1/32 Wasp Junior engine

[daveculp]

I ran into a problem with the wires.  The spark plug holes didn't print well, which is common for tiny holes.  They tend to be narrower and shallower than the CAD drawing calls for.  In this case they were nearly closed up, and this caused the wires to collide with the intake ducts.  To fix this I had to drill out the holes with a 0.6mm drill:

 

 

 

 

 

Once the holes were drilled out the cylinders went on with no problems:

 

 

 

 

 

I'll need to drill out the front spark plug holes as well.  I made the wires a little bit longer than necessary just to make sure they reached the hole, and then I figured the hole would take up the extra length.  Of course this only works if there are actual holes   One technique you see applied sometimes is to design the holes with extra width and depth, assuming that the printing process will close it up a bit.  In the case of these tiny spark plug holes I'd probably STILL need to drill out the holes a little.

 

There is supposed to be an oil line connecting each cylinder to its neighbor.  I'll make these out of short lengths of styrene rod (0.6mm diameter looks about right).

 

-- Dave

 

 

[Nighthawk Calling 1]

Amazed at the work that has gone into this Dave, I'll stick to sticking my fingers together with superglue, In ore of your work.

[daveculp]

Here's a shot of the completed engine (minus the cylinder-to-cylinder oil lines that have to be scratch built):

 

 

 

One part that is missing is the hose that runs from underneath the prop shaft and winds to the starboard side of the engine between cylinders.  I don't know what this hose is or where it goes so I left it off.

 

Some parts that will be needed depending on use case:    Firewall, ring mount, exhaust collector ring.

 

 

Here's a link to the STL's:   WaspJr-32.zip

 

License is Freeware.  Do what You want with it.  Let me know if you have any questions.

 

 

-- Dave

 

 

 

 

[LSP_Kevin]

Awesome, Dave.

 

Kev

[daveculp]

Here's an exploded view of the parts (minus the exhaust stacks which I forgot to add to the image).

 

 

 

 

42 parts in all.

[KiwiZac]

Congratulations Dave, she's a beauty! And good on you for making the .stl files free.

[daveculp]

45 minutes ago, KiwiZac said:

Congratulations Dave, she's a beauty! And good on you for making the .stl files free.

 

Thanks, Zac.  Let me know if you run into any problems getting the parts printed.  A reminder - I used Chitubox for slicing (it's free) and the Elegoo Mars 2 Pro for printing.  There might be issues trying to slice with another slicer.  Some slicers are very picky about meshes.  Chitubox is not.

 

-- Dave

[KiwiZac]

I don't have a subject that requires the engine but having the files will make it easier to justify a kit so I can use it! I have a friend with a 3D printer who's happy to print for me at cost...I'll let you know if and when.

[JimRice]

Through EAA I can get a half-price Solidworks annual subscription for $50.  I’ve been meaning to get the the software to learn and use it as well as buying a 3D resin printer.  
 

We are currently building a new house and a barn & (heated and cooled) shop.  In the house I have a large office (for “I love me” stuff from Army career)as well as an upstairs dedicated room for overflow man cave and model and militaria display with space for permanently set-up and available technology; printers, scanners, 8mm movie digitizer, movie projector, slide projector, etc.  I’m thinking I may just have to sneak a quality 3D resin printer into the budget.

Edited March 31, 2022 by JimRice

[daveculp]

14 hours ago, JimRice said:

Through EAA I can get a half-price Solidworks annual subscription for $50.  I’ve been meaning to get the the software to learn and use it as well as buying a 3D resin printer.  
 

We are currently building a new house and a barn & (heated and cooled) shop.  In the house I have a large office (for “I love me” stuff from Army career)as well as an upstairs dedicated room for overflow man cave and model and militaria display with space for permanently set-up and available technology; printers, scanners, 8mm movie digitizer, movie projector, slide projector, etc.  I’m thinking I may just have to sneak a quality 3D resin printer into the budget.

 

 

Jim, I recommend the Elegoo Mars 2 Pro (or whatever is the latest version).  It's cheap and  runs like a top.  I keep it indoors in my office in the Winter, and as soon as the garage gets above 75F or so I move it there.  As for resins, I've tried a bunch of different kinds and have settled on the Elegoo standard grey stuff.  I have not had success with clear resin.  I tried water-washable resin and didn't find any advantage to using it, so went back to IPA-washable.

 

For the slicer app I use the free version of Chitubox.

 

I buy my IPA bottles by the dozen - you'll go through it pretty fast.  I also go through paper towels quickly.  I recommend buying a couple extra resin vats.

 

-- Dave

[JimRice]

Dave,

 

Great info and much appreciated.  I expect I'll be taking the leap soon.  I expect my primary use will be for model building but will also find applications for other things.  I have a 12" swing metal lathe with 48" centers ...and am considering a small mill too.  The 3D printer will be useful for creating prototype parts before milling metal.

[marcelof]

Congratulations Dave, she's a amazing!!!

I am new to 3d printing (only in that), I have a Creality ld-006 (very comfortable) and when I see the cylinders in chitubox, I cannot place a support for the piece between the two heads of it, how have you done it?. T.i.a (sorry for my english)

[daveculp]

4 hours ago, marcelof said:

Congratulations Dave, she's a amazing!!!

I am new to 3d printing (only in that), I have a Creality ld-006 (very comfortable) and when I see the cylinders in chitubox, I cannot place a support for the piece between the two heads of it, how have you done it?. T.i.a (sorry for my english)

 

Thanks marcelof.  For the cylinders I placed them upside-down.  I used a heavy support in the middle and some medium supports around it.  I also added some light supports for the overhangs  and for the oil line on top.

 

 

This just shows the bottom supports.  It doesn't show the light supports for overhangs.

[daveculp]

On 7/27/2022 at 2:23 PM, marcelof said:

Congratulations Dave, she's a amazing!!!

I am new to 3d printing (only in that), I have a Creality ld-006 (very comfortable) and when I see the cylinders in chitubox, I cannot place a support for the piece between the two heads of it, how have you done it?. T.i.a (sorry for my english)

 

I read your post again, and I think this image is what you need.  I don't have any special support settings.  Let me know if this doesn't work for you.

 

 

 

-- Dave

[marcelof]

On 7/31/2022 at 1:06 AM, daveculp said:

 

I read your post again, and I think this image is what you need.  I don't have any special support settings.  Let me know if this doesn't work for you.

 

 

 

-- Dave

Yes, it was what I needed, the support for the oil line, I couldn't get adequate support, I don't know why.
I will try and keep you informed.
thank you dave for your time, you are a gentleman!! greetings.