It=2.72N-s Fav=1.52N tb=1.75s
 

Those are the results from the second prototype A1.5-0 10mm engine! A little too hot for an A, but that was improved with third which was 2.50N 1.51N and 1.66s. There still is .6" left over in the tube for delay and EC. That will probably limit a full A to about 6 seconds max.

The thin wall cases do hold up. I was afraid that since they are about .050", they would cato or burn-through. So far, all the tests are positive.

An old Estes A8-3 on the stand was 2.2N-s with a .52s burn.

There is still a lot of work to do!

Were these made by a machine or were they hand loaded?

By hand with parts that will be used on the machine.

The 10mm and 13mm will be done on a different machine than the 18mm engines.

Put me down for a 12 pack :D

Seriously, I guess the case dimensions dictate other dimensions such as nozzle opening and burning surface area such that when it's all said and done, 10mm motors tend to all have the thrust curve Carl attached. I say (ask) that because the curve looks very much like the old Apogee micro motor curves.

Doug

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That is exactly right. I would be surprised if they were much different.

Too kewl! :cool:

Great news, Carl!

Please be sure to get your motors California certified so I can fly them. ;)

Bob

Very cool.

I have a generic question relating to your motors(this may have been discussed already-not sure).... what is the process for making the nozzles and how are were they made for the prototypes? This question has nothing to do with the prototype test results, I'm just curious how certain aspects of the motors are(or will be) manufactured since I don't know much about the process.

That would make a very nice boost glider motor. :) Thanks for the update Carl!

I like it! So will the rest of the community, especially NAR and International competitors!

Please sir, we want more! :D

Chas

Carl,
You mentioned that the casing walls are holding up to the burn. Will a six-second delay burn possibly cause too much erosion? I know that it is dynamically less damaging, I was just thinking about the heat. Perhaps the char from the propellant burn will provide some heat protection.

Guess you'll just have to make and test a few.

Chas

A 6-second A? I'll fly a bunch, but am not sure I've got the attention span to track anything that flies on one of your C's when you release them. You'll certainly never get these into Wal-Mart, so that Estes acquisition might not be such a hot idea.

The nozzle is made of clay. It looks like kitty litter before it is compressed. When it is pressed, like the black powder and delay, its density almost doubles and it is a very hard slug. The divergent cone and throat are pressed into the base of the clay by a steel drift or die to give it the correct shape.

We will HAVE to get them CA certified or no one can fly them in competition! :D

That is 6-second delay. The burn time is about 1.6 seconds.

I am looking at a 2 second delay before the actual burn for an upper stage engine. The booster would ignite the upper stage, then drop off. The sustainer would produce just enough gas to drop the base pressure for 2 seconds or so to allow it to act as a boosted dart, then after the velocity burns off some, the actual burn would start. For B altitude, I have always wondered if this would help. I was working on that with 13mm engines in the early 70's when the rug got pulled.

I suppose I could fly the combination in Rocksim, but it is not the same without the sulfur smell.

Rocket simulations - who needs 'em? The guy over in the "Ask Mike" forum said that HE don't need no stinkin' sim program, so why should any of the REST of us use one!

Simulation software - feh!

Just set them up on Semroc's remote corporate rocket range, retreat into the heavily-reinforced blockhouse that you have on site, press the button, and see what happens!

:D :D :D

MarkII

I was wondering if I was the only one that saw the humor in that.

When Telex hired me in 1971 as a final test technician, I convinced the guy in personnel that I knew a lot about logic design because I had read a few books. I aced the test and started the next day. My new supervisor told me that my oscilloscope was on order. I told him, essentially, that i did not need no stinking scope; I could see ones and zeros with a meter, if he just told me how many volts a zero was and how many volts a one was. He went over to his office, pulled a few hairs out, and came back and asked me if the guy that hired me had told me about the 90 day probation period. He suggested that if I really did not know how to use a scope, I had better learn pretty D**N quick.

From that point on, I have always been willing to add any new tool to my toolbox and learn how to use it. All the people that I worked for initially and that I supervised later were stuck in the same groove of "I don't need anything that I did not have 20 years ago."

