Today’s Top Pick is a 1973 Cessna P337G Skymaster.

Pilots who wish to step up to multiengine aircraft from high-performance piston singles have options that offer a range of improvements in safety and performance.

While many private pilots looking for a boost in power will find turboprop singles more attractive than piston twins, having the redundancy of a second engine under certain conditions still means a lot to cross-country travelers.

Cessna designed the Skymaster series of twins with centerline-mounted engines that avoid the challenges of asymmetric thrust that come into play when an engine fails on a traditional light twin. As with any unusual configuration, some people love the Skymaster’s styling, while others are less enthusiastic. I imagine fans of the 1988 film Bat*21 would be absolutely stoked to fly a Skymaster.

The pressurized, turbocharged version for sale here makes the most of the aircraft’s performance potential by enabling it to take advantage of greater cruising speeds and favorable winds available at higher altitudes. Pilots who travel regularly with passengers, especially family members, are well aware of the advantages of a pressurized cabin.

This 1973 Cessna Skymaster has 2,500 hours on the airframe, 800 hours on the front engine since overhaul, and 12 hours on the rear engine since overhaul. The aircraft is equipped with Continental TSIO-360 engines. The front propeller has 800 hours, and the rear propeller has 12 hours. 

The panel features dual King KX 155 Nav/Comms, King audio panel, intercom, transponder and HSI, S-Tec 60 autopilot, Garmin GPS, and JPI 760 engine monitor.

Pilots who are interested in the advantages of twin-engine aircraft for long-distance travel, including the ability to continue flying if one engine fails, should consider this 1973 Cessna P337G Skymaster, which is available for $120,000 on AircraftForSale.

If you’re interested in financing, you can do so with FLYING Finance. Use their airplane loan calculator to calculate your estimated monthly payments. Or, to speak with an aviation finance specialist, visit flyingfinance.com.

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The post This 1973 Cessna P337G Skymaster Is a Push-Pull Pressurized ‘AircraftForSale’ Top Pick appeared first on FLYING Magazine.

Ampaire is the maker of the nine-seat Eco Caravan, which it claims to be the world’s largest hybrid-electric airplane. This week, the company announced it flew its Electric EEL demonstrator on a 12-hour, 1,375 sm (1,195 nm) jaunt out of Camarillo Airport (KCMA) in California—a feat it believes establishes an endurance record for hybrid-electric aircraft.

The firm said the demonstrator touched down with more than two hours of battery and fuel reserves remaining.

“Through this groundbreaking mission, Ampaire has shattered the conventional boundaries of electrified flight, underscoring our relentless pursuit of transformative vehicle performance and commercial utility,” said Ampaire CEO Kevin Noertker. “Our unique hybrid-electric solutions deliver unparalleled operating economics and unlock endurance and operational flexibility critical to our customer’s needs.”

The flight, which took place Sunday, comes just 17 months after a then-record 1,135 sm flight of the EEL from Camarillo to Wittman Regional Airport (KOSH) in Oshkosh, Wisconsin, which was validated by the International Air Transport Association (IATA).

Another manufacturer, Electra.aero, last month completed what it’s calling the “world’s first” flight of a hybrid-electric short takeoff and landing (STOL) design.

Ampaire’s EEL is a modified Cessna 337 Skymaster equipped with the company’s proprietary AMP-H570 AMP Drive: a hybrid-electric propulsion unit that’s also flying on its flagship Eco Caravan. The EEL is primarily a testbed aircraft, but the company says it can also serve owner-flown, charter, and short-haul regional airlines and carriers. The design boasts a 400 sm (348 nm) range and 450-pound payload capacity.

According to Ampaire, the EEL offers a larger payload than all-electric or all-hydrogen designs while enabling quicker infrastructure and certification timelines. It produces more emissions than all-electric models, but the manufacturer found that it achieved a 50 to 70 percent reduction in fuel consumption and emissions compared to traditional Pratt & Whitney PT6 turboprop engines.

