ST4 OWL

ST4 OWL Flying Videos and Pictures

This model is inspired from the Stick Style model. Compared to other ST models, this AUW model has less weight due to its fuselage size. The wings consist of two parts (left wing and right wing) making it easy to transport. The wing control surfaces are ailerons and also flaps. ST4 would be an all around model that you always want to bring with you to the flying field. With WCL around 10 – 11, it is not only good flying it as a sport flying plane but also doing some aerobatic maneuver.

ST4 OWL Flying PlayList

2 Videos

ST4 OWL - 3D Printed RC Plane from OWLplane.com

4:01

ST4 - Stick Style OWL - Coming Soon Q4 - 2021.

2:59

Specification

Try to avoid printing all parts with 0.40mm extrusion width for getting the best experience with the model. If you still want to print with that extrusion width then try to print some parts with LW-PLA, ePLA-LW or PolyLight 1.0 such as stabilizers (at least/recommended). Saving some weight on the stabilizer parts will save significant amount of weight for the battery (nose side) to get the correct CoG.

ST4 OWL videos posted on the youtube were printed with all PLA+ and 0.32mm extrusion width.

Wing Loading : 66.7gr/dm^2.
AUW/Flying Weight : 2300gr (with battery 3300mAh 4s and printed with 0.32mm extrusion width).
Wing Area : 34.5 dm^2.
Wing Cube Loading (WCL) : 11.3.
Flight Performance Category : Sport Aerobatic.
Radio Channels : Throttle, Aileron, Flap, Elevator and Rudder.
Length : 1165mm.
Wing Span : 1510mm.

Click here if you would like to know about WCL (comparing how easy to fly the plane best described by utilizing WCL instead of Wing Loading. The plane with the same Wing Loading is easier to fly with higher Wing Area than smaller one). It can be best described by WCL value.

Spar Requirement:

– Primary Wing Spar : 1 x 12mm OD and 1000mm long fiber carbon tube (Required).

– Secondary Wing Spar : 1 x 8mm OD and 300mm long fiber carbon tube (Optional).

– Horizontal Stabilizer Spar : 1 x 5mm OD and 450 long fiber carbon tube (Optional).

Fiber Carbon/Aluminum Landing Gear Installation (Optional):

– Main landing gear base is provided if you would like to install your own landing gear.

– With the base glued into the fuselage (suggested to use hot glue), you can use screws to attach the landing gear.

– STL and STEP files are provided under “ST4 OWL – SUPPORT” Directory.

Center of Gravity (CoG):

FUSELAGE-0 Long Nose to Make CoG Correction

Weight and Time Estimation:

Following tables show the weight of printed parts, number of required filament rolls and time required to print. The numbers are taken from S3D slicer calculation. From experience, actual numbers show about -5% less than depicted in the table. But the number may vary from printer to printer due to:

– Stepper Jerk value.

– Stepper Acceleration value.

– Steps per unit (either calibrated or uncalibrated)

– Extruder quality/condition.

– Nozzle quality/condition.

– Filament quality/condition.

– Etc.

For sure the relative number are useful when deciding to accept the total strengths or weights when printing. Picking higher strength to some parts are necessary to avoid breaking during high impact landing or sharp maneuver for example.

Here are the summary tables:

Klipper Firmware Does Not Accept “#” / Hash Character

Unfortunately the Klipper firmware does not accept the “#” / hash character when naming the file. More and more 3D printers nowadays and upcoming most likely will use the Klipper firmware where when using previous firmware such as Marlin, Prusa, etc. do not prevent it from processing.

Since our naming convention for our g-code files utilize the “#” character and already since we started the OWLplane, we still keep them until our new release models dated after July 2024 (after BD OWLjet 70mm 6s EDF).

No worry, to use our g-code files, just need to remove the “#” character, that is it !

Fore example :

“FUSELAGE-1 # P3_H15″ replace the file name with “FUSELAGE-1 P3_H15”

Note : no “#” character is used in the new file name.

How To Extract Our Zip Files

Somehow when the folder path is too long, files and directories can not be extracted directly to a destination directory. There is a workaround for this, just follow the guide below. What you need to follow is to double click zip file until you find the directory. From there, double right click to invoke a “copy” command. After that, just paste the directory into your destination directory. That is it !

Update History

No Update for this model yet.

Recommended Setup

Outrunner 3548

17gr Servos for Elevator

Outrunner 3548

17gr Servos for Elevator

Motor Options : 3548 with 790KV/900KV/1100KV motor type (already tested it with 900KV, should work also with 790KV - 1100KV, see options above but not limited to).
Servo Options : 17gr Servos, 4 x for left and right wings and 2 x for stabilizers (see some options above but not limited to).
ESC Options : ESC with 60A, just pick your favorite ESC but make sure that rated at least 60A.
Propeller Size: depending on your motor KV. For 900KV above, tried with 12x6 and also 11x7, it works great (suggestion : choose lower KV to get lower temperature for the same propellers especially when you print the motor mount with PLA and use low quality spinner).
Battery Size : LiPo 4s 2200mAh - 3300mAh (use battery protection case and balancer to get more weight if necessary that can be found in our library page or download form the link below)..

