Balsa:
Balsa is one of the biggest variables in model rocket kit construction. We use balsa sheets that vary from 8 pounds per cubic foot (pcf) to 14 pcf, with an average of about 10 pcf. Generally, the more dense balsa is harder. Tolerances of the 1/16", 3/32", and 1/8" sheets that we use are +/- .010". We discard balsa that is at the low end of the scale because it is much weaker. The type of grain can affect harness as well. We also discard most of the A-grain balsa because it is significantly weaker and warps too easily, particularly in the 1/16" sheets. Most of the balsa sheets we use are B-grain. Since Balsa is from living trees, it is never perfect. Knots, insect holes, and diseased sections are some of the imperfections we look for and reject when laser-cutting the fins. Man-made imperfections like saw marks, machine handling marks, and areas with improper sanding are other reasons for rejecting balsa sheets.
In any case, we will replace any fins that are not up to our (or the customer's) standards.
Parachutes:
The Hydra VII has three 12" chutes, two for the booster section and one for the payload section.
Augmenter fins:
The 12 augmenter fins provide a significant amount of surface area to move the Center of Pressure rearward. If they are left off, some weight must be added to the nose cone to keep it stable. If they are replaced with heavier material, the nose cone may also need additional weight.
. The balsa is way too thin, and the grain is going the wrong direction. I would use 1/32nd birch or plywood....
