• Epoxy reinforcement

    lion mclionhead • 2 days ago • 0 comments

    Made a new ship with thicker walls.  Epoxied the trouble spots.

    It seemed to shrink less.  Then the nose started sagging along the Z seam, where it under extruded.

    So that was a 3rd trouble spot, but it's never going to be completely bulletproof as long as it's made of PETG.

    Made the final movie about it.  Some window sections always shrink, but it's less garish.

    The windows actually diffuse the upward smoke, emphasizing the backflow smoke in ways other incense burners don't.  All the other incense burners have the upward smoke fully exposed.

  • Tower foundation

    lion mclionhead • 3 days ago • 0 comments

    Plain old bolts in MDF won the foundation battle.

    The shrinking bit of fuselage might benefit from an epoxy layer. Epoxy might also bond PETG welds.

    With the tower anchored, it was easiest to tip over the entire diorama to dump the ashes.  The rocket doesn't have to unhook from the chopsticks at all, except for playing with it.  A more assertive catching pin was back on the table.

    When this project began in Jan 2023, no-one knew what a landed starship would look like after being caught by the launch tower.  The original idea was just a smoke plume from powered flight.  Then it became a pool of smoke from venting before flight.  The sight of the actual landed booster hanging from the chopsticks, smoking on the bottom was a perfect match for an incense burner. To fully appreciate it though, you have to watch it burning.

  • 1st landing

    lion mclionhead • 5 days ago • 0 comments

    A few printouts made it clear that spring loaded chopsticks would be more ideal than hooking catch points.  It's just really fiddly to get the catch points to engage & disengage without making a mess of the ashes.

    It wouldn't be possible to completely open spring loaded chopsticks though.  It wouldn't be as visually appealing with big old springs on each side.

    Accepting the problems for now, the 1st burn looked really like it just landed in real life, with the engines smoking & the whole rocket hanging from the chopsticks. 

    Ash removal was a complete mess, as expected.  More tweeking of the catching  points got it at least possible to empty the ashes with a lot of care.

    Didn't take long to notice the ship sitting lower after every landing burn.  The walls were melting.

    CA glue can buy it time, but CA doesn't stick to PETG permanently.  Thicker walls & more layers for it to pack down would be the next step.  Definitely not getting narrower than 50mm.

  • Chopstick model

    lion mclionhead • 05/07/2025 at 06:44 • 0 comments

    The guy who designed the chopsticks is made of different stuff than lions.  It was pretty hard to come up with this crude model.  The amount of time they had to design the real thing, between the announcement in Dec 30, 2020 

    & the foundation in Feb 2021 was incredibly short.  

    These kinds of structures begin with a rough idea & are massaged over time.  The launch tower might have been manely left over from the original 2016 design, which was always going to stack it.  

    Technically, the tower had 4 years while the arms modified for catching were revealed in July 2021 so the incremental  change had 7 months.

    As slow as lions are in comparison to leet ME's, the memory is still fresh of when a model like this would have taken many weeks of carving & gluing wood pieces without ever achieving the fidelity it has.

    A machine that only deposits filament required some compromises from  welded steel tubes.  It was decided to have the chopsticks hook on the rocket instead of being spring loaded.  A friction enhancing O ring should keep them from flopping around.  They're still using a more assertive tab than the real catching pins.

    Ideas of fully motorizing the thing continued to be dashed  by the lack of space, the time required for an automated system to reposition the rocket, the extra jig required to stage it off the chopsticks.  The ground jig would still be loaded manually.

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    Cura couldn't slice the multiple overlapping rods in the chopstick model.  It needed a remesh modifier in blender.  .2mm voxels might be optimum.

    It doesn't open as wide as the real thing.

    With everything mocked up without catching pins, noted it would make an entertaining, expensive pendulum clock.  The tower segments below the claw have to be glued to keep it from bending, but also have to allow the claw to slide on.  The top section doesn't have to be glued on, but ideally the claw could slide on from both ends.  

