Because concrete and other hard-surfaced runways make wartime airfields easily spotted from the air, the army is now using grass fields extensively. Keeping such fields in condition involves a lot of grass cutting, and this problem has been solved by a tractor-pulled gang mower, called a “grass blitzer,” that can trim a 500 acre field in a little more than 10 hours at 20 miles an hour. For transport, the complete mower can be loaded on a trailer which is towed by the same tractor that pulls the mower. In use, the cutting portion is suspended from the frame so it will clip evenly and prevent the appearance of telltale takeoff marks. Equipped with floodlights for night operation, the mower also carries a short-wave receiver so the field officer may signal the operator when airplanes take off or come in.