[L3] Composite N5800 Flying Case, ~67kft MSL, M3.5

Back Story

So here's another go at this. I first set out to get my Level 3 on the notorious N5800 back in 2014 and I ended up scrubbing the flight out on the playa in Black Rock. I was not happy with the way that the chips had fallen, so I decided to let that rocket die and start anew. I did however refurbish that vehicle and flew it on an ex motor that can be found here -> https://www.rocketryforum.com/showthread.php?124218-Post-Flight-1-Weekend-and-65-000Ns&p=1439465#post1439465

So in between shifts on the long drive back from Black Rock (approximately 30 hours), I designed the new Level 3 rocket for the N5800. On the first scrubbed rocket, I used more conservative techniques that I felt would increase the likelihood of suriviabilty. Such techniques included such things as double walled airframe, minimum diameter airframe, double walled nose cone, thick fins, heavy rocket, blah blah, etc. Not to mention, I used Nic's idea of metal brackets underneath the fillets to attach the fins to the airframe and metal leading edges. That was one of the defining moments of my build that created the unfavorable thoughts in my mind about this rocket. It also didn't exactly turn out as planned lol; I am at heart a composites guy and really wanted to do a true no metal-all composites flight on this motor. I would soon (only a couple of years!) get my chance to give it another go with an all composite design.

So with the new design being conceived on the road home from black rock in 2014, I set out to make major changes to the design and went back to my foundations and knowledge of composites. I also liked the idea that I could potentially be the first one to survive the N5800 in a MD/Sub-MD configuration without the use of any added metal (less NC tip). To my knowledge (at this point in time) there have been 20+ attempts at flying the N5800 and only 3 successful flights. All of these rockets used metal, when it came to their fin designs. Gerald Meux and Mike Passaretti both had very successful flights with metal fin cans. Nic Lottering also did; using metal fins sandwiched between carbon with metal leading edges and metal brackets, securing them to them airframe. Many rocketeers have tried using composites with all of them failing. The thought of being first was kind of cool and so was the idea of having this rocket be my level 3 project. To my knowledge the only other person to get their L3 with a high altitude and multiple Mach number breaking flight is Jim Jarvis. He flew to ~34kft and M2.5, if I remember correctly. So with some arbitrary goals set out, I had a very simple design philosophy and a plan.

The execution of this plan, proved to take a couple of years as building started and stopped multiple times due to life getting in the way. The following will be my story of building this project from then to now. The road is always a very scenic one.

Hope everyone can learn from my project whether it is what to do or what not to do. I make no claims that what I do is the best way or the right way lol.

More to come shortly.

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Looks like we are on very similar paths to our L3. I will be watching your build thread with an invested interest.

dhbarr said:

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Isn't that this hobby in general?

op:

This will be very interesting to read up on. Much success to you.

I'll also throw out that there was just an L3 cert from a fellow HARA member that broke 30k' and Mach 3 at Airfest.
Single 48" length fiberglass tube, High% M motor, cable cutter dual deploy, Engine block enamel on the nose and fins (bare tube).

Is this that 29k ft N5800 from Balls last weekend? That sure was a mean 29k

Nytrunner said:

This will be very interesting to read up on. Much success to you.

I'll also throw out that there was just an L3 cert from a fellow HARA member that broke 30k' and Mach 3 at Airfest.
Single 48" length fiberglass tube, High% M motor, cable cutter dual deploy, Engine block enamel on the nose and fins (bare tube).

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Thank you very much! Oh, it is nice to see someone pushing their limits for the L3, as opposed to the traditional 'low and slow,' method.

slaak said:

Is this that 29k ft N5800 from Balls last weekend? That sure was a mean 29k

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No, it is not. It would be interesting to hear more about that flight though.

Nytrunner said:

This will be very interesting to read up on. Much success to you.