    The foundation was a trouble spot.  It should be glued on but has to be wider than the tower.  It could be bolted on the rear by melting a hole.  Only the rear column needs to be held down.  Post tensioning wire would require an ugly top piece.  The tower can be stuck to a sheet of tin with a magnet.

  • 50x170mm ship

    lion mclionhead • 05/06/2025 at 18:35 • 0 comments

    Created the PETG version.

    The most miserable part of assembly is creating the heat break.

    It might be possible to use a big old blob of caulking as an insulator directly on PETG.  There might be other materials, but they cost money.

    This kind of welding system has a bead on 2 axes, which makes it surprisingly rigid, but it's damn hard to align without a jig.  The welding panel also engages the clamshell.

    The catching system may not attach to the chopsticks, after it's heated & deformed. 

    By using smaller holes & covering more area on both sides, lions believe the ventilation system looks less like windows & more like a ventilation system.  It was decided that holes on both sides should create a film cooling effect.  It's going to  lose the effect of a smoking heat shield, but no-one really knows if both sides won't smoke in reality.

    This one looked especially good.  There was a moment of pride in it before the melt test.  Would increase the wall thickness to 1.5mm or add vertical stringers between the holes.  Thicker walls would reduce the airflow.

    The holes seemed to diffuse the rising smoke more & cause the backflow to be emphasized.  The engine section raised on the test stand has been a lot more visually appealing than the engine section flat on the table. 

    It once again softened & warped.  Vertical stringers should reduce this, but hanging it from the chopsticks should be a game changer.  The loads won't go through the deformed section.  Kind of disappointing that 50mm isn't making any obvious difference. 

  • 50mm ship test

    lion mclionhead • 05/05/2025 at 07:09 • 0 comments

    18g of PLA later, had a 1st attempt at something that could hang from chopsticks.

    This one had caulking to bond the heat break to the PLA.  44mm seemed to be less than ideal.  A thermometer showed it hitting 70C on the bottom.  The rocket looks proportional enough to go at least 10mm shorter, but the mane limitation on the rocket height is the heat break height.  Mounting the heat break lower requires splitting the rear fins.

    The clamshell mechanism wasn't very satisfying.  Tried coming up with a window arrangement which would make it smoke from the heat shield side, as if it just landed & was still smoking.  2 big holes are where the chopsticks are supposed to clamp on.  The landing pins are  decorative.

     Helas, it just looked like the windows were on the wrong side.  At least it looked like convincing landing smoke from the front.  A better idea might be a larger number of smaller windows, so they don't look like windows.  The last resort is to completely open the heat shield side.  The open heat shield honestly didn't look any worse than the window shaped holes.

    50mm PLA still melted, so it's going back to PETG for at least the area above the gas seal.  The perforated side fared better than the solid side.

    The engine section stayed cold.  Surprising PETG held up at only 40mm. 

  • Chopstick concepts

    lion mclionhead • 04/29/2025 at 18:52 • 0 comments

    An automated system which pools smoke above the cone, then pulses a fan to inject fresh air & force the smoke out the bottom is about as equally appealing as the proven design of a gas seal separating the updraft from the backflow.  The rising & falling smoke from the gas seal really looks like a ship that just re-entered, with its heat shield & engines smoking.  The mane advantage with forced air is it can be a fully enclosed ship.  The mane disadvantage is the smoke is always going to be less prominent than passive airflow.

    The real ship now has vents in the engine section to vent all the pesky leaks & fires.  Something like that could be a substitute for the big old incense holes.  A larger section above the cone could be perforated.  It might cool down more without looking terrible.  PETG might not have enough layer adhesion to make perforations.

    In order for the clamshell chopsticks to work the gas seal is going to join to the chopsticks with a metal V hangar.  The metal V opens & closes, raising the gas seal when it's open & lowering the gas seal when it's closed.  The next question is how to get the nose cone to close as tightly as possible. The nose cone needs to open sideways. The chopsticks really need a spring mechanism to press the sides together.

