwise it would have destroyed the fin can because the extra epoxy on when inserting the last centering ring caused a VERY tight fit that ended up putting a lot of pressure on the motor tube.

I had dry fit this section and planned it out fully before I ever glued the motor tube in place, so I knew better than to try and dry fit the last centering ring after the motor tube was stuck in place. At this point once you put the last centering ring in, taking it out would be almost impossible.

The basic plan goes like this:

1. EYE BALL IT, MAN, DOUBLE CHECK, TRIPLE CHECK!
2. Mark the coupler/bulk plate assembly half way with a pencil
3. Put a bunch of epoxy around the edge of the tube
4. Slide the centering ring in just over a half inch
5. Insert the coupler/bulk plate assembly, spinning it as it goes in until it gets to the pencil mark
6. Turn the entire assembly upside down and hold it in place

Attaching the Fins

Once the motor tube, all centering rings and the bulk plate assembly have dried and are firmly in place, the next step is to attach the fins. I differ from the kit instructions when it comes to fins. The instructions call for you to leave the bottom centering ring off, tack the fins in place and drain epoxy along the fins. I prefer to tack the fins in place, drill a hole next to the fins and use a baby feeding syringe to insert epoxy into a closed cavity.

Either way you have to tack the fins in place. This is easy enough, just put a nice generous amount along the fin slit and a strip along the edge of the fin which will attach to the motor tube. Then insert the fin and use tape to hold it in place. Using this method you can put all the fins on at once and be prepared for the fillets a few hours later.

The only bit of advice I have for the fillets so far is to use tape to mark off where they should end. This makes clean up significantly easier by removing the need to sand off the excess. Just make sure to pull the tape off well before the epoxy starts to harden.

One of the things that has always confused me about Public Missiles kits is that the instructions tell you to attach the nose cone by poking out the thin little circle of plastic on either side of the nose cone and looping the shock cord through it. Seriously, check out step 8 in the instructions for this kit. How I'm supposed to string a 3/4 inch nylon strap through a quarter inch hole without destroying it is beyond me.

Problem - Attaching the Nose Cone

Up to this point, building the rocket has been a pretty smooth process, with nothing more than the usual kinks of trying to fit my forearm down a 3in tube and realizing the instructions are your friend for the most part. In this case however, I think the instructions for step 8 were written for a rocket which comes with a shock cord small enough to do this, and then to avoid rewriting step 8, they just let you figure this one out for yourself. And that's exactly what we are going to do in this article!

Research

I always look first for first hand accounts of someone else doing it before me. If you can find someone else describing problems in their own words of a first hand account, you will likely find yourself in the same situations and more prepared for the problems they were not expecting.

The instructions do suggest using a kwik-link, which is just a small loop with a screw tight hole in it. In this case, I have my own first hand account. My second high power rocket ever was a Public Missiles Quasar and I purchased a kwik-link with it to solve this problem as suggested by the instructions. When trying to poke the thin plastic out with an X-acto knife as shown in the instructions, it took some work to clean it up and even once opened completely and cleaned up, the hole was still too small for the small kwik-link to fit through it! I ended up wiggling it back and forth for a minute or so until I finally forced it through and on the very first launch, the force of the ejection charge blew the nose cone clear off, tearing right through the plastic!

Another solution is to just forego the need to attach a shock cord to the nose cone at all by adding a payload bay as the top section to your rocket. If you plan to go this route, it is advisable to have made the decision before you purchase the rocket to make sure you have the extra airframe and coupler bulkhead. This solution works great for small single stage recovery projects as a place to toss an altimeter or some extra weight depending on the motor you are using.

At the November 2010 monthly club launch for Phoenix Missile Works (NAR682, TRA81) I spoke with Richard who had another idea. He had a similar nose cone and showed me how he had attached an eye bolt to hole in the center of the nose cone which was much stronger than anything I had seen before. It was more work than the other methods, but you could feel the strength of it when tugging on the shock cord.

Solution - Eye Bolt in the Nose Cone

In the story about tearing through the plastic with the kwik-link attach, the problem almost certainly boils down to me using too much black powder or some other cause than the strength of plastic hole, but I like to have as few concerns as possible when launching a rocket, and this experience kept me from wanting to try this method again.

This rocket was also designed to have the electronics in the center section. Adding another payload bay at the top was not in the original plan and the weight was distributed perfectly for larger motors. Cross that option off the list.

Since I saw the eye bolt solution I've wanted to try it out. The instructions Richard gave me involved cutting a hole in the side of the nose cone to pour epoxy into which would then be epoxied over itself and sanded back to match the original wall of the nose cone. This seemed like a lot of extra work, so instead picked up some 5 minute epoxy, mixed it and quickly but carefully crammed as much of it into the hole as possible in 30 seconds. I used enough to be sure that it would fill the small area around the nosecone when turned right side up.

Next I screwed an eye bolt into the tip, I made sure to buy one large enough that it fit tightly inside the hole, turned the whole thing right side up and held it there for 5 or 6 minutes while it all settled and reached a semi set state. Then I flipped it back over and added some more epoxy to the outside to ensure there were a firm grip on the inside and outside of the nose cone. At this point make sure to clean up the excess quickly to avoid sanding later. I let it rest standing upside down and called it finished. About an hour later, it felt almost as strong as the one Richard had shown me!