The late 1950s and early ’60s saw a frenzy of aircraft development. Largely driven by military contracts that called for a specialized type dedicated to each role, variety abounded, and unique designs emerged to address the many military requirements of the era.

Cessna was no exception, and it took an interesting approach to developing a new model in September 1959. 

Historically, Cessna would modify civilian types for military use. For example, the 310 became the U-3, the 185 became the U-17, and the 172 became the T-41. In the case of the 407, the company reversed the process, using the existing T-37 “Tweet” primary jet trainer as a starting point and modifying it for civilian use. By installing new engines and modifying the cabin section, it aimed to convert the two-place military trainer into a comfortable, four-place personal jet.

There was some precedent for this new category of aircraft. Just seven months prior, French manufacturer Morane-Saulnier introduced the MS.760 Paris, a four-place jet with similar dimensions. With both military contracts and civilian sales secured, Morane-Saulnier appeared to have found multiple markets and would ultimately go on to build more than 200 examples.

Never one to happily cede market share, Cessna observed that it could pursue the blossoming personal jet market and also possibly secure some additional military contracts with minimum investment. By utilizing many of the same components and tooling as the T-37, much of the necessary development work could be avoided. Building a full-scale wooden mock-up and beginning construction of the first prototype, the marketing group began a sales tour, pitching the concept at various locations around the U.S.

Outwardly similar to the T-37, the 407 utilized the same tail section and wing as the jet trainer but repositioned the engine nacelles 9 inches outward to create more internal space. The cabin utilized this additional space to accommodate four passengers and their baggage. Occupants could easily step into the low-slung cabin without the need for separate steps or ladders, a welcome change from the MS.760, which required occupants to climb a stepladder and clamber into the cockpit from above—decidedly unsophisticated for the target customers of luxurious private jets.

Like the MS.760—but unlike the T-37—the 407 would incorporate a pressurized cabin for passenger comfort. This helped to enable a rather impressive service ceiling of 46,400 feet, some 13,000 higher than that of the French jet. At a more typical cruising altitude of 35,000 feet, the 407’s cabin altitude would have been maintained at a reasonable 8,000 feet.

Performance-wise, Cessna promised some fairly impressive numbers. With a 4,657-pound empty weight and 9,300-pound gross weight, the team boasted a range of 1,380 nm and a maximum level speed of 423 knots. The stall speed was listed as a relatively low 84 knots, making the jet capable of accessing runways of around 3,000 feet in length. 

Ultimately, like some other intriguing concepts from Cessna, the 407 was not to be. The mock-up pictured was, in fact, a T-37 with a wooden cabin section. And while construction of actual cabin sections was underway, the entire 407 project was abandoned in favor of the massively successful Citation family, the first of which flew in 1969. Interestingly, the FAA registry shows that Cessna registered a 407 as N34267, with serial number 627, indicating the project was full steam ahead, right up until the end.

The post Cessna 407: Full Steam Ahead, Right Up Until the End appeared first on FLYING Magazine.

Aerial application has historically involved creative solutions to address unique challenges. Whether the task at hand is crop spraying, pest control, or fire fighting, a multitude of capabilities are required to do the job safely and efficiently. Accordingly, the aircraft types utilized for these duties have evolved and adapted differently from most other categories of aviation.

The “Twin Cat” of the late 1970s and early ’80s was one such example. A development of the 1950s-era, purpose-built Grumman Super Ag Cat biplane, it replaced the Ag Cat’s single 600 hp Pratt & Whitney R-1340 radial engine with two 310 hp Lycoming TIO-540 flat-6 engines.

Rather than being offered as a complete, factory-built aircraft, the Twin Cat was a modification offered in the form of a supplemental type certificate (STC). The Twin Cat Corporation targeted Ag Cat operators wishing for more easily serviceable engines with increased overhaul intervals and multiengine redundancy, and the company offered to travel to the customer for on-site modification of their Ag Cats.

The company had some impressive experience at the helm. The president had overseen the development of a turboprop conversion of the Grumman Albatross and was assisted by the former chief test pilot at the general aviation division of Rockwell International. Most of the test flights were flown by Herman “Fish” Salmon, retired chief engineering test pilot of Lockheed. Salmon had conducted spin testing of the P-38 Lightning and had flown the first flights of the L-188 Electra, P-3 Orion, YF-104A Starfighter, and XFV-1 turboprop VTOL fighter. 

When designing the Twin Cat, one of the top priorities was to minimize asymmetric thrust in the event of an engine failure. The team did so by utilizing an unconventional engine layout in which the engines were mounted on either side of the nose with only approximately 3.5 feet between the propeller tips. The engines were also canted slightly outward to further minimize the effects of asymmetric thrust during single-engine operations.

The company touted benefits beyond the engines’ 2,000-hour TBO and better parts availability. While the engines were rated at 310 hp each, a sales manager said in an industry presentation that they derated them “with a pencil” and that the full 350 hp was available if needed. The Twin Cat’s total fuel consumption was the same as that of the single-engine radial Ag Cat. They also claimed the new layout improved forward visibility, prop clearance, and spray dispersion. 

When the time came for flight testing, the team got to see whether the new design could deliver the performance that backed up predictions. While the Twin Cat’s empty weight was the same as the Ag Cat’s, at 3,500 pounds, the maximum takeoff weight was 2,000 pounds higher, at 6,500 pounds. A load jettison function enabled the pilot to dump 2,000 pounds of payload if needed.

The new engine layout worked. With both engines operating, the Twin Cat’s takeoff distances were approximately 20 percent shorter than the Ag Cat. Asymmetric thrust was so effectively minimized that a sales manager claimed the Twin Cat could even take off with one engine shut down and then climb at 400 feet per minute at sea level. The company marketed this feature as a useful solution to ferry an aircraft with an inoperative engine to a location where maintenance could be performed.

In the air, the maximum cruising speed was 130 knots. By canting the engines slightly downward, the stall speed was remarkably low, at a claimed 49 knots for power-off stalls and 43 knots for power-on. A brochure claimed that the Twin Cat had “no V_MC,” which would have enabled flight all the way down to stall speed without controllability concerns. 

One account of the airplane’s flight characteristics suggests that it needed more refinement, however. It reportedly lacked any kind of rudder trim, and with an engine shut down, a pilot claimed he ran out of rudder and had to reduce power on the good engine to maintain control. It’s unclear whether the company planned to introduce rudder trim in future aircraft.

In the end, only three examples of the Twin Cat were rumored to have been completed and flown, and few photographs exist. One reportedly crashed, and the others presumably returned to their original single-engine configuration when the company decided against pursuing the concept any further. 

The post The One, Brief Life of the Twin Cat appeared first on FLYING Magazine.

It’s rare to find a twin-engine, piston-powered airplane with fixed-pitch propellers and nonretractable landing gear. In the post-World War II era, almost every piston twin utilized controllable-pitch propellers, both for efficiency and also so the pilot could feather a prop after an engine failure to reduce asymmetric drag and maintain control.

It’s also rare for an airplane to be optionally piloted—capable of flying both with a pilot aboard and also as an unmanned aerial vehicle. However, the Interstate TDR incorporated all these unique characteristics to fit a correspondingly unique set of mission requirements, specifically the ability to operate as a remotely piloted flying bomb. The “TD” portion of the designation signified “Torpedo Drone,” and the “R” was an arbitrary letter assigned to the Interstate Corporation.

• READ MORE: Cessna’s O-2TT Was Designed for Forward Air Control Missions

Compared to other manufacturing priorities during the war effort, the development of a relatively small fleet of unusual kamikaze machines was a low one. A previous attempt had been made with the Naval Aircraft Factory TDN, but it was reportedly found too expensive to manufacture and operate. Accordingly, the Interstate Corporation decided to tackle the project, aiming to find ways to improve upon the TDN.

The company got creative, awarding a contract for 200 tubular steel fuselages to the Schwinn Bicycle Company. It awarded a contract for the fabrication of wooden components to the Wurlitzer Company, a logical choice given its significant experience with manufacturing wooden pianos and guitars.

Interstate equipped the TDR with two 220-horsepower Lycoming O-435 horizontally-opposed, 6-cylinder engines. Later, three examples were fitted with more powerful Wright R-975 Whirlwind radial engines. Considering the TDR’s mission, it’s doubtful that multiengine redundancy was a primary factor in the decision to make it a twin. More likely, this layout was chosen to make room in the fuselage for the hundreds of pounds of radios and servos that enabled remote operation. Additionally, the lack of a nose-mounted engine makes that space available for a forward-looking camera.

Performance would have been modest, considering the TDR’s size and relatively low power. With a 48-foot wingspan and a maximum weight of 5,900 pounds, the airplane was comparable to the Beechcraft Twin Bonanza, yet had 150 fewer horsepower. Cruise speed was reportedly 140-150 mph with a 425-mile range. The TDR lacked brakes entirely, and thus, the takeoff procedure was rather unique. After lining up the airplane on the departure runway, ground crews would tether it to a stationary object such as a car or truck. After the pilot commanded takeoff power, the ground crew would cut it loose. 

• READ MORE: The Ryan YO-51 Wowed with STOL Performance

Although the landing gear was nonretractable, there was a way to eliminate landing gear drag entirely. For one-way missions that would result in intentional crashes into the enemy, the gear would be jettisoned immediately after takeoff, extending both speed and range. This would have opened a decidedly unique job position for ground crews—searching for and retrieving all the jettisoned TDR landing gear for use in future missions.

As part of a top-secret operation, Interstate brought in RCA’s chief scientist to adapt television technology to the aircraft. This enabled pilots to control the TDR remotely from airborne Grumman TBF Avengers. By referencing small TV screens, these pilots could fly the TDRs to targets several miles away and conduct attacks from the safety of their Avengers.

