Staging MicroMaxx

[Antares JS]

So, I've tried flying my Fliskits Doubles twice now and both times, the sustainer failed to ignite and the rocket lawn darted. I am using an NE motor in the booster and taping the motors together per the instructions. I've seen other threads swearing this works, but with two failures now I'm starting to wonder if I should sprinkle a few grains of BP down the forward end of the booster or use a wire to dab a tiny bit of quickdip in the nozzle of the sustainer.

I'd like to hear about other people's experiences staging Micromaxx motors and see if there's anything I can do to make this a bit more reliable.

 

[GlenP]

I have not tried to stage MMX, but when I have had an ignition failure with a 13 or 18 mm motor, to help ensure proper ignition next time, just single stage, I will take the smallest drill bit in my set and lightly spin it with my fingers to expose new black powder in the nozzle, in case there was some charred material left over from the ignition that misfired. Not sure if you can find a drill bit small enough to lightly scratch the surface of the powder in a MMX nozzle, or if that technique is considered an engine modification and against NAR safety code. Maybe that might help a sustainer to light as well?

 

[kuririn]

I've launched the Doubles twice, both times the sustainer motor ignited.
Glen's suggestion about scuffing up the BP couldn't hurt.
The nozzle is so small you would probably have to use a needle or pin.
An ice pick is too wide.
The booster motors' delay is disconcerting. The first time the sustainer backslid before igniting and the second stage wound up going near horizontal. Second launch was better.
Good luck.

 

[Antares JS]

Hopefully third time's the charm. I'm planning to fly the Doubles again at the MDRA launch this weekend and try GlenP's suggestion of scraping the inside of the sustainer motor a bit.

 

[kitbasher99]

Please let us know how it goes. We here at Semroc have an Omega kit we would like to release but we can't get the sustainer to light either. Makes it hard to sell if it won't work right.

 

[kuririn]

Maybe a static test with just the motors taped together and clamped?
Easy to set up and no chance of damaging the rocket.
See if the NE motor lights the sustainer.
If not, maybe defective motor batch?

 

[Ulexis]

Please let us know how it goes. We here at Semroc have an Omega kit we would like to release but we can't get the sustainer to light either. Makes it hard to sell if it won't work right.

Dang, I need that Omega.

 

[Antares JS]

No joy, failed again. On a related note, Doubles has now survived three lawn darts into wet sod. That has to be some kind of record.

I guess it's possible I have a defective batch of NE motors, but the sustainer motors come from a 24-pack of regular MMX II motors that have had many other successful flights.
actual booster motor would be sending burning BP forward.

I think I'm going to take Kuririn's suggestion of doing a static test to try a few more drastic ideas before trying it in the actual rocket. My first idea is to sprinkle a TINY pinch of BP (like, a few grains) down into the forward end of the booster. My best guess is that the delay is not moving enough hot gas forward to start the sustainer. Since an actual booster motor would be sending burning BP forward, I'm hoping this might help.

 

[kuririn]

AntaresJS,
Revisiting this thread, after thinking about it it seems more than coincidence that both you and kitbasher are having problems with the NE motor.
My batch was purchased a few years ago. Perhaps there is some small difference between my batch and the newer NE batches? Would you like to try a few NE motors from my batch and see if that makes a difference?
No charge, I have plenty.
EDIT: I just remembered, shipping rocket motors requires special regulations. Will have to check with the PO about these smaller motors. Don't know if they can go by air.

 

[Antares JS]

AntaresJS,
Revisiting this thread, after thinking about it it seems more than coincidence that both you and kitbasher are having problems with the NE motor.
My batch was purchased a few years ago. Perhaps there is some small difference between my batch and the newer NE batches? Would you like to try a few NE motors from my batch and see if that makes a difference?
No charge, I have plenty.
EDIT: I just remembered, shipping rocket motors requires special regulations. Will have to check with the PO about these smaller motors. Don't know if they can go by air.

If you're able to ship them, I'm interested. Keep me posted if you're able to find out.

 

[kuririn]

After doing some research it appears the shipper must obtain a Letter of Authorization from the USPS Manager of Mail Preparations and Standards in Washington DC, 30 - 60 days for approval.
Then even MMX motors must be shipped by surface mail, air shipment not allowed which means a slow boat from Hawaii to the West Coast.
Not worth it in my opinion.
I will, however do a static test and report here in a few days.

 

[Antares JS]

Agreed, not worth it. Thanks for offering though. Keep us apprised of your tests.

 

[Antares JS]

Success today!

I ended up using an x-acto knife and a sharp piece of wire to scrape out the delay element from the booster, to the best of my ability to tell. I flew the Doubles and finally got ignition of the sustainer. The only annoying thing was that I must have used too much tape because the booster airframe did not separate and got scorched on the inside.