I can look at a box and tell you how much it weighs, but the post office prefers that I use a "stinkin" scale as a cross-check! :chuckle:

Being one of the primary targets of that short-range tactical strike :D I thought it was kinda funny, too. Sad, but funny...

Carl, what sort of final weights (with delay charges loaded) are you expecting the complete engine to reach? I'm trying to force-feed your numbers into the RockSim engine editor, so I can start excessively relying on my simulations of this engine.

Just estimates:

Casing and nozzle 1.5g
BP for A 3.3g
Delay 5 sec 1.0g
E/C & cap .7g


So:
A1.5-0 about 4.8g + about .3g extra BP for blow-through
A1.5-5 about 6.5g
2-A1.5-5 about 6.9g (2 second delay before BP)

Booster will probably have larger spike than sustainer.

Thanks, Carl!

But you're smart not to let the tool replace common sense. On the TARC Yahoo group someone wanted to know what was wrong with his altimeter. RocSim said the rocket would go to 800' and it only went to 600' so something had to be wrong with the altimeter.

Many tools are worse than useless until you learn when and how to use them and understand their limitations (and yours.)

Wow, extra BP for blow thru. Better not let MicroPicture find out that you do that. He'll have a cow, then he'll post some impossibly tiny pictures to support his position :D

Doug

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What all types of logic did you work with, Carl? I'm guessing DTL and RTL were the common types in the early 70s.

For me, coming out of school in 83, LS-TTL was king, and was soon replaced by FAST-TTL. I did many board designs with that back in the late 80s. That technology will always be my paradigm.

I was actually a bit saddened a few years ago when I learned that all bi-polar logic had gone by the wayside

Doug

(And no, Bill, bi-polar logic is not the term used to describe how schizophrenics think )

.

We had to interface with some old IBM RTL logic boards, but everything we did from 1971 was TTL. 7400 series was on all the production boards when I started. I remember that I had to memorize most the Texas Instruments TTL Databook so I did not have to keep looking everything up. My first computer I built in 1973 was all 7400 series I.C.'s. The most complex part was the 74181 arithmetic unit. It executed the PDP-8 instruction set. I used it at home, but I could not get anyone at Telex interested in building "toy computers." :chuckle: When Intel introduced the 8008 microcomputer, I built a 7400 based board that executed the 8008 instruction set at 20 times the speed. Still no interest from Telex. The good part about it is that I always had a faster and better microcomputer in my basement than you could buy on the market. :D

I still design with 74HCT as glue. I just can't see the numbers on the surface mount parts. The sick joke is that as the early logic designers lose their eyesight, the IC companies make the parts even smaller. I used to laugh at my elders at Telex that carried a jeweler's loupe to see the parts back then. I did not realize I was laughing at my future self as well.

Who is Micropicture?

MicroMeister. He threw a fit a while back (on another forum) when it was suggested that some motor makers added a little extra powder in their boosters to guard against early burn-thru (thereby ensuring the same impulse level as like motors with delay). (I'm under the impression that some do/did, and some don't/didn't - ie, that it varied amongst motor makers.)

The "picture" reference has to do with the fact that his pictures are usually so shrunken as to be illegible

Doug

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I didn't realize it went back that far.


I still have mine. It was a required text book in college, believe it or not.


I was surprised by that attitude in college. The professors were focussed on 500khz 6800 microprocessors, and even then I realized I could roll my own CPU out of discrete logic and bit slice that could run 10 or 20 or maybe even a 100 times faster. I think that was probably still true until the 68020 or 486's came along. Heck, Cray was still doing it that way for another few years until 500MHz processors overtook his stuff.


It's even worse now with laser branding. It's danged faint. And the light must hit it just the right way to get a good read. I actually have to use a stereoscope in the lab sometimes

Even then, that parts are so small now that we have to create encoded part numbering tables in the datasheets. The user reads a 4- or 5-character number off the IC package, then looks it up in the datasheet to get the complete umpteen character part number. If you don't already know the root part number, you won't know which datasheet to use. In some ways, the parts might as well be not branded

I don't think the various divisions within the company here cooperate on the encoded strings, so two entirely different parts, such as an op-amp and a temp sensor, which happen to share the same tiny package, such as a SOT23-6, might have the same encoded marking. So even if you can read the number, you still won't figure out what it is

Doug

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Quickie A2 Test Rocket
 

Here's what RockSim suggests the flight performance could be for the A2-5. There may still need to be some tweaking with the numbers, as I think the RS engine editor is forcing slightly higher impulse and thrust values than what Carl gave earlier. Not by a whopping amount, but enough that the simulated performance might be a bit hot.

