I’ll be documenting my L1 & L2 build as progress is made. I’m designing a fairly “standard” 4″ dual-deploy rocket with a removable avionics bay. I went into this project with two opposing opinions resting on my shoulders. On one side, the opinion says to purpose build an L1 rocket and build another for L2 at a later date. On the other shoulder, building one rocket to fulfill both purposes is the way to go. Weighing both options with my personal bias on things, I’ve since decided I’m simply going to build the rocket I want to build, which will just so happen to be capable of fulfilling the flight requirements (and then some) for both L1 & L2. I agree, dual deploy does add complexity and isn’t required for L1 (L2 either, but it’s “recommended”, so my TAP says). But as an electronics and pyro guru myself, electronics deployment with black powder charges is just a natural fit.
Materials… I’ll be using low-cost 3.9″ LOC tubing for the airframe, with a 38mm motor mount tube. The nosecone will be a MadCow PNC 4″x16.5″ ogive, fairly hefty at just over 10 oz. As for motors, I’ll be able to use everything from an H to at least a J.
Here’s a render from OpenRocket of the design thus far:
Specifications:
- Diameter: 4″
- Overall length: 64″
- Weight (without motor): ~60oz
- Motor: I-xxx (L1) and J-xxx (L2)
- Estimated altitude: TBD
- Fins: 4, 1/4″ plywood – 5 ply from Michael’s ($4.99 w/ coupon)
- Parachute: 4′ Rocket Man (3.5 oz)
- Harness: tubular nylon 9/16″ from REI
2/15/2015
Today I cut the 1/4″ plywood fins. I first printed-out the template from OpenRocket onto some thick paper I had, cut it out, then traced all four fins onto my sheet of plywood. I used my 12″ Harbor Freight band-saw to cut them out just over-sized. I sanded off the rest with a bench sander. The total fin weight equates very closely with what OpenRocket estimated, which was 10.6oz, while actual weight is 10.74oz. Not bad! I did input my own calculated specific-weight of the wood, so that helped with accuracy (I did the same for all my materials… tubes, etc.). I plan on sanding the leading edges to some degree, nothing crazy, mostly to round-over the blunt edges. There will be some aerodynamic advantages to doing that, but if nothing else, the paint will stick better!
*Pictures to be added shortly*
