QUAKE (QU8K) 50% 3D Print Build

[DRAGON64]

I recently acquired a 3D printer, specifically to use for my hobby interests. One of those interests is scratch building rockets. This is my first (flyable) rocket off of the printer, a downscale version of Derrick Deville's QU8K rocket. The QU8K is 8" in dia. and flew on a "Q" motor to 121,000ft agl in serach of the Carmack Prize. My downscale is based on the nominal BT-60 airframe, and utilizes a 24mm motor mount to fly on "The Mighty D" as well as the Aerotech RMS 24/40 and 24/60 motors.

This rocket was initially designed in SoldWorks 2018, and sliced in Cura 3.6.0. The printer is a Creality CR-10S. The printed parts are printed with a PETG Filament, as PETG has excellent strength and heat properties (won't melt as easy as PLA filament). The body and motor tubes came in a Flis Kits Builder Extravaganza kit.

The Components:


Hints:

For best results, the fin can was printed with supports, as a number of prints had issues with sagging material at the trailing edge of the fins. The fin can is mostly wall construction, except for the integral launch lug. This print was sliced with 50% infil using "Lines" as the patern.


The nosecone is also mostly a wall construction, and many of the thicker parts like the base, and the last 3" of the nose are sliced with a 50% infill using the same Lines pattern.



The coupler, baffle and upper rail lug are printed with 100% infill, as they serve as recovery attachment points, where I want as much strength as PETG filament has to offer.


Should you wish to build your own QU8K model, all of the files can be found at Thingiverse using this link:

https://www.thingiverse.com/thing:3388752

 

[DRAGON64]

I have created a basic RockSim (v9) for the QUAKE. There is no recovery hardware for the file, as the end user would want to add there own components. What is contained are just the tubes and printed parts. The coupler, nosecone and baffle have bulkheads added to them in the RockSim file to simulate a completed components, as they are actually printed as one part each (does that make sense?).



If you have not done so, you will need to edited the Material data base to add PETG to use this file. That is to say if you plan to print, and not carve the parts from Balsa...

Here is a generic material spec shown added to the material data base in RockSim. Make to sure to check the appropriate boxes where you would wish to use PETG in your build:



RockSim (v9) file attached.

 

[DRAGON64]

Fin Can build: The build starts with the booster using the fin can with one centering ring and the 10.25" long 24mm motor tube.



One end of the motor tube is glued flush in place at the end of the fin can with JB Weld. The centering ring is slipped over the 24mm motor tube and slid in place at the top of the fin can, there is no gluing uet for the centering ring. A scrap piece of BT-60 was slid over the centering ring and down onto the fin can. This was kept in place until the JB Weld set up (over night).





After a full cure of the JB Weld, the crap piece of BT-60 tube was removed, and the centering ring was glued in place on top of the fin can with Testors model cement.



The last centering ring is glued in place flush with the top end of the motor tube using 5-minute epoxy. The left over epoxy was smeared around the inside of the motor tube to keep the tube end from burning through pre-maturely... No sense wasting it.



Next up is baffle and coupler assembly.

 

[DRAGON64]

Baffle & Coupler Assembly: The parts I used for this build are; the baffle, coupler, (2) small eyelets, (1) 5.875" payload tube, a short piece of 1/8" dia. Kevlar, and misc heat shrink.

Each eyelet is screwed into the baffel and coupler fully, then removed. Thin CA is applied to each hole, and the eyelets are screwed back in place fully.


One end of the kevlar is slipped through the eyelet in the baffle and a simple knot is applied. Then a short piece of heat shrink is slid in place acpturing the loose end inside.



Using thin CA I soaked the knot, as well as the inside of the heat shrink. Then the heat was applied to the heat shrink until it was fully shrunk. The assembly was hung up until cured.


I kind of wing it from here, but I am planning on inserting the baffle 7" deep into the booaster tube once assembled, and that helped to determine the over-all length of the finished kevlar shockcord mount (including knot). Like the process; heat shrink was installed; loop and knot made; everything was soaked with CA, and the heat shink was shrunk in place. Now we have a completed hard point for shock cord mounting.


The coupler was much simpler; a mark was made at the halfway point...


And the coulpler was glued in place inside of the payload tube using 5-minute epoxy... and set aside to dry.



Next up is the booster assembly build.

 

[DRAGON64]

I ordered an 18" X-form chute for this rocket. I also have some paracord in orange for the shock cord. I am re-thinking the paracord, as it may drive the weight of the rocket up, as well as consume the limited chute compartment. We'll see once I have everything assembled for flight.



Quite the quality chute, I may need to stock up if I continue to build these low power rockets from 3D print.

 

[DRAGON64]

The booster was glued to the fin can with a generous amount of 5-minute epoxy. Prior to installing the booster tube to the fincan, be sure to draw a line the length of the tube. This line will be used to line up with a mark you make on the fin can indicating the center line of the rail lug on the fin can. I gave the fin can a few twists to make sure there was ample glue coverage before finally lining up the line and center mark. While was drying, I sanded off a place on the booster tube, roughly about the location of the upper centering, and this is where I glued the final rail lug in place. Medium CA was used here.