Design specs can be found on the 2D plan view. Launch rod was set at 48", but the model as-shown will launch from a 36" x 1/8" rod.

Carl,

Thought you could use a little inspiration.

Here's a picture of the casting mandrel for a little something NASA's hard at work on these days. :)

All of this "logic" talk makes me hungry for a little "Breakfast"... ;)

"When I was young, it seemed that life was so wonderful,
a miracle, oh it was beautiful, magical.
And all the birds in the trees, well they'd be singing so happily,
joyfully, playfully watching me.

But then they send me away to teach me how to be sensible,
logical, responsible, practical.
And they showed me a world where I could be so dependable,
clinical, intellectual, cynical.

There are times when all the world's asleep,
the questions run too deep
for such a simple man.
Won't you please, please tell me what we've learned
I know it sounds absurd
but please tell me who I am.

Now watch what you say or they'll be calling you a radical,
liberal, fanatical, criminal.
Won't you sign up your name, we'd like to feel you're
acceptable, respectable, presentable, a vegetable!

At night, when all the world's asleep,
the questions run so deep
for such a simple man.
Won't you please, please tell me what we've learned
I know it sounds absurd
but please tell me who I am."

MarkII

Ah yes, probably my favorite Supertramp album and my favorite song on the album.

Another early design for the A2. This time, a tri-cluster...

I just call it "Scruffy"...

Altitudes of 961' with a Dv of 6 FPS or less, and flies from a 36" x 1/8" rod...

Enjoy!

Too funny
 

:chuckle: Even if I had all the free parts and helpers like these boys do I would still use RockSim :p .




I didn't see the humor at first but now I do. Kinda sad though that Estes is so far behind the times.




Me too, duck and cover :rolleyes: My favorite way to fire back is to post a new design and say " All Semroc Parts" :D
I wish we would of answered the other question as well.

James Pierson
NAR# 77907
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And now for something completely different...

The new Estes Taser Twin, using an A2-0/A2-5 combination...

Not a bad combination, except for the little requirement of an 80" launch rod... :eek:

THAT was not an intended use! :D Craig. I like the way you are thinking!

The only thing I worry about in staging is the .06" nozzle in the upper stage. Not a very good target. One thing we were playing with in the 70's was "doping" the entrance on upper stage engines with BP paint. May have to look at that again.

Continued...

But, if you swap the A2-0 with an A10VS-0, the results are much nicer.

Launch rod now is back within the realm of sanity. It can use a 36" x 1/8" rod, and only requires 14" of that...

My pleasure, Carl. Unfortunately, the A2-0 doesn't have enough OOMPH to get cracking, but your A10VS-0 appears to be the ticket.

If we extend the engine tube up to the base of the sustainer engine, it might constrain more of the hot particles up toward that needle hole. An internal "stuffer tube" might constrict it some more, but there does get to be a 'point of no return'.

I take it a nozzle opening of 0.06" is a 'fixed figure', and anything larger just wouldn't allow enough pressure to build in the chamber, right?

What about painting something like the coating of an igniter up into the BP area? Something that would fire a bit hotter and more quickly?

Yeah!! Just mount 8 feet of 1/8" steel rod onto your launch pad, and you'll be good to go! :p

And don't worry, that much rod won't get whipped around - I promise... :chuckle:

(Kind of like fly fishing with rockets! :D Now quick! - Everyone into that blockhouse!!!)

MarkII

P.S. I saw your subsequent mod, Craig, but you know me - I couldn't resist... :rolleyes:

Yeah, the nozzle diameter is one of the most critical factors. If it is raised to .07", performance drops about 25% or so. If you lower it to .05", performance goes up (until the cato starts.) The A10 (A13?) will have about a .165" nozzle, but it is in the booster, not in the sustainer.

That is what I mean by "doping" the entrance.