I tried a pm and it did not send. I am not an expert but feel comfortable discussing it and I think I can help you out.

feel free to contact me directly

jamesr2 at gmail dot com

I have successfully staged a HPR rocket and it is a learning experience. I also have in the works a larger two stage rocket. I can try to help.

Doug

I would like to pick the brain of a NCR staging expert. My project is a Quantum Leap 3000. I have too many questions to post here. Thanks.

I can tell you, if you have the quantum tubing(plastic) dont use 2 grams of powder for ejections, like I did and get a larger main chute that packs tighter than mine did (you will need the room). See my failure in the december launch log. 😥 Before you worry about the staging, launch the sustainer first by itself to make sure you have the duel deploy down. If it fails at least you will have the butt left. Like me. 😉
I was waiting to buy the staging timer (so at least I wasnt out those dollers)
Scotte

I purchased my QuantumLeap in phneolic and then fiberglassed the body tubes. I am struggling with this drag seperation of the booster and with the interstage coupler(with timer) attached to the booster , how do you set timing so the sustainer motor gets lit before seperation? ❓

you will need to make sure you have a snug enough of a fit that it does not separate until motor is lit, the pressure of the motor lighting will pressurize the inter-stage coupler causing it to separate. You can also help things along by putting a small amount of ffff in a corner of a plastic sandwich bag and put that in the inter-stage coupler and when the motor starts to light you will then have the BP cause or help with separation. this can cause other things to deal with, shielding the inter-stage coupler so that it will last though multiple flights. lots of things can be done for that.

when you run your igniter wire from timer to motor you do not want to cut it and you want to use the longest one you can find. you want to coil up the extra wire in the inter-stage coupler so if you start to get separation you do not pull the igniter out before the motor is lit. this is why it is much better to have the timer in the sustainer and not in the booster and you can also delay lighting the motor well after separation reducing drag and maximizing altitude.

I am struggling with this drag seperation of the booster and with the interstage coupler(with timer) attached to the booster , how do you set timing so the sustainer motor gets lit before seperation?

Drag separation almost never happens. It is almost always the ignition of the upper stage that blows off the booster. A friend of mine build a 4" version of the Estes Omega with big draggy fins, used very high thrust first stage motors and still it would not drag separate. He had the interstage coupler so loose it practically fell off before he could get drag separation. He added holes in the upper part of the interstage coupler to allow the pressure to vent as early as possible.

I use friction fit for my interstage coupler but I use a black powder charge to blow off the first stage before I lit the upper stage. I hope this helps.

Doug

Doug it right it does not happen that often, you also have to remember if it does not light you are using electronics that will deploy chutes with or with out the ignition of the upper stage as long as you hit the minimum altitude to arm.

Doug made a good point, you do want to vent the inter-stage to help with ignition, it is like cutting a hole in the cap of an AT motor.

I found my firends web site but there isn't that many pictures. I'll post it here for anyone that is interested.
http://www.dmf-rockets.com/omega4/omega4page.html
He did get many, many flights on that rocket in part because of the vent holes. If you don't have them you run the risk of overpressurizing and breaking something. The booster parachute was deployed with the motor ejection (about 6 second delay).

Doug

I have never staged an HPR (that is the disclaimer 😉 but I would have to say that the majority of big, staged projects I have seen have had very significant intervals between burnout of the booster and ignition of the sustainer - and that they were typically forcibly separated. Granted, this is at places like Black Rock when folks are going for a zillion feet of altitude... That of course also means that the ignition of the sustainer must happen from a timer that is aboard the sustainer.

Bo V., who used to fly with us, routinely separated stages and let the sustainer coast for 3-5 seconds before lighting it. That guy had it down to a science. He even flew a 3 stage project - "TNT".

I plan on having a 4" rocket flying by Oktoberfest.

Based on an Aerobee 350.

Booster will be an H motor. The sustainer 3 29mm.

The booster will be 3" and the sustainer will be 4".
PET2 timer. All engine ejection.

I will be glad to see some info on staging come up.

With the configuration of the PML kit as is I would have to redesign the electronics bay to make room for the timer in the sustainer. Another question I have is the booster ejection timing. On a Cessaroni I can lengthen the timing so seperation has for sure occured but what if I use an Aerotech motor in the booster?

Missile works PET is basically two timers in one, I have used it air start to different sets of motors, they work great.

I think you are asking on how do you recover the booster then, I would use electronics but there are different delays and AT has certified delay cutting just like CTI, if you go to their web site you can find the details.

Sparky, a minor but important point. You cannot lengthen ANY delay, you can only shorten them. If you want a longer delay for an AT motor, you buy the long delay for that motor. If that's too long, you use the Aerotech tool (just like you would with Cesaroni) and shorten the delay by drilling a small hole in it to the appropriate depth for the length delay you desire.

Warren

I just got a Cosmodrome Aerobee Hi kit and it doesn't come with instructions for staging electronics. If anyone knows someone or has built and flown this kit themselves I would like to know how you configured the electronics. Being new to high power I thought for sure someone here would have a good set up that they like and trust to use. The booster is separated from the sustainer by three struts connected to an interstage coupler that goes inside the sustainer, definately no Estes gap staging here! That is when you know you have taken that giant leap forward in the hobby and stepped up to a new level of complexity.

How do you then ignite the sustainer? Will a 9v battery ignite an Aerotech First Fire Jr. igniter? What do you use? From what I have read so far in this forum the construction method would look like this: (1) sustainer will house the timer, (2) the booster will have a motor with an ejection charge that will deploy it's own parachute, (3) the sustainer will blow off the booster. In this configuratiion it looks like the timer needs to be set to ignite the sustainer before the booster motor pops a paracute.

Thanks for any info especially on what battery and igniter to use for the sustainer.

Robby