1、3-9q-45- MIL-T-6053C (USAF) 20 July 1977 SUPERSEDING 26 October 1967 MIL-T-6053B (USAF) MILITARY SPECIFICATION TESTS, IMPACT, SHOCK ABSORBER LANDING GEAR, AIRCRAFT This specification is approved for use by the Department of the Air Force, and is available for use by all Depart- ments and Agencies of
2、 the Department of Defense. - .- l. SCOPE 1.1 This specification covers definition of landing impact tests which are to be conducted on landing gear assemblies including shock absorbers, suggested instrumentation for the tests and required data of the resulting test report. It is intended to standar
3、dize impact test procedures on landing gear shock absorbers and to provide sufficient data to altow evaluation of the design with respect to requirements of MIL-L-8552 and MIL-S-8959 as applicable. 2. APPLICABLE DOCUMENTS 2.1 Issues of documents. The following specifications, of the issue in effect
4、on the date of invitations for bids, form a part of this specification to the extent specified herein. SPECIFICATIONS MILITARY MIL-L-8552 Landing Gear, Aircraft Shock Absorber (Air - Oil Type) MIL-S-8698 Structural Design Requirements, Helicopter MIL-A-8860 Airplane Strength and Rigidity, General Sp
5、ecification for MIL-A-8862 Airplane Strength and Rigidity, Landplane Landing and Ground Handling Loads MIL-A-8868 Airplane Strength and Rigidity, Datd and Reports MIL-S-8959 Spring, Hydraulic, General Specification for STANDARDS MILITARY MIL-STD-831 Test Reports, Preparation of .r f. t I Beneficial
6、comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: ASD/ENESS, Wright-Patterson AFB, OH 45433 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of th
7、is -document or by letter. I I JHlS DOCUMENT CONTAINS Seal failures shall not be cause or rerun of drop test; however, any such failures mustrbe investigated to assure that they are not chronic or that there is not an inherent deficiency in the design. 3.3.1 Design landing tests. In order to validat
8、e the metering characteristics and bottoming capability, conduct a minimum of one drop at each of the test con- ditions outlined in table I. 3.3.1.1 Weights. The weights outlined in table I are derived from the defini- tions presented in Section 6 of MIL-A-8860, or as defined by MIL-S-8698, Section
9、3. 3.3.1.2 Attitudes. The attitudes outlined in table I are derived from the definitions presented in MIL-A-8862. For testing main landing gears (of nose wheel type aircraft), use the two-point attitude with the nose tire just clear of the.ground for the level landing condition. For testing nose lan
10、ding gears of nose gear type aircraft, use the three-point attitude for the level landing condition. No tail down conditions are required or nose gears. 3.3.1.3 Wheel speeds at contact. The wheels shall be spinning in the reverse direction at the time of platform contact. The value of VSL listed in
11、table I is defined in Section 6 of MIL-A-8860 or the VL for autorotative landing at design gross as required by MIL-S-8698, Section 3. The tire radius used for determining wheel rpm shall be the mean undeflecTed radius of the tire, as determined by allowable tolerances and dimensions of the tire, ob
12、tained from the tire performance specification. I/ 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NIL-T-bO53C Lb h 9999906 OLI25bLLI b m me Aircraft rrainer )t her. :lasses lelicopter Drop Nr 1 2 3 4 S 1 2 3 4 5 1 2 3 4 S 6 7 MI L-T- 6053C (USAF)
13、TABLE I. Design landing tests. Weight Condition Landplane Landing Design Gross Weight Landplane Landing Design Gross Weight Maximum Landing Design Gross Weight Maximum Landing Design Gross Weight Maximum Landing Design Gross Weight Landplane Landing Design Gross Weight . Landplane Landing Design Gro
