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:

Update 9/9/2023: Yeah, I've let this sit for a while. I have a countdown app on my phone that helpfully tells me that there are 48 days left until Midwest Power, plus I might have an opportunity to do a shakedown flight at my local launch the weekend before. So I need to get going!

Update 9/10/2023: I settled on the Fruity Chutes 48" Iris as a main parachute, and ground tested with it. This is Buster's pilot chute, and is also going to be used as the main for the Kerbal 5, which is about the same weight. I have a new 80" Top Flight Recovery streamer to use as a drogue.

Update 9/18/2023: since that 48" Fruity Chute is now nominally being used for three rockets (Buster, Kerbal 5 and Black Widow) with a possible fourth on the horizon (Peregrine), I decided to order a second one. The old one is red/white, and the new one will be yellow/black. I'll rig the yellow & black one in Kerbal 5 for the fall launches.

Update 10/14/2023: (possibly) one week to launch, if we fly in Elsberry next weekend. If not, two weeks to Midwest Power. Time to finish this up.

TODOs as of 10/14/2023:

Update firmware and set clock in old Mobius camera, and make sure it still works
Update checklist

Project notes:

Entirely new 3D-printed sled
- New BlueRaven altimeter
- 3.7V 380mAH LiPo battery
  - Extend the battery's plug to 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
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
- New drogue streamer
  - 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
- Use 48" Iris Ultra as main parachute
  - Have had multiple occurrences of the primary charge not getting the main out
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