Quest probably really just need to remove the delay element from the booster motors.

 

[caveduck]

There was some recent and very nice NARAM R&D work showing that it's plasma from the booster propellant that ignites upper stages, not burning granules. That would create a low expectation that slow burning delay material would work very well at all for upper stage ignition. But it might have to be there for the manufacturing process of such a small motor to work. I doubt it's there by accident. Very interesting question here.

 

[Antares JS]

There was some recent and very nice NARAM R&D work showing that it's plasma from the booster propellant that ignites upper stages, not burning granules. That would create a low expectation that slow burning delay material would work very well at all for upper stage ignition. But it might have to be there for the manufacturing process of such a small motor to work. I doubt it's there by accident. Very interesting question here.

I remember seeing a story that they had the idea to make booster motors after a bunch were already made, and all they could do was take the ejection charges out. I don't know if that's true though.

 

[shockie]

scrape it out as mentioned and add just a dab of 4f bp...... a dab being just a few grains

I remember seeing a story that they had the idea to make booster motors after a bunch were already made, and all they could do was take the ejection charges out. I don't know if that's true though.

I thought I was once told that for about 5 seconds Estes produced booster motors with either a thin clay cap or a paper cap, as they didn't want kids messing around with the exposed BP propellant grain in booster motors.....then they started getting reports that the booster wasn't igniting the upper stages so they went back to the way they are.... I may be mis-remembering some or all of this.....

anyway, I've removed both the ejection charge and delay trains....I used a water dropper and used 1 drop at a time to slowly dissolve the delay train.....i just kinda scraped the BP particles out.....

 

[kuririn]

Flew the Fliskits Doubles again today.


Both motors ignited but the booster stage didn't separate from the sustainer for some reason.
So it got a little toasted on the inside.
I think I will have to friction fit the booster motor a little snugger.
Anyhoo, here's the video:

 

[Antares JS]

Flew the Fliskits Doubles again today.
View attachment 493786

Both motors ignited but the booster stage didn't separate from the sustainer for some reason.
So it got a little toasted on the inside.
I think I will have to friction fit the booster motor a little snugger.
Anyhoo, here's the video:

Same thing happened to me when I finally got my upper stage to light. Haven't gotten around to trying it again yet though.

 

[BABAR]

Success today!

I ended up using an x-acto knife and a sharp piece of wire to scrape out the delay element from the booster, to the best of my ability to tell. I flew the Doubles and finally got ignition of the sustainer. The only annoying thing was that I must have used too much tape because the booster airframe did not separate and got scorched on the inside.

Quest probably really just need to remove the delay element from the booster motors.

Very late to the party, but something is rotten in Denmark here. Boosters shouldn't have any CAP or DELAY to scrape out, they should be just a nozzle and propellant. I haven't done MicroMaxx in some years, but I know all my 18mm and 24 mm boosters, when you look at them from the forward end, you see BLACK powder staring at you, as opposed to non-booster motors which have the grey cap.

I think there is more than one reason you can't (or at least should NEVER) use a standard motor with ANY delay, no matter how short, as a booster motor.

The first reason is that you don't WANT any delay with BP staging. It's different with electronics, there you may have tilt or altitude locks so sustainer won't (or is less likely to) light if it is in unsafe position (hopefully.) With BP motors, the motors don't care which way the rocket is pointed or how high it is, they will (usually) stage regardless.) Having no delay doesn't PREVENT off axis staging, but the SOONER the rocket stages, the less time it has to get OFF axis. So staging with black powder is less efficient than electronics. Fine with me, I like to SEE the staging and FIND the booster, so I am more than happy to have staging occur as long as the rocket has left the rod (I had one stage on the rod once, it was.....interesting.)

But there is another reason. Standard motors when the ejection charge goes off blow chunks, chunks of clay cap and propellant. These chunks, even if propellant, or not likely to ignite a booster since they have to get through the narrow nozzle. Despite Stine's book, it has been shown that black powder BOOSTERS ignite the sustainer by radiant heat from the hot gas coming up from the sustainer, and this is best achieved with pure black powder with no cap or anything in between.

I'm also not convinced the tape is needed even for non-gap staging, the motors are so darn close that the gas should bet there before the pressure blows the sustainer off. WITH a gap you definitely need well placed vent holes to prevent premature separation prior to ignition. I've done 13 mm non gap staging with no tape and no vents and it worked fine. Might reduce the issue of POSITIVE sustainer ignition WITHOUT separation, which as you guys have noted tends to toast the sustainer.

So I am curious, Gary, did your MicroMaxx boosters have any sort of cap?

 

[kuririn]

So I am curious, Gary, did your MicroMaxx boosters have any sort of cap?

