Q-Jet E26-7 motor sputtering

[Dave S.]

I launched an Estes Goblin a couple times on Q-jet E-26 motors today.

Both of them had a couple of seconds of sputtering at the start. Eventually both motors seem to catch good and the launches went well. However I was wondering about the sputtering at the very beginning right after the igniter went off.

Do you think it was a problem with the motors or is it maybe the igniters?

Both motors worked fine in the end but it was a little sketchy for the first second or two.

 

[kuririn]

That is called a chuff. Happens with composite motors sometimes.

 

[kuririn]

PS Just make sure the igniter is all the way to the front of the core when you install it.

 

[Ronz Rocketz]

It happens. We were just remembering when Helens rocket turned into a burnt burrito last March on an E26. If it sputters out and fails to launch, best practice is to use a paper clip and score the insides then try again. If that doesn’t work, ask Karl at Aerotech for a replacement.

 

[kuririn]

My Mega Der Red Max on a composite G motor.
Is this what happened to your motors?

 

[Dave S.]

This is video. It’s not that bad really but I’m used to Aerotech or Estes motors that pretty much just go. Is the fault w the propellant in the motor or the igniter not having enough heat output?

 

[jmasterj]

Looks pretty normal to me. I couldn't see much chuffing.

 

[kuririn]

It's like us.
Sometimes we burp, sometimes we hiccup.
It happens.

Sometimes we fa.........
Never mind.

 

[dpower]

There was some sputtering, the ones I've flown have lit quite fast. Was the pyrogen on the igniter fully intact? Were the igniters inserted fully, until they touched the delay grain? It's easy to damage the pyrogen on Q-Jet igniters, they're much more fragile than other types of commercial igniters (StarTech, First Fire Jr.).

 

[Dave S.]

That video I posted was from the 2nd of two flights that day w/ same rocket and same motors. No video of the 1st flight but the chuffing was worse on that one.

 

[Joekeyo]

You think you have problems.
Chuffing, it happens

 

[Dave S.]

Fully inserted and intact

 

[Ronz Rocketz]

Here's my best chuffing motor. I turned the original video into a short but can't find the original.

 

[smstachwick]

The E26 motors use White Lightning propellant, which is well known for oxidizing after prolonged or improper storage and being stubborn on the pad.

Ron’s suggestions to use a paper clip might be helpful, scuff up the surface a bit and expose a new layer. After having this happen with an E16W reload I’ve decided to do this with all my W motors, swapping igniters is no fun.

 

[dpower]

The E26 motors use White Lightning propellant, which is well known for oxidizing after prolonged or improper storage and being stubborn on the pad.

Ron’s suggestions to use a paper clip might be helpful, scuff up the surface a bit and expose a new layer. After having this happen with an E16W reload I’ve decided to do this with all my W motors, swapping igniters is no fun.T

The Q-Jet "White" motors use a propellant called "Fast White", different than standard WL. They're less susceptible to oxidation and chuffing in my experience:

https://www.oldrocketforum.com/showpost.php?p=237789&postcount=8

https://www.oldrocketforum.com/showpost.php?p=238735&postcount=28

 

[4regt4]

In the past, all the Qjets that I've tried chuffed at least a little, if not a lot.

But as soon as I started dipping the igniters in ProCast, I've had zero delays or chuffs, and no complete misfires.

Hans.

 

[Ronz Rocketz]

In the past, all the Qjets that I've tried chuffed at least a little, if not a lot.

But as soon as I started dipping the igniters in ProCast, I've had zero delays or chuffs, and no complete misfires.

Hans.

For me, chuffing hasn't been an issue as much as cracked nozzles in the 18mm and the E26/D22 motors. There's speculation that Quest hasn't spent as much on their LPR motors as they should have. They started a new clay formulation in Nov 2021 so hopefully fixed the problem. I'm not sure since I haven't bought Quest motors for some time with the clay nozzles. I got tired of my rockets going into cruise missile mode. I have bought several F44W and F67W lately. I'm hoping to launch a few on Monday.

 

[Bill S]

For me, chuffing hasn't been an issue as much as cracked nozzles in the 18mm and the E26/D22 motors. I have bought several F44W and F67W lately. I'm hoping to launch a few on Monday.

I''ve had several launches with the F44 and F67 motors in the last few months, no issues at all, unlike my previous bad experiences with the Q-Jets. I saw plenty of cruise missiles (lost one that way), and lots of CATOs.

 

[AeroTech]

This is video. It’s not that bad really but I’m used to Aerotech or Estes motors that pretty much just go. Is the fault w the propellant in the motor or the igniter not having enough heat output?

