Estes Wadding Not Ejecting

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brockrwood

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Hi, folks. At my latest launch of LPR rockets at a local park I noticed that that the Estes wadding did not come out of the body tubes on these two rockets:
Cosmic Cobra: BT-56 tube (about 1.3 in in diameter)
Scratch Built: 29mm tube

i used 5 1/2 squares of wadding in the 29 mm and about 5 squares in the Cosmic Cobra BT-56.

Both nose cones came off at ejection. Both parachutes came out.
But the wadding, scorched on one side, stayed in the tube.
Is it supposed to eject?
Is it ok if it doesn’t?
Is there a special way I should insert it? (I just shove it in.)
Should I try a different wadding? Dog barf? Squares of flame resistant crepe paper?
Is there a rule of thumb for how many squares of wadding to use? Am I using too much?
 
How much to use is hard to judge. It is there to protect the recovery materials so if they weren't damaged then you used enough. Too much would be if it is packed in there so tightly that it couldn't come out. If the nose cone and recovery equipment came out then I wouldn't worry about it beyond that. 5.5 squares in those diameters seems good enough to me. You didn't say how long the tubes were- with large volume of tube there isn't enough ejection charge volume in an Estes motor to blow everything out. I've seen a few recent failures because of this.
 
I also often don't get some or all of the wadding, whether Estes or homemade, out upon ejection. I figure as long as the ejection charge provides sufficient pressure and the recovery equipment comes out successfully, it doesn't matter much of the wadding is blown out or not.
 
Motor(s)? Ejection charges vary.

As long as the recovery system is deployed as it should be (and is undamaged) its OK. I'd probably replace the really cooked stuff before the next flight. The rest is certainly reusable.

The amounts seem about right for the size tubes to me.
 
How much to use is hard to judge. It is there to protect the recovery materials so if they weren't damaged then you used enough. Too much would be if it is packed in there so tightly that it couldn't come out. If the nose cone and recovery equipment came out then I wouldn't worry about it beyond that. 5.5 squares in those diameters seems good enough to me. You didn't say how long the tubes were- with large volume of tube there isn't enough ejection charge volume in an Estes motor to blow everything out. I've seen a few recent failures because of this.
The 29mm was 13 inches long. The BT-56 on the Cosmic Cobra’s BT-56 tube is 10” long not counting engine mount or 12 1/2 inches long counting motor mount.
 
Hi, folks. At my latest launch of LPR rockets at a local park I noticed that that the Estes wadding did not come out of the body tubes on these two rockets:
Cosmic Cobra: BT-56 tube (about 1.3 in in diameter)

first, congratulations on getting a successful flight on the Cosmic Cobra. It belongs in the pile of “exceptions” that prove the rule that Estes makes great rockets.

the Cobra body tube is simply too short to hold the blades, the chute, and the wadding. The Cobra is 19.5 inches long, the Helicat is almost the same rocket except they made it longer, 30 inches, and it is comparatively a dream to pack. Anyway, the Cobra is in that select group of “What the heck were they thinking when they designed and sold this” rockets from Estes. It in there with a bunch of rockets with 18mm motor mounts that should have been 24. But I digress…..

doing a little research, based on this I think this is a BT-56 body tube
https://www.rocketryforum.com/threads/bt-56-tube-and-coupler.115217/#post-1323552
options

best is to buy an 18” BT-56, cut two three inch or so long pieces which can be cut and rolled one inside the other to make a coupler (or just buy a coupler, I never have one when I need one so I just make them from body tubes), and extend the rocket another 10 inches or so with what is left. If after construction and finishing you are still under 113 grams loaded with motor and wadding, you are good on a C6-3, otherwise I’d bump to C5-3.

@rklapp is big on Qualman Baffles, and they make one in BT-56 size

http://www.qualmanrocketry.com/Baffle BT plywood.html
but I am not sure lengthwise it would fit without things still being tight.

another option is to get a top flight thin mil chute, which I THINK would fit between the rotor blades easier than the suppled chute. If you do this, and spray it with flame retardant (hey @rklapp , what kind did you use?), stick it between the blades, you probably can get away with only a couple of sheets of wadding, and you MAY even have room for that Qualman baffle.

whatever you try, TEST it first by loading everything but the motor including wadding just like you were getting ready to launch. take a medium breath, put your lips around the plastic nozzle, and see if you can blow out the nose, chute, and laundry. If you can’t do it easily, something is too tight.

good luck, and make sure you designate a spotter for the cone AND one for the rocket. Too often everyone is watching the cone and forgetting about the rocket!
 
first, congratulations on getting a successful flight on the Cosmic Cobra. It belongs in the pile of “exceptions” that prove the rule that Estes makes great rockets.

the Cobra body tube is simply too short to hold the blades, the chute, and the wadding. The Cobra is 19.5 inches long, the Helicat is almost the same rocket except they made it longer, 30 inches, and it is comparatively a dream to pack. Anyway, the Cobra is in that select group of “What the heck were they thinking when they designed and sold this” rockets from Estes. It in there with a bunch of rockets with 18mm motor mounts that should have been 24. But I digress…..

doing a little research, based on this I think this is a BT-56 body tube
https://www.rocketryforum.com/threads/bt-56-tube-and-coupler.115217/#post-1323552
options

best is to buy an 18” BT-56, cut two three inch or so long pieces which can be cut and rolled one inside the other to make a coupler (or just buy a coupler, I never have one when I need one so I just make them from body tubes), and extend the rocket another 10 inches or so with what is left. If after construction and finishing you are still under 113 grams loaded with motor and wadding, you are good on a C6-3, otherwise I’d bump to C5-3.