Booster motors don't have a cap, regular motors have a clay cap.
They are designated NE (no ejection) but my understanding is that they DO have a delay.

 

[Grog6]

The first time I tried staging, circa 1970, it went up, flipped over, Then the sustainer lit, lol.
Landed in the middle of the highway, full speed. Largest remaining piece was attached to the 'chute mount.

 

[BABAR]

Booster motors don't have a cap, regular motors have a clay cap.
They are designated NE (no ejection) but my understanding is that they DO have a delay.

interesting.

took a while to find it, but as usual you are right

http://nar.org/SandT/pdf/Quest/MicromaxxII.pdf
key quote

“The "NE" motor has 1 second of tracking smoke but no ejection charge.”

by all I understand of BP staging putting in a delay is a bad thing, as it gives the rocket more time to go off kilter.

the QUEST web site states the following for the STANDARD MOTOR
https://www.questaerospace.com/MicroMaxx_Motor_Pack_6_piece/p4193205_16428940.aspx
“They have a three quarter second burn time followed by a half second delay, then ejection.”

am I the only one that thinks it is really weird to put in a 1 second delay on the BOOSTER with only a 1/2 second delay on a full motor?

also question with the delay burn through provides as much hot radiant gas as pure black powder propellant.

the Estes boosts have nothing but a nozzle and propellant in Their boosters

Example

https://estesrockets.com/product/001565-d12-0-engines/
may have to hit the ”technical specifications “ tab

key quote

”

Time Delay	None”

Looking at the NAR thrust curve, seems to me the additional delay was a bad idea. The less time for fecal turbine interaction, the better, IMO.

also interesting, I could only find the NE motors on the JonRocket site, didn’t see it on Quest web page. Probably just missed it.

 

[Antares JS]

am I the only one that thinks it is really weird to put in a 1 second delay on the BOOSTER with only a 1/2 second delay on a full motor?

See post 15 on this thread. The booster motors may not have originally been intended to be booster motors.

 

[kuririn]

I could only find the NE motors on the JonRocket site, didn’t see it on Quest web page.

Erockets has some.
Quest Motor Micro Maxx No Ejection(NE) & MMX-G2 Igniter/Starters (6pk) 5665 ** <Required to Pay for Parcel Select Shipping> (erockets.biz)
Quest has them but they don't list it on their web pages. I ordered mine a few years ago from their customer service dept.
Still waiting for the Semroc MX Omega. I might have to scratch build one.

 

[Alan15578]

scrape it out as mentioned and add just a dab of 4f bp...... a dab being just a few grains

I thought I was once told that for about 5 seconds Estes produced booster motors with either a thin clay cap or a paper cap, as they didn't want kids messing around with the exposed BP propellant grain in booster motors.....then they started getting reports that the booster wasn't igniting the upper stages so they went back to the way they are.... I may be mis-remembering some or all of this.....

anyway, I've removed both the ejection charge and delay trains....I used a water dropper and used 1 drop at a time to slowly dissolve the delay train.....i just kinda scraped the BP particles out.....

I have not heard that about Estes booster motors.

I think the MM NE motor was intended to be "plugged" motor for saucers and such, and not as a booster motor.

I would advise against your motor modification procedure. except as a purely experimental procedure to help you understand the how and why of MM NE motors. Just adding a dab of 4f BP would help, but then you may be better off just using a standard MM motor...

 

[cwbullet]

I have never seen this done. Interesting and I might have tiny it.

 

[tjkopena]

I did ask Jennifer @ Quest Customer Service about MMX NE motors in late August. They are not on the dealer price list, in addition to not being on the website. She said they were not available, but in such a way that I could believe there might still be some remnants hidden in some dark corner of the warehouse. Not enough to keep in the usual course of business though. Wouldn't shock me if a better known customer or a higher-tier dealer might be able to get a different answer, maybe by first talking to someone more directly placed in the warehouse side of the business. Total speculation though.

 

[Alan15578]

Very late to the party, but something is rotten in Denmark here. Boosters shouldn't have any CAP or DELAY to scrape out, they should be just a nozzle and propellant. I haven't done MicroMaxx in some years, but I know all my 18mm and 24 mm boosters, when you look at them from the forward end, you see BLACK powder staring at you, as opposed to non-booster motors which have the grey cap.

I think there is more than one reason you can't (or at least should NEVER) use a standard motor with ANY delay, no matter how short, as a booster motor.

The first reason is that you don't WANT any delay with BP staging. It's different with electronics, there you may have tilt or altitude locks so sustainer won't (or is less likely to) light if it is in unsafe position (hopefully.) With BP motors, the motors don't care which way the rocket is pointed or how high it is, they will (usually) stage regardless.) Having no delay doesn't PREVENT off axis staging, but the SOONER the rocket stages, the less time it has to get OFF axis. So staging with black powder is less efficient than electronics. Fine with me, I like to SEE the staging and FIND the booster, so I am more than happy to have staging occur as long as the rocket has left the rod (I had one stage on the rod once, it was.....interesting.)

