MHM Day Four - Northern Colorado Rocketry

This topic has 18 replies, 8 voices, and was last updated 14 years, 10 months ago by Chris LaPanse.

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2011-05-31 at 5:53 pm #54438
Chris LaPanse
Did you get data? I wouldn’t have thought it possible for a nosecone to fail before a tube or coupler, but I guess anything is possible. Maybe we could see what altitude it was at, and look for wind shear in the balloon data?

If you can get data off of this, it would be pretty incredible:

Looks like the data already came off of it 😥

So everything forward of the av-bay is missing? What about the chute? Was this in a standard configuration with nosecone/airframe&chute/av-bay/drogue/motor?

Yep, everything forward of the av-bay is missing. The main chute was seen floating towards cheyenne at about a mile. The rocket was basically a standard configuration, exactly as you described.
2011-06-03 at 11:26 pm #54439
SCOTT EVANS
Warren: it shredded on the way up. Apparently, a PR 5 inch nosecone isn’t terribly happy at mach 2.2.

(My fins stayed on though :D)

Is that a fiberglass nose cone? Renforced on the inside?
2011-06-04 at 5:47 am #54440
Chris LaPanse
Fiberglass, yes, but no reinforcement. It was just a glass nosecone stock from PR. It’s been up to ~M1.5 3 times before, and M1.8 once, and never had any issues. Apparently, 2.2 was too much though.
2011-06-04 at 1:53 pm #54441
SCOTT EVANS
Fiberglass, yes, but no reinforcement. It was just a glass nosecone stock from PR. It’s been up to ~M1.5 3 times before, and M1.8 once, and never had any issues. Apparently, 2.2 was too much though.

Well……….maybe it just fell off! 😉
2011-06-04 at 2:38 pm #54442
Warren B. Musselman
Moderator
Perhaps stress fractures from repeated Mach+ flights made it ready to fall apart.
2011-06-04 at 7:41 pm #54443
Chris LaPanse
Definitely not. I looked at it fairly closely before flight, and it definitely wasn’t ready to fall apart.
2011-06-06 at 12:37 pm #54444
Adrian
Participant
More brainstorming: Have you calculated the differential pressure that your nosecone shear pins would have to withstand? Was the nosecone shoulder seated firmly against the airframe, to prevent your shear pins from taking G loads during the boost? Did the failure happen at burnout? If so, differential drag might have pulled the two pieces apart.
2011-06-06 at 4:17 pm #54445
Murdock
Chris,
Heard about your flight, sorry about the rocket.

Mike thanks for posting pics for those of us that didn’t make it out.

-Chris
2011-06-06 at 9:37 pm #54446
Chris LaPanse
More brainstorming: Have you calculated the differential pressure that your nosecone shear pins would have to withstand? Was the nosecone shoulder seated firmly against the airframe, to prevent your shear pins from taking G loads during the boost? Did the failure happen at burnout? If so, differential drag might have pulled the two pieces apart.

The failure was pre-burnout, and the nose was seated fully against the airframe. I haven’t run any CFD yet to determine the pressure on the nosecone though – I definitely plan to do that at some point.
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