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Mach 3.5 Loki L Altitude Record Attempt Build

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Nytrunner

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What's your plan for blending the edges and filling in the fin pocket corner gaps just ahead of the inlays?
 

watheyak

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What's your plan for blending the edges and filling in the fin pocket corner gaps just ahead of the inlays?
There are some slight gaps around the inlays, especially at the trailing edges. Those will be filled with Cotronics 4525.

The rest of the fillets will be JB Weld, or possibly high temp Hysol, sculpted to a leading and training edge fillet shape.
 

BDB

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The last nosecone had a phenolic tip. The person who made that tip is busy putting his superb skills to much better use making super secret aerospace parts.

I had the idea to print the tip on my resin printer from high temp resin. The high temp SLA resins are usually meant for injection molds for rapid prototyping, but so far the parts I've made seem like it's pretty tough stuff. I had a tip print that didn't turn out so hot, so I'm going to abuse it a bit to get a better feel for how it'll hold up.

The first resin I tried is Siraya Sculpt. It's good to ~350°F and a nice gray color.

View attachment 443312

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I'm printing some Siraya Sculpt right now. It's exciting to see SLA printing getting more popular for applications like this.
 

watheyak

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Also, once the fillets are done, the whole fin can will be sanded smooth and polished. No paint. No ablative.

Tomorrow morning I leave for work for eight days. I'll pick up the regularly scheduled programming when I get back!
 

watheyak

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Not much building going on these set of days off, but I did fly at the club's monthly launch and test out the av-bay and deployment set-up in a similar rocket.

The rocket itself was a minimum diameter using a single airframe break and cable cutter. And quick. There's probably 2 hours of total labor into it. AMW parts, Dragonplate fins cut by Nat at Upscale CNC and beveled by Mike at MAC. Flew on a Loki K350 moonburner. All around team effort! Great flight, awesome motor.

Wayne Comfort egging me on and letting me use his tower.
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The recovery used a featherweight Raven and Tracker on an SLA printed "Av-Tree" using Siraya-tech Blu "tough" resin. It fits great in the Kevlar nosecone, but not this one, so I had to augment the O-ring with some electrical tape to increase the diameter a bit. The final version will have no tape and have better organized wiring.
IMG-4366.jpg


I also used the new Tinder Rocketry Mako cable cutter. They are suuuuuper cool. I was an early adopter of cable cutters and am still a cable cutter apologist. Some things that always made me nervous about any other cable cutter was the power, the size of the zip-tie and the E-match shorting out on the body or getting crushed when you closed it. The Makos solve all these problems. The way the E-match fits into the cap is genius. They're also exhaustless, quiet and easy to clean. Cable cutter evolved!

https://www.tinderrocketry.com/the-mako-cutter

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It was a great flight. Love Loki motors, badass as always. 19,900', M1.46. Landed 1.5 miles away and walked (what we couldn't drive) right up to it with the Featherweight Tracker.


Happy landing, rode off into the sunset...
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The end.
 
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watheyak

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Hello from Teterboro, NJ.

Normally I take an airline flight to wherever the plane I'm to fly happens to be. This week I got to skip all that and picked up my plane locally. So I decided to bring this project with me to work and work on it in my hotel room in my downtime. One perk of my job is that I'm not subject to the TSA 3.5oz liquids rule, but I'm not sure if they had intended a quart of Cotronics be part of the exemption. I may ship the project home at the end of my work week. It's probably be ok, but the less explaining to TSA agents, the better.

Long story short, I started some finish sanding and adding the rest of the fillets. There'll be a few more layers to the fillets that are shown here, and much sculpting.

IMG-4448.jpg
 

FALCON9151U

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So forgive me for being a noob , but that 3D printed nose cone tip that you will be torture testing, will you heat it in a controlled temp environment and test it all the way to failure?
 

watheyak

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So forgive me for being a noob , but that 3D printed nose cone tip that you will be torture testing, will you heat it in a controlled temp environment and test it all the way to failure?
I think lots more research and testing is needed before I move forward with the 3D printed tip. It shows promise, for sure. Resin technology, especially in the engineering resins is moving pretty quick. Exciting...

So this tip will be boring old aluminum.
 

watheyak

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Lots of boring fillet sanding going on with this project lately. I figured I'd spare you guys the pics of all the dust.

Little by little I've made in insert for the nosecone that will will hold the recovery laundry and double as the coupler. I extended the tube that makes up this insert all the way to where it matches the inner diameter of the nosecone. In a previous version the cable cutter had hung up on the lip created by the coupler up inside the nosecone, preventing the parachute bundle from deploying. This ensures a smooth pathway for the parachute and cable cutter bundle to deploy.

