Nice to see so many people following the flight! It was certainly an ambitious project, but I think overall it went pretty well. Would have loved to see the second stage ignite but still a great flight in my book. Looking forward to making another attempt next year, construction should be easier after all I've learned in making this rocket. Going to be a ton of work again for myself, but at least I will have less classes to deal with doing it as my thesis!
Just glad we got to this point - halfway through the year it didn't even seem like the school was going to let me/us... As our contact at Spaceport America said, Princeton was by an order of magnitude the most overly risk averse/slow school they had ever had to deal with (took 3+ months to get our contract with SA approved by the schools risk management team/office of general counsel despite the engineering dept./faculty approving it from the get go)
It is standard practice to have the recovery electronics bring back the second stage if it doesn't light. No extra design work is needed. The only consideration is that the descent rate will be higher due to the mass of the unfired propellant.
Not exactly. The use of commercial motors limits the options for the flight profile, thrust curve, mass distribution, mass ratio, and second stage ignition characteristics, to name a few. Though, it is certainly faster to get to a flight-ready rocket, but not optimal. This is also contrary to your previous statements that it must be done without an airframe, with a fin can attached to the motor.
I think it was an excellent first attempt for a student team in a short time. The technical document is very good, but needed some additional review that probably wasn't possible in the time frame they had.
Thank you! Yeah I kind of wish I had had more time to put into that report, it kinda got left to the last minute (i.e. two days) between Formula Hybrid competition stuff and shipping out the finalized rocket - definitely left some stuff out unfortunately. Could have easily written double what it was!
Any major design comments? Don't get much feedback/help from the faculty here, only thing they do is fluids/combustion research haha! I would say major things that needed a bit more work were ignition methods and more analysis of the effect of wind on dynamics (some of which was done but not included in the report as my cohort did some of that work so couldn't put it in my personal report). Also left out quite a bit of more broad FEA on things like overall vehicle stack, thermal expansion at joints, vacuum testing of igniters/deployment/batteries, etc.
Our final ignition method used a slow burning igniter and a burst disk on the nozzle to maintain ~ ground level pressure and help the motor come up to pressure faster (recommended by Karl @ AT). Initial analysis of accelerometer looks like both worked as intended, but the disk needed to be sized for more pressure - it ignited and produced momentary thrust then immediately chuffed out.
The instability off the rail seems to be due to an unexpected wind shear/gust off the pad in combo with such a long slender vehicle. We plugged in a 20 mph ground wind into ASTOS and got nearly the exact oscillation shown by the rocket. Combo of slightly larger fins, longer launcher, spinning up booster, and possibly a shroud for sustainer fins are under consideration for solving this for next year.
Spaceport America is the only place you could try something like this......and very few teams can scrape up the launch fee......
It isn't particularly bad for what you get - ~$5,000 gets you access to WSMR's airspace and things like a place to work with power/AC/fire crews/etc. They're certainly not making money! I would bet most of the 120+ college teams going to the SpacePort Cup pay nearly as much to fly/house/feed their teams - it really is in reach of most teams. On par with cost to go to an FSAE/Formula Hybrid competition as well. Compare it to WSMR which would be $50-100,000 or Wallops which was $100,000's, or BlackRock which is free but smaller and a logistical nightmare especially for an east coast school.