Breaking down an Estes Engine

snip

After considering all the advice posted on rmr, I decided to pulverize the engine slug that I had removed from the casing. I placed it between a couple of sheets of wax paper and used a wooden hammer handle to carefully crush it. The slug was impressively hard and compact but after a little patience, I managed to break it down to a fine powder. We had lots of powder left over. Much more than I used. The rocket was prepped at home and I placed just enough powder in each engine, to cover the tops of all 6 booster engines of the 1st and 2nd stages.

Verna, our son Louis and myself, met BRB club founder Ron Witherspoon at the field about 1:00pm. The temp 84*, sky dark overcast clouds and the winds were out of the south, gusting to 10 mph. We got set up quickly as we tried to get a couple of flights in before the coming rain caught us.

As usual, the 3rd flight of Bad Girl had a great liftoff and all 5 C6 engines boosted it nice and straight to about 100'. I got a pretty good shot of the liftoff just as she was clearing the rod with all 5 engines burning brightly. As she reached about 100' she staged but we only got 3 of the 5,

2nd stage engines to ignite, all outboards. We missed the 2nd stage core engine which again prevented the 3rd stage engine from having a chance at all.

The first stage tumbled down and bounced in the damp grass with little sign of wear, only 1 fin popped off, that will be easily repaired. The second stage ejected both chutes but 1 stripped. Fortunately, it only needs 1 of the 2, so that was no problem either. Last time we managed to get all 4 outboards without any extra powder at all. The 3rd stage came in nose first but also landed in some high damp grass and had no damage at all. Over all the rocket needs a fin reattached and we're ready to go again.

It would appear that the extra powder had little or no effect and isn't necessary. After reviewing all 3 flights and considering what worked and what failed, I think I do finally have an answer for our problem of missing the core engines, all 3 times. After 3 flights, I know the bird is stable and all the modifications we made to convert it to a 3 stager are correct and work very well.

So what's the problem? My theory is:

I believe the reason that we can get the B4-2's to ignite and keep missing the core B6, is that the B4's have a larger nozzle opening than the B6 booster. I'm pretty sure that if we could acquire a B4-0 booster or something similar, I could get all 5 of the second stage engines to go and also get the 3rd stage too.

Does anyone here know if a B4-0 or something similar has ever been produced?

Randy

Yes there is enough energy to set it off. You may get away with it multiple times but one time it will go off. That is how accidents happen. Dampen it and then crush it while it is damp.

KT

If you just use black powder or pyrodex as it comes in the can you will separate the stage without ignition. It will act as an explosive separating the stage but not have enough contact duration to light off the next engine. If you are going to use Black powder you must get rid of the grains by adding water to make a thick clay consistency (not to much water) desolving the grains and making it less of a fast burn explosive. Then take that and fill the nozzle. Let it dry and wala. You are ready to go.

KT

Good way to take some fat of the butt or take the fingers off. Never put black powder under pressure without it being damp or rendered insensitive by some means. You could do the suggested though if you do it remotely and protect yourself from flying objects. I work at a Rocket factory and I would be fired for suggesting such a stunt.

Point taken... I've never really considered doing it...

I've also thought the same way. Scratching at the BP slug then using a pesil & mortar to make it into a fine powder. How much water would you soak the slug in? And wont soaking it make it burn a lot slower? I think soaking it would result in the soaker having to have alot of meshing to do to get the bp into a fine powder :twisted:

Estes Motors are made up of :

Potassium Nitrate 71.79% Sulfur 13.45% Charcoal, 150 mesh 13.81% Dextrin .95 %

[u:1b84a60d3a]Real Gun BP is made up of :[/u:1b84a60d3a]

Potassium Nitrate 75% Sulfur 10% Charcoal 15%

I would not risk disecting a rocket motor, but get yourself some of the BP from a gun store. And then you can experiment with different amounts of Charcoal / Dextrin to act as a binder and to slow the burn rate of your motor down, changing the impulse of the motor. You could even make your own delay charge by using Kno3 & Suger, and experimenting with the amounts to suit your delay. And use like 600 mesh BP as a ejection charge.

Karl

*-----------------------* Posted at: *-----------------------*

You don't need water. Use a brick to grind it. No hard pounding, no heavy force.

The water evaporates but it takes a week or more to sufficiently evaporate. Estes IIRC uses 2 months.

Who told you this?

It was on another thread on this forum, under the Pyrotechnic part. Heres the link :

*-----------------------* Posted at:

*-----------------------*

snip

My pc went down 10 days ago and I've just now gotten everything back and running.

Ok, I have some new information on this post.......

When I first posted my flight report I had only glanced at the engines of the different stages. I finally had a chance to sit down and carefully go over the rocket last Saturday and I found that for the first time, the 2nd stage core engine DID ignite. The reason I missed it at first glance, is that the nozzles of the other four 2nd stage engines, (all B4-2's) had a good deal of exhaust particles on them but the core B6-0 looked clean.

After I removed all the engines, from all 3 stages, I found we had gotten 10 of the 11 to ignite, which was a slight improvment over the last flight. The only one we missed was the 3rd stage B4-2. I now believe that the small amount of powder I added to the C6-0 of the 1st stage core engine, actually helped ignite the B6-0 core engine of the 2nd stage.

After close inspection of the engines of the last 2 flights, it's glaringly obvious to me now, that the difficulty in igniting the B6-0 engines is that the nozzles are noticeably smaller than the B4 series. The B4's are easily ignited, even chad staging them 10.5" apart, as long as the tubes and main bt are adequately vented.

The rocket sustained only minor damage to 1 fin. It has been repaired and we'll try again. I think I would have a simple solution, if there were just a B4-0 on the market but I don't know if there ever has been such an animal produced by any company. If anyone here knows of a substitute please speak up.

I have received many emails in the last 10 days that I have been unable to respond to until now. Some requesting information for building something similar, so go here:

people that have requested specific information, I will get it to you by this weekend.

And some saying the launch photo on abmr is blurry and requesting a repost of the girl on the rocket. Since the requests for the photo were worded very nicely, I'll ask Verna to repost the actual photos used to make the water slide decals. Please keep in mind that she is normally very shy and the mother of 5. I think she looks pretty good all things considered, especially when compared to most of the other rocketeers we fly with. ; )

Randy

Actually... yes. ; ) And you wouldn't want me to think otherwise either, would you?

Randy