1/18 LLRV - WIP

[crackerjazz]

OK a little more work done..  I've broken down the frame in nice printable chunks. 

 

 

 

 

 

 

 

 

 

The gimbal frame will hold everything together.    Printable in one piece  -- as long as it's in 1/24 scale  : )  --   so maybe I'll print it in 1/24 for now.

 

 

 

 

Quarter-leg chicken pieces  : )    Also printable in one piece and are structurally sound on their own  : )

 

  

 

This section gave me trouble because the trusses cross.  Couldn't get my rear quarter legs and the rear tray separated without splitting them this way:

 

 

 

 

  

 

 

 

 

  

The quarter legs assemble onto the gimbal frame and the square piece goes on top to  make a nice solid frame.   No jigs to worry about  : )    Still need to break down the rear tray into pieces that are easier to print.  But I'm happy with the main structure breakdown.     

[spaceman]

Greatest respect Joe, 

 

I suspect these linkage struts will be a big challenge for your printer. 

 

Hang in there and keep cool! 

[crackerjazz]

Thanks, Manfred!  : )    Keeping my fingers crossed.

 

I originally wanted to print this thing in one piece but I won't be able to print the bottom rivets and the whole thing wouldn't fit in the build plate, so I to break it down.   I just made sure the top joints don't line up with the bottom joints, so the lower joints are supported by the top piece and vice versa. 

 

 

 

 

 

 

 

 

  

 

 

 

 

Will try to print it in two pieces on the wider build plate next time.

[crackerjazz]

Some progress shots:

 

 

 

Looks like a nightmare to clean up, doesn't it.   Luckily they break off quite easily as long as you remove them before UV-curing the part.   But I still had to fight the urge to just pull them off in bunches -- at some point I was too excited and did just that and broke one of the joints which I had to glue back on. 

 

Hopefully someday printers will be using a different technology that won't need supports to print.   But who would've imagined we'd even be able to print something at home today  : )

 

 

 

 

 

 

 

 

 

  

 

  

 

[spaceman]

OMG Joe, 

and I thought I was just doing crazy stuff like this,   but that seems to be worse than milking mice ... 

But in the end it looks great, it's worth the effort. 

 

Meanwhile you slowly seem to become the Lord of the Printers now, keep it up and hang in there. 

Edited October 5, 2022 by spaceman

[crackerjazz]

Hi Manfred, thanks!  No, man, still learning and have had my fair share of booboos, one fairly recently.  I started up a print and walked away to do some other stuff.  When i came back an hour later to check in on it I noticed the vat was moving up with the build plate but I really paid no heed. I remember telling myself -- hmm ok it's doing it's thing.  It looks strange but it must be nornal.   I  It took me a while to take it all in and realize what was happening.  I saw the thumbscrews were lying right beside the printer which meant the vat wasn't locked and the build plate was trying to peel off the print from the fep and was pulling up the whole vat with it.   Luckily it didn't let go or I would've ended up with a big mess and a smashed LCD screen.   Those yellow covers on the Phrozen printers do have an advantage (over the Elegoo ones with the dark red covers) in that you can monitor the goings-on in there while it prints.

[spaceman]

Great progress, Joe - No pain no gain, and therefore be brave, learning by doing is the best option. 

[CaptKirk]

Brilliant stuff. It must be so satisfying seeing all those tiny details in the CAD drawing come to life on the printer.

[crackerjazz]

Hi CaptKirk, thanks!  It certainly is.  I equate it to the same feeling I get from a mystery novel, though : )  It takes a while for the print to complete and you're never sure how it will turn out.   The leg took 12 hours.   And it's ok, I guess, but I still get those tentpole ridges.   They can be sanded down but I still wish there weren't any.   I notice I get them on beams that are more horizontal or have a shallower angle. 

 

 

What I think happens is that the support rod wicks the resin.   And the resin gets cured along with the layer that's currently curing.   I'm trying another orientation where all trusses are angled and none of them are horizontal.   

 

 

Hopefully I'll get less of them but with the design of the LLRV legs there's always a less angled truss whatever orientation you choose, so i'm just crossing my fingers.    

 

 

This orientation takes 18 hours to do -- got a good 6 hours to go.    We'll see...

[CaptKirk]

Thanks for the additional detail. I guess I'm comparing this (favourably) with the less-than-perfect quality of commercially produced styrene kits, and with the unacceptable-for-scale-model-making quality of my otherwise excellent Ender 3 filament printer. I think your parts look terrific, even with minimal cleanup.

 

Just as a matter of interest, how hard is the clean-up process for the printer itself? Does the unused resin pour nicely back into the bottle? 

