98mm N5800 MD rocket for BALLS

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It is a project from last year. We told the TRA Class 3 Committee not to approve any over 30'/sec in the future.
I had heard from a TRA BoD member that recently saw it they were changing to a parachute.
 
We launched MANY O10,000's minimum diameter and never had a stuctural issue with the welded Al fin cans. Yea they are heavier but the rocket goes higher in one piece. we hit nearly M4 with a 2 stage with no fin isssue.

Thunderbolt?
 
It looks like you are going for 4 fins (unless 1 is a spare) instead of 3, so the rocket will incur a drag penalty with the extra fin.

Is the rationale primarily for stability, or is it for another reason?

Greg
 
You could be Robert von Braun Goddard and still be wrong about the use of steel in rockets. In this case you are not, and are, respectively.

Steel has better thermo-mechanical properties than CF under all but heroic layups or RCC. It is denser, but can be made far thinner than CF structures (these fins an ideal example.) If 1/8th inch steel can recreate what these 1/2 inch fins can do, suddenly the density is less of a problem. Furthermore, thinner fins compensate for extra mass by reducing drag. And on a nearly hypersonic rocket, getting thin fins is well worth hundreds or thousands of extra grams.

The argument ultimately comes down to this: composites are struggling to survive these kinds of flights. If going to steel helps a rocket survive the flight, steel is the superior choice. This OP is working on something else so I completely understand his use of composites as a challenge. But the statement that composites are better than metals, even if you set aside inconel, titanium, beryllium, etc., is very hard to support. Aluminum has been the go-to material for high performance rockets in this hobby for a long time... more than 20 years. There is a reason for that. Composites may replace metal in that lower end, but in the mach 4+ realm? I seriously doubt it.

Let's break it down into two parts: Metals are better for a significant range of hobby and amateur rockets, particularly those that achieve very high mach numbers in the lower atmosphere. And since composites are a huge part of the core of the HPR hobby, it is great that people are pushing the limits of composites to see how far they can go. I bet they can handle an N5800 when done right, and I get a good feeling about this project. Best of luck and post more pics!

New Ocean,

Glad to see you've ignored butalane's relevant question about your own personal experience with flying high performance birds. Also glad to see you've engaged in a healthy dose of internet hypocrisy, calling butalane an "anonymous snob" (what are you?) Finally, good work calling out people in the aerospace industry for being wrong about casing materials they work with every day (hands on work, not just internet reading) and people far more accomplished in the hobby realm than yourself.

Since June, you've been preaching the N5800 as the greatest rocket motor ever created. This alone shows your a.) ignorance and b.) lack of experience in propellant and motor design outside of the hobby rocketry realm. Yes, the N5800 blows all other aluminum-cased hobby motors out of the water. Why? Because it begins to approach and take advantage of basic properties of all high performance propellants in the aerospace industry that are largely ignored in most hobby motors due to casing material constraints and the greater appreciation in the hobby market for effects motors as opposed to highest-possible ISP.

In June, you challenged me to make a more efficient motor than the N5800. I did so, in the same sized case, and flew it at LDRS. I'd give you data, but the flight scrambled the accelerometer data beyond recognition. So, I've made another, bigger motor to fly at Balls (see you there I expect) with a higher-g-capable accelerometer along for the ride. I'll be sure to post back and let you know how it works.

You state that composites are "struggling" to handle these kinds of flights. butalane is talking about the use of steel and composites as motor hardware, first off. Second, yes, aluminum has been the go-to choice in the HOBBY realm for over 20 years because it's cheap, easy to machine, and does just fine for upper-end hobby flights (my project at Balls has an aluminum fincan). When composites are applied beyond rudimentary amateur setups (cheap curing oven and vac bag setup, at best) they are superior in use and functionality. Just like the N5800, aluminum it does great for it's application. But that doesn't mean that there's not a better solution.

-Your fellow anonymous snob
 
boxing_smiley.gif

In corner #1 we have Butalane/prophecy/MClark and in corner #2 we have...

Wait, I don't care who is in corner #2, my bet is on corner #1

:pop:
 
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New Ocean,

Glad to see you've ignored butalane's relevant question about your own personal experience with flying high performance birds. Also glad to see you've engaged in a healthy dose of internet hypocrisy, calling butalane an "anonymous snob" (what are you?) Finally, good work calling out people in the aerospace industry for being wrong about casing materials they work with every day (hands on work, not just internet reading) and people far more accomplished in the hobby realm than yourself.

I didnt ignore his question, I rejected it as irrelevant and rude. I removed the snob comment not because of you, but because I spoke to him personally and realized that it was too harsh and it is inevitable that people would challenge what I say not on facts or merits, but on personal attacks. That is the way of life in online forums. For example, I could ask why you, with 35 posts, are qualified to talk about this. Would that be fair? I think not.

