Delay charges

[Forced_Induction]

I'm planning for my next build which I'm thinking is going to be a 3 engine cluster with side boosters that detach before the center core finishes its burn. I think I'm going to use 18mm engines for the outer boosters and 24mm or 29mm for the center. It'll probably start with Estes c6-0 for the sides and an e9 for the center.

Eventually I might try using aerotech RMS engines. This has gotten me thinking about exactly how delays work. Does the delay time begin from ignition, or burnout? I'd imagine the RMS delays start from ignition as they're c grains but the Estes engines being end burners, do they start at burnout?

And secondly, how would I make a 0 delay for an RMS? I think the answer to this is dependant on the first question.

Thanks

Ps, I'm not sure if this fits under MPR, recovery, or propulsion but I figured if it needs to be moved, a mod would.

 

[dhbarr]

C6-5, delay is ~4.5-5.5s after cessation of thrust. RMS delays are sized such that the portion remaining keeps the fire in for dash-X seconds more.

You can't make a dash-zero RMS, the case pressure would rupture the propellant web and the fire would come out both ends.

 

[Bat-mite]

What you can do with an RMS, however, is remove the black powder altogether and plug the forward closure, if that is useful.

 

[cerving]

What you can do with an RMS, however, is remove the black powder altogether and plug the forward closure, if that is useful.

That assumes that you have some other means of deployment, of course. That usually means some kind of electronic deployment, which you may or may not be ready to take on at this point.

The 29mm DMS motors (like the G80) have an adjustable delay up to 14 seconds, that should work for your build. If it has to be 24mm, you might want to look at the CTI 24mm motors, like the 3-grain F79 or the 6-grain G65.

 

[Mr Rocket]

Here's a link to a project that I think is similar to what you are attempting.

https://www.rocketryforum.com/showthread.php?137453-Ventris-SRB