I'll also throw out that there was just an L3 cert from a fellow HARA member that broke 30k' and Mach 3 at Airfest.
Single 48" length fiberglass tube, High% M motor, cable cutter dual deploy, Engine block enamel on the nose and fins (bare tube).

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Video that I captured of that flight:

[video=youtube;KQ7bkjyp8Og]https://www.youtube.com/watch?v=KQ7bkjyp8Og[/video]

Note how high the rocket gets before you hear the first sound from the motor. :surprised:

I am subscribed. Hoping for great success. Oh and I too will be doing this for my level 3 one day .


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If I ever get to L3 candidacy, I definitely won't be going for any records lol. Once I have the cert in the bag, then I'll open up the design space (fins? Who needs fins!?)


What sort of coating or outer epoxy are you planning for your composites?

Thank you everyone!

Nytrunner said:

If I ever get to L3 candidacy, I definitely won't be going for any records lol. Once I have the cert in the bag, then I'll open up the design space (fins? Who needs fins!?)


What sort of coating or outer epoxy are you planning for your composites?

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I use 'industrial,' grade high temp (500F-600F) laminating and structural epoxy for all composite parts. Whether I am laminating or bonding parts that's what I use. A long time ago I use to coat the leading edges of the fins with epoxy to help prevent delamination. I haven't done that in years and will not be doing that on this project.

A5tr0 An0n said:

Thank you everyone

I use 'industrial,' grade high temp (500F-600F) laminating and structural epoxy for all composite parts. Whether I am laminating or bonding parts that's what I use. A long time ago I use to coat the leading edges of the fins with epoxy to help prevent delamination. I haven't done that in years and will not be doing that on this project.

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Thanks!

Are you overlaying a layer around the leading edge, or leaving the layered edges "bare"?

Nytrunner said:

Thanks!

Are you overlaying a layer around the leading edge, or leaving the layered edges "bare"?

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No to the overlaying layer around the edges and technically no to the layered edges remaining bare. They essentially are bare, however there is no exposed carbon (layered or not) on the leading edges. So yes the leading edges are 'bare,' but they are not bare t2t carbon. If that makes any sense lol.

A5tr0 An0n said:

No to the overlaying layer around the edges and technically no to the layered edges remaining bare. They essentially are bare, however there is no exposed carbon (layered or not) on the leading edges. So yes the leading edges are 'bare,' but they are not bare t2t carbon. If that makes any sense lol.

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I think I follow. There's natural epoxy matrix protecting edges left by your layup I take it?

Nose Cone Meets Motor: A Design Overview

So back in 2014, after scrubbing the previous N5800 project, I felt that I did a lot of things that just were not in my nature. I used overly conservative design parameters and utilized certain materials that didn't sit right. While I conceived the design, I kept thinking of a simple question... should I eliminate the additional composite airframe? This wasn't new to me; in the past I had used the pressure vessel as the airframe. I wanted to utilize a slightly more optimum design, this is a L3 after all!. So it was settled; I decided that I wanted to use a sub-minimum diameter approach known as a 'flying case.' With the elimination of the additional airframe, that meant that I needed to consider using an upper airframe for either the payload or recovery bays. After a couple of seconds of thought, I decided that the upper airframe was not needed!
Hence, nosecone meets motor case! That's right, I decided that I would design a coupler based on previous projects, that would allow me to connect the nosecone directly to the top of the N5800 motor. Now we're getting somewhere...