While the TDR proved capable of executing its remotely piloted flying bomb missions for approximately one year in 1944, its accuracy was less than impressive, and persistent developmental problems plagued the program. These issues, combined with the overall effectiveness of conventional weapon systems, ultimately led to the cancellation of the TDR after 195 examples had been built. 

• READ MORE: Flaris LAR 01 Still Has Potential

Interestingly, one TDR-1 was acquired by a private operator in Tulare, California, in 1959 with the apparent goal of utilizing it as an air tanker to help fight forest fires. This operator fitted a 200-gallon external tank on the belly of the fuselage and registered it with the civil designation N7790C. Its ultimate fate is unknown. Today, only one intact example survives, and it is presently on display at the National Naval Aviation Museum in Pensacola, Florida.

Portions of a second TDR also survive, including a large intact fuselage section, and are in the possession of a private individual in the U.S. With any luck, this person will be able to source and fabricate the necessary parts to complete a restoration.

The post Interstate TDR Developed as Unusual Kamikaze Machine appeared first on FLYING Magazine.

In the late 1960s, the U.S. was deeply entrenched in the Vietnam War and aircraft development was markedly different than it is now. Rather than shoehorning one type into myriad roles in an effort to reduce development costs, as is done today, the U.S. military leaned strongly toward the belief that it was better to develop unique aircraft types tailored specifically to each role. Aircraft manufacturers predictably rose to the challenge and constantly competed with each other in pursuit of new aircraft contracts, large and small.

Cessna was no exception. Beginning with the O-1 Bird Dog in 1949, the company went on to manufacture a number of other military aircraft, including the T-37/A-37 jet and military versions of the 172, 185, 310, and 337. In the year following the introduction of the militarized 337, known as the O-2, Cessna spotted an opportunity to create a modified version and wasted no time manufacturing a full-scale mockup.

Known as the Cessna O-2TT, the proposed aircraft was an intriguing blend of design elements collectively focused on forward air control missions. Using the O-2 as a starting point, Cessna replaced the 210 hp piston engines with 317 hp Allison 250 turboprops. This, Cessna predicted, would result in notably improved performance. 

In a November 1968 press release, Cessna listed the performance specs of the 3,220-pound (empty) O-2TT. Cruise speed at 75 percent power was listed as 174 knots and the rate of climb in standard conditions was listed as 2,160 feet per minute. The rate of climb with one engine out ranged from 710-795 feet per minute depending on which engine was shut down, but the specification sheet doesn’t articulate whether this is at the maximum (normal) takeoff weight of 5,000 pounds or the maximum (alternate) takeoff weight of 5,750 pounds. Useful load is listed as 1,780 pounds (normal) and 2,530 pounds (alternate).

More visually notable were the changes made to the fuselage. In an effort to provide the two occupants with unrestricted visibility, Cessna extended the forward fuselage dramatically, positioning each seat forward of the wing. Because the 138-pound Allison turbine engine was less than half the weight of the Continental piston engine it replaced, the repositioning of the forward engine would have been necessary regardless to maintain the proper center of gravity.

With both passengers moved forward, the change opened up ample space beneath the wing. Judging by the mock-up, enough space would be available for a third seat, but as the mission requirements only call for two occupants, it would instead be utilized for equipment and cargo. Given the additional fuel burn of the turbine engines, it could also be utilized for an auxiliary fuel tank to extend range and endurance.

To improve short takeoff and landing (STOL) performance, Cessna proposed modifying the wing as well. By increasing the span by over 4 feet and wing area by nearly 20 square feet, the wing would be notably larger than that of the standard O-2. Additionally, the O-2TT would incorporate high-lift devices to further improve STOL performance including a constant-radius leading edge and drooped ailerons interconnected with single-slotted flaps.

• READ MORE: The Ryan YO-51 Wowed with STOL Performance

The relatively straightforward and well-thought-out modifications used to create the O-2TT concept would likely have resulted in a formidable tool for use in forward air control missions. The improved, unrestricted visibility from each seat would have made the job easier for the occupants, the turbine engines would have improved performance and reliability, and the slow-turning propellers would have made the aircraft less noticeable to enemy units on the ground.

Unfortunately, the O-2TT concept never reached production, and the sole mock-up was presumably destroyed. In late 1969, the North American Rockwell OV-10 Bronco would enter service to fulfill the role—perhaps not coincidentally with twin turboprop powerplants, forward tandem seating with unrestricted visibility, and cargo space behind the two occupants.

The post Cessna’s O-2TT Was Designed for Forward Air Control Missions appeared first on FLYING Magazine.

In the late 1930s, the U.S. Army Air Corps (USAAC) determined it needed a specialized aircraft as a liaison and observation platform with exceptional short takeoff and landing (STOL) capability. This was perhaps inspired by the Fieseler Storch performing many of the same duties for the Luftwaffe. The Storch excelled in its role, using a 240-horsepower inverted V-8 to pull a kite-like wing through the air and providing takeoff and landing distances of less than 200 feet.

The USAAC sent bids for such an aircraft to multiple manufacturers. The ensuing competition ultimately came down to three, each building three prototypes in 1939 for the contract. Bellanca responded with the YO-50, a high-wing taildragger with an enclosed tandem cabin powered by a 420-horsepower Ranger inverted V-12. Stinson responded with their L-1 Vigilant, an aircraft of similar design but with a more traditional 295-horsepower Lycoming radial engine.

Ryan’s offering was the YO-51 with a company name of “Dragonfly,” and it incorporated a few unique features that made it stand out from the other two contenders. Rather than being equipped with an enclosed and glazed cabin, the Ryan utilized an open cockpit beneath a parasol wing. While doing away with a cabin altogether makes for an effective observation platform by eliminating a number of blind spots, one wonders how effective the airplane would be in frigid northern climates with cold and fatigued crew members.

The Ryan’s landing gear was quite different from the others but nearly identical in design to the Storch. While the YO-51 differed by integrating the wing strut into the design, both the Ryan and the Storch utilized an extremely wide stance and long-travel suspension. In the case of the Storch, it provided a plush 16 to 18 inches of suspension travel to soak up all but the most violent landings. 

In addition to being a parasol design, the Ryan’s wing incorporated full-span leading-edge devices. Publications differ in their description of them, randomly referring to them as slots, which remain fixed in position, and slats, which move between retracted and extended positions in flight. The publications can perhaps be forgiven, however, as photos exist showing both variants installed on different YO-51s.

Ryan chose full-span Fowler flaps for the trailing edge, a then-revolutionary design utilized by Lockheed on the 14 Super Electra and later on most high-wing Cessna models. Notable for introducing primarily lift in the first segment of travel and then drag at higher settings, these flaps helped to enable exceptional STOL performance, particularly when they make up the entire trailing edge of the wing. To provide roll authority in the absence of traditional ailerons, Ryan equipped the YO-51 with roll-control spoilers.

To the delight of U.S. Army Air Forces (USAAF) maintenance technicians, Ryan eschewed inverted V engines and instead opted to use a common and known engine, the Pratt & Whitney R-985 Wasp Junior radial. Producing 440 horsepower for the YO-51, this engine was also utilized in the Beech 17 and 18 as well as the de Havilland Beaver and Vultee BT-13 Valiant. With almost 40,000 built over the years, Ryan must have touted their engine choice as far more sensible than Bellanca’s.

The three YO-51s, wearing serial numbers 40-703, 40-704, and 40-705, first flew in 1940 and predicted performance was achieved in flight testing. Hard data is sparse, but multiple sources report the 4,200-pound airplane could take off in less than 100 feet and clear a 50-foot obstacle in slightly less than 500 feet. Landing over a 50-foot obstacle reportedly required 400 feet. 

When it came to speed, the complex wing enabled a broad operating range. Stall speed was reportedly only 30 mph, while cruise speed was a healthy 107 mph. These numbers were nearly identical to the Storch…and, perhaps not coincidentally, also nearly identical to the Bellanca and Stinson with which it was competing. 

During some of the first test flights, spectators were wowed by the performance. An article in a Ryan company newsletter reported that during one takeoff, the YO-51 “leaped into the air after a run of only 50 feet, pointed its nose at a 60-degree angle, rose almost vertically and remained virtually motionless over the airport.”

The March 15, 1940, edition of the Air Corps Newsletter described the YO-51’s flight capabilities in an even more colorful manner, observing, “The first model of the YO-51 has been grasshoppering in our midst and is doing things that have reduced our carefully nurtured conceptions of how an airplane flies to a pile of ashes.”

Despite such impressive grasshoppering, the USAAC competition was ultimately awarded to Stinson. During its production run, some 324 examples of the O-49 (later L-1) were built for the U.S. and the Royal Air Force.

Sadly, no trace of the three YO-51s nor the three Bellanca YO-50s remains today. One account reports that the three YO-51s were utilized as “ground instructional airframes,” and it’s likely that all six contenders were ultimately scrapped at some point thereafter. 

The post The Ryan YO-51 Wowed with STOL Performance appeared first on FLYING Magazine.

Among the wide variety of aircraft categories that have emerged from the drawing board over the decades, one has consistently captured imaginations but also consistently failed to flourish. It’s a category that has, from its inception, promised unparalleled freedom and performance in a personal-sized package. Sometimes referred to as “mini-jets,” these are loosely defined by having two to four seats and being powered by one or two jet engines.

Like grand-touring automobiles, these personal jets have targeted the well-to-do traveler, intent on covering sizable distances with a companion and some luggage. At the same time, manufacturers hedged their bets by touting the category’s suitability for limited military roles, such as training and utility duties.

Few mini-jets ever reached series production. French manufacturer Morane-Saulnier saw some success with its MS.760 Paris jet in the 1960s. More recently, Eclipse Aviation flew its Concept Jet prototype but, like most other modern efforts, ultimately settled on a larger six-place design.

