John Meredith's M-46

John Meredith of Livermore, CA is another Sportsman Pilot alumnus who is making a second appearance in the magazine. In our Fall 1986 issue, we featured John and his Little Toot biplane, N91J, in an article based on an interview that took place that spring at the Merced, CA fly-in. This year at Merced... in virtually the same parking spot... we met John again, this time with a sleek, all-metal monoplane instead of a tube and fabric biplane.

For more recent subscribers to Sportsman Pilot, John Meredith is a native of Canada with degrees in both aeronautical and mechanical engineering who worked for Piper Aircraft at Lock Haven for a year, and Cessna at Wichita for seven and a half years before moving to California to get into the more lucrative field of scientific research. He learned to fly in the mid-1960s in an Aeronca Champ, and by choice has always remained a sportsman pilot and homebuilder. He has owned a Cessna 140 and his Continental O-200 powered Little Toot for decades, and has now added a third sportplane to his stable, the aircraft you see pictured here.

Looks like an RV-6, doesn't it? Actually, it began with an RV-4 tail kit, but from that point onward, John struck out on his own. When he built his Little Toot in the early 1970s, John drew upon his aeronautical engineering background to significantly modify the airframe, primarily to reduce weight without compromising its structural integrity. The Little Toot was grossly overbuilt, so John was able to engineer out about 120 pounds and still have a perfectly safe airframe. In the case of the RV-4 he started in 1982, his goals were to switch from tandem to side-by-side seating, both for a more congenial seating arrangement and to provide significantly more baggage space, and to increase efficiency by designing a completely new, albeit more complex, wing. Ultimately, all that has remained that is pure RV is the 1982 empennage, a few parts and components, and the latest pressure recovery wheel pants from Van's Aircraft.

To build his side-by-side fuselage, John looked at the structure of several all-metal homebuilts, the RV-3 and RV-4, the T-18 and others, and adopted the ideas he liked best. The fuselage width was limited to 39 inches by the T-18 canopy he planned to use, but he compensated by providing a generous amount of leg and head room. He used Cessna 150 seats, but mounted them on longer rails to allow a wider range of fore and aft adjustment.

John built his own mount for the 150 h.p. Lycoming O-320 he had purchased for use in the airplane, and built his own fiberglass cowling. A lot of thought and work went into reducing cooling drag, and, again, John borrowed heavily from existing, successful design. His cowling, for example, has features from a Twin Comanche nacelle: the bulkhead immediately behind the propeller, and the size of the cowl flap and air outlet. The rest flows into his fuselage contours quite nicely.

The engine itself is a stock carbureted O-320. The exhaust system is a commercially available crossover unit with mufflers, and required only a small change of angle in the tailpipe to fit inside his cowling. A four inch RV-4 prop extension was used, to which was bolted the same Sensenich wood prop that is commonly used on 150 h.p. RV-6s today.

The main gear consists of the same Wittman-type tapered rod unit Harmon Lang manufactures for RVs. The 5:00 x 5 Cleveland wheels and brakes were liberated from a Piper Tomahawk, but have not proven to be a good match for John's airplane. The swivel tailwheel assembly is an off-the-shelf item used on a variety of homebuilts today, and is completely satisfactory, John says.

The airplane's constant chord wing is the biggest departure from standard RV practice. It has a 49 inch chord rather than the 58 inch chord of RV wings, and its total area is 108 square feet, compared to the RV-4/6's 110 square feet. A NACA 23015 airfoil section is used, rather than the RV's slightly thinner 23012. The I-beam main spar has multi-layer caps, with the riveted layers dropping off as they progress outboard. The "semi-Fowler" flaps, as John calls them, and narrow chord Frise ailerons take up all the wings' trailing edges. Both inboard and tip fuel tanks are built into each wing, providing a total capacity of 45 gallons. Each 5.5 gallon tip tank has its own electric fuel pump to transfer gasoline to its corresponding 17 gallon main tank. The mains supply the engine via a conventional left/right/both valve, a boost pump, and engine-driven pump system. The rather complex wings, with all their systems, weigh 105 pounds each, and were harder and more time consuming to build than the four wing panels of his Little Toot, John recalls.

When the basic airframe was completed, John lined the cabin with sound deadening material, and installed upholstered sidewalls over it. Painting of the basically white airframe in DuPont Centauri acrylic enamel was entrusted to a friend who is a professional automobile painter. John painted on the two-tone blue and gray trim himself.

When finally completed in 1997, the airplane was found to have an empty weight, minus oil, of 993 pounds. Like almost all builders, John had hoped for somewhat less, but is happy with the airplane nonetheless. He was not happy after the first flight, however. Experiencing severe aileron snatch, he would spend the next nine months trying to come up with an engineering solution. Initially, he thought the sharp lower leading edges of his ailerons were causing the snatch when they extended out into the airstream, so he moved the hinge point back a half inch. That helped, but did not solve the problem. His next move was to open up the ailerons and install eliptical-shaped leading edges, which, again, helped some, but did not eliminate the snatch. The final solution proved to be the simple installation of some weather stripping material between the leading edges of the ailerons and the aileron spar.

In its present configuration, with the aileron modifications, the airplane cruises at 170 mph, burning nine to nine and a half gallons per hour. With only John aboard, the initial rate of climb near sea level is 1,600 fpm. With a passenger, the rate drops to just over 1,000 fpm. Top speed with just 150 h.p. and a fixed wood propeller compares quite favorably with a friend's RV-6 with a 180 h.p. Lycoming and a constant speed propeller, John says, so he feels his efforts to design an efficient airplane have proven successful.

He's not certain, however, that he would have undertaken the project had he foreseen it would take him some 15 years to complete. His Little Toot, by comparison, took just seven and a half years. Obviously, he could have saved a lot of time by simply building a 180 h.p. RV-6 when it became available as a kit, but that misses an all-important point. Although he is employed in another field today, John's first technological love has always been personal airplane design. Modifying his Little Toot and designing a new airframe ahead of his RV-4 tail were great sources of personal satisfaction- which is all the justification any aircraft building or restoration project needs. He is very happy with the handling and performance of his M-46, with all the favorable comments it receives wherever he lands, and, most of all, with the feeling of accomplishment he experiences every time he opens his hangar door and beholds his handiwork. That's about as good as it gets in our marvelous little world of sport aviation.