Battery Protector and/or Weight Balancer Holder for 2200mAh 3s/4s and 3300mAh 4s Battery:

One of challenges in 3D printed plane is where it has a wide range of possible total weight result. For example, the plane printed with 0.40mm comparing to 0.32mm extrusion width may end up the CoG moved about 2cm – 3cm backward with using the same battery. You may need to move the battery forward or add more weight at the nose to get back the CoG to its previous location. To solve this issue at the same time protecting your battery, the following STL files are created for your 2200mAh 3s/4s and 3300mAh 4s. Feel free to download and use the files (G-code files are also provided for Bowden or Direct Drive setup including STEP files).

Download Battery Protector and/or Weight Balancer

Tools and Materials

Printer, in general 200mm x 200mm x 200mm (W x L x H) for all OWLplane Models.
Filament such as PLA, ABS, HIPS and ASA (do not use silk PLA, it tends to be very weak in layer to layer adhesion).
CA glue with accelerator. Use thick glue to join surface to surface. Use thin CA glue for coating the joint surface areas.
Velcro sticker/polyester hook and loop peel-n-stick self-adhesive for locking the battery.
Fine sandpaper.
Sharp knife.
Screwdriver and/or allen wrench for chosen screws/bolts.
Pliers, needle-nose pliers, nippers.
Steel bolt cutter.
Dremel/rotary tool for cutting carbon fiber tubes and rod with more than 2.5mm.
Electric drill, its drill-bit size from 1.5mm - 5mm and step cone drill.
Propeller shaft reamer or hole puncher reamer.

PLA, ABS, ASA or HIPS filaments

hook and loop peel-n-stick self-adhesive

dremel

cutter

push rod and lighter matches

knife, drill, reamer, sandpaper

mini electric drill or screwdriver

pagoda drill

OWLplane Printers (for your ref.)

See figures below some printers used, created, developed and modified by OWLplane. Two group printers are set, the first one is utilized only for printing PLA/PLA+ and the other one is utilized to print with ABS, ASA and HIPS filaments (the one with enclosures). Just hover onto the figures to find more information about them.

Modified all Bowden setup printers into Direct Drive but leave Tevo Tornado and Anycubic Mega as is (still in bowden setup).

DIY AM8 and OWLplane Printers

2 Printers designed by OWLplane, the rest from AM8 DIY Design

Original Prusa MK3S+

Put the printer into DIY enclosure, moved PSU and Display outside the enclosure and added small fan for cooling the control board

Creality Ender 3 and 3 Pro

Modified from bowden setup into direct drive for less jam

Anycubic Mega

Replaced the control board to MKS Gen Lv1 due to control board failure, The setup is still bowden

Tevo Tornado

Still in bowden setup

Creality Ender 5

Moved PSU and control board outside the enclosure and it uses enclosure purchased from creality

Hardware Needed

For Fuselage and Hatch :

M3 x 0.5mm thread x 12mm screws with their washers for outrunner motor to motor mount wall - 4x.
Self tapping screw M3x20mm or M2.5x20mm with their washers for (optional) mounting motor wall to the fuselage (Fuselage - N0) - 8x.
Self tapping screw M3x20mm or M2.5x20mm with their washers for (optional) mounting Fuselage-0 to Fuselage-1 - 6x.
Self tapping screw M3x25mm or M2.5x25mm with their washers (optional) for attaching Fuselage Lid - 2x.
4mm OD and 56mm steel long shaft for main wheel axles - 2x.
Landing gear wheel stop set collar 9x4.1mm for main wheel axles - 4x.
2.0mm OD and 36mm steel long shaft for tail wheel axle - 1x.
Landing gear wheel stop set collar 9x2.1mm for tail wheel axles - 1x.
Ballpoint pen spring for Fuselage Hatch - 1x.

For Wings (except the control surfaces):

For Aileron, Flap, Stabilizer, Rudder and Elevator Servos:

1.5mm - 2mm rod for creating flap, aileron, elevator and rudder hinges (ER308L - TIG Stainless Steel Rod).
1.5mm - 2mm rod for flap, aileron, elevator and rudder pushrod (ER308L - TIG Stainless Steel Rod).
Landing gear wheel stop set collar 9x2.1mm for flap, aileron, rudder and elevator - 6x.
Linkage stopper D2.1mm for for flap, aileron, rudder and elevator - 6x.
2.0mm-2.5mm OD shaft for creating pins connecting two parts for aileron, flap and stabilizer.

stop set collar

linkage stopper

pins with their aluminum construction wire

pins, rod,fiber carbon tube

*) Illustration only

Setup for Servo Travel/Throw

Suggested setup for medium travel/thrown are depicted below and you may adjust the setup according to your need.

3D Printed Motor Mount, Propeller Spinner, Collet and Spar

Motor Mount Requirement

Motor mount wall should be 3D printed with more heat resistance filaments such as ABS, ASA or HIPS. If your 3D printer does not have enclosure you may want to try with PETG filament (more heat resistance than PLA/PLA+). In case you still would like to use PLA, please do annealing process (not sure can do for standard PLA), some successful with HT-PLA/Hight Temp-PLA. Click here for you to read about annealing article.

Propeller Spinner and Collet Requirement

OWLplane does not provide STL file for printed propeller spinner due to our concern about strength, shape and uniform weight when spinning at high speed. Not all 3D Printer has really free of skew issues for all their axes. The skew issue generates uneven shape that will lead to problem when spinning. Good spinner should be available in your local hobby store or online store, even that spinner, you still need to balance it before using it.

Spinner and Collet Requirement :

1. 50mm Diameter Size Spinner.

2. 5mm or 4mm Shaft Propeller Collet (check your purchased motor shaft to pick the right size propeller collet).