14、ss Weight Maximum Landing Design Gross Weight Maximum Landing Design Gross Weight Maximum Landing Design Gross Weight Basic Design Gross Weight Basic Design Gross Weight Basic Design Gross Weight Basic Design Gross Weight Design Alternate Gross Weight Design Alternate Gross Weight Design Alternate G
15、ross Weight 13. O 13. O a. s a. s 8.5 10. o 10.0 6. O 6.0 6.0 a. o 8.0 8.0 8.0 6. O 6.0 6. O Attitude* Level Tail Down Level Level Tail Down Level Tail Down Level Level Tail Down Level * Level Tail Down (Nose Down) Tail Down . (Nose Down) Level Level Tail Down (Nose Down) Wheel Speed at Contact 1.2
16、VSL 1.0 VSL 1.2 VSL 1.2 VSL 1.0 VSL d 1.2 VSL 1.0 VSL 1.2 VSL 1.2 VSL 1.0 VSL 1.0 VL 0.0 vi 1.0 VL 0.0 VL 1.0 VL 1.0 VL 1.0 VL Maximum yertical Reaction (gs) * * * * * * * * * * * * * *Data supplied by Airframe Contractor. *Flat Strut Drop Test. 3 Provided by IHSNot for ResaleNo reproduction or netw
17、orking permitted without license from IHS-,-,-MIL-T-6053C I6 W 7777906 0425bI5 B W MI5-T-6053C (USAF) 3.3.1.4 Equipment servicing. Except for the flat strut tests outlined in table I, the tire inflation pressure and shock strut servicing pressure shall be those prescribed in the recommended procedur
18、es for operation at aircraft maximum design gross weight. The shock absorber oil level shall be recommended design level. The inflation pressure for the flat strut test will be atmospheric with the strut extended. Plugs with valves will be in a service configuration. 3.3.2 Miscellaneous landing test
19、s. After successful completion of the design tests (3.3.1) the miscellaneous landing tests of table II shall be performed. Upon completion of these tests, there should be no evidence of permanent set or functional impairment. 3.3.2.1 Weights. The weight required in table II is derived from the defin
20、i- tion presented in Section 6 of MIL-A-8860 or-MIL-S=8698, Section 3; - - .- 3.3.2.2 Attitude and wheel contact speeds. See explanation in 3.3.1.2 and 3.3.1.3 respectively, for level attitude. . 3.3.2.3 Equipment servicing. For the tests outlined in table II, the tire inflation pressure shall be th
21、at recommended for operation at aircraft maxi- mum design gross weight. The variations in strut servicing pressure of the two first drops of table II are designed to evaluate the capability of the shock absorbers as required by MIL-A-8862. The last two drops of table II satisfy the testing requireme
22、nts of Section 3 of MIL-L-8552. 3.3.2.4 Strut stowage. If the shock absorber is narmally stowed in such a position that the shock strut centerline has the lower end above a line 10 from horizontal or is stowed in other than the fully extended position, then drops 1, 2, and 3 of the miscellaneous lan
23、ding tests of table II shall be con- . ducted in the following manner: a. Positidn strut with centerline of strut at retracted attitude* relative to horizontal or in the normal stowed extension b. Allow strut to extend and position in landing attitude and hold 120 seconds +20 seconds c. Conduct drop
24、s as prescribed. *If strut purging of dynamic chamber due to retract attitude can be demonstrated, then attitude placement may be eliminated. 3.3.3 Airplane growth tests. After successful completion of miscellaneous tests of 3.5.2, table If, the landing tests of table 111 shall be performed with the
25、 same gear assembly. Upon completion of these tests, there shall be no evidence of functional impairment. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-T-6053C 36 7779706 0425636 T m Aircraf Trainer .r . Ither Drop Nr 1 2 3 - 4 5 6 1 2 3 4 5
26、6 Weight Condition Landplane Landing Landplane Landing Landplane Landing Landplane Landing Landplane tanding Landplane Landing Landplane Landing Landplane Landing Landplane Landing Landplane Landing Landplane Landing Landplane Landing TABLE II. Miscellaneous landing tests. Sink Speed (fPS1 13. O 13.
