Composite Warehouse - Terminator 3

[TheTank]

I'm a sucker for a split fin design so when Composite Warehouse had a sale and I picked up a Formula 98.... I saw the T3 was also on Sale so I grabbed one as well. I didnt see any threads on the Terminator 3 so I figured I would share some build pics as it was my first rocket with a boat -tail that integrated with the rear fins and since these kits come with no instructions, I figured I would share some of my thought process while building it for any others than might be looking for info down the road.

Completed the initial wash down of all the parts and completed the initial sanding/roughing up of the various areas that need it. I laid the parts out to mock-up the build and get initial measurements for where I would need the main CR's along with motor-mount position so that I would have the proper spaces for the retainer on the back end. Upon initial layout, I realized the Aeropack retainers that I typically use would be very difficult to use and it wasn't going to give me the look I wanted on this rocket. A friend recommended a Slimline from Giant Leap rocketry so I took a look and ordered up one of their slimline threaded retainers.





Look with the Aeropack retainer. Great products, just not what I was looking for on this project.



Giant Leap Slimline retainer - Lightly sanded the inside lip of the boat tail with a dremel sanding drum and it passed through without issue. This allowed me to push the motor-mount forward allowing more space for an adequate fillet on the forward CR and gave it a nice clean look on the back end. A real nice piece.

 

[TheTank]

Once I knew the retainer was going to work, I continued to mock up and take measurements for the two forward CRs so that it would box in the forward fins and allow proper motor-mount placement to place the retainer exactly where I wanted (up in tight to the boat tail. As I could slide the boat tail over the retainer, I could measure and tack the two forward CRs with medium CA, install the motor mount with the retainer in place, then slide the boat tail over it all to check the fit before permanently gluing anything. Once satisfied with the fit, I added the fillets to the front of the forward CR and the back of the #2 CR to make I got no glue in the fin area as I was going inject the internal fillets later one anyway. I then glued in the motor mount assembly to the booster section so that the CRs aligned with the beginning and ending of the fin slots. I did trial fit in the fins during the initial mock up process as well as double checked then while gluing in the motor mount. There was definitely an uneasy feeling about gluing in a motor mount with that much tube hanging out the back of the booster. Not something I was use to seeing.

 

[TheTank]

Tacked the front fins in and started prepping to add the boat tail by measuring, test fitting, tacking and test fitting again the the boat tail CRs and the small rear coupler that centers the boat tail. These have to be glued on in a specific order working front to back otherwise you will block access to next item in line. Also, I wanted the front fins on so that as I glued on the boat tail, I could also drop the rear fins in and align them to ensure that everything was perfect.

After the fins were tacked, I installed the rear coupler first. I used the 3rd centering ring only to make sure the coupler was square to the motor mount and the body tube. Once the coupler was glued and tacked in, I installed the blind nut for my rear rail button (as I have access now) and I then moved the 3rd centering ring back to its position and put a fillet on the front side while tacking it on the back side in 3 spots to ensure the glue would not interfere with the fins. I added the 4th centering ring at my pre-determined marks and installed the retainer at this point as it is inset within the boat tail and I would not be able to access the motor mount tube easily to add the JB weld after the boat tail is on permanently.

 

[TheTank]

At this point I was ready to install the boat tail. As I planned to take the rear fins in at the same time I prepared enough epoxy for the boat tail to couple joint and the third and 4th centering rings. I added the epoxy to the outer edge of CRs 3 and 4 and to the inside edge of the boat tail where the coupler joined it. I slide the boat tail into place and "eyeballed" it at first to get the initial fit. I then took clamps and a straight piece of angle aluminum and tacked the rear fins in place (with Medium CA) while the aluminum angle held them in place and ensured alignment with the front fins. Once aligned I set it in the nose down position to cure. I was please with the results when it was done. On to injecting the fillets!

 

[TheTank]

I injected the internal fillets for the front and rear fins as well as laid up the external fillets as well. I injected West Systems 105/206 with silica to thicken it and used 30 minute Z-poxy for the the external fillets.

