Draft_SOW_2.5in_HiCap_20160309.pdf

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STATEMENT OF WORK

TWO 2.5-INCH HIGH-CAPACITY (HI CAP) BALANCES FOR

THE ARNOLD ENGINEERING DEVELOPMENT COMPLEX

PROPULSION WIND TUNNEL

March 2016

Distribution Statement D: Distribution authorized to the Department of Defense and U.S. DoD contractors only; Administrative/Operational Use; March 4, 2016. Other requests for this document shall be referred to AEDC/TSTW. Arnold AFB, TN 37389.

Destruction Notice: Destroy by any method that will prevent disclosure of contents or reconstruction of the document.

Information on this page is subject to the distribution statement on the front sheet

This statement of work describes the requirements for two internal balances.

1 Introduction This statement of work describes the requirements for two six-component strain gage balances. The balances will be state of the art in all areas of design, fabrication, gaging, and calibration. The balances will be guaranteed to be free of defects in design, fabrication, and calibration for one year after the balance is delivered. The balance will be interchangeable with balance MC100H-2.5.

2 Balance Load Rating

2.1 Balance Rated Capacity

Normal Force (NF), lbs

Pitching Moment (PM), in·lbs

Side Force (SF), lbs

Yawing Moment (YM), in·lbs

Rolling Moment (RM), in·lbs

Axial Force (AF), lbs

@ 0 PM @ 0 NF @ 0 YM @ 0 SF - -

10,000 32,500 5,000 16,250 18,000 800

(The above loadings are for PM and YM referenced to the balance center)

2.2 Failure Safety Factor

a. The balances shall be designed for a safety factor of at least 3.0 on yield for simultaneous application of the rated full-scale loads on all components if failure would result in the model separating from the sting.

b. The balances shall be designed for a safety factor of at least 2.0 on yield for simultaneous application of the rated full-scale loads on all components if failure would not result in the model separating from the sting.

3 Electrical Characteristics

3.1 Excitation

The vendor shall specify the recommended excitation voltage

Information on this page is subject to the distribution statement on the front sheet

3 Electrical Characteristics (cont.)

3.2 Sensitivity

The minimum output of each component will be 0.6 mV/V. With any exceptions being noted.

3.3 Residual Zero Unbalance

The zero load output of each component shall not be greater than 0.15 mV/V.

3.4 Signal Isolation

The components shall be electrically independent from each other and isolated from ground by at least 5000 megohms at 15 volts.

3.5 Strain Gages

a. All strain gages shall be foil type epoxy bonded, wired into four arm bridges.

b. All gages for a given balance bridge shall be from the same lot number.

c. All gages and connections shall be sealed for moisture and corrosion protection.

d. Bridges may be wired in parallel to improve balance performance.

3.6 Balance Cables

a. Each balance cable shall contain stranded Teflon coated wires twisted in pairs.

Excitation power leads shall be 28 gauge or larger. Excitation sense, monitor, and signal leads shall be 32 gauge or larger with the following color code.

Common voltage will be used for the balance excitation.

Lead Positive Negative

Excitation Power Input (all bridges) Red Black Sense (all bridges) Red Black Monitor (all bridges) Red Black Signal Normal Forward Green Gray Normal Aft Green White Side Forward Green Yellow Side Aft Green Orange Rolling Moment Green Brown Axial Force Green Blue

Information on this page is subject to the distribution statement on the front sheet

3.6 Balance Cables (cont.)

The leads for the temperature sensors shall be clearly identified and distinguishable from the strain gage leads.

b. Each cable shall be a minimum of 120 feet long, and sheathed.

c. Each cable, including the sheath, will be less than 0.50 inches in diameter.

d. The end of the each cable will be terminated with stripped lead wires.

4 Mechanical Specifications

4.1 Deflections are to be held to a minimum. Balance alone deflection data (pitch, yaw and roll angle) will be provided based on manual loadings.

4.2 Angular deflections in the pitch and yaw planes will be less than 3.0 E-4 degrees/ pound and 5.0E-5 degrees / inch-pound, referenced about the balance center.

5 Temperature Requirements

5.1 Temperature Compensation

a. The maximum output of any component shall not exceed 0.1% of full scale at stabilized conditions over the range of 60 to 160°F

b. The sensitivity will not vary more than 0.1% at stabilized conditions over the range of 60 to 160°F.

5.2 Maximum Operating Temperature

The integrity of the balances will not be compromised when exposed to sustained temperatures of 200°F.

5.3 Temperature Sensing Devices

a. Temperature sensing devices shall be installed in order to determine the temperature distribution within the balance. This will require sensors in at least 4 locations on each balance.

b. The temperature sensors shall be of the platinum-resistance type (PRT).

Information on this page is subject to the distribution statement on the front sheet

6 Balance Calibration Requirements

6.1 Loading Requirements

a. The components shall be loaded by applying dead weights in precise locations to achieve full range loads. Each position will be loaded in 4 to 5 increments from zero to a full load condition. Normal and side forces will be loaded at three locations in both the positive and negative directions. Axial force and Roll moment will be loaded in both the positive and negative directions. All other loadings necessary to develop a full second order calibration will be supplied from a manual or machine calibration.

b. All components will be loaded to the maximum condition for 15 minutes to document the creep characteristics.

c. Balance data will be used to derive the equation constants for converting the data to engineering units.

d. The form of the equations and the loading schedule and all raw data will be supplied with the calibration report.

6.2 Calibration Accuracy

The data from the calibration will be used to compute the load values, which will be compared to the applied load. The standard deviation of the errors computed from the back calculated calibration data will be less than 0.15% of Full Range load.

7 Performance Verification

The test results from all loadings shall be included, as well as the data from the temperature performance verification. The constants, equations and standard deviations will also be included. All data will be provided in Excel for Windows file format.

8 Documentation

8.1 The following shall also be included:

a. Electrical diagram with color codes

b. Two copies of the stress analysis to support the safety factor ratings for the balance rated loads and identifying the critical stress areas.

c. Drawings of the assembled balances defining the balance envelope and dimensions for interfaces. This drawing will be releasable by AEDC and not marked as proprietary.

d. CAD model of the balance with sufficient detail to conduct an FEA stress analysis of the balance.

Information on this page is subject to the distribution statement on the front sheet

8 Documentation (cont.)

8.2 All documentation for these balances will be identified as 6-2.50-5.00-2.00M-G and 6-2.50-5.00-2.00M-H

8.3 All documentation provided for the balances shall be marked with the same distribution statement found on the cover of this document.

9 Balance Attachment

9.1 The balances shall have a male taper attachment at the sting end. The taper shall have a gage length of 5.500 inches, a maximum diameter of 2.000 inches, with a taper of 0.125 inches/foot on the diameter, with 85% contact. The taper will match the 3340 standard taper gage

9.2 The balances shall have a cylindrical model attachment 2.500 inches in diameter.

The balances will be secured to the model or calibration body with class RC1 fit pins located in the normal plane.

10 Additional Items

10.1 The balances will be provided with their own carrying case. The cases should provide for the safe handling and storage of the balance, and should be identified as to what balance is stored inside.

10.2 Additional hardware including calibration equipment, and dummy balance, are required. Calibration equipment will be provided in a separate carrying case. The case should provide for the safe handling and storage of the calibration equipment, and should be identified as to what balance is stored inside.

11 Exceptions to the specifications shall be stated per item.