What a world. I had just landed the Dornier Seastar flying boat in the Gulf of Mexico a few miles off the Florida coast. We shut down the engines and were sitting on top of the Seastar cabin enjoying the view and wishing for a fishing pole when Dornier Seaplane Co. CEO Joe Walker called the chairman, Conrado Dornier, on his cell phone.
Conrado was somewhere in Europe when he answered his phone, and his first comment to me about the Seastar was "That is one terrific boat you have under you." That struck me, as an airplane guy, as the most revealing aspect of the Seastar. It is a good boat that flies, not an airplane that has been adapted to the water. And that makes all the difference in the world when you are miles from shore.
Conrado knows a thing or two about flying boats because the company that bore his family name has been building them for nearly 100 years. Before World War II, Dornier Aircraft built huge flying boats capable of crossing oceans nonstop. In all, it is believed at least 1,000 seaplanes have borne the Dornier name.
The flying boat business ended for Dornier — and soon for everybody else — after the war, but the knowledge and heritage of seaplanes stayed in the family. When fiberglass became a viable material for building boats, and flying boats, Dornier realized what this material could do to make seaplanes practical, and the Seastar concept was born.
The bane of floatplanes and flying boats is corrosion and leaks. Seawater relentlessly attacks the metals used to make conventional airplanes. Even with maximum maintenance and regular freshwater baths, an airplane operated on salt water must undergo a total overhaul with many parts replaced every two or three years. And the pounding involved in water operations will open the tightest riveted metal seams, creating leaks, so the floats and hull will need constant pumping to stay somewhat dry.
Fiberglass, in contrast, is corrosion-proof. And seamless construction of a fiberglass hull keeps water out of the bilge.
Dornier began development of the fiberglass Seastar in the early 1980s and by 1991 had FAA, as well as German, certification. Ownership of the Dornier Aircraft Co. passed from the family not long after, but the Seastar project was not sold with the other assets. The flying boat project was put on hold. Just more than a year ago, Conrado Dornier contacted Joe Walker, who has headed up sales for Gulfstream and Citation, to see if there was a market for the Seastar. Joe quickly found that the answer is yes.
In addition to a long track record of success selling airplanes, Walker had also done a stint with airplane startup manufacturer Adam Aircraft, where he learned a great deal about the challenges of building composite airplanes. He has a unique background for the Seastar program.
There are about 500 turbine-powered floatplanes in service around the world and about 4,000 piston airplanes operating on floats. Clearly, there is a requirement for airplanes that can operate from water, but floatplanes are a compromise. Each was designed to fly from runways and was later adapted to floats, so the original design tradeoffs were made in favor of runway operations.
The Seastar, on the other hand, was designed as a flying boat. While a floatplane has a very high vertical center of gravity, the Seastar's is low. All fuel in the Seastar is carried in the sponsons instead of the wings as in other airplanes, so the fuel weight is low. The Pratt & Whitney PT6 turboprop engines push and pull from their location in a single pod mounted on the center of the wing. That keeps engine weight central to reduce rolling moments. The central engines are also protected from virtually all water spray by the hull. Unlike on floatplanes, where the props spin in a steady stream of spray, there was no erosion on the Seastar propellers. I could run my fingers over the leading edge of the blades without fear of a gash, something not recommended on a floatplane propeller.
The sponsons also add to stability on the water and to a quick jump up onto the step for takeoff or taxi. The inboard sections of the sponsons are submerged when the Seastar is on the water, and their shape adds a great deal of lift as the hull accelerates. There is a step on each sponson to break the water surface tension. The sponsons also provide space for the main landing gear, so the retraction mechanism is simple compared with other flying boats that rotate the gear up to snuggle into the hull.
