3D Lab Print Cub - My first 3D printed plane

[Mr NCT]

I'm taking the plunge into 3D printed planes with one that, hopefully, goes smoothly. I have a Prusa MK4 so I started with 3D Lab Print since they work closely with Prusa and bought their filament bundle that has all the LW-PLA, Flexi Light, PETg and PolyAir to complete the plane. I figured why buy whole spools of this stuff if I wasn't sure I'd like it or be able to land well enough to keep it from shattering.

So far I haven't had any problems printing with the LW-PLA using 3D Lab's 3mf files and Prusa Slicer. I have gotten a lot of internal stringing in the fuselage and wing pieces but it cleaned out pretty easy with a long skewer. I tried printing two of the smaller parts, elevator parts, at the same time but the stringing between the parts was pretty bad so for me it's less hassle to print one at a time - I'm not in a big hurry.

Some things I've learned:

• The smooth PEI print sheet holds the LW-PLA fine but allows sharp points to pull up. For sharp points like trailing edges it's a good idea to use some sort of bed adhesive. I'm using Bed Weld and it keeps the points from pulling up.
• For long skinny parts like aileron sections put the long axis in line with the bed movement. I had a couple fail at the top of the print because they were crosswise, in line with the X axis, and wobbled when the bed, Y axis, moved.

I'm almost done with the LW.​

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[ColoFlyer]

I'm taking the plunge into 3D printed planes with one that, hopefully, goes smoothly. I have a Prusa MK4 so I started with 3D Lab Print since they work closely with Prusa and bought their filament bundle that has all the LW-PLA, Flexi Light, PETg and PolyAir to complete the plane. I figured why buy whole spools of this stuff if I wasn't sure I'd like it or be able to land well enough to keep it from shattering.

So far I haven't had any problems printing with the LW-PLA using 3D Lab's 3mf files and Prusa Slicer. I have gotten a lot of internal stringing in the fuselage and wing pieces but it cleaned out pretty easy with a long skewer. I tried printing two of the smaller parts, elevator parts, at the same time but the stringing between the parts was pretty bad so for me it's less hassle to print one at a time - I'm not in a big hurry.

Some things I've learned:

• The smooth PEI print sheet holds the LW-PLA fine but allows sharp points to pull up. For sharp points like trailing edges it's a good idea to use some sort of bed adhesive. I'm using Bed Weld and it keeps the points from pulling up.
• For long skinny parts like aileron sections put the long axis in line with the bed movement. I had a couple fail at the top of the print because they were crosswise, in line with the X axis, and wobbled when the bed, Y axis, moved.

I'm almost done with the LW.​

That is a really good plane to start with. Prints well and fly's great.
I don't always spend the time cleaning out the stringing inside alot of the parts like the wing unless they need to be cleaned to get them to fit together. I don't think the stringing inside adds that much weight on the LW-PLA and it maybe adds a little strength here and there.

I agree with the stringing between parts when you print more than one piece at a time, so I generally only print one part at a time.

Also, on long skinny parts like the ailerons or elevator, I will usually put on a brim of like 10 lines. That keeps the part and the sharp corners down and the brim is easy to remove.

Did you see Troy Macmillan's build video on you tube?

 

[Mr NCT]

Hadn't thought of doing a brim. Good idea, thanks! And yeah, his video helped me make up my mind to try it.

All suggestions welcome!!

 

[Mr NCT]

I've started gluing. The pieces fit together very nicely without much trimming. No surprises so far.

 

[Mr NCT]

Just finished the wing and learned a valuable lesson. There is a groove on the top and bottom of the wing to put either filament or cf rod to strengthen the wing. When you're putting the wing panels together be very sparring in the amount of glue you use near the grooves. It's a pain to clean balls of CA out of the groove once the wing is together. Won't make that mistake again.

 

[ColoFlyer]

Just finished the wing and learned a valuable lesson. There is a groove on the top and bottom of the wing to put either filament or cf rod to strengthen the wing. When you're putting the wing panels together be very sparring in the amount of glue you use near the grooves. It's a pain to clean balls of CA out of the groove once the wing is together. Won't make that mistake again.

Yup, I learned that same lesson but fortunately I noticed that groove on the first 2 pieces of the wing I glued together and made sure I was careful putting the rest of the pieces together. Also, FYI I used a piece of PLA+, like Troy Macmillan shows in his video, and it snapped in the groove to give the wing strength. Carbon fiber rod is just not bendy enough. Once the Filament is installed, the wing becomes surprisingly strong.

 

[Mr NCT]

Yup, I learned that same lesson but fortunately I noticed that groove on the first 2 pieces of the wing I glued together and made sure I was careful putting the rest of the pieces together. Also, FYI I used a piece of PLA+, like Troy Macmillan shows in his video, and it snapped in the groove to give the wing strength. Carbon fiber rod is just not bendy enough. Once the Filament is installed, the wing becomes surprisingly strong.

I thought the same thing about the cf and I had some yellow PLA+.... Great minds think alike.

 

[ColoFlyer]

I thought the same thing about the cf and I had some yellow PLA+.... Great minds think alike.

Here is the Cub I printed. It is printed mostly in LW-PLA. It is surprising how light weight it is. The wheels are even printed in TPU, and work pretty well.

 

[Mr NCT]

It is surprising how light weight it is.

I agree. At first I thought my printer settings were off but it matches the wall thickness and piece weight from 3D Labs. Amazing stuff.

 

[luvmy40]

Tom,
Do you have a link for the build kit? Does it include the .stl files? I'd like have a go at printing a plane on my E5 S1 but, like you I do not want to buy a kilo of LWPLA to see if it works

 

[Mr NCT]

The plane is free. You have to open an account, but hey, they don't charge and haven't been annoying.