Polish manufacturer Flaris appears to be the only company with the potential to buck the trend and bring its contender to production. Naming it the LAR 01, Flaris introduced the small, 4,079-pound (maximum takeoff weight), single-engine jet in 2013 and conducted the first flight in early 2019. While it technically has five seats, it is perhaps more accurately described as a four-plus-one, as, like a sports sedan, the fifth seat is nestled between the two back-seat passengers.

The overall airframe layout is logical. The single Williams FJ33-5 engine needs to be placed on centerline, and to avoid robbing internal volume with the engine and ducting, Flaris followed the lead of Eclipse and Cirrus with a dorsal engine pod. To separate the LAR 01’s tail surfaces from hot engine exhaust, Flaris opted for a “U-tail” with two small vertical stabilizers at each tip performing yaw duties. 

Whereas the overall airframe layout is predictable, the execution is intriguing. Flowing lines define the fuselage, from a constant arc along the belly to the organic window and door shapes up front. Faced with the decision to retract the main gear into the wing or the lower aft fuselage, Flaris opted for the latter, enabling a thin, efficient wing design.

Flaris touts an 18-to-1 glide ratio, besting the 14.7-to-1 ratio of the Cirrus Vision Jet and actually matching that of early Schweizer gliders. This abundance of aerodynamic efficiency also provides healthy returns during takeoff and landing. The LAR 01 requires just 656 feet to take off and 820 feet to land. Interestingly, Flaris has designed and approved the jet for operation from grass fields, a feature not commonly seen among jet-powered aircraft that aren’t built by Pilatus.

The stall speed of the LAR 01 is a meager 62 knots, enabling the pilot to dissipate a significant amount of energy prior to touchdown in the event of a forced landing. Alternatively, they can deploy the parachute as in the Cirrus.

Rather than utilizing a traditional thrust lever mounted atop a center console, Flaris has installed a single control stick in that position, with dual thrust levers mounted on both outside edges of the glareshield. Accordingly, each front-seat passenger would use their inside arm to control the jet and their outside arm to actuate their thrust lever.

To date, only one LAR 01 has been built, and it appears to be progressing through flight testing. However, a second airframe has been completed as an unmanned aircraft and was displayed at the 2023 Dubai Airshow following a United Arab Emirates defense firm purchasing a 50 percent stake in Flaris. Whether that deal will affect the development and certification of the LAR 01 remains to be seen.

The post Flaris LAR 01 Still Has Potential appeared first on FLYING Magazine.

Among the world’s aircraft manufacturers, Pilatus has historically demonstrated prudence and restraint with regard to its product offerings. While certain competitors embrace constant expansion, branching into emerging niches with new aircraft models spanning a variety of categories, the Swiss company has taken a careful, measured approach.

Between the 1950s and 1980s, for example, the company only pursued two categories: utility taildraggers and single-engine military trainers. While it also dabbled in gliders with the B4/PC-11 in the mid-1960s, its engineless offerings never expanded beyond that one model. It wasn’t until the late 1980s that the PC-12 business turboprop emerged from the factory in Stans, followed by the PC-24 business jet in 2015.

Along the way, however, Pilatus did explore many interesting concepts. And although the PD-01 Master Porter (stylized in marketing materials as ‘MASTER-PORTER’) shown here was never flown, it stood out as one of the more ambitious. Developed shortly after the introduction of the CASA C-121 Aviocar, it shared many of the same characteristics, such as a high wing with two turboprop engines, a rear cargo ramp, and STOL capability. It also targeted the same market as the CASA, highlighting capabilities such as air ambulance, aerial photography, and military airlift operations.

Focusing heavily on utility, Pilatus ensured the 16,534-pound (maximum takeoff weight) Master Porter would be adaptable to a wide variety of missions. It designed the cabin with the ability to be changed in less than 15 minutes from passenger to cargo or a combination of the two. The cabin could seat up to 26 passengers in a 2-2 configuration, 21 in a 2-1 configuration, or up to 5,950 pounds of freight. The aft cargo ramp would ease cargo loading and unloading while providing a platform for various military operations.

Additionally, up to three LD3 cargo containers could be loaded in lieu of passengers. This capability would prove valuable to the market segment for years to come, with Cessna maintaining and touting the ability of its SkyCourier to also carry three LD3 containers when it was introduced in 2022.

Pilatus ensured the Master Porter would be as adaptable to landing sites as it was with cargo. The landing gear was unique, overbuilt to enable operation from unimproved surfaces but with a retractable nose wheel to reduce drag and provide a bit more cruise speed. Skis could be fitted for snow operations, and floats would enable water operations.

Living up to its heritage, Pilatus also engineered healthy short takeoff and landing (STOL) performance into the Master Porter. Through the use of 1,110-hp Pratt & Whitney PT6A-45 engines and effective high-lift devices, takeoff distance at maximum takeoff weight required only a 950 feet ground run and 1,690 feet to clear a 50-foot obstacle, with 870-foot and 1,480-foot landing distances, respectively. With a healthy 55-degree maximum flap setting, stall speed was only 70 knots, yet the aircraft was promised to achieve 205 knots in cruise.

Pilatus presented the Master Porter to the public in Munich in 1974 and constructed cockpit and fuselage mock-ups for marketing purposes. But whether the project garnered insufficient interest or the company determined the market niche was too saturated with the CASA C-212, Let L-410, Short Skyvan, and IAI Arava, the concept was abandoned shortly thereafter. It’s possible Pilatus was giving up on a promising opportunity. But it’s perhaps more likely the company was taking its typically careful, prudent approach to expansion, opting instead to dedicate its resources to the refinement and support of existing models.

• READ MORE: The Fizzled-Out Promise of the Lockheed ‘Flatbed’

The post Pilatus PD-01 Master Porter Was an Ambitious Concept appeared first on FLYING Magazine.

It’s not uncommon for a family to have that one “crazy uncle” whose background raises more questions than answers. Maybe it was legal trouble back in the 1960s, an adventure as a band groupie spanning multiple continents, or perhaps some harebrained business venture involving unspecified imports and exports.

In the Luscombe family, that crazy uncle is the unique T8F. At first glance, it appears quite similar to the traditional Luscombe 8 taildragger. Most parts are common, after all, and the wing, landing gear, engine, and tail are almost indistinguishable from the standard model.

• READ MORE: The Luscombe 8 Offers a Unique Trip Back in Time

Setting it apart, however, is an entirely different passenger cabin and seating arrangement. Rather than the standard Luscombe’s tight, side-by-side seating, the T8F uses a tandem configuration, placing one seat in front of the other. The aft occupant is provided with a massive bubble canopy that extends above the wing and provides a panoramic view around the airplane.

Why did Luscombe develop such a derivation of the successful standard version? To compete for a military contract—specifically one with the U.S. Army for a liaison aircraft. Luscombe reasoned that with a minimum amount of engineering effort the modified version could perform the role and increase sales.

When Aeronca won the contract, Luscombe was left with a unique model that was fully flight tested but lacked clear direction. It offered legitimate operating economy and outstanding visibility from the rear seat, and it would surely be perfect for certain applications. Looking to make the most of the opportunity, the company put its marketing team to work. 

Before long, Luscombe presented two versions of the T8F for the civilian market. The standard version, marketed as the Silvaire Observer Special, targeted such duties as pipeline inspection and aerial observation. The Silvaire Sprayer incorporated larger tires, flaps, and spray equipment for aerial application duties.

Luscombe claimed the Sprayer was the first production airplane to be factory designed and engineered specifically for aerial crop spraying. While the accuracy of this claim might rely on nuance with specific wording and definitions, it’s safe to say that the type bridged the gap between early modified types, such as Stearmans, Huff-Daland Dusters, and later types that were legitimately purpose-built from the ground up for agricultural duties, such as the Snow S-2 and Fletcher FU-24.

Of the roughly 100 examples produced, 25 remain on the FAA registry. Several examples, such as the one pictured in this article, sport a military livery. While no T8F served in any branch of the military, the colors shed light on what might have been had the type been selected over the Aeronca so many years ago.

As a pseudo-warbird, a T8F would be relatively easy to own. With most parts common to the far more plentiful standard Luscombe models and simple, straightforward systems, it would present few headaches or pitfalls compared to other types. Additionally, the unique tandem seating affords larger pilots the shoulder room and cabin width necessary to fly a Luscombe in relative comfort. 

Best of all, the T8F offers a glimpse into a little-known footnote of aviation’s past. Like that crazy uncle with an unusual background and bizarre stories to tell, the T8F provides an intriguing history lesson and captivates audiences wherever it goes.

The post The T8F Is Luscombe’s ‘Crazy Uncle’ appeared first on FLYING Magazine.

In the 1970s, the jet age had firmly taken hold of most categories of aviation, and jet power was quickly becoming the norm. From airliners to fighters to private jets, nearly every category took advantage of the increased power, speed, and reliability of jet engines. But while the benefits were numerous, fuel consumption was quite high, and by the middle of the decade, the cost of jet-A had tripled.  

The cost to train pilots in advanced jet trainers, therefore, was following suit. One company in Germany spotted an opportunity for a more cost-effective alternative. If it could design an advanced trainer that was drastically less expensive to operate, it reasoned it would be of interest to militaries around the world.

The company was Rhein Flugzeugbau (RFB), and by starting with a clean-slate design, it proposed an entirely new aircraft called the Fantrainer. It would utilize a ducted fan nested within the empennage, and the forward section and cockpit would closely resemble operational jet fighters. By driving the ducted fan with one small turboshaft engine, fuel consumption would be dramatically reduced compared to pure jets. When combined with an airframe optimized for training and low manufacturing cost, RFB was confident the aircraft would sell well.

