FINAL REVIEW Landing Gear JTP Wear Test Analyses J.D. Schell GE Aircraft Engines HCAT Toronto Meeting Crowne Plaza Hotel August 28-30, 2001

Wear Test Schematics Rod and Bushing wear test.Fretting wear test. Unctd Part (BBS):Block/Seal Bushing/Seal Coated Part (RS) : Shoe Rod

Bushing Rod

Test Matrix Coatings vs Metal Bushings 4340 steel rods 9”x1” –EHC coated, SWA (MIL-STD-1501C, QQ-C-320B) –WC-17Co (Diam 2005) –WC-10Co-4Cr (SM5847) –HVOF by DJ2600 at Ch Pt –All ground to 8 Ra (  -in) Bushings, 64 Ra max –4340 steel, UTS –AMS 4640, Al Ni Bronze –Anodized 2024 Al, SWA (MIL-A-8625, Type 3, Class I) Coatings vs Seals Nitrile Rubber Seals –Grooved 4340 bushing –7214-FT-160-T from Green Tweed (MIL-HDBK-695C) Karon B liner in Al bronze bushing, 0.015” thick layer –Kamatics Corp. –Filled phenolic compound

Test Matrix (cont.)

Wear Measurement Accuracy Wear Volumes from delta weight Vol = Wgt/density Densities of test matls (gm/cc) EHC = =7.83 nitrile=1.27 WC-17Co=12.2 AlNiBR=7.12 Karon B=1.51 WC-Co,Cr=13.6 anodized Al = 3.16 (up to ~3.6 max)

Wear Measurement (cont.) Cleanliness of specimens was an on-going source of error –isolated early occasions where heavy oil and grit in threaded and center point vee were found gave up to 0.15 gm error in weight –improved, but still easily up to 0.01 gm error when missed Due to cleanliness issues, a second method of wear assessment based on visual ratings was developed and used in addition to wgts

Statistical Model Wear Results for 4340 Bushings Max Measurement Error When Poor Cleaning Occurred Measurement Precision (X3)

Visual Appearance of Coated Rods All tested rods visually rated from 1-10 Initial L12 DOE specimens showed wide range of wear scar appeances. Picked least damaged as a 1 and worst damaged as a 10. Selected others as 2, 3, 6, 7, and 8 and adopted these as photostandards for rating rods. All rods laid out and compared side by side with the original rods of the standards (not to photos which follow)

VR 2

VR 3

VR 7

VR10

Chrome and WC-Co

Coatings vs Metal Bushing Summary (Avgs of Orthogonal Arrays) = Data believed to be heavily influenced by measurement errors

Statistical Model Wear Results for 4340 Bushings Max Measurement Error When Poor Cleaning Occurred Measurement Precision (X3)

Statistical Model Wear Results for NiAl Bronze Bushings

Fractional Factorial Fit with Chrome & WC-Co Coatings Estimated Effects and Coefficients for Rod Coating Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C-Ctg D A*B A*C A*D Analysis of Variance for Rod (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total Rod Ctg Wear for L8 Baseline: Cr, WC-Co Differences in wear results are not statistically significant

Fractional Factorial Fit LG L8 1st Half Rep: Cr & WC-Co-Cr Ctgs Estimated Effects and Coefficients for Rod Ctg Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C-Ctg D A*B A*C A*D Analysis of Variance for Rod (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total Ctg Wear for L8 1st Half Rep: Cr, WC-Co-Cr: Differences in wear results are not statistically significant

Bushing Wear with L8 Baseline: Cr,WC-Co: Differences in wear results are not statistically significant Estimated Effects and Coefficients for Bushing Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C D A*B A*C A*D Analysis of Variance for Bushing (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total Ctg

Bushing Wear with L8 1st Half Rep: Cr,WC-Co-Cr Differences in wear results are not statistically significant Estimated Effects and Coefficients for Bushing Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C Rod D Load A*B A*C A*D Analysis of Variance for Bushing (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

Statistical Model Wear Results

Ctg Wear with L8 2nd Half Rep: Cr,WC-Co (4340,Al anodize bushings) Differences in wear results are not statistically significant Estimated Effects and Coefficients for ROD Ctg (coded units) Term Effect Coef StDev Coef T P Constant A B C-Ctg D A*B A*C A*D Analysis of Variance for ROD (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

Bushing Wear with L8 2nd Half Rep: 4340,Al anodize Differences in wear results are not statistically significant Estimated Effects and Coefficients for BUSHING Wear (coded units) Term Effect Coef StDev Coef T P Constant A BUSHING C D A*B A*C A*D Analysis of Variance for BUSHING (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

Coating vs Seals Summary (Avgs of Orthogonal Arrays)

Statistical Model Wear Results for Nitrile Seals in 4340 Bushings

Estimated Effects and Coefficients for ROD CTG Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C D A*B A*C A*D Analysis of Variance for ROD (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total Ctg Wear for L8 3rd Half Rep: Cr, WC-Co Differences in wear results are not statistically significant

Ctg Wear for L8 6th Half Rep: Cr,WCCoCr Differences in wear results are not statistically significant Estimated Effects and Coefficients for ROD Ctg Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C D A*B A*C A*D Analysis of Variance for ROD (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

Nitrile Wear for L8 3rd Half Rep: Cr,WC-Co Differences in wear results ARE statistically significant Estimated Effects and Coefficients for Bushing+Seal (coded units) Term Effect Coef StDev Coef T P Constant A B CTG C Seal D Load A*B A*C A*D Analysis of Variance for Bush+Seal (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

Nitrile Wear for L8 6th Rep: Cr,WC-Co-Cr Differences in wear results are not statistically significant Estimated Effects and Coefficients for Bushing+Seal Wear (coded units) Term Effect Coef StDev Coef T P Constant A B C Seal D A*B A*C A*D Analysis of Variance for Bush+Sea (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

Ctg Wear for L8 4th Rep: Cr,WC-Co (4340 and Karon B Bushings) Differences in wear results are not statistically significant Estimated Effects and Coefficients for BUSHING (coded units) Term Effect Coef StDev Coef T P Constant A B Ctg C Seal D A*B A*C A*D Analysis of Variance for BUSHING (coded units) Source DF Seq SS Adj SS Adj MS F P Main Effects Way Interactions Residual Error Pure Error Total

CONCLUSIONS Coating Wear showed very little difference between Chrome and the HVOF carbides –No statistically significant differences throughout test program Opposed Surface Wear favors Cr –Largest statistical significance with Nitrile seals WC-Co-Cr Favored over WC-Co –When statistically significant differences Karon B Wear best against all coatings