Typical Aerospace Teams and Tasks. Aerospace Design Teams Emphasizing Conceptual Design

Transcription

1 Typical Aerospace Teams and Tasks W.H. Mason Typical Aerospace Organization Responsibilities of each team member The RFPs in, what now? slide 1 Aerospace Design Teams Emphasizing Conceptual Design Classical Options: Mainly engineers Either sitting in projects or in the home section Pros and Cons either way The clear trend: Include the Customer on the design team - example: the Boeing 777 Work with many more types of people, not just engineers IPPD Teams slide 2

2 Typical Matrix Organization Home Section Project: PD F-16 NASP STOVL ATF CAS 777 Aero Propulsion Flight Controls Structures etc. YOU! You work for a project Your raise comes from your discipline manager slide 3 Possible organization to actually design/build a plane Program Manager Customer Relations Business Operations Configuration Design Project Engineer Systems Eng rg. Vehicle Eng rg. Testing Manufacturing Avionics Aerodynamics Wind tunnel Flight Control Propulsion Flight simulator Weapons Syst. S&C Flight test Structures Systems/Avionics Weights Structural test Observables slide 4

3 The Conceptual Design Team : A Suggested Organization 1. Leader (the keeper of the notebook) 2. Configuration Designer 3. Weights (rock eater) also balance/inertia 4. Vehicle Performance and Mission Analysis 5. Aero Configuration (drag buster) 6. Flight Controls (mechanical as well as handling qualities) 7. Propulsion & Propulsion System Integration 8. Structures/Materials 9. Aircraft Systems 10. Cost and Manufacturing last but not least! slide 5 So What do you do? What each team member contributes Philosophy - what s important about your area? Responsibility - provide results in time for everybody else to use > results must be accurate > realize you ll repeat most analysis many times slide 6

4 Leader Make sure that everything is coordinated, that the person who needs help gets it, and that communications exist between every team member. Set schedules and meet deadlines, working with the configurator and the entire team, establish the vision of the concept. Work with the group to define the decision making process for each part of the design process: What do we need to decide, how will we do it? trade study pro/cons carpet plot etc. Keeps the scorecard: Are you meeting the requirements? Define the risks and risk mitigation relative to technology choices slide 7 Leader (Continued) Keep the design notebook, recording the project history, data and team member commitments. Lead the design review presentation. Make sure that everyone is working on the same airplane, and that the presentations and reports are properly coordinated. If the AIAA design competition is being entered, some other member of the group should be the proposal manager. slide 8

5 Example: Is Everybody Working On the Same Plane? Aero Grp: A single VT! Stability & Control Grp Twin VTs! Two different groups, Two different tail arrangements! - A Real Life True Story - slide 9 Configuration Designer Using CAD, coordinate the requirements into a concept that will fly. A high-quality 3-Vu and Inboard Profile, etc are critical! Provide the group with the design information required to perform analysis of the concept. This means drawings!! Note: initial layout of configs was discussed in class, and is also in Kirschbaum s Aircraft Design Data and Layout Guide Does it Balance? slide 10

6 Weights Estimate weight, cg and inertia of the configuration. Using the concept layout sketch, provide the configuration designer with cg estimate. Include the cg travel with load and mission Use weights equations in Raymer, Torenbeek, Nicolai and Roskam and possibly Niu Generate the standard weight statement. Roskam provides an entire book on weights estimation Niu has a good chapter, and Shevell presents the Douglas wing weight Equation. Get that spreadsheet ready! slide 11 Vehicle Performance and Mission Analysis Develop the mission profile(s). Make sure the airplane can perform the design mission, and define the fallout capability for other missions. This includes operation of the sizing code and generation of carpet plots illustrating the basic sizing in terms of thrust and wing area, and the constraint lines imposed by takeoff, landing, maneuver and accel requirements. Find and use the BCA/BCM. Compute field performance. Make use of information from the: configuration designer regarding geometric definition aero person for the aerodynamic characteristics propulsion person for the basic engine deck data and corrections to account for installation weights person to establish the system weights Note: each one of these people should check the output from sizing to make sure that the data being used is correct. slide 12

