AP Staging Questions

I wasn't sure where to put this thread. I decided on Scratch Built, since the rocket will be scratch built. Moderators, if it should be somewhere else, please feel free to move it.

One of my BAR goals is to build and fly a two stage rocket with AP motors. I'm not talking something extreme, just a 3" upscale Omega, on G to F (or G to G) reloads. I thought it would be as simple as adding a timer for sustainer ignition, but after reading this thread, I'm not so sure (and more than a little confused). They're talking about separation charges, altimeter eject, altitude checking, etc. Does it really need to be that sophisticated to be safe? I understand the use of altimeter eject to prevent lawn darts, but my head is swimming trying to grasp all the other concepts.

I've looked at timers from Adept, Perfectflite, Missile Works, and PML. Some are timers only, some have G-switches, some have other features. I've also looked at the Raven, but I'm afraid its capabilities might be beyond my capabilities. I already have an Adept 22 altimeter that I could use for deployment. But I'm unsure how to choose a timer (or electronic stager).

I'm also confused about the design of the rocket. Do I house the timer in the booster or sustainer? From what I've read, it needs to be completely sealed from all exhaust and/or ejection gasses. Would I use a sealed av-bay? Or can I make a compartment somewhere? I was initially thinking of putting it in the sustainer under a removable forward centering ring, and padded with foam rubber, but I don't know if that would even work.

Obviously, I'm open to any and all suggestions and opinions. And if any of you know of any threads or other online information, please feel free to point me to it.

View attachment Omega_3in.ork

Start here. https://www.publicmissiles.com/images/PMLStagingFAQ.pdf

There are two ways to do it, a timer in the first stage or a timer or more capable flight computer in the second stage. I've always done it the second way and it can be safer that way, but it's slightly more complicated.

I highly recommend the Missile Works Pet2 timer. While I've never used one, I've heard tons of great stuff about them, and the price tag is really nice!



Braden

Also look here for a discussion of safety-related issues for airstarts:

https://www.rocketryplanet.com/forums/showthread.php?t=6757

In the F-G range, a 2-stage flight that goes wrong isn't as big a deal as when high powered motors are staged, but I think these issues are still worth being aware of.

https://www.rocketryforum.com/showthread.php?38851-Timers-and-Altimeters
Try this thread.

qquake2k said:

I'm starting to think this might be a little too complicated for me. I'm not much into complex projects, that's why I haven't done dual deploy yet (although that's another of my BAR goals).

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A dual deploy setup would be a great place to start- you don't need a giant rocket to do it, either. I built a 38mm rocket a while back that I love to fly dual deploy on F and G motors.

chadrog said:

A dual deploy setup would be a great place to start- you don't need a giant rocket to do it, either. I built a 38mm rocket a while back that I love to fly dual deploy on F and G motors.

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+1 I learned dual deploy in an Estes Vagabond before setting it up in a 38mm HPR. With a tiny DD altimeter like the Raven with the small lipo batteries it really opens up your options. You could even practice electronic staging on a BP model rocket.

chadrog said:

A dual deploy setup would be a great place to start- you don't need a giant rocket to do it, either. I built a 38mm rocket a while back that I love to fly dual deploy on F and G motors.

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Neuport said:

+1 I learned dual deploy in an Estes Vagabond before setting it up in a 38mm HPR. With a tiny DD altimeter like the Raven with the small lipo batteries it really opens up your options. You could even practice electronic staging on a BP model rocket.

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I have a rocket that's already set up for dual deploy, a LOC Hyperloc 835. I even have an I600 motor and an Adept 22 altimeter. I just need to stop being so lazy and get it all going. It's just that there are so many small details.

qquake2k said:

I have a rocket that's already set up for dual deploy, a LOC Hyperloc 835. I even have an I600 motor and an Adept 22 altimeter. I just need to stop being so lazy and get it all going. It's just that there are so many small details.

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It sounds like you are all set. Go for it!

I was glad to have the practice with a few ounce cardboard rocket before I flew a few pound fg one. It gave me more confidence and I still fly it that way because it only costs a few dollars for BP E engines and I can be frugal at times. Your thread has inspired me to add a BP electronic staged rocket to my build list.

The funny thing is I have only flown a few AP motors so far, G-J, but none have used motor eject. I should add that to me todo list as well. Will probably fly my Jart motor eject. I think I am doing the BAR thing backwards.

