3.5" 1S Endurance Drone¶

Published: 15 Jul 2026

An experimental 3.5-inch drone optimized for long flight times on a single-cell battery. Its lightweight frame is 3D-printed from PPA-CF.

Design and priorities¶

The frame was designed around low weight, long flight time and a low part count. The camera mount is integrated directly into the frame, avoiding a separate bracket and keeping the build simple.

This is an endurance platform, not a crash frame. The camera is relatively exposed and may be damaged in a crash; that is an intentional trade-off for weight and simplicity. The frame currently weighs about 17 g and the PPA-CF print has made a very good first impression in stiffness and vibration behaviour.

Maximize endurance with a 1S power system
Develop a lightweight, printable PPA-CF frame
Find an efficient combination of motors, propellers and electronics
Document flight time, weight and durability

Current configuration¶

Component	Current setup
Frame	Custom 3D-printed PPA-CF frame, approximately 17 g
Motors	RCinPower 1303, 11,500 KV
Propellers	HQProp 3.5-inch D-Blade for testing; tri-blade also works but feels less efficient and slightly less responsive
Flight controller / ESC board	BetaFPV Matrix 4-in-1 board; exact model designation to be confirmed
Video transmitter	Older HDZero Whoop VTX
Battery	Molicel P45B

Flight and antenna notes¶

The antenna is currently taped to the frame as a temporary solution. A clean mount that keeps it farther away from the frame is still missing. The next frame revision should improve antenna placement for better range and protection, while also providing a cleaner solution for the receiver/radio-link connection.

The current video setup uses an older HDZero Whoop VTX. A future revision is planned with a DJI O4 Lite, but the frame should be adapted first to support proper antenna placement.

Current test results¶

The first measurements already show the direction of the project:

117.55 g take-off weight with a Molicel P45B installed.
24 minutes of flight time achieved during an indoor endurance test with a Molicel P45B.
Intentional frame destruction test performed to develop a practical feel for the printed frame's strength and stiffness. This is an informal destructive test, not a standardized material test.

3.5-inch 1S endurance drone weighing 117.55 grams with a Molicel P45B — **117.55 g take-off weight** The complete 3.5-inch 1S endurance drone weighed with a Molicel P45B installed.

Destroyed printed frame after an intentional strength test — **Intentional frame destruction** The frame after a deliberate break test to get a practical sense of its strength and stiffness.

3.5-inch 1S endurance drone during a 24 minute indoor flight test — **24-minute indoor endurance test** Indoor flight test with a Molicel P45B reaching the reported 24-minute mark.

More data to follow

The component list, frame files, print settings and additional test results will be added during development.