The EEL Is the Real Deal

Ampaire described Sunday’s flight as the “crowning achievement” for the EEL. The demonstrator, the company’s second hybrid-electric prototype, first flew in 2020. Since then, it’s visited California, Arizona, Hawaii, Alaska, and Canada, often crossing state lines—and occasionally international borders—while picking up records and aviation firsts along the way.

The EEL’s first cross-country test flight between Camarillo Airport and Hayward Executive Airport (KHWD) came in 2020. Ampaire claimed the 2.5-hour, 341 sm (296 nm) trip was “the longest flight to date for any commercially relevant aircraft employing electric propulsion.”

Just a few months later, Ampaire partnered with Hawaii’s Mokulele Airlines to achieve another aviation milestone: the first trial of a hybrid-electric aircraft along an actual airline route. The project aims to demonstrate the island-hopping value of electric aviation. Not long after, the EEL made its debut in the U.K. hopping between Scotland’s Orkney Isles.

Then came 2022’s record-setting flight: a 1,135 sm (986 nm) jaunt from Camarillo to Oshkosh. But the company didn’t stop there.

In August, Ampaire flew the EEL to Alaska, which it said represented several firsts: the first hybrid-electric aircraft deployment in Alaska, first international hybrid-electric flight, and first aircraft to obtain special airworthiness approvals from regulators in both the U.S. and Canada. In November, it made the inaugural hybrid-electric flight into Palo Alto Airport (KPAO).

While the EEL is garnering headlines for its record-breaking demonstrations, Ampaire’s flagship Eco Caravan is flying too. The model is a modified Cessna 208B Grand Caravan with a 1,100 sm (956 nm) range and 2,500-pound payload. Last year, the company said it could be the first electrified regional aircraft to enter commercial service, with FAA certification expected in 2024.

Ampaire’s largest order for the Eco Caravan came in 2022 from U.K.-based lessor Monte Aircraft, which agreed to order up to 50 models. It also signed a deal with Azul Conecta, a subsidiary of Brazil’s largest airline by passenger volume, to convert six Grand Caravans in its fleet.

Behind the scenes, Ampaire has been working with NASA on several projects, most notably a collaboration to equip its propulsion system on its largest aircraft yet: a Twin Otter DHC6. It has an agreement with private charter operator WingTips for the conversion of 50 Twin Otters to Eco Otters—another Ampaire concept—in addition to 20 Caravans.

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Whether the demand for twins was a function of a real or perceived lack of engine reliability, or whether it was simply a sign of the industry taking advantage of robust demand for aircraft across all categories is unclear. But what is clear is that aircraft owners and operators had twin fever, and in the rush for market share, even smaller, more specialized companies like Helio responded to the demand and began designing twins.

Starting with their successful short takeoff and landing (STOL) Courier, Helio engineers removed the original engine and placed two 250 hp Lycoming O-540 engines on the wing. With nothing remaining in the nose, they cleverly solved one common challenge among taildraggers—poor forward visibility—by incorporating a helicopter-style bubble window in the nose.

To improve forward visibility even further, they also shrunk the instrument panel, relocating many gauges, switches, and the throttle quadrant to an overhead panel. This had the added benefit of placing engine-related controls and gauges closer to the engines themselves. When combined with the glass nose, the tiny panel afforded pilots outstanding forward visibility.

To maintain the single-engine Courier’s utility in challenging, off-airport operations, they retained the tailwheel configuration as well as the traditional Helio wing design. Utilizing large flaps and slats for better performance at high angles of attack, the wing also incorporated roll control spoilers that deployed with the ailerons to improve roll response at low airspeeds. Helio added a thin, slotted airfoil spanning the two engine nacelles to later models, reportedly to improve boundary layer control over the center section of the wing.