Developing a cost-effective advanced trainer wasn’t a new concept. Other manufacturers had pursued the military trainer market with single-engine turboprops, such as the Pilatus PC-7 and Beechcraft T-34C Turbo-Mentor. These had secured many military contracts, but the traditional propeller configuration provided handling and flight characteristics quite unlike the jets for which they were preparing their pilots. By integrating the ducted fan within the aft section of fuselage, RFB successfully eliminated virtually all of the left-turning tendencies of a single-engine turboprop and offered an advanced trainer with handling that was a much closer approximation to tactical jets.

The secret was in the shroud. Larger, conventional propellers come with distinct limitations— propeller efficiency drops off dramatically beyond a certain rpm, for example, limiting the maximum allowable rpm. By utilizing a small fan under 4 feet in diameter, it could be turned at a higher rpm, and the shroud can act as winglets do on wingtips, increasing efficiency even further. Additionally, sufficient propeller clearance requires longer, heavier landing gear, so the small fan permitted a more compact gear design.

For these benefits to be realized, however, tip clearances have to be tiny—in the case of the Fantrainer, about 2 millimeters—and this requires an extremely stiff structure. To achieve this, RFB designed the empennage around thin vertical and horizontal sections joined by the circular shroud. FLYING’s Peter Garrison wasn’t impressed, observing, “It would be difficult to imagine a less promising structural arrangement. Its numerous surfaces and intersections threaten to multiply sources of drag, while its peculiar load paths and concentrations do the same to weight.”

Performance was, therefore, underwhelming. RFB would ultimately manufacture two versions of the Fantrainer, and the more powerful 650 hp version would only achieve a 225-knot maximum speed—barely more than the aforementioned turboprop trainers, each with 100 less horsepower. And while the Fantrainer did indeed mimic the handling and feel of a jet, it came at the cost of unique, proprietary parts and systems that would introduce complexity to maintaining a fleet.

Accordingly, only 50 examples were built. These were delivered to the Luftwaffe and Royal Thai Air Force. In an attempt to expand and diversify its offerings, RFB teamed up with Grumman American to market the Fanliner, a futuristic two-seat light aircraft that paired a smaller ducted fan with a 114 hp twin-rotor Wankel rotary engine. Only two examples would be built.

Despite the limited sales, however, there remains a sliver of hope for the Fantrainer. In 2010,  German company FanJet Aviation GmbH bought the certification and tooling and is presently marketing it for military and civil training purposes. Unfortunately, the last news update on the company’s website was posted in July 2022, and no production orders appear to be forthcoming.

The post The RFB Fantrainer Turboprop Was Meant to Handle Like a Jet appeared first on FLYING Magazine.

Imagine, for a moment, that you are a young engineer in the early 1960s, fresh out of college and looking for your first job. Luck smiles upon you, and you’re offered a job at Convair, manufacturer of a wide variety of aircraft from interceptors to fighters to airliners. As you report for your first day of work with visions of the magnificent XB-70 Valkyrie strategic bomber streaking through your head, you are informed that you’ll instead be assigned to an odd little turboprop with a top speed of 277 knots. 

After coming to terms with the lowly assignment, some closer investigation would have likely cheered you up. The aircraft would be called the Model 48 Charger, which would be Convair’s entry into a competition against eight other manufacturers. Each would create a clean-sheet aircraft proposal to fulfill a contract in which the U.S. Army, Marine Corps, and Navy would ultimately be involved.

The Charger would be required to take off from an aircraft carrier without catapult assistance. It would also be required to operate on floats and from unimproved runways while carrying six troops in addition to the pilot. It was a unique blend of technical requirements. While the project perhaps lacked the prestige of the company’s supersonic offerings, it presented some challenges that must have been intriguing to every engineer assigned to it.

Compared with the proposals from companies like Grumman, Beechcraft, and North American, the Charger stood out with a shockingly stubby wing. While the aircraft itself was not diminutive, with a maximum takeoff weight of more than 10,000 pounds and two 650 hp Pratt & Whitney PT6 turboprops, the King Air-sized machine sported a wingspan only 3 feet greater than that of the 1,100-pound Grumman AA-1. Even after a wing extension early in the test program, the wingspan remained 3 feet less than a Cessna 150.

The secret was prop wash. The wing was designed in such a way that nearly all of it was blanketed in the prop wash from each engine. Because the local wind velocity enveloping the airfoil was therefore accelerated, the wing was able to produce lift at lower indicated airspeeds. Bolstering this performance were flaps that were as long as the wing and extended to an extreme 90 degrees for landing. Inboard Kruger flaps, not unlike those on the Boeing 727, adorned the leading edge.

This resulted in shockingly impressive takeoff and landing performance. Janes’ All the World’s Aircraft lists the Charger’s takeoff and landing distances as each being less than 500 feet. Even more impressively, this is listed as the distance required to clear a 50-foot obstacle. While no conditions or parameters were listed, the numbers are impressive, even if little to no payload was necessary to achieve them.

Depending on engine thrust to maintain so much of the wing’s lift was clearly effective. But like a blown wing, an abrupt loss of engine thrust below a certain airspeed would result in a stall. Should just one engine or propeller fail at a low airspeed, an irrecoverable loss of control could occur.

The final product resembled a clipped-wing OV-10 Bronco, with a twin-boom tail, long-travel landing gear, and a canopy that offered nearly unlimited visibility. Like the Bronco, the tail cone could be opened to reveal a small cargo area. This area was proposed to be used for troops and stretchers.

Intended to fulfill various roles, the Charger was also equipped with ordinance. Four machine guns and five hardpoints could be used for counterinsurgency (COIN) missions. Drop tanks could also be fitted to provide a 2,600 nm ferry range.

Although Convair hustled to take the Charger from paper to first flight in only 40 weeks, the company’s efforts would be for naught. In October 1965, while on its 196th test flight in San Diego,, a test pilot crashed the lone prototype, sustaining serious injuries and damaging the aircraft beyond repair. The exceedingly sparse National Transportation Safety Board report stated that the “military test pilot used improper [engine] shutdown procedures [that] caused [generator] reduction gear pinions [to] seize.”

The report indicates an engine failure occurred, and under “Phase of Operation,” it lists two phases—normal cruise and go-around. Assuming the initial engine failure occurred during cruise and the accident occurred during a go-around, the unconventional engineering that enabled the Charger’s outstanding performance might have contributed to its demise.

The post Convair Model 48 Charger Featured Stubby Wings appeared first on FLYING Magazine.

The World War II era was an interesting time to be an aircraft engineer. Piston-engine technology was reaching a pinnacle of power and complexity, huge design and production demands were incoming from the war effort, and the advent of jet power had just emerged. It was a time to push up sleeves, sharpen pencils, and push boundaries.

This was certainly the case at Douglas Aircraft Co. When approached by the military to develop a small bomber that prioritized speed, Douglas responded with the XB-42, nicknamed “Mixmaster”—a decidedly unconventional, piston-powered design that it promised would achieve nearly 500 mph. When the military gave the go-ahead to build and fly two prototypes, it was up to the engineers to deliver the extreme performance.

To accomplish this, they focused on eliminating as much extraneous drag from the wing and airframe as possible. Rather than installing the two 1,800 hp Allison V-1710s (as used in the Bell P-39 Airacobra, Lockheed P-38 Lightning, Curtiss P-40 Warhawk, and others) in individual, wing-mounted nacelles, both engines were entirely housed within the aft fuselage. This kept the wing completely clean, without any of the parasite or interference drag inherent in the traditional nacelle configuration.

The engineers then developed a system of six individual drive shafts to link the engines to an aft gearbox, which drove a pair of three-bladed pusher propellers. The propellers were electrically controlled and able to feather, and the aft propeller was capable of adjusting its pitch even farther, providing reverse thrust. The feathering capability would be used later in the test program when one of the two engines would fail in flight.

The configuration didn’t deliver quite as much speed as Douglas had hoped. At 23,440 feet, the XB-42 could only achieve a maximum speed of 410 mph, and its cruise speed settled at 312 mph. Admirable numbers for a piston-powered bomber, but still well short of the company’s targets.

As other aircraft designers would also learn, pusher propellers located at the extreme aft end of the airframe create new and unique problems. Rotating too sharply during takeoff and flaring hard during landing, for example, would result in prop strikes. Douglas solved this by adding a ventral vertical stabilizer with an integrated shock absorber to isolate the airframe from the blows of tail strikes.

Another concern was the well-being of the flight crew in the event it became necessary to bail out of the aircraft. To prevent it from the grisly fate of entering two counter-rotating prop arcs after jumping, Douglas made it possible for the crew to first jettison the propellers and aft gearbox with an explosive charge. Instantly dumping more than 1,000 pounds from the extreme aft end of the airframe would wreak havoc on the center of gravity and produce a violent, nose-down pitching tendency.

One crew would experience this firsthand when it was forced to bail out during a test flight in December 1944. This crash would result in the loss of one of the two XB-42s. The remaining example would go on to fly in its original form and was later modified with two underwing turbojet engines, becoming the XB-42A.

Ultimately, the design would shed its propellers entirely and evolve into a pure jet when the static test airframe was developed into the jet-powered XB-43 Jetmaster. The sole surviving XB-42 awaits restoration at the National Museum of the U.S. Air Force in Dayton, Ohio.

The post The Douglas XB-42 ‘Mixmaster’ Flew Almost as Fast as It Looked appeared first on FLYING Magazine.

Generally, the more unique and unconventional an aircraft’s design, the more extreme its strengths and weaknesses become. A canard configuration, a wing optimized for high lift, and an amphibious airframe each provide specialized capability, and each also introduces a corresponding penalty with regard to other factors. This give and take in aircraft design and engineering applies to all aircraft, from the largest transports to the smallest homebuilts. 

Among the most interesting case studies are those that start with a common mission and reimagine the ordinary, eschewing the tried and true in favor of exploring new concepts. The Anderson Greenwood AG-14 is one such example. Aiming to gain a foothold in the personal aircraft market during the postwar years, it incorporated a decidedly unconventional layout that featured a single pusher engine and a twin-boom tail.