@rklapp is big on Qualman Baffles, and they make one in BT-56 size

http://www.qualmanrocketry.com/Baffle BT plywood.html
but I am not sure lengthwise it would fit without things still being tight.

another option is to get a top flight thin mil chute, which I THINK would fit between the rotor blades easier than the suppled chute. If you do this, and spray it with flame retardant (hey @rklapp , what kind did you use?), stick it between the blades, you probably can get away with only a couple of sheets of wadding, and you MAY even have room for that Qualman baffle.

whatever you try, TEST it first by loading everything but the motor including wadding just like you were getting ready to launch. take a medium breath, put your lips around the plastic nozzle, and see if you can blow out the nose, chute, and laundry. If you can’t do it easily, something is too tight.

good luck, and make sure you designate a spotter for the cone AND one for the rocket. Too often everyone is watching the cone and forgetting about the rocket!
Thanks for all of these great tips and suggestions!
 
whatever you try, TEST it first by loading everything but the motor including wadding just like you were getting ready to launch. take a medium breath, put your lips around the plastic nozzle, and see if you can blow out the nose, chute, and laundry. If you can’t do it easily, something is too tight.
I had a humiliating problem trying to do the “use a puff of breath” test recently. I tried to do it on the scratch built 29 mm rocket. Nope. The rocket has swept back fins. My now fat face and big head doesn’t fit between the fins. Doh! Embarrassing. The next time I build a rocket with swept back fins I will have to put in the motor mount and do this test before I put on the fins.
 
first, congratulations on getting a successful flight on the Cosmic Cobra. It belongs in the pile of “exceptions” that prove the rule that Estes makes great rockets.

the Cobra body tube is simply too short to hold the blades, the chute, and the wadding. The Cobra is 19.5 inches long, the Helicat is almost the same rocket except they made it longer, 30 inches, and it is comparatively a dream to pack. Anyway, the Cobra is in that select group of “What the heck were they thinking when they designed and sold this” rockets from Estes. It in there with a bunch of rockets with 18mm motor mounts that should have been 24. But I digress…..

doing a little research, based on this I think this is a BT-56 body tube
https://www.rocketryforum.com/threads/bt-56-tube-and-coupler.115217/#post-1323552
options

best is to buy an 18” BT-56, cut two three inch or so long pieces which can be cut and rolled one inside the other to make a coupler (or just buy a coupler, I never have one when I need one so I just make them from body tubes), and extend the rocket another 10 inches or so with what is left. If after construction and finishing you are still under 113 grams loaded with motor and wadding, you are good on a C6-3, otherwise I’d bump to C5-3.

@rklapp is big on Qualman Baffles, and they make one in BT-56 size

http://www.qualmanrocketry.com/Baffle BT plywood.html
but I am not sure lengthwise it would fit without things still being tight.

another option is to get a top flight thin mil chute, which I THINK would fit between the rotor blades easier than the suppled chute. If you do this, and spray it with flame retardant (hey @rklapp , what kind did you use?), stick it between the blades, you probably can get away with only a couple of sheets of wadding, and you MAY even have room for that Qualman baffle.

whatever you try, TEST it first by loading everything but the motor including wadding just like you were getting ready to launch. take a medium breath, put your lips around the plastic nozzle, and see if you can blow out the nose, chute, and laundry. If you can’t do it easily, something is too tight.

good luck, and make sure you designate a spotter for the cone AND one for the rocket. Too often everyone is watching the cone and forgetting about the rocket!
My guess is that the blades pushed back the pressure wave. The wadding occasionally will get stuck but don’t think it’s a problem as long as the laundry deploys. I probably wouldn’t use the baffle with the blades. I’m always overthinking how far down to push the Qualman baffle. Too far will blow the pressure out the nozzle like @BABAR said. Not enough means limited space for recovery. It’s more of an art than science. 😀
 
the Cobra body tube is simply too short to hold the blades, the chute, and the wadding. The Cobra is 19.5 inches long, the Helicat is almost the same rocket except they made it longer, 30 inches, and it is comparatively a dream to pack
I have a couple of Cosmic Cobra’s I got on sale somewhere a few years back. Maybe I can kit bash two of them together and make a “Stretch Cobra”?

