Dove head first into Aerotech rockets and Quest composite motors, should I have?

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wsnider

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I recently returned to rocketry in the Winter and bought and built alot of Estes models both new and from way back. Took dad out and launched maybe 20 times. Everything went perfect. So I decided to step it up and get about $500 worth of Aerotech gear. Specifically a Strong Arm and a Quad Runner, with a box full of about every Q Jet motor.
First off, I'm not here to bash Aerotech as it's only my first experience with them. But I've had nothing but issues with my experience.

The Strong Arm body was to big in diameter to clip everything in as designed it misshaped the tube into a rounded square. One fin would never clip in. The motor tube had to have a layer peeled off then sanded just to get the locking rings on it. Also, one of the strakes is mismoulded and bent. The Quad Runner was missing one of the balsa fin sheets. No big deal, I just copied the one it had. I don't consider any rocket building particularly hard at this level since I've built many balsa and composite planes and kits. So I'd say I have a good building background of about 40 years. I did a lot of fitment and checking to give the Strong Arm rocket every chance to be built.
I reached out to Aerotech and they sent me a second body and motor tube. Bonus points to them for helping me out with my issue. The strake I guess I'll have to see if I can heat and reshape it myself. So I'll be back building it soon.

The other issue is with the motors. Dad and I had another mostly Estes launch, all great again. Even fired off our first E engine....nice. So I tried 2 18mm D Q-Jets in a small Estes Wizard since its a small investment for testing. The first one sputtered around n the pad then lifted off spiralling around to 30 feet away. The nozzle was melted to the side on inspection and it never really lit solidly. No biggie, lets try the other engine. Worse. It sputtered off the pad 5 feet high, stalled then kind of relit in a pulsating sound as the rocket flew away at about a 20 degree angle. Buh bye! Literally over the river and through the woods. So now I'm afraid to use the $300 worth of motors since my failure rate with Quest motors is sitting at 100%. As far as I can tell Im getting the ignitor to the top and using the plastic pic to hold it correctly. So I don't think its user error. I don't expect every motor to be perfect. But whats a normal failure percentage with these? Is it normally 1 in 20? More? Less? Did I pick the motor that does this the most? Am I just unlucky with Aerotech products? I spend a lot of time on some of my bigger better or classic builds. I don't want to risk them needlessly on composite motors if the chance of failure due to motors is 50/50.
Anyone have a good amount of experience with the Q-Jet motors? Thanks in advance for any advice.
 
With Q-Jets, the date code is everything. Save your casings - well except for the "over the river and through the woods" one - and contact Aerotech Customer service. I had a couple of "chuffers" and it turns out that pack was from an early batch that had bad nozzles. They are VERY good about supplying replacements.

Here's a couple of pictures that I sent them showing the two chuffers and a successful motor. The date codes are clearly visible, starting with 05--- or 01---

20231120_191346.jpg
1717522853973.png


So welcome back to the madness! Sorry about your bad experience, but I have flown Q-Jets successfully. They are great for heavier 18mm rockets like Estes's Venus Probe. Note that Estes's E12's have a bad reputation as well, though not in my limited experience.
 
You weren't getting that wizard back if the D Q-jet had worked properly, lol.

I've had nothing but trouble getting the 18mm White lightning Q-jets to start, so I wouldn't recommend those to anyone. I haven't had issues with the Black Max nor the 24mm ones, though.

Estee BP will be much easier to cluster in the Quad Runner. I guess there may be a couple of Q-jets that the Strong Arm will fly on, but I've not gone lower than a mid F in mine.
 
You weren't getting that wizard back if the D Q-jet had worked properly, lol.

I've had nothing but trouble getting the 18mm White lightning Q-jets to start, so I wouldn't recommend those to anyone. I haven't had issues with the Black Max nor the 24mm ones, though.

