With innovations in sustainable fuels, airframe design, and safety, we may not recognize the machines that take us into the skies 20 years from now. Incredible resources are being poured into development of new technology at a rate not seen in 80 years—at least in the private sector. What’s surprising and inspiring is that much of the innovation shaping aviation across the board comes from the ground up—from general aviation—rather than trickling down from the airlines and military.

Pipistrel, one of these key ground-up innovators, experienced humble beginnings as a tiny hang glider manufacturer a few decades ago. It grew gradually and strategically from its original home in a garage serving hobbyists to winning consecutive competitions for flight design at NASA—and eventually scoring a $1.3 million grant from the agency 11 years ago.

Now, it’s part of Textron eAviation, and two years in, the company marked significant expansion in Africa, Canada, and the United States—including a deal with the U.S. Air Force—and a historic first piloted flight of liquid hydrogen powered electric aircraft. All of this innovation is impressive, and talking about it in sweeping terms rather overstates the obvious at this point.

• READ MORE: And Just Like That, Pipistrel is a Textron Property

But what does it mean for pilots—particularly those of us who inhabit the GA sphere? How will the advancements of companies like Pipistrel shape the practical realities of flying?

“It’s, to me, incredibly rewarding that now, some 15, almost 16, years after we started flying electrically, there’s genuine interest in the public domain for this field,” Tine Tomažič, Pipistrel’s director of engineering and programs, tells Plane & Pilot. “It’s interesting how people call it an ‘emerging field.’ To me, it seems like [we’ve been] doing it forever. 2007 was when we put together our first battery that flew. Looking back, it’s not something I would ever be willing to put in the hands of a customer, but it worked.”

The company has gone through generations of battery technology, applied to various airframe projects, since then.

“We’re probably still the one entity that has tried in flight tests, and put through to the product stage, more different electric aircraft than anyone else,” Tomažič says. “We’ve had gliders, trainers, record-setting aircraft, and even some hybrids involved in hydrogen flight through partnerships. So we’ve seen a lot.”

The Taurus Electro, a self-launching glider and the company’s first deployment airframe of choice in 2007, now flies with what Tomažič terms its third generation of battery performance and fourth generation of battery functionality. The liquid-cooled Velis Electro and its predecessor, the air-cooled Alpha, are also on their third generation of batteries. Timing and economics factor into when it’s feasible to introduce new technology waves, and Pipistrel was as affected by the COVID-19 pandemic as the rest of the industry.

“Pipistrel is continuously screening what’s happening on the battery technology front,” says Tomažič. “Through the years, we’ve equipped our laboratories, and we’ve essentially self-developed methodologies that allow us to screen what’s going on in the battery industry. We obtain samples of actual batteries from the makers and put them through their paces.”

Engineers then assess the electrical performance to answer questions such as whether a particular technology could improve the endurance of the Velis or affect the climb speed of the Taurus. They also consider the longevity of the battery, which is an economic driver.

• READ MORE: Pipistrel’s Velis Electro Promises Electric Revolution

“We look at the safety and the thermal aspects,” Tomažič says. “All of these are being assessed for essentially every new sample we can get our hands on. This catalog of cells is ever-growing. I think we are past 80 different cells in our catalogs. And we know all about how they would behave in terms of performance, safety, and longevity.

“That’s actually key because there’s no such thing as one single battery technology to find in a glider application or a motor plane application, let alone a hybrid powertrain… It is the battery that gives the aircraft its character.”

Function Drives Form

Airframe design, and aircraft purpose and mission, are inseparable from the technology that drives them. The necessary tradeoffs in battery technology development give new life to the old Bauhaus principle “form follows function.”

Pipistrel uses different battery chemistries for its products depending on the capabilities of each technology. Tomažič draws an analogy with sports to illustrate why one battery is not one-size-fits-all. You wouldn’t send a sprinter to run a marathon—or the other way around.

“There are nuances to that,” he says, “but you have to choose the best tool for the job. And when it comes to electric flight…what’s always hidden and perhaps not that easy to understand by an observer is how much the character of the aircraft can actually change because of what the battery can or cannot do.”

