Skiplanes & Seaplanes | Martin JRM Mars Dropping Water The Martin JRM Mars flying boats are the world’s largest flying boats ever flown operationally. Although seven were built, only two remain flying, the Hawaii Mars JRM-3 pictured here and the Philippine Mars. They have been refitted as firefighting water bombers carrying 7,200 gallons of water. This Martin JRM Mars is dropping 7,200 gallons of water on runway 18/36 at AirVenture. You might ask: how do they get the water? Well, the Captain lands on the water normally, but keeps the the aircraft “on the step” at 60-70 knots. The Flight Engineer controls the power to keep the aircraft “on the step” and selects the scoops to the “down” position to inject the water into the tanks at the rate of about a ton per second. The 7200 gallon pickup time averages 25 seconds. When the tanks are full, the scoops are raised, takeoff power is applied by the Flight Engineer and the Captain makes a normal loaded takeoff. Pretty slick! For more flying information, see Remembering Oshkosh | a 7 Image Story.