The nosecone to solid rocket motor coupler, would also serve as a payload bay, housing the electronics. The space between the payload and the tip of the nosecone would serve as the recovery bay, housing all attachment points, harnesses, and parachutes. This helped minimize components and simplify the design slightly, or at least in my mind. With most of the rocket roughly thought out, all that was left was the fincan. Here is were things started to go off my normal beaten path. After feeling the detrimental results of time during the initial project, I decided that I want to make this project a blend between efficiency and optimization. There is a point where the investment is no longer worth the return, and I had to figure out where that point was. At this moment in my life, there are many things consuming my time and I cannot go all out as I once used to. For me, the trade off for slightly less performance but a quicker/easier build time, lived within the nosecone & fincan. For the last project I had made a Filament Wound Fiberglass Nosecone (FWFG) and a Filament Wound Carbon Fiber (FWCF) airframe, both using high temperature laminating resins. My problem with these components was that they were both 'double walled,' meaning they were very heavy! The opportunity cost of reusing components was the loss in maximum altitude and velocity that this vehicle could achieve. Seeing as I was once bitten and twice shy, I determined that the marginal cost was greater than the marginal benefit and I chose to not remake these components.

With total optimization out the window, I cleared my mind and accepted that I was yet again not going to max this project out... but it would fly soon! Or so I thought lol, ended up taking a couple of years. With my thoughts in order it was time to start the finessing of the design process; I embarked on a mission to cross all the 't's' and dot all the 'i's'. I will save you from all the boring stuff now but we will get back to the design in more detail in the following posts. Below you can find the sketch ups I did of the design.









Some of these numbers might change over the progression of this project. So if you find a different value over time, then assume that the last reported value is the most relevant.

Great looking project Matt. Following.

BTW: A couple of your pictures on Flickr are private so we can't click on them and see a full res version.

ChrisAttebery said:

Great looking project Matt. Following.

BTW: A couple of your pictures on Flickr are private so we can't click on them and see a full res version.

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Thank you very much!

Oh, sorry about that! Should be fixed now; if you have any issues just let me know. I'll have more to post soon.

A5tr0 An0n said:

No, it is not. It would be interesting to hear more about that flight though.

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I never saw the rocket up close so I don't know much about it other than what I was told from a friend of the owner. From what I was told someone had a pretty similar idea of using an N5800 for the cert flight in a MD rocket. I don't think they had any lower airframe and had bonded their composite fins directly to the motor casing. I called it the 29k ft N5800 though because I guess when they where applying for their high altitude waiver whomever was in charge of approval told them their rocket was only going to go to 29k so whey wouldn't be required to get said waiver (it was only needed on flight over 50k). Needless to say the rocket went much more than 29k and the friend told me he successfully got his level 3 and set the N record flying somewhere in the upper 60's if I remember correctly.
Not sure if destroying your waiver disqualifies the record though...

I don't know whether violating the limits of a COA disqualifies an altitude record, but it certainly does disqualify a certification attempt.
For clarification, although we (Tripoli) require Class 2 flights that are expected to exceed 50k to be reviewed by the Class 3 Committee, they don't require a separate COA (Certificate of Authorization). An N or O motor in a Level 3 certification attempt is Class 2.


Steve Shannon

Steve Shannon said:

I don't know whether violating the limits of a COA disqualifies an altitude record, but it certainly does disqualify a certification attempt.
For clarification, although we (Tripoli) require Class 2 flights that are expected to exceed 50k to be reviewed by the Class 3 Committee, they don't require a separate COA (Certificate of Authorization). An N or O motor in a Level 3 certification attempt is Class 2.


Steve Shannon

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What I know about the flight is all second hand so I don't know how accurate is it, but I believe they submitted their flight to the class 3 Committee because they expected to go above 50k but where told it wouldn't so they weren't required to continue with submitting their flight as class 3. No idea how that whole system works and if that is possible or not. Would accidentally (or not?) going above the 50k limit disqualify the cert if it had been submitted?

Take what I said as hearsay no idea on the level of truth, I just asked someone around the campfire on how a min diameter N5800 only went 29k and that's more or less what I was told.

Also sorry for going off topic on your build thread, this Rocket looks awesome and I cant wait to see more about it.

slaak said:

What I know about the flight is all second hand so I don't know how accurate is it, but I believe they submitted their flight to the class 3 Committee because they expected to go above 50k but where told it wouldn't so they weren't required to continue with submitting their flight as class 3. No idea how that whole system works and if that is possible or not. Would accidentally (or not?) going above the 50k limit disqualify the cert if it had been submitted?

