March 30, 2025
Description
SIMPLE. FLYING. FUN.
Wespe — a classic rubber-powered flying model.
The development of this model was an engaging and iterative process. The design was refined based on practical flight experience. Version V1 includes the following improvements:
- Improved propeller aerodynamic shape and efficiency
- Optimized propeller design for easier 3D printing and support removal
- Metal propeller axis replaced with a plastic axis
- Slightly increased wing angle of attack
- Elevator added for more precise pitch adjustment
- Simplified fin design
With the optimized propeller, the model shows improved flight performance.
**The print profiles for the obsolete V0 design and for assembly instructions (see attached documents) are available.
"Wespe" is a compact rubber-powered free-flight model for outdoor use in calm weather. The model features an adjustable wing position for precise pitch and CG tuning. The landing gear position can also be adjusted for fine balance setup.
Main specifications:
Wingspan: 406 mm
Length: 410 mm
Wing chord: 60 mm
CG position: 20 mm from wing leading edge (approx. 33%)
Model mass: 35 g (without rubber motor)
Rubber motor length: 260 mm
The model provides a practical introduction to basic aircraft design and flight mechanics.
Model design created and tested using Bambu PLA Basic. Use this material for best results.
Do NOT use PLA Matte, especially for the wing parts. Printed parts may deform after removal from the Plate due to internal material strains after cooling. Use recommended print settings.
Note: The print profile for A1 mini use slightly higher material flow coefficient (1.03 instead of 0.98).
For reliable printing:
The model consists of 22 parts, as shown in Figure.
1 – Propeller, 2 – Spacer, 3 – Prop Axis, 4 – Hub, 5 – A-Beam (3 pcs), 6 – B-Beam, 7 – Circle, 8 – Hook, 9 – Central Bracket, 10 – Double Pin, 11 – Left Wing, 12 – Right Wing, 13 – Big Rib (2 pcs), 14 – Small Rib (2pcs), 15 – Tail, 16 – Fin, 17 – Sting, 18 – Gear Bracket, 19 – Strut (2 pcs), 20 – Wheel (2 pcs), 21 – Pin (2 pcs), 22 – Clamp (4 pcs).
NOTE:
Assemble the Tail (15) and Fin (16).
Insert Prop Axis (3) into Hub (4). Move the axis up and down while rotating it. Repeat this motion until the fit becomes smooth. After adjustment, the axis must rotate freely inside the hub. There must be no resistance or sticking.
Install the Spacer (2) onto the axis. Install the Propeller (1) onto the axis, as shown in the image.
Pay attention to the marker dots on the propeller. The markers must be facing forward. For final installation, press the propeller down while rotating it. Apply small axial force during rotation until fully installed.
For final fixation, slightly melt the tip of the axis for 1–2 seconds, as shown in the image. As an alternative, apply a small amount of glue. After fixation, check that the propeller rotates freely. There must be no binding or friction.
Assemble A-Beam (5) and B-Beam (6) together. Install the Hook (8) between the beams, as shown in the image. Make sure the parts are fully inserted and aligned. Pay attention to the correct orientation of the Hook. Install the rear support Sting (17).
Assemble the front part of the fuselage as shown in the image. Install the Circle (7) between the beams. For installation, use a pencil, pen, or any round tool. Insert the tool through the connector and press it into position.
Connect the front and rear fuselage sections together. Before final assembly, install the Clamps (22) onto the beams, as shown in the image. Slide the clamps into position along the beams. Make sure all parts are aligned before completing the assembly. Fix the beam part together with glue.
Connect the assembled tail unit to the assembled fuselage. Fix with glue.
Install the assembled hub with propeller onto the fuselage. Insert the hub into the front mount of the fuselage. Pay attention to the orientation mark on the hub. The mark must be facing upward. When installed correctly, the propeller axis is angled downward.
Install the Right Wing (12) into the Central Bracket (9). First insert the front edge, then rotate the wing into position. Install the Left Wing (11) into the central bracket in the same way. Make sure both wings are fully seated. Check that the wings are symmetrical and aligned.
Fix the installed wings using the Double Pin (10). Insert the pin into the holes in the Central Bracket (9). Press until both sides are fully engaged. Make sure the pin is fully inserted and locks both wings in place.
Install the Big Rib (13) first. Insert it into the slots on the wing. Then install the Small Rib (14). Press each rib into place until a light click is felt. During installation, make sure the ribs are oriented correctly relative to the direction of flight. Make sure both ribs are fully seated in the slots and aligned with the wing surface.
Install the assembled wing onto the upper beam of the fuselage. Position the wing approximately in the middle of fuselage length. Secure the wing using the Clamps (22). Slide the clamps into position from both sides, as shown in the image.
Assemble the Landing Gear as shown in the image. Install the gear struts into the bracket.
Apply glue during installation to secure the struts. Install the assembled landing gear onto the lower beam of the fuselage in the front section. Fix the landing gear using the Clamps (22).
The assembled model is shown in the image. After assembly, check that all parts are symmetrical. Make sure there is no warping or misalignment. Rotate the propeller by hand. The propeller must spin freely without friction.
Flight performance strongly depends on the type and quality of the rubber motor.
The model is designed for Rubber 1.4 × 70 mm (RA009) from Bambu Lab.
As an alternative to RA009 (B), use model aircraft rubber (C) with the same or larger cross-section.
Do not use office rubber bands (A), as shown in the image.
The Rubber Motor length must be 260 mm in the relaxed state. The motor consists of 4 loops of Rubber (RA009). Assemble the rubber motor as shown in the image:
Install the Rubber Motor onto the model as shown in the image. Check the motor length after installation.
The rubber motor must not be too tight. It must also unwind after 10–15 turns. Before the first flight, perform motor pre-conditioning:
For normal operation with RA009 Rubber, wind up the motor 210–230 turns before launch.
Perform the final check of the model. Make sure there is no misalignment or warping. The propeller must rotate freely without excessive friction.
Perform pre-flight balancing of the model. Balancing must always be done with the Rubber Motor installed. Place the model on a balancing stand using the marked points on the wing. The model must be in static balance or have a slight nose-down attitude.
For precise Center of Gravity (CG) adjustment, move the Wing forward or backward. If needed, adjust the position of the Landing Gear as well. Make small adjustments and re-check balance after each change.
A CG Balancing Stand can be printed using the following link:
https://makerworld.com/en/models/912400-model-cg-balancing-stand#profileId-873575
Use this stand for accurate model balancing before flight.
Launch the model outdoors in calm weather. Recommended wind speed: up to 5 km/h (≈1.4 m/s, ≈2.7 knots). Always launch the model directly into the wind.
Final adjustment of model perform in 2 Steps.
Perform initial glide testing without motor power. Launch the model with a slight nose-down angle using a gentle push. The model must not pitch up (stall). A slightly steep glide is acceptable due to propeller drag.
If the model dives strongly:
If the model pitches up (stalls):
Wind the motor clockwise (as shown in the image) to 210–230 turns.
Launch the model horizontally with a gentle push. Adjust the powered flight in the same way as glide testing.
Yaw adjustment is achieved by deflecting the rudder.
Happy Flights and Smooth Landings!
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Standard Digital File License
Arty_SC