[crackerjazz]

Oh ok, the machine cleanup -- I'm assuming everyone hates this step as much as I do : )  Some vats have a channel in the corner to make it easy to pour resin back into the bottle.  Mine doesn't but I normally use a funnel so it's not so bad.  I try to pour the resin back into the bottle through a filter after every print because sometimes cured layers get stuck on the FEP -- those that the support rods weren't able to peel off.  And sometimes little pieces detach from your printed part and end up floating about.  (These tiny debris can cause damage to the FEP or the screen when you start a new print and the build plate homes or presses down to the very first layer so I always make sure the FEP is clean before a new printing session and make sure the resin I pour back into the bottle is clean).     After pouring the resin out I pour some IPA into the vat and try to agitate the remaining resin.  I pour that out and repeat the process a couple times and finally wipe the FEP clean with microfibre cloth.   A bit of  work I know.  Maybe I'll try to pick up one of those gel squeegees to speed things up a little.  By the way sometimes stuck resin clings tightly onto the FEP and can be difficult to remove.  Prying them off with a spatula can scratch the FEP so you have to be careful.  I find it helpful to just leave the IPA in the vat for half an hour or so to loosen them up.  

[spaceman]

Hi Joe,

 

as one can see, this is all a science in itself, but you have the needed patience and perseverance ... 

 

Hold on tight to your dream! 

[crackerjazz]

Hi Manfred, thanks : )

 

I modified the orientation and just as I suspected I get less of those tentpole ridges now for the trusses with steeper angles.   I still get them on the ones with shallower angles.  I made a mistake, though -- I oriented it in such a way that the supports went on the upper (visible) side of the tubes  : )

 

  

 

  

 

 

  

 

 

They still came out pretty good, but I'll try experimenting with a different orientation for the rear legs and see if I can get away with less supports on the trusses with steeper angles.

[CaptKirk]

Thanks for the info! Prints are looking good.

[johnlove_mk_II]

Very nice work.  The second set of legs look great.

[crackerjazz]

Hi, John, thanks!   How are you set for ventilation, by the way?   I'm currently using plant-based resin and print in the basement (no real ventilation to the outside) but I'm thinking about using ABS-like resin. But then I may have to print in the garage and with the weather getting colder that won't be good for both the resin and myself.    I'd really like to continue printing in the basement where I have everything I need.   

 

Some more progress shots.   

 

 

  

 

I used medium thickness supports this time and had to snip off a few at the bottom before prying the whole thing off the build plate because I broke one of the joints that way last time.  

 

  

 

Got all legs printed.  I'm glad to report that I got no ridges along the steeper struts with fewer supports.   I did on the shallower ones just as expected and had to sand them down.   Funny incident -- in the middle of sanding I thought "What would happen if I dropped one of the legs on the floor?"    Not 2 seconds after, I did drop it -- what the mind visualized manifested right away : (    Not so funny was the fact that one of the joints (the ones that connect to the gimbal frame) broke from the fall.  Luckily I still had the initial leg test print which I wasn't planning using because one of its trusses came out of the printer bent (because it had no supports).    I had to cut that truss off and graft a portion from the new leg that had the accident.  

 

I want to experiment eliminating ridges some more by using break-off tabs along those shallow trusses.  The supports can connect to the tabs and after printing I can just break the tabs off.  But maybe I'll do that later on --- I want to print that square part at the top so I can finally connect the legs to the gimbal frame.  Then maybe move on to some nice engine parts : )

Edited October 8, 2022 by crackerjazz

[spaceman]

Congrats Joe, 

 

simply Incredible! 

[crackerjazz]

Thanks, Manfred! : )

 

Was trying out different support setups.   I could get away with those side-pointing boltheads even without support.

 

 

 

  

 

 

Worked also on the square piece on top.  Experimenting on how to eliminate the ridges on the tubes caused by supports.  I put a break-off tab on the bottom of the tube where the supports can connect to.    I've done this before for some small part number tabs on some Cassini parts but wanted to find out how well it would work on longer tubes like this.

 

  

 

 

I did make sure that the tube won't twist around while it prints by putting a few supports in the back of the tube.   I didn't put tabs on all the tubes because I wanted to see the difference.

 

 

 

   

 

 

  

Breaks off nicely.  It leaves a faint line that can be sanded down, which I think is better than sanding down tent-pole ridges.

Not sure if it will work on tougher resins but for the resin I'm using which is quite fragile it works really nicely.  

 

Looks clean here -- because this is the clean side : )

 

  

 

The top piece meshes together with the leg so nicely it stays in place without glue : )   That landing gear could use some glue, though, lol : )

 

  

Tried fitting the gimbal frame but my fingers were shaking from the excitement the gimbal frame slipped from my hands, rolled onto the side of the table and took a dive.  It broke along a pivot joint and is unfortunately under repair.   Really need to try out the ABS-like resin.  If only I had ventilation around here.