Take what I said as hearsay no idea on the level of truth, I just asked someone around the campfire on how a min diameter N5800 only went 29k and that's more or less what I was told.

Also sorry for going off topic on your build thread, this Rocket looks awesome and I cant wait to see more about it.

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At the risk of going further off topic: Class 2 flights can all be flown under a single COA (waiver) that covers the entire event. That waiver is not limited to 50,000 feet. The requirement to have flights that are anticipated to exceed 50k be reviewed by the Class 3 Committee is a service to the flyer and is not related to any particular FAA requirement, but rather is done to simply add a margin of oversight to help prevent possible problems.
If an event has a Class 2 COA (waiver) that exceeds 60k and a rocket was expected to fly to 29k and actually flew to 60k, that is not a violation of the waiver. It's difficult to believe that the C3C would miss their simulation by that much but that's a whole other subject. Under the circumstances you've described I don't believe that a cert would be withheld.
I'm also sorry for the thread drift.


Steve Shannon

lol, nice. Off topic, on topic, who cares? lol. I think its very interesting myself.

It's difficult to believe that the C3C would miss their simulation by that much but that's a whole other subject.

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Honestly, these days nothing really surprising me anymore. For example, I just found out a really good college (second largest in the US) is on probation and might loose their accreditation.

I have a questions about the design. The nose one slips over the forward part of the the casing. The electronics bay attaches to the motor forward closure via the threaded portion of the forward closure. Am I correct thus far? So, at apogee you pop a charge to blow the nosecone off...is there a drogue? The single chute states single deploy- are you using something to restrain the chute- if so, what device?


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markkoelsch said:

I have a questions about the design. The nose one slips over the forward part of the the casing. The electronics bay attaches to the motor forward closure via the threaded portion of the forward closure. Am I correct thus far? So, at apogee you pop a charge to blow the nosecone off...is there a drogue? The single chute states single deploy- are you using something to restrain the chute- if so, what device?


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Yes, the nosecone slips over the coupler/payload bay that attaches to the forward end of the motor case. The attachment is a little more secure than it just being threaded on top, but sure. At apogee the nosecone separates and the only parachute comes out. I am using single deploy; pop out the only chute at apogee with no restraint. Thank you for the questions Mark!

A5tr0 An0n said:

Yes, the nosecone slips over the coupler/payload bay that attaches to the forward end of the motor case. The attachment is a little more secure than it just being threaded on top, but sure. At apogee the nosecone separates and the only parachute comes out. I am using single deploy; pop out the only chute at apogee with no restraint. Thank you for the questions Mark!

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Really looking forward to the rest of this thread, Mat.

Also, what sort of parachute are you looking to use? X-form?

Well, you've gotten this far, so as long as you're confident in your trackers and prepared for a long walk/drive, single deployment isn't specifically disallowed.

I assume your TAP/L3CCs have signed off?

A5tr0 An0n said:

Yes, the nosecone slips over the coupler/payload bay that attaches to the forward end of the motor case. The attachment is a little more secure than it just being threaded on top, but sure. At apogee the nosecone separates and the only parachute comes out. I am using single deploy; pop out the only chute at apogee with no restraint. Thank you for the questions Mark!

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Wow, that should be quite the hike. Bring it down fast, but not so fast as to cause damage that would invalidate the cert. Also, if you land outside the waiver cylinder that is a no no.

As said previously- you best be very certain of your tracking system. Might I suggest an rdf beacon as well as the gps. I have seen several gps flights lose lock and not regain lock hence being less than useful.


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littlemisterbig said:

Really looking forward to the rest of this thread, Mat.

Also, what sort of parachute are you looking to use? X-form?

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Thanks! The parachute is a 18" Elliptical Parachute with a Cd of about 1.6.