My other problem with the Cosmic Cobra is that sometimes one of the autorotation blades fails to unfold. I am using fresh rubber bands so I know the rubber band is good. But there is an annoying “lip” on the hinge of the blade. Sometimes the rubber band gets hung up on that lip and keeps the blade from swinging into the “full upright and locked position”. Maybe I can file it off…
 
I have a couple of Cosmic Cobra’s I got on sale somewhere a few years back. Maybe I can kit bash two of them together and make a “Stretch Cobra”?

My other problem with the Cosmic Cobra is that sometimes one of the autorotation blades fails to unfold. I am using fresh rubber bands so I know the rubber band is good. But there is an annoying “lip” on the hinge of the blade. Sometimes the rubber band gets hung up on that lip and keeps the blade from swinging into the “full upright and locked position”. Maybe I can file it off…
Red Five, standing by...
 
Brock, I've had countless times where the wadding wasn't blown out. As long as the recovery gear opens then I wouldn't worry about it. A lot of times the upper sheets of wadding are still reusable. As for why it happens, at this point I feel like i'm pretty consistent with how I pack the wadding so I don't believe it is an issue with how it's inserted or how much is used but both could be an issue if you over do it.

I feel like the issue is more with the inconsistency of the ejection charge. I'v had some that were so strong they blew the nose cone off the rocket ripping the shock cord off the nose cone while others barely popped the nose cone. Recently flew a C5-3 in rocket that has flown more than 30 times. The ejection only pushed the nose cone out and the rocket thankfully tumbled back with no damage. Checked the fit of the cone and found no issues after the flight.
 
I'm surprised nobody pointed this out but Estes instructions tell you how many pieces of wadding you should use (I don't know if they *ALWAYS* do, but I don't know of a single kit that, if it's needed, doesn't mention it).

1654796999644.png
 
Assuming the motor didn't have a really anemic ejection charge (and inconsistency there is a VERY real problem), if the chute deploys but some of the wadding doesn't come out, whether Estes style or dogbarf, it means the wadding wasn't compressed into enough of a "plug" to give a piston effect. When the wadding separates like that, there is increased risk of burning particles and hot gas getting through and reaching the sensitive bits. Getting the packing compression right is a bit of an art and depends on the wadding type. With dogbarf, I like to drop a 1/2" or 3/4" dowel on top of the wadding from a few inches up to tamp it down slightly. It doesn't need much force. For the Estes type wadding, it wants to be actively compressed a bit. With either type, I use the same stick to gauge the depth of the wadding in the tube to make sure it's enough.

Competition flyers often use tethered pink foam plugs to make a real piston. They are near 100% effective and will get the laundry out with very weak ejection charges, but they are not compatible with tri-fold shock line mounts.
 
Competition flyers often use tethered pink foam plugs to make a real piston. They are near 100% effective and will get the laundry out with very weak ejection charges, but they are not compatible with tri-fold shock line mounts.
What are some other drawbacks with using foam plugs to form an ejection piston besides interference with a shock cord mount located above the foam piston plug?
 
What are some other drawbacks with using foam plugs to form an ejection piston besides interference with a shock cord mount located above the foam piston plug?
They're a little more work because you need to tether them so they don't litter up your field (fine kevlar pushed thru the middle with a needle). I think you can buy them from Apogee; I machined cutters for 13/18/24mm plugs and cut my own. For larger diameters you would need to get foam thicker than 1" which is more difficult to buy in reasonable quantities. The last time I got the 1" pink foam it was on the shelf at HD or Lowe's in 24" squares.

It's critical to use extruded foam (Corning pink type or some blue types) rather than the typical cheap white expanded fused-bead type which will disintegrate upon ejection.
 
They're a little more work because you need to tether them so they don't litter up your field (fine kevlar pushed thru the middle with a needle).
Where do you anchor the end of the Kevlar line that isn't connected to the foam plug?
 
Where do you anchor the end of the Kevlar line that isn't connected to the foam plug?
Just tie it to the shock line. The tether cord will sit completely behind the plug when packed.

I forgot to mention that you need to do something to prevent the line from pulling back out of the plug - you can tie it around a little crossbar, or cut a small disc from light plastic (yogurt cup gauge), put a pinhole in the center for the cord and knot the tether line to keep it from passing back through.
 
I had a humiliating problem trying to do the “use a puff of breath” test recently. I tried to do it on the scratch built 29 mm rocket. Nope. The rocket has swept back fins. My now fat face and big head doesn’t fit between the fins. Doh! Embarrassing. The next time I build a rocket with swept back fins I will have to put in the motor mount and do this test before I put on the fins.

Hang onto those yellow Estes tubes. Or use an old engine drilled out.
 
Might use a modification of @BlaineS technique for foam earplug shock cord zipper proofing

https://www.rocketryforum.com/threads/blaines-kevlar-anti-zipper-using-foam-ear-plug.154996/
gives more surface area to glue onto, and something tougher for the Kevlar knots to pull on.

I was thinking hardware stores may have some broken pieces of insulation board that they’d give you for free, or a reduced price, sort of like getting broken bales of wadding.

back to original post, hate to have you use two rockets to build one, but I think the Cobra was BT-56 tubing, so hard to find a matching extension unless your can roll your own.
 
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