This document summarizes recent (October-December 1924) research and development activities relevant to the Air Service. Article listing: Aircraft development: Airplanes: Observation airplane competition (Liberty engine); New records by Barling and Curtiss bombers; Douglas O-2 to supersede DH-4B; Curtiss XNBS-4 on acceptance test; XLB-1 test fuselage received; New pursuit design based on Boeing PW-9; Changes in Curtiss pursuit; Standardization of detachable propeller blades; Elias XNBS-3 below performance requirement; Skis for winter flying; Airships and balloons: Improvements to Terry mooring masts; RS-1 airship completed; Construction on TE-1 airship started; Armament: New beams for NBS-1 bomb racks; The oscillograph; Gun improvements on MB-3A airplanes; Equipment: Night illumination for A. S. flying fields; New night-flying equipment for airplanes; Ground temperature compensated altimeter; Mayall airplane engine heater; Handbook on new direct-driven generators; New parachute designs--Maintenance transferred to F.A.I.D.; Supercharger gauge; Photographic trucks; New camera for high altitude photography; Universal camera mount; Power plants: Division builds an air-cooled Liberty; Allison four-engine transmission; First Curtiss R-1454 radial accepted; Research and experiment: Resume of Engineering Division serial reports: Airplane section: Resume of development of Gallaudet DB-a--Serial no. 2369; General procedure in airplane design--Serial no. 2405; Resistances of streamline fuselages of racing airplanes--Serial no. 2406; Aerodynamical characteristics of TP-1 and CO-2 fuselages with and without chassis--Serial no. 2413; Collection of unrelated model airfoil tests--Serial no. 2416; High speed test of wing section with bullet holes in fabric--Serial no. 2419; Application of 'Method of least work' to redundant structures--Serial no. 2420; Determination of engine power at altitude from propeller characteristics--Serial no. 2422; Resistance of center section type radiator--Serial no. 2421; Wing analysis of Lepere (USA-C-11) airplane--Serial no. 2425; The power plant problem in heavy bombardment airplanes--Serial no. 2427; Static tests conducted at the Division; Wind tunnel tests in McCook Field five-foot tunnel; Material section: Babbitting direct to steel--Serial no. 2351; Mechanical properties of magnesium-zinc-aluminum alloy castings--Serial no. 2353; Column strength of duralumin tubing with fixed ends--Serial no. 2376; Applications of load in testing fabrics--Serial no. 2411; Laboratory tests made sole basis for accepting spar varnish--Serial no. 2415; Power plant section: Salt-cooled valves and hardened guides for aircraft engines--Serial no. 2328; Power plant laboratory standard test methods and computations--Serial no. 2343; Description and test of Morehouse blower engine (First design)--Serial no. 2350; Crank pin bearing pressures on Liberty 1-inch connecting rod bearing--Serial no. 2377; Test of Rockwell slotted head Liberty valves--Serial no. 2378; The mercury-vapor turbine as an aircraft power plant--Serial no. 2379; Behavior of three standard A.S. spark plugs in high compression Liberty engine--Serial no. 2390; Performance curves and sectional views of aircraft engines--Serial no. 2407; 50-hour reliability tests of two Rock Island Arsenal 'Liberties'--Serial no. 2389; Endurance tests of Curtiss D-12 engines; Technical data section: Competing airplanes in air races (1924)--Serial no. 2417; Investigation of materials: Paste colors for insignia; 'Krachow' and 'Ta Sua' wood from Siam; Cadmium and chromium plating; Effect of gauge width on elongation--Standard test-piece; World's largest airplane wheel and tire, size 64x14; New books and documents--Reference data on aeronautical development and engineering in the United States and other countries added to the technical files of the Air Service, Engineering Division--International activities: Great Britain; Japan; United States; Competitions, records, etc; Aerial navigation: Airways; Meteorology; Regulation; Instruction: Air Service Engineering School; Research: Aerodynamics; Design and computation; Aerofoils; Aircraft--Heavier-than-air: [General]; Atlantic; Consolidated; Curtiss; DeHaviland; Engineering Division; Fokker; Gourdou-Leseurre; L.-W.-F.; Navy PN-9; Nieuport; Rukh; Wren; Aircraft--Lighter-than-air; Equipment; Fuels; Gases; Materials: Fabric; Metals; Paper; Rubber; Wood; Miscellaneous tests; Parachutes; Photography; Power plants: [General]; Lawrence; Liberty; Wright; Carburetors; Fuel systems; Ignition systems; Starters; Propellers; Water recovery apparatus.