The Aerotech Mirge is my first build over 45 inches and also my first documented build so any tips tricks will be welcome. This is my second mid power rocket the first was a Mega Der which is the rocket that got me back into the hobby. On this build I will be assisted by my lovely fiance. Who has really taking a liking to rocketry and this rocket. 

first step was unboxing.  We should all have this part down by now.  The rocket came from tower hobbies so there was two boxes a shipping box and then the rocket box. There was no damage to either boxes.  As I started to pull out all the pieces I did notice two of the tubes looked like they where already launched I presume this happened in the manufacturing or packing stage.  I located the instruction inside the body tube with the nose cone in it. The second body tube had the one and only decal and the third was empty.  I ran thru the instructions and then made sure that all the parts where there and they where.  Interesting side note this rocket uses two parachutes ( that is a first for me) one 22 inch for the upper section and a 30 inch for the lower section.  So with all that being said it is now time to get this build on.

The first step is to assemble the motor tube. Do to the fact that it now comes with an Aerotech alumminum motor retainer. Step one, two and four are not preformed, so the one and only step to do is step three. Step three consistes of marking the tube for the fin lock system. At the top of the instructions is a quick guide you can use to mark the location of teh fin locks, we did not use the guide, instead we used a metal ruler to preform this task. The first mark is for the back edge of the front fin lock, that mark is placed 3 9/16" from the back of the motor tube. THe second mark is for the front edge of the back fin lock it is placed at 1 1/2"from the back of the motor tube.

Attachment of the fin lock rings were very tight. The fin lock rings add structural support for the rocket so installation of them is an exercise in muscle and finess. The front ring had to have a quick beval over the MMT. I used 220 grit that I had laying around to make a beval on the back side of the fin lock. It did not take much of a beval to get it to slide into position. After the front fin lock is in place one of three centering rings is then added, followed by the back of rear fin lock this one did not need a beval and went on smoothly, followed by the rear centering ring. Next we prep the fins, removing the lower half of the fin lock tab by snapping them off, then we sanded the lower half where the fin lock tab was, using 220 grit. After this we sand the nub on the sides of each fin using 320 grit. Snap each fin into fin lock test fitting fin and fin lock for proper alignment and fit. Remove any flashing to achieve proper fit into the fin lock. Once proper fit is achieved remove fins and back centering ring,check that front centering ring is still in the proper position, then apply cement or epoxy to the front centering ring where it meets the motor tube, apply eppoxy in the area between the fin lock where fin lock an front centering ring meet, next apply epoxy to the front edge of the back fin lock where it meets the motor tube. DO NOT apply epoxy into the fin lock or the back edge of the back fin lock ring.

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Make four ¼” long cuts in the front of the motor tube 90 degrees apart. These cuts are for the gas baffle so it will fit into the tube. Next, stretch out the cooling mesh to about 6”, stuff the cooling mesh into the front of the motor tube, DO NOT glue mesh in place. Apply epoxy to 2/3 of the ejection gas baffle shoulder, then insert the baffle into the front of the motor tube. Next apply epoxy to baffle where it meets the motor tube and to each of the cuts made previously. Apply epoxy to surface of the baffle flange, place centering ring over it, screw in the screw eye into the hole at the front end of the baffle. I placed a thin drop of epoxy to prevent the screw eye from backing out, then attach the shock cord with a square knot to the screw eye.

Lower body assembly

At this point we installed the shock cord. This was in the instructions to do on the previous step. But we choose to do it with the fin installation mainly because I get lazy.  The instructions say to use a overhand knot which is a basic stopper knot. I used a figure eight instead do to its holding power and my experience with it. After the shock cord was attached you run the shock cord thru the lower body tube. As you push the MMT into the BT make sure to pull out the slack in the shock cord.  Also make sure the fin locks are aligning with the fin slots. It is rather hard to get them aligned once both centering rings are in the tube.  After I had everything inserted and lined up I went back thru and checked it by snapping in each fin.  I then took one fin off at a time  using the other two fins to hold my alignment of the fin locks. The fin that was removed got a nice and thick layer of epoxy on the fin root the entire length of fin. I then snapped it into place and waited 10 minutes for the epoxy to harden then I removed another fin and repeated the process. I treated all three fins with the same level of care. Once all fins where attached by the fin lock and the epoxy on the root it was time for some internal fillets. I have to admit I was excited about this since all the great builders are doing this. But I have to say that excitement quickly subsided. I used 5 minute epoxy for this task and for me that was a little to fast of a pace.  To apply the epoxy I used a five inch long by ½ inch wide basswood scrap I had laying around.  The fins and centering ring and pretty much everything else get a light coat of glue. Then once the back of the MMT is a gooey mess. I mean glued up to perfection. You then get to make a mess of the front centering ring by going in from the front of the tube.  The only compaction is keeping the shock cord from  getting glue on it. I stood the rocket on the fins and attacked the centering ring from a vertical axis. This worked out the best I started trying on the horizontal but found it  way  easier  on the vertical. After that is all in tip top shape. You lightly sand the outside of the body tube around the launch lug slot. Once sanded apply glue to bottom of lug attach it to body tube. And that completes the lower body tube. And it should look somewhat like a rocket. Now if I can only put mine on slime fast because it defiantly gained some weight. ( but it still looks great)

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Alright let’s get this bad boy finished up.  This is where everything comes together really fast. Pretty much it is just gluing the rocket together. At this point the rocket has been in this configuration already when we got it out of the box and assembled it to see how big it was.  But this time we are only going to add epoxy. First things first, the screw eye needs to be screwed into the bulkhead. Run the screw eye all the way down and I added a drop of epoxy just to make sure.  Once that is done tie the shock cord to the screw eye I used a figure eight again.  Now it is on to the fun stuff.  Take a coupler mark it at 3 inches. Then sand the bottom 3 inches of the coupler. Epoxy and slide it into the bottom tube. Next up take the last coupler mark it once again at 3 inches this time lightly sand the whole coupler. Then epoxy it into the first and second body tube. Assuming you are counting from the nose cone down. Once that is all dried up epoxy the nose cone on. To epoxy the coupler into the body tube run a bead of epoxy about one inch in from the end of the body tube then slide the coupler in. I like to twist the coupler to spread out the epoxy and get an even coat. Once that is done it is on to paint. Unfortunately it is way too cold here to even think about painting. So I guess I will see you all this spring.