The fundamentals of the aircraft were common to existing types, however. Like many Cessna 140s, Luscombes, and Ercoupes, the AG-14 was equipped with a run-of-the-mill Continental C90 engine and a fixed-pitch propeller and weighed less than 1,000 pounds (empty) with a two-person capacity. This commonality of these foundational elements effectively isolated the pros and cons of the unique airframe layout, enabling an interesting side-by-side comparison with conventional types.

The most significant benefit of the unorthodox design was the completely unrestricted visibility from the cockpit. With no wing creating a blind spot either upward or downward, no engine cowling limiting forward visibility, and no propeller arc through which to look, the occupants’ field of vision is not unlike that of some helicopters. Indeed, had the design been given the opportunity to evolve, some panel reconfiguration could have enabled the introduction of a fully glazed forward cockpit like the Partenavia Observer. Such a modification might have appealed to the market as a low-cost helicopter alternative for duties such as pipeline inspection, law enforcement, and aerial survey missions.

A secondary benefit to the design is the configuration of the propeller and tail. Completely nested within the tail booms, the pusher propeller is shielded from wayward pedestrians who might carelessly wander around the airplane. Although the pilot cannot visually confirm the prop is indeed clear before engine start, the safety benefit of its position within the tail booms is legitimate.

Chief among the disadvantages of the AG-14’s layout is weight and balance. When it comes to aircraft design, it’s preferable to position the location with variable weight (such as fuel tanks and the passenger cabin) as close to the center of gravity (CG) as possible. This minimizes the effect varying weights will have on the CG, simplifying the concern of staying within that envelope. 

By positioning the passenger cabin well forward of the wing (and CG), the AG-14’s design introduces some unique characteristics. With little effort, one person can lift the nose wheel up and tip the airplane back onto its tail. Pilots report that the nose wheel can be held off the ground indefinitely while taxiing, even at low speeds. While Anderson Greenwood sufficiently addressed any issues related to this aft CG to achieve type certification, it was undoubtedly a major concern during the design and certification phase. It’s possible the decision to limit pitch authority and make the airplane stall and spin resistant was a decision driven by the negative effects of a particularly aft CG in stalls and spins.

The additional structure and complexity of the twin-boom tail inevitably add additional weight compared to conventional tails. This naturally limits useful load, adds drag, and makes inspections and maintenance more complex. Nevertheless, Anderson Greenwood managed to achieve performance comparable to the Cessna 150, with a cruise speed of 110 mph and a climb rate of 630 feet per minute. One minor downside with which the Cessna doesn’t contend is related to the pusher configuration—positioned directly behind the nose wheel, the propeller is susceptible to damage and wear from foreign object debris.

The AG-14’s design was intriguing enough to inspire a derivation in the form of the Cessna XMC research aircraft. First flown in 1971, Cessna studied the nearly identical side and configuration in pursuit of noise reduction and improved visibility for personal flying and training purposes. Ultimately, only one example was built, and Cessna did not pursue the concept any further.

After being introduced in 1950, only five AG-14s were produced. Today, four remain on the U.S. registry, and at least one or two are maintained in flying condition. Occasionally, one of the owners attends fly-ins like EAA AirVenture in Oshkosh, Wisconsin, where one can see and admire the unique little airplane in person. While it is unlikely the design will reemerge in the form of a modernized version, advanced materials such as carbon fiber could enable further evolution of the concept.

The post Anderson Greenwood AG-14 a Rare Breed, Indeed appeared first on FLYING Magazine.

In 1980, a small team of engineers from Lockheed explored a bizarre concept, the likes of which had never been studied before.

The group recognized that the transport aircraft category traditionally comprised three separate subcategories—passenger, cargo, and outsized cargo. It then created a concept that would combine all three. Aptly called the “Flatbed,” the concept aircraft would utilize an open platform and various modules to carry a wide variety of loads ranging from military equipment to passengers.

• READ MORE: The Unconventional, Bizarre Bell Airacuda

The most unconventional aspect of the Flatbed was the proposal that large pieces of military equipment be carried out in the open, completely unsheltered from the wind and elements. The team selected two sample military vehicles for the initial study, an XM-1 tank and an M60 bridge launcher, weighing 115,000 and 120,000 pounds, respectively. The big question was could this sort of outsized cargo effectively be carried out in the open at hundreds of miles per hour?

The group got to work on the drawing board and in the wind tunnel to answer that and explore how the Flatbed might serve as a multifunctional, “do-it-all” transport solution. The baseline Flatbed aircraft was a low-wing, turbofan-powered aircraft approximately the same size and weight as an Airbus A300. It utilized four CFM-56 engines, as found on the Airbus A320, Boeing 737, and Boeing KC-135R Stratotanker, and was optimized for a 2,600 nm range.

• READ MORE: That Time Cessna Made a Helicopter

Recognizing that carrying outsize cargo such as tanks out in the open would present serious drag and fuel-burn penalties, the team did not hedge its bets on this configuration alone. Instead, it designed the Flatbed to accept a variety of pressurized and unpressurized containers as well as a passenger module. The entire nose section of the aircraft was hinged, capable of being swung to the side to enable modules and vehicles to be quickly and easily loaded and unloaded using a variety of ramps, rollers, and latches. Raised engine pylons extending above the wing rather than below enabled shorter landing gear and a low, 7-foot cargo bed height.

With the cargo and passenger modules, the Flatbed was shown to be “generally fuel efficient in comparison with reference airplanes,” burning approximately 11 percent more fuel than a conventional design and targeting a 0.82 Mach cruise speed in these configurations. The primary benefit was presented as efficiency with regard to loading and unloading, particularly in the passenger configuration. In this role, the team proposed an entire restructuring of point-to-point travel.

• READ MORE: The Close Call of the Northrop YA-9A Prototype

By utilizing a large number of removable 180-seat modules, the passengers could board their module in a city center some distance away from their departure airport. Like multimodal containers, the module could be loaded onto a short-distance commuter train for transport to the airport, where it would be expeditiously loaded onto the waiting aircraft. The team proposed that this speedy loading and unloading of passengers would enable quick turns and high aircraft utilization. Similarly, it touted the ability of multimodal containers and even train cars to be quickly rolled onto and off the Flatbed.

But from the perspective of aircraft design in general and aerodynamics in particular, the most intriguing aspect of the Flatbed concept was the carrying of outsize cargo out in the open. Using scale models of both the Flatbed and tank and bridge launcher, aerodynamicists studied drag figures and later translated the data into speed and fuel-burn figures. The resulting performance numbers indicated the concept was surprisingly plausible.

Naturally, carrying external cargo was found to drastically increase drag compared to carrying the aerodynamically slick cargo and passenger modules. At higher altitudes, carrying the tank or bridge launcher would result in a 20 percent increase in fuel burn. At a lower 18,000 feet cruising altitude, this increased to approximately 55 percent. The external cargo also lowered the cruise speed to 0.5-0.6 Mach.

The team proposed multiple solutions to address the increased fuel burn. At the time of the study, engine manufacturers were looking at unducted “propfan” engines to improve fuel efficiency, and the team suggested exploring these new engines for the Flatbed. It also explored the possibility of “vortex control,” a system that introduced suction at the forward end of the cargo bed to smooth the air flowing around the back of the cockpit section, thus reducing drag. 

Ice accumulation on external cargo was identified as one potential challenge worthy of additional study. Engineers did observe that in-flight icing “does not appear to present a major problem,” however, as ice formation occurs only on the front part of the aircraft components. By tucking in the external cargo behind the cockpit section, it appeared to be sufficiently shielded from ice. 

While the Flatbed concept would never materialize beyond static and wind-tunnel models, the team partnered with NASA to publish a detailed initial study that evaluated the feasibility of the unconventional concept. The study ultimately concluded that the concept was both technically and economically feasible. They reasoned that the smaller size and increased versatility of such an aircraft would make it inherently more efficient to operate compared to existing military cargo aircraft.

Despite the overall finding that the Flatbed concept was worthy of additional examination, however, no such study ever occurred. The Lockheed Flatbed concept fizzled out after the publication of the NASA report.

The post The Fizzled-Out Promise of the Lockheed ‘Flatbed’ appeared first on FLYING Magazine.

Larry Bell, founder of the Bell Aircraft Corp., now known as Bell Helicopter, entered the aircraft manufacturing industry with a unique bang. After dropping out of high school in 1912, Bell worked for various aircraft companies, including Martin and Consolidated, before starting his own company in 1935. Rather than beginning with a conservative, basic aircraft type, he opted to respond to a military contract by proposing one that was so unconventional it bordered on bizarre.

That aircraft was the Bell YFM-1 Airacuda, a long-range and heavily armed escort fighter designed as an interceptor and bomber escort. It was part of a newly emerging category of aircraft containing models described by FLYING in 1941 as “virtually impregnable fortresses of themselves, yet maintaining considerable maneuverability and striking prowess which the big bombers lack.”

The design and configuration of the Airacuda was like nothing the industry had ever seen. The twin pusher engines were housed in glazed nacelles, each of which contained a crewmember, for a total of five. And while most of the 15 examples built were taildraggers, three incorporated tricycle gear—a cutting-edge aircraft development at the time.

In the fuselage, the pilot was accompanied by two other crewmembers. Seated in close proximity was an individual who handled three duties—copilot, navigator, and fire control officer. This multitasking expert was provided with a stowable control column and pedals to help fly the aircraft and was typically the one in charge of aiming and firing the various gyro-stabilized cannons and machine guns bristling from the airplane. In the back, a third crewmember handled radio communications and manned .50-caliber machine guns mounted in side pods to protect the aircraft from aggressors approaching from the rear.

