This document summarizes recent (Second quarter 1925) research and development activities relevant to the Air Service. Article listing: Aircraft development on Engineering Division program: Airplanes: Curtiss P-1; All-metal observation airplane, Model XO-6; Design competition for night observation airplane; Huff-Daland XLB-1; Design competition for heavy bombardment airplane; Heavy bombardment monoplane proposed; Douglas C-1 transport; New racers for 1925 Pulitzer; Brakes for airplanes; Airships and balloons: RS-1 airship; 200-foot mooring mast for Scott Field; New gas cylinder cleaning and painting machine; Armament: External bomb hoist, Type E-1; New type B-5 bomb shackle to replace Type B-4; Rack for 4,000-lb. bomb ready for service test; Pyralin beads for gun sights; Equipment: Visual indicator for radio beacon signals; Incandescent beacons and landing lights; Night aerial photography by flashlight; ‘Quick-work’ photography; New mount for T-1 and T-2 cameras; New view finder, Type A-2; Photographic equipment on DH4M-2P airplanes; Power plants: High speed engine development; Three air-cooled Liberty engines on order; To build 1200-h.p. air-cooled ‘X’ type engine; Research and experiment--Resume of Engineering Division serial reports: Airplane section: Analyzing and predicting airplane performance—Serial no. 2355; Stress analysis of Phillips’ ‘Alouette’ airplane—Serial no. 2470; Torsional test of Elias XNBS-3 fuselage—Serial no. 2481; Design of plywood webs for box beams—Serial no. 2500; Study of wing weights—Serial no. 2527; Effect of sweep back and sweep forward on an airfoil—Serial no. 2558; Airplane design; Static tests conducted at the Engineering Division; Wind tunnel tests; Equipment section: Test of oxygen regulator, Prouty type—Serial no. 2498; Test of Carter gasoline gauge--Serial no. 2512; Method of reducing flight test data to standard air--Serial no. 2521; Flying section: Performance tests; Material section: Spoke lacing on airplane wheels—Serial no. 2518; Clogging of fuel strainers--Serial no. 2567; Power plant section: Instructions for standard engine test and report--Serial no. 1506 revised; Test of ‘Boyce-ite’ fuel--Serial no. 2467; Performance of Packard 1A-1237 engine with modified intake manifolds and camshafts--Serial no. 2483; Performance of Stromberg NA-U6 carburetor on Wright ‘H’ engine--Serial no. 2486; Best location for maximum speed—Serial no. 2487; Endurance test of Liberty engine equipped with various experimental parts and materials—Serial no. 2490; Investigation of materials: Investigation of British doping scheme; Reliability of welds; Protective coatings for steel; Universal cup grease for aircraft; New books and documents—Data on aeronautical development in United States and foreign countries added to technical files of the Engineering Division, U.S. Army Air Service—Documentary data on international aeronautics: Great Britain; Germany; Italy; Japan; United States; Competitions, exhibitions, records, etc.; Aerial navigation; Instruction; Research: Aerodynamics; Airfoils, etc.; Structural analysis, and design; Aircraft--Heavier-than-air: [General]; Avia; Boeing; Breguet; C.N.T.; DeHaviland; Dewoitine; Dornier; Farman; Fokker; F4C; Huff-Daland; HN; Macchi; Potez; SC; Sikorsky; Vickers; Vought; Aircraft--Lighter-than-air; Armament; Equipment: Instruments; Parachutes; Seats; Transportation; Materials: [General]; Alloys; Corrosion and inhibition; Dopes, paint, etc.; Fabric; Anti-freeze compounds; Gas; Fuels and lubricants; Rubber; Wood; Tests and miscellaneous; Power plants: [General]; Breitfeld-Danek; Gnome; Hesselman; Tampier; Vaslin; Engine accessories; Superchargers; Photography; Propellers.