The Manhattan Project PDR Notes
- Donovan Barros (RIT Student)
Analytics
Structures
The motor should have a fast burning motor (low burn time)
Look into shorter burn motors
Make sure stability is calculated by graphing for off-the-rod stability in different wind conditions (follow the design document)
Try to minimize empty space
Figure out how the avionics bay is secured
Don’t lock yourself into a fin design, they can be done at the end
Fin Flutter calculations are incorrect
Missing bulkheads
Missing thrust plate
Missing nosecone
Missing motor retainer
Missing access points
Consider access points
Payload
Add in payload mission requirements
PETG is not 1.5 cents per gram anywhere for good quality
All designs would need CAD
Carbon Fiber would restrict antenna design and location
Look into more material options for capsule (Delrin, reinforced cardboard)
Specifically, call out complexity and/or failure points in new designs instead of simply listing new designs as a con
Rails could catch recovery hardware
A tight spring could be an energetic
Use a solenoid or something similar instead of a servo
Characterize the drag on the propellers
Weight concerns for such a small recovery system
Look at NASA paper Alan found to calculate rotor diameter
Consider different drags for spinning the whole payload vs just spinning the payload
Consider frictional effects when not spinning the whole payload
Re-evaluate design criteria so each doesn’t have the same pros and cons
Be careful about balancing the payload mass
Consider using a thrust bearing instead of a ball bearing
Do more research into different types of hinges
Consider SRAD pin and hinge options
If 3D printing rotors, add in external reinforcement on top of print
3D printing rotors may also be challenging due to post-processing
Look into resin printing for the rotors
Why four rotor blades?
Start prototyping rotor blades now
Look into Alan’s other NASA paper on whirlygig designs
Look into different whirlygig manufacturing options
New Barbie option: Lexi’s
No Ebay
Safety concerns picking up barbies
Use separate batteries for tracker and radio beacon
Make sure cell service is available for watch tracking
Test durability of watch tracking
Test watch in L1
Make sure watch can survive impact
LOTS OF TESTING FOR WATCH
Foxhunt practice
Beacon is unreliable on the unlicensed band
Get HAM licenses
Look into the IREC foxhunting beacons
Make something then give structures that mass, don’t worry about conforming to structures before the design is finished
Minimize angular moment of inertia
Flexible barbies
Willing to cut barbie in half
Avionics
Great job on the requirements slides
Higher-res graphics
Passed the screw switch quiz
Name charge lines/signals primary and secondary
Look over quarks or other flight computers carefully if not assembling yourself
Could use different flight computers if need be
Delpoy main failsafe is better than ballistic
Look into RRC2L (we have 4)
Heat shrink GPS onto the eggtimer TX
Consider radiosondes as a tracking option
Radiosondes are big
Make sure batteries can give enough current for charges
Look at more batteries
Expand search outside of apogee components
Look at other battery chemistry besides LiPo (Lion or others)
Recovery
Jolly Logic is a good option for this application, proven success in HPR
Making jolly logic dual redundant is a challenge
Strength test to make sure the logic can survive opening snatch
RIT Launch has minimal experience with dual-bay rockets
Have experience with the success of tender descender single-bay rockets
Careful about load paths
Dual bay requires double the amount of charges
Consider how much wiring is needed to run to the charges
Single Bay vs Dual Bay decision is the most important blocker for the team as a whole
Use base values to start design, don’t push it all off
Use previous PDR and CDR for SR to generate starting values