    The chopsticks need to close 1st against 1 spring mechanism & then the gas seal needs to travel up against another spring mechanism.  The chopstick closing is relatively simple.  The gas seal raising would require a vertical degree of freedom for the V hangar.  Space limitations almost require using cables.

    Assortment of chopstick photos:

    The next question is how far out is the ship going to land? Based on the position of the pillows, it should land on the middle.  The pillows don't extend to the end.  Based on the position of the launch pad, it should land on the end.  The pillows could slide out for the landing.

    The 2 pistons have a serious mechanical disadvantage, but 2 pushrods in those positions could do the job.

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    A few thought experiments showed the chopsticks can't move.  The incense cone has to be stable & no mechanism would keep it stable if anything besides the nose cone moved.  The joint between a horizontally rotating chopstick & a vertically moving engine section would be a wobbly 2 axis.

    The engine section has to be hard mounted on stationary chopsticks.  The nose cone has to be manually removable.  The user has to light the incense in the narrow gap between the chopsticks.  Then there's the problem of cleaning the ashes.  The engine section has to be easily removed from the chopsticks.

    The simplest design is V shaped risers attaching the engine section to the chopsticks.  The nose cone would fit over the V shaped risers.  The trick is making the engine section not wobble when sliding the nose cone down between the chopsticks.  The chopsticks just have to clamp on before lighting, but lighting between V risers would require an expensive torch.  It almost has to be 50mm diameter.  A static diorama is definitely less inspiring than a fully articulated thing.  Most backflow incense is bare pawed for lighting & then placed in the diorama.  There could be a tool for placing it in the ship after lighting.

    Another idea is to continue the previous 2 part design without V risers.  Light the engine section on a bench, attach a nose cone which is permanently fixed to the chopsticks, then raise the chopsticks to the landing position.  An assertive nose cone attachment without disturbing the incense would be difficult & might require some kind of jig.  Maybe they could be a clamshell, fixed to the chopsticks, that the user closes around the engine section on...

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  • Forced air backflow

    lion mclionhead • 04/24/2025 at 05:05 • 0 comments

    Because the cones get so much hotter than the sticks, practical diameters would begin at 50mm with the incense platform reduced from a square to a circle to buy more spacing.  The  booster has always been 40mm.

    The shortest 50mm ship that looks bearable is a gigantic 200mm but still shorter than the 248mm booster.  The booster is actually taller than the tallest practical print in the Ender 3.  Beyond 220mm, it has to be in the center of the print bed for the direct extruder to access the filament.

    The ship needs to separate in the middle, revealing a gap equal to the ship's diameter.  A 50mm diameter can provide a 50mm opening for lighting the cone.

    The last design needed a gas seal to keep the updraft in the cylinder from quenching the backflow.  To keep the gas seal from melting, it needed a metal tower to space the cone.  It used clay to bond the tower to the PETG but it could have used any filler.  The clay left a mess after it dried.

    A clamshell would need the gas seal to stay on 1 side, which limits the amount of exposed hot section.  Instead of a clamshell, it could be a door attached to the  hot section on 1 side.  The gas seal could be a labyrinth.

    No matter what, the space above the cone has to be swiss cheese.  That was really ugly last time.  Even if there's just 1 big hole in the back, it shows through the windows & looks horrible.  Having any smoke coming out above looks horrible.

    The most promising idea is having forced air from above.  It could have a timer, since incense has a fixed burn time.  The cone is going to shed a lot of ashes into the down draft, but all the exhaust is going to be down the flamey end.  It would allow a narrower diameter to stay cooler.  Then there's the matter of how much the downdraft is going to dissipate the smoke.

     It would have to be like a jet engine.  Air comes in 1 end, gets compressed, then heated by the incense, then goes down the bottom.  Nothing can go below the incense because it drops oil.