Tomažič points to a common misconception that you can produce viable electric flight products by swapping the powertrain, going from a fuel-powered airplane to an electric one for example. Some characteristics of electric drives make existing aircraft less than ideal for deploying electric platforms.

“Just like you may have seen with early electric cars where this exact thing was happening, they pulled out the big [engine] block and put in the battery and, I mean, how far did they drive? Yuck,” he says. “Now you see designs that were born to be electric, and they don’t have the feasibility of ever putting in a gasoline engine, and that makes the product really shine. I think the successful products will be those that are being prepared, or were prepared, with electrification in mind—or being developed only so that they are electric.

“We made an intentional choice with ourselves that we will just not design new aircraft if they are not at least hybrid-electric or all-electric, because we can appreciate how powerful the connection between the aircraft’s airframe and powertrain actually is. It’s a real marriage.”

This translates into tradeoffs in functionality, depending on what purpose comes to the fore.

• READ MORE: The Value of a Light, Simple Aircraft

“If you have a draggy airframe, it doesn’t matter if you have a super-efficient electric motor on the other side,” he says. “Everything somehow has to come in balance, and that’s what creates goodness. And this means that good electric aircraft will undoubtedly look and feel a little bit different from what you are used to seeing on your classic [Cessna] 172, your Piper, your Diamond, your Cirrus, etc. There is change coming because of electrification on the airframe look and feel side of things as well.”

Endurance, Cost, Efficiency

One of those tradeoffs might be a more efficient, cost-effective battery charging cycle at the expense of range and endurance. Or the converse—better range might mean increased cost per flight hour and reduced efficiency. These options might look different depending on whether an aircraft is intended as a trainer or for GA cross-country missions in the U.S.

“Let’s say I want to improve charging speed. Maybe I will sacrifice a bit of cycle life,” says Tomažič. “For this reason, we are screening so many different battery technology candidates, so we can make an informed decision about where we will be introducing, let’s say, the increase of goodness, and Velis Electro is a good example. Between generations one and two of the batteries, what improved was the longevity, more cycles essentially obtained from the same battery, meaning every flight hour becomes significantly cheaper, and there is the opportunity to charge the battery faster—but the flight times are about the same.”

The next generation of battery might mean an increase in flight time, or it could mean further improving efficiency and cost.
“It’s all about how you strategically approach these things,” he says. “Every aviation maker, no matter large or small, continues to dream along the lines of faster, farther, bigger, more. We are not different.”

The endurance capabilities reflected in the Pipistrel aircraft are not at the leading edge of battery technologies, but instead are the best mix of affordability, safety, and practicality for the design, Tomažič points out.

The Velis Electro, designed to be operated alongside training aircraft that flight schools may already have, was not meant to replace a fleet and provide a platform that would fit an entire syllabus. Instead, Pipistrel designed it primarily as a cost-effective option for traffic pattern training with a low noise footprint.

“It is fantastic to see that people started asking questions like, ‘When can we fly longer?’ because this means that they started trusting the product as is,” says Tomažič. “We don’t get questions like, ‘When can we improve the reliability on this and that?’ or ‘This doesn’t work, or that doesn’t.’ It all works. The problematic child is endurance.

“I think range anxiety is a real thing when it comes to electric mobility: cars, electric bikes, scooters. Airplanes are no different, and I can appreciate this mindset. If you look at what the absolute majority of general aviation is doing, it kind of revolves around the three-hour mark, and that’s kind of sized according to what human bladders can take.”

Tomažič hints that a three-hour electric aircraft is possible in the future, “and if any company can do it, I want it to be us because we can leverage all that we’ve learned and build on top of these solutions…in a way that people will accept—and they will accept it when it’s quiet, practical, simple, and cheap.”

Range and endurance increase as technology advances, and Tomažič wonders if potential complications that come with new technologies will be acceptable to GA pilots. He points to the “modest but incredibly rewarding” truism of Pipistrel’s Taurus Electro and Velis Electro: Their environments are familiar for pilots.

“The technology has reached levels of maturity where you don’t have to be an engineer or an astronaut or some local neighborhood weirdo with funky hair because of having been electrocuted,” he says. “Electric aircraft fly just like everything else.”