 

Edited October 12, 2022 by crackerjazz

[spaceman]

Hey Joe,

 

I'm happy for you that you finally have the opportunity to implement your ingenious 3D modeling skills yourself in 3D print. Practice makes perfect.   

 

And I can see how that spurs you on to keep going, therefore hold on tight to your dreams ...  

 

I'm excited to see what the finished "grasshopper" will look like and can't wait to see it. 

[CaptKirk]

Lovely to watch. So informative & inspiring.

[K2Pete]

By george, I think it's gonna get finished! 

I agree with Capt Kirk and Manfred ... 100%

 

I'm also curious about the 'waste' of material for the supports. Is it calculated by you as 'waste'?

And is this something YOU have to figure out or is this something the software creates automatically?

 

And how many are you gonna print and how much $$$ will you charge? ... just ... you know ... out of curiosity ... !

Pete

[crackerjazz]

Hi CaptKirk, Manfred, Pete, thanks, guys! : )  So much waste, right? Some structures allow for the use of minimal supports but in the case of skeletal trusses like these there seems to be no way around it.  Solidworks shows the volume of just the parts but the slicer software calculates the total volume (supports included) to identify the amount of resin you'll need to pour into the vat.    

 

I'm terrible at judging price -- not sure yet.   I wasn't really planning on selling these initially.   I was doing the 3D work for this (man, was that back in 2014 -- time really flies)  at first to flatten them for cutting sheet styrene for scratchbuilding.   I had Shapeways print a couple shapes that I could vacuform over but I never realized I'd be printing parts myself.   I really have the guys here to thank for providing the guidance and encouragement.   I print parts for Space Cadets just for fun but I can do this on the side while my machines are not busy -- I wouldn't mind making a little money to provide a little motivation  : )   But it'll probably be more like print one, sell that, then do another one if anyone else was interested.   

 

My biggest hurdle, though, is durability.   3D printed parts are known to be brittle and these are no exception -- not sure how these LLRV parts will survive being manhandled at the shipping depots, lol.  I'm using Anycubic Eco and they do have some give to them but I notice that when you drop them they can break.  I'm eyeing ABS-like resin for future LLRV parts but I'm currently printing inside the house and I'm not so sure about the toxicity of the resulting fumes if I print using ABS-like resin.   

 

Glued on the first leg -- Whoopee!!

 

 

I thought I took photos while I mounted each leg but things happened so quickly.  Before I knew it all four legs were on:

 

  

 

 

 

 

 

 

 

 

I notice some slight bowing on the tubes of the square top part -- probably because of unequal curing times on each side, causing the resin to distend on one side.   I remember curing it for 1 min, turning it over and curing for another 2 -- that might be the reason.   If I ever get to it I'll cut out each tube separately and graft in a replacement.  But for now I'll leave the prototype as is and learn what I could.

 

I'm looking at this this thing on my desk and while I'm amazed at how they came up with the design of the structure, I'm still wondering how the aluminum frame on the real aircraft can withstand the weight of the engine in the middle : )   As for this 3d printed frame, I feel like if I add the printed engine, cockpit and electronics tray, fuel tanks and whatnot, this whole thing will just collapse  : )  

 

Oh, one thing I wanted to clarify.  These printed parts are in 1/24 scale.    I haven't gotten back to the 1/18 yet -- parts were too big to easily print -- maybe later on.   I also tried doing the 3D work for a 1/32 but the rods were too thin and the details so small so I chose the middle ground.   And in 1/24 it has some nice chunkiness to it but still small enough to display anywhere.

Edited October 13, 2022 by crackerjazz

[spaceman]

Hey Joe,

 

I take off my hat, and bow to the artist. 

 

Definitely great job so far. 

[crackerjazz]

Thanks, Manfred! : )

 

Some progress on the GE CF700-2V engine aft section parts. Spent some time working on the breakdown and thicknesses to make sure they print.  One of my considerations was to keep the walls as thin as possible to keep the weight down, as I'm not sure how much load the frame can take.   The parts are light, but you never know.  I don't want to end up with an LLRV with splayed legs  : )   I made the walls of these parts thick enough, though, for cleaner support removal.   Many of the supports will be situated on mating surfaces so I have to make sure the supports won't touch the outer edges so they can be removed cleanly.  Also did the necessary clearances so the parts mesh together just right -- neither tight nor loose. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In the grander scheme of things the parts go here:

 

 

 

 

 

 

 

 

 

 

 

Will do some test prints of the parts (in blue).   They assemble well in the software -- hopefully the same goes for the actual assembly. I just realized something.  Turbine blades spin clockwise into the direction of flight - will have to mirror the part : )

[SpacecraftGuy]

One of the coolest and most fun and most inspiring projects I've ever seen. I think there are many of us out here who are almost as excited to see how this turns out as you are. Wonderful stuff!