A Very Special Eipper GT400
By Dan Grunloh, Editor – Light Plane World, EAA 173888
Rick and his GT400 Special at Tommy’s Airpark, Edinburg, Illinois, in 2010
If you saw Rick Pierson’s Eipper GT400 Special at a fly-in somewhere, you might think it’s merely a very beautiful version of this well-known design. Calling it a “Special” is an understatement once you begin to explore the extensive changes and improvements in the airplane. He worked very hard to reduce drag and to save weight to the point of using thin washers and thin stop nuts wherever feasible. The resulting performance of the aircraft is indeed extra special.
Rick started out with a partially constructed Eipper GT400 kit in 2005 and began to immediately make changes and custom enhancements to the airframe. Thus began a two-year building effort that resulted in the one-of-a-kind airplane. He has been flying for 30 years, and his previous plane was a Rotax 582-powered two-place Quicksilver which he used to introduce others to the flight experience. Located in Evansville, Indiana, he utilized the services of Mark Smith of Tri-State Kite Sales in Mount Vernon, Indiana, who has been providing aftermarket and custom parts to Quicksilver enthusiasts for over 25 years. It should be said that few if any of the changes have been approved by the manufacturer, but all have been proven successful by previous clients of Mark and by the 400 hours logged thus far on Rick’s airplane since it was completed in 2007.
Starting at the front, Rick decided he didn’t like the nose wheel design that necessitated a large hole in the bottom of the pod to accommodate the springs and steering hardware. He installed a heavy-duty front fork and redesigned it so all the steering mechanism is inside the pod. All bell crank and steering bearings were replaced with precision bearings including in the yoke. Mark used the original pod from the kit as a donor to produce a mold for a new pod. The new design provides a much cleaner installation and incorporates a removable nose cone for maintenance and inspection of the nose wheel assembly and instrument panel. It features NACA scoops for a fresh air inlet system that terminates at the main fuselage bulkhead which was similarly molded after the original. The fiberglass seat was also redesigned for better comfort, and all three components came out lighter in weight than the originals. The custom pearl paint job with candy orange trim was done by a friend who paints show cars.
The original kit didn’t include a windshield, which gave him the opportunity to make it from scratch in the style of the Eipper GT500. The windshield support rail ends are hidden on the side of the panel. Custom removable side doors with fresh air vents were built to match the custom pod and custom windshield. The wing covers were taken apart and modified to allow for an increase in the number of ribs. New wing support struts were constructed to reduce the dihedral to 2 degrees. Custom heavy-duty landing gear legs were cut out of aluminum to fit the existing gear sockets in the fuselage. It’s equipped with Hegar hydraulic brakes with (of course) a custom brake lever in the cockpit. The custom GT500-style aft pylon cover extends upward to better close the gap on the underside of the wing and features long zippers and belly bracing for carrying cargo.
A side view of the GT400 Special shows that everything possible was covered in streamlined fairings. While the wing covers were open for the addition of the extra ribs, streamlined fabric openings were added to accommodate the aileron push-pull tubes. No cables were used in the aileron control system. Throughout the building process every effort was made to concentrate on weight savings and also drag reduction. If the manufacturer provided a bolt that required three washers, he replaced it with a shorter bolt using a single thin washer and used thin Nyloc stop nuts where feasible. When asked how you make an airplane lighter, he responds, “You just keep throwing money at it.”
A look up into the center section of the wing reveals he has removed the bulky (and heavy) manual wing flap mechanism and replaced it with a small electric motor. An electric flap indicator is built into the side panel. Rick believes the electric flaps didn’t add any weight to the airframe. The flaps have a 5-degree upward reflex that increases the cruising speed. Not visible is an 8-gallon main fuel tank inside the wing and the Facet fuel pump that transfers fuel from an additional 10-gallon tank mounted behind the seat. The fuel is filtered twice before it enters the engine. With a total capacity of 18 gallons and a cruise fuel consumption of 3.5 gallons/hour, he can fly for 4.5 hours and still have a 30-minute reserve. His longest flight so far was 3 hours and 20 minutes, and flying on long trips with friends with less range (which is everyone) has taught him respect for how much time is lost on fuel stops.
The tail shows some unique features and adaptations from the two-seat Eipper GT500. The all double surface tail has internal bracing similar to the GT500, and the unique fabric fairing into the main fuselage tube doubtless reduces the drag considerably at that junction. Rick told Mark he wanted the fabric tight enough he could bounce a coin off of it, and it took a lot of custom work to get that way. Mark also included adjustable mounting points for the vertical stabilizer that enabled Rick to adjust the rudder trim perfectly. The dorsal fin under the tail, also from the GT500, greatly improves the handling and stability when the side doors are installed.
Rick’s Special has almost every option you can think of and one more few of us would consider. He has a spare Rotax 503 engine with identical hookups he can swap in and out quickly. He doesn’t like to be grounded for any length of time, not even for a periodic decarboning and checkup. His first engine had a mysterious crankshaft failure at 50 hours that put him down in a field, so Mark provided a loaner engine while he looked for a replacement. Eventually he convinced Mark to sell him the engine even though he had found a replacement. The pictures here show the plane in its summer configuration. In winter, two 3-inch hoses are connected to a custom fiberglass heat box on the engine that provides ample cabin heat even at very low temperatures. The standard upper wing gap cover is replaced with a winter version that encloses the hoses for a more streamlined installation.
The performance of the completed airplane matches the appearance and easily exceeds the expectations of most observers. The 72-inch two-blade tapered tip Ivo prop yields an amazing 1,000 feet/minute climb rate and even more in winter. He can cruise at 75 mph (which is VNE for the airframe) while turning 5,500 rpm and burning 3.5 gallons of fuel/hour. The finished empty weight of 420 pounds is considered low for the number of options he has installed. Some owners of overweight GT400s with no fairings and with round struts will find these numbers to be almost unbelievable, until they fly alongside Rick and his plane.
Could you build a GT400 Special just like this one? I think probably not. The components that make it special aren’t routine aftermarket items pulled out of a parts bin. Many were the result of collaboration between Rick and Mark who pondered each solution while studying the problem in Mark’s shop. Most folks who know him would agree that while Mark could and has produced whole airplanes from scratch for the ultralight market, what he likes best is working on individual projects with friends and fellow Quicksilver enthusiasts to help them do something special. To contact the community of Quicksilver enthusiasts, try the Quicksilver Ultralight Owners Yahoo! group.