Upgrades and Future Compatibilty

Prudent or thrifty aviators may wonder if they could end up throwing away money on an aircraft that could become obsolete in a relatively short time. Our legacy aircraft have proven their reliability and staying power. What about these new birds?

Pipistrel designs its electric planes to be upgradeable over time, hoping to continue to lead the industry by ensuring new battery generations are compatible with its existing airframes, in addition to developing new platforms. And these upgrades don’t entirely correspond to engine upgrades and overhauls.

Tomažič asks the conventional aircraft owner to consider how often a craft becomes better in its lifetime.

“Pretty much never, right? Unless you throw a lot of financials on it,” he says. “Changing the avionics is kind of like the favorite cosmetic surgery of choice on a typical plane. But it doesn’t change its endurance. It doesn’t change its payload. It doesn’t change its performance. And with electric flight, all of these parameters continue to improve.

“The newest research we are applying to batteries goes in two directions, or almost two and a half directions. One of them is the more modest continuation of what we call wet energy chemistries, [or improvements in lithium-ion technologies].”

And then there are solid-state batteries, an emerging technology that replaces the liquid electrolyte insulation with a powder-like substance.

“That makes the aircraft’s battery potentially behave differently, and maybe safer as well,” he says. “But, in particular, it gives different packaging options to the battery. Now, batteries are…kind of luggage, in the sense of how they fly.”

He says Pipistrel is working on ways to better integrate batteries into airframes, exploring the possibilities of putting them into wing structures instead of the fuselage to offset the problem of bulk. Solid-state batteries are one potential solution.

“The most exotic battery research happens on what we call structural batteries,” Tomažič says. “Essentially [this means] putting batteries inside composite laminates so that the structure of the plane starts to get a dual function. Initial applications will not be for, let’s say, achieving propulsion, but the aircraft has many different electrical needs, including avionics.”

Pipistrel’s engineers are asking, what if there’s a better way to package batteries than as luggage? These new ideas take time to mature. For battery technology fielding, Tomažič asserts that there’s no such thing as year-over-year growth. A battery cell maker decides to start manufacturing a new chemistry, but with the decision-making time and production taken into account, it can be 40 years before particular batteries become cost-effective.

“There’s no such thing as me calling up to a supplier and saying, ‘Hey, can I get a 6 percent battery next year?’” he says. “The answer is probably not, but in three years’ time, we will have a new factory run on a new chemistry, and then the jump will be more noticeable.”

Tomažič suggests we can expect generational upgrades every three to five years or so.

“And this is what we’ve been achieving historically very successfully,” he says. “There will be a battery generational upgrade, anywhere between 10 and 30 percent improvement on a parameter that we choose. This might be endurance; it might be speed of charging; it might be longevity, like the reduction of the operational cost per hour. There’s no such thing as improving 30 percent across the board because all of these measurable battery parameters manifest themselves as different chemistry or different use of materials or different packaging. So there’s no free lunch.”

MOSAIC and Beyond

The potential changes on the horizon with the MOSAIC notice of proposed rulemaking may open doors for Pipistrel in terms of accessibility to more pilots in the U.S. Tomažič, who contributed to general aviation and light sport standards through ASTM as a company representative, believes MOSAIC will offer opportunities for pilots across a wide demographic—and open up those for OEMs and others in the industry.

“It is an enabler of electrification in the U.S., absolutely, so we are looking forward to our existing products like Velis Electro and Taurus Electro, which don’t meet the definition of what is a light sport aircraft today,” he says. “[But they] will be enabled in the U.S. skies sooner rather than later. We are all paying attention to when this rule actually is implemented, and we are working hand in hand with the FAA to…start implementing [these] aircraft into the field.”

• READ MORE: My Take on MOSAIC, as Our Comment Window Closed

So what technologies like those being developed by Pipistrel will offer a solution to GA pilots in the U.S.? Tomažič suggests aviators approach this with an open mind. You might find there’s more to like than you think.

