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

[REK]

All of my free time has been consumed by more pressing matters. I will be able to get to this maybe during the weekend.

Up next.... the fin can!

I understand, looking forward to the fin can.


Composite Addict

 

[JimJarvis50]

I have been burned before with GPS units and really wanted to make sure I recover this rocket; especially since it is for a record attempt and my L3!

Hey, was just looking over the Tripoli forums today and I saw that some guy, Mat Orsak I think, set a new N record at Balls. N5800 to 63,818 I believe....sweet....and I think it was for his L3 no less. How's that for a coincidence? All I can say, A5tr0 An0n, is that when you get around to your flight, I hope it goes exactly as high as Mat's flight and that it is exactly as excellent as Mat's flight. That would really be something.

Jim

 

[patelldp]

Hey, was just looking over the Tripoli forums today and I saw that some guy, Mat Orsak I think, set a new N record at Balls. N5800 to 63,818 I believe....sweet....and I think it was for his L3 no less. How's that for a coincidence? All I can say, A5tr0 An0n, is that when you get around to your flight, I hope it goes exactly as high as Mat's flight and that it is exactly as excellent as Mat's flight. That would really be something.

Jim

They are one in the same, but I’m pretty sure you knew that.

 

[ksaves2]

Must have held up in spite of what some thought might be too small a chute for descent. Nearly 64k on a cert flight. Wow, that might not be touched for awhile.
Wonder if Mat fine tuned the throw weight for maximum alt. Kurt

 

[AeroAggie]

Wonder if Mat fine tuned the throw weight for maximum alt. Kurt

I don't believe he did. He said a few posts back that the aluminum coupler cost him a couple thousand feet, but was necessary for stability.

 

[REK]

Challenge accepted


Composite Addict

 

[A5tr0 An0n]

Been delayed in finishing this up - "I might delay, but time does not." So let me try and finish this.

So for the fincan I expanded on what USC's RPL and Ryan Sebastian came up with on their respected projects. That is a phenolic leading edge on the fin's to ultimately prevent delamination of the composite structure. This was a great learning experience - allbeit a long one. I had nothing to go on about this design except a few photos, at the time. I basically recreated the concept from a few pictures and it provided many challenges. I have lost a lot of the main details here about the fincan (such as dims), so I will keep it simple - feel free to PM me for more details.


Design




Fincan Tube
The fincan tube is made up from FWCF and it 1/8" wall. Who says you can't bond fins to a FW tube?! :lol:

Core
The fin core is made from 0.0625" thick G11 plate.

LE/TE
The edges are made from 0.20" thick phenolic plate. This is the maximum thickness of the fin.

Build Up
The core of the fin is built up with spread tow carbon fiber.

T2T
The fins were layered with a mixture of 2x2 twill and spread tow carbon fiber for tip to tip. 3.5 layers of t2t were done. That is 1 layer that esstentially reienforced the fillets and 3 layers that progressively went to full T2T.

Ablative
I used the same ablative formula that I came up with and tested on other projects. The abltive covered all of the exposed carbon fiber and went up to the phenolic edges; less the fincan tube. The ablative was taken down to be flush with the phenolic edges.






Cross section of the fin. Here you can see the G11 plate sandwhiched by the CF layers and the ablative.


Flow:

1. I started with the G11 plate and the phenolic plate. Once I had my overall rocket designed and had the masses of all the other componets, I set out to design my fin shape. Once the fins were designed I needed to cut the plates to spec. I had them CNC cut with a router. This resulted in three products - the fin core, leading edge, and trailing edge.
   
2. Once that was out of the way, I need to bond these two parts together. In order to do this, I needed to slot the leading and trailing edge to be able to slide them onto the G11 fin core. I slotted them with my mill then bonded them onto the fin core with a cotronics 4525.
   
3. Let em cure. Next step was to bevel the leading/trailing edges of the fins. I built a jig and went about beveling them on my mill. The beveling came out very nice.
   