Out in the engine nacelles, the remaining two crewmembers had somewhat simpler tasks. While they had the ability to aim and fire the .30-caliber machine guns in their respective nacelles, their usual duty was simply to reload them. Of somewhat more significant concern was what they would do in the event they had to bail out and fall through the path of the propellers churning the air immediately behind. While various sources refer to explosive bolts intended to jettison the propeller blades prior to bailout, the flight manual only refers to an emergency feathering procedure in which the electric props would feather and stop in six to eight potentially very long seconds.

Almost immediately upon making its first flight in September 1939, it became clear the Airacuda engineers had perhaps bitten off a bit more than they—and the flight crews—could chew. With 1,150 hp Allison V-1710 V-12 engines, the 21,625-pound aircraft could achieve 268 mph in high-speed cruise and reach a service ceiling of 29,900 feet. However, the flight control characteristics and single-engine handling were atrocious and would now be considered far too dangerous to approve for production.

The flight manual made no attempt to hide the unforgiving handling characteristics from pilots, warning that “due to close proximity of propeller to tall surfaces, a sudden reduction of power of one engine either through an engine failure or excessive movement of one throttle will result in a much more violent and immediate control reaction than on multiengine, tractor-type airplanes. Failure of one engine may result in a spin unless the other engine is retarded or trim tab control adjusted immediately.”

It went on to include some concerning limitations: “In case of failure of one engine the other engine should be retarded immediately and the throttle of [the] good engine advanced gradually as trim tab control is adjusted to counteract turning moment. With proper adjustment of [the] trim tab, airplanes can be safely flown on one engine. Single-engine practice flights will not be engaged in below [10,000] feet. This airplane should be flown only by experienced multiengine pilots.”

To provide sufficient electrical power for the various power-hungry systems, such as the targeting gyros, Bell designed the airplane around a 13.5 hp, 2-cylinder, four-cycle piston auxiliary power unit (APU) mounted in its forward belly. It ran at a constant speed of 4,000 rpm and powered the majority of systems, including the aforementioned propellers. Contrary to many reports, the APU was, in fact, not the sole source of electrical power—the right side engine was fitted with a backup generator to provide emergency electrical power to the aircraft in the event the APU failed.

Compounding the challenges of the Airacuda’s unconventional design was insufficient engine cooling. When idling on the ground for extended periods, the aircraft required special fan units with custom ducts that fed into the wing leading-edge intakes to prevent the engines from overheating. This also led to some operational difficulties in flight. 

Ultimately, no further examples of the Airacuda would be manufactured, as the combination of long-range bombers, such as the B-17, and traditional fighter escorts, such as the P-51, proved effective in the war. Two Airacudas were lost in accidents, and unfortunately, all remaining examples were scrapped by 1942.

While the small fleet never directly contributed to the war effort, Bell learned valuable lessons from its design, testing, and production. To keep the engines positioned forward, for example, and thus maintaining a proper center of gravity, each Airacuda engine incorporated a 64-inch driveshaft extension. The vibration and harmonics involved in such an extension are not trivial, and this experience likely helped refine similar extensions utilized in the later P-39 Airacobra and P-63 Kingcobra, both of which were manufactured in the thousands.

The post The Unconventional, Bizarre Bell Airacuda appeared first on FLYING Magazine.

If you’d like to stump everyone at aviation trivia, simply ask them to name the Cessna with the shortest takeoff-and-landing distances. More than likely, guesses would include the O-1 Birddog and possibly the 180 and 182. However, digging into the dustier corners of Cessna’s history reveals the true winner—its one and only helicopter the company ever produced, the CH-1 Skyhook.

The idea of introducing a helicopter to the Cessna product line began to gain traction in the early 1950s. This was a time when the company’s fixed-wing offerings were relatively modest but were on the brink of massive expansion. The lineup in the early part of the decade consisted of the 120/140, 170, 180, 190/195, O-1, and the 310/320 twins but by the following decade would more than double in size and encompass entirely new categories. A helicopter, Cessna thought, would be one more way to gain market share.

Rather than designing a helicopter from the ground up, Cessna went shopping for existing options. Its search eventually took it to the Seibel Helicopter Co., conveniently located on the other side of Wichita, Kansas. In 1952, Cessna acquired Seibel and its S-4B helicopter design, and founder Charles Seibel was retained to lead the engineering team.

The S-4B, while functional, utilized an entirely utilitarian design devoid of any niceties, such as an enclosed fuselage, soundproofing, or a finished interior. Cessna wasted no time replacing the skeletal design with an aluminum monocoque fuselage and cabin that utilized many of the same design principles as its fixed-wing aircraft. Before long, the first CH-1 emerged from the factory and made its first flight in July 1953.

Equipped with its new fuselage that later expanded to incorporate four seats, the CH-1 was sleeker and more modern looking than existing designs, and it was updated beneath the skin, as well. The Siebel’s original 125 hp piston engine was gone and in its place was a far more powerful alternative, ultimately a supercharged 6-cylinder Continental that produced 270 hp. This provided outstanding high-altitude performance, and the CH-1 went on to set several records. In addition to becoming the first helicopter to land on 14,000-foot Pikes Peak in Colorado, it set multiple altitude records by climbing to nearly 30,000 feet.

Cessna’s marketing team pursued both the civilian and military markets, securing a U.S. Army contract for 10 examples that would become known as the YH-41 Seneca. The Army was ultimately unimpressed with the helicopter’s performance, and Cessna bought back six, modifying some systems and converting them to civilian models. 

The company had better luck with the civil model, pursuing the short-range executive market as well as the utility helicopter market. In many respects, the CH-1 was impressive. The cabin was massive, enabling passengers to easily move from one seat to another in flight. At 64 inches wide, it was within 2 inches of a Citation Excel business jet and incorporated 360-degree panoramic visibility.

Unfortunately, the CH-1 was hobbled by several issues that ultimately proved insurmountable. Engine and transmission reliability reportedly was well below par for the market, reflected by the woefully short engine TBO of only 600 hours. This was a fraction of comparable helicopter engines and would have increased hourly operating costs noticeably.

Additionally, the CH-1 was quite expensive to purchase. In 1960, the CH-1C was offered for $79,960. The 1965 pricing for the Bell 47J and Brantley 305 was $67,000 and $54,000, respectively. While Cessna could justify a higher price for the nicer cabin and better high-altitude performance, it perhaps realized it would struggle to make a case against small turbine helicopters that would soon enter the market. Indeed, Hughes priced the 500 at $95,000 nine years later. 

Faced with reliability concerns and diminishing marketability, Cessna ended the CH-1 program and bought back nearly every example for scrapping, presumably to eliminate any product liability concerns. Today, of the 50 examples built, only one survives—a lone YH-41A Seneca in storage and awaiting restoration at the United States Army Aviation Museum at Fort Rucker, Alabama.

The post That Time Cessna Made a Helicopter appeared first on FLYING Magazine.

Historically, some of the most compelling aircraft prototypes have served as launching pads for new and emerging technologies. From clean-sheet engine designs to new aerodynamic concepts to unusual airframe layouts, X-planes from all eras were smorgasbords of cutting-edge engineering. And in the early 1940s, McDonnell combined a multitude of new ideas into its XP-67 in the hopes its performance would eclipse existing interceptors.

A safe, conservative method of introducing a new aircraft design might be to incorporate only a few completely new and unproven concepts at a time. This philosophy enables engineers to isolate the concepts and evaluate them for more widespread use. But in the case of the unique McDonnell XP-67, nicknamed the “Moonbat,” it seems airframe and powerplant engineers alike were given carte blanche to reimagine every component and integrate all the resulting ideas into a single aircraft.

At first glance, the XP-67 has the appearance of an aerodynamic study. With a semi-blended-wing body, a laminar-flow airfoil, and rounded, filleted junctions where different surfaces met, the airframe took on a one-piece, organic appearance. The effort spent on sculpting the airframe in such a manner was motivated by a blistering top speed target of 472 mph—a number McDonnell promised to the military in an effort to win a lucrative production contract.

However unconventional the aerodynamic aspects of the airframe may have been, additional complexities lurked beneath the skin. These came in the form of new and unproven Continental XL-1430 inverted V-12 engines. Liquid-cooled and rated at 1,350 hp each, these engines held much promise when they were developed in the 1930s.

They delivered roughly 1 hp per cubic inch of displacement, making them both smaller and more powerful than the Rolls-Royce Merlins of the same era. Unfortunately, this came at the cost of an inferior power-to-weight ratio. Together with various airframe modifications, the engines contributed to a massive increase in the XP-67’s weight as the development of the aircraft progressed—from an initial target weight of 18,600 pounds to an ultimate weight of more than 25,000.

While weight climbed, aerodynamic challenges emerged. The uniquely sculpted airframe, optimized for efficiency at high speeds, presented severe downsides in other aspects. Despite creative leading-edge intakes to feed cooling air to the radiators, the engines overheated and even caught fire during initial taxi tests and ground run-ups. This was likely attributable to the extremely tight cowlings and ductwork that favored low drag above all else as opposed to fundamental issues with the engines themselves. But it was nevertheless a problem, and when the first flight took place in January 1944, it had to be cut short after several minutes due to overheating in flight.

Engineers quickly revised the engine cooling to address these issues. Less easily solvable, however, were the aerodynamic and handling problems pilots discovered on subsequent test flights. The XP-67 exhibited concerning instability, leading to doubts it would be able to recover from a spin. Additionally, the climb performance fell short of expectations, the approach speed increased from 76 to 93 mph, and the aircraft only ever reached a maximum speed of 405 mph—67 mph lower than the target.

To solve some of these issues, the design team explored alternative engine and propeller options. While the unproven Continental had shown promise and was competitive in the preceding decade, newer developments of the Rolls-Royce Merlin had surpassed its specifications, and jet engines were beginning to emerge as the way forward. The XP-67 and its multitude of concerns appeared to be on borrowed time.

