Should serious (dangerous) chuffs be reported on M.E.S.S,?

[4regt4]

I know this has been discussed here before. In the past, it seemed like the consensus is that chuffs are not reported. But...

I've experienced (and witnessed others) chuffs where the rocket either climbs up to near the top of the rod, or clears it completely before thrust stops. Then it relights. As the rocket is near stationary at this point, when it refires, it can and does go off at severe angles. So far, I've not had one turn in the direction of the firing line.

I think these should be reported, as they are very dangerous.

Thoughts?

Hans.

 

[mikec]

It's not like it costs anything to report something to MESS, and it might help someone, so I say go ahead.

Most of the major chuffs I've seen have been motors that were old and stored improperly.

 

[4regt4]

I'm mostly having problems with the 18mm Qjets. D20, D16. It doesn't seem to correlate with the nozzle change in late 2021, as my most recent severe chuffs were D20s with date codes 100722-04 and 071422-01.

Hans.

 

[lakeroadster]

I know this has been discussed here before. In the past, it seemed like the consensus is that chuffs are not reported. But...

I've experienced (and witnessed others) chuffs where the rocket either climbs up to near the top of the rod, or clears it completely before thrust stops. Then it relights. As the rocket is near stationary at this point, when it refires, it can and does go off at severe angles. So far, I've not had one turn in the direction of the firing line.

I think these should be reported, as they are very dangerous.

Thoughts?

Hans.

I agree, they should be reported. The M.E.S.S. Report has a place for "Other Failure", you could input "Chuffing", then in the "Comments" perhaps you could describe the chuffing and then submit the report.

 

[jd2cylman]

As someone who got 16 stitches after an enthusiastic chuff pushed a rocket off a 6’ rod, it’s probably not a bad idea.

 

[4regt4]

As someone who got 16 stitches after an enthusiastic chuff pushed a rocket off a 6’ rod, it’s probably not a bad idea.

All I can say is "Wow".

Hans.

 

[Daddyisabar]

A chuff is partially the motors fault at best. Most of the blame usually goes to improper flier preparation and or igniter/launch system.

Ouch!

 

[rharshberger]

A chuff is partially the motors fault at best. Most of the blame usually goes to improper flier preparation and or igniter/launch system.

Ouch!

add in most of them are USUALLY older motors as was stated earlier. I can see chuffing being a concern in brand new motors but only if you can rule out improper ignitor installation and user error.

 

[CoyoteNumber2]

As someone who got 16 stitches after an enthusiastic chuff pushed a rocket off a 6’ rod, it’s probably not a bad idea.

Backstory please.

 

[4regt4]

A chuff is partially the motors fault at best. Most of the blame usually goes to improper flier preparation and or igniter/launch system.

Ouch!

Totally disagree. Easy for you to arm chair quarterback this, not being there! I've done around 200 launches in the last 2 1/2 years. Sorry, you are off base. Certainly some failures are rookie errors, but the large numbers of failures indicate a bigger problem.

Hans.

 

[rharshberger]

Totally disagree. Easy for you to arm chair quarterback this, not being there! I've done around 200 launches in the last 2 1/2 years. Sorry, you are off base. Certainly some failures are rookie errors, but the large numbers of failures indicate a bigger problem.

Hans.

In addition to doing that many personal launches in the same time period I have been the clubs main RSO and part of the launch operations team and chuffs are an extremely small percentage of motor failures, we actually see more catos than chuffs (in over 1500 flights per year, almost 700 every SodBlaster weekend). A s for the Qjets what launch controller is being used? We use either a Wilson F/X for MPR and up and either a 12v based wireless or 12v based wired system, and again dont see many Qjet chuffs ignitors burned yes, chuffs not many.

 

[Steve Shannon]

I know this has been discussed here before. In the past, it seemed like the consensus is that chuffs are not reported. But...

I've experienced (and witnessed others) chuffs where the rocket either climbs up to near the top of the rod, or clears it completely before thrust stops. Then it relights. As the rocket is near stationary at this point, when it refires, it can and does go off at severe angles. So far, I've not had one turn in the direction of the firing line.

I think these should be reported, as they are very dangerous.

Thoughts?

Hans.

Yes. Anything off normal, even if the flyer recognizes that they were at fault because even that can help us detect issues with directions.

 

[jd2cylman]

@CoyoteNumber2

Meh, old story. CTI 29mm G33 mellow in a Applewhite Stealth chuffed off the 6’ rod, landed on the ground then ignited.


The (long) after photo. I can post the immediate after the hospital ER pic, but it’s pretty ugly and gross.
And no, I don’t shave my legs….

 

[4regt4]

add in most of them are USUALLY older motors as was stated earlier. I can see chuffing being a concern in brand new motors but only if you can rule out improper ignitor installation and user error.