Estee BP will be much easier to cluster in the Quad Runner. I guess there may be a couple of Q-jets that the Strong Arm will fly on, but I've not gone lower than a mid F in mine.
FWIW, I’ve clustered the Quad Runner on D16 Q-Jets, using the supplied igniters. It was a great flight, except for the part where it drifted far into tall prairie grass, never to be seen again.
 
FWIW, I’ve clustered the Quad Runner on D16 Q-Jets, using the supplied igniters. It was a great flight, except for the part where it drifted far into tall prairie grass, never to be seen again.
I've never clustered them, but those are Black Max. I bet that looked cool!
 
Thx all.....So if I have some of those date codes. Should I fire them or just send them back before risking it? Do they take them back before a possible failure?
 
@wsnider ... you said your new to Quest Q-Jets, so I'm going to note a simple thing to check... unlike Estes Black Powder were the igniter sits just inside the nozzle; with Q-Jets the igniter needs to pass all the way to the top of the motor. There is a slot in the propellant grain. GENTLY poke around till you "find" the slot then push igniter all the way up.


If you are not at the top of the fuel grain, it will not burn correctly at all.
 
The Strong Arm is fun but needed to sand the plastic fins to get them to fit. It veers a bit so probably needs a bit of NC weight. I turned mine into a payload. I plan to try a G74 next time.



I've lost too many rockets on chuffing Qjets so I avoid them now. There's only so many motors that Karl can send me.
 
Not to jinx myself, but.....

Every Qjet I have used ( on second 24 pack has worked) one did have I believe a nozzle failure. A rocket that had always flown straight and true, about 20' off the rod, turned and blasted sideways like a harpoon missle never to be seen again.

I really like the black smoke!
 
Qjets have had issues. See these threads:

https://www.rocketryforum.com/threa...q-jets-c18-and-d20-looking-for-advice.167338/
https://www.rocketryforum.com/threads/q-jet-follies.182433/

However, I haven't seen any complaints about the E35 or F41 motors.

The Estes 24mm D12 and E12 have had lots of complaints lately. Many threads.

Often these are just bad batches. But sometimes the issues seem to be endemic, such as my issues with the Qjet E26 motors. But others have reported no issues. So perhaps the problem is age, storage, or handling. Humidity seems to be bad for White Lightening. Temperature extremes and rough handling are not good for black powder.
 
I've had mostly good luck with the C12s and D16s. I did have one D16 flight where the rocket took a strange turn off the rod but straightened out pretty well and had a good flight. In hindsight, I probably blame the motor, but everything turned out OK. I have had no significant ignition or chuffing issues.

I am however concerned about some D22s and E26s I bought but haven't flown yet. I feel like there were some nozzle issues early on, haven't looked at my date codes or even really know what the deal is there. If I can convince myself that mine are probably OK I may try them at LDRS.
 
For some reason, I keep trying Qjets. Mostly because some of the motors fill a hole in the total impulse spectrum. For example, the 18mm D Qjets are between regular Cs and Ds. And the E26 is the only mid E on the market if you have an aversion to the Estes E12 - which I do at this point. So I keep trying them.

After receiving numerous warranty replacements (C18, D16, D20, D22), I think they may have a handle on the problems. Date codes in 2023 have been 100% reliable for me. And an unscientific fingernail scratch test of the nozzles seem to reveal that they are harder than in the past.

As for chuffing - I "juice up" the igniters. A dip in ProCast followed by clear fingernail polish seems to do the job. Don't overdo this, however. A friend tried sprinkling black powder on an igniter that had wet fingernail polish and it blew out the side of a B6 Qjet. ProCast is slower burning.

What may still be an issue is how well the White Lightning motors age. Time will tell.....

Hans.

Edit: As others have mentioned, the BlackJack motors are easier to light. The warranty replacements I received for them were because of asymmetrical nozzle issues causing the rocket to "skywrite".
 