   
   
   
4. Now I needed to build up the fin cores with carbon fiber. I layered them with spread tow carbon fiber because of its properties. I used cotronics 4461 for a low viscosity resin. The fins were vacuum bagged.
   
   
   
   
5. Time to bond these fins to the FWCF tube. I needed an alignment jig for this so I drew one up and had it CNC cut by a router from MDF board. The fins were held in place and so was the tube. I bonded them to the tube with cotronics 4525 - let em cure and then removed the fincan from the alignment jig.
   
   
   
   
6. Next came time for the T2T. I used my usaual method for t2t. Basically I make cutting templates in a CAD then print them out and laythem over the carbon cloth and cut away. I then layered the CF cloth onto the fincan and used cotronics 4461 for the low viscosity epoxy. The assembly was then vacuum bagged and left to cure. I did 2 fins at a time to allow for maximum control.
   
   
   
   
7. I mixed up the ablative and then applied it with the greatest tool known - a popsicle stick. Once it cured I took it down to the same thickness as the phenolic edges.
   
   
   
   
   
   

Note: For ALL surface prepping I used 60 grit sandpaper and roughed the parts to hell.

 

[ChrisAttebery]

Great project and nice write up.

 

[A5tr0 An0n]

Designed. Bought. Cut. G11 & phenolic plates that make up the form of the fin.



Stacked. Time to bond all the parts together.



Surface prepped and ready for BONDING.


Bonded with Cotronics 4525 resin. The two pairs of fins on the bottom are extra for testing.



This is the jig I came up with for beveling the fins. The washers allow me to secure the fins to the board - I had to make up the space underneath the G11 plate and the phenolic.



Bevel jig secured to table and then I set my distances and stops and move the end mill over the work.



Beveling of the leading edge in action.



Leading edges beveled. Now onto the trailing edges.



Slightly different jig made for the trailing edges.



Move along. Flip. Repeat.



Fin beveled. Came out pretty nice.



Moving on in the next post.

 

[Steve Shannon]

I’m glad I’ll get to see how you did the fin can.
Out of curiosity, what was the descent rate. We probably will establish a limit.

 

[A5tr0 An0n]

The fin core layup templates. Tape it to the cloth and then I simply cut them out with 'special,' sissors.



CF cut. G11 surface prepped. LE/TE taped. BONDING.



Laying down cloth while wetting it out with 4461.



Just throw it in the bag. Pulled a good vacuum.



Close up on the bag under vacuum.



Straight outta the bag. Need to sand the root - a little over lap.



Sandy.



All done. Came out pretty nice.



Moving on to the FWCF can. Cutting it down to spec on my horizontal bandsaw.



Heres the fin alignment jig - all assembled. Credit goes to USC's RPL for the design.



Fins slide in and then so does the can. Fins can slide up and down in their respected slots.



Applied 4525 and slide fins down onto the tube. Let em cure.



Ass shot.



Fins tacked on. Starting to look like a rocket's fincan.



All measured, taped up, and ready for fillets. Laying down fillets with 4525.



Fillets done. Came out nice - will sand them smooth. 4525 is a slight nuisance to sand.




Moving on to T2T and ablative next next.

 

[A5tr0 An0n]

I’m glad I’ll get to see how you did the fin can.
Out of curiosity, what was the descent rate. We probably will establish a limit.

Nice to hear Steve. It'll all be up soon. I will have to pull the data files for the exact rate - but it was somewhere north of 100ft/s.

Great project and nice write up.

Thank you very much Chris!

 

[A5tr0 An0n]

Hey, was just looking over the Tripoli forums today and I saw that some guy, Mat Orsak I think, set a new N record at Balls. N5800 to 63,818 I believe....sweet....and I think it was for his L3 no less. How's that for a coincidence? All I can say, A5tr0 An0n, is that when you get around to your flight, I hope it goes exactly as high as Mat's flight and that it is exactly as excellent as Mat's flight. That would really be something.

Jim

Thanks for the comment Jim! That is definitely something lol.

