Potentially novel use for micromax engines

Gap staged rockets with a long gap/booster segment tend to come in ballistic rather than tumble. Wouldn't take much, even a small streamer, to prevent this. Would it be possible to cluster a micromax engine with a standard, say, D12-0, ignited simultaneously on the pad, so that the micromax ejection charge deploys a chute or streamer AFTER booster sustainer separation?

3 problems
Would micromax burn time plus delay (do micromax engines even HAVE a delay?) exceed the burn time for the D12-0?

Would there be a problem cluster igniting the micromax and D12 (would difference in Ignitors prematurely ignite the MMX?)


Is MMX ejection charge sufficient to deploy a rear ejection pod with a streamer?

Of course, there is something just wrong about clustering a MMX with a D12. Cute, but wrong:smile:

I know from experience that the D12 and C6 motors have almost exact same burn times, if MMX motors delays are long enough the burn time is not as important since they would really be riding along for ejection activation.
Micromax motors are .75 second burn plus .5 second delay. IIRC D12 has a .6 second burn, so booster would stage then .6 seconds later the mmx ejection charges go off.

rharshberger said:

I know from experience that the D12 and C6 motors have almost exact same burn times, if MMX motors delays are long enough the burn time is not as important since they would really be riding along for ejection activation.
Micromax motors are .75 second burn plus .5 second delay. IIRC D12 has a .6 second burn, so booster would stage then .6 seconds later the mmx ejection charges go off.

Click to expand...

Well: your not quite correct on the MMX-II AVERAGE burn times. the AVERAGE actual burn is. 772sec. but the AVERAGE actual delay is .857seconds giving a total of 1.629sec to ejection. The AVERAGE burn on the standard D12-0 is 1.65sec. So you are only talking about .021sec. between both burnout-Burst/ejections. more important, several of the tested motors had a longer Delay (.991sec.) a few had shorter delays of .71sec. Would that make MMX-II motors a NO-Go option, I don't think so particularly if using small streamers instead of Chutes. Also having a bit longer shock-line would allow the booster to separate and slow slightly as the streamer unfurls. I've used micro's to deploy streamers on C6-0 models but truly haven't had a reason to used the system on a D12-0 Boosted model but if the C6-0 & D12-0 have the same burn time there shouldn't be any problem.

Micromeister said:

Well: your not quite correct on the MMX-II AVERAGE burn times. the AVERAGE actual burn is. 772sec. but the AVERAGE actual delay is .857seconds giving a total of 1.629sec to ejection. The AVERAGE burn on the standard D12-0 is 1.65sec. So you are only talking about .021sec. between both burnout-Burst/ejections. more important, several of the tested motors had a longer Delay (.991sec.) a few had shorter delays of .71sec. Would that make MMX-II motors a NO-Go option, I don't think so particularly if using small streamers instead of Chutes. Also having a bit longer shock-line would allow the booster to separate and slow slightly as the streamer unfurls. I've used micro's to deploy streamers on C6-0 models but truly haven't had a reason to used the system on a D12-0 Boosted model but if the C6-0 & D12-0 have the same burn time there shouldn't be any problem.

Click to expand...

I just used the numbers as quoted on Quest's website for the MMX motors.https://www.questaerospace.com/cgi-bin/commerce.exe?preadd=action&key=5631 and I didn't recall the D12's or C6's ( 1.65secs and 1.86secs respectively) numbers very well at all, my bad. As for the D12 and the C6 they work fine together since the C6s have delays long enough that a stable booster will continue up on a ballistic arc until it A) reaches apogee or B) the recovery starts deploying. The most important thing I found out about 18mm motors is dont use the same delay (in both motors) as the simultaneous ignition of both ejection charges can rupture Estes airframes.

I should have guessed you'd done this before, John.
Any issues getting simultaneous ignitions between the MMX Ignitors and the standard Ignitors....errrrr, Starters?

BABAR said:

I should have guessed you'd done this before, John.
Any issues getting simultaneous ignitions between the MMX Ignitors and the standard Ignitors....errrrr, Starters?

