Black Widow (altimeter bay redesign)

Black Widow has not flown since November 2016. It’s a good rocket but has some usability and recovery problems. The goal of this project is to refit it with new electronics and solve as many known problems as possible, making this back into a workhorse high-performance rocket. I have five flights’ worth of data and video to review and see where improvements can be made. This page is just a copy of my own project notes.

Update 4/23/2023: I found out that the battery I was planning to use (2S, 1200mAH, 30C) was not going to be suitable, because in a short circuit it could produce more current than the BlueRaven's pyro outputs could handle (36A vs. 22A). I found another battery (1S, 380mAH, 25C) that should be suitable, maxing out at 9.5A. I should have the batteries tomorrow and the proper wiring connectors on Tuesday, and will need to alter the sled design and reprint it.

Update 4/30/2023: Successful bench test of new altimeter and wiring:

TODOs as of 4/23/2023:

Select and order 2-conductor locking plugs for battery connection [DONE, ordered 2- and 3-pin JST SM connectors from Adafruit]
Modify sled design for correct BlueRaven footprint [DONE]
Modify sled design for new battery [DONE]
Print new sled [DONE]
Assemble & wire new sled [DONE]
Test BlueRaven app [DONE]
Bench test [DONE - first bench test did not fire channel 3, but this turned out to be a bad e-match; second test confirmed the bad match and then fired all four channels]
Select new parachutes
Check rivet holes and re-drill if needed
Ground test
Design new nose sled for TeleGPS [DONE]
Print nose sled [DONE]
Test old Mobius camera and make sure it still works OK
Clean everything
Touch up paint (maybe)
Buff / polish
Paint alignment keys where needed
Design and print new "ground station" bits (see below)

Project notes:

Entirely new 3D-printed sled [designed, first iteration printed]
- New BlueRaven altimeter
- 7.4V LiPo battery
  - Keep its charging plug accessible
  - Replace the battery's plug with a locking JST connector that can be accessed from the removable end of the coupler, so the pin can be put in the pin switch before connecting the battery]
- Pull-pin switch instead of magnetic switch
- Wiring should be hidden or managed by the sled as much as possible [for now I think I'm just keeping wiring neat with zip ties]
TeleGPS
- Design and print a new sled
- Could it use a pull-pin switch also?
Camera
- Is it possible to remove the old shroud and replace it with a new one for the new camera? [In short, no; if we need to switch to the new camera, we'd have to replace the entire upper airframe tube.]
- Otherwise, is it possible to add the new camera horizontally in the center bay? [No.]
Recovery
- Possibly replace drogue chute
  - Re-watch old videos and see if there’s a solution to drogue problems (spinning, falling nose-down)
  - Have multiple notes about the Spheracutes drogue pulling the upper and lower airframes together after apogee, and either colliding or nearly colliding
- Possibly replace main chute
  - Have had multiple occurrences of the primary charge not getting the main out
  - Maybe a deployment bag?
Physical assembly
- Make sure everything has clear alignment keys (stripes on outside)
- Check coupler fitting on cold & hot days
- Check fit & usability of plastic rivets
Telemetry
- Determine whether I can run the BlueRaven and Altus Metrum apps together
- Add a phone holder to the Yagi antenna
- Add “feet” to the ends of two reflectors on one side of the Yagi so it can be set down on the ground or on a tabletop (with the reflectors vertical and the camera and phone right way up)
Sim & test fit DMS L1000 (currently sims about 10k/750mph)
Update the checklist