7 Aerodynamic Configuration Design and Analysis Define the design drivers. What s the best configuration to do the required mission from an aerodynamics point of view? Ensure the concept is aerodynamically efficient. Think streamlined! Provide the neutral point to the configuration designer (VLM Method, etc.). Estimate zero lift drag, including skin friction, wave, form and misc. drag. FRICTION is available for the skin friction and form drag estimate. Estimate the induced drag, establish a target span e. (LIDRAG, etc.) Select the specific airfoils and design the wing (twist) - details in the second semester preliminary design Make the drag polars, and make sure they are trimmed. Provide estimates of C Lmax (trimmed) for landing and takeoff and define the high lift concept required to achieve that C Lmax Work with Stability and Control: C m0, etc. Does it Trim? slide 13 Handling Qualities, Stability, Control, and Flight Controls Contribute to to the the design concept and philosophy Develop control power requirements (criteria) for the mission Decide how best to meet the requirements, stable or unstable? canard or aft tail, etc. Estimate your design s control power (be able to trim with adequate control margin at critical points in flight envelope). are the control power requirements defined above met? use X-plots to size the tails Assess design stability (use DATCOM or JKayvlm & spreadsheet or equivalent. Note the new Drela VLM). Decide on control system. Meet MIL spec and FAR req ts. for flying qualities. slide 14

8 Propulsion and Propulsion System Integration What the the heck is is the the Engine Deck? Select the type of propulsion system appropriate for the specified design requirements Define the thrust and fuel flow for the engine you selected throughout the flight envelope. As a table, this is known as the Engine Deck from the days when the data was contained in a box of computer cards. Also supply scaling and weight data to the performance guy. (the ONX/OFFX code may be useful) Define the appropriate engine inlet and nozzle, or propeller system for each aircraft concept the group is investigating. Size the inlet capture area or the prop Estimate the installation losses. With the aero and controls guy, define the thrust-drag bookkeeping system. slide 15 Propulsion (cont d) You need to provide the Thrust and sfc characteristics for the entire flight envelope for use in the mission analysis Examples from an AIAA Supplied Data Package Thrust, lbs h sl 10k 20k 30k 40k sfc h sl 10k 20k 30k 40k Mach No Mach No. Note: the info from the engine manufacturer is often non-dimensionalized, the so-called corrected values. Make sure you know what you have! slide 16

9 Structures/Materials Develop an appropriate materials basis cost/complexity example: compare volumetric efficiency of composites vs. wave drag penalty at supersonic speeds Ensure a structural concept that supports the configuration, i.e., identify the load paths for wing, landing gear, tail, etc. Define critical loads requirements for defining structural design basis. Good V-n diagram info is in Torenbeek, Roskam, part V, page 25 for part 25 FAR, and page 38 for the MIL Spec requirement and Niu. Define Operational Limits (Dive speeds, etc.) See Torenbeek, the other parts of Roskam for structural design guidance, and Niu, as well as the overview by Raymer. Size the members (skin, bulkheads, etc.) second semester slide 17 Landing Gear Aircraft Systems Details on systems required in the aircraft Crew station requirements, cockpit layout Passenger and cargo arrangement (volume and weight) Weapons system if appropriate Avionics systems Other mechanical systems (actuators) 1st semester: technology developments and current systems used. Also, concentrate on weight, volume and power requirements slide 18

10 Aircraft Systems (cont d) example from Lockheed of a landing gear trade study: An example of the options for bogie layout investigated by Lockheed during the design of the C-5 aircraft (from the copyrighted AIAA case studies book) slide 19 Aircraft Systems (cont d) example from Lockheed of a loading scheme trade study: From the AIAA C-5 Case Study Viewgraphs, not shipped with the case study until recently slide 20

11 Other Critical Areas Cost estimation: The Critical Area everybody: no decision made without cost consideration Manufacturing planning Proposal Manager Some team members will have to to double up slide 21 Example of Manufacturing Input to B-777 Design reduced cost of an approach used for 30 years! Boeing manufacturing engineers spent hundreds of hours on each plane working on the wing fuselage contour since the 707 but the configuration designers didn t care about the contour details! AIAA Paper slide 22

12 How will you do it? Efficient team interaction Develop a schedule and maintain it! Team decisions: what do we need to do? Individual Analysis using engineering methods, including computer tools Meet to put results together, make a decision slide 23 To Conclude: As we get into the design, we will be meeting - with individual teams (mainly) - a few times: by disciplines to make sure technical activity is under control - if requested Again: stay focused slide 24