I have a USR Sonic 2200 and it is not far different from the scale of what you want to do. Scroll down a bit on this page and you can see a pic of the rocket and yours truly . https://www.v-serv.com/usr/kits/sonic2200.htm

My latest approach has been to use a single event timer and an altimeter mounted in an av bay at the midpoint of the sustainer airframe (which is where the lower and upper airframes of the sustainer are coupled together). The timer has leads that run down to ignite the motor, the altimeter has leads to eject the chute. I am using the cheap Adept altimeter (the one that doesn't report altitude, so I guess it is really just a deployment controller) and a Perfectflite timer with G-switch (this is well worth the money - the built in G-switch is sweet). Both the timer and deployment controller are armed by switches built into the av bay and they have audible continuity so I can tell everything is Ok pre-launch. The timer is set to 3 seconds after liftoff.

Originally I tinkered with using a separation charge to kick the booster off before second stage ignition...this is unnecessary and caused my rocket to veer off vertical when the charge went off. Just use the motor ignition to kick them free...make sure to have some vent holes in the interstage area to vent the motor gases and it is a good idea to use some sacrificial coupler tubing on the inside to take the blast.

I have been using an F52-4 in the booster and the CTI F41SS up top due to easy ignitability. Now that I have some better ignitors I think I'll do F52 staged to G53FJ. Black smoke looks good in an airstart!

PM me if you want pics of the Av bay assembly.

Jason

Jim you already have the LOC 835 so I would start with that. Once you do your first DD, you will see just how easy it is. It only looks intimidating but really is simple. With that 4" Av-bay your gonna have plenty of room for your wiring and all. Here' is some pics of my 2.5" and two 3". I'm working on a 4 inch now that I plan on having two altimeters, one as a backup. I used graphite arrow shafts to slide my sleds over the all thread and I have a couple different types of switches also. There are no set rules as to the materials you use for charge cannisters and switches. Every one does it slightly different. I also use servo connectors like these https://www.ebay.com/itm/5-x-JST-Co...Control_Parts_Accessories&hash=item2316ed089a. They make working inside the av-bay easier. Once you get familier with doing a DD setup you will feel a lot less intimidated moving into staging. Oh yeah, you can find a lot of the parts needed at Radio shack and on Ebay.

qquake2k said:

I'm starting to think this might be a little too complicated for me. I'm not much into complex projects, that's why I haven't done dual deploy yet (although that's another of my BAR goals).

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Heck, start out using a B or C motor and an Estes Mongoose e.g.. Easy as 1 2 3

That's what I did:

[YOUTUBE]_a9jO_8XR08[/YOUTUBE]

Composite Staging Mid Power,Hello Jason, I should have looked around more first I posted a thread on Mid power asking for ideas on staging. Never had any clear knowledge about composite staging. But what I had thought up was just what you spoke of in this post.( for QQUAKE2k) Using the sustainer ignition to separate with vent holes. (using sacrificial tubing for protection I hadnt thought of). What kind of a fit does the booster need with the sustainer at the coupler. It needs to handle the force of a 2 G80 motor cluster minimum.
Thx for your time
EdView attachment 187029

Dual deployment isn't prohibitively difficult or expensive. You might enjoy my Level 2 in Style video, which includes a section on that subject.

Just to be clear, staging with composite motors cannot be done using the ejection charge of the booster (as with BP motors), you must use an electric match augmented with pyrogen triggered by electronics. The electronics can either be timer-based (n seconds from liftoff) or accelerometer-based (n seconds after booster burnout). The G-Wiz units are great for this (I used them in my Comache 3 upscale), but hard to find these days.

Captain i wrote an article for apogee that has some of the info your looking for. Hope it helps

https://www.apogeerockets.com/education/downloads/Newsletter364.pdf

More great info .. Thanks guysView attachment 187318

I've also got an Apogee newsletter article about staging mid-power rockets with either an AP or BP motor in the second stage.

https://www.apogeerockets.com/education/downloads/Newsletter289.pdf

I have some more information on Rocket Reviews for the Standard Missile with a 24 mm AP second stage. For the smaller motors I have never used a staging separation charge. That is too complicated and not necessary for the smaller motors.

https://www.rocketreviews.com/plans---launch-pad-the-standard-rim-67a-bob-morstadt.html

Here is another Rocket Review article for a Bumper Wac with electronic staging to a BP motor.

https://www.rocketreviews.com/estes-v2-bumper-wac-bob-morstadt.html

I have staged Sandman's Nike Hercules model to a BP second stage with electronic ignition, but I don't think that I have a complete write-up for that modification.