L1 in my future

Closeup of the fin fillets. Technique was: masking tape to mask off the channels, dribble thickened 105/205 in as neatly as I can, smooth with a plastic spoon, minor touch up to remove any flow. The spoon has just the right radius to make a near perfect fillet. The excess mostly winds up on the masking tape, which I peel off after about 30 minutes or so. 4 of the 6 fillets were done with this technique, the first two were done by hand and are not quite as pretty.

Nicely done! The first few times I did epoxy fillets I didn't worry so much about getting them smooth at first, figuring "I'm going to sand them anyway." Then after sanding/filling/sanding/sweating/resting/sanding a few cycles I learned that taking a little extra effort to smooth the fillets is well worth it. Dipping your spoon, gloved finger, PCV segment, or whatever in a little denatured alcohol before smoothing works well too.

Thanks John! Couldn't agree more that the sanding is very tough. I have one fillet that has a high edge on the fin side - thinking of carefully taking the Dremel to it because the hand sanding is very slow going. Looked back at the other one that I did by hand and it's actually pretty nice - so 5 out of 6 ain't bad!

Putting the finishing touches on the Super DX3 - Still to do are: adding nose weight to the cone, painting, installing rail buttons and engine retainer.

On the side, I'm working out some flight calculations and wanted to ask if anyone has experience with a particular motor (the Aerotech H123W-M). If the published stats on the Aerotech website are correct, it should have enough thrust to give this (fairly heavy - estimate 65 ounces once I get the nose weight in place) rocket a stable flight. I'm seeing other stats though on rocketreviews.com that show its average thrust as 81.3N - considerably less than the manufacturer's figure of 123N. If those figures are correct, then it's borderline (if you go by the 5:1 T:W rule).

Has anyone used that motor or equivalent with a similar rocket, and what were the results?

Thanks,
- Matt

Thanks Bill.

The rocksim file that I'm using (in OpenRocket) also is based on the 1999 thrustcurve data, so I'm going to accept it as true.

I'm seeing two potential issues from the simulations and my hand calculations. Velocity off rod seems low at 11 m/s. Also, it appears to be moving at a pretty good clip when the chute deploys (25 m/s) since it's past apogee on the 10s delay charge I have. In simulations where I use a 6s, delay I'm seeing deployment very near apogee with the bird moving at around 9 m/s - so the delay drilling tool for Aerotech charges might be a good investment.

So, is 11 m/s too slow off the pad?