Ad Astra PDR Notes

Avionics

• Don’t say eliminate all points of failure

• Consider how avionics structure integrates with regular structure

• Failsafe feature is irrelevant on Eggtimer Quantum

• Clarify and make sure pro vs con for cost and owned are consistent with flight computers

• Consider combining different flight computers to satisfy requirements

• Know what the safety features are for the Eggtimer Proton

• Don’t say the TX is slightly larger than the mini if it is 2x the size

• Don’t listen to nate about the featherweights

• Consider RS41 Radiosondes

• Low self-discharge rate for batteries doesn’t really matter for this application

• Don’t say low energy density when no sizing has been considered yet

• Consider leads on your batteries

• Consider LiPo rectangular

• No safety for over-discharge?

• Lion discharge rates can vary

• Don’t buy batteries without leads

• Don’t use batteries in a holder because spring connections are prone to brownouts

Payload

• Define immediately searchable area

• Test successful deployment in any orientation

• Consider volume and correct geometry of model rocket

• Consider max height of rocket

• 3D printing tolerance should not be an issue as long as its accounted for

• Consider how you would glue sabot leaves together

• Try and use the Prusa XLs for sabot printing instead of BigRep

• Can combine sabot and spring release design options

• Consider more details concerning priming and constraining the spring

• If using streamer, we know Cd for the material and manufacturing style if copying IREC

• Featherweight is probably too expensive

• Need to test more with FUVISION camera

• Estes cam has 40 minutes of battery life

• Henceforth the mini rocket will be referred to as little bro

Recovery

• Use Sondehub weather calculations

• Avionics integration with tender descender

• Write out descent rates on reefing slides

• If using Kong Streamer, it is safer to assume Rocketman Cd is accurate

• Don’t use elastic line (please)

• Consider how the main chute is constrained at apogee deployment

• Will be a challenge to do that

• Swivel link benefits are hotly debated

• While a single streamer may be the easiest method for recovery, it does not prepare you as well for IREC

Structures

• Apogee goal is a team-set requirement, not in the design requirements document

• Check max URRG height

• Plywood bulkhead image contains 3D geometry that is not able to be laser cut

• Possibly consider G10 fiberglass bulkheads but also know that this would be more expensive

• URRG won’t get hot enough to warp PLA

• External layup on 3D print nosecone could be an option

• Could layup FG over plywood as a fin option

• Fin drag vs number of fins analysis is also heavily dependent on area and geometry of fins

• Make apogee requirements consistent

• Openrocket needs some work, this can be gone over in depth at a later meeting

• Estimate to calculate TWR

• You can buy metal

• Metal is cheap