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    A test with forced air showed it can force the smoke out the bottom but it's very faint.  The only way to see anything is to pulse the fan.  Let a pool of smoke come out the top briefly, then force it out the bottom.  There is a surge of smoke at the very end of the burn.  The size of the bottom opening affects the visibility, with a smaller opening emitting more visible smoke.  The top & bottom opening size affect the rate of airflow.  Below a certain number of bottom holes, the smoke backs out through the fan.  Above a certain number of bottom holes, the smoke is too diffused.

    The best plume came from having the opening right below the cone, before the gas had a chance to mix.  It's still invisible without special lighting.  It might work better with a glycol smoke generator. 

    The idea of making all the smoke go down looks busted.  The gas seal was the key innovation which allowed the smoke to backflow in a less than perfect environment.  The hanging system would have to hang the fully assembled backflowing section with its heat sinking tower between the chopsticks, then have the nose section come together on top, when the chopsticks closed.  The section above the gas seal doesn't have to be air tight.  Lions normally run it without the nose cone because it's a pain to assemble.

    Verified it does indeed back flow when it's elevated. 

  • Chopstick idea

    lion mclionhead • 01/04/2024 at 03:19 • 0 comments

    The fleet.

    Helas, the backflow nose cone never got used after a few photos.  It always burns without the nose cone.  How can something so visually compelling be so useless?  The nose cone always gets soft, depending on the incense brand.  Wider incense makes it hotter & softer.  It might be slowly flowing down over the rigid epoxy over time. 

    There might be a 2nd metal cylinder which goes between the hot section & the plastic section to block heat. 

    It proved easier to manually drill backflow cones than bother with predrilled cones.  That provides a way to choose between a stronger odor or backflow.

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    Now that we've seen a few booster catches, the idea occurred of having the backflow incense burner hang from a full chopsticks diorama.

    The rear end would be smoking exactly like it just landed.

    The ship needs to be a hair bigger & the hot section needs to be completely detached from the 3D printed material.  The trick is lighting it.  The hot section needs to be fixed before lighting.  Then the printed section needs to close in around it to shield it from wind.  There could be a system where the chopsticks open & close to encase the hot section in a fuselage.  

    It would be manually operated.  The hot section would hang from some scissors between the chopsticks while the 2 halves of the fuselage would be fixed to the chopsticks.

    The launch tower would be replaced by something minimal.  There could be a way to adjust the chopstick height for cleaning ashes.  Burning incense could be like operating a full launch facility.

  • 1st complete burn

    lion mclionhead • 01/02/2024 at 23:31 • 0 comments

    There is a trend in commercial incense burners of having the cone fully exposed instead of trying to make a wind break.  The original reason for the rocket was to use it as a wind break but any wind break seems to make a problematic updraft.  It could still be useful as an exhaust duct.  The latest idea is to chop off the nose & use the cone as the nose.  Then make a cylinder all the way up to the nose fins.  The hot section would be fully enclosed in the cylinder & go down to the tail fins.  This eliminates any room to taper the cylinder into a cone.  The cylinder could be removed from above the tail fins for cleaning. 

    Playing with an aluminum tray some more, it might be good enough with the current amount of holes & just clay securing the hot section & aligning the nose cone.  It just needs a PETG nose cone.

    A brand new PETG model achieved the desired smoke, but still got too soft.  A system of holes right around the cone seems to give the best results.  This cone was manually drilled out. 

    It gets hottest in the corners right above the cone & it seems to depend on the air currents.

    Applied some loctite metal to the trouble spots.  This still got too hot to touch, but it managed to keep the PETG from deforming.  It remanes to be seen how many cycles it survives & if it stays stuck to PETG.  This led to a 1st timelapse of a complete burn.

    So basically, the best backflow starship incense burner lions could make ended up being a non functional nose cone on top of an engine section which outgasses like a real engine section.  The backflow functionality doesn't serve any purpose other than visual appeal.   Maybe it could provide some vicarious audience participation during a starship launch.