Thx all.....So if I have some of those date codes. Should I fire them or just send them back before risking it? Do they take them back before a possible failure?
They don't take them back. If your date codes match a problematic batch number, they simply send replacements and you dispose of the unburned bad ones; either burn them on the ground or soak them. I recently had a D20 CATO (Catastrophic takeoff; actually, the case over-pressurized and cracked both it and the plastic motor mount of the Estes Power Patrol it was in. I sent them the date code and Karl asked that I burn the remaining 3 on the ground and send him the results. I take it from his response that my date code does not have any, or only a very few, problem reports. He also said he'd send replacements from current production. They're very good about it, but a ruined rocket is a stiff price to pay for me; I barely have enough time to build as it is. However, I should add, I've not actually had a rocket ruined by a Q-Jet yet; all damage has been repairable.
 
One other thing that I've noticed... Think about "Rod Whip" .. it can not be ruled out for some squirrelly flights.

A "large diameter" and "heavy" Estes rocket that has an 18mm (maybe 24mm) motor mount, may only have an 1/8 lauch lug. Think Citation Patriot, or similar.

If flown on Estes Black Powder motors it takes all the rod length you can get (I have 4-6ft) to get up to a stable speed. The offset distance from Thrust to Rod doesn't flex the rod a large amount because of low thrust/acceleration.

That same rocket on a composite motor, gets quite a "kick", and will have more flex to the Rod from the higher thrust. So shortening the rod helps.... BUT AND IT'S A BIG ONE, IF the motor "chuffs" significantly on ignition, the flight can be worse due to slow speed off the rod... So going to a shorter rod, IS a double edged sword.

My current setup for Quest 18mm C & D , shorter rod, enhanced starters, newer motors, stored in sealed containers WITH desiccant. YMMV
 
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So these are my D22s, apparently from 2021... I guess I shouldn't chance these? Bummer if true, but I'd rather not blow up a rocket.

View attachment 649068
Might be a little scary. There was an Aug 2021 date code on E26s that had a near 100% failure rate, enough so that a couple of local clubs banned them. I had 4 of them blow before I gave up on them.

Then I had some 2022 D22s that didn't Cato, but they had "sideways" thrust. But my 2023s have performed well.

Hans.
 
Ron yes...exactly light that for the chuffing one. The other one was half chuffing and just spiraling around. The nozzle on that one was but at a steep angle on inspection.
 
So these are my D22s, apparently from 2021... I guess I shouldn't chance these? Bummer if true, but I'd rather not blow up a rocket.

View attachment 649068
You might inquire of Aerotech if that's a date code they'll send replacements for. And you might have done that in person at LDRS, if only someone had thought of it. But it's not to late to do it anyhow.
 
You might inquire of Aerotech if that's a date code they'll send replacements for. And you might have done that in person at LDRS, if only someone had thought of it. But it's not to late to do it anyhow.
I did send a direct inquiry to Aerotech and they said if the nozzles look OK then they should be OK. Not sure I trust that answer.

I actually saw Gary Rosenfield walk by at LDRS but I didn't think it appropriate to bug him about that at the time.
 
Quite frankly (Fredly?) I would like to give up on Qjets altogether. The problem is that they are the only game in town for certain impulse /thrust levels. Like a C18, for example. Or a baby "E", the E26. I'm substituting RMS D15 for the Qjet D22, it's a great alternative.

Hans.
 
I did send a direct inquiry to Aerotech and they said if the nozzles look OK then they should be OK. Not sure I trust that answer.

I actually saw Gary Rosenfield walk by at LDRS but I didn't think it appropriate to bug him about that at the time.
I talked to Karl and Gary last year at XPRS. Karl called me his beta tester of the 18mm motors. I’m not sure how I feel about that.

If the 18mm motors are before 2022 and have the light grey clay, they’re suspect but work perfectly fine in a Vortico or similar rocket.

Unfortunately they have to fail before Karl is willing to mail you replacements. At least in my experience…
 

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