Three-Bearing Swivel Module (3BSM) - 90mm — Reference Guide

At a glance

• EDF size: 90 mm
• Length: 292 mm (not including EDF)
• Print weight: ~170 g
• Transition angle range: 0 – 105°

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.

Vertical takeoff or landing - VTOL - is among the toughest challenges in aeromodelling. This is especially true when you throw ducted fans into the mix. Fortunately, 3D printing is here to help. This three-bearing swivel module (3BSM) model mirrors the design used on the F-35B jet. When coupled with the right electronics and software, you can create ducted fan VTOL models of your own!

Skill meter

Build: While this design is a straightforward configuration to print and assemble, it has numerous intricate assemblies and moving parts. It's best for builders who have prior experience building 3D printed models.

Specifications

Spec	Value
EDF Size	90mm
Length	292mm (not including EDF)
Outlet Diameter	72mm
Print Weight	~170g
Transition Angle Range	0 – 105 Degrees
Yaw Angle Range	+/- 15 degrees
Ring Gear Ratio	8.25:1

Recommended equipment

The following hardware & electronics are required to complete the 3BSM. In addition, you'll need some CA glue and activator, your R/C transmitter and receiver, and a model to install it in!

Power system & avionics

Item	Details
Motor & EDF	FMS 90mm Special Metal EDF for 8S
Servos (3x)	Hitec MD89MW-CAN
Servo Programmer	Hitec DPC-CAN
Control Board	Lofted Aero 3BSM Controller

An electronics pack containing the control board, servos, and programmer at a substantial bundle discount is available from Lofted Aero HERE.

Hardware

Item	Qty	Part
Bearings	48 required	50pcs MR52ZZ Bearings
Bearing Mount Screws	48 required	M2 x 5 Flat Head Screw, 25-pack (x2)
General Assembly Screws	27 required	#2 x 3/16" Tapping Screw, 50-pack
Servo Mount Screws	6 required	#2 x 5/16" Tapping Screw, 100-pack
Servo Mount Washers	6 required	#2 Flat Washer, 100-pack
Control Board Mount Screws	4 required	M3 x 6mm Socket Cap Screw, 100-pack

A convenient hardware pack containing all inserts and fasteners is available from Lofted Aero 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.

1. Choose your printer from the drop-down menu.
2. You'll find pre-prepared filament settings under "Project-inside presets". Use these as a starting point, tuning for your machine if necessary.
3. Similarly, start from the pre-prepared Lofted Aero process settings under "Project-inside presets".

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)

Quality filament

Using good quality filament can be the key to successful thin-wall prints. PLA is the filament of choice for these prints due to its low warp and high interlayer bond strength. While most PLA may seem identical, there's a lot of variation in diameter tolerance, moisture content, pigment consistency, and melting properties. With poor quality filament, you may notice surface imperfections, underextrusion on thin walls, and stringing between interior features. We've had great results with eSun PLA+ (sometimes sold as PLA Pro) and strongly recommend it for printing Lofted Aero models.

Other printing options

If you choose to try slicing the STL files with a different slicer, there are a few things to keep in mind:

• Nozzle temperature should be 210-220 degrees
• Bed temperature should be 50-60 degrees
• Retraction should be just enough to prevent stringing between features
• Extra length on restart should be just enough to prevent sparse extrusion at layer start

The table below details the recommended slicing settings for each type of part in the 3BSM design.

Components	Relevant Settings
Sections 1-4	3 walls, 100% infill
Nozzle	1 wall, 0% infill
Ring Inserts	2 walls, 50% infill
Ring Gears	1 wall, 100% infill
Pinion Gears	2 walls, 100% infill, 0.10mm layer height, 0.21mm extrusion width, support from build plate only
Servo Mounts	3 walls, 100% infill, 0.2mm layer height

Pinion gear servo spline

The pinion gears must precisely fit the servo output splines and are printed at a lower layer height and extrusion width to enable this. They are designed to fit tightly, though results may vary between printers. If your pinion gears fit too loosely or too tightly, adjust the "X-Y hole compensation" value in increments of +/- 0.05 until you achieve a proper fit.

Assembly

A video guide series outlines assembly of the 3BSM. Watch each video below.

Mechanical assembly

Electronics installation

Software setup

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