First of all I must say that the deciding factor in many if not all of my design/building/material decisions is price, unfortunately I don't have enough money to buy high end fiberglass components and/or kits, I'm barely scraping by for getting the money to afford the size of impulse motor I want. Please let that thought be a guiding factor in the greatly needed advice that may be needed in all aspects of my productions and plans. Now that I got that out of the way on to the rest of the topic...
Here in a couple months I would like to be getting my Jr. LVL 1 certification. I've been in the Process of building my rocket for some time now but a few large problems have been standing in my way.
First of all to start you off with an overview my rocket is being built entirely from scratch, although precisely created I must add. My tendencies for overbuilding and creating overstable rockets are immense. The main body tube is a 9.6cm wide with 4mm thick walls, it's a salvaged fragile object shipping tube that sustained no damage. The nose cone will be turn by me on a lathe out of pine, my prototype nose cone in the picture below was turned out of a 4"X4" but was slightly too small. The fins will be 3/16" or 1/4" ply recessed into the body and adhered to the motor tube as well as short strand glass for fillets and probably foamed internally. All attachment points for parachute lines are U-bolted into the home made (drill press hole cutter) centering rings that also retain the motor mount tube. The parachute is a 5 or 6 foot gym exercise chute (kids stand around it shaking to make balls fly upward like "popcorn") that I need to add lines to.
The motor is a Rouse-Tech 38/600. My reasoning for this was my want to use heavy walled body tubes as well as pine nose cones that I could make and heavy weight rockets in general. I wanted to not have to buy any other casing even for high end LVL1 flights. It's really unfortunate that somebody happened to knock the casing off my table and it hit concrete. So at this point I can get any other 38mm casing but I would like to stay up in the high end of LVL 1 impulses.
The main thing that concerns me is my ability to find someone willing to sign off on a scratch building minor's attempt at level 1 certification. Especially a builder that at first glance appears to want the largest engine without reason.Unfortunately I am related to no one that participates in HPR so things are kinda difficult. Therefore any advice on what I could do to ensure my ability to find a sponsor would be great.
A couple more general questions...
Would 3/16" ply be heavy enough for a 480 N/s motor?
What is a average fin height related to body diameter?
Is there a rule of thumb for parachute:weight ratio?
This is the damage that my casing took from a hard fall. People wonder why I don't have parties anymore...
My slotted fin/motor section as well as the remainder of the tube that the payload section will be cut out of and my practice run of a nose cone and parachute. I began to glass the nose con but stopped after I closer inspection of it's fit with the tube.
"business end" with a motor retention system consisting of recessed T-nuts and mirror hangers. Beautiful job with the epoxy I know, was really proud of that. I began this rocket almost a year ago, my neatness with epoxy has increased tenfold, but the I am sure of the strength of the bond. I'll probably go back and fill in the rest with casting epoxy just for a nice neat look.
U-bolt embedded in spacers on a short piece of 38mm motor mount to connect the parachute line to. The method will be cloned on the forward end or a long threaded I-bolt will be embedded in the nosecone depending on how I decide to extend the body tube to increase stability.