This document summarizes recent (Third quarter 1925) research and development activities relevant to the Air Service. Article listing: Aircraft development on Engineering Division program: Airplanes: Loening Amphibian COA-1 (production model); Cox-Klemin ambulance airplane, Model XA-1; Performance tests on Curtiss P-1; Performance of Douglas transport with different propellers; Performance increase with geared engine and large propeller (L-W-F transport); Huff-Daland advanced training airplane ('Dog Ship'); Bids asked on heavy bombardment monoplane; Complete XHB-1 heavy bomber to be built; D-12 engines for Curtiss O-1s; Design studies; Disposition of the World Cruisers; Metal wings (Thomas-Morse design); Woven plywood wing (Forest Products Laboratory); Crop census by airplane; Collecting rust spores in the upper atmosphere; Airships and balloons: All-metal car for TE-1 airship; RS-1 airship; Balloon development; Armament: Aircraft bomb truck, Type A-1; Nelson synchronizer adapted to late model engines; Tests on wing tip flares; Wind detection signals; Machine guns to be mounted inside wing; New machine gun synchronizer, Type E-4; Equipment: Aerial photographs transmitted over telephone wires; Transmitting tests on radio set SCR-134; Ground lighting equipment; Landing light mounting on DH-4B standardized; Airship instruments; Experimental engine starters; Ignition shielding for Liberty engine; Power plants: Curtiss R-1454 engine with Type 'M' cylinders; Development of Almen 'Barrel' engine; Tests on Packard engines; Shrunk-on propeller hub flange; Jump-gap distributor heads; Combination generator and magneto mounting flange; Investigation of bearing loads; Research and experiment--Resume of Engineering Division serial reports: Airplane section: Longitudinal stability of airplanes--Serial no. 2531; Correlation of flight test and wind tunnel data--Serial no. 2570; Comparative tests on experimental metal ribs and spars--Serial no. 2575; Test of valves for RS-a airship--Serial no. 2583; Static tests conducted at the Engineering Division; Wind tunnel tests; Armament section: Test of Fokker synchronizer--Serial no. 2492; Instructions for mounting Type III airways flares--Serial no. 2493; Racks for mounting Type III airways flares--Serial no. 2533; Test of Carmier gun sight--Serial no. 2586; Equipment section: Ignition interference in airplane radio reception--Serial no. 2451; Altimeter calibration standard--Serial no. 2468; Barometric altimetry and altimeter calibration standards--Serial no. 2440; Preliminary report of crash tests--Serial no. 2522; Location of vent opening in fuel tank; Installation of LeNivex hydrostatic fuel level gauge--Serial no. 2535; Service radio equipment--Serial no. 2543; Navigation methods--Serial no. 2559; Tests on Purox liquid oxygen storage and shipping container--Serial no. 2572; Practical field service use of oxygen--Serial no. 2478; Performance of airspeed tubes in rain and freezing rain--Serial no. 2585; French leakproof tank (S.E.M.A.P.E.)--Serial no. 2579; Material section: Dopes and their application--Serial no. 2550; Flying section: Performance tests; Clogging of fuel strainers--Serial no. 2567; Power plant section: Test of Honeywell automatic shutter control--Serial no. 2499; Piston side thrust in Model R-1 radial engine--Serial no. 2504; Bearing loads and stress analysis of Model X-4520 engine--Serial no. 2508; Development of slipper type piston for Packard 1A-1500 engine--Serial no. 2517; Cooling test of 'Zero-Foe' radiator anti-freeze--Serial no. 2519; Standard test of Curtiss D-12 low and high compression engines--Serial no. 2528; Investigation of materials: Army-Navy conference on standards and specifications; One type of dope for all airfoil surfaces; Tru-Lay cable; New books and documents--Addition to Engineering Division technical files during third quarter, 1925--International aeronautics: [General]; Great Britain; Italy; Japan; Siam; United States; Competitions, records, etc.; Aerial navigation: Airways and airdromes; Meteorology; Instruction: Flying School, Kelly Field; Tactical School, Langley Field; Research: Aerodynamics; Forces and moments; Stress computations and design; Structural analysis, and design; Aircraft--Heavier-than-air: [General]; Aero; Atlantic; Breguet; Caproni; Curtiss; C.T.; Douglas; Entler; Farman; Hanriot; Hansa; Macchi; N2M; TG4; UO-1; Aircraft--Lighter-than-air; Armament; Equipment; Instruments: [General]; Parachutes; Fuels and lubricants; Materials: [General]; Dopes, protective coatings, etc.; Textiles; Glue; Wood; Tests;Photography; Propellers; Power plants: [General]; Bristol; Curtiss; Farman; Kinney-Noble; Liberty; Mayback; Rolls-Royce; Siddeley; Wright; Fuel systems; Ignition devices; Radiators; Starters; Radio.