While he acknowledges that there are many ways to draw comparisons between electric power, turbines, and normally aspirated gas-driven engines, Pipistrel’s certification status points to the fact that the technology, and electric flight in general, is mature today.

“It’s not only lower noise and less costly operation,” he says. “There is a significant opportunity to lower the cost of a typical flight hour by half just by introducing electric flight. But this comes at the expense of revisiting how we look at flying in particular from the lens of the aircraft size and its endurance in flight.”

Four-seat aircraft often carry only two persons aboard, and aircraft capable of longer endurance may be out for only an hour or two during training missions: arguably a waste of resources. For now at least, electric aircraft options are necessarily more specialized in their mission capabilities.

“Pilots will have to come to an understanding that there will be a bigger variety of tools,” Tomažič says. “But the good news is that these tools will continue to improve, so I think an electric aircraft will become a way better investment than ever before, because every time a new battery comes up, you’ll have an aircraft that’s better than ever before. And this is a direct opposite of what’s typically happening once you acquire an expensive asset.”

The technology interface available to the pilot provides real-time information that can improve flight planning and safety in all phases. The resulting simplicity reduces distractions. In a typical flight, “you have to create a mental picture that assembles fuel pressures, oil pressures, some temperatures, and you kind of say, oh, it looks all right,” Tomažič says. “An electric propulsion system with a display will just tell you this every split second. You don’t have to wonder. You have it right there in front of you.”

Mechanics can receive a wealth of information at a glance, or the touch of a button, as well. Operators and maintenance pros can access Pipistrel aircraft maintenance data and aircraft logs, and they don’t need specialized equipment—just a USB key and access to the website.

“They upload the data log, same as an attachment to an email, and the whole situation is portrayed to them,” Tomažič says. “Imagine a flight school that can revisit the complete behavior of the aircraft since its inception and look for exceedances or whether the students and instructors were using the aircraft in full accordance [with] how it should be used. If something happened, you have it right there…much less is hidden.

“For us, what matters a lot is that people understand the technology that they’re using and that they find it likable.”

Moving to Sustainability and Safety

You can’t ignore the pressures on the aviation industry to move toward decarbonization and sustainability. That leads Tomažič to wonder: Which aircraft will be the best pilot-makers or zero-emission passenger airliners of the future?

“It’s probably not the old-school trainers,” he says. “It’s probably something that is more in line technologically with the future transport needs. And this may be air taxis, or this may be the next zero-emission airliner. … It’s not coming overnight, but pilot education also doesn’t happen overnight. So MOSAIC to me is an enabler of better pilots that are better suited for the challenges of tomorrow once these technologies make it all the way up into the airline world.”

Accident statistics show a depressing tendency for human factors to be at the heart of crashes: a pilot misreading a situation, getting confused, or some combination of forces converging at once to produce an ultimately wrong decision.

“The level of transparency that is catered by electric flight is kind of like using your mobile phone,” Tomažič says. “You know exactly how full your battery is. You can make decisions to stop using your TikTok [app] so that you preserve the battery for the important phone call at the end of the day. But you can do that because you know exactly where you stand.”

Pipistrel’s battery management systems (BMS)—sometimes referred to as hybrid management systems by the company to differentiate its technology from a more generic system that can enable and disable battery functionality—provide similar transparency and functionality in the air. The user interface goes beyond simple battery charge indications.

“What our systems are able to do is actually forecast what is happening with the battery and give clues into how much longer you can continue to use the battery before maintenance,” Tomažič says. “[The] Velis Electro, which has the same kind of a BMS system as the Taurus Electro…has a progress bar that goes from 100 percent when new to zero when it’s time to replace the battery. And this doesn’t mean zero, end-of-life criteria—it’s kind of like the TBO for the engine.

“Imagine a way that you would be able to forecast how your engine will perform based on compression of the pistons. Sometimes you do that as part of a yearly checkup. Our systems do this every single time you power them up…because they monitor every single thing that the battery is doing when it’s flying or charging. And because of our catalog of battery behavior…our battery management systems essentially contain the model of the anticipated behavior for every battery.”

