April 1, 2004
By Thomas A. Horne
The New Piper's Seminole began life 26 years ago as one of a new breed of multiengine trainers. Over the years, its competitors, Beechcraft's Duchess and American General's Cougar, have dropped by the wayside. Today the Seminole and the Beechcraft Baron reign as the world's only light twins in current production. The Seminole's total sales have topped the 683 mark; some 147 were sold in the past four years (with 2002's 60 deliveries holding the all-time annual sales record). Its closest competitor would be Diamond's diesel-powered DA42 TwinStar — a canopied, turbocharged, 270-horsepower (135 hp per side) airplane being built in Austria. The DA42 was unveiled with much ballyhoo in 2002, but has yet to be certified.
The Seminole was built with an eye toward safety. In the light twin's glory years of the 1950s and 1960s, flight instructors and designated examiners had little federal guidance on practical test standards. In attempts to provide real-life engine-out experiences, some instructors used poor judgment and went too far. Hair-raising drills such as engine cuts right after takeoff, stalls with a windmilling engine, and engine-out stalls in turns sometimes made engine-out practice all too real. Multiengine training accidents began to mount.
One reason why earlier multi-trainers tended to bite back has to do with their behavior near V MC. V MC — defined as the minimum airspeed at which directional control can be maintained with the critical engine inoperative — in pre-Seminole days meant uncommanded rolling and yawing at airspeeds well above the stall.
Students practicing their V MC demonstrations would put the left, or critical, engine (the one that, were its power lost, would create the most adverse handling characteristics) at a zero-thrust setting, advance the right engine to full power, then reduce airspeed by pitching up. At or near V MC — marked by a red radial line on the airspeed indicator — students would begin to notice the onset of an uncontrollable roll and yaw toward the "dead" engine, in spite of full opposite rudder. If not caught in time, or if the loss of control happened suddenly, or if the student botched the recovery by letting airspeed bleed off or leaving the good engine's power on, the result could be a roll to the inverted. Sometimes this ended with fatalities, especially in cases where instructors cut an engine right after takeoff and students allowed airspeed to drop to V MC — or lower.
By the late 1970s, Piper and Beechcraft decided to tame V MC by installing counterrotating propellers on their new multi-trainers. This eliminated the critical engine and lowered V MC. In the Seminole's case, V MC is 56 KIAS — just one knot above the 55-knot stall speed in the landing configuration and one knot below the clean stall speed.
Never mind that the Wright brothers used counterrotating propellers on their historic 1903 Flyer. Counterrotating propellers were billed as a newly discovered antidote to the V MC rollover, and they caught on. The reduced p-factor and lift moments from the right propeller — thanks to its "new" counterclockwise rotation design — meant less violent rolling and yawing at V MC, or any other asymmetric-power condition. Do a V MC demonstration below 4,000 feet msl or so in a Seminole, and you're much more likely to approach a conventional stall before any dangerous rolling sets in. Above 4,000 feet, the airplane may not be as polite. Stall speed is a constant, but V MC decreases with altitude because asymmetric thrust decreases with altitude. At some point, V MC falls below stall speed. Enter a stall with asymmetric power above that altitude, and you could be faced with a potentially nasty stall, one with a dangerous roll-yaw combination.
But the fact remains: Seminoles continues to be one of the tamest, friendliest light twins ever built. They're the unchallenged mainstays of many multiengine training fleets, both large and small, and they're flying all over the world. Major aviation schools top the list of big-volume customers. Some of the schools that use Seminoles as their flagships include: Embry-Riddle Aeronautical University (18 Seminoles); FlightSafety International (25); University of North Dakota (14); Pan Am Academy (17); Delta Connection Academy (seven); and the biggest operator — Airline Transport Professionals Inc. (ATP) — with a whopping 76 Seminoles. The overseas market is strong, too. I once ferried a Seminole all the way to Bangkok, Thailand, where it now serves in a military flying club.
The Seminole is designed with simplicity in mind. The fuselage and wings are virtual clones of Piper's Arrow single-engine retractable, which explains why some call the Seminole a "Twin Arrow." The flaps are mechanical, and are actuated by the same stone-simple floor-mounted hand lever used in scads of earlier Piper singles, as well as the new 6X and 6XT. Two 55-gallon fuel tanks (protected by firewalls) live in huge nacelles behind the engines, and there are only three fuel selector positions: On, Off, and Crossfeed.
