Rocket Team Meeting
November 4, 2013
Level 1 Certification
- We got 13 people Level 1 certified à everything went really smoothly…except for retrieval
- In the future, should put trackers or radio beacons for easier retrieval
- Should put full name, phone, and MIT on outside of rocket
- Short pre-launch check-list – the parachute, did you set delay charge, etc. – before launch
- If people want to try for Level 2, need bigger engine and take a test
- Need to get under altitude limit of 3,000 ft in Amesbury (weigh rocket down, drag streamers, etc)
- Might want to try for another launch site with higher altitude (Maine w/ 10,000 ft?)
- Should fiberglass upper section of rocket and definitely need to put radio beacon; possibly need to use dual-deployment parachute system à altimeter and avionics bay
- Next launch is November 16!!
Sensors & Instrumentation
- Strain gauges & pressure transducers
- Letendre has pressure transducers that will work; borrow amplifiers and strain gauges from Perridichi
- Stop test stand from moving à sandbags for weights (portable weights à easy setup)
- Test stand main structure idea = uni-strut
- Con for wood – wood + fire = EHS very, very nervous
- Need several strain gauges rosettes around the pedestal so we can measure whether the thrust is not aligned with the axis
- For spike and liner for cold flow as mock-up, want to use some sort of plastic instead of ceramic à options?
- Nylon = cheapest and easiest to machine; also softest (might compress at lip; if aerospike stretches and closes the gap à really bad!!)
- Polycarb = harder but more expensive
- Delrin = already on hand; still a good option
- PET = harder than nylon but still pretty cheap
- Pipe sizes for cold flow? 3/8”
- Eric has software and MATLAB code for modeling losses in pipe, etc
- Need solenoid valve to turn engine on without being in room à anything we can use in Talaris?
- Schlieren photography – how large of a mirror? 6” spherical mirror for $70. Any bigger and want to use parabolic
- Trade-off between spherical and parabolic = parabolic has some distortions but cheaper
- Want to image 6” section at tip of engine
- Already have camera; might need plexiglass for case for camera
- Need to pick mirror and order by Weds?
Engine Geometry & Design
- Material to make the engine? Trade-off = aluminum vs. steel
- Big factor is ductility in metal, especially for a pressure vessel (if it fails)
- Steel more brittle than Al and therefore using Al might be safer?
- Steel Acetenic 300 Series (316 or 304 stainless steel alloy) à ductility similar to that of Al and maintains its tensile strength
- Both Al and steel will support vessel during firing but Al might deform under own weight and fail after firing
- Steel = more expensive and harder to machine but machining difficulties of steel worth not replacing our pressure vessel after every single firing
- Ceramic materials to make liner
- Two types fairly cheap and come in castable powder
- Make a mold for part and cast it (for hot fire)
- While mold cures, we want to keep it under light vacuum to suck up all the air bubbles when we can
- Borrow Unified vacuum chamber for this
- Make injector out of a stack of 3 plates
- Top plate with arrangement of 4 holes (pressure sensor, spark plug, oxidizer, fuel)
- Middle plate w/ 2 channels (1 loops from fuel port to distribute fuel; other loops from oxidizer port to distribute oxidizer)
- Bottom plate w/ ring of holes for fuel and concentric ring of holes for oxidizer
- Holes angled so fuel and oxidizer mix à stream of fuel & oxidizer mist finely mixed
- Talk to Edgerton – do they have a 5-axis mill?
- Surface Solutions – contact him for machining complex parts; do not use Central Machining
Master Equipment List
- Management tool to keep track of all components you have for each subgroup of project
- Name, description, cost and useful properties (time to arrive, mass, who last ordered, etc)
- 1st stop at auditing budget & checking mass!