BAK-12 Performance Parameters.pdf

INSTRUMENTATION

7. The following parameters were recorded during the test program:

Parameter Recording Method Accuracy Engaging Speed Laser / Radar +/- 2 kts.

Longitudinal Deceleration Accelerometer +/- 3% Arresting Hook Axial Load Strain Gage Hook +/- 3% Brake Pressure Transducer +/- 3% Runout/Off-Center Distance Painted Deck /

Radar +/- 5 ft

Reel RPM Magnetic sensors +/- 3% (2 magnets at 180° apart)

TEST RESULTS, PERFORMATION, AND ANALYSIS

8. Between December 2010 and July 2011, 36 deadloads were successfully arrested using the BAK-12 at JCTS 5. The BAK-12 successfully arrested deadloads weighing between 25,560 lbs. and 79,920 lbs. at engaging speeds ranging from 74.6 to 157.1 kts. The deadload hook failed to successfully engage the CDP during two (2) events. The engaging speed of both unsuccessful events was in excess of 160 knots. This caused a revision to the test matrix, which required all planned events to target engaging speeds less than or equal to 150 knots. CDP risers were also spaced more closely together during the second phase of the test program to counteract the kink wave caused by the deadload tires passing over the CDP which can cause the cable to momentarily droop in the center causing a hook skip

9. Twelve (12) arrestments were conducted with the baseline brake synchronization pressure setting of 1,100 psi. Twenty-four (24) arrestments were planned at the new brake pressure setting of 1,500 psi with a 15° cam advance. The cam was advanced 75 degrees for a portion of the testing in July 2011, and nine (9) arrestments were conducted while the cam was in the improper position. A total of 15 arrestments were conducted at the new brake pressure setting with the correct 15° cam advance. The collected data is presented as Enclosure (1).

BAK-12 Performance Parameters

13. The charts below show a comparison of hookloads generated by the different hydraulic brake settings when arresting a deadload at a similar weight traveling at a similar speed.

Notice in each chart that the BAK-12 operating with the new settings resulted in a shorter overall runout. The new brake setting and cam position caused the BAK-12 to defuse the energy of the deadload earlier in the arrestment. With the new pressure setting and cam position, higher hookload was experienced in both regions – dynamic and hydraulic – of the arrestment. The peak hookload was experienced earlier in the arrestment. Walkback was not experienced during 25,560 lbs. deadload arrestments with either setting.

Chart 1 – Hookload vs. Runout for site events 8405 & 8424

Chart 2 – Hookload vs. Runout for site events 8407 & 8426

Chart 3 – Hookload vs. Runout for site events 8408 & 8427

14. As chart 4 shows, during a 40,000 lbs. deadload arrestment, the new brake pressure and cam position resulted in a shorter overall runout. With the 1500 psi pressure setting and 15 degree cam advance, higher hookload was experienced in both regions – dynamic and hydraulic – of the arrestment. Enclosure 1 shows that the deadload walked back less with the new settings.

Chart 4 also shows that the BAK-12 operating with the new settings had superior energy absorption early in the arrestment. Notice in chart 4, the hookload was virtually the same at 720 ft. of runout for both events. During event 8421, with the new settings, 8.6 x 106 ft-lbs. of energy was absorbed by the BAK-12 after that point. During event 8412, with the standard brake pressure and cam position, 13.0 x 106 ft-lbs of energy – or >50% more energy – was absorbed after that point. This difference is represented by the shaded region on chart 4.

Chart 4 – Hookload vs. Runout for site events 8412 & 8421

15. Chart 5 shows a comparison of hookload with respect to runout during 50,000 lbs.

deadload arrestments. As was the case with 40,000 lbs. arrestments, the 1,500 psi pressure setting and 15 degree cam advance resulted in shorter overall deadload runout.

Higher hookload was experienced in both regions of the arrestment – dynamic and hydraulic – with the new pressure setting and cam position. As enclosure 1 shows, the deadload walked back less with the new settings.

Notice in chart 5, that the hookload was virtually the same at 830 ft. of runout for both events. During event 8500, with the new brake pressure and cam position, hookload decreased after this point. During event 8414, with the old brake pressure and cam position, hookload remained relatively constant for another 150 ft. of runout before it began to noticeably diminish.

With the increased synchronization settings, 8.5 x 106 ft-lbs of kinetic energy was absorbed by the BAK-12 after 830 ft. of runout. With the old settings, 11.8 x 106 ft-lbs of kinetic energy – or ~39% more energy – was absorbed after that point. This difference is represented by the shaded region on chart 5.

Also, notice that during event 8500, peak hookload occurs at 650 ft. of runout; whereas, during event 8414, hookload did not peak until about 870 ft. of runout. With the 1,100 psi settings, the deadload ceased forward motion less than 300 ft. after peak hookload.

