TuLam (Toughen up Laminar Technology) is a DLR internal research project with a time span of nearly three years starting in February 2014 and ending in December 2016. It is the successor of the DLR internal research project LamAir (Laminar Aircraft Research). The goal of TuLam is to increase the Technology Readiness Level of the laminarization technology and to further simplify the needed suction system for the Hybrid Laminar Flow Control technology.
The friction loss of laminar airflow is far less than the friction loss of turbulent airflow and is thus the preferred airflow for aircraft wings, tail planes and engine nacelles, where the airflow is turbulent under normal operating conditions for conventional aircrafts. Keeping the airflow laminar during cruise conditions is an important technology for reducing the overall fuel burn of modern aircraft and reaching the ambitious goals of ACARE’s Vision 2020 and Flightpath 2050. For that reason a part of TuLam deals with the investigation of an active Hybrid Laminar Flow Control (HLFC) system for the vertical tail plane of a mid-range aircraft. The chamberless suction nose installed at the leading edge, which was proposed in LamAiR, will be further developed and the whole HLFC-system for the vertical tail plane assessed.
When applying an HLFC-system for the laminarization of aircraft wings and tail planes, a small amount of air has to be sucked-in at the leading edge of the surfaces. By doing that, instability mechanisms which usually trigger the transition from laminar to turbulent flow are delayed to higher chord percentages resulting in a greater laminar flow area. Besides aerodynamic and manufacturing analyses, the system aspects have to be considered, to minimize the system weight, power consumption as well as complexity and thus maximizing the benefits of integrating yet another system into the aircraft. The involved facilities of DLR throughout TuLam are:
The goals, which shall be reached with the project, are:
First of all, tools for the design and assessment of active HLFC-systems are going to be developed, which are not limited to the vertical tail plane as the application surface. The tools shall support the definition of the HLFC-system architecture considering the relevant authorities regulations. Furthermore, the tools shall allow an early estimation of system weight and power consumption of different system architectures early in the design phase. When developing the tools it has to be considered, that they can be integrated into other processes and tools for the overall preliminary aircraft design to further simplify this step.
Additionally, the Institute of Flight Systems is going to design different system architectures for a vertical tail plane equipped with an active HLFC-system using the developed tools. For that, the whole HLFC-system has to be divided into suitable subsystems (like pumps, actuators, sensors,…), which satisfy the requirements. The developed architectures are going to be evaluated based on an integration study using a mid-range aircraft. Due to the simultaneous works in the project ECHO, where an HLFC system has to be developed for the horizontal tail plane of a long-haul aircraft, conclusions can be drawn regarding the transferability of the results.