First flight took place in April 1960, and it quickly became evident the engineering worked. Helio touted a 320-foot takeoff distance over a 50-foot obstacle, though it is unclear upon what weight this was predicated. A 1964 evaluation flight by Air Progress, however, reported a takeoff ground run of only 250 feet at a light weight with a 7 mph headwind.

Other performance specs were similarly impressive. The FAA type certificate data sheet lists a single-engine minimum control speed (Vmc) of 59 mph, and Helio claimed a minimum speed of 35.7 mph. Rate of climb with both engines operating was said to be 1,600 fpm, and single-engine rate of climb, 310 fpm. Range was listed as 808 miles.

FAA type certification was awarded June 11, 1963, and Helio gave the Twin Courier a designation of H-500. Foreseeing military use, the U.S. Air Force assigned the designations U-5A and U-5B to the naturally-aspirated and turbocharged versions, respectively. But despite the certification and preparation, only seven examples would ever be produced.

The operational history of these seven aircraft is as unique as their appearance. While Helio publicly stated that all Twin Couriers were delivered to the CIA, they would go on to operate in clandestine operations under various entities of the U.S. military and government. Over their operational lives, some would be given USAF markings, while others would wear civilian paint schemes and civilian registration numbers. The N-numbers were registered to entities speculated to be shell companies for the CIA.

Tracing their operating missions, locations, and agencies is no small feat. Dr. Joe F. Leeker of the University of Texas, Dallas, has compiled what might be the most comprehensive history of the Twin Courier. In it, he traces the progression of each airframe through its respective history, noting that they saw service in Nepal, Bolivia, Peru, and the U.S. before being transferred to—and disappearing in—India. From there, the trail goes cold, and no Twin Couriers are known to exist today.

We can speculate, however. Given the rugged, remote areas in which the aircraft were known to operate, demanding airstrips and conditions likely claimed more than one aircraft. It’s plausible that one or more examples went down in inhospitable terrain and were swallowed by nature and the elements. Others were probably cannibalized for their rare parts. And given their shadowy history, it’s also possible that every trace of the type was intentionally scrapped and concealed from public view.

Considering the clever engineering and intriguing history of the Twin Courier, it’s unfortunate none exist today to be admired in person by future generations. Despite being certified by the FAA, it’s unlikely more will ever be built. In the meantime, we’re left with a small handful of photos, tiny scraps of unclassified U.S. government documentation, and a five-second cameo in the 1965 Jean-Paul Belmondo film, Up to His Ears.

Ultimately, the Twin Courier was an example of the long-standing effort to blend rotary-wing utility and fixed-wing speed, able to operate into and out of tiny, unimproved clearings while still providing relatively brisk cruising speeds. Today, tiltrotors fill the role admirably, but had the Twin Courier been given more of an opportunity to prove itself, it’s possible it would have provided similar functionality in a smaller and considerably less expensive package.

The post The Clandestine Legacy of the Helio Twin Courier appeared first on FLYING Magazine.

Ampaire’s Cessna Skymaster hybrid-electric test aircraft took its first flight in Scotland on Wednesday, positioning the airplane at the new UK-supported incubator for sustainable aviation at Orkey’s Kirkwall airport.

This is the second test aircraft for the company. It was modified in the U.S., with its first demo flights taking place in Hawaii.

The six-seat Skymaster—known for its tractor-pusher twin-engine configuration—has had its front engine replaced. This aircraft, N337EE, is in a different configuration from the first test aircraft flown in California in 2019, which had the rear engine replaced with an electric power unit (EPU).

The EPU used in the current Skymaster is capable of 200 kW output, though it’s limited in this application to 120 kW. The rear engine remains the standard 310-hp Continental IO-550.

The battery pack has been moved to a belly pod.

The Skymaster EEL was reassembled with the help of Wick Airport’s fire brigade upon the airplane’s arrival in Scotland. The demo flights are intended to highlight the low-emission profile and low operating costs anticipated when hybrid-electric aircraft hit their stride.

Ampaire expects the aircraft to have its best application on those routes now served by regional airlines.

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