I understand, looking forward to the fin can.


Composite Addict

There you go buddy. The finishing touches coming soon.

 

[Steve Shannon]

Your build quality is exquisite.

 

[A5tr0 An0n]

The 'half,' layer of T2T.



Cut and then repeated four times.



All the 'half,' layers cut and ready to go.



The templates that I make in SW and then print out. This gets taped to the CF cloth and the shape is then cut out.



As you can see the T2T layers are slightly progressive. They taper up to the leading edge. So I lay them down and cut them then cut the template down to the next size and repeat.



Test fit - good to go.



Time to start cutting the T2T layers. First round ready to go. Then repeat, repeat, and repeat.



All done and ready for BONDING.



CF laid, wetted, and peel ply applied. Ready to go in the bag.



In the bag. Had an issue with vacuum and didn't reach my target. Still pulled enough - but meh.



Stright outta the bag. Not much to neaten up. Came out very nice.



Sandy. Preppy. Taped. Ready for ablative.


Ablative applied and then left to cure. Will have to take it down to match the phenolic - that ought to be fun.

 

[A5tr0 An0n]

Went from no posts in awhile to quite a few long stringed ones. I know some can get lost in the noise so here is a contents directory.

Fincan Design & Workflow:
https://www.rocketryforum.com/showt...osite-N5800-Flying-Case&p=1774661#post1774661


Fincan Structure Cutting, Constituent's Bonding, Beveling Jig, & Beveling:
https://www.rocketryforum.com/showt...osite-N5800-Flying-Case&p=1774683#post1774683


Fincan Core Build Up, Fin Alignment, Tack On, & Fillets:
https://www.rocketryforum.com/showt...osite-N5800-Flying-Case&p=1774707#post1774707


Fincan T2T Prep./Cutting, Vacuuming, & Ablative:
https://www.rocketryforum.com/showt...osite-N5800-Flying-Case&p=1774730#post1774730

 

[grouch]

So much sickness I just wet myself. Very nice work man.


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[REK]

Why dont I get notified no more what gives? Man that must have hurt painting over that wicked spread tow material man. Seeing the roll from composite envisions and the no fraying when cutting. I can only assume it was a textreme flat tow carbon.

Thanks for the update, your work is amazing.


Composite Addict

 

[HyperSonic]

When I seen this fabric on this thread, I just have to get some! Do my T2T with it. Haven't picked out which textreme fabric to use, maybe around 4 to 6 oz. Very Very impressive work! My fins are jealous!!

 

[REK]

When I seen this fabric on this thread, I just have to get some! Do my T2T with it. Haven't picked out which textreme fabric to use, maybe around 4 to 6 oz. Very Very impressive work! My fins are jealous!!

I recommend 4oz. The more layers the better.


Composite Addict

 

[BDB]

Great work!!!! Could you elaborate on the “special” scissors you used to cut the CF? There’s no way I could cut that accurately for a tip-to-tip layup with no overhang.


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[markkoelsch]

Great work!!!! Could you elaborate on the “special” scissors you used to cut the CF? There’s no way I could cut that accurately for a tip-to-tip layup with no overhang.


Sent from my iPhone using Rocketry Forum

I would recommend Kevlar shears. They are special scissors that can easily cut Kevlar. I found a pair on Amazon for $30 or so. If I think of it later, I will run downstairs and get make and model.


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[markkoelsch]

In basement working on things. The Kevlar shears I purchased are Clauss 8” bent handle, model 18425. Reasonable price and cut Kevlar, carbon fiber, and glass with ease.


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[A5tr0 An0n]

Thank you for the kind replies Steve, Grouch, Sinful, HyperSonic, & BDB.

 

[A5tr0 An0n]

Why dont I get notified no more what gives? Man that must have hurt painting over that wicked spread tow material man. Seeing the roll from composite envisions and the no fraying when cutting. I can only assume it was a textreme flat tow carbon.

Thanks for the update, your work is amazing.


