Need help on launch lug sizing - Northern Colorado Rocketry

This topic has 67 replies, 9 voices, and was last updated 19 years ago by Warren B. Musselman.

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April 27, 2006 at 3:43 pm #42073
Ken Plattner
Participant
Thanks. I was wondering about the ignitors – I read they weren’t too reliable. Didn’t know about the level 1 cert though. I’ll get my paperwork in order for that. Interested in being a witness?
April 27, 2006 at 10:04 pm #42074
Chris LaPanse
Another (much cheaper) option than the first fires are Quickburst. Unfortunately, they are gone until the first of may, so so may have to eat the cost of the first fires for Mayhem, and then go to the others later.

Another option is to dip your own, but whatever you do, don’t use copperheads.
April 27, 2006 at 11:09 pm #42075
denverdoc
Xman,

Love to be a witness, but make sure that there is nothing that prohibits flying a cluster for L1. I know its an issue later on, but can’t recall re L1.
J
April 27, 2006 at 11:13 pm #42076
Warren B. Musselman
Moderator
NAR can’t use clusters to certify, Tripoli can.

Warren Musselman
April 27, 2006 at 11:28 pm #42077
Chris LaPanse
However, not on 3 G’s

It has to have one motor in the cluster at least that is in the certifying class.

So an H and 2 G’s would be OK, but not 3 G’s.
April 27, 2006 at 11:52 pm #42078
denverdoc
Well xman’s project just got a lot more interesting, assuming the usual equilateral triangular cluster, the X has no choice but to swap rockets–maybe for economy a separate fin can that keeps all else the same, or gulp, cluster H’s. That would be about as ballsy a L1 cert as I can imagine, esp when new to HPR. Would not recommend it, esp on sat.
JS
April 28, 2006 at 12:06 am #42079
Chris LaPanse
He could do 3 H128’s.

That’s still within the limits of L1.

Still, it is definitely a challenge, and would make for an interesting cert attempt.
April 28, 2006 at 12:28 am #42080
denverdoc
Maybe Xman can post some construction info. 80+ # of thrust for an up til now E flyer seems strong, but if everything is epoxied and the fins aren’t balsa or bass, it has a chance.
J
April 28, 2006 at 3:57 am #42081
Chris LaPanse
Oh – absolutely agreed, which is why I stated it would be an interesting and challenging attempt, but doable.
April 28, 2006 at 3:56 pm #42082
Ken Plattner
Participant
If either of you have RockSim I can email you the design. Here are the basics though:

Length: 65″
Diameter: 4″
Span diameter: 14″
Mass: 53.5 oz (no motors), 66.3 0z. (with motors)
CG: 31.9″ (as measured from the top)
CP: 50.5″ (margin 4.6)
Airframe: PM Kraft Phenolic
Fins: 1/8″ Birch aircraft plywood (through the body). Area between the first and second rings will be filled with foam to stablize the fins.
Plastic nose code (PM)
1/4″ plywood clustering rings

I used epoxy on all gluable parts. The only thng not shown on the design are the rail buttons, but these shouldn’t have a large affect on the CG/CP positions.

According to the NAR website, I might be able to cert on weight alone (their req. is 53 oz – don’t know if that includes engines or not)

kp.
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