In September 1944, time ran out. During a test flight over St. Louis, an engine caught fire in flight. Although the pilot made a successful emergency landing at Lambert Field (KSTL), the flames spread to the rest of the airframe before emergency equipment could extinguish them, and the aircraft was destroyed. Faced with mounting challenges and a second prototype that was far from completion, the program was canceled and both examples were discarded.

The post McDonnell’s ‘Moonbat’ Definitely Stood Out in the Early 1940s appeared first on FLYING Magazine.

In the mid-1960s, the U.S. Air Force presented aircraft manufacturers with an interesting challenge—design a clean-sheet close air support (CAS) aircraft to replace the aging Douglas A-1 Skyraider. Accustomed to developing sleek fighters and bombers that ventured into supersonic speeds, this new request challenged them to instead prioritize cost, survivability, and low-speed maneuverability. It was a new set of requirements that required new thinking.

Just as the design requirements were unconventional for the time, so too was the appearance of each proposed contender. A total of six manufacturers submitted a wide variety of proposals, ranging from multiengine jets to a single-engine V-tail pusher turboprop. In each case, the manufacturers prioritized function over form, with most concepts utilizing straight wings, bulbous canopies, and a multitude of external hard points on their wings.

The Air Force selected two designs to progress to the final stage, in which the finalists would build flying prototypes. The unconventional-looking Fairchild-Republic A-10 Thunderbolt II, better known as the “Warthog” would ultimately win the contract for this role. But its competitor, the Northrop YA-9A, provided some intriguing design features despite losing the contract.

At a glance, some similarities between the two finalists are evident. Both sport the aforementioned straight wings with many hardpoints, and the external dimensions are nearly identical. Both also utilize twin turbofan engines. But a handful of key differences stand out.

Chief among them, the YA-9A was designed with a high wing, as opposed to the low wing on the A-10. While the specific reasoning for this is unclear, the high wing enables the use of shorter, lighter landing gear. Additionally, a side profile diagram depicts workers standing alongside the aircraft, eye level with the engine, suggesting Northrop touted the design as providing mechanics with easy engine access during maintenance.

The YA-9 also uses a conventional cruciform tail—significantly different from the A-10’s low tail with twin vertical stabilizers. While this design was less complex and presumably lighter than that of the A-10, it provided less redundancy. In practice, A-10s have successfully demonstrated their ability to fly with a single vertical stabilizer.

Like the A-10, the YA-9A utilized turbofan engines, but the engine similarities stopped there. Rather than using a common, simple design like the A-10, the YA-9A was fitted with a less common and more complex geared turbofan called the Lycoming ALF 502. These would ultimately prove less reliable than similar engines, and NASA later salvaged and used them for their QSRA experimental short takeoff and landing jet.

While both contenders employed large Gatling-style rotary cannons buried in their noses, these also differed. While the YA-9A used a six-barrel, 20mm M61 Vulcan, the A-10 used a larger seven-barrel, 30mm General Electric GAU-8/A Avenger. As the latter uses heavier ammunition and the Air Force claimed it has superior ballistics, it would help make the A-10 the more effective combat aircraft.

A deeper dive into the YA-9A’s flight manual reveals additional insight into the overall design. It states that Northrop engineered the aircraft with two primary goals in mind—to provide an extremely stable platform for on-target accuracy during weapons delivery and to provide a high degree of survivability for both aircraft and pilot. The latter was achieved in a similar manner to the A-10, with strategically-located armor.

The on-target accuracy during weapons delivery, however, was achieved through the use of some flight control trickery. Northrop engineers wanted to enable quick steering corrections during weapons targeting, and they wanted to do so without creating any bank or sideslip. Their solution was called SFC, or side force control.

SFC blended the control inputs of the rudder with that of the speed brakes, which, like the A-10, were provided in the form of split ailerons. As the pilot introduces rudder input, simultaneous asymmetric speed brake deployment negates the rudder’s yawing moment. This control and coordination occurred automatically when in SFC mode simply through rudder inputs by the pilot. 

Asked whether such a system would benefit the A-10, an A-10 pilot replied, “I mean…the rudders work just fine.” This underscores the philosophy of simplicity behind the A-10 and suggests complex systems like SFC might have hindered the YA-9A more than they helped.

In terms of flying performance, the YA-9A seemed quite competitive. Takeoff distance at a 2,300-feet pressure altitude (the elevation of Edwards Air Force Base) ranged from 3,800 feet at the maximum takeoff weight of 42,000 pounds down to only 640 feet at 23,000 pounds with full flaps. 

In the air, the YA-9A’s maximum speed was approximately 450 knots. Perhaps more impressive was its ability to maintain single-engine directional control down to only 75 knots. The control effectiveness necessary for this was likely a byproduct of the engineers’ emphasis on low-speed maneuverability in the intended CAS role.

Published landing distances were similarly impressive, with ground rolls ranging from 875 to 1,100 feet. This was helped in part by the massive ground spoilers that deployed to 60 degrees when the system sensed weight on wheels. Among the various performance objectives, this is one in which the YA-9A likely outscored the A-10 during the evaluation.

Ultimately, the A-10 would go on to win the competition, and Fairchild-Republic would go on to manufacture a total of 716 examples between 1972 and 1984. The Air Force mothballed the two YA-9As after the evaluation period but fortunately spared them from the fate of the scrapper. Today, both can be found at museums— one in storage at Edwards Air Force Base awaiting restoration and the other on display at the March Field Air Museum in California.

The post The Close Call of the Northrop YA-9A Prototype appeared first on FLYING Magazine.

Once upon a time, GA aircraft manufacturers pursued market niches with the ferocity of wild dingos. When marketing teams identified a potentially underserved customer segment, they wasted no time introducing minor variations to existing models to accommodate it. Compared to today’s offerings, the resulting variety of aircraft was spectacularly broad and varied.

When Cessna determined some customers would be willing to pay a bit more for a slightly more powerful 172, for example, the company introduced the 175 Skylark. This was little more than a 172 with a different engine, but the company was in pursuit of new market segments and opted to advertise it as an entirely different model.

Similarly, Beechcraft identified markets for both full-sized and smaller light twins in the forms of the Baron and Travel Air. With four seats instead of five or six, thriftier 4-cylinder engines, and significantly lighter weight, the Travel Air was presented as a simpler, more compact solution that emphasized economy rather than outright performance.

Fresh off the successful launch of the unique, twin-boom Skymaster, Cessna began exploring the same opportunity in 1965. Recognizing the market might have room for a smaller, lighter version of the Skymaster, it built a single prototype of the Cessna 327. While it was never given an official name, various sources use the nicknames “Baby Skymaster” and “Mini Skymaster.”

The rationale behind this model was likely rooted in findings shared by other manufacturers—that many owners and operators of twin-engine aircraft travel alone or with only one passenger most of the time. For these customers, it made little sense to haul around excess seats and cabin space while burning additional fuel and paying more to maintain larger, 6-cylinder engines. The diminutive Wing Derringer was an extreme example of minimalist light twins. 

The 327 was Cessna’s solution to this downsizing opportunity. Essentially a 172-sized Skymaster, it was both smaller and lighter than the larger centerline twin. Equipped with two 4-cylinder, 160 hp IO-320 engines, it utilized Cessna’s strutless, cantilever wing, and raked windscreen, similar in design to the 177 Cardinal series. 

The smaller size and sleek lines gave the 327 a sporty look compared with the more utilitarian Skymaster. But like the Skymaster, the front seats were positioned well ahead of the wing’s leading edge. Combined with the lack of wing struts, this would have provided outstanding outward visibility and positioned the 327 to be a favorite for aerial photography.

Cessna never published any dimensions or performance specifications for the 327. Using comparable light twins with the same engines as a reference, we can predict the 327 likely would have had a maximum takeoff weight of 3,500-4,000 pounds, with a maximum cruise speed of 150-175 mph. Fuel burn would also have been correspondingly lower, roughly on par with a Piper Twin Comanche with similar engines.  

First flight took place in December 1967, and Cessna flew the 327 until the following year, logging just less than 40 hours of test flights. At that time, the airplane was presumably placed into storage, and the registration—N3769C—was canceled in February 1972. But unlike many other prototypes, the 327 would serve one last purpose before vanishing forever.

The airplane’s final role would be filled at NASA’s Langley Research Center. There, it was used in the full-scale wind tunnel, or FST, for noise-reduction studies. This research was conducted by Cessna, NASA, and Hamilton Standard in 1975 to evaluate various propeller and propeller shroud designs.

The NASA team removed the front propeller and fitted the 327 with an assortment of three-blade and five-blade options housed within a custom-built shroud. Perhaps surprisingly, the shroud was found to actually increase propeller noise slightly as opposed to reducing it as expected. The airplane was later fitted with Hamilton Standard’s experimental “Q-Fan,” a ducted fan design that was touted to transition from full forward thrust to full reverse thrust in less than one second. 

No official record exists outlining the 327’s ultimate fate. The apparent lack of any information beyond the 1975 wind tunnel testing suggests the airplane was scrapped after that. This was perhaps part of a contractual agreement with Cessna, as the company was known to have discarded other prototypes during that era.

We’re left with a smattering of photos and a few piles of technical reports. Coincidentally, with the introduction of electric vertical takeoff and landing vehicles and a renewed interest in noise-reduction technologies in the GA sector, the studies might prove valuable even today. And for that matter, a compact, efficient piston twin with the safety of centerline thrust might as well.

The post Smaller, Lighter Cessna 327 ‘Mini Skymaster’ appeared first on FLYING Magazine.

For as long as homebuilt aircraft have existed, enthusiasts have enjoyed a wide selection of small, single-seat types from which to choose. From speedy, stub-winged racers like the Cassutt to the Monerai P powered sailplane that weighs less than 300 pounds, variety abounds even among these tiny machines. But in the early 1970s, one exceedingly creative specimen emerged that blended a multiengine configuration with an empty weight of only 440 pounds.

