This paper investigates the design and implementation of a distributed multi-microcontroller based control system development environment. A DSPIC microcontroller (MCU) based system architecture is established first. The system contains three major parts, namely, sensing and attitude determination section, control section, and ground section. The sensing and attitude determination section consists of four circuit boards (master control board, slave control board, sensor board, and power supply board) with identical size ( ). The sensor boards contains three axes inertial measurement unit (include gyro, accelerometer, and electronic compass) and a GPS receiver. The sensors and the DSPIC MCUs are connected over an I2C (inter-integrated circuit) data bus with the DSPIC on the master control board as the master MCU. Unscented Kalman filter based attitude estimation is incorporated in this embedded system. With incorporation of modular design, combination of the master control board and the slave control board will form the control section of the system. Communications between sections are achieved through UART interface. Because of modular design, the system can be easily expanded to integrate other avionics functions. A model-based state feedback flight control system with time delay is also presented to deal with the inevitable time delay problem of the network control system. The plant model is used to simulate the plant behavior during the periods when sensor data are not available. When the controller receives the sensor data that were transmitted by the sensor a period of time ago, a propagation unit is employed in the control system to propagate the sensor signals instantaneously to the present time. The estimate is then used to update the model that in turn will generate the control signal for the UAV. Computer simulation confirms the success of the model-based design for the distributed multi-chips flight control system.