P08106: Flying Rocket Body & Rocket Stage Integration

Interview 3

METEOR 3rd Interview Notes
Date: 4-17-07
Interviewers: Lee Rynearson
Interviewees: Dorin Patru (DP)

NOTE: Unlike the previous interview, hand notes were taken because voice recording was not available. Thus, this information does not constitute a transcript.

Suggested reading: Orbital Mechanics by Howard Curtis, last chapter has staging info

Who made the original horizontal test stand?

Project P06006 made it and it was improved by the vertical test stand team P07110.

Given that at least one team is integrating the steel and flying rockets, does the stand need to be compatible with flight fuselages, or steel rockets, or both?

The third stage will integrate steel and flying, stages 1 and 2 will be working on both as communication issues between teams (steel and flying) in the past have been a problem. However, the horizontal stand tests rocket motors only.

Which stages does the test stand service?

Stages 1-3. Also, the current test stand team will be responsible for keeping the other two test stands working and possibly upgrading them if required.

When is the next test?

Sunday at 8AM.

What safety systems need to be integrated into the test stand?

Right now we have two valves on the NOX, one manual that the last person leaving the blockhouse opens, and one electric one. The test stand team will collaborate with the stage teams to document required safety procedures, but these should be easily adapted from existing documentation shouldn't be much work. Check the procedures team (p07107) for an idea of what this entails. We will create similar procedures from the template.

Will separation be a factor in any of the stages?

Stage 3 may look at separation, stages 1 and 2 will not. It has no bearing on the test stand though.

Are there any considerations for future proofing that you can think of?

Just make it big enough for the new stages.

Have vibrational problems come up in the past / would vibration be a likely problem in the test stand?

Thrust is largely static and in one direction, we haven't observed vibration in the past, the FOS in rail design is huge, everything bolted down, weight so high, that the forces and any vibrations verge on insignificant.

What is the official name of the project?

The official name is Rocket Engine Test Stands.

What are the ideal and marginal Factors of Safety?

FOS of ten is minimal, 20+ would be ideal. Current FOS in some areas exceeds 300. Weight of the steel testing cylinders is so high that they wouldn't fly / fly much even if they weren't secured. The relief valves would blow and the nozzle would break before it would fly off the rack. (thought that FOS of 5 / 10 might be enough)

What is the maximum weight the stand must support?

The real values will be only determined by the stage SD1 teams, but definitely should be less than 100kg for the motor itself of stage 1.

(***outside note - including fuel and nox tanks? Or are those mounted separately?)

What is the maximum thrust the stand must support?

We can anticipate in the neighborhood of 500lb thrust for stage 1. SD1 will give better estimates.

What is the maximum length of rocket the stand might have to support?

Ideal oxidizer to fuel ratio from books is 6 or 8 to 1. We've found 4 to 1 is best but with uncertainty in measurements could be anywhere from 3-6 to 1. Only get about 20% precision between tests for how much fuel is used.
The METEOR project will emphasize shorter, fatter rockets because we're firing them outside of the atmosphere where aerodynamics are very minimal - makes control easier. Also puts us closer to published results with fuel / oxidizer ratio and thrust. Shorter chamber has proportionally more thrust.
The longest rocket stage should be less than 6ft. Second stage not more then 4ft. More dimensions TBD in SD1.

What diameters might these stages have?

DP thinks the 2nd stage should be around 10-11 inches in diameter and first stage somewhat larger, probably less than 2ft. TBD in SD1.
What accuracy is desired in the data from the test stand?

We can reuse some of the equipment from last year, but the goal is to strike a balance for accuracy. We use commercial equipment and it shouldn't be that hard to get quite close to the true values without getting into really advanced stuff. 1% error is fine. Industrial standard sensors should be fine.

When are the SD2 teams likely to need to use this equipment / when should it be completed?

Stages 1 and 2 will need to test between weeks 6 and 8 of senior design 2. If the test stand is totally ready by the end of week seven then DP is happy. It remains to be seen if that makes teams happy. Targeting end of week 6 gives slip room.
Usually the biggest challenge for METEOR teams is getting special materials and items in, probably not such a big problem for test stand.

What legal or regulatory issues might need to addressed during this project?

We run all our stuff through the Risk Management office, we have to draft a report and give it to them, they tell us if / who we need to talk to. This is a responsibility of the team, working in conjunction with the stages, DP, and Kozak, but adapting stuff from before will again be easy and acceptable.

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