Hookload also dropped from 30,000 to 0 lbs in less than 40 ft at the conclusion of the arrestment. In event 8500, the deadload completed its forward motion about 450 ft. after experiencing peak hydraulic hookload, reducing the abruptness of the stop. The final 30,000 lbs of hookload were absorbed by the BAK-12 in greater than 90 ft. at the conclusion of the arrestment.

Chart 5 – Hookload vs. Runout for site events 8414 & 8500

ENCLOSURE 1:

DATA SHEET FROM

BASELINE TEST WITH BAK-12 BRAKE

SYNCHRONIZATION PRESSURE SET TO 1,100 PSI

BAK-12 Brake Pressure Setting Test for the USAF

D/L ENGAGING HOOKLOAD

Decel (G's)

Max Brake Pressure (psi) Maximum WALKBACK DISTANCE End of HITS

EVENT NUMBER Date WEIGHT SPEED (1000 LBS) (in Hyd Port Stbd REEL RPM RUNOUT WALKBACK VELOCITY OFF-CTR Runout TAPE HITS

PROJECT SITE (LBS) (KTS) DYNAMIC HYDRAULIC region) Peak Peak PORT STBD (FT) (FT) (KTS) (FT) G'S P S CDP

Baseline Testing -------

1 8405 9-Dec-10 25,560 74.6 17.0 12.6 0.45 260 290 347 346 728 0 0 8P 0.00 1 / 1 1

2 8406 " " 104.1 24.1 21.0 0.77 460 495 488 501 847 0 0 6P 0.00 2 / 2 2

3 8407 " " 120.9 30.9 26.3 0.97 610 630 576 579 885 0 0 3P 0.00 3 / 3 3

4 8408 " " 146.3 43.6 34.3 1.30 860 870 705 703 944 0 0 5P 0.00 4 / 4 4

5 8409 " " 163.5 --- HOOK SKIP --- NO ENGAGEMENT ---

6 8410 10-Dec-10 40,340 90.7 23.5 19.9 0.48 415 430 463 464 943 0 0 18P 0.00 5 / 5 5

7 8411 " " 129.0 37.1 33.1 0.82 765 750 674 656 1051 49 3.5 O/C 0.16 6 / 6 6

8 8412 " " 145.6 48.7 42.7 1.05 955 1005 749 743 1069 108 5.1 15P 0.20 7 / 7 7

9 8413 11-Dec-10 50,200 84.6 22.1 20.6 0.41 415 435 439 438 965 0 0 15P 0 8 / 8 8

10 8414 " " 132.3 41.6 41.7 0.82 865 920 698 693 1089 399 8.2 24P 0.27 9 / 9 9

11 8415 " " 153.5 54.2 54.4 1.18 1095 1245 788 804 1122 797 12.8 22P 0.43 10/10 10

12 8416 13-Dec-10 79,920 83.7 25.7 29.1 0.37 405 410 465 465 1110 260 6.7 3P 0.14 11/11 11

13 8417 " " 114.5 NV NV NV 745 730 659 649 ~1235 340+ 10.8 NV NV 12/12 12

ENCLOSURE 2:

DATA SHEET FROM TEST WITH

BAK-12 BRAKE SYNCHRONIZATION PRESSURE

SET TO 1,500 PSI AND 15 DEGREE CAM ADVANCEMENT

D/L ENGAGING HOOKLOAD

Decel (G's)

Max Brake Pressure (psi) Maximum WALKBACK DISTANCE End of HITS

EVENT NUMBER Date WEIGHT SPEED (1000 LBS) (in Hyd Port Stbd REEL RPM RUNOUT WALKBACK VELOCITY OFF-CTR Runout TAPE HITS

PROJECT SITE (LBS) (KTS) DYNAMIC HYDRAULIC region) Peak Peak PORT (KTS) (FT) (FT) (KTS) (FT) G'S P S CDP

Brake synchronization pressure at 1,500 psi with 15 degree cam advance -------

14 8418 14-Dec-10 40,340 84.1 22.1 22.2 0.52 465 475 407 403 824 0 0 15P 0.00 1 / 1 1

15 8419 " " 104.3 31.7 29.4 0.70 705 715 514 520 878 0 0 12P 0.00 2 / 2 2

16 8420 " " 121.3 40.9 36.7 0.89 950 1005 606 590 908 0 0 27P 0.00 3 / 3 3

17 8421 " " 144.4 54.7 49.9 1.22 1300 1495 707 700 965 22 2.7 13P 0.12 4 / 4 4

18 8422 15-Dec-10 " 157.1 68.8 57.9 1.43 1633 1905 785 774 971 81 3.6 9P 0.16 5 / 5 5

