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The Lycoming XR-7755
Appendices
by Kimble D. McCutcheon
Abbreviations
ADM – Navy Admiral Rank
AEHS – The Aircraft Engine Historical Society, Inc.
AMC – Air Materiel Command
AKA – also known as
ATSC – Army Air Forces Air Technical Service Command (formerly Materiel Comman
bmep – Brake Mean Effective Pressure
bsfc – Brake Specific Fuel Consumption
bsoc – Brake Specific Oil Consumption
BuAer – U.S. Navy Bureau of Aeronautics
CDR – Navy Commander Rank
csfc – Cruise Specific Fuel Consumption
DPC – Defense Production Corporation, a wartime organization intended to expedite materiel production.
EO – Expenditure Order - an Air Corps numbering system used for budgeting and cost accounting
fmep – Friction Mean Effective Pressure
EPF – Expediting Production Funds, moneys earmarked for expediting materiel production.
CG – Center of Gravity
GE – General Electric
GFE – Government Furninshed Equipment
INA – Inspector of Naval Aircraft
IOM – Inter-Office Memorandum
hp – horsepower
imep – Indicated Mean Effective Pressure
inHg – inches of mercury, usually relative to another pressure, such as atmospheric pressure.
inHgA – inches of mercury absolute. A pressure relative to an absolute vacuum.
LCDR – Navy Lieutenant Commander Rank
MatCmd – Materiel Command, Materiel Division, etc.
mep – Mean Effective Pressure
NARA – National Archives and Records Administration
P&WA – Pratt & Whitney Aircraft, a Division of United Aircraft Corporation
PN – Part Number in reference to engine components
PPL – MatCmd Power Plant Laboratory
psi – pounds per square inch, a pressure measurement relative to another pressure
psia – pounds per square inch absolute, a pressure measurement above an absolute vacuum.
RADM – Navy Rear Admiral Rank
RCS – Resource Control Section, Wright Field
RD – A USNARA document subdivision peculiar to Record Group 342
RG – USNARA Record Group
rpm – revolutions per minute
sfc – Specific Fuel Consumption
TEL – tetraethyl lead
telcon – Telephone conversation/conference
USAAC – United States Army Air Coprs
USNARA – United States National Archives and Records Administration
Glossary
Boost – A manifold pressure increase over a given pressure, usually atmospheric.
Brake Mean Effective Pressure – mean effective pressure calculated from engine torque and rpm.
Endurance Run - An engine test run where the engine is run at a constant power setting for a specified period.
Farnboro Indicator – An instrument that plotted cylinder pressure as a function of crankshaft angle. Originally developed by the British Royal Aircraft Establishment at South Farnborough, Hampshire, the technology was licensed to Dobbie McInnes & Clyde Ltd of Glasgow, which built and sold the “Farnboro Indicators.”
Friction Mean Effective Pressure – The difference between indicated mean effective pressure and brake mean effective pressure. Composed of power required to drive accessories and the supercharger compressor(s), plus mechanical friction.
Grade – Fuel octane/performance number rating; oil viscosity.
Indicated Mean Effective Pressure – The theoretical mean effective pressure based on an engine’s indicator diagram.
Indicator Diagram – A Farnboro Indicator plot showing the relationship between cylinder pressure and volume. Since volume was a function of crankshaft angle, this metric often replaces actual cylinder volume.
Manifold Pressure – Induction system pressure, usually measured near a cylinder intake port in inHgA.
Mean Effective Pressure – working pressure in a cylinder averaged over the complete engine cycle.
Mixture Control Run – An engine test run where the power output is held constant at some predetermined value and the fuel/air ratio changed to achieve a desired objective, typically best power or best economy.
Octane Rating- A standard rating describing a fuel’s resistance to destructive self-ignition (detonation) when burning during the power stroke. Fuels with octane ratings of 100 have the same resistance to detonation as 2,2,4-Trimethylpentane (iso-octane).
Plancor.– a contraction of Defense Plant Corporation, a designation used by the government's Reconstruction Finance Corporation to administer and monitor the plants built to support the WWII effort. Across the nation, there were as many as 2,511 Defense Plant Corporation "Plancor" facilities, designated as Plancor 1 through 2511. There were 185 facilities built to directly support U. S. Army activities, designated as Army Plant 1 through 185, along with 56 facilities built to directly support U. S. Navy activities, designated as Navy Plants 1 through 56.
PN – Performance Number. Since the Octane Rating only goes to 100, the PN scale is for fuels with higher detonation resistance than iso-octane.
Veeder - A Connecticut-based manufacturer of counting equipment.
Run-in – A period of engine time run at low power that allows moving part to accommodate one another’s manufacturing imperfections.
stresscoat – Stresscoat testing involved the application of a brittle lacquer to the surface of a part to provide a visual indication of the distribution, direction, location, sequence and magnitude of tensile strains. The brittle coating fractured in response to the surface strain in the material to which the lacquer had been applied.
Timing Advance – The angle crankshaft angle between spark plug firing and when the piston reaches top center.
WPD – War Production Board, Washington, D.C.
Personnel
Ahern – MatCmd Power Plant Laboratory civilian employee
Blackwood, J. Glen – MatCmd Power Plant Laboratory civilian employee
Botta, Rico (CDR) – BuAer Power Plant Design Section Head
Brett, George Howard (Brig Gen, Maj Gen) – Chief of the Air Corps
Buchtel – MatCmd Power Plant Laboratory civilian employee
Carpenter, J. – Lycoming representative
Carroll, F.O. (Maj) – Experimental Engineering Chief
Chenoweth, Opie – MatCmd Power Plant Laboratory civilian employee
Columbo – MatCmd civilian employee
Cooper, W.K. – Lycoming General Sales Manager
Crowlitz – MatCmd ?
Dembach, A Lt – MatCmd Propeller Laboratory
Dunham – MatCmd Propeller Laboratory civilian employee
Echols, Oliver P. (Lt Col, Col, Maj, Gen, Maj Gen) – MatCmd Engineering Section Chief
Garlent, P.G. – Lycoming representative
Gillespie, J.M. (Col) – Chief, Power Plant Laboratory
Hoffman, Samuel Kurtz – Lycoming Chief Engineer
Johnson, E.A. – Lycoming representative
Keirn, Donald J. (Col) Acting Chief, Power Plant Laboratory, Propulsion and Accessories Subdivision
McKay, Don – Lycoming?
Minty, R.J. (Col) – Chief, Power Plant Laboratory
Newman – MatCmd Power Plant Laboratory civilian employee
Pace, E.M., Jr. (CDR) – Navy Bureau of Aeronautics Chief
Page, Edwin R. (Capt, Maj, Lt Col, Col) – MatCmd Power Plant Laboratory Chief
Patch, Maj – AAF Resodemt Representative at Lycoming
Perkins – War Production Board representative
Pinto – Air Force Resident Inspector at Lycoming
Posthauer, R.E. – Lycoming Manager, Military Contracts
Prescott, Ford L. – MatCmd Power Plant Laboratory civilian employee; Chief, Engine Research Unit
Spaulding, E. – Jack & Heinz representative
Wiegman, Clarence H. – Lycoming VP Engineering, Chief Engineer
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