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Meet the MarsMeet the Mars

Giant Martin flying boat makes first AirVenture visitGiant Martin flying boat makes first AirVenture visit

The Martin Mars JRM-1 towers above visitors as they approach the giant seaplane in a motor launch. The four-engine seaplane—it has no landing gear—is 44 feet, 7 inches tall. It’s 120 feet, 3 inches long; and it has a wingspan of 200 feet—approximately that of a Boeing 747. Powered by four 2,500-horsepower Wright R3350 radial engines, the Mars has a maximum gross weight of 145,000 pounds. It draws about 5.5 feet of water.

Only six were built for the U.S. Navy, late in World War II; they were retired in 1958. In the early 1960s, the remaining four aircraft were purchased by a consortium of Canadian timber companies for conversion to water bombers, to fight fires in their coastal forests. One of the four crashed, and another was destroyed in a hurricane. Coulson Flying Tankers bought the last two in 2007. Named by manufacturer Martin, the Hawaii Mars has been updated with a glass cockpit, and made its first-ever visit to EAA AirVenture this week. The Philippine Mars is maintained in an almost-airworthy condition by Coulson at its base in Port Alberni, British Columbia.

“This is the last flying Mars in the world and the largest warbird ever built,” said Wayne Coulson, chief executive officer of Coulson Flying Tankers. “There isn’t a better aviators’ venue than EAA AirVenture, so it’s an honor to be part of this world-class event. We’re very excited to bring the Hawaii Mars to Oshkosh as we look for new opportunities and host potential clients, as well as showcase this magnificent airplane’s capabilities.”

Today the historic aircraft have no firefighting work, and while Coulson would like to see them go to museums, both are considered to be for sale.

Coulson Aviation's Martin Mars water tanker is moored at Lake Winnebago. Photo by David Tulis.

Because the Martin Mars is a true flying boat, it has no landing gear and cannot land at Wittman Regional Airport. Instead, it is moored near the EAA Seaplane Base on Lake Winnebago, a few miles southeast of the main fly-in grounds. Coulson Flying Tankers is selling tours of the giant aircraft, and it has flown in two airshows already this week. It is scheduled to fly again Friday afternoon and Saturday evening. The Mars crew plans to depart Monday for their return to Canada.

In addition, the company is offering pilots the opportunity to fly the historic aircraft. “The Martin Mars aircraft are truly amazing pieces of World War II history. These aircraft hold numerous world records during this era, and before they are retired, we are offering aviation enthusiasts a chance to fly this incredible piece of aviation history,” Coulson said.

The central section of a Martin Mars is large, and spans two decks. Photo by Mike Collins.

Coulson’s company has been training Chinese test pilots in Canada, helping prepare them to fly the new TA-600 amphibious aircraft now being built in China by the Aviation Industry Corp. of China. The pilots from China are training in Coulson’s Hawaii Mars aircraft, taxiing and flying the large flying boat in preparation for flying the new Chinese design, which will have a 3,000-gallon water capacity and is powered by four turboprop engines.

As water bombers—the Mars’ No. 3 and No. 4 fuel tanks were converted to carry water scooped from a lake—they can carry 7,200 gallons of water. It’s scooped at a rate of one ton per second, and the airplane takes 30 seconds to load, explained Charlie Watts, who works for Coulson as a flight engineer on its C-130 tankers. “You can feel it when the probes go down” to scoop water, because the Mars pitches forward, he said. Foam or gel fire suppressants can be injected into the water as it is loaded, depending on what is needed for the fire.

These massive, color-coded push rods control movement of the elevator (red) and rudder (yellow) of the only Martin Mars currently flying. Photo by Mike Collins.

A tour of the aircraft reveals its nautical heritage. To most pilots, the structure resembles a boat more than an airplane. Hatches and their mechanisms are very nautical in appearance, as are the stairways between decks. The rudder and elevator are controlled by massive push rods extending from the cockpit, and those controls are locked using pins from inside the seaplane’s hull. Ingeniously, those pins are used as keys to interlock those control surfaces to the flight controls—preventing takeoff when the controls are locked.

Many Coulson employees have been surprised by the interest shown in the Hawaii Mars at AirVenture—the giant seaplane’s first-ever airshow. “The interest is almost surprising, but it really shouldn’t be,” said Dev Salkeld, a flight engineer on the Mars. “You come to a place like this and there are a lot of aviation enthusiasts.”

This schematic of a Martin Mars fuel system is part of the flight engineer's station. Photo by Mike Collins.

The aircraft flew nonstop from Port Alberni to Oshkosh. The trip took nine hours, including a diversion around some weather. It burns about 420 gph in cruise flight, but that increases to 780 gph at maximum power—often the case during firefighting missions.

The Mars is moored to a 12,000-pound anchor in Lake Winnebago; for fueling, it’s moved to another buoy closer to shore, and a hose is floated out to the aircraft. Fuel is then pumped from a tanker truck on the shore. “It takes a while to fuel,” one crewman said. “We usually use our own truck, and it has a faster pump.”

  • Coulson Aviation's Martin Mars seaplane flies in the EAA AirVenture 2016 airshow. Photo by Mike Collins.
  • Coulson Aviation's Martin Mars demonstrates its firefighting capability as it drops 7,200 gallons of water on Wittman Regional Airport during AirVenture 2016. Photo by Mike Collins.
  • The flight engineer's station in Coulson Aviation's Martin Mars seaplane actually requires two flight engineers. Photo by Mike Collins.
  • Here's a study in contrast: Modern Bose active noise cancelling headsets hanging from the flight engineer's station of a World War II-era Martin Mars seaplane. Photo by Mike Collins.
  • Coulson Aviation's Martin Mars water tanker splashes in for a landing at Lake Winnebago. Photo by Mark Evans.
  • The throttle quadrant of a Martin Mars seaplane offers only four throttles. The aircraft's two flight engineers handle the other engine adjustments. Photo by Mike Collins.
  • Coulson Aviation's Martin Mars water tanker approaches for a landing at Lake Winnebago. Photo by Mark Evans.
  • A work platform, hung beneath the Martin Mars' number four engine, allows the crew to perform maintenance while the seaplane is moored at the AirVenture seaplane base. Photo by Mike Collins.
  • The Martin Mars towers above visitors as they approach the seaplane at EAA's seaplane base during AirVenture 2016. Photo by Mike Collins.
  • If you were in the cockpit of the only flying Martin Mars, wouldn't you take a selfie? Of course you would. Photo by Mike Collins.
  • Clouds part behind the Martin Mars water tanker moored at Lake Winnebago. Photo by Mark Evans.
  • Coulson Aviation offered tours of its Martin Mars during EAA AirVenture 2016. Here, a visitor photographs the cockpit. Photo by Mike Collins.
  • These ducks seem eager to investigate the Martin Mars, moored at the EAA seaplane base during AirVenture 2016. Photo by Mike Collins.
  • Coulson Aviation's Martin Mars water tanker arrives over trees for a landing at Lake Winnebago. Photo by Mark Evans.
  • Michaela Brown looks at Coulson Aviation's Martin Mars water tanker from her perch atop a Grumman Albatross at Lake Winnebago during EAA AirVenture 2016. Photo by David Tulis.
Mike Collins

Mike Collins

Technical Editor
Mike Collins has worked for AOPA’s media network since 1994. He holds a private pilot certificate with an instrument rating.
Topics: EAA AirVenture, Aircraft

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