Click to expand...

Not at all using pyrogen tipped igniters. I've been using my own 30ga nichrome igniters dipped in a combination of NC lacquer & Pyrodex. This combo seems to be just as quick as the pyrogen used on Quests Q2g2 igniter I use in most of my standard 18 and 24mm clusters. Most of my own personal Cluster igniters are 30ga Nichrome in a APCP combination which is a bit slower burn with a hotter spark, mostly used in D12 clusters. but the dipped tip of these APCP Igniters usually dry to large for use in MMX motors where the NCL/Pyrodex is nice and thin fitting the tiny MMX-II nozzles just fine.

I need to correct some erroneous thinking Rick:
Been flying 2-12 motor BP clusters for over 45years with more the 2100 logged clustered flights. In all those flights and countless clustered flights by other Cluster nuts like myself, it has been absolutely proven that NO two BP motors CAN ignite and burn at exactly the same rate, have exactly the same amount of delay and/or ejection charge materials, let alone obtain "simultaneous ignition" given the variance in heating time (milliseconds) of igniters, controller wire resistance, wire length,type of connections, number of twists in the wire and so on and so on. As a perfect example of this process is the fact we can count the Pop, Pop, Pop, Pop's of our BP motor clusters as an early indication of how many motors in the cluster lit. It's all those little variances that make the ejections difference.
If you have ever burst an Estes .013" or .021" thick craft-tube Air-frame it was due to some other factor then multi motor cluster ejection charges.

Our BP motors simply do NOT eject simultaneously. Some may come pretty close but NEVER and I mean NEVER at the same instant or even close enough to create a concern about over pressurization of a Craft-tube body.

While we can get cluster ignitions within about 5 ms with the use of HD Gel-Cell at the launcher and Relay ignition systems that's as close as we've ever come up with in combinations of 13, 18 & 24mm BP motors. About 4ms +/- on 7 micro motors clusters. Even motors from the SAME purchased package do NOT burn at the exact same rate. don't believe that? just look at the NAR's Motor cert. data on-line. most give all the data for each motor in a test batch (usually from the same RUN of manufactured motors). The mass and average data vary just enough to make things very interesting. and show clearly NO two produce the exact same results.

This is another reason it is of utmost importance to engineer our recovery deployment system to activate with the pressure produced by a single motor ejection charge. As the others will come later but will not help much is putting out the laundry.

John, I may be taking to much advantage of your expertise here, but what the heck.

What is the largest volume (say tube diameter) a MMX can reliably blow open? Could you mount an MMX motor in a BT20 say 4" long with wadding, streamer, and nose cone?

Depending on the design of your booster it may be possible and simpler to trim it out as a backslider. Or if you have enough room, use one of the new generation of 1S Lipo powered ultra small deployment altimeters to do its job, which could include both firing the upper stage and deploying the booster recovery.

BABAR said:

John, I may be taking to much advantage of your expertise here, but what the heck.

What is the largest volume (say tube diameter) a MMX can reliably blow open? Could you mount an MMX motor in a BT20 say 4" long with wadding, streamer, and nose cone?

Click to expand...

I'm not sure what the Maximum can be, I have in the past used a single MMX-II motor in 1/8A PD on an all vellum model that tapered from BT-20 down to T-2+ over 10" long Deploying an 18" 1/4mil mylar chute perfectly every time but would not quite kick out a 22" 1/4mil mylar chute. Successfully flown many 1/8A-SD models BT-5 x 8" long with 2 x 40" accordion folded 1/2mil mylar streamers.

I've also used a single MMX-II motor to eject a small streamer from a 34" long full length T2+ body in my ELE-1 (extreme Length Experiment) 103" long Micro Maxx powered "SuperRoc" which does Back slide-Glide very well.

To be sure most of the time I use that large an OD Air-frame for a Micro Model it is generally a Cluster of 3, 4 or more micro motors However as mentioned above in my previous post They ALL deploy the recovery system with the power of the first ejection to go off.