Qjets haven't been in production for a terribly long time. I consider a sort of break between the older and newer nozzle formulations, which occurred around the end of 2021. I'm actually having more problems with later motors. As for igniter installation, I don't know what to do other than what Aerotech is illustrating in this video:

https://www.rocketryforum.com/threads/qjet-igniter-retention.178850/post-2406919
And, FWIW, I take a very narrow wooden stick to find the depth of the Qjets, and mark that on the igniter to know if I've inserted far enough.

I'm dipping roughly 1/2 of the igniters in ProCast. The amount of ProCast is minuscule, as the nozzles on 18mm Qjets are quite small. Can't actually see a difference in chuffing, but definitely fewer ignition failures.

Hans.

 

[4regt4]

A chuff is partially the motors fault at best. Most of the blame usually goes to improper flier preparation and or igniter/launch system.

Ouch!

As I posted in another response, how much more "flier preparation" is needed over this:

https://www.rocketryforum.com/threads/qjet-igniter-retention.178850/post-2406919
Hans.

 

[smstachwick]

Totally disagree. Easy for you to arm chair quarterback this, not being there! I've done around 200 launches in the last 2 1/2 years. Sorry, you are off base. Certainly some failures are rookie errors, but the large numbers of failures indicate a bigger problem.

Hans.

A few months back I had a pair of D20s both continue chuffing throughout the burn. One got a Der Red Max up OK, high enough to lawn dart and crash. The other took my Ghost Chaser on a spiral trajectory where it looked like it might endanger a kid giving the low-power pads a wide berth as he headed for the mid-power pad. He was fine but the way the rocket was pointed was scary for a hot second. It wouldn’t surprise me to learn that he needed a change of clothes.

I laid off White Lightning motors of any kind until shaking down my L1 rocket.

 

[4regt4]

In addition to doing that many personal launches in the same time period I have been the clubs main RSO and part of the launch operations team and chuffs are an extremely small percentage of motor failures, we actually see more catos than chuffs (in over 1500 flights per year, almost 700 every SodBlaster weekend). A s for the Qjets what launch controller is being used? We use either a Wilson F/X for MPR and up and either a 12v based wireless or 12v based wired system, and again dont see many Qjet chuffs ignitors burned yes, chuffs not many.

Controller: Mostly an Estes Pro Series II with a 3s 11.7V Lipo. But also OROC's launch systems, which I believe are 12V.

Hans.

Edit: FWIW, I'm having no issues igniting Estes BP, Aerotech 24mm and 29mm reloads, nor AT single use like E20, E30, or F67. Nor 24mm D22 Qjets. Most of the composites give a puff of smoke, sometimes a couple of puffs, then take off. But the very light rockets utilizing the 18mm Qjets will lift off the pad on that initial "puff of smoke", often nearly (or completely) clearing the launch rod.

 

[Daddyisabar]

The Quest 18mm igniters and retention system just sucks. With my Awesome experience of 300 plus launches attended over the years, I can't get the darn things to light consistently either. Been there. Haven't chuffed one off the rod though.

Glad it's been clearly clarified it is just these motors with several well known issues. As an Awsome Monday morning quarterback wouldn't one make use a longer, quality rod/rail or even burn string to prevent fear of chuff off rod? Maybe don't use these particular motors on light rockets. Old AT 18mm reloads and single use motors are still around that might work better. Black powder 18mm motors?...never for an altitude junkie!

Could it be that dipping the stock igniters, giving them more "lifting" power is contributing to the problem? A powerful igniter can give good thrust by itself!

Not off base but out of the stadium with an inquisition/witch hunt on Quest 18mm motors and their numerous issues. Sounds like fun! But my inner Quest apologist-shill-fanboy is giving me the stink eye, darn it!

I bought mine when they first came out from the AT guys at NSL. They lamented not being able to source the thin plastic tubes that came with the Q2G2s. Squishy rubber tubes instead, but they said they would work!

Love ya!

Dave

 

[Art Upton]

In another thread it seems Q-Jet E26s practically all chuff to some extent.

 

[4regt4]

In another thread it seems Q-Jet E26s practically all chuff to some extent.

I got extremely gun shy on the E26 after multiple major failures. But they were all the 080321 date code, which has been well reported as being, well, horrible. They were even banned at our local club. But scouring the MESS reports, it seems very few newer ones are giving problems.

I think I need to revisit the E26.

Hans.

 

[Daddyisabar]

I got extremely gun shy on the E26 after multiple major failures. But they were all the 080321 date code, which has been well reported as being, well, horrible. They were even banned at our local club. But scouring the MESS reports, it seems very few newer ones are giving problems.

I think I need to revisit the E26.

Hans.

What's the procedure your club uses in banning a certain date code on a motor? Do you post it on the website and at the launch? All E26 need RSO pre-approval? Could it be done with Estes E12's too?

