Overall Notes

Structures

• Requirements

  • Distinguish between should and shall with DTEG reqs

  • Consistency in dimensions (diameter, radius)

  • Use testing over analysis for FoS

• OpenRocket

  • 10 mph wind case

  • Loki Research motor

  • Both satisfy rod speed req using base mass

• Motor Selection

  • TWR calculated with ~28 kg mass

  • CTI issues (can be elaborated on later)

  • Is the Loki motor in stock? (need to check on that)

  • Need to do a more in-depth price comparison for jumping to N-class

  • Have we considered the M6000? (large overshoot)

  • Motor unreliability as we jump classes? (likely a non-issue, consult tech reports to confirm)

  • Loki motor burns blue, pretty cool

  • Prioritize off-rod velocity

  • Test parts to higher stresses if concerned with a more powerful motor

• Nose Cone

  • Is the strength difference between CF and FG a valid concern?

  • What is the basis for saying CF is easier to remove from a mold than FG?

  • Are we considering different shapes at this stage?

    • Not considering other than a tangent ogive

    • Possibly look at Von Karman

  • Don’t worry about a tip for Mach reasons if under Mach 1

• Body Tubes

  • Layup has less surface finish work than winding (except for seam line)

  • Layup strength comparison is dependent on the direction of fibers in purchased cloth

  • For winding where would we apply graphite powder?

  • Consider using the paint booth for heated cure cycle (look at temperatures needed and temperatures that can be achieved)

  • Winding pattern (current 60/30) though to change because of manufacturing process

  • Find out weight difference between layup and winding

  • Consider mechanical improvements to the X-Winder (in progress already)

  • FG frays far more during winding

  • Consider sourcing better FG tow

  • Prepreg FG tow?

  • How does cost per weight translate to cost per length unit of tube?

• Bulkheads

  • Spar thicknesses vary a lot

  • Uniform spar thicknesses for testing and adding fillets to the thin membrane

  • Decrease overall bulkhead thickness (.5” to .375” or .25”)

  • Consider mounting space when looking at spar design

  • Why does the four-spar bulkhead maintain equivalent strength as a solid bulkhead with less mass?

    • Section moment considerations

• Rail Buttons

  • SRAD

    • Why not machine plastic rail guides?

    • Aluminum rail button testing on L1s?

    • Plastic is actually easier to machine

    • Are these rail buttons better than COTS?

    • Not many teams use SRAD

    • Combo Al/Delrin rail buttons

  • COTS

• Boat Tail

  • 3D Printing

    • Consider heat deflection temperature, not melting temperature

    • Glass Transition temp for PETG is around 80 degrees Celcius (per Deeb)

    • Consider simply using PETG again if using same or lower-thrust motor

      • Careful is going to Loki or higher

    • Consider layer height for printing

    • Worth testing layer height strength properties

  • Composite Layup

    • Is the compressive strength worth it here if using a fibrous material?

• Fins

  • Numerical optimization for fins

  • Concern about lack of fin tabs if using tip-to-tip layup

• Thrust Plate and Motor Retainer

  • The screw size restriction was due to the size of retainer

  • Think about screw on and one “locking” screw through both pieces

  • Slide 45: NO

• Blockers

Avionics

• Requirements

  • Minimize in-field assembly time by doing more before arriving at the VLA

• Wiring Diagram

  • Add switches to GPS

  • Careful about where wires plug into

• Backplane

• Connectors

  • Move placement of connectors

  • Consider alternatives for bulkhead wire pass-throughs

• Flight Computers

  • Why only RRC?

    • Because

• Trackers

  • Featherweight ground station data can be sent to our ground station

  • Featherweight is more reliable

  • Cost of featherweight is comparable

  • Working ground station is good

  • Big Red Bee size is far larger

  • HORUS will not get drowned out

• Live Video Transmission

  • HDMI connections can be somewhat unstable

    • Perhaps mitigate by using a small 3D print bracket

  • Drone cameras will likely be rated for higher G loads than the rocket will experience

  • Range ratings are likely unreliable and should be tested

  • RF transparent materials can still affect the signals

  • Live video challenge requires 1080p 30 FPS

  • Bad video is still worth something

  • Interference concerns with transmitting on crowded bands

    • Video transmitters can shift frequencies

    • Need to see if MCC approves that

  • Need to consider the drain timeline

  • Consider sending a turn-on signal to start the live video

    • It could also use boost detection

  • Really need to deep dive into how we can safely remotely turn it on without missing boost

