Eos-0

Eos-0 is the first vehicle in my Eos program: a single-prop UAV with active fin control, designed for testing. A 4 in body carries one lift motor with a 16 to 20 in propeller and four fins in the prop wash that steer it. It is also the first vehicle to fly Kari, the flight computer I am designing for Eos.

The design is one loop: thrust, mass properties and fin forces go into the controls model, the model shows whether the vehicle can perform the maneuvers, and I change the design until it can.

Each fin needs ±20° of deflection, and there is very little space for the linkage that drives it. That space limit shapes the design more than anything else on the vehicle. I size the parts with straightforward load calculations.

Apart from the linkage, the mechanical design is straightforward.

The electronics are built around Kari, a PCB flight computer I am designing for the Eos vehicles. Its sensors are set by what the controls model reasonably needs.

Because of ITAR I can't go into specifics here. The general approach: I model the vehicle in MATLAB (Simulink with the Aerospace and Control toolboxes), put in its numbers (CG, inertias, thrust, and fin forces from CFD) and check whether it can perform the maneuvers I am attempting. Then I change the design, update the numbers and run it again.

The model will later become a pure controls model for the flight computer. For now it is a sanity check on the design.

Thrust

A first estimate of the requirement, iterated with the controls model.

Propeller

16 to 20 in, with an airfoil that is published online.

ESC

Rated for the current the motor draws.

Battery

6S.

Motor

Chosen on kV and price.

CFD gives me three things: the drag, the size of the vanes, and the fin forces that go into the controls model.

Static tests are planned for:

• Thrust
• Motor time constants
• Possibly fin forces

I will build the ground station in Cosmic, my C++ engine, where SF_Telem for Shear Force already runs.