27、 O 13. O 13. O 13. O 13. O 10. o 10. o 10. o 10. o 10. o 10. o Attitude Level Level Level Level Level Level Level Level Level Level Level Level Wheel Speed l. 2VSL l. 2VSL l. 2VSL 1. 2VSL l. 2VSL l. 2VSL l. 2VSL l. 2VSL 1 2VSL l. 2VSL l. 2VSL l. ZVSL Strut Inflation Pressure (% Rated) 90 110 100 100
28、 100 1 O0 90 110 100 100 100 100 MI L-T- 6053C (USPCF) Oil Volume (S Recommended) . 1 O0 100 100 1 O0 100% minus equivalent 1/2 inch of oleo stroke 100% minus equivalent 1/2 inch of oleo . stroke 100 100 100 100 100% minus equivalent .1/2 inch of oleo stroke 100s minus equivalent 1/2 inch of oleo st
29、roke Remarks * Within 5 min of previous drop * Wsthin 5 min of previous drop t Within S min of previous drop * Within 5 mpeed :fPs) - 8.0 8. o 8.0 8.0 8.0 8. o Attitude Level Level Level Levei Level Level Wheel Speed l. OVL 1. OVL l. OVL l. OVL 1. OVL 1. OVL Strut Inflation Pressure (% Rated) 90 110
30、 100 100 100 100 L Oil Volume (I Recommended) 100 100 100 100 100% minus equivalent inch of oleo stroke 100% minus equivalent inch of oleo stroke -r “ 1/2 * Within 5 min of previous drop * Remarks * Within S min of previous drop * *These drops may be deleted if oil level above the orifice is equal t
31、o at least 125 percent of piston diameter or 5 inches, whichever is less. These drops may also be deleted if the air and oil are physi- cally sepearted (i .e. , Inverted strut, etc.). These drops are only applicable to those shock struts designed In accordance with MIL-L-8552. 3.3.3.1 Weights. Minim
32、um flying weight and landplane design gross weight . outlined in table III are defined in Section 6 of MIL-A-8860 and MIL-S-8698, Section 3. 3.3.3.2 Equipment servicing. For the equivalent energy test outlined in table III, the tire and strut servicing pressures shall be a minimum of 100 percent rat
33、ed values up to and including maximum design gross weights. When the test weight condition exceeds maximum design gross weight, the tire and strut pressures shall be adjusted accordingly in a manner prescribed by the specific component servicing instructions. For multiple-chambered gears requiring s
34、eparate servicing, coordination with the design agency is required and it is normally assumed that the chamber which affects the normal landing conditions is the only one which may be serviced. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-T-
35、bO53C lb m 777770b 0925bLB 3 m MIL-T-6053C (USAF) Type Aircraft rrainer lther iircraft Drop Nr 1 2 3 4 *S - 1 2 3 4 *S Weight Condition .75 x Landplane Landing 1.174 x Landplane Landing 1.397 x Landplane Landing Minimum Flying Weight Minimum Flying Weight .S25 x Landp 1 ane Landing 1.2346 x Landplan
36、e Landing 1.5000 x Landplane Landing linimum Flyiug Weight Yinimum Flying Neight TABLE III. Landing tests. Sink Speed (fPS) 15 12 11 i3. o 13.0 11 9 8.165 10 10 ktitude Level Level Level Lev1 Level Level Level Level Level Level Strut Inflation Pressure (S Rated) 100 See Para. 3.3.3.2 See Para. 3.3.3
37、.2 100 See Para. 3.3.3.3 100 See Para, 3.3.3.2 See Para. 3.3.3.2 100 See Para. 3.3.3.3 - Oil Volume (% Recommended) 100 100 100 100 100 100 100 100 100 100 Remarks Equivalent Energy Test Equivalent Energy Test Equivalent Energy Tost Servicing Evaluation Test Servicing Evaluation Equivalent Energy Te
38、st Equivalent Energy Test Equivalent Energy Test Servicing Evaluation Test Servicing Evaluation Test 7 .- Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Type Aircraft Helicopter Drop Nr TABLE III. Landing tests. - Continued Weight Condition .027 Bas