The only quirky system is the Janitrol gasoline-fired heater, mounted in the nose cone. It can overheat without a vigorous flow of outside cooling air. After landing, you have to remember to shut off the heater and run its fan to keep it from overheating. There's a squat switch that is supposed to prevent an overheat, and an annunciator that warns of a too-hot Janitrol, but the idea of a gasoline heater out there in the nose by its lonesome sometimes makes me worry. On the other hand, it does put out the cabin heat.
Beginning with the 2000 model year, New Piper made some really nice improvements over the original design. The panel is clean and uncluttered, with a Garmin GNS 430 GPS/nav/com as standard equipment. A horizontal situation indicator (HSI) and second GNS 430 are part of the very popular optional avionics package, which lists for an extra $30,780.
The battery master, magneto, fuel pump, and external light switches have been moved from a pilot's sidewall panel to front-and-center locations on the instrument subpanel. Large dual-pointer manifold pressure and tachometer gauges now are stacked vertically, which puts them right in the pilot's — and instructor's — line of sight. Pre-2000 models had these stashed above the pilot's right knee. Newer models also have a nice annunciator panel, including that Janitrol overheat warning.
The propellers' unfeathering accumulators are other great standard features of newer Seminoles. These store oil pressure, then release it to the prop hub when you want to unfeather an engine. To do an airstart, all you do is advance the prop lever at the appropriate airspeed (100 to 120 knots) and the accumulators start the props turning. Sure beats the old design, which calls for using the starters to uncage the props.
My most recent Seminole time was in a trainer operated by ATP. ATP offers packaged courses aimed at earning advanced certificates and ratings, as well as ab initio training that takes you from ground-pounder to airline transport pilot.
ATP has its own operations manual, and flying the school's Seminoles means learning its procedures and checklists. Some, like limiting V LE and V LO to 120 knots (instead of the pilot's operating handbook's 140 knots), are meant to spare the airplane from unnecessary wear and tear. Others are to make you fly the airplane with a disciplined professionalism.
As an instrument flying platform, the Seminole is exemplary. Thanks to the T-tail there's little in the way of pitch changes and retrimming requirements with configuration changes. Use the proper target values and the airplane behaves well during instrument procedures.
Cruise speed? Single-engine climb performance? Range? These values are about what you'd expect from a light piston twin. The book says you can see speeds as high as 168 KTAS at 75-percent power, but in my experience this is often optimistic. Single-engine climb, posted as 212 fpm, is as lackluster as any light piston twin. But with temperatures below standard and a light load, you can see single-engine climb rates pushing 400 fpm. Single-engine work? In spite of the counterrotating engines there's more than enough asymmetric thrust to give students strong legs.
Landings are uncomplicated, and using short-field techniques (full flaps, 75 KIAS or slightly less over the fence, depending on weight) can produce breathtakingly carrierlike landing distances.
Although aimed at the training market, the Seminole also appeals to a cadre of owner-operators who simply want a late-model multi for peace of mind when flying at night, over mountains, or over water. I can understand that. One of the best flying adventures I ever had was in a Turbo Seminole, only 87 of which were built. I flew N8264F, a demonstrator loaded with options — even weather radar — on a huge loop around the Caribbean, stopping at Stella Maris, South Caicos, Great Inagua, St. Thomas, St. Croix, Antigua, Martinique, Jamaica, and the Cayman Islands. The trip proved that the Seminole is as fine and capable a cruising machine as it is a trainer.
That was way back in 1981, when the Seminole was still a fresh concept and there was debate about whether the design would hang in there for the long run.
Now we have the answer.
E-mail the author at [email protected].
For more information, contact The New Piper Aircraft Inc., 2926 Piper Drive, Vero Beach, Florida 32960; telephone 772/567-4361; fax 772/978-6584; or visit the Web site ( www.newpiper.com).
All specifications are based on manufacturer's calculations. All performance figures are based on standard day, standard atmosphere, sea level, gross weight conditions unless otherwise noted.
AOPA Pilot Editor at Large Tom Horne has worked at AOPA since the early 1980s. He began flying in 1975 and has an airline transport pilot and flight instructor certificates. He’s flown everything from ultralights to Gulfstreams and ferried numerous piston airplanes across the Atlantic.
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