Development and production of 2 antenna holders for DuoLim.

As part of the "DuoLim" project, two DLR research aircraft are to be equipped with an L-band radar system and to fly in a bistatic measurement configuration. This means that the two planes have to fly in more or less narrow formations and require a corresponding overlap area of the areas on the ground that are visible through the antennas. The project started at the end of 2019. This assignment serves the development, production, implementation of flight tests as well as all approval work for 2 antenna holders, including the documentation and approval of the antennas integrated therein.

The DuoLim antenna is an in-house development of the DLR. As part of this assignment, the contractor should support the detailed construction of the antenna. This means that a first antenna design already exists, however, modifications to the antenna itself may be necessary due to this assignment in relation to the given boundary conditions. The antenna design should be coordinated between contractor and client in an iterative process and optimized for airworthiness.

Relevant antenna parameters:

- center frequency: 1.325 GHz;

- bandwidth: 150 MHz;

- Operation: sending and receiving;

- Polarization: Dual linear (horizontal and vertical);

- Transmission power: 1 kW in normal operation;

- Size: installation height: 80 mm; Width: 1020 mm; Depth: 620 mm;

- Weight: approx. 15 kg.

3. Scope of services:

3.1. DuoLim system integration D-CFFU:

- Development (including conceptual design and construction study) and installation of the DuoLim antenna bracket for installation in the lower front aircraft shaft. The antenna should be attached to the SOMAG GSM 4000 Gyro Stabilization Mount and be rotatable around the vertical axis. Details on SOMAG can be found in the manufacturer's data sheet. The antenna mount is mounted on the seat rails and compensates for the aircraft's angle of attack during the flight. In addition to the antenna, an IMU should also be integrated into the antenna bracket;

- Development (including concept design and construction study) and installation of wind deflectors. The attachment should also take place on the seat rails. The wind deflector (spoiler) should not be connected directly to the rotatable antenna bracket;

- Development (including concept design and construction study) and installation of filling elements in the floor shaft. For sealing against air flow;

- Support with the detailed construction of the DuoLim antenna. The first draft comes from the DLR;

- Integration of the required wiring of the antenna up to the defined interface on the Somag GSM 4000;

- Static and dynamic strength tests for the respective internals. Design of the internals against the expected load cases.

3.2. DuoLim system integration D-CODE:

- Development (including conceptual design and construction study) and installation of the DuoLim antenna bracket for installation in the lower front aircraft shaft. The antenna should be attached to the SOMAG GSM 4000 Gyro Stabilization Mount and be rotatable around the vertical axis. Details on SOMAG can be found in the manufacturer's data sheet. The antenna mount is mounted on the seat rails and compensates for the aircraft's angle of attack during the flight. In addition to the antenna, an IMU should also be integrated into the antenna bracket;

- Development (including concept design and construction study) and installation of wind deflectors. The attachment should also take place on the seat rails. The wind deflector (spoiler) should not be connected directly to the rotatable antenna bracket;

- Development (including concept design and construction study) and installation of filling elements in the floor shaft. Sealing against air flow;

- Support with the detailed construction of the DuoLim antenna. The first draft comes from the DLR;

- Integration of the required wiring of the antenna up to the defined interface on the Somag GSM 4000;

- Static and dynamic strength tests for the respective internals. Design of the internals against the expected load cases.

We currently assume that parts of the antenna bracket, wind deflector and filler elements have to be developed specifically for the respective aircraft type, since the shape of the two aircraft differs.

3.3. Flight test Due to the outer location of the DuoLim antenna, flight tests are required to prove the various approval regulations. These are to be developed and carried out together with the DLR FX Flight Test Programs department. The flight tests are commissioned, organized and carried out by the DLR.

The contractor will apply for the permit to fly for the flight tests. The relevant aircraft data and documents (e.g. insurance status) are provided by DLR.

Furthermore, the contractor should carry out the approvals required for the flight test (conformity inspection).

3.4. Admission:

The contractor takes over the two LBA approvals (STCs) for the installation of the antenna brackets on the two aircraft.

3.5. Additional services:

- Creation and delivery of all necessary drawings and delivery of the step models for the production and assembly of the antenna installation;

- Accompanying the manufacturing;

- Components and parts are not part of the order;

- Travel costs to the DLR Oberpfaffenhofen site may not be billed separately;

- The following services are carried out by DLR Flugbetrieb:

—— Determination of the aerodynamic influence of the DuoLim antenna installation on the respective aircraft models and CVE function;

- determination of the aerodynamic loads on the antenna and the wind deflector and CVE function;

—— Conducting the test flights.

4. Further requirements for the contractor:

- The contractor must be certified according to DIN: ISO 9001 / EN9100 and EASA Part 21J.

- A “Design Organization to Design Organization” (DO-DO) must exist between the DLR and the contractor in accordance with the guidelines of the LBA or EASA. If this does not exist, the contractor must guarantee in writing that he can agree this agreement with the DLR development company without increasing the price or the project duration.

- Completion within 24 months of placing the order insofar as the client fulfills the requested services on time. The relevant contributions from the client must have been confirmed by both parties before the order is placed.