ECONO MAX SU F44 MOTORS

Hi everyone, I have had good success flying this motor in single motor rockets.
However yesterday I had failures in two cluster applications. First I attempted a two cluster and only one motor I lit. It was a safe flight with no damage incured albeit a low flight. Then attempted a three motor cluster, only one lit and with an eight second delay it came in hot and ejected the chute 100 foot above ground breaking a fin and zippering the tube. Not ok.
These were the ignighters supplied with the motors but dipped in Quick Dip. The other ignighters I have dipped have worked in single motor applications. I'm thinking the first motor lit ripping the other ignighter (s) from their motors before they had a chance. The former president of our club told me they ( F44's) are hard to light.
So I'm rebuilding my Maxi Force again. I dont know what to use in clusters of 24mm motors. I pulled three Estes E12's out, cause of fear and installed the F44's.
Any advice out there on what may have happened and what 24mm motors to use in clusters?
Thanks very much!
John

Composite motors are difficult to light simultaneously. And when they light they quickly shoot off the pad from the higher thrust compared to BP motors. Which means if one fires a split second early it could pull the igniters out of the others.
Notice that in single motor firings of composites, sometimes the motor lights right away, and sometimes it takes a second or two? And sometimes the motor chuffs, then lights?
I would stick with BP motors for clusters for now. You could rig up electronic on board ignition for your composites, but that would be complicated and expensive.
Laters.
PS No need to dip the igniters that come with composite motors. They already have a pyrogen at the tip. Dipping is for the new Estes igniters with the white coating for use in BP motors.

Thank you sir! I figured that's what happened. Last time I flew the two motor cluster rocket I did manage to light both F44's at the same time so I developed a false sense of security. I will use the Estes E12's I originally pulled due to fear of having a Cato. I misjudged the choice. Live and learn. By the way I found out an Estes Star Orbiter flies great on a F44!
Thank you as always!!
John

Are you twisting your ignitors together in series or parallel ?

3stoogesrocketry said:

Are you twisting your ignitors together in series or parallel ?

Click to expand...

Always parallel.

F44 is White Lightning, which is one of the more difficult AT propellants to light, which doesn’t help.....

I’ll bet the Star Orbiter scoots really well on that motor.

Yes it took off like a bolt of lighting! Screamed for 1.5 seconds then coasted to about 1800 ft. Too bad it drifted around a mile over two creeks and a barbed wire fence. But I recovered it! "Hot Fun In The Summer time"

What's the biggest motor anybody has flown the Star Orbiter and recovered it whole without electronics?
So far the biggest motor I've flown on it was a 55NS F21. Went out of sight, finally saw the florescent pink chute. It drifted over a mile into the next door ranch over a barbed wire fence. With help it was recovered.

Best igniters for lighting an AP cluster are either the Quickburst igniters or ematches dipped in a hot-burning pyrogen. If you're a DIY'er, check out the pyrogens that Firefox sells.

These things are crap to ignite. I often go through 2-3 first fire's getting them to go. Bigger ignitors (the ones I like for HP) won't fit in the nozzle. The propellant is super white lightning, a different formula than regular white lightning, but also even MORE prone to absorb moisture and oxidize. Best thing to do is scrape the slot with a small file prior to igniting. Blue dip also helps. I love the motors (I do have a "few") but hate them for the reason you state above. The G74's I can fit the "Good" ignitors into, so those aren't as big a problem...

Thanks for that info.....yeah I had several single motor flights and one successful 2 motor cluster flight and thought
" YEAH, THATS THE TICKET!!"
Did not know they were so hard to light. Live and learn.
Great thing about this obsession, learning something new every day.

swatkat said:

These things are crap to ignite. I often go through 2-3 first fire's getting them to go. Bigger ignitors (the ones I like for HP) won't fit in the nozzle. The propellant is super white lightning, a different formula than regular white lightning, but also even MORE prone to absorb moisture and oxidize. Best thing to do is scrape the slot with a small file prior to igniting. Blue dip also helps. I love the motors (I do have a "few") but hate them for the reason you state above. The G74's I can fit the "Good" ignitors into, so those aren't as big a problem...