Since June, you've been preaching the N5800 as the greatest rocket motor ever created. This alone shows your a.) ignorance and b.) lack of experience in propellant and motor design outside of the hobby rocketry realm. Yes, the N5800 blows all other aluminum-cased hobby motors out of the water. Why? Because it begins to approach and take advantage of basic properties of all high performance propellants in the aerospace industry that are largely ignored in most hobby motors due to casing material constraints and the greater appreciation in the hobby market for effects motors as opposed to highest-possible ISP.

It is the greatest motor in the hobby if by great you mean the most effective at high performance flight within the impulse limits of the hobby. Obviously it is only a competition between it and other N motors, and among N motors, it wins. If there could be a slower burning version, that version would win out. In my opinion, the greatest motor in the hobby is the N10,000 because... why the f!@$! not? It is a mean motor and that I how I likes them. Honorable mention for the N1100 too. Three flavors of a really great thing. But even then, the N5800 stands out ahead of the pack in total impulse and vacuum delta v potential.... and I mean far ahead of the pack.

If you think I am obsessed with this one motor, you should see me talk about the O 10,000.

Also, and this keeps coming up... the ISP in hobby motors is not much worse than pro motors. It is the mass fraction that we lack. Big difference, and the N5800 wins out in performance because through several means (including a good but not exceptional ISP) it achieves the best mass fraction in a large motor with a perfect aerodynamic length to width ratio.

In June, you challenged me to make a more efficient motor than the N5800. I did so, in the same sized case, and flew it at LDRS. I'd give you data, but the flight scrambled the accelerometer data beyond recognition. So, I've made another, bigger motor to fly at Balls (see you there I expect) with a higher-g-capable accelerometer along for the ride. I'll be sure to post back and let you know how it works.

I am sorry that was still smouldering in the back of your mind. I would love to hear more about your rocket and motor, as this is my fav. hobby so there is no such thing as too many rocket pics or data sets. I can't know what you have not proven. Tell us more about your motor now, no need to show the data even. Just describe it for us.

You state that composites are "struggling" to handle these kinds of flights. butalane is talking about the use of steel and composites as motor hardware, first off. Second, yes, aluminum has been the go-to choice in the HOBBY realm for over 20 years because it's cheap, easy to machine, and does just fine for upper-end hobby flights (my project at Balls has an aluminum fincan). When composites are applied beyond rudimentary amateur setups (cheap curing oven and vac bag setup, at best) they are superior in use and functionality. Just like the N5800, aluminum it does great for it's application. But that doesn't mean that there's not a better solution.

I would not put words in his mouth, but the impression that I get is he is talking about rocket airframes and less about motor casing. I sure have been... since there is no choice in motor casing here. For solid rocket motor casings, composites are often better. That is why they have been used since the 1960s in pro. motors. That says nothing about high performance rockets and airframes. If you look to the professional rockets, metal is still king overall. I have no vested interest in the metal lobby. I only care about rockets surviving their flight. It does behoove me to ask other to explain how composites are better than metal. I still have not seen that answer.

In corner #1 we have Butalane/prophecy/MClark and in corner #2 we have...

Wait, I don't care who is in corner #2, my bet is on corner #1

It is not like that at all, please be nice.
 
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Personal experience is always relevant. It's rude to give advice as fact when you haven't actually done it.

Facts trump personal experience. I respect experience, but only accept facts. Which reminds me, have you any information on the debate over metal vs composite airframes, particularly fins and nosecones, but also airframes proper, in the regime between sea level and 50,000 feet and top speeds of mach 4 to 6?
 
Facts trump personal experience.

Facts trump REAL WORLD, EMPIRICAL data, are you serious??? Say bye bye to the limited credibility you may have had up to this point with that statement.

This was on track to be a rather kick ass build thread, can we get back to it please?



Justin
 
Facts trump REAL WORLD, EMPIRICAL data, are you serious???


Facts are real world empirical data. Yes I am serious.

In my post above I said facts trump experience. Please read the first four words in a post before replying.

I agree we should get back to the topic here. So what input do you have on building rockets to survive 0 to 50,000 feet at mach 4 - 6?
 
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have you any information on the debate over metal vs composite airframes, particularly fins and nosecones, but also airframes proper, in the regime between sea level and 50,000 feet and top speeds of mach 4 to 6?
We did it once with an all-composite airframe, nose cone, and fins, as has been pointed out earlier in this thread (I think - there are so many damn N5800 threads now I can't keep track of them all). Chris looks like he's got a good handle on the situation, too. Can we move on?
 
