Building my SpaceX BFR

 I've always admired the retro look of the SpaceX rockets but didn't want to pay $150 for the ready-to-fly SpaceX Falcon 9 model from Estes.  When browsing Thingiverse I came across a flying version of the Starship Super-Heavy by jsheedy, previously known as the SpaceX "BFR" (let's go with "Big Flying Rocket").   The author provided files to 3D print the "BFR" nose cone, transition and fins designed to take my favorite 2.6" diameter body tube (BT-80).  I used some modifications made by jgutz20 on Thingiverse, allowing just the Starship to be a rocket by itself without needing a booster stage.  

Starship BT-80 Full by jgutz20 on Thingiverse, not mine!

I printed jgutz20's nose cone, which includes modifications attach a parachute and shock cord and 3D printed launch lugs, along with other parts from jsheedy (below), then built an OpenRocket simulation file based on their weights and fin shape to ensure its stability and predict how high it will fly.

BFR nose on printer (with 3D "tree" supports)

Doing a test fit of the BFR nose on a BT-80 body tube

3D printing the BFR base (showing the infill)

BFR base almost done printing

Printing the fins (showing infill)

Finished 3D printed parts ready to assemble

Using OpenRocket, I built a simulation of the rocket, including decals to match the SpaceX Starship appearance.  Here's simulation of the rocket in flight:

Based upon the finished weight of all the parts, it's projected to fly 640 feet on an F15-4 (380 feet on an E16-4).

I'll definitely have to use the JLCR and my new GPS tracker when I launch this!

I still need to cut the upper (BFR) body tube and glue those together along with the engine mount, attach Kevlar and a shock cord, then paint the BFR top half with silver, some cabin windows and the black slits shown in jgutz20's close-up above, along with the black heat shield on the back half of the BFR.  Luckily, I have a 3D printed BT-80 tube cutting guide (based on these files) available to help prepare the different tube lengths for this rocket.  I'll probably try printing a SpaceX decal to give the booster some color to make it easier to find if it gets separated.

I'll see how this flies as a single engine rocket as shown above.  Depending on the flight profile, I might try rebuilding it with the BFR as a second stage, using the modifications shown by jgutz20, if I can figure out how to ignite the second stage.  One possibility would be to extend the engine mount to the base of the BFR in hopes of passing sparks to ignite the second stage (probably a D12-3 or similar), though it would probably necessitate me learning how to do electronic ignition of the upper stage.  Stay tuned...

Feb. 26th Update:

It's a sunny day in Chicago (68 F!) so I decided to go ahead and paint my BFR.  I'd glued things together with super glue yesterday, including adding 4.5 oz of lead fishing sinkers in the tip of the nose cone then pouring epoxy around it to hold it in place because OpenRocket predicted I need that for stability.

Assembling the SBR booster using super glue

Looking down inside nose cone at lead weights covered with epoxy

After painting the booster with primer, sanding, then painting with Rustoleum white enamel and letting it dry I attached the SpaceX decal I printed as described in an earlier attempt.  This time, I trimmed very close to the decal, soaked it for just 30 seconds in warm water then slid it quickly into place and it turned out great:

Painted BFR booster with SpaceX decal I printed and applied

I also primed, sanded, filled some gaps with DAP, sanded then painted the BFR nose with Rust-Oleum Metallic silver spray paint on the top.  I let that dry a couple of hours, taped the edges with green Frog tape then painted the BFR bottom half with Rust-Oleum Metallic black spray paint.

Painting the bottom black (silver surface taped off with Frog tape)

BFR after removing the Frog tape

I'll need to paint the "windows" on the silver side of the capsule and paint the notches behind the windows black, then cover with a coating of clear vinyl,  but think this is ready to be launched on an F15-4!

OpenRocket prediction of SpaceX BFR Starship on an F15-4 engine

Feb 28 Update:

The BFR is complete and ready to fly: