3DLabprint P-51D LW-PLA – Build Log summary

[Gil.E]

It's been a while since I printed and built a 3D Printed RC model, however thanks for the inspiration provided by @davidk prolific 3D-printing output, I decided to get back into the game, and attempt finishing this model before the 2024 flying season is over. Here is hoping this won't be an early start to next year's winter build project.

This model is a recent release from 3Dlabprint (May 2023) in LW-PLA. The basic specs are for this P-51D Mustang are below:

Wingspan: 1.4 meter  (55.5 inch)  1:8 scale
Airfoil: LHK508 (modified by designer)
Battery: Li-Pol 2200mAh
Anticipated Full Take-off weight (with battery): 1.5Kg
Motor: 3542 1000KV  (3S setup)
Propeller: two blade 12 x 6 or 4 Blade for scale with degraded performance
ESC: 40-50A/3S


You can find the full user guide including more details, links to guide videos and more here:

https://3dlabprint.com/wp-content/uploads/2023/06/P51D-Mustang-user-guide-04.pdf

Plans for his model can be purchased here:

https://3dlabprint.com/shop/p51d_mustang14/

At $50 USD for the plans/design this is a relatively expensive model, however 3Dlabprints holds at least 2 sales events during the year, one during the holidays seasons, when you can get 20% off all prices or find lower cost value packs (filament pack + design files).
 
Just for perspective, this model size would be the equivalent to E-flite's 1.5m P-51D (BNF) which has a list price of $550 USD, albeit the finish details of the RTF off-the shelf model are still far above what can be done with a 3D printed-build project, but that's for a different discussion. 



 

[Gil.E]

Material used: 3DLabPrint PolyLight Low Weight PLA

There are plenty of LW-PLA colors available directly from the 3DLabPrint, which allows printing and building this model with minimal to no-painting. The color selection even includes a filament color called "Balsa" for traditional builders who might consider transitioning 



I compared a few LW-PLA brands and found the 3DLabprint LW-PLA filaments to be identical in behavior and appearance to the leading brand LW-PLA from ColorFabb.

Both brands should work fine for this model and are available in Grey, Yellow and Red from the following links:

https://colorfabb.us/filaments/materials/pla-filaments/lw-pla/1_75_mm

https://3dlabprint.com/shop/polylight-1-0-lw-pla-filament/ RAY - LW PLA – 3DLabPrint


On the other hand, I recommend avoiding Polymaker's PolyLite LW-PLA, especially when dealing with 3DLabprint's pre-sliced GCODE files for Prusa, as this filament requires further process tuning and didn't print well for me.

The color scheme, right off the printer, should be similar to attached image below, with a red spinner:

[Gil.E]

Printing the Wing Section

The two wings are construction as one 1.4 meter single section, internally broken to 28 printed parts all in LW-PLA. Most of the 28 parts were printed directly from GCODE files that were pre-sliced for Prusa, however a few of the parts required special attention and re-slicing due to issues with printing bed-adhesion issues where parts came loose off the print-bed.




The printing failures, in particular on the small control surfaces which have very narrow cross sections, were resolved by re-slicing the parts with additional brim, which provided additional support material at the bottom of the part for better adhesion  and/or by slowing down the print speeds to avoid toppling the part over when reaching the top end.

[Gil.E]

Wings Construction

The wing section contains a slot for installing optional carbon fiber tube (10mm dimeter, 43 cm long) connecting the two wings, which I opted to install for added rigidity at the center area of the two wings.
 
Aside from the CF tube, there are groove channels running from side to side along the bottom and top side of the wing section.  The instructions indicate these grooves are meant to be filled/stuffed with standard 1.75mm plastic filament (PLA) by snapping it in or inserting it in from one end.

The filaments are locked in and held in by injecting ultrathin CA glue from above. It seems to be a new reinforcement technique introduced by Stephan (3Dlabprint designer) inly recently. I am not sure how effective it is, since the filament is completely flexible it has no effect on the wings rigidity but only serves to add coupling strength the glued wing sections.

I really hope it serves a functional purpose to justify the ugliness 





The design is also making use of  1.75mm PLA filament to serve as (axial) hinges for the ailerons and flaps. It's a nice (cheap) solution however I didn't like this concept. Instead I improvised by using 2mm diameter carbon fiber rods to serve as control surfaces hinges. It feels less flimsy, with no play, and should be much stronger. 



I also added ultra-bright RGB LEDs as navigation lights at the wing tips, which were not part of the original design. opening holes and fishing wires through LW-PLA is quite easy.

[davidk]

Nice clean parts, Gil... the Mustang is looking great.