How much 'dog barf' do I use?

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CrazyOB

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All,
I am impressed by the 'over acheiving' ejection charge on Estes engines. It has been awhile but I do not remember 'loud pops' for ejection. Anyway, after melting a couple of chutes today with the crappy toilet paper :flyingpig:, how much dog barf do I use? I am flying BT-50's with B or C's right now. Thanks and happy flying.
 
My two cents... I use two to three calibers of dog barf. I had a couple of scorched chutes with only one caliber.
 
Indeed the dogbarf is less expensive but like Jim I've been using Nomex a lot for HPR - quicker to prep and it takes much less room in the tube. For LPR competition I've just made a batch of foam piston/plugs for BT-5/20/50 sizes. The Internats people have been using these for a while. They work great, 100% protection for very little mass, and guard well against motors with too weak/strong ejection. However you can't use an obstructive internal shock cord mount. Dogbarf in small diameter tubes with poly chutes is tricky unless you put something more cohesive behind it.
 
I still use some "dog barf" in my HPR rockets 4" or less in diameter to give addtional protection to the nomex which does wear out eventually, the dog barf is an cheap life extender. I also use it with my borated duckcloth canvas chute protectors and get great results, I can buy and borate a full yard of duckcloth for what a single 12"x12" Nomex protector costs.
 
I used dog barf yesterday for the first time and was very pleased with it; I had 2-3 calibers in there, not sure exactly, and the chute came out completely clean (and cleanly). For LPR it seems perfect.

The only problem I had was getting it in the tube; I was just barely able to get it into a BT-50 without spilling too much; didn't even try with a BT-5 mini rocket. Next time I'll have some sort of cone or funnel handy so I can just throw a handful into the funnel and then squish it into the tube.
 
I used dog barf yesterday for the first time and was very pleased with it; I had 2-3 calibers in there, not sure exactly, and the chute came out completely clean (and cleanly). For LPR it seems perfect.

The only problem I had was getting it in the tube; I was just barely able to get it into a BT-50 without spilling too much; didn't even try with a BT-5 mini rocket. Next time I'll have some sort of cone or funnel handy so I can just throw a handful into the funnel and then squish it into the tube.

Ever try to use a chopstick or even a dowel as a ramrod? Just like old style, front load muskets. Works well for me.
 
I keep a large ziploc bag with the stuff in it. Crumble and breakup the chunks as you are filling the bag. Take a small portion in the palm of your hand, about 1 caliber, and with the rocket horizontal push pour or scoop into body tube.

I fly several BT-50's and hold rocket horizontal with thumb and index finger of hand with barf in palm. Then use opposite index figure to shove into tube and also to reload hand with rocket. Very little spillage but it is inexpensive in the first place.

Just gets the girlfriend screaming though :p " I just vacuumed you doofus!"
 
ClusterBomb said:
Ever try to use a chopstick or even a dowel as a ramrod? Just like old style, front load muskets. Works well for me.

Once I get the darned stuff into the tube I'm OK.

I keep a large ziploc bag with the stuff in it. Crumble and breakup the chunks as you are filling the bag. Take a small portion in the palm of your hand, about 1 caliber, and with the rocket horizontal push pour or scoop into body tube.

I didn't try doing it horizontally like that, which makes me feel stupid. I'll do a practice run in the basement and see how it goes. Still, I think a little paper cone would make it super easy. I'll experiment.
 
I make a cone with one hand and inset the wadding with the other hand. I hold the rocket vertically.

Once I get the darned stuff into the tube I'm OK.



I didn't try doing it horizontally like that, which makes me feel stupid. I'll do a practice run in the basement and see how it goes. Still, I think a little paper cone would make it super easy. I'll experiment.
 
Just don't get it wet. A few years ago someone posted here about having a bag in his car that had gotten wet. It started to mold. He got pulled over by the cops for a traffic violation. Cop saw the baggie filled with stuff that was now green from the mold. The rocketeer had lots of splainin' to do to avoid an overnight stay at the local police station.
 
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