Regulations for Acceptance Tests of Aircraft Engines

Provided by Michał "Hiromachi" Czubak
via The Air Force Historical Research Agency

Subject: Regulations for Acceptance Tests of Aircraft Engines.
Administrative Equipment Order (NAIREI HEI) No. 83 (1942), Annexed Volume.
Source: Captured on Saipan, July 1944




Chapter I - Introduction

Chapter II - General Rules

Chapter III - Structural Tests

Chapter IV - Operational Tests


Chapter I - Introduction

Item 1 - The following specify the regulations which concern aircraft engine acceptance tests.

Item 2 - The purpose of aircraft engine acceptance tests is to assess the practical value of the engine's construction, performance, reliability and endurance.

Item 3 - The OinC (Naval Air Headquarters) will specify separate regulations, based on the present ones, for the acceptance tests of special type engines which are not adequately covered by these regulations.

Item 4 - Besides these regulations, separate regulations for aircraft engine construction and repair tests should be used wherever applicable.

Item 5 - Details of test procedure will follow procedures established separately by OinC.

Item 6 - When tests are to be carried out according to these regulations, the OinC will notify the departments concerned.

Item 7 - Acceptance tests conducted under these regulations will be made on the following engines:

Item 8 - Acceptance tests will be subdivided as follows:

Item 9 - The entire acceptance test procedure is to be followed for experimental engines.

Item 10 - Entire or partial test procedure is to be followed for remodeled service type engines as indicated by the OinC.

Item 11 - Acceptance tests will be conducted at the Air Technical Depot as a general practice. Where deemed necessary, part of the acceptance tests may be conducted at the factory.

Item 12 - All factory tests and inspections will be conducted in the presence of a supervising or inspecting official.

Item 13 - Instruments, machines, equipment, and units of measurement used during tests and inspections must be approved by the OinC.

Item 14 - Tests of experimental engines will be conducted on engines for which tests have been completed at the factory. These tests will follow the procedure for tests of engine performance and second operational tests on the same model engine as determined by these regulations.

Item 15 - When the manufacturer desires acceptance tests to be made on an experimental engine, he will submit two copies of the following data along with the application to the OinC, Naval Air Headquarters and forward these copies to the OinC, Air Technical Depot.


Chapter II - General Rules

Item 18 - The rated output of an aircraft engine is the output at rated altitude and rated horsepower (HP). For engines with variable speed superchargers, the rated output at first rated altitude and at rated HP. This applies also to engines equipped with continuous variable pressure (speed) superchargers.

Item 19 - When the rated output of an engine is 300 HP or less, multiples of 5 HP will be used, and when greater than 300 HP, multiples of 10 HP will be used to indicate output.

Item 20 - To indicate various manifold pressures, multiples of 5 millimeters will be used.

Item 21 - To indicate various revolutions per minute (RPM), multiples of 20 or 50 RPM will be used.

Item 22 - To indicate rated altitude, multiples of 200 or 500 meters will be used.

Item 23 - Terms used in the regulations are defined as follows:

Item 24 - As a standard, take-off HP is greater than rated HP at rated altitude.

Item 25 - As a standard, normal maximum manifold pressure is no less than 85 % of the rated manifold pressure.

Item 26 - Take-off RPM is greater than rated RPM.

Item 27 - High speed RPM is no less than 110 % of rated RPM.

Item 28 - Idling speed RPM is no more than 25 % of rated RPM.

Item 29 - Oil temperature permissible for continuous operation is 70 degrees or above at oil pump inlet, while the oil temperature permissible for 30 minutes operation is 85 degrees or above.

Item 30 - Coolant outlet temperature permissible for continuous operation at sea level, using plain water, is 80 degrees or above at engine outlet, while the coolant temperature permissible for 30 minute operation is 90 degrees or above.

Item 31 -Fuel and lubricating oil used in operations must meet the Naval Stores Fuel Standards.

Item 32 - The following will be weighed and recorded separately.

Item 33 - The moments of inertia at dry weight about the three axes, with the center of gravity of the engine as origin, will be computed and recorded, in units of kilograms, centimeters, and seconds.


Chapter III - Structural Tests

Item 34 - Structural tests based on the various charts, documents and on the actual engine which the manufacturer submits under the stipulations of Item 15 will be made concerning the following points:


Chapter IV - Operational tests

Item 35 - Under operational tests, assessment of the performance, reliability and endurance of the engine will be made.

Item 36 - Operational tests are divided as follows:

Item 37 - Under engine performance tests, assessment will be made of the items mentioned in the following paragraphs. The details will be determined by the OinC:

Item 38 - Engine performance test results, aside from the rate of fuel consumption, will be corrected to standard atmospheric conditions, and recorded in graphic form.

Item 39 - All engine operational tests other than performance tests will be conducted at actual horsepower with shaft horsepower at standard atmospheric conditions as the standard.

Item 40 - The practice will be to take readings for engine operational tests, other than during take-off and similar special cases, after the throttle has been kept at a given setting for three minutes or longer.

Item 41 - 1st and 2nd operational tests will be conducted with the full complement of accessories and with a propeller or brake which has an equivalent braking power.

Item 42 - The 1st Operational test will comprise the following essential tests:


Item 43 - The 2nd operational test will be composed of the following essential tests:

Item 44 - The 2nd operational test will be conducted on the same engine which has undergone the 1st operational test.

Item 45 - OinC may on occasion order a practical operational test to be conducted on a different engine of the same model instead of an engine which has qualified in both structural and operational tests.

Item 46 - If engine failure occurs during tests, the parts concerned may be replaced by direction from the OinC, Naval Air Headquarters, depending on the circumstances. In such cases, part or all of the tests completed become void.

Item 47 - When repeating tests which have been invalidated by reasons given in preceding item, part of the tests may be omitted by permission of the OinC, Naval Air Headquarters, according to the circumstances.

Item 48 - Adjustments and repairs permissible in cases of engine failure during endurance operation will be limited to the following:



Precautions in Filling Out Table of Specifications

A. The following items are recorded in the column headed Carburetor or Injection Pump.

B. In the blank lines following the column for lubricating oil pump, the coolant pump, fan, and other such special accessories are to be recorded.

C. Various accessories are to be recorded in the blank columns following the columns for the propeller governor.