3D printing a Star Wars X-Wing!

I've had some printer problems in the past month where the print head kept moving but nothing was coming out.  After a lot of Googling and anguish I figured out I needed to replace the nozzle on the print head and how to do it when the filament was stuck and wouldn't retract.  Anyway, I'm back in business now.

NCR X-Wing Fighter from 1996 Estes Catalog

I came across a cool looking build thread on The Rocketry Forum entitled X-Wing Fighter Builds. The author, The Red Darren, was going through several different iterations of 3D printing and building a Star Wars X-Wing using balsa for the fins.  He's still perfecting his project, but shared a couple of STL files which got me interested.  I printed the parts, which are meant to be assembled like shown here:

I quickly recognized the solid parts would be hard to turn into a rocket.  I'd made a couple of attempts at using my printer's ability to print in "vase mode", where one thin continuous layer is printed on a single object.  I used it to make some watering pitchers for my wife's garden, and was able to print a V2-like rocket entirely in vase mode (using clear PLA, below):

However, this approach was unable to handle external surfaces, such as when I tried to print an X-1 model in vase mode (note the strings of PLA hanging off the back of the wings):

I had done some research for ways to merge objects in Tinkercad when trying to recreate the Silver Comet nose cone.  As part of that I played around with hollowing out individual parts using Tinkercad by duplicating an object, separating the duplicate and shrinking it so it was ~0.1 or 0.2 inches smaller in all dimensions than the original object, converting it to a hollow object then merging it back into the center of the original object and fusing them.  This worked, at least in my partial test bring of one object, though it was difficult to position the inner hollow object without breaking the surface:

I decided to abandon the original Rocketry Forum individual part approach for now since I couldn't quite see how to put these parts together like a normal rocket, and I couldn't see how his four engine mounts, designed to hold B or C engines, would eject a parachute for recovery.  Instead, I decided instead to try my duplicate, shrink & merge approach on complete X-Wing models from Thingiverse.  Basically, Kens3DPrintShop took a full X-Wing object, cut it in half through the wings and pulled out the laser canons to print separately.  I was able to open the two halves of the X-Wing in Tinkercad, do my copy and delete approach, then slice and 3D print each half.  The front half of the wings with the full nose section and cockpit after slicing in Cura 5.8.0, was predicted to take 1 day, 18 hours and four minutes (it actually took 44 hours on my printer).  The bottom half, hollowed out and with a round hole for a body tube to extend out the back, was predicted to take 1 day, 1 hour and 5 minutes (it took closer to 27 hours).  The two pieces, after trimming off the brims around the flat surfaces, fit together beautifully, stand 15 1/2 inches tall and weigh 16 ounces together (I printed using PLA at 0.2 mm using 30% infill).  This large of an object requires a large print surface like my Anycubic Kobra Max (its print area is 15.7" wide x 15.7" deep x 17.7" high).

Estes sold many different versions of the X-Wing, and I found old plans for the Estes #1298 X-Wing Fighter (1978), the Estes #1302 Maxi-Brute X-Wing Fighter (1978), the Estes #2103 X-Wing Fighter (1997) and the NCR Estes #3540 (1997) Star Wars X-wing Fighter (the catalog said the NCR version is “Huge. Actual size of the movie special effects model.”).  The NCR version was 20 inches tall with a wingspan of 18” and weighed 30 oz without the motor.  Mine is 15.5 inches tall, with a wingspan of about 14" and weighs 16 oz without the motor.  The NCR version used rear-engine ejection (like my Pringles MKII Bomb rocket); the others were front ejection which would require me cutting the nose cone to eject the parachute out the front.  The NCR and Estes Maxi-Brrute (21 5/8” tall and weighed 11 oz) are currently listed on EBay for $750 or more!  I'd rather figure out how to print my own and see if it flies!

On test fitting, I noticed there were slight gaps behind the R2D2 on top and near the tip of the nose cone on the bottom.  I'll try filling these with epoxy putty.  I'm not planning on painting this version, but did print some decals (resized from the NCR version) to dress it up a bit and make it easier to spot during flight.  I may use a paint brush to paint R2D2 because the X-Wing would look naked without him!

Speaking of flight, I made a crude OpenRocket simulation, incorporating the four wings, the shapes of the over wing engine exhausts, and the finished printed weights.  Based upon that simulation, I will need an E16-4 or an F15-4 for flight.  If I put 3 ounces of epoxy + lead ballast in the nose to achieve ~1.0 cal stability, the simulation predicts 266 feet on an E16-4 and 408 feet on an F15-4.  Separately, I had checked the Estes catalog for the Engine Time/Thrust Curves Chart and found only an E or F engine was capable of lifting the 16 ounce rocket. 

ToDo:  I'm going to try to build the rear-ejection part using the NCR plans as a guide.  I'll either use a streamer for the engine tube or recover it along with the rocket by connecting both to some Kevlar connected to an PETG-printed engine block at the front of the main body tube.

An illustration of rear ejection my copy of Tim Van Milligan's book, "Model Rocket Design and Construction"

I need to use some epoxy putty to patch a couple of holes in the nose of my X-Wing, add ballast to the nose with epoxy, then glue the two halves together (with epoxy) and then find a way to anchor a BT-60 body tube inside the hollowed out rocket (after glueing the ballast in the nose), and build a 29 mm engine mount to slide out of the BT-60 upon ejection and pull out the parachute for recovery; I may use a streamer on the engine tube (as above) or join it to the main recovery using Kevlar.  I'll probably wrap the parachute with a flame retardant parachute protector because of the tight space.  Unfortunately, I need to order some new BT-60 body tubes because all I have is short scrap tubing.  I may try anchoring the BT-60 using spray foam insulation or build some centering rings adapted to fit inside the hollowed out model, then use some BT-60 centering rings to support the 29 mm engine mount.  This rocket won't be able to use the JLCR for chute release or the GPS tracker due to the configuration.  I'll post updates when finished and ready to launch.