I would sand the interior of the BT a little with some 320 grit before I sanded the shoulder on the NC. If you CA'd the BT as you said, a light sanding there won't hurt.
A little late now, but I would have used some Kevlar cord tied to the motor mount with some 1/8" elastic (treated for the heat), rather than the typical Estes "tea bag" shock cord attachment with the often too short rubber band! But that being said, I would still replace the Estes shock cord with 1/8" elastic. I order mine from https://www.apogeerockets.com/Build...t/Shock_Cord?zenid=i9rbh7u0hkvto9ntuc5fdn2rs4, but seeing as you're in Australia, perhaps there's another supplier closer to home for you.
Lastly, you haven't made any outrageous modifications to a proven design, so weighing it and doing simulations in OR aren't necessary at all, unless you just really want to do it. I think all this simulation stuff gets a little out of hand at times, especially on LPR models of proven design. But that's just me, who was around and flying model rockets long before computers became household appliances. :wink:
2) Keeping it legal - the 400ft ceiling for local playing field launches - I would hate to lose it as a launch site because of complaints or rockets ending up on roads etc...
attach the chute about 2 - 6" below the nose cone so the loop on the cone doesn't need to take the weight of the rocket.
Rex
Is this an Australian law? And how can it be enforced? No one I know can stand at ground level and tell me exactly how high my rocket flew.
You need a better understanding of "controlled airspace". If you're 5 miles (8 Km) away from any airport, you've got a lot more than 400' (120 m) of safe ceiling to launch your rockets in. I'm not faulting you for wanting to be a safe, law-abiding citizen, and not draw unwarranted attention to your/our hobby, but don't limit yourself beyond what is necessary. Controlled airspace looks like an inverted cone, the point being at the airport. The further you are from an airport/airfield, the higher the available ceiling is to you.
On the little plastic loop - I don't use it anymore. I drill a couple of holes in the shoulder of the NC and put a loop of Kevlar through that I use to attach the shock cord and the swivel for the parachute. That way I can add a Chute Release and/or AltimeterThree and not worry about the thing breaking. See the picture below.
On the shock cord: I have had perfectly acceptable results using an "Estes teabag" style mount to mount some of the same Kevlar (100 lb. braided) inside the body tube. Then I can tie the supplied shock cord (recent ones are quite a bit longer than they used to be - Estes does listen) to it. The other end can then be tied to the Kevlar loop.
The swivels were the saving grace. It meant I could disconnect everything and I untangle the parachute strings.
Long story short: my 11yo has been asked not to run with the parachute held, spinning behind him... ��
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