• Heat Management

  • EMI generation is likely a non-issue

  • Thermally conductive plastics

  • Turning on the runcams close to flight could negate the need for an airflow solution

  • External heat sink can cause more damage upon recovery

  • Test a large amount for fan system

  • Figure out activation issue before heat management to understand how much heat management is truly needed

  • EMI could also throw off magnetometers on non-flight critical components

• Battery Chemistry

  • No individual lithium-ion cells

  • Look at batteries with leads rather than contacts

• Engineering Cameras

  • LED is to help ease the exposure shock from brightness in NM

  • Come up with the number and location of modules

  • What view are we looking at for live video?

  • Need to have a large camera discussion with multiple subteams

Avionics Bay

• Removeable Bulkhead

  • Inset Edge Circle contains the load and makes the connection weaker

  • Clover should not have a manufacturability issue

  • Add in a flat on the clover for keying

  • Clover design can only be epoxied on one side for fillets and the application must be careful to not impact the keying geometry

  • Consider how deep in the tube the clover is

  • Consider what tools can fit in to actually screw in the key

• Material Selection for Skeleton

  • Waterjet isn’t as much of an issue this year

  • Check Metals Depot for Aluminum

• Component Mounting

  • Label things

  • Removable top if implementing fixed sleds

• General Improvements

Recovery

• Requirements

  • Take care to follow the main altitude deployment DTEG

  • Give time for the main to inflate to meet the speed req

  • Consider how payload’s recovery system deploys

• Streamer

  • Mitigate the length of the harness to reduce tangle risk

    • Dual Bay helps with this

  • Understand why we use a streamer instead of a chute for drogue

  • Consider Pilot Chutes

• Main Chute

  • Find out and compare chutes based on descent rates

  • Decide on the correct size for the mass of our rocket (likely larger this year)

  • Vented chutes open far slower than non-vented

  • Put more thought into other factors surrounding descent rate decision

  • Consider Pilot Chutes

• Links

  • May need to buy more quick links

  • Visual indicators for quick link tightness

• Shock Cord

  • Maybe look into lower-rated shock cord

    • ESRA might want us to use 5000 lb for some reason

  • Ratchet Straps?

  • Cord Length needs to be figured out

  • Watch for corrosive BP protection

  • Consider how to secure the line protector

    • Sewing

  • Compare cut resistance of shock protector

  • Could attach COTS protection with heat shrink on either end

  • Reference OMEN Tech Report for Separation Shock Calculator

• Foxhunt

  • Figure out where to place foxhunt beacons in the rocket

  • Look into other foxhunt beacon options

  • RS41 can possibly act as foxhunt beacon in AV bay

• Test

  • HAB streamer tests?

• Blockers

  • Consider Wildman Rocketry as a recovery component supplier

Payload

• Requirements

  • Make sure payload can transmit without extended member

  • Recovery has not imposed any interface requirements

  • Sabot keying requirement

• Extendable Antenna

  • Dust considerations hindering mechanical systems

  • Sheet metal manufacturing should be somewhat simple

  • Fishing line as an extendable string

  • Consider using the extension as a 2m antenna

• Self-Righting Mechanism

  • Figure out what to do if it lands on the top or bottom

  • Round bottom and modify sabot

  • Is it worth the cost of a COTS emergency HAM inflatable antenna?

    • Too large of a package for the member

• Frame Ideas

  • The Back Plate has more strength concerns due to larger moments

  • Stilt City - thanks yev

  • Offset parachute introduces more concentrated stresses and increases the possibility of shearing shroud lines due to contact with edges of the payload

• Parachute Antenna

  • Mini Chutes

  • Crazy antennas are mitigated simply by another tracker

  • Extra parachute is a massive tangle risk

• Battery Options

  • Use packages with leads not individual cells

  • Flat pack battery options

• Cameras

  • Second lens on cam #2 has both analog and digital lenses

  • Also considering the same higher-end runcams as Avionics

• Sabot

  • Change where the shock cord pass through is located

    • Does not fit into tube tightly as is

  • If implementing the band idea run it through both sides

• SRAD PCB

  • Scope creep concerns

  • Most of this can be reused in terms of board design from previous boards

  • Figure out if the PCB provides power to servos as well as control

• GPS Tracking

Finished