If something is off, the system can flag it for the pilot. The information is provided visually and continuously during a given flight. Menu options allow for granular information to alert an owner to issues or aid in preflight planning. While you can visually inspect levels of the fuel tanks in an avgas-driven aircraft before flight, a battery looks the same and feels the same regardless of charge. So this kind of interface is vital.

Pipistrel, from glider to electric airplane, has worked to create affordable solutions for this and other elements. “You see it in our electric flight, cargo drone project, and many other places,” says Tomažič. “And Textron eAviation is able to propel this ideology through very fast-paced innovation because they are able to add resources that Pipistrel never had access to. I think we can all be very excited about the next [few] years, including gliders… As I said, I want to be the company that delivers the all-can-do, all-electric airplane in the future, because we can see how that is possible.

“I think we are at the moment in time where it’s a matter of ‘when,’ not a matter of ‘if.’”

Editor’s note: This story originally appeared in the Jan/Feb 2024 issue of Plane & Pilot magazine. 

The post Electric Atmosphere appeared first on Plane & Pilot Magazine.

Read about the Cessna 120 and 140 in detail here.

Equipped with a smooth and quiet 85 hp Continental C85 that sips fuel at a rate of roughly 4.5-5 gallons per hour in cruise, operating costs are minimized. Only 176 hours have been logged since the last major overhaul. Additionally, this example has had its fabric wing converted to metal covering. At the expense of some additional weight, the result is a wing that no longer requires fabric inspection or a costly $10,000-plus fabric replacement. Robust spring-steel landing gear rounds out operating economy, with no bungee cords or shock absorbers to maintain or replace.

• READ MORE: Incredible Plane: Cessna 150

This example comes with a clean panel, shoulder harnesses, wingtip strobe lights, matching wheel pants, and timeless paint scheme. 

Pilots interested in a classic taildragger that’s as easy to fly as it is to own and maintain should consider this 1946 Cessna 120, which is available for $39,500 on AircraftForSale.

You can arrange financing of the aircraft through FLYING Finance. For more information, email info@flyingfinance.com.

Each day, the team at Aircraft For Sale picks an airplane that catches our attention because it is unique, represents a good deal, or has other interesting qualities. You can read Aircraft For Sale: Today’s Top Pick at FLYINGMag.com daily.

The post Bargain Buys on Aircraft For Sale: 1946 Cessna 120 appeared first on Plane & Pilot Magazine.

With an airframe total time of 4,450 hours, this aircraft has proven its resilience in the skies. Its Continental 0300D engine, paired with a McCauley borer prop, ensures reliability and performance for your missions. 

Equipped for exploration, the Cessna 170B comes fitted with a range of navigation equipment, including a KLN 90B, VOR, ILS, DME, 2VHF, KT70 Mode C, Garmin 196, and a 406 ELT. The communication setup features a KX 155, ensuring reliable contact during your flights.

• READ MORE: Cessna 170A: Rebuild Of A Lifetime, Literally

Step into a comfortable interior, upgraded in 2015, offering front shoulder harnesses, a folding rear bench, and an extended baggage area for added convenience. The polished aluminum exterior with highlights adds a touch of elegance to this aviation classic.

As a tailwheel predecessor to the iconic Cessna 172, the Cessna 170 played a pivotal role in aviation history. Despite initial hesitations, Cessna’s decision to explore the modification of the 170 led to the birth of the immensely popular Cessna 172, revolutionizing general aviation. Now, for $85,000, you can own a piece of this historical journey and experience the joy of flying in a true aviator’s delight.

Explore the skies with the Cessna 170B, where history meets the thrill of flight.

Interested in more deals like this? Check out AircraftForSale.com and our new PlanePrice feature that gives you a window into the opportunities that are out there.

The post Bargain Buys on AircraftForSale: 1952 Cessna 170B appeared first on Plane & Pilot Magazine.

Like so many others, my journey toward a career in aviation began in the left seat of a shiny, polished, aluminum-and-red 1959 Cessna 150. N5709E was the prize possession of the Virginia Tech aviation department and carried me and my friends on our first flights, first solos, and private pilot check rides, and then on to a career in military or commercial aviation. We were not alone. The Cessna 150 taught the post-1950s world to fly. So, how did this remarkable little airplane come to be such a success?

