T-38C for 50mm EDF — Build Guide¶
At a glance
- Difficulty: Beginner to build, intermediate to fly
- Wingspan: 575 mm (22.6")
- Length: 1000 mm (39.4")
- Flying weight: 650–750 g (1.4–1.7 lb)
Overview¶
Thank you for purchasing a model by Lofted Aero! 3D printed aircraft are an exciting new segment of the hobby, and we've got no shortage of ideas for new designs. Your support helps us make those reality.
The T-38C is an exciting EDF jet designed to be quick and economical to build without sacrificing design details or scale looks. It delivers impressive performance and handling, with a wide speed range and crisp maneuverability.
Skill meter¶
Build: With a simple design and low parts count, this build is just about as easy as it gets! It is well suited to be an R/C pilot's first transition into 3D printed models.
Flight: This model has good handling characteristics despite its small wings. But it's still a fast, nimble jet that is best flown by pilots of intermediate skill or above.
Specifications¶
| Spec | Value |
|---|---|
| Wingspan | 575mm (22.6") |
| Length | 1000mm (39.4") |
| Wing Area | 9.04dm2 (0.973ft2) |
| Print Weight | ~300g |
| Flying Weight | 650-750g |
| Wing Loading | 72-83g/dm2 (24-27oz/ft2) |
| Airfoil | RG-15 modified |
Recommended equipment¶
The following hardware & electronics are required to complete this model. In addition, you'll need some CA glue and activator, your R/C transmitter and receiver, and a LiPo battery charger.
Power system & avionics¶
| Item | Details |
|---|---|
| EDF | XFly 50mm EDF for 4S Or FMS 50mm EDF for 4S |
| ESC | 40A ESC or Similar |
| Battery | 4S 1300 – 1800mAh LiPo (we use this 4S 1550mAh pack) |
| Servos | 9g Metal Gear (only 2x required) Or FMS 9g Metal Gear with 300mm Wire |
| Servo Extensions | 300mm/12" |
Filament¶
| Use | Filament |
|---|---|
| Foaming LW-PLA for Wings and Tail | 3DLabPrint PolyLight |
| Regular PLA for Accessories | 3DLabPrint PolyAir |
Hardware & structure¶
| Item | Details |
|---|---|
| Wing Spar Tube | Carbon Fiber 6mm x 4mm x 400mm Tube (only 1x required) |
| Stabilator Hinge Tube | Carbon Fiber 4mm x 3mm x 400mm Tube (only 1x required) |
| Pushrods | 1.2mm Pushrods with Linkage Stoppers (only 2x required) |
| Fan and Hatch Mounting Screws | #2 x 3/8" Tapping Screws (or equivalent, only 4x required) |
| Canopy Latch | Pen spring (available here) |
Printing thin-wall models¶
Desktop 3D printers are perfectly capable of producing great-flying R/C models durable enough to withstand hangar rash and general use. However, aircraft designs contain a unique mix of thin surfaces and intricate solid supports that require some practice to print perfectly. Keep the following tips in mind when printing your model.
Slicing with OrcaSlicer¶
The model download includes .3MF project files for OrcaSlicer – a modern, free, and open source slicer with wide support for popular printers and the ability to utilize multiple plates and varying settings within a single project. These project files include print settings tailored to the model as well as filament settings with adjusted temperature and retractions. The provided settings have been tested to suit a wide range of printers – in most cases, no changes should be necessary aside from choosing your printer.
Tutorial video¶
The video below provides a guide for opening the .3MF project files in OrcaSlicer and ensuring the included process and filament settings are applied properly.
Modifiers and per-object settings¶
OrcaSlicer allows per-object modifications to slicing settings, and this method is frequently used in the provided .3MF files. When making settings changes, be mindful of these per-object settings as well as any height range or other modifiers that have been applied to each part. You can use the "View all object's settings" button to quickly view the modifications for all part files in each project.
(example screenshot shown – may not represent this model)
Compatibility note¶
Some versions of OrcaSlicer use "Lateral Lattice" naming to refer to the "2D Lattice" infill pattern. Opening the .3MF files in these versions will produce the following error. Be sure to manually change the infill pattern to either "2D Lattice" "Lateral Lattice" for the relevant parts as appropriate for your OrcaSlicer version.
Other printing options¶
If you'd rather configure and slice the STL files yourself with the software and method of your choice, refer to the table below to configure slicing settings for the different types of parts.
| Parts | Material | Perimeters | Infill | Top/Bottom Layers | Print Temp | Bed Temp |
|---|---|---|---|---|---|---|
| Wings Tail | Foaming LW-PLA | 1 | 3-4% 2D Lattice (Lateral Lattice) | 4/3 | 235C | 56C |
| Fuselage Canopy Fan Hatch | Foaming LW-PLA | 1 | 3-4% Cubic | 4/3 | 235C | 56C |
| Nozzle | PLA | 1 | 0% | 4/3 | 210C | 60C |
| Cheater Inlet Pivot Blocks | PLA | 3 | 15% Grid | 5/4 | 210C | 60C |
| Battery Tray | PLA | 3 | 15% Grid | 4/3 | 210C | 60C |
| All Other Parts | PLA | 3 | 100% | 5/4 | 210C | 60C |
Quality filament¶
Using good quality filament can be the key to successful thin-wall prints. Foaming LW-PLA is the filament of choice for these prints due to its low warp and high interlayer bond strength – but not all LW-PLA is created equally. With poor quality filament, you may notice surface imperfections, underextrusion, or inconsistent foaming. We've had the best results with 3DLabPrint's "PolyLight" LW-PLA and strongly recommend it for printing Lofted Aero models. If it's not available in your region, Colorfabb's LW-PLA is a good substitute. Bambu PLA Aero and eSun LW-PLA will produce acceptable results, but weight will slightly exceed the 3DLabPrint or Colorfabb materials.