 

[4regt4]

What's the procedure your club uses in banning a certain date code on a motor? Do you post it on the website and at the launch? All E26 need RSO pre-approval? Could it be done with Estes E12's too?

It was just simply a "no 080321" on the email notice for the launch. I guess someone could cheat and launch, but we are a very small tight knit group and everyone goes along with what is suggested.

I had some older D22s that I knew might be problematic. I marked the flight card "D22 Qjet, clay nozzle". The LCO (also website admin, statistician, organizer, scheduler, and.....) said over the PA "Hans is launching again. As usual, everybody run and duck."

And it turned out to be a bad motor. Rocket did a loop-de-loop right off the launch rod. Contacted AT, Karl said "Do Not launch the rest of those." So the rest are awaiting an empty field to be fired in the Vortico.

Hans.

 

[Daddyisabar]

It was just simply a "no 080321" on the email notice for the launch. I guess someone could cheat and launch, but we are a very small tight knit group and everyone goes along with what is suggested.

I had some older D22s that I knew might be problematic. I marked the flight card "D22 Qjet, clay nozzle". The LCO (also website admin, statistician, organizer, scheduler, and.....) said over the PA "Hans is launching again. As usual, everybody run and duck."

And it turned out to be a bad motor. Rocket did a loop-de-loop right off the launch rod. Contacted AT, Karl said "Do Not launch the rest of those." So the rest are awaiting an empty field to be fired in the Vortico.

Hans.

I had one new 18mm D that you could hear the igniter sizzle inside. It gave a small puff and out came the igniter. Pulled the rocket off the pad only to discover damage to the poopy clay nozzle. That one did get a Mess report because a tiny "chuff" damaged the motor nozzle beyond reuse. Sooo maddening!

The little devil setting on my shoulder says I should try to repair with some kitty litter and glue, reforming the nozzle. The Angle on the other shoulder says to keep it in the scrap AP box to break up and burn at the special club camp fire were the big boys dispose of their rejected grains. Naughty fun to be had either way.

 

[4regt4]

Happened again. D16FJ-4 18mm 020422-01. This is the first Qjet I've used since the issues I had with them in November. Light rocket (4oz), chuffed very rapidly 4 times, moving up the rod a bit each time. Then it lit, did some real scary sky writing about 10 feet in the air, and took off at a 45deg angle for a very slow, low arc. Lawn darted just before ejection blew. Ground was soft/muddy, so no damage other than scuffed paint on the nose cone. There is some asymmetrical erosion in the nozzle.

Looking at my records, I've not had a successful Qjet in the last 9 attempts. No problems with other motors whether BP or AT reloads. Just these stupid Qjets.

I'm going to give them another chance, as I got some late 2023 dated motors directly from AT. If these fail, I'm done with them.

Hans.

 

[cwbullet]

I am concerned about Qjet chuffs. I might March them out to mid power.

 

[prfesser]

I've mentioned this elsewhere, but remember that APCP burns more slowly when cold. More chuffs in winter months. They can be minimized. Keep motors in an inside pocket or in a small cooler that was loaded with warm bricks until ready to install them. Get it out to the pad, clip up, and push the button. Not frantically but don't waste time. Small motors will cool down more quickly than larger ones.

 

[4regt4]

I've mentioned this elsewhere, but remember that APCP burns more slowly when cold. More chuffs in winter months. They can be minimized. Keep motors in an inside pocket or in a small cooler that was loaded with warm bricks until ready to install them. Get it out to the pad, clip up, and push the button. Not frantically but don't waste time. Small motors will cool down more quickly than larger ones.

Wasn't terribly cold here today, about 50deg. (for a change...). Motors are stored inside my house, transported to the launch site in a heated car. Motor was pre-installed, so the air space in the body tube might provide a touch of insulation.

Hans.

 

[4regt4]

And... I'm now 0/10. C18-4W did a couple of back flips off the pad, went horizontal and landed a short distance away. Was a 041122-01 date code.

At least this one didn't chuff. Very low thrust, it looks like maybe the nozzle eroded. Definitely some material missing off the surface of the nozzle.

Hans.

 

[smstachwick]

And... I'm now 0/10. C18-4W did a couple of back flips off the pad, went horizontal and landed a short distance away. Was a 041122-01 date code.

At least this one didn't chuff. Very low thrust, it looks like maybe the nozzle eroded. Definitely some material missing off the surface of the nozzle.

Hans.

Ouch.

Hopefully the upcoming B14s don’t have this problem with the phenolic. Is there any word on the F41s?

 

[4regt4]

Ouch.

Hopefully the upcoming B14s don’t have this problem with the phenolic. Is there any word on the F41s?

I've long wondered if we'd ever see Blue Thunder in Qjets. I was thinking that perhaps the clay nozzles would be too fragile. Maybe we have the answer to that question ...

Hans.