The Aerosport Rail is a tiny, multiengine aircraft and a rather interesting contradiction. On one hand, its designers whittled away at it until every last extraneous element of the aircraft, including a windscreen and enclosed fuselage, was omitted. On the other hand, they introduced complexity and parallel systems by integrating a second engine. 

Browsing through their circa-1970 marketing material, a backstory adds some context. Formed by a magazine editor and aeronautical engineer, the company prioritized safety, ease of assembly, low cost, and fun flying characteristics. And despite the outwardly primitive appearance, the unconventional design lends itself to these qualities.

The T-tail, for example, was chosen to place it out of the prop wash and eliminate buffet, which may have been a concern with a minimalist empennage that was perhaps more likely to bend and flex than other designs. The pusher engine configuration was selected to reduce noise and buffeting around the pilot, and having two engines offered a level of redundancy that made an engine failure a nuisance rather than a catastrophe. And the 2-cylinder, two-stroke, reengineered snowmobile engines were placed close together to minimize any asymmetric thrust resulting from an engine failure.

The designers apparently succeeded in all respects—and in the last one in particular. During initial testing, a pilot reportedly performed a takeoff with the left engine shut down and its propeller windmilling. Additionally, rudder effectiveness was reportedly maintained during single-engine flight all the way down to the 45 mph stall speed.

With both engines operating, performance was spritely. Marketing material promised a takeoff run of 230 feet, with the ability to clear a 50-foot obstacle in 1,230 feet. Cruise speed at 85 percent power and 2,000 feet was said to be 66 mph while burning just under seven gallons per hour total. Top speed was listed as 90 mph, the modest speed number reflecting the substantial parasite drag inherent in the entirely open design. Indeed, at lower speeds such as climbout, the Rail returned decent performance, with the 900 fpm climb rate easily exceeding that of, for example, a Cessna 150.

Considering the 440-pound Rail’s 100-mile range, 220-pound full-fuel payload, and complete lack of any design features related to comfort or ergonomics, this was clearly an airplane optimized for local flights. But for warm summer evenings bimbling around down low over hayfields and picturesque lakes, the peace of mind provided by the unique twin-engine configuration and completely unobstructed visibility would have made for a uniquely enjoyable experience. 

Unfortunately, the Rail was not a commercial success. In addition to the company prototype shown here, FAA records indicate a Rail registered as N44HW was completed in 1976. An article in Sport Aviation mentions it had accumulated more than 14 hours by June of that year, but it was deregistered only four years later. Another Rail, registered as a “Rail II” and wearing the registration N27T, was completed in 1975, but it’s unclear whether it was ever flown.

Whether the lack of success was the result of a technical obstacle not mentioned in Aerosport’s marketing material or whether the Rail simply succumbed to the business challenges that have claimed so many other designs over the years is unclear. Whatever the reason, the aircraft depicted in every photo of the type seems to have disappeared entirely, and its registration was canceled in 1976, six years after its first flight. 

Ultimately, it’s a sad and all-too-common end to an interesting chapter of aircraft design. A floatplane version was in the works, and had that come to fruition, the resulting machine would have amounted to a mini-AirCam, offering similar levels of fun and redundancy at a far lower price. Even comparing landplanes, the Rail, at $2,495 for the complete kit including engines, cost only 20 percent of a new Cessna 150. 

Though the Rail was unconventional to the point of bordering on crazy, and though it was, like many other private aircraft designs, a commercial failure, it looked to offer more fun per dollar than most other types of the era. Perhaps one day it will be resurrected. At the very least, it could enable aspiring professional pilots to build their multiengine time more affordably than ever.

The post The Unconventional, 440-Pound Aerosport Rail appeared first on FLYING Magazine.

In the years following World War II, the economy was booming, Americans were beginning to travel, and aircraft manufacturers were brimming with experienced teams of engineers. With the demand for military aircraft subsiding, virtually all of these companies began exploring new avenues for product development and innovation. It didn’t take Beechcraft long to identify civil aviation as a burgeoning opportunity.

Fresh off the success of the V-tail Bonanza and the larger, 8-to-10 passenger Model 18, Beechcraft management explored the market and noticed a gap in the industry’s product offerings. Prior to the war, types such as the Ford Trimotor, Boeing 247, and Curtiss taildraggers served as the era’s smaller “regional airliners,” but the war effort paused any further development of that segment. Referring to it as a “Feederliner,” Beechcraft reasoned that a small, modernized civil airliner was just what the industry needed.

Dedicating significant engineering and marketing resources to the project, the team got to work. It aimed to position the aircraft as a solution for passenger as well as cargo transport. It opted for a high-wing configuration, an easily convertible cabin layout, and a cargo door in the forward left fuselage, naming the final product the “Twin Quad.”

With a wingspan of 70 feet, a length of 51 feet, and a height of 19 feet, 4 inches, the Beechcraft 34 Twin Quad was a sizable machine. Ironically, each dimension is nearly identical—within 1 to 4 feet—to the Cessna SkyCourier, the latest offering from Beechcraft’s successor. Even the maximum takeoff weight of 19,500 pounds is within 500 pounds of the modern twin turboprop.

The team decided to incorporate a V-tail into the design, first installing it on an existing AT-10 Wichita twin for testing purposes. This enabled them to evaluate the tail’s effectiveness at providing directional control on a multi-engine aircraft of similar size and weight to the Twin Quad before finalizing and freezing the design.

It’s possible the V-tail was pursued primarily because of the technical advantages it was thought to provide. It’s also possible it offered more value to the marketing department as an instantly identifiable branding feature that visually differentiated it from the competition. Whatever the driving reason, Beechcraft ultimately incorporated the V-tail into the final design.

Though the V-tail was the most notable design feature of the aircraft from a visual standpoint, it paled in comparison to the originality and uniqueness of the engine layout. 

In an effort to harness the maximum power in the smallest, most aerodynamic packaging possible, the team opted to utilize four 375 hp Lycoming GSO-580 flat-8 piston engines and buried them entirely within the wing. The engines were configured in pairs, with each coupled together and driving a single propeller via clutches and a gearbox. The clutches were designed so that engine torque compressed and engaged the clutch discs. 

In the event of an engine failure, the failed engine would automatically disengage from the gearbox, and the remaining engine would continue to drive the propeller. This feature was presented as a safety improvement—although the loss of one engine would result in a power reduction, it would present no corresponding asymmetric control issues.  

The Twin Quad used two massive full-feathering, two-blade propellers for propulsion, and naturally, they were driven through reduction gearing. At 11 feet long, if the engines were to turn them directly at a normal cruise rpm, the propeller tip speeds would have exceeded Mach 1.5. The reduction gearing provided a ratio of 40:21, or roughly 2:1, bringing the propeller rpm range down to a quiet and comfortable 1,500 rpm in cruise flight.

During engine shutdown, the engine clutches would disengage entirely. A note in the operating manual advises that if high-velocity wind rotates the propellers after shutdown, the clutches may be reengaged to lock them into position. Presumably, standard operations would call for the clutches to be engaged regardless, as the sight of rotating propellers on a vacant, parked aircraft would naturally create concern for any observers on the ramp.

Because the Twin Quad was designed for airline operations, it was equipped with full anti-icing capability. Two combustion heaters—one for the wing, and one for the tail—provided heat for the leading edges that was distributed along the insides of the leading-edge skins. The propellers were electrically deiced, and the cabin heater ducted hot air into the space between the two panes of glass that made up each cockpit windscreen.

The Twin Quad made its first flight in autumn 1947. Shortly thereafter, the marketing team stopped using the term “Feederliner” to describe the aircraft, instead switching to “Beechcraft Transport.” This indicated a change in marketing strategy to emphasize non-airline operations, which likely included executive transport. 

Detailed cruise performance wasn’t provided in the preliminary flight manual, but VNE is listed as 270 mph and VNO as 220 mph. Minimum takeoff climb speed is listed as 96 mph, and the bottom of the white arc is 75 mph. 

Given the total horsepower available, the Twin Quad’s engine-out takeoff performance seems fairly decent. In the event of an engine failure after V1 at the maximum weight of 19,500 pounds, the charts indicate it will clear a 50-foot obstacle in just below 3,500 feet at sea level. By comparison, the modern Cessna SkyCourier requires 2,740 feet at roughly the same weight with both engines operating and twice as much power available. Landing distance over a 50-foot obstacle is listed as 2,000 feet at sea level and maximum weight.

The charts optimistically include separate listings showing performance with 40-mph headwinds. It is unclear whether this is a function of an overly optimistic marketing team or simply reflected the reality of everyday weather conditions in Wichita, Kansas. 

Range figures aren’t provided, but endurance can be calculated with the available data. Given the Twin Quad’s total fuel capacity of 536 gallons and the fuel consumption figures of 130 total gallons per hour at maximum continuous power and 80 total gallons per hour at 75 percent power, the resulting endurance would have been 4.1 to 6.7 hours.

Tragedy struck during a certification test flight in Wichita on January 7, 1949. Just after liftoff, an electrical fire occurred. While attempting to extinguish it, a crew member reportedly turned off an “emergency master switch” that resulted in both engines shutting down. The aircraft then stalled and went down, killing one of the pilots.

Following the incident, Beechcraft terminated the program entirely. No specific reason was provided, but it’s possible the decision was driven in part because of a lukewarm response from the market. Ultimately and unfortunately, what remained of the Twin Quad was scrapped.

Today, all that remains is a small handful of photos and scraps of documentation. And while the large Bristol Brabazon airliner flew with a nearly identical engine/propeller arrangement later that year, it would ultimately succumb to the same fate—canceled, scrapped, and relegated to the dusty shelves of aviation history.

The post Beechcraft Twin Quad: A ‘Feederliner’ That Almost Was appeared first on FLYING Magazine.