Composite Addict

When I seen this fabric on this thread, I just have to get some! Do my T2T with it. Haven't picked out which textreme fabric to use, maybe around 4 to 6 oz. Very Very impressive work! My fins are jealous!!

I used Textreme 1014. Thats the IM 152GSM Spread Tow CF.

 

[A5tr0 An0n]

Great work!!!! Could you elaborate on the “special” scissors you used to cut the CF? There’s no way I could cut that accurately for a tip-to-tip layup with no overhang.


Sent from my iPhone using Rocketry Forum

Lol sure. I was being partially sarcastic about the "special," scissors. The scissors that I use are just $30 fabric scissors. I treat them as such. Only use them for composite work and keep them in their included sheath. Everybody develops their own way of cutting - I have found that I can cut with very minial fraying & good acuracy with my current setup.

 

[A5tr0 An0n]

Electronics/Recovery/Deployment

I ended up using a BRB 70cm 100mw, AltusMetrum TeleMega, and a AIM XTRA 2.0 for tracking and flight computers.

I had the TeleMega setup as the primary deployment and the AIM as the secondary deployment. There was a delay between when both the flight computers are set to fire the respected charges. Both computers were only set/wired for apogee deployment. This rocket uses a single deployment method utilizing only one parachute in place of the standard dual deploy method utilizing both a drouge and main parachute. This is done to remove the break in the airframe, simplify the recovery design, increase efficency, decreases the potential splash down radius, etc.

Standard 4F BP charges & JTEC style ematches were used. The BP was sealed inside a threaded nipple tube designed for plumbers. One end is epoxied and cured (JB Quickweld), BP poured & ignighter in place, other end sealed, and ready for business. I used 2 charges (each with redundant ematches) for this flight.

I used 1 inch kevlar for the harness, no Quicklinks or swivels were used (except one that was already installed from a previous flight). They are not needed. Used a 15" or 18" (can't remember which it is) classic elliptical parachute made by fruity chutes. It has a Cd of ~1.5-1.6. Bring em down.



Thanks goes out to Mitch & Jerry for the help with transportation and use of their tower!!!




Cardboard box, Nose Cone, and rocket parts as your carry on?!



T-Minus 1 day. No time to paint the can or cone... otherwise they would have both been painted white.




The obligatory simulation graphs:
I normally measure the mass for all components throughout the build and input them into my sims to minimize error. I actually got close with my mass measurements but did not get the final weight. I would guess it was within a 1lb of actual weight. Pretty big range for such a light rocket - I know. Sorry, no scales in the desert and busy schedule.



OR altitude is spitting out roughly 68,750'.



RAS II is spitting out roughly 70,500'.



Max. stability @ max. Mach is ~0.875.




Oh and if you're curious - ROCKSIM says its going ~35,000 ft....

 

[Reinhard]

Lol sure. I was being partially sarcastic about the "special," scissors. The scissors that I use are just $30 fabric scissors. I treat them as such. Only use them for composite work and keep them in their included sheath. Everybody develops their own way of cutting - I have found that I can cut with very minial fraying & good acuracy with my current setup.

Rotary cutters (think pizza cutter) work well for carbon and glass fibers. Kevlar would be problematic with them, I believe.

Reinhard

 

[rharshberger]

Rotary cutters (think pizza cutter) work well for carbon and glass fibers. Kevlar would be problematic with them, I believe.

Reinhard

I use a Fiskars Rotary cutter for cutting FG and CF it works great with less pulling of tows/fibers than scissor cutting. I agree that it probably wouldnt work well for kevlar.

 

[A5tr0 An0n]

Rotary cutters (think pizza cutter) work well for carbon and glass fibers. Kevlar would be problematic with them, I believe.

Reinhard

Yeah, I've used them before - have a buddy that prefers them also. I still prefer the shears as it lets me move and get underneath the fabric and cut without it being flush on the table. All around I feel that I get better control with them. The rotary cutters do pull less on the fibers - however practice makes better lol.