AeroTech/Quest at Virtual NARCON 2021
 

For those who didn't watch the Virtual NARCON 2021 Manufacturers’ Forum last night, here is a link to the AeroTech/Quest/RCS presentation:

http://www.aerotech-rocketry.com/up...sentation. pdf

Great news! Thanks, Gary!

Thanks, Gary!

That is genuinely exciting and interesting.

I really, REALLy wish there was a reliable and practical way to stage composite motors. There are so many mid-power projects I'd dig into if that happened.

I do too.

surely in the 21st century ATQ can and will figure this out.

you know I may have just figured this out,. Attached is a drawing I made back in 2005 when I was pondering how to stage composite motors... It's a total rough draft but bear with me.

Composite Motors 101:

As we all know when you ignite a composite motor you also ignite the delay train at the top of the core. This delay has 2 functions:

1. act as a delay train and
2. act as a pressure seal

So the delay train can only be so thin as to contain the combustion chamber pressure and ie you get thrust in return.

so the delays equal the burn time of the motor in question along with the actual delay time. Looking at ATQ's Master Motor listing I notice that only a handful of motors have a 3 sec delay while the biggest number of engines have a 4 sec delay.

this tells me this is the minimum delay time length that can be used by these motors is on the order of 2 to 3 sec max. this also defines the minimum length of the delay train that can contain the chamber pressure.


so if you look at my drawing here's how I would ignite an upper stage motor.

notice that you have a tube that goes through the middle of the delay train...... this tube could be made out of whatever material that might be suitable. this tube would have a faster burning delay train in it than is currently used. the length of the tube and it's diameter would determine it's burn rate.

The actual delay train in the boost engine could be removed entirely and replaced with a circular plug in place of the actual delay train which would hold in the pressure.

But the small diameter delay train would be ignited when the boosted stage engine is ignited at it's top as usual.

The small diameter tube would basically be a composite igniter and it would burn hot enough to ignite the upper stage propellant/delay train as would an electrical igniter.

The question is what composite propellant to use in this composite engine igniter.
It would have to adhere to the sum of the engine burn time plus maybe 1/2 second.... so it would have to be a fast burning composite, perhaps warp 9 or a derivative of this.

Another question is: what do you make the composite igniter tube of? Something strong enough to contain the composite delay train burning pressure but also would be incinerated upon the upper stage igniting and not clogging up the nozzle....... so maybe some kind of coating instead of a physical tube.

Now, this design technique would work on RMS but then there's a question of how you would implement this on single-use motors. I'm sure using this idea as a baseline that something could be worked out.

I will expect royalties if this idea works. :chuckle:

Or just do it with electronic staging 😉

Electronics
 

Not everyone wants to mess with adding electronics, electronic bays, batteries, external controls and switches, testing and arming modes, and all the rest. Many of us enjoy the simplicity of old-fashioned pyrotechnic staging.

+1000 to what olDave just said above.
A LOT of us have no desire to mess with any electronics whatsoever for staging, ejection, or anything else in their hobby rocketry. An altimeter is about the max electronics that I deal with.

Perhaps someone from Aerotech can chime in, but I successfully drilled an F40-4W down to less than a second delay from burnout - story here:
https://www.oldrocketforum.com/showthread.php?t=18716
In short, staged a composite F40W to a BP F15-6 on an Estes Mammoth, using the F40W ejection charge to light the F15. Worked like a charm. My intent was for the ejection charge to fire less than a second after burnout - which is just what happened.

My concern with doing that AP to AP is that AP is far harder to ignite than BP - I don't think 4F black powder will reliably ignite AP. Perhaps if some small bits of AP propellant were added to the BP ejection charge?
I'd certainly do some ground testing before I tried flying it...

thta's what my idea encompasses....the actual delay would be replaced with a plastic plug that has running down the center a smaller diamter tube that goes up into the throat of the 2nd stage. this smaller diameter tube contains a fast burning composite that is the new delay charge....it should be hot enough to ignite the 2nd stage.