Aside from the questions, there are clearly some thing you want to know about. I'll do my best to deliver:
July 10th: "Aerotech G71 vs G77":
The G71 and G77 are fairly similar motors. Both are Redline motors, with the awesome laser-red flame.
The G71 is a reload for the 29/40-120 hobby case. Its impulse is 107 Ns, at it contains 56.9 grams of propellant. It comes with delays of 4, 7, and 10 seconds.
The G77 actually comes in 2 slightly different styles. One is a reload for the 29/120 case (different from the 29/40-120). It is 105 Ns, with 58 grams of propellant and available delays of S (6 seconds) and M (10).
The other is a single-use motor, available in preassembled and loadable (different from reloadable) varieties. It contains 58.1 grams of propellant which generate 102.9 Ns of total impulse; available delays are 4, 7, and 10.
The bottom line: If you have the 29/40-120 hobby case, use the G71R reload.
If you have the 29/120 case, use the G77R reload.
If you have neither, use the G77R single-use motor. Choose the loadable variety if you want to save money and don't mind spending a few minutes building the motor.
July 12th: "best glue for ttw fin fillets mid power high power hpr rocketry":
Are you using fiberglass? If so, use epoxy.
Are you using carbon fiber? If so, use special high-temperature epoxy for carbon fiber.
If not, it depends on the application. For most uses, wood glue is excellent. It bonds excellently to paper / cardboard and all varieties of wood. It's incredibly strong, safe, and easy to use. It's cheap, sands well, and you can spread it into fillets with your fingers. It's slow to dry, though.
For attaching plastic, fiberglass, carbon fiber, metal, Blue Tube, or Quantum tube, epoxy will work better. It dries quickly and attaches almost everything. But, it'll stick to you, and it can cause allergies, so use *nitrile* (not latex) gloves.
A good compromise for larger rockets that need a lot of strength may be epoxy clay. It sets up rock hard, gives you plenty of time to precisely shape your fillets, and attaches anything. But it's expensive, and too much will be heavy.
July 12th: "blue thunder propellant formula":
Blue Thunder is a high-solids blend that burns very efficiently, with little smoke or colored flame. This indicates that it's almost pure ammonium perchlorate / aluminium blend, with few additives. I know very little about motor making; this site may be of help.
UPDATE: Thanks to Ken Kzak:
Blue Thunder is a high-solids blend that's mostly ammonium perchlorate and binders (PBAN and HTPB). Wikipedia gives one common recipe for high-performance, low-smoke motors as around 80% AP, 18% binder, and 2% metal. For Blue Thunder, that metal might be aluminium, magnesium, or copper.
July 13th: "rocksim file for madcow 2.6 patriot high powered rocket":
Madcow are awesome folk; I highly recommend their kits. On their page for the 2.6" fiberglass Patriot is a convenient link to the Rocksim file.
July 29th: "wisdom is knowing that you'll be an idiot in the future which qc comic":
Number Nine Hundred Seventy-six.
For the future, Ohnorobot is extremely useful, and searches over 100,000 panels of over 1700 comics.
Dataviz of the Month – March 2024
1 week ago