 

[TheTank]

At this point, the booster was complete besides adding the forward rail button, vent hole, and rear shear pins so I moved on to the nose cone and av bay. I installed my forged eyebolt in the NC plate and glued it to the shoulder with a solid fillet of 30 minute epoxy though in theory, it would not be able to pull past the coupler once installed. Once dry, I glued the coupler assembly into the NC to complete it.

The Av-bay included the vent band and two stepped bulk plates for the ends. I went with 10-32 hardware for rails and the same basic sled design that typically with is simply 1/4" ply with 1/4" aluminum C-channel for the sled rails to pass through. I laid out the electronics for redundant dual deploy on this rocket due to the weight and motors I plan to fly in it. For very little added expense, it is a nice safeguard. I felt the 3" airframe would be very tight for two charge wells so I went with centrifuge tube setups. At the time I took the pictures I was waiting on my batteries and one altimeter. I used an RR2CL and RRC2 from Missleworks along with 2, 2S 300mah 30 Lipos to power them and two screw switches from missleworks but this was the only picture I took it seems before I opted for redundant dual deploy.

 

[crossfire]

Very nice build. A snap ring Giant leap retainer would work nice also. I have always built a tail cone split fin kit starting with tail cone first than sliding main tube on it. Both ways look to work out nice. I build bottom section first because if have foamed them.

 

[TheTank]

Once the sled was done and wired up, I drilled the remaining shear pin and rivet holes, installed the kevlar harnesses from OneBadHawk recovery and the 18" drogue and 58" Main. I went with the 58" Apogee Main as I had it laying around and it fit without issue in the airframe while wrapped in the nomex blanket. At this point the rocket was complete and ready for charge testing.

I added it to the rest of the split fin fleet(with two of them waiting for paint)...

 

[TheTank]

Very nice build. A snap ring Giant leap retainer would work nice also. I have always built a tail cone split fin kit starting with tail cone first than sliding main tube on it. Both ways look to work out nice. I build bottom section first because if have foamed them.

Thanks!

I did look at the snap ring version at first. That said, knowing my clumsiness, I figured I would be dropping/losing the rings so I opted for the screw on version.

I went back and forth on working from the bottom up or the top down (thought about it for a while as this was the first one I have done with this type of setup). I was worried about getting the CRs and motor mount square in the boat tail/tail cone so I went from the top down. A lot of measuring and re-measuring but tacking it in to test definitely helped put my mind at ease before I started laying in the epoxy.

 

[crossfire]

There's no right or wrong on how to do it.

 

[mikec]

I did look at the snap ring version at first. That said, knowing my clumsiness, I figured I would be dropping/losing the rings so I opted for the screw on version.

I used the snap ring version on my Talon 2 and it's a little bit cleaner-looking, but I live in fear of losing the ring, so I think you made the right call.

Beautiful build, it came out very nicely!

 

[TheTank]

I used the snap ring version on my Talon 2 and it's a little bit cleaner-looking, but I live in fear of losing the ring, so I think you made the right call.

Beautiful build, it came out very nicely!

thanks! The way I lose things... id probably lose the ring before I got to the field!

 

[crossfire]

I used the snap ring version on my Talon 2 and it's a little bit cleaner-looking, but I live in fear of losing the ring, so I think you made the right call.

Beautiful build, it came out very nicely!

They sell extra rings. Just keep them in tool box

 

[TheTank]

Finished the av bay and charge tested. Ended up adding another altimiter, battery, and switch for a full redundant setup. RRC2L and RRC2+. 2 300mah 2S 30c lipos. Besides a little paint, its ready for flight.

 

[jd2cylman]

Finished the av bay and charge tested. Ended up adding another altimiter, battery, and switch for a full redundant setup. RRC2L and RRC2+. 2 300mah 2S 30c lipos. Besides a little paint, its ready for flight.View attachment 447481

Yer paintin the AV bay???

 

[TheTank]

Yer paintin the AV bay???

only if i get really bored...

 

[BSNW]

Yer paintin the AV bay???

I paint my sleds and av bay lids. Gives it a finished look. Once you do it, you will always want to!
Andrew

 

[TheTank]

I paint my sleds and av bay lids. Gives it a finished look. Once you do it, you will always want to!
Andrew

that’s what Im afraid of... ill want to re-do all my sleds if I do one.