Print log¶
Reference print weights for each part.
| Part | Weight |
|---|---|
| LW-PLA | |
| Wing L & R | 20g each |
| Stabilator L & R | 5.3g each |
| Vertical Tail | 12g |
| Fuselage 1 | 4g |
| Fuselage 2 | 20g |
| Fuselage 3 | 31g |
| Fuselage 4 | 47g |
| Fuselage 5 | 35g |
| Fuselage 6 | 29g |
| Fan Hatch 1 | 2.2g |
| Fan Hatch 2 | 2.3g |
| Canopy 1 | 11g |
| Canopy 2 | 7.5g |
| PLA | |
| Stabilator Pivot Blocks | 2.1g each |
| Stabilator Stoppers | 0.4g each |
| Servo Mounts | 1.5g each |
| Battery Tray | 9g |
| Cheater Inlet | 1.5g |
| Hatch Latch | 4g |
| Fan Hatch Tabs | 0.5g each |
| Fan Mount Tabs | 0.6g each |
| EDF Brace (optional) | 2.3g |
| Belly Skid | 2.7g |
| Rear Skids | 2g each |
| Nozzle | 15g |
Joining parts¶
Unless otherwise specified, medium CA and activator are recommended for joining printed parts. In addition, many joints use ~18mm lengths of 1.75mm PLA filament for alignment. Preparing a handful of these ahead of time can help speed up the build.
Fuselage assembly¶
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Using CA and filament alignment guides, glue fuselage sections 5 and 6 together.
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Using the same technique, join fuselage sections 4 and 5.
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Place the hatch latch with a pen spring, then join fuselage 3 to the aft fuselage assembly.
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Glue fuselage 2 to fuselage 3.
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Add fuselage 1 to the nose of the assembly.
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Attach the nozzle, again using pieces of filament to align.
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Prepare the fan area by gluing in the PLA fan mount and hatch mount tabs. Don't worry about orientation – they are symmetrical. Also glue in the servo mount plates.
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Glue the auxiliary inlet cover to the underside of the fuselage.
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Attach the belly skid to the forward fuselage and the aft skids to the rear fuselage.
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Join the two halves of the fan hatch cover.
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Join the two halves of the canopy.
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The fuselage assembly is now complete.
Control surface assembly¶
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Prepare the stabilator pivot blocks by installing pushrod connectors as desired.
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Cut the 4mm carbon fiber stabilator hinge tube to 170mm length.
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Insert and center the stabilator hinge tube in the rear fuselage. Secure it with a few drops of CA, but be careful not to get any glue on the protruding ends.
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Slide the stabilator pivot blocks onto the ends of the tube.
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Glue the stabilator stoppers to the ends of the hinge tube. Ensure that the blocks can still move freely.
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Center and install the servos using self-tapping screws.
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Install pushrods into the servo arms and pivot blocks. Don't tighten them into position just yet.
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Glue the stabilators onto the pivot blocks and tighten the pushrods with the surfaces centered.
Final assembly¶
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Prepare the fan and ESC. Test the fan to ensure it rotates in the correct direction before installing.
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Feed the ESC and wiring into the channel within the fuselage. The ESC will slide quite far forward towards the canopy opening area.
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Install the fan and secure it with two self-tapping screws. Make sure that the wiring rests securely in place under the fan. If your fan doesn't have mounting tabs, use the fan mount brace part to secure.
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Install the fan hatch and secure it with two more self-tapping screws.
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Slide the carbon wing tube into its slot in the fuselage. No need to glue it.
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Glue the wings to the fuselage using the spars and alignment tabs as guidance.
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Glue the battery tray into the cabin area, with a Velcro strap in at least one of the slots. Arrange your receiver and battery as desired.
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Now that the model doesn't need to be upside down anymore, it's a good time to glue on the vertical stabilizer. Assembly is complete!
Pre-flight setup¶
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The recommended CG is marked with grooves on the underside of the wings.
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The neutral position for the stabilator aligns with the geometry of the aft fuselage.
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Adjust control deflections using the suggested throws below. These are measured at the trailing edge of the stabilators where they meet the fuselage. Dual rates are optional depending on your preferences.
Suggested control throws
| Flight Control | Travel | Exponential |
|---|---|---|
| Aileron | 15-20 mm up 15-20 mm down | 20-40% |
| Elevator | 15-20 mm up 10-15 mm down | 30-50% |
Congratulations - you're ready to fly!
Contact us¶
Have a question, issue, or just a cool idea for the next aircraft we should model? Drop us an email at: info@loftedaero.com