UNIVERSITY OF NOTRE DAME
DEPARTMENT OF AEROSPACE AND MECHANICAL ENGINEERING

AE441: Aerospace Systems Design - Spring 1996

DESIGN FOR ASSEMBLY
A Robust, Low-Cost, Unmanned Airborne Observation Vehicle

The objective of this project will be to gain some insight into the challenges and satisfaction involved in the design of an aircraft system. Particular emphasis will be placed on the role of assembly in manufacturing in the overall system design process. This project will include numerous aspects of the overall system design process and will expose you to many of the conflicting requirements encountered in a system design. The project will allow you to perform a system design study, experience the challenges of working as part of a design/build team, use computer aided manufacturing methods and develop an appreciation for conflicting requirements and limited resources, issues which are always present in a design project.

The primary purpose of this project is to provide insight into the design process and to help you identify those decisions in the design process which most significantly influence the design and manufacturing of the product. In particular there will be significant emphasis placed upon issues related to "design for assembly" since much of the cost associated with the manufacturing process is related to assembly for this class of complex systems. Finally, this project will allow for the opportunity to validate the results of your engineering design efforts through the fabrication and testing of a flightworthy technology demonstrator. Each engineer will be given the opportunity to "fly" their aircraft, in order to begin to appreciate the challenges associated with operations and "training" for new aerospace systems.

OPPORTUNITY

On a daily basis new technologies are being developed which can improve our standard of living if properly integrated into society. Currently it is possible to acquire and transmit relatively high quality video signals using very lightweight cameras and transmitters. Low-cost, reusable and reliable airborne video systems have potential applications in law enforcement, search and rescue and civil defense. Since formal "runways" or dedicated launch facilities may not always be available to these agencies, an aircraft with excellent "short take-off and landing" [STOL] characteristics, benign flying qualities and outstanding confined-space maneuverability is required. This aircraft must be highly reliable, extremely robust and easy to service since these agencies may not have permanent, "profession" system operators.

The project goal will be to design a robust, STOL aircraft which can operate in remote and unprepared locations and carry a miniature video camera and transmitter. Since it is anticipated that this aircraft will be "mass produced," it is a particular concern that the design team develop a concept for which manufacturing costs including materials, tooling, part fabrication and in particular, assembly, will be minimized while still meeting design performance targets.

This electric powered aircraft will be expected meet a variety of performance requirements and operate in all weather conditions. It must demonstrate significant STOL capabilities by being able to operate from "rough," unprepared surfaces. Since this is a "real world" application, all materials and manufacturing costs will be based on the best available data with a proposed January 1, 1997 product introduction and an initial production rate of 100 units per month.

PROJECT REQUIREMENTS

  1. Develop a design proposal for a STOL remote observation aircraft system and associated manufacturing process and assembly facility. The greatest measure of merit will be associated with meeting all stated performance and cost goals and minimizing the per aircraft system cost. The proposal should not only detail the design of the aircraft but must identify the most critical technical, manufacturing and economic factors associated with the design.
  2. Develop a flying prototype for the system described by the proposal. The prototype must be capable of demonstrating the flight worthiness of the basic vehicle and flight control system and be capable of verifying the feasibility and durability of the proposed airplane. The prototype must be a full scale technology demonstrator and validate the payload and range capabilities of the design.
  3. Demonstrate the assembly process for this system by "timing" and evaluating the basic airframe assembly and systems installation. The time required to assemble an aircraft from a complete set of individual parts will be a primary measure of the economic feasibility of the system (this will not include part fabrication).
  4. The design team must also develop a procedure for training of unskilled operators with particular emphasis on takeoff and landing operations. Each member of the team will participate in the ground handling and takeoff performance flight validation.

SPECIAL CONSIDERATIONS AND SYSTEM PERFORMANCE REQUIREMENTS:

  1. The aircraft will be able to carry the airborne video camera and transmitter provided as well as all required power sources. In the actual system the camera must have a remotely variable forward, lateral and down viewing capability but in the technology demonstrator the camera can be fixed and need not demonstrate this capability.
  2. The aircraft must be able to takeoff and climb to a 50 ft altitude when operating from a rough, unprepared surface in a constrained area which is 80 ft by 300 ft in size.
  3. There are two basic missions for this system:
  • Propulsion systems: Propeller driven aircraft using electric propulsion systems are to be considered for their reliability and easy of operation. Alternative propulsion systems can be proposed but approval from management is required.
  • Fuel: rapid charge/discharge ni-cad batteries.
  • Performance on runway surfaces ranging from those similar to the surface in the Loftus center to unprepared "fields" with 2 in. grass ( and bumps) is required.
  • Flight Characteristics and Handling Qualities: Since this will be a utility aircraft which can be used for a variety of applications it should possess very benign handling qualities and be suitable for flight training and novice pilots.
  • Survivability Characteristics: The video system and radio components should be able to survive a worst-case "crash" from any flight condition.
  • The aircraft must be able to be disassembled for shipping in a 2'x1.5'x7' container and must be able to be assembled to a flightworthy condition in 3 minutes.
  • Due to the wide variety of operating environments, the airframe should be considered disposable and component replacement costs determined.
  • Material recycling of all components as well as manufacturing process wastes must be considered and recycling costs quantified and included in the sales price.
  • Effective utilization of automated part fabrication using the 2D CAD/CAM capability and demonstration of its impact on the fabrication process will be considered as "highly significant" in this project.

    SPECIAL CONSIDERATIONS FOR THE TECHNOLOGY DEMONSTRATOR

    The technology demonstrator (prototype) system should satisfy the following:
    1. The assembly of the technology demonstrator will be conducted under special conditions. All parts and subsystems will be fabricated or purchased prior to vehicle assembly. The complete vehicle assembly process will "timed" and this event will be used to assess the feasibility of both the product and the assembly process.
    2. All basic operation will be line-of-sight with a fixed ground based pilot, although automatic stabilization or control or other systems can be considered.
    3. The aircraft must be able to take-off from the ground and land on the ground under its own power.
    4. The in-door prototype flight tests for the Technology Demonstrator will be conducted in the Loftus Center on a closed course. Each member of the design team will be required to attempt to fly the aircraft on a simple demonstration flight. This flight will involve takeoff, climb to clear a 5 ft. obstacle and landing. This demonstration will only take place during the authorized flight testing period and all "training" for this must be conducted prior to that date.
    5. Safety considerations for systems operations are critical. A complete safety assessment for the system is required.
    6. The Technology Demonstrator will be a full sized prototype of the actual design.
    7. The radio control system and the complete propulsion system must be removable and a complete system installation should be able to be accomplished in 20 min.
    8. System control for the flight demonstrator will be a Futaba 6FG radio system with up to 4 S28 servos - additional servos or 7 channel radio system may be available for if justified by the design. Rate gyros may also be available if an automated control or stability augmentation system is considered.
    9. All FAA and FCC regulations for operation of remotely piloted vehicles and others imposed by the course instructor must be complied with.