Those pilots who subscribe to the axiom “never fly the A model of anything” will be pleased to know the first model of this small but sturdy aircraft was simply the Cessna 150. Spanning the 1959 and 1960 model years, the original was an extensive update of the successful Cessna 120/140 line. Cessna 140 production had ended in 1951 as the postwar aviation boom flagged. However, by the end of the decade, the training market was beginning to heat up, and Cessna decided to get into the game.

The Cessna 150 prototype squared off the wingtips and tail surfaces of the 140, featured a straight, windowless tail cone, manual 40-degree Fowler flaps, and most important for the training market, tricycle landing gear. The systems were simple and even a bit rudimentary. The stout little Continental O-200A, 100 hp four-banger was started by pulling on a shiny “T” handle at the top of the minimal instrument panel. The handle tugged a cable that engaged the starter. Venturis powered the basic vacuum system, and the generator was driven directly off the accessory drive, eliminating the need for a drive belt.

Of the first Cessna 150 model, 683 were produced in 1959 to ’60, and they are, by most accounts, the lightest, fastest and, many will say, most fun to fly. Three models were offered—the standard, trainer, and intercity commuter. The latter added luxuries such as a vacuum pump, attitude indicator, and rotating beacon. The major shortfall of the tiny Cessna was its narrow cabin. Advertisements of the time usually featured what appeared to be 7/8-scale pilots and passengers sitting happily side by side with their luggage neatly behind the seats. In reality, two standard FAA 170-pound occupants would find the cockpit a bit cramped, and extensive crew coordination was often required for simple acts such as putting on a jacket.

However, none of this really matters because the Cessna 150 remains to this day a delight to fly. It cruises at 90 mph (78 knots), stalls at 47 mph (41 knots), and the manually actuated, 40-degree flaps allow for very precise short-field performance. Its 22.5-gallon fuel tanks and 6-gallon-per-hour fuel consumption allow for a realistic no-reserve range near 300 nm. Control forces are light and visibility is good, as long as a wing is lifted before each turn, and the spring steel “Land-O-Matic” main landing gear forgives the wide variety of student pilot landings. To top it off, the secret to the longevity of the Cessna 150 was its ability to be upgraded, modernized, and adapted to the needs of newer generations of pilots.

The Cessna 150A, introduced in 1961, increased the size of the rear side windows and moved the main landing gear legs rearward by 2 inches. This counteracted the original’s disturbing habit of settling on its tail.

The next big upgrade occurred in 1964. The Cessna 150D model introduced the ubiquitous “Omni-Vision” rear window. Both the 1964 D model and 1965 E model combined the manually activated 40-degree flaps and the straight vertical tail from the earlier models, making them a favorite of the National Intercollegiate Flight Association’s (NIFA) annual precision landing competition. By 1965, the F Model introduced a 35-degree swept vertical tail, electric flaps, and a list of aerodynamic improvements, including a standard spinner in all models.

One of the most welcome additions arrived in 1967 with the 150G model’s curved entry doors, which provided an additional 3 inches of cabin width. Not to be outdone, the 1970 model heralded the introduction of the Cessna 150K Aerobat. The Aerobat—with its six positive and three negative G limits, shoulder harnesses, distinctive checkerboard paint, and dual skylights—was an instant hit. Still powered by the 100 hp Continental O-200A, the Aerobat is no Pitts Special or Extra 300, but it provides a great platform for basic aerobatic training, and spin and upset recovery, as well as energy management training.

The Cessna 150 proved to be an international success too. Nearly 2,000 Cessna 150 models were constructed in Reims, France. While these aircraft usually mirrored their stateside models, many featured the Rolls-Royce-built Continental O-240 variant that increased horsepower by 30 percent.

The Cessna 150 enjoys many aftermarket modifications to the Cessna 150. At least two supplemental type certificates (STCs) allow for the installation of the Lycoming O-320 or O-360 in place of the original Continental. This mod increases fuel consumption and reduces range significantly, but it dramatically increases performance at high and hot airports. And in a return to its Cessna 120/140 roots, the “Texas Taildragger” conversion puts the Cessna 150 back on conventional gear, providing the added benefit of reduced drag and weight associated with the removal of the nose landing gear.