But there is another reason. Standard motors when the ejection charge goes off blow chunks, chunks of clay cap and propellant. These chunks, even if propellant, or not likely to ignite a booster since they have to get through the narrow nozzle. Despite Stine's book, it has been shown that black powder BOOSTERS ignite the sustainer by radiant heat from the hot gas coming up from the sustainer, and this is best achieved with pure black powder with no cap or anything in between.

I'm also not convinced the tape is needed even for non-gap staging, the motors are so darn close that the gas should bet there before the pressure blows the sustainer off. WITH a gap you definitely need well placed vent holes to prevent premature separation prior to ignition. I've done 13 mm non gap staging with no tape and no vents and it worked fine. Might reduce the issue of POSITIVE sustainer ignition WITHOUT separation, which as you guys have noted tends to toast the sustainer.

So I am curious, Gary, did your MicroMaxx boosters have any sort of cap?

You seem to be approaching this from an HPR perspective. My perspective is that of a dead horse MR competitor. I will admit that I have little experience with MM motors and rockets. I did pop a few of them in the back yard, but I did not find them satisfying or fun. I have not seen the NE variant. When they first came out, I thought the delay was too short, and that the best contest use might be as a "trimmer" motor to boost delivered total impulse up closer to the class limits, or perhaps for Superroc or R/G. Even the MM II had the too short delay. Still, I am interested in the creative effective uses of MM motors , such as staging.

First, the Estes A10-0 is a nice motor. It has a thrust spike followed by about .8 seconds of very low thrust "delay". This delay is useful as a booster. I also used it effectively at NARAM-22 (groan) to fly a 21 foot 4.0 Oz, superroc. It was controversially DQ'd for using a booster motor, I would have happily clustered MM motors, if they had been available back then. The A10 is also available as a plugged motor.

In general, our rocket motors have too high a thrust for maximum altitude performance. There is wealth of information in the MR literature on using delayed staging to increase altitude. Of course you have to run the numbers and understand what you are doing. Using electronics or fusing to effect delayed staging is often too heavy or complex, but sometimes a short motor delay is just about right, and staging tip off is not an issue. I recall another NARAM where D altitude was flown. An 18mm composite D was the best choice, but they are expensive, finicky, and they had no tracking delay smoke. Of course the rule of day was that you could make any number of flight attempts until you got a closed track. Staging a Centuri C5-3 to an Estes C6-7 was the next best option, and it clearly out performed the C6-0 booster in similar models. Now any staging will have lower reliability than a single stage flight. but the question is will reliability be high enough for contest use? The number of observed flights was very low and demonstrated staging reliability may be as low as 50 percent, but with two official flights allowed, that is a 75 percent chance of success. Actually, after a first flight staging failure. a second flight with with a C6-0 secured a lower place finish.

The direct staging reliability with an ejection charge is still an open question, but I think staging reliability from just a delay grain will be acceptably low. There is no MM booster motor, it is just a no ejection charge motor. Still, I am hopeful that someone can make work reliably.

 

[tjkopena]

I will admit that I have little experience with MM motors and rockets. I did pop a few of them in the back yard, but I did not find them satisfying or fun. I have not seen the NE variant. When they first came out, I thought the delay was too short, and that the best contest use might be as a "trimmer" motor to boost delivered total impulse up closer to the class limits, or perhaps for Superroc or R/G. Even the MM II had the too short delay. Still, I am interested in the creative effective uses of MM motors , such as staging.

The ejection delay is indeed way way too short for max altitude, at least for any traditional sport rocket build as opposed to heavier fun models or Quest's plastic rockets. But the flip side is that if they hit max altitude, in order to have any hope of getting them back you'd be a lot more constrained as to what size launch fields were required, how closely cut the grass/etc on that field need be, and what wind conditions would be viable.

 

[Alan15578]

I did ask Jennifer @ Quest Customer Service about MMX NE motors in late August. They are not on the dealer price list, in addition to not being on the website. She said they were not available, but in such a way that I could believe there might still be some remnants hidden in some dark corner of the warehouse. Not enough to keep in the usual course of business though. Wouldn't shock me if a better known customer or a higher-tier dealer might be able to get a different answer, maybe by first talking to someone more directly placed in the warehouse side of the business. Total speculation though.

My understanding was that there was never a stash of NE motors. Only standard short delay motors were ever manufactured. To fill demand for NE motors, standard motors were "remanufactured" by simply having the staff remove the ejection charge of existing motors by hand and repackaging them. If you order enough NE motors, they may magically appear, but there is no plan to produce any new MM motors.