A Tripoli Technical Advisory Panel Document

By Alan D. Davis TRA L3 #5935

Objectives

I realize this may not be a requirement for my L3 project but I believe it is an extremely integral part of any complex project. I am also a PADI certified ocean dive and there is a saying that I am sure some of you will recognize if you are a diver also, it's called "plan your dive and dive your plan". Basically translated to HPR if you plan your rocket and follow your plans then your project will have a much higher chance of success and longevity. I know the amount of coin and time spent on these complex projects can be enormous and with a little planning and fore thought then these items will not end up being excavated via shovel from your favorite launch site.

Okay enough philosophy, just a few highlights of what I plan to have my rocket accomplish.

  • 1st: Perform as designed and built. If I follow my plans and objectives then this should be a given.

  • 2nd: Be Cost effective. I guess this depends on several factors, income, budget etc. but we as responsible consumers should only do things within our budgets, I have a nice house but I am not Bill Gates and my rocket is not the next generation of Space Shuttles. Of course it is hard to put the word responsible in this objective, luckily I have no wife to justify why I need dual altimeters as opposed to replacing that old vacuum cleaner.

  • 3rd: Don't re-invent the wheel. There is a lot of great and proven products out there to achieve L3. This is not the time to test and try new and unproven products.

  • 4th: Live long and prosper. Proper planning and construction should result in my rocket attending many launches and burning some substantial AP.

Post-Flight Objectives Analysis

Since I posted this page to have some objectives during the design and construction phases of the project I wanted to do a post-analysis of those objectives after the successful Level 3 flight.

  • 1st: Perform as designed and built. The Phasar L3 performed almost exactly as I intended it to based upon all my RockSim calcualtions and design. I knew the rocket was overstable with a static margin of stability of 9.5, which is not bad, but anticipated a slight pendulum motion off the pad until the M1315W gained enough velocity. After review of the flight video this is exactly what happened, a very slight back and forth motion in the booster section for about 1 second of the flight. Also anticipated a slight weather cock depending on the wind speeds at launch time since the fin area was quite large for a 4" diameter rocket. The winds during the launch were about 7mph and the rocket was launched perfectly perpendicular to allow for a slight weather kick. Again the flight video revealed the rocket did a slight kick right into the prevailing winds that day. These 2 items were anticipated and the Phasar L3 performed exactly as Rocksim would have predicted.

  • 2nd: Be Cost effective. In my opinion I believe the total and final cost of construction and flight ofthe Phasar L3 was quite reasonible for a project of this magnitude.

  • 3rd: Don't re-invent the wheel. There was no products and/or procedures that I used in the development of the Phasar L3 project that had not be used in any of my previous rocket endeavours with the exception of using shear pins for the 1st time. The shear pins were used only after sufficient ground testing and consulation with my TAP members.

  • 4th: Live long and prosper. The Phasar L3 survived an extreme L3 attempt without any damage and there is no reason additional 75mm motors will not be used in this launch vehicle.

  • In Conclusion: I developed the Phasar L3 program around these ideas and proven techniques and followed my objectives as close as possible and believe because of this the project was a complete success on it's 1st attempt.