AQ A031 121 UNCLASSIFIED ARMY AVI*flo TEST BOARt PRODUCT FflRT UtROvEss RUCkfl ALA wy TEST StPe or IMPROVED A*i9 PITCHeLIP* TUSE ASSEeaETC(U) END It
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a r)epar MINI OF Till ARMY UNITED STA T ES ARM Y AV[ATION I Esr IiOA R I) Fort Rucker, Alabama 3 l () \, _ STEI3GT1) subjl:c : SfP io 2ê n i port o1i j fproduct Improvement lest ot Improved AlIl( PitchLink Tii1 Assernhly,f UCATEC OM_ 4oO ( I 1E )IS TRIP UTION Ji r A j 1 RE FE RENCES L r a Letter, AMCPMIRFOT, US Army Materiel Com m and Field Office, 16 January I tk, ) c t Product Improvement Test on Improved Pitch Link Tube Assembly, with 1st lndorsen ent, AMSTEBC, Headquarters, US Army Test and Evaluation Command, l ry 1968 b L :tter, A lcp\1il(t, US Army Materiel Command Field Office, 23 August s )le t: 1 crznination of Test Projects 2 ACK CROtTNf) NCrSsiVe amount of wear and chafing has hr en e xperienced on standard AH I liel er ) t liok tube rod end antirotation lugs, bearing assemblies, and the surlace i ri ors assembly This wear, necessitating replacement ul the assemblies after ppr xiroatel y 5O hours of operation, is attributed to the torsional loads imposed on thepi b L k tube s and to misalignm ent 1 the assem bly In an effo rt reduce m r eliminate this wear, Bell Helicopter Company manulac torm d an improved p itch li nk tube as sembl y and modified the scissors assembly This v;ts submitted to the Iroc uois Project Manager as an Engineering Change Proposal (ECP) The Project Manager desired actual test time on the item prior to approving t b ECP 1 c On 24 January 1968 the US Army Test and Evaluation Command directed the US Army Aviation Test Board (USAAVNTBD) to conduct a product improvement test mt the improved pitchlink tube assembly (reference a) 3 DESCRIPTION OF MATERIEL d The improved pitchlink tube incorporates a lowe r rod end containing two roller biaring a semhlims at the scissors attaching end, whic h eliminates the antirotation tugs and improves the ali gnment of the assembly The roller bearings replace the standard Teflonsurfaced bearings and must be lubricated through four grease fittings Approve d for public release ; distribution unlimited p t73ë7 p
a ST E13G TD SUBJ ECT: Final Report of Test, Product Improvement Test of Improved AHIG Pitch Link Tube Assembly, USATECOM Project Numbe r 460500Il i ) The mo ajicati n ot the scissors consists of a different bushing in the scissors clevis, in order to accommodate the pitchlink tube bearings Photographs of the test items are attached as Inclosure 1 4 OBJECTIVE To determine whether wear and chafing are reduced or eliminated by an im proved AH IG p itchlink tube assembl y and modified scissors assembly 5 SCOPE AND METHOD The USAAVNTBD nducted this Category II productimprovement test at Fort Rucker, Alabama On 21 January 1968 the test items were installed on AHIG Helicopter, serial number 6615257 After accumulating 301 test flight hour s, they were removed and installed on AHlG serial number 6615355 The helicopters were operated in accordance with profiles established for AHIG reliability testing, which included high speed gunnery runs with abrupt pullup maneuvers The test items were inspected in accordance with procedures outlined in TM 55152022120 The test was terminated on 30 August 1968 at the request of the Project Manager (reference b) 6 SUMMARY OF RESULTS a The test items operated 648 hours without excessive wear or chafing on either the lower pitchlink tubes, bearings, or scissors assembly S No unusual or difficult maintenance procedures were encountered during ren ov il or installation of the test items However, the improved pitchlink tube bearings required periodic lubrication whereas the standard pitchlink tube rodend Teflon bearing did not require lubrication 7 DISCUSSION Four standard rodend bearings were replaced on the upper ends of the pitchlink tube s because of bearing wear during this test 8 CONCLUSION The AMIG improved pitchlink tube assembly and modified scissors assembly are a significant improvement over the standard items because of the reduced wear on the p itchlink tube assembly and the elimination of chafing on the scissors assembly 9 RECOMMENDATIONS It is recommended that: a The ECP for the improved pitchlink tube assembly and modified scissors assembl y for AHIC Helicopters he approved 2 A
STEBG TD U lij ECT: Fina l Report mi Test, Product Improvem ent Test 01 Improved AI1IG Pitm Link Tube Assembly, I USATECOM Project Number 4h0500l 1 b Efforts be continued to improve the reliability of the pitchlink tube uppe r roden d hearings FOR TilE PRESIDENT: I loclosure Acting Adjutant DISTRIBUTION: Proj cct Manager, Iroquois U Army Materiel Command ATTN: AMCPMIR P 0 Box 209 St Louis, Missouri 63166 Z5 copies m p a: din General CO ics US Array Test and Evaluation Command ATrN: AMSTEBG Aberdeen Proving Ground, Maryland 21005 t 3 I
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