Piper J-3 Cub – 3DLabPrint

fully 3D printable R/C model of Spitfire Mk IX

3dlabprint.com

Here's the filament set I bought - yellow for the cub. $20 for the kit, $29 for shipping and it took about a week. It has plenty to print the plane and extra parts. I had to re-do one wing section and a couple of aileron pieces and still have plenty left.

LW FILAMENT MULTIPACK CUB Yellow – 3DLabPrint

Contains all the filaments you need to properly print all parts including tires, details and so on... More than suitable volume for our Piper J-3 CUB, Hurricane, Zero, Bungee Prop or any (1m) LW series plane. Specification: PolyLight 1.0 LW PLA CUB Yellow, active foaming, 330g/111m...

3dlabprint.com

Everything so far has been a breeze. I've imported the model into Prusa slicer to generate the g-code. Worked for everything except the foaming tpu for the tires, that was a mess. Used their supplied g-code and it worked fine. Printing the last tire now.

How's everything going in your world?

 

[luvmy40]

So far, so good! Haven't been able to get much stick time in lately. Got to spend some quality time with the grand kids last week. I'm teaching them the ins and outs of 3D printing with their little EZ ThreeD K1s and the Ender3 V2.

Thanks for the links. I'll look into it this weekend.

 

[Mr NCT]

Finished the Cub except for maiden, crash, repair and decorating . It came in AUW with a 1300 3s battery at 581g. so not too heavy tho it is a little nose heavy. Winds this afternoon are 9W so I'll wait for a calmer day to maiden.

Two minor things:

• The motor mounts pretty far into the fuselage and the motor I used has a threaded shaft for the prop - no way to grip the motor - so I put a ring of sand paper glued to the motor behind the prop and a nut without a nylon keeper so I can hold the prop and still get it tight.
• I sprayed the LW-PLA with acrylic as recommended but the vinyl I used for the windows isn't sticking very well. Probably end up replacing it with a different brand or painting.

It's a fun build, 3d Lab Print did it up right.

 

[ColoFlyer]

Finished the Cub except for maiden, crash, repair and decorating . It came in AUW with a 1300 3s battery at 581g. so not too heavy tho it is a little nose heavy. Winds this afternoon are 9W so I'll wait for a calmer day to maiden.

Two minor things:

• The motor mounts pretty far into the fuselage and the motor I used has a threaded shaft for the prop - no way to grip the motor - so I put a ring of sand paper glued to the motor behind the prop and a nut without a nylon keeper so I can hold the prop and still get it tight.
• I sprayed the LW-PLA with acrylic as recommended but the vinyl I used for the windows isn't sticking very well. Probably end up replacing it with a different brand or painting.

It's a fun build, 3d Lab Print did it up right.

That looks fabulous!! Looking forward to hearing about your maiden.
Mine balances perfectly with either a 1300 3s or some of my smaller 1500 3s.

As far as being a bit nose heavy, it mentions in the user guide instructions (part 10) that a bit nose heavy is suggested, so that may not be a problem for you....

"10. Pilots Please Attention!
For the first flights we recommend setting
the center of gravity to around 5 mm
forward of the CG tag - nose heavy, this
increases the stability (you can use heavier
battery). Increasing expo settings on your
transmitter for elevator and ailerons to 80
% calms response from your stick inputs.
Also you can decrease elevator, rudder and
ailerons deflection to calm down the
plane.
After gaining some confidence you can
balance the plane to the Center of Gravity
marks and set Expos to 60 % as shown in
the video/instructions... this gains back
extra maneuverability."

I didn't use the spray acrylic and so far the decals are sticking. We will see if they hold up.

 

[Mr NCT]

Thanks, of course I only see the flaws. Looking forward to flying it.

 

[Mr NCT]

The weather has been either too rainy or too windy. So I gave the Cub the kiss-of-death by prettying it up before the maiden flight. I'll be sure to post video of the spectacular crash.

 

[LitterBug]

I gave my FT Cub the Kiss of death when I built it. Had a gyro on it to fall back on during maiden, so the kiss of death became HOLY COW!, that cheap gyro fixed all the badness. LOL

 

[Mr NCT]

It's good to have back up

 

[Mr NCT]

Applying vinyl to the LW-PLA:
I'd posted earlier that the vinyl windows didn't stick very well even after applying a couple of coats of acrylic to the LW-PLA. I used a different brand (Oracal) for the markings and it was a little better but peeled off easily by just pulling up a corner. What gave a better adhesion was pulling the vinyl off the backing and spraying the adhesive side with Super 77. It's not a great stick, not like vinyl to vinyl, but it takes more effort to peel it off. I think it's strong enough that it won't blow off.
I used some water slide decal paper to put the Cub logo on the tail. Notice that they're not in the pictures on post #16. After drying overnight they fell off when touched. I put a couple more coats of acrylic on the tail and we'll see how that works. I can always print them on paper and use Super 77 again.

 

[Matthewdupreez]

Applying vinyl to the LW-PLA:
I'd posted earlier that the vinyl windows didn't stick very well even after applying a couple of coats of acrylic to the LW-PLA. I used a different brand (Oracal) for the markings and it was a little better but peeled off easily by just pulling up a corner. What gave a better adhesion was pulling the vinyl off the backing and spraying the adhesive side with Super 77. It's not a great stick, not like vinyl to vinyl, but it takes more effort to peel it off. I think it's strong enough that it won't blow off.
I used some water slide decal paper to put the Cub logo on the tail. Notice that they're not in the pictures on post #16. After drying overnight they fell off when touched. I put a couple more coats of acrylic on the tail and we'll see how that works. I can always print them on paper and use Super 77 again.

use minwax over the lw pla, and then apply the decals