39、ic Design Gross Weight 1.30 x Basic Design Gross Weight 1.50 x Basic Design Gross Weight Minimum Weight Minimum Weight Minimum Weight Minimum Weight Sink Speed (fPS) 8.0 7.0 6.5 8.0 8.0 8. O 8.0 ittitude Level Level Level Level Level Level Level Wheel Speed l. OVL 1 OVL 1.OVL , l. OVL 1 OVL l. OVL l
40、. OVL Strut Inflation Pressure (% Rated) 100 Adjusted for -G.W. (100%3 min) Adjusted for G.W. 100 150 200 250 li1 Volume (% Iecpmmended) I - “_ MIL-T-bO53C Lb 777770b OLI25b17 5 PIIL-T-6053C (USAF) 1 O0 100 100 1 O0 100 100 Remarks Equivalent Energy Equivalent Energy Equivalent Energy Servicing Eval
41、uation Test Servicing Evaluation Test Servicing Evaluation Test Servicing Evaluation Test Continue until design vertical platform load is reached. 8 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-T-hO53C 16 m 7477706 0425620 I m MTL-T-6055C (USA
42、F-) 3.3.3.3 For the servicing evaluation test, the tfre inflation pressure shall be that recommended for 100 percent usage at maximum design gross weight. The strut servicing pressure shall be increased in increments of 50 percent or less of rated pressure until a maximum static inflation pressure o
43、f 2500 psi or design vertAcal reaction is reached. If a deviation to the 2500 psi servicing pressure limit defined in Section 3 of MIL-L-8552 has been granted, this limit is extended to that permitted in the deviation. 3.3.3.4 Attitude and wheel contact. See explanation in 3.3.1.2 and 3.3.1.3, respe
44、ctively. 3.3.3.5 Design vertical reaction. Design vertical reaction is defined as the load at the wheel associated with a drop at landplane landing weight, level attitude and design sink speed, or basic gross weight. 3.3.4 Reserve energy tests. After completion of the tests outlined in 3.3.1, 3.3.2
45、and 3.3.3, conduct the tests outlined in table IV with the same gear assembly. TABLE IV. Reserve energy tests. I Trainer 1 2 3 Other Aircraft 1 2 l3 “F Helicopter Sink Weight Speed Condition Attitude (fps) Landplane Landing 14.5 Landing Landplane Level 13.5 Level - 9.8 Gross Weight Basic Design Leve
46、l 9.0 Gross Weight Bait Design Level 8.5 Gross Weight Basic Design Level 12.5 Landing Landplane Level 11.5 Landing Landplane LW& i0.s Landing Landplane Level 16.0 . Landing. Landplane Level Strut Inflation Whecl (t Rated) Speed Pressure l. 2VSL 1 I ZVSL 100 1 O0 l. 2VSL 100 l. 2VSL l. 2VSL 100 100 1
47、 2VSL 100 l. OVL 100 l. OVL 100 100 1. OVL Oil Volume (t Recomende& 100 100 100 100 100 100 100 100 100 1 Remarks No Functional Impairment No Functional Impairment Permanent Set- No Failure No Functional Inpairment No Functional Impairment No Failure Permanent Set- No Functional Impairment No Functi
48、onal Impairment Permanent Set - No Failure 1 9 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-T-bO53C lb m 77977Ob 0425b21 3 m “ “I MIL-T-6053C (USAF) 3.3.4.1 Weights. All of the reserve energy tests will be conducted with land- plane landing de
49、sign gross weights, as defined in Section 6 of MIL-A-8860 or MIL-S-8698, Section 3 as applicable. 3.3.4.2 Attitude and wheel speed. See explanation of 3.3.1.2 and 3.3.1.3, respectively. 3.3.4.3 Equipment servicing. Tire and shock absorber inflation pressures shall be required pressures for maximum design gross weight. 3.4 Test witnesses. The procuring activity representative shall be notified in sufficient time so that