The lug was pressed well into place... this is why you want the lug placed close the location of the centering ring... keeps the tube from caving in when you press the lug in place. Tape was placed over the lug to ensure it did not pop off before the CA had cured.



The assembled rocket is now ready for priming and paint (weather permitting). The nose cone will either be glued in place, or will be friction fit with take, I am not sure which way I will go yet.



Note here in this image, I have used masking tape to tape off the lugs. This is to keep from there being too much primer and paint an the lugs, so as to cause too much friction on the launch rail.

 

[DRAGON64]

As it turned out, this past wekend the weather was perfect for some priming, so the Quake rocket got a single coat of KILZ before the can ran out.



Not pictured here with my 8MP camera, are the lines left behind from the printing process... or at least my printing process. But with a coat of primer, the lines really become visible, and that tells me I have my work cut out for getting the finish to smooth out... I'll do what I can. All rockets look pretty good from 3' away!

Will post a paint image of two once the weather lets me... However! I may get to fly the Quake rocket at a local launch this weekend...

 

[BABAR]

I ordered an 18" X-form chute for this rocket. I also have some paracord in orange for the shock cord. I am re-thinking the paracord, as it may drive the weight of the rocket up, as well as consume the limited chute compartment. We'll see once I have everything assembled for flight.

View attachment 373862

Quite the quality chute, I may need to stock up if I continue to build these low power rockets from 3D print.

View attachment 373863

Cool build.

Not too familiar with the X-chute, but I thought I saw someone fly one about 5 years back without a swivel. The chute spun and twisted shroud lines on descent without the swivel and basically streamered in. It wasn’t pretty.

 

[Leo]

Looking good.....

 

[DRAGON64]

I agree, I believe the chute can benefit from a swivel. Without motor or recovery, the build is running around 7oz. The 18" chute should work well for weight, and the x-form should keep drift to a minimum... other wise I will see how best to employ some sort dual deploy.

 

[Bruiser]

Nice looking rocket. I really admire you guys who are working with the printing. The parts you are producing are great!

-Bob

 

[DRAGON64]

Thank you Bob! The design process is as much fun as the printing process. It is amazing to me now that we can print our imaginations... And that which we cannot buy.

 

[Nytrunner]

Nice! Have you been hanging around Turbulent_Sphere and his print shenanigans at work again?

 

[DRAGON64]

Guilty...

 

[DRAGON64]

With the booster and payload in transparency, you can see general location of the 3D printed parts. The longer 24mm motor tube acts as a small "stuffer" tube to take up some of the ejection volume.

 

[Nytrunner]

Guilty...

Hah! Did y'all go launch his 3D spool last weekend?

 

[DRAGON64]

I saw the spool, and heard there may have been a launch, but cannot confirm if that was it. My office mate said he saw a video of the launch at a meeting, but gave no details, as he not a model rocketeer.

 

[Rockyt]

Something like this may help with the 'fingerprinting' of 3D parts.

https://www.amazon.com/dp/B00PFXK4JY/?tag=skimlinks_replacement-20

 

[OhioFlyer]

Just finished up printing all the parts for my build. One thing is noted is that the motor retainer doesn't lock in and feels a bit loose. Is that by design? I don't have an aerotech case to test it with (printed both retainers which fit the same) so I can't check if they lock down against the case closure.

 

[Pepe Le Pew]

 

[OhioFlyer]

Not sure what that's implying but I'm just trying to understand if it's intentional or a print issue on my end. The parts fit well together and are otherwise dimensionally correct from what I can tell (based on a quick check with a bt60 tube I have). I'm printing in PETG+ for what it's worth.

 

[Pepe Le Pew]

I am getting my popcorn and watching this thread with great interest! Great job Thanks for sharing!!!

 

[OhioFlyer]

I am getting my popcorn and watching this thread with great interest! Great job Thanks for sharing!!!

Gotcha, sorry about jumping on ya in my confusion.

It's a nice design, I've got it all printed out and will likely build it at our club build night this week. Should be able to grab an AT SU motor 24/40 case to test fit.

 

[Pepe Le Pew]

Awesome, I can wait to see a launch, I bet it will be a speck! Great job. I never thought of using testors model cement for the PLA I am using. I will also try it on the PETG filament. Thanks for all the ideas!

 

[Karl]

Got to fly mine yesterday. Arrow straight on a D12, thanks for the STL's.

 

[Hobie1dog]

 

[OhioFlyer]

Also had a great flight with mine. Flew it on an F44. Flew nice and straight. Landed in a tree but a club member managed to get it down for me.

 

[maddmaxx11]

Anyone have problems with the CG being to far back with a D or larger motor?

 

[maddmaxx11]

I finally flew my Quake with an Aerotech D15. The CG was 1.3 caliber’s with that motor. The rocket flew as strait as an arrow to about 600 feet with a good recovery. If you fly on an E or F motor you will need weight in the nose or make the rocket longer.

 

[maddmaxx11]

Also had a great flight with mine. Flew it on an F44. Flew nice and straight. Landed in a tree but a club member managed to get it down for me.

Did you add any nose weight for the F44 or was it ok without?