It wasn't until I made this screenshot that I realized that the LoRa antenna from the Featherweight Tracker extends down into this tube slightly. I may have to shorten it. Attentions paid to attenuation and so forth...

Extended Sleeve.png

In the meantime, here's some shots of the build. I essentially made a tube with the correct ID for the female end of the coupler, added some thickness and split-resistance to it with some unidirectional CF, trimmed it all up a bit and then made a fixture to make sure that it all gets glued together straight. All Cotronics 4461. The whole nosecone will be post-cured as one item when complete.

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I forgot to get pics of wrapping the uni. Here's a representative after-the-fact photo-
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in the pic below, from the top down-
Nosecone
Sleeve/female coupler
Male coupler
Loki extended forward closure
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The pics that follow are after subsequent levels of insertion. Like Russian nesting dolls. Or something. The all thread with the ferrule is just there to assure the sleeve insert gets glued into the nosecone straight, and therefore ensures that the nosecone goes on the rocket straight. Once everything is glued together, the scientifically calibrated super-alignment device (all-thread and ferrule thingy) will be removed.
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Straight! Hopefully.
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More later. Back to sanding.
 

watheyak

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After staring at it for an eternity trying to figure out how not to get glue in all the places I didn't want it, I finally got the insert glued into the nose. The Scotch tape keeps it from dripping down inside the coupler, and there's a generous amount of Frekote mold release on the inner coupler and the aluminum collar at the bottom. The tape will be cut out while the epoxy is still leathery and the all thread alignment jig will come out with the Loki closure and be removed.

IMG-4582.jpg


Buttered with a mixture of Cotronics 4461, cotton flox and milled fiberglass. The inside of the nosecone was similarly buttered. (If you lean towards the frugal, cotton flox is really just belly button lint. Start your collection now.)

IMG-4585.jpg


Hopefully it all comes apart and I didn't just create a desk sculpture. Fingers crossed.

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AeroAggie

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Looks great! I hope those slide together with a very satisfying *snick*
 

watheyak

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The fincan is essentially done. Filleted, sanded and polished. The fillets look a little sloppier than they actually are. I'm pretty happy with how smooth and uniform they turned out despite their appearance. The whole thing was polished using a Dremel Versa and 3M Finesse It II. There may be more polishing to come, depending on time.

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IMG-4611.jpg
 

watheyak

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The nosecone is pretty much complete as well. In a previous post I showed how the coupler insert at the base was aligned and glued in. In this next step, the tip as potted in using Cotronics 4461. Much care was taken to get the tip perfectly centered on the longitudinal axis of the rocket. I think I got it, but I'm still kinda nervous about this detail.

Also as stated previously, I used an aluminum tip from a Curtis nosecone. It's threaded at the base and I tried to use that threading and various washers and adapters to attach the tip, but in the end I just wasn't happy with it or confident in it's fit. I ended up potting it in using the Cotronics 4461.

Also potted in was the 8-32 titanium all-thread for the av-bay attachment. There was a thread here a while back about all-thread vs. antennas. They're like a glue thread, lot's of passionate opinions, scattered nuggets of actual fact. In this thread it mentioned that perhaps titanium all-thread would attenuate the signall less than a more ferrous metal. Who knows? Sounds dubious and well reasoned all at the same time, right? The rocket launched is post #66 used boring old stainless steel, and the tracker worked just fine. But I am a sucker, and titanium sounds neat. So titanium it is...

All the all-threads. Very boring picture. Guess which is the Ti-
IMG-4598.jpg


I used a cardboard tube to pour the epoxy into the tip while keeping the rest of the nosecone interior clean. The Cotronics has been banished from the house by my wife.
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The final product, all polished up. No paint, just high-temp epoxy, some composites and aluminum. Oh! and titanium. It's currently getting baked at 250° for four hours to post cure the 4461.
IMG-4621.jpg
 
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watheyak

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The stars are aligning...

I'm getting home from my work week quite a bit earlier than normal, which might make this possible.... As long as I can hustle and get the electronics swapped onto the new version of my sled, plus a bunch of loose ends, I should be in pretty good shape to launch this at the TRAPHX monthly launch this weekend.

Also needing final assembly is an Attebery Performance Engineering launch tower, like the one here-
The club is the proud owner of one thanks to generous donations from some club members. Luckily I'll have some help putting it together.

Pretty excited, pretty nervous!

I'll post pics of the final assembly, and of course pics of the launch regardless of the results.
 

Wayco

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I've been monitoring winds aloft this week, pretty consistent out of the West, 55 mph at 18k, 69 mph at 24k today. Sharon and I will be out for Saturday, hoping to witness this flight and burn a big M sparky.
I will bring out that extra Loki motor if you are still interested....
 
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