Greetings!

Returning back to the hobby since many years absent, will be enjoying building and launching rockets with my 5 year old son. I've taken an interest in building as my first mid/high power rocket the 4" Paper Madcow DX3. Since I couldn't find it new from a dealer, I purchased an Aerotech 29/40-120 RMS from ebay along with 6 reloadable motors. I downloaded and ran simulations with these motors, and all appears be good. I plan on obtaining the delay time tool to do any needed adjustment to the motors where the delay is too long. The velocity @ parachute deployment for all except the G64-4W is between 1.16 to 2.05 m/sec. I'm assuming that this is a good velocity range? For the G64-4W engine it states the velocity is 10.8 m/sec - is this too fast for this rocket? I have read elsewhere that 20 to 25 fps is the max . . . What is the generally recognized fastest velocity at deployment for 4" paper tube rockets?

G53-5FJ (works great as is)

G64-4W (I have a question about this one, states ideal is 5.04s)

G64-10W (drilled to 5 seconds)

G76-10G (drilled to 5 seconds)

Another question is the velocity off rod. For the G53FJ it is 13.4 m/sec from a 6' (184 cm) rod. Is this sufficient? What is the minimum? How can I find/calculate that minimum? I found the following statement on NAR from their launch safety pdf: "Best practice would indicate that rockets should be guided by launch rods, rails, or towers until they have attained a forward velocity of at least 4 times the velocity at which the wind is blowing (or gusting) at the launch site" If the wind is still or very low?

Thanks for any advice . . . feel free to point me to published tables and etc. . . .

Mark Sanderson

Returning back to the hobby since many years absent, will be enjoying building and launching rockets with my 5 year old son. I've taken an interest in building as my first mid/high power rocket the 4" Paper Madcow DX3. Since I couldn't find it new from a dealer, I purchased an Aerotech 29/40-120 RMS from ebay along with 6 reloadable motors. I downloaded and ran simulations with these motors, and all appears be good. I plan on obtaining the delay time tool to do any needed adjustment to the motors where the delay is too long. The velocity @ parachute deployment for all except the G64-4W is between 1.16 to 2.05 m/sec. I'm assuming that this is a good velocity range? For the G64-4W engine it states the velocity is 10.8 m/sec - is this too fast for this rocket? I have read elsewhere that 20 to 25 fps is the max . . . What is the generally recognized fastest velocity at deployment for 4" paper tube rockets?

G53-5FJ (works great as is)

G64-4W (I have a question about this one, states ideal is 5.04s)

G64-10W (drilled to 5 seconds)

G76-10G (drilled to 5 seconds)

Another question is the velocity off rod. For the G53FJ it is 13.4 m/sec from a 6' (184 cm) rod. Is this sufficient? What is the minimum? How can I find/calculate that minimum? I found the following statement on NAR from their launch safety pdf: "Best practice would indicate that rockets should be guided by launch rods, rails, or towers until they have attained a forward velocity of at least 4 times the velocity at which the wind is blowing (or gusting) at the launch site" If the wind is still or very low?

Thanks for any advice . . . feel free to point me to published tables and etc. . . .

Mark Sanderson

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