What will happen to the igniter/ematch in this rocket?

[Sparkyflyer14]

As I try to get into duel deployment and air starting, I have come across a problem that I can't make sense of. If the top stage of your rocket also has duel deployment, what will happen to the ignitor that starts the top motor? (Assuming the electronics are in the top stage) I don't know if the rocket in this image was intended as a second stage, but I find it fits the situation I was planning. Note the small tube in the engine mount that the igniter would go through to get to the motor. When the body tube separates for drogue deployment, will the igniter prevent separation, or will it freely slide out of this tube? I am wondering if anyone has experience with this design, or if my idea is simply flawed. If I have not explained myself fully, let it be known. Thanks

 

[mikec]

You generally have to connect the second-stage igniter to the electronics in some way that will allow them to be ripped apart by deployment (loose twisting, some sort of zero-force connector, etc.)

p.s. It's dual, not duel.

 

[fyrwrxz]

Given the tail cone configuration, I'm have a hard time configuring this bird in my mind as a sustainer. There is only one motor I see here. I do not see a coupler designed to mate with a booster section. If you are confusing dual deploy with staging then the main, is usually held in place with friction or better, shear pins. The drogue deployment breaks the streamlining to slow things down. If this is indeed the 'top stage', you will need more than a dual deploy avionics unit or units. Check out the revised 'Tiltometer' used to determine safety, is usually located in the booster section. Some staged birds use a three pyro event controller. The booster section can be treated as it's own vehicle, as it also needs to recover, but possibly without drogue deployment. Your rendering is exceptional! Keep up the mind sims and check thru the posts for airstarts and staging ideas.
Straight smoke and good chutes!

 

[Sparkyflyer14]

You generally have to connect the second-stage igniter to the electronics in some way that will allow them to be ripped apart by deployment (loose twisting, some sort of zero-force connector, etc.)

p.s. It's dual, not duel.

Okay, thats what I assumed. I was only worried that it would disrupt the altimeter in some way if it was yanked on at drouge seperation. And my bad on the spelling.

Given the tail cone configuration, I'm have a hard time configuring this bird in my mind as a sustainer. There is only one motor I see here. I do not see a coupler designed to mate with a booster section. If you are confusing dual deploy with staging then the main, is usually held in place with friction or better, shear pins. The drogue deployment breaks the streamlining to slow things down. If this is indeed the 'top stage', you will need more than a dual deploy avionics unit or units. Check out the revised 'Tiltometer' used to determine safety, is usually located in the booster section. Some staged birds use a three pyro event controller. The booster section can be treated as it's own vehicle, as it also needs to recover, but possibly without drogue deployment. Your rendering is exceptional! Keep up the mind sims and check thru the posts for airstarts and staging ideas.
Straight smoke and good chutes!

Sorry, the boat tail is confusing. Please disregard it and assume that there is a second stage beneath the rendering. I am honored that you think it was me, but the credit for this image goes to apogee components. I was simply using it for the tube that went through the motor mount on the sustainer stage. Please assume that the booster has its own recovery and underwent drag seperation. If a igniter comes from the electronic bay over the uper-stage drouge shute, and then goes through the engine mount via the small body tube and then into the motor, what will happen to the igniter later in flight when the drouge shute deploys?

(Line is Igniter)
(Hopefully this makes more sense)

 

[mikec]

Given the tail cone configuration, I'm have a hard time configuring this bird in my mind as a sustainer.

I've flown second stages with tail cones, though it's a bit of a pain. Simpler to avoid it if you aren't doing minimum-diameter.

I use 100-mil header pins and sockets for the disconnect, that works pretty well. But loose twisting works OK too.

 

[waltr]

I recommend reading through all the 2-stage threads in the 'airstart' section. Lots of good discussions there.

If you have never done DD then do this first on a single stage rocket. There are many things that can go wrong compared to simple motor eject. After you have reliable DD working then think about 2-stage with airstart.

When you read through the airstart threads you will find that very few rocket drag separate the booster. There could be a separation charge fired from electronics in the booster that also fires the chute ejection. Or lighting the sustainer motor separates the booster.

In the sustainer it is common to have two avbays. One in the booster to fire the motor igniter and could also fire the separation charge. Also could fire a drogue charge. It is also a very good idea to have electronics that measure the rocket's 'tilt' and inhibit lighting the motor if tilt is too much. Some clubs REQUIRE this tilt safety.

The other method is as mikec said; one avbay with break-away wires to light motor.

Then a typical avbay with standard DD setup.

With a properly design setup both booster and sustainer will recover safely, chute out, even when sustainer motor does not light.

There are many ways a 2-stage can be configured but always designed for safety.

 

[Sparkyflyer14]

I recommend reading through all the 2-stage threads in the 'airstart' section. Lots of good discussions there.

If you have never done DD then do this first on a single stage rocket. There are many things that can go wrong compared to simple motor eject. After you have reliable DD working then think about 2-stage with airstart.

When you read through the airstart threads you will find that very few rocket drag separate the booster. There could be a separation charge fired from electronics in the booster that also fires the chute ejection. Or lighting the sustainer motor separates the booster.

In the sustainer it is common to have two avbays. One in the booster to fire the motor igniter and could also fire the separation charge. Also could fire a drogue charge. It is also a very good idea to have electronics that measure the rocket's 'tilt' and inhibit lighting the motor if tilt is too much. Some clubs REQUIRE this tilt safety.

The other method is as mikec said; one avbay with break-away wires to light motor.

Then a typical avbay with standard DD setup.

With a properly design setup both booster and sustainer will recover safely, chute out, even when sustainer motor does not light.

There are many ways a 2-stage can be configured but always designed for safety.

Thanks. It does seem like a very complicated setup for a begginer like me. I appreciate your insights. Thats exactly what I am looking for.

 

[Reinhard]

Another option is to come up with a two stage recovery system that only requires one break in the airframe. This way, your avionics bay can always stay connected to the motor. Devices like the Chute Release, ARRD, Tender Descender or line cutters are typical approaches for that.

Reinhard