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Maybe try and get in contact with SPL to do a piston test in the vacuum chamber sometime in the next two weeks?
Or figure out a way to use the mini vacuum chamber in lab
Piston
Used on Phoenix, Staging Demo and HADES
Piston failure experienced on Staging Demo II (resulted in sustainer destruction)
Pressure sealed so can be used at high-altitudes
Although risk of no pressure seal on the firebolts (mitigated using hydrostatic testing)
Overall black powder is less reliable at higher altitudes (lower pressure slows down combustion propagation)
Test hot glue instead of epoxy as a sealing method for the firebolts
Takes up 8 inches in length of mpt
Can be reused
Look into & test shorter pistons?
Piston chosen:
Variety of piston lengths: https://www.mcmaster.com/products/pistons/double-acting-round-body-air-cylinders/More info on different types of pistons: https://www.globalspec.com/learnmore/fluid_power_components/pneumatic_equipment_components/air_cylinders
BP calculator: https://rocketrycalculator.com/rocketry-calculator/bp-estimator/
Initial Testing for Piston at low pressure
Layout
Shear Pins
Phoenix had 3 on sustainer nose cone and 4 on booster
Medusa needs more shear pins on secondary deployment to ensure there is no early deployment
Swivels
Options:
1500lb ASP Rocketry https://www.asp-rocketry.com/ecommerce/Barrel-Swivel-1-500-Lb-Test.cfm?item_id=159&parent=51&navPanel=
6000 lb from fruity chutes. Supports rockets up to 400lbs https://shop.fruitychutes.com/collections/recovery-and-launch-hardware/products/6000-lb-stainless-steel-swivel
Weight
Sustainer: 15.8 dry, 35 wet. Total: 50.8lbs
Booster: 103lb dry,
Reasons for not using dual stage dual deploy
The proportions of Medusa were not aligned with using a dual stage dual deploy system as well as the risk of coning during launch
Firebolts
- The method used for Phoenix for integrating the black powder charges with the firebolts into the pistons worked but was frustrating
- The teflon tape used to contain the black powder was liable to tear when screwed into the fittings at the bottom of the piston
- Firebolts wiki page
CO2 Canisters
Researched, but decided to stay with piston system
Good for use at high-altitudes (20k ft+) b/c completely pressure sealed
Takes up approximately 5 inches in length of mpt
USCRPL Recovery
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Presentation https://docs.google.com/document/d/1-FvnbYQmETId8Ko6nY0LdCxwcloM4aGdy2pHURnmPTc/edit
https://ideaexchange.uakron.edu/cgi/viewcontent.cgi?article=3029&context=honors_research_projects
This is an article someone wrote about how they designed/built/tested a CO2 deployment mechanism using a solenoid
CO2 has lower pressure impulse than black powder
Discusses difficulties with sealing
Also gives approximate calculations for how to find co2 canister size
fruity chutes info: https://fruitychutes.com/files/blog/Rocketry%20Recovery%20Technology.ppt
COTS CO2 Canisters:
https://www.apogeerockets.com/downloads/PDFs/CD3_Manual2009.pdf
https://www.tinderrocketry.com/rocketry-co2-ejection-system (instruction manual gives bp to co2 conversion)
RAPTOR Tinder Rocketry
$145
Tested in -25 F and Vacuum tested simulating 100000’
Need a mechanism to poke hole into CO2 canister
Spring-loaded system
Spring forces may be unpredictable at higher altitudes
Vulnerable to vibrations during launch
Needed to by loaded during launch, so risk of early deployment
Solenoid
Arm attached to solenoid that moves to poke hole
once Pyrotechnic system
Still contains issues with black powder
Look into finding better way to seal
Reliable on ground, but questionable at high altitude
Servo
Valves
Powered by outside source that would open valve instead of poking a hole
Avionics potentially in nose cone depending on direction of gas canister
Need to figure out if one way is more effective for parachute deployment
Issues to test for:
Leaking of CO2
Premature puncturing
Failure to puncture
Tests should take into account low temperatures at higher altitudes, forces/vibrations during flight, etc.
Weight Imbalances from co2 canisters and co2 release mechanism
COTS CO2 Canisters:
https://www.apogeerockets.com/downloads/PDFs/CD3_Manual2009.pdf
https://www.tinderrocketry.com/rocketry-co2-ejection-system (instruction manual gives bp to co2 conversion)
Preliminary Design
CO2 canister sizing
Chute packing volumes
main chutes
sustainer main: 4.3 oz 48 inches, 26 in^3 packing volume
booster main: 16.3 oz 96 inches, 90.5 in^3 packing volume
drogue chutes (estimates)
sustainer drogue: 1.7 oz 18 in diameter, 9.67 in^3 packing volume
booster drogue: 4.5 oz 36 in diameter, 21.2 in^3 packing volume
Multiply the black powder charge size (grams) by 5.0 to determine the amount of CO2 (also in grams) required to achieve the same compartment pressure.
If using this method we need to remember the compartment for Phoenix (that we used 0.2g for) is the inside of the piston, not the recovery compartment
Canister Size
- 12g CO2 Canisters
Layout
Shear Pins
Phoenix had 3 on sustainer nose cone and 4 on booster
Medusa needs more shear pins on secondary deployment to ensure there is no early deployment
Swivels
Options:
1500lb ASP Rocketry https://www.asp-rocketry.com/ecommerce/Barrel-Swivel-1-500-Lb-Test.cfm?item_id=159&parent=51&navPanel=
6000 lb from fruity chutes. Supports rockets up to 400lbs https://shop.fruitychutes.com/collections/recovery-and-launch-hardware/products/6000-lb-stainless-steel-swivel
CO2 System
Solenoids
Weight
Sustainer: 15.8 dry, 35 wet. Total: 50.8lbs
Booster: 103lb dry,
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- Canisters
Other Research
Misc Links
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