19 8423 " " 166.8 --- HOOK SKIP --- NO ENGAGEMENT ---

20 8424 16-Dec-10 25,560 77.3 20.4 15.2 0.62 360 390 356 359 617 0 0 22P 0.00 6 / 6 6

21 8425 " " 100.5 27.9 22.1 0.89 595 605 471 470 699 0 0 7P 0.00 7 / 7 7

22 8426 " " 122.1 35.0 29.3 1.18 835 865 577 575 760 0 0 1P 0.00 8 / 8 8

23 8427 " " 145.2 46.0 41.2 1.63 1230 1460 685 685 800 0 0 4P 0.00 9 / 9 9

33 8495 " " 103.1 34.6 35.0 0.59 856 804 580 572 1079 130 5.7 2P 0.17 19/19 5

34 8496 7-Jul-11 " 125.2 43.6 49.5 0.77 1144 1378 655 654 1125 630 12.8 23P 0.34 1 / 1 6

35 8497 " " 142.0 55.9 64.1 1.00 1621 1858 749 768 1143 808 13.9 20P 0.40 2 / 2 7

36 8498 " 49,965 106.5 40.3 28.5 0.71 780 746 569 560 1050 29 4.1 14P 0.12 3 / 3 8

37 8499 " " 124.7 54.0 40.9 0.88 1155 1202 672 648 1085 104 5.1 9P 0.17 4 / 4 9

38 8500 " " 134.3 79.1 46.8 0.98 1317 1434 700 691 1081 136 5.4 15P 0.18 5 / 5 10 *Note: Events 8486-8494 were conducted with a 1,500psi brake synchronization pressure and 75 degree cam advancement – See Enclosure 2

ENCLOSURE 3:

DATA SHEET FROM TEST WITH

BAK-12 BRAKE SYNCHRONIZATION PRESSURE

SET TO 1,500 PSI AND 75 DEGREE CAM ADVANCEMENT

D/L ENGAGING HOOKLOAD

Decel (G's)

Max Brake Pressure (psi) Maximum WALKBACK DISTANCE End of HITS

EVENT NUMBER Date WEIGHT SPEED (1000 LBS) (in Hyd Port Stbd REEL RPM RUNOUT WALKBACK VELOCITY OFF-CTR Runout TAPE HITS

PROJECT SITE (LBS) (KTS) DYNAMIC HYDRAULIC region) Peak Peak PORT STBD (FT) (FT) (KTS) (FT) G'S P S CDP

Brake synchronization pressure at 1,500 psi with 75 degree cam advance -------

24 8486* 5-Jul-11 49,965 92.6 28.6 25.5 0.55 539 524 479 475 937 82 5.4 4P 0.19 10/10 1

25 8487* " " 114.8 34.7 36.2 0.73 888 941 648 652 969 217 7.1 16P 0.31 11/11 2

26 8488* " " 127.2 41.0 45.3 0.94 1123 1291 676 668 960 222 8.1 17P 0.40 12/12 3

27 8489* " " 142.0 54.7 56.7 1.13 1451 1752 740 763 985 264 8.2 18P 0.41 13/13 4

28 8490* 6-Jul-11 " 148.5 62.6 64.1 1.33 1876 2098 793 783 965 272 7.8 18P 0.38 14/14 5

29 8491* " 64,825 95.1 31.7 35.7 0.55 721 683 530 533 984 88 5.7 2S 0.23 15/15 1

30 8492* " " 111.5 39.2 51.9 0.78 963 1056 615 615 1005 212 7.3 10P 0.34 16/16 2

31 8493* " " 127.2 47.9 66.7 0.99 1293 1485 695 701 1029 276 8.5 13P 0.40 17/17 3

32 8494* " " 135.5 67.7 67.3 1.03 1497 1656 733 741 1032 304 8.3 8P 0.40 18/18 4

ENCLOSURE 4:

HOOKLOAD VS RUNOUT CHARTS

ENCLOSURE 5:

HOOKLOAD VS TIME CHARTS

ENCLOSURE 6:

DECELERATION VS TIME CHARTS

ENCLOSURE 7:

HOOKLOAD VS STARBOARD REEL RPM CHARTS

ENCLOSURE 8:

HOOKLOAD VS PORT REEL RPM CHARTS

ENCLOSURE 9:

PORT & STARBOARD REEL RPM VS RUNOUT CHARTS

ENCLOSURE 10:

PORT & STARBOARD BRAKE PRESSURE VS RUNOUT CHARTS

ENCLOSURE 11:

WALKBACK VELOCITY VS WALKBACK DISTANCE CHARTS

NAWCADLKE-TR238.pdf