I labeled the parts so we are on the same page with naming. The coupler is glued into the payload body tube. It forms both the slip fit coupling to the fin can and it acts as the AV bay. To assemble the rocket, the pyro charges for deploying the main are mounted on the AV bay top plate which is made from a couple of bulk plates. The top, with the red connector and threaded rods, is then slipped into the payload tube until the bulk plates rest on the top of the coupler and the rods and red connector extend out the bottom of the coupler. The red connector is plugged into the mating red connector on the Raven/Power Perch and the black connector on the AV bay bottom plate is plugged into the mating black connector on the Raven/Power Perch. I color coded the connectors so I would connect the Raven the right way around every time and not mix up the apogee and main pyro charges. The rocket drifted 2.3 miles when done right, if the main had come out at apogee it would have drifted much farther.
The Raven/Power Perch is slipped into the coupler and the bottom is placed over the threaded rods and secured with wing nuts. Note that this can be a bit fiddly as the rods are easily pushed out of reach if they aren't aligned with the holes in the AV bottom plate. It would help to put nuts on both sides of the rods at the top plate to help hold them in place. I didn't have room for another nut but I may try a thin C-clip or a dab of glue. Also remember that I had to modify both the Power Perch and the coupler to get the Power Perch to fit into the coupler. The pyro charges for the apogee separation are mounted on the AV bay bottom plate.
The harness between the AV bay bottom plate and the fin can is neatly packaged and placed in the fin can and the coupler is slipped into the fin can. The harness between the AV bay top plate and piston is neatly packaged and slipped into the top of the payload tube. The piston is slipped in on top of the harness. The main chute and rest of the harness are neatly packaged and slipped in on top of the piston. The nose cone with radio already mounted (and turned on!) is slipped into the payload tube. I secure the nosecone to the payload tube with a 2-56 nylon screw used as a sheer pin and pressed into aligned holes in the nosecone shoulder and payload tube. I cut off the screw flush with the outside of the payload tube. If I need to remove it for some reason, e.g. aborted launch, I just press it in until it falls into the radio compartment. This as well as the ventilation holes are detailed in the kit instructions which you can download from Wildman's site. I aligned my sheer pin hole, the payload vent, the fin can vent, and the Power Perch magnetic switch location so I can easily tell where to slide the magnet to turn the Raven on and off. I put four small AV vents near the bottom of the payload tube, just above the coupler/payload joint and out of phase with the other holes. Be sure to arm the altimeter before leaving the launch stand and heading back to the launch control area.
In flight, when the altimeter detects apogee, it ignites the apogee charge which pressurizes the fin can and separates the rocket at the fin can/payload junction. This de-stabilizes the rocket so it does not come down ballistically. The backup apogee pyro charge goes off shortly after according to the program set in the Raven. The nose cone is prevented from falling off or being jolted off by the sheer pin. The de-stabilized rocket falls to 700 feet at which altitude the Raven ignites the main pyro charge to pressurize the payload tube, break the sheer pin, eject the nosecone and deploy the main. The main backup pyro goes off shortly after according to the program set in the Raven. The Raven allows you to program each of the four output channels independently based on a large number of parameters including user defined altitudes, times, velocities, accelerations, apogee, etc.
If you wanted to use a drogue chute or streamer with this setup, you would stow it in the fin can attached to the harness between the bottom of the AV bay and the fin can. There are other ways to set it up this is just the one I chose.
A few additional thoughts:
- After a couple of flights I noticed that the kevlar harness material was getting fuzzy where it rubs on the edge of the fin can opening. This makes sense to me since the rocket falls several thousand feet from apogee with the fin can and payload whipping around. The main harness which falls a much shorter distance and likely with less whipping did not abrade noticeably. I took a piece of accessory cord, pulled out the core fibers, and slipped it over the harness at these rub locations as an abraision protector. I secured it with a light hand sewn stitch to keep it from sliding out of position.
- When you are setting up your harness lay everything out to make sure the various parts of the rocket can't bang into each other as it comes down.
- I thought my rocket drifted a lot with the drogueless setup. Be sure to sim your setup before flying as you might be surprised how far it could drift especially if you are going for altitude. On the day I flew, I believe someone said the jet stream was right over the field at 15k or so and so I expect on my L2 flight I had some pretty stiff winds aloft that really moved it.
- Whatever you do, don't forget to ground test your setup to make sure all the laundry gets deployed as expected.
