2 stage drag separation in OR

[davdue]

Is there anyway to determine if the aero drag is enough to separate a booster from the sustainer in OpenRocket? I built my L1 cert rocket to be a 2 stage rocket after my cert. I can't attach the ORK file because it is too big at 313K. Not sure what to I can do to make it smaller. I could email if necessary.

 

[mikec]

Is there anyway to determine if the aero drag is enough to separate a booster from the sustainer in OpenRocket?

Not that I know of directly, though you can calculate this from drag force information. See post #4 in https://www.rocketryforum.com/showthread.php?t=25439 for some guidance on this, though many will suggest that using drag separation is somewhat uncertain.

 

[davdue]

So the solution would be some sort of small charge to separate the booster from the sustainer. I was planning on using the PerfectFlite MiniTimer3 to light the sustainer. I wonder if it has the power to light two matches? I could put the sustainer igniter and the charge igniter on the output. The problem there would be if the motor lights before the charge goes off then you take a chance burning the booster. I would coat the booster coupler liberally with JB Weld either way. I guess the other solution would be an inexpensive altimeter like the adept22 and set one output for time delay and the other for a little bit longer to allow the booster to separate. I plan on the booster engine ejecting the laundry.

 

[JDcluster]

I don't even like the idea of drag separation. I have only flown 2 HP 2 stage rockets both of them employed a separation charge of 1/2 to 1 gram charge.
That was for a 3" and 4" rockets. The idea is to drop the booster at burnout, then ignite the upper / sustainer about a sec from a second channel or from a different flight controller.



JD

 

[JDcluster]

You can wire both the sep charge and the sustainer motor to the same timer flight controller. It takes about a second for the motor to come up to pressure giving a little gap.

I wouldn't use an Adept 22 as it is intended for chute deployment.
Your rocket would be arcing over before anything happens.

A Missile Works PET2 would be a better choice.

JD

So the solution would be some sort of small charge to separate the booster from the sustainer. I was planning on using the PerfectFlite MiniTimer3 to light the sustainer. I wonder if it has the power to light two matches? I could put the sustainer igniter and the charge igniter on the output. The problem there would be if the motor lights before the charge goes off then you take a chance burning the booster. I would coat the booster coupler liberally with JB Weld either way. I guess the other solution would be an inexpensive altimeter like the adept22 and set one output for time delay and the other for a little bit longer to allow the booster to separate. I plan on the booster engine ejecting the laundry.