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I had even enhanced the effect with a little dip in the Quick Dip jar. Just enough to add additional fire and still be able to insert them into the motors.

Yeah, I add a sliver of Blue thunder...

Funny... i have been using this motor exclusively in a 2-motor cluster configuration and have only one instance where a motor failed to light out of five or six flights - still not a huge sample size, but indicative. No, i do not dip or otherwise modify the stock igniters.

I think there is definitely some good ideas and info here, but you should also make certain that your launch system is capable off delivering excessive amps (not just “sufficient”) to fire both igniters essentially instantaneously. I think a lot of issues can be ameliorated with MORE POWER!!! That is the rocketeers motto, right?

It was at a club launch with a system capable of delivering 12 v and 30 amps. Wired in parallel, cleaned the clips, still no joy.
No more F44 clusters for me.
In my modded Estes Impulse I think I will try two F39T reloads.

Were the igniters bridgewire based or did they use a conductive pyrogen? The later can have a wide variance in resistance. This causes a significant variation in power delivered and ignition (of the pyrogen) times.

Best practice is to measure igniter resistance and match them closely. You need to be careful with what you use to measure resistance. It should use a safe test current and be capable of measuring low resistances. (The pros use something like the Valhalla 4314A.)

I saw the flight as I was headed out to retrieve my flight. I heard all three igniters fire. Seems like two were pulled out when one lit fast. This is why I secure cluster igniters to the motors and carry extension leads to allow the model to take off with leads attached. I have only flown black powder clusters.

Chas

The F44 motor is different from standard white lightning, if I recall, AT referred to them as fast white. They *do* start faster than WL, though not as fast as BT. Maybe try a clip whip, with sufficient slack on each pair, to minimize chance of one starter getting pulled out early?

When I need more thrust for my 24mm clusters, I use CTI E22 or E31. I’ve mixed these with D12 motors a few times, so far complete success. Always started with a 12v relay system.

Thanks for the advice! I believe y'all are correct using extended leads for the clusters. I presume it has seperate leads for each motor instead of twisting the wires together. Do y'all make them yourselves or are the purchased?
Thanks again
John

swatkat said:

Yeah, I add a sliver of Blue thunder...

Click to expand...

I want to hear more. I have used that method when putting together RMS motors, but have you been able to do it with SU motors with a narrow nozzle opening?
Thanks

John - I normally have clip whips and extension leads at the DARS launches. Since Dyer and I were down the line from you, we were unaware of your cluster flight. Don't hesitate to borrow stuff.

John Taylor said:

I want to hear more. I have used that method when putting together RMS motors, but have you been able to do it with SU motors with a narrow nozzle opening?
Thanks

Click to expand...

Yup, just a little shaving before the ignitor.

Buzzard said:

John - I normally have clip whips and extension leads at the DARS launches. Since Dyer and I were down the line from you, we were unaware of your cluster flight. Don't hesitate to borrow stuff.

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Thank you sir! Rocket people are the nicest people around.
Perhaps I could take a look at your leads and make my own. Really appreciate your kindnesses!
See ya at the next launch!
John

swatkat said:

Yup, just a little shaving before the ignitor.

Click to expand...

Thanks I will do that next time, I just happen to have part of a BT slug rattling around in my range box. Thanks again!
John

Yeah, mine was from a swelled E28 grain someone was going to discard. It's been a gift that keeps giving!

Update, Ok so I got a cluster whip and used E30 BT motors. Lit a two motor and a three motor cluster without any problems. I just used first fire igniters with a little extra pyrogen. I believe the whip helped but the main improvement came from the Blue Thunder propellant.

https://youtu.be/BH3cM1ERzOI?t=169 Watch the slow-mo

I got 3 F67's to light on a Loc Magnum. I used Wildman ignitors and left them as long as I could. It took nearly all the rod before the last one lit.

Another vote for Aerotech Blue Thunder. I've done clusters of F39T with 100% success. I haven't tried any of the 24mm CTI yet, but the Pro38 motors with the ignition pellet are great in clusters/airstarts.
-Ken