Facts are real world empirical data. Yes I am serious.

In my post above I said facts trump experience. Please read the first four words in a post before replying.

I agree we should get back to the topic here. So what input do you have on building rockets to survive 0 to 50,000 feet at mach 4 - 6?

New Ocean,

Your stance -- "facts trump personal experience, so I only accept facts as valid" is a convenient way of qualifying yourself, with no personal experience in this realm, clearly (otherwise you'd have spoken up by now instead of playing defense), to participate in a conversation in which you probably shouldn't be participating.

I'm sure you could find a personal attack on me, but post count actually wouldn't be valid...perhaps I've spent less time armchair refereeing, trying to get others to believe that I know what I'm talking about by talking out of my @$$ on an online hobby rocketry forum, and more time making and flying high performance airframes and motors.

Your statement that experience has nothing to do with credibility is shortsighted and defies basic logic of how things work. I learned to drive from someone who themselves had a license; 99% of sports coaches, from the high school level to the professional level, are former players; otherwise, like you, they'd have zero credibility.

It's pretty incredible that you took butalane's and my line "so what experience do you have flying high performance rockets?" and changed it to suit your position "so what INPUT do you have?"

I have personal flying experience with both rfjustin and butalane as well as many others in this thread, and can guarantee that you have little wiggle room to call them out for rocketry ineptitude without being indulgently hypocritical.
 
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Chris:
What are your plans for shear pins?

The plan is not to use any for the apogee deployment, but the main container will be shear pinned shut. The whole recovery system is somewhat experimental, so I'm still working out the details though.


Also, New Ocean et al...
This was interesting at first, but this argument is getting somewhat tiresome. Could you start a different thread or take it to PMs or something if you would like to continue arguing? Thanks...
 
I would go with a carbon fiber airframe, I would go with an AL fincan, with carbon fiber overlay. It would be a non-refundable journey....(delamination probably...)
 
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New Ocean, Justin is right. You have to have experience to have the real world empirical data... and those are not facts.

Okay Clay, what nosecone is the best? How far is Mars? What is the melting point of steel?

Unless you directly experienced these things, you cannot have empirical data on them?
 
Your stance -- "facts trump personal experience, so I only accept facts as valid" is a convenient way of qualifying yourself, with no personal experience in this realm, clearly (otherwise you'd have spoken up by now instead of playing defense), to participate in a conversation in which you probably shouldn't be participating.

And yet after all this time, you have contributed nothing to the discussion. Your sole role here is to complain that I am not experienced enough to talk in this thread, and to claim that you built some kind of uber N motor, superior to the N5800 but the data got frazzled during the flight.

If you got offended in another thread where I called your EX motor into question, I am sorry. But your experience does not impress me in the least. This is a forum where ideas stand on their own merits. Ignore the names and re-read this thread with an open mind.

You remind me of another person who recently attacked a person who was "just a kid" and clearly could have no input on rockets.
 
CJL, you are a brave man with those fins.... I think thats in the top 5 coolest things ive seen on trf.
 
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Also, New Ocean et al...
This was interesting at first, but this argument is getting somewhat tiresome. Could you start a different thread or take it to PMs or something if you would like to continue arguing? Thanks...

Anybody see this????
 
End the derail over who's data is better. Back to topic please.

Thanks
 
So the electronics are being started today - after a bit of test fitting, I discovered that it will be a slightly tighter fit than I had initially hoped. It looks like it will work fine, but I can't proceed without a Telemetrum (so I can fit it properly), so I'm heading off to Apogee now to pick one up. Currently, the plan is to fly a Beeline GPS (high power 100mW 70cm version), two Raven's (a 70G and a 250G, both with Adrian's high altitude firmware), and a Telemetrum, so I should have redundant deployment and redundant tracking, as well as tons of data. I'm still undecided about whether one of the Ravens will just be along for the ride, leaving the other Raven and the TM as the deployment altimeters, or whether I'll use both Ravens for deployment, with the TM and Beeline along purely for data and tracking. I'm hoping to get the electronics mounted, at least in a rudimentary fashion tonight, so I'll have pics if that happens. Tomorrow though, I leave to take my sister off to college, and I won't be back until Monday night, so if I don't get as far as I'd like tonight, there won't be any more updates until Monday or Tuesday (I'll have internet though, so I'll still be able to answer questions or discuss the design).
 
I think we need a picture of CJL's progress. Pictures make everything better in forums.
 
Can one of you please be humble enough to be the first one to let it go and let the other guy have the last word?

It'd be really nice if we can get back to a constructive discussion about what Chris is up to.

-Kevin
 
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