Level 3 Project
Electronics/Recovery
Electronics
Electronics first, the altimeter bay is comprised of one 14" coupler, one 3" piece of body tube, 3 sections of 5/16" all thread, two 5/16" u-bolts, two missile works switches, two end caps, and assorted hardware.
The majority of the components during build. Each end cap is comprised of two 1/2" bulkheads, one coupler and one airframe for a total thickness of 1".
Inside the altimeter bay I placed another bulkhead 7" down from the top of the altbay. This was to decrease the volume of the bay where the altimeters are housed to make port holes more reasonable in size. This bulkhead was coated in epoxy and permanately set.
Sleds were made for each altimeter out of 1/8" ply coated on each side with one layer of 6oz glass, then a tube was applied to slide down over the all thread. The tube used is just the tube that AT uses to place their igniters in, in the reload packages, these tubes make great 1/4" launch lugs also.
Exterior of the completed bay after paint. They're hard to see being black on black, but if you look closely you can see the missile works switches on the airframe tube.
Also note the threaded inserts in the end caps, used to secure airframe sections to the alt bay.
End cap after ground testing, looks a little different now, in the future I'll make a note to coat the end caps in a light layer of epoxy, as it cleans up well where as the exposed wood doesn't, the blackpowder stains it pretty good. You can see the terminal blocks used, ejection wells, fender washers and nuts used to complete the end cap assemblies.
Inside of the alt bay with the two missile works altimeters installed. The sleds for these are cut to to the specific length to just allow them to fit inside, when the end cap is installed it closes up tight to the top of the sled which helps to hold it in place and doesn't allow any vertical movement of the altimeters.
The alt bay and the two altimeters on their sleds.
The plan for electronics is to have one charge for the apogee deployment. Each altimeter will run one match into the apogee charge. The charge has been extensively ground tested and will be just a bit heavier during flight to insure separation.
For the main event Altimeter 1 will be set to deploy the main at 1,000 feet with 4.5 grams of 4F blackpowder as the charge. Altimeter two will be set to deploy at 800' with 5.5 to 6 grams of 4G blackpowder as the charge. Extensive ground testing has shown 4.5 grams to work just fine, but just in case there is a second more substantial back up charge.
Recovery
This will be a dual recovery flight, going either drogueless or with a streamer at apogee and then with a Rocketman R16C EXP for a main.
The main chute will be loaded into the above deployment bag, a free bag style bag. For this particular body tube and parachute the chute will be "S" folded into the bags and the parachute shroud lines will also be loaded into the bag.
The nosecone will have a kevlar tether on it to which an R4 pilot chute will be attached and the other end will be attached to the deployment bag. After the main charge fires the cone and pilot will be ejected, and if like the ground tests possibly the deployment bag also. The pilot chute will catch air and then drag the bag off of the main chute which is attached to the main recovery harness which goes on to connect to the rocket. The cone, and deployment bag will come down on the pilot chute separately.
This being my Level 3 attempt I didn't skimp on the recovery, this is a Rocketman R16C EXP, their pro experimental chute, very nicely done in custom colors for me, and very nice workmanship. 1.9 oz ripstop balloon fabric and heavy tubular nylon shroud lines over the top, I've used rocketman chutes in the past and like them, and really like this chute.