slide 1 Announcements/Opportunities Next year’s Aircraft Design class: –We will (again) have a joint team with ME to build and fly a morphing airplane –Send me to –We will have 4 AEs on this team Undergraduate research: - lots of opportunities to help the design class software and do student AIAA papers, see me if you are interested.

slide 2 AOE 3054 Aerospace and Ocean Engineering Instrumentation and Laboratory AOE 3054 Aerospace and Ocean Engineering Instrumentation and Laboratory A Lecture on Aerodynamic Testing W.H. Mason

slide 3 Overview Where you test Why you test How you test Some specifics for your lab

slide 4 The NTF at NASA Langley Hampton, VA Performance: M = 0.2 to 1.20 P T = 1 to 9 atm T T = 77° to 350° Kelvin Feb. 1982

slide 5 The Full Scale Tunnel at NASA Ames 80x120 Foot Test Section 40x80 Foot Test Section Aviation Week & Space Technology, Dec. 7, 1987

slide 6 Information Sources Lot's of introductory material on Aero Test in the manual: read it! The standard reference book: Barlow, Rae and Pope, Low Speed Wind Tunnel Testing

slide 7 Wind Tunnel Testing is Expensive Preparation and planning are required to get into any tunnel: Make pre-test estimates Prepare a pre-test report including a Run Schedule

slide 8 So Will the Computer Eliminate the WT?

slide 9 Key Items Safety, accidents can happen Pretest Planning - the key to success Model Design The Run schedule Typical Tests: - force and moment both performance, stability, and control - pressure distributions - flow diagnostics on and off surface flow visualization

slide 10 Test Hours, F-16 WT Test

slide 11 Research Fighter Configuration (RFC) Visualization with a Tuft Grid Small Model in Grumman Tunnel

slide 12 Another Way To Do Flow Diagnostics Kurt Chankaya, Grumman (now Lockheed)

slide 13 Typical way to put tufts on the wing From Pope and Harper’s text, taken in the Wichita State tunnel

slide 14 Oil Flows for Surface Visualization 1 SC3 Wing, M = 1.62,  = 8° (nominally attached)

slide 15 Oil Flows for Surface Visualization 2 SC3 Wing, M = 1.62,  = 12° (TE flow separation)

slide 16 Laser Light Sheet example Aviation Week & Space Technology, July 29, 1985 Light Sheet from an argon laser, the flow is seeded with an standard smoke generator. Northrop IR & D example of vortex flow over a delta wing configuration. Exhibited at the 36th Paris air show.

slide 17 Model Fabrication: Accuracy important! - drag, under all conditions - low speed near max lift - transonic cruise condition

slide 18 WT model with high LE accuracy Req’ts. Supercritical Conical Camber (SC3) Wing, developed using CFD. The leading edge contour accuracy is critical. Note the arc of the wing along the trailing edge, a sort of “gull shape”

slide 19 Inspecting the Model Leading Edge

slide 20 Fab agrees with designed contour!

slide 21 Simulation Issues Fundamental: Mach number and Reynolds number - Match Mach, do your best on Reynolds, leads to: - transition fixing Test issues: - wall interference, flow angularity, nonuniformity Adjustment from model scale to full scale

slide 22 Tunnel/Mounting Interference

slide 23 Sue Grafton with RFC at NASA Langley

slide 24 RFC in the 30x60 at Langley: static tests

slide 25 Free Flight Setup: A complicated activity

slide 26 RFC Model in Free Flight at Langley

slide 27 The Tunnel

slide 28 The Virginia Tech Stability Tunnel A high quality flowfield - uniform mean flow - low turbulence level - low flow angularity came from NASA in 'x6' test section, 24 ' long 600 hp motor/14' fan 275 fps max speed

slide 29 Virginia Tech Stability Tunnel Layout

slide 30 Velocity Variation in the Test Section

slide 31 Upwash Variation in the Test Section

slide 32 Sidewash Variation in the Test Section

slide 33 Use a Strain Gage Force Balance to Measure Loads Tension change in wire changes resistance You used one before? Assume that the balance is adequately calibrated - we will not check it this year

slide 34 Strain Gages

slide 35 Mechanics for this lab: two weeks 1st week - get ready - check out tunnel, make pretest estimates 2nd week: test! - run the model

slide 36 The Tests! New this year: we have 2 possibilities: 1. The “standard” rectangular wing 2. The Pelikan Tail (from a senior design project) Your choice!

slide 37 Objective: Use Experimental techniques to find aero characteristics of: 1. A rectangular, unswept wing with and w/o transition strips or 2. A novel tail concept almost used on the Boeing JSF, and subsequently adopted by our senior UCAV-N team

slide 38 The Rectangular Wing Model The airfoil: originally a Clark Y, recently modified (thickened) to strengthen the model - How does this change the test estimates?

slide 39 Rectangular Wing Model Airfoil Section

slide 40 Expected Lift Coefficient Variation: Rectangular Wing Model

slide 41 Expected Pitching Moment: Rectangular Wing Model

slide 42 Expected Drag Coefficient Variation: Rectangular Wing Model

slide 43 The Pelikan Tail = HINGE LINE

slide 44 Pelikan Tail Plan View

slide 45 Let those seniors talk? Why should you do this?

slide 46 Wind Tunnel Testing is Fun! Good Luck