Falcon Heavy Build

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hermanjc

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Starting a new Falcon Heavy build. Scaled to BT-55 body tubes. Body Tubes and Motor Mounts are from Estes, with the some parts from a Designer Special Kit, although I did make the 2 engine hooks from windshield wiper blades (I had already used up the ones in the kit). Plan to fabricate my own booster release mechanism similar to the one sold by Apogee with their booster pod kits. Center core has a motor mount for a 24mm motor, boosters have motor mounts for 18mm. From end to end it should stand right about 24 inches. I am going to sand down balsa blocks for the booster nose cones, and I found that an old cardboard tube from some kraft paper was a perfect fit for BT-55 couples/nose cone bases. I am debating having a friend 3d print the Nose/Fairing for the center core so that it opens on release, or just making a balsa block plus body tube/transition nose cone from scratch. Unless I can find a bunch of mini nose cones (old pen caps maybe?) I will likely have a friend 3d print that for the motor end as well. He is certainly planning to print me some grid fins and landing legs. I will have him include slots/tabs on the landing fins for attaching clear polycarbonate fins for stability. More to come...

Motor Mounts, Prepped Booster Balsa Nose Cone blocks
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Booster Release Mechanism Balsa Spacers, sanded to match BT-55 contour. Gap is 5.5mm between body tubes for scale.
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Boosters held to center core with rubber bands for visualization.
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Continued with fabrication of the booster attachment/release mechanism. Used a scroll saw to cut out the support and alignment bars that will be mounted on each booster as well as the nose cone hook and base pivot that will go in the center core blocks. Both are made from polycarbonate sheeting.
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The nose cone hooks and pivots were epoxied into slots cut into the center core blocks. First I drilled small holes through the polycarbonate to ensure the epoxy had a good hold.
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After laying everything together I am going to need to adjust the length of the booster alignment bars a little shorter. Next up cutting the slots in the boosters and getting these parts bonded to the body tubes.
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Tonight's progress included glueing the booster attachments to the center core, bonding the alignment bars on the boosters, shaping the booster nose cones, installing rail buttons and the motor mounts. Everything is fitting well together and the boosters are secure with the nose cones on and relatively easily fall away with them off. Next up... The payload fairing and second stage.

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Fun following along! Great project. How did you make the nose cones?

Thank you. The booster nose cones were made from balsa blocks (3 glued pieces of 0.5" thick sheet) and whittled/sanded to shape. The same went with the center core fairing top, the middle was a paper tube I had held onto that was pretty much perfect for scale. The bottom was more 0.5" balsa shaped and glued to a coupler to slip in the top of the center core.

Tonight I hand cut and contour sanded the 12 landing legs. Glued up the first set, and will check the fit with the center core tomorrow before doing the rest.
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Landing legs are on and looking good. I am glad I decided to hand make these out of balsa instead of 3D print as it will help keep the CG forward. Next I'll make some grid fins in a similar fashion and cut out polycarbonate fins.
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Added on grid fins and conduits. All cut out of balsa. I intentionally have the grid fins and conduits "lower" down the bodies than scale because I did not want to attach them to the booster nose cones and deal with them breaking off on ejection/landing. Next I need to add the nozzles around each base (sourced from Dollar Tree pen caps) and then cut clear polycarbonate fins and fin slots.
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Are you adding a third rail button at the bottom, or flying with just the two higher rail buttons?
-Bob
Just the two buttons you see. They are more central than they appear in that picture with the second stage and fairing now attached. The CG will likely end up right at about the lower button (if my rocksim model is accurate).
 
While the boosters and center core are getting paint, I decided to split the nose in two so the fairings will separate on ejection. Perhaps a scale Roadster with a small chute/streamer will emerge? I'm adding a small plastic "hook" towards the nose to keep the halves tight on accent, and will likely add opposing magnets by the base to encourage the separation.
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Paint is done. Decals are on. Now I just need to make a final decision on fin size (might try a couple different options and swing test before bonding). Added a "custom" logo to the fairing: HASX = Hermann Air and Space Exploration :)
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Some up close shots of how the booster mounts work.
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And the fairing halves. Small hook at the top to keep it together while base is in the center core tube. Need to wait for magnets to arrive to bond in bottom to push the halves apart on ejection.
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I might end this scratch build thread here and post final results and flights in the Scale forum from this point forward.
 
Small update. Added opposing magnets to the fairing halves. Now when the nose is ejected the fairings instantly separate. Last things I need to do are add fins and parachutes/streamers.

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