It can happen if the initiator isn’t completely forward in the core. It can also be worse if the propellant is cold as it will burn more slowly.

 

[AeroTech]

You think you have problems.
Chuffing, it happens

Best chuff video ever.

 

[AeroTech]

For me, chuffing hasn't been an issue as much as cracked nozzles in the 18mm and the E26/D22 motors. There's speculation that Quest hasn't spent as much on their LPR motors as they should have. They started a new clay formulation in Nov 2021 so hopefully fixed the problem. I'm not sure since I haven't bought Quest motors for some time with the clay nozzles. I got tired of my rockets going into cruise missile mode. I have bought several F44W and F67W lately. I'm hoping to launch a few on Monday.

Well, let me clear up the “speculation”. We spent far more time and money on the Q-Jets than we should have. My former business partner, who was a supposed expert on clay nozzles, recommended the particular brand and type of clay that was used in the first Q-Jets. After we discovered that the clay was a hygroscopic sodium bentonite that swelled in high humidity, we embarked on a search for a clay that did not exhibit those properties. That is what we have been using for over a year.

 

[user 35280]

You think you have problems.
Chuffing, it happens

Thrust vectoring test

 

[StreuB1]

Are the clay nozzles compression molded or are they done with some type of transfer molding?? Do they need firing to vitrify or do they just dry?

Is the cost differential of the clay vs a cheaper phenolic blend done with transfer molding that high? I don't know the sales volume on these so I assume its not high enough to offset the cost of doing a cheaper compound phenolic nozzle.

 

[AeroTech]

Are the clay nozzles compression molded or are they done with some type of transfer molding?? Do they need firing to vitrify or do they just dry?

Is the cost differential of the clay vs a cheaper phenolic blend done with transfer molding that high? I don't know the sales volume on these so I assume its not high enough to offset the cost of doing a cheaper compound phenolic nozzle.

The clay is a powder that is pressed dry. It is far cheaper than a phenolic nozzle from a materials perspective, but there is currently more labor involved in the pressed clay nozzle. That could change in the future.

 

[Ronz Rocketz]

Well, let me clear up the “speculation”. We spent far more time and money on the Q-Jets than we should have. My former business partner, who was a supposed expert on clay nozzles, recommended the particular brand and type of clay that was used in the first Q-Jets. After we discovered that the clay was a hygroscopic sodium bentonite that swelled in high humidity, we embarked on a search for a clay that did not exhibit those properties. That is what we have been using for over a year.

Clears that up. I do have motors with 111121 and 11121 date codes, so is the later January 11th or November 1st? Either way, would it have the new clay formulation?

 

[Ronz Rocketz]

I''ve had several launches with the F44 and F67 motors in the last few months, no issues at all, unlike my previous bad experiences with the Q-Jets. I saw plenty of cruise missiles (lost one that way), and lots of CATOs.

To clarify for all, the F44 and F67 have phenolic nozzles and are awesome motors. So are the E20W and E30T.

One issue with the initiators is that if you push too hard, it crumples the tip and not clear how this impacts the initiators ability to light the propellant. The dark heatshrink is a good guide.

 

[AeroTech]

To clarify for all, the F44 and F67 have phenolic nozzles and are awesome motors. So are the E20W and E30T.

One issue with the initiators is that if you push too hard, it crumples the tip and not clear how this impacts the initiators ability to light the propellant. The dark heatshrink is a good guide.

Q-Jet Initiators produced during the last couple of years have a protective coating that makes them much stronger than before. Regardless, I would not “push” the initiator once past the nozzle throat, rather let it drop naturally into the core to the specified depth, bend it over and secure in place.

 

[AeroTech]

Clears that up. I do have motors with 111121 and 11121 date codes, so is the later January 11th or November 1st? Either way, would it have the new clay formulation?

Let’s see a picture of the nozzle. The original clay was very light-colored and uniform, the new clay is somewhat gray-ish with darker speckles throughout.

 

[Ronz Rocketz]

Q-Jet Initiators produced during the last couple of years have a protective coating that makes them much stronger than before. Regardless, I would not “push” the initiator once past the nozzle throat, rather let it drop naturally into the core to the specified depth, bend it over and secure in place.

I know what you're saying. The new stronger tips seem a bit thicker and shinier/glossier. I've had better success with these and less chuffing. Unfortunately most of the initiators I've seen are the old crumbley type.

 

[Ronz Rocketz]

Let’s see a picture of the nozzle. The original clay was very light-colored and uniform, the new clay is somewhat gray-ish with darker speckles throughout.

None of the 24mm E26 and D22 have the dark clay. One is labeled 111021 so guess this was just before the new formulation. Lucky me...