By 1977, the final year of Cessna 150 production, the reduced availability of 80 octane fuel and a nearly 150-pound empty weight increase over the original Cessna 150 necessitated a change to the Lycoming O-235. Designated the Cessna 152, power increased modestly to 108 hp and, because of concerns about full-flap go-arounds, the electric flaps were limited to 30 degrees. Approximately 7,500 Cessna 152s were produced in the U.S. and France during its 10-year production run that ended in 1988.

When production halted, the company had built 31,471 Cessna 150/152s, placing the 150 in fifth on the list of most produced aircraft, just behind the entire Piper PA-28 line and just ahead of the Cessna 182. As to that original question—“Why not just restart the production line?”—you will have to ask Cessna. It may be increased production costs, an effort to avoid clashing with its incredibly successful Cessna 172 (the most produced airplane in the world), or competition from the growing LSA market, just to name a few. In any event, the Cessna 150 stands out as the definitive two-seat trainer of its time with nearly 23,000 registered around the world.

Oh, and how about N5709E? Lovingly restored to its 1959 livery, it is still on the active rolls and can be seen flying to various events where classics are appreciated. So, next time you talk to your pilot friends, ask them about their first airplane. You might be surprised how many got their start in the sturdy Cessna 150. 

Editor’s Note: This story originally appeared in the September 2023 issue of Plane & Pilot magazine. 

The post Incredible Plane: Cessna 150 appeared first on Plane & Pilot Magazine.

Like so many others, my journey toward a career in aviation began in the left seat of a shiny, polished, aluminum-and-red 1959 Cessna 150. N5709E was the prize possession of the Virginia Tech aviation department and carried me and my friends on our first flights, first solos, and private pilot check rides, and then on to a career in military or commercial aviation. We were not alone. The Cessna 150 taught the post-1950s world to fly. So, how did this remarkable little airplane come to be such a success?

Those pilots who subscribe to the axiom “never fly the A model of anything” will be pleased to know the first model of this small but sturdy aircraft was simply the Cessna 150. Spanning the 1959 and 1960 model years, the original was an extensive update of the successful Cessna 120/140 line. Cessna 140 production had ended in 1951 as the postwar aviation boom flagged. However, by the end of the decade, the training market was beginning to heat up, and Cessna decided to get into the game.

The Cessna 150 prototype squared off the wingtips and tail surfaces of the 140, featured a straight, windowless tail cone, manual 40-degree Fowler flaps, and most important for the training market, tricycle landing gear. The systems were simple and even a bit rudimentary. The stout little Continental O-200A, 100 hp four-banger was started by pulling on a shiny “T” handle at the top of the minimal instrument panel. The handle tugged a cable that engaged the starter. Venturis powered the basic vacuum system, and the generator was driven directly off the accessory drive, eliminating the need for a drive belt.

Of the first Cessna 150 model, 683 were produced in 1959 to ’60, and they are, by most accounts, the lightest, fastest and, many will say, most fun to fly. Three models were offered—the standard, trainer, and intercity commuter. The latter added luxuries such as a vacuum pump, attitude indicator, and rotating beacon. The major shortfall of the tiny Cessna was its narrow cabin. Advertisements of the time usually featured what appeared to be 7/8-scale pilots and passengers sitting happily side by side with their luggage neatly behind the seats. In reality, two standard FAA 170-pound occupants would find the cockpit a bit cramped, and extensive crew coordination was often required for simple acts such as putting on a jacket.

However, none of this really matters because the Cessna 150 remains to this day a delight to fly. It cruises at 90 mph (78 knots), stalls at 47 mph (41 knots), and the manually actuated, 40-degree flaps allow for very precise short-field performance. Its 22.5-gallon fuel tanks and 6-gallon-per-hour fuel consumption allow for a realistic no-reserve range near 300 nm. Control forces are light and visibility is good, as long as a wing is lifted before each turn, and the spring steel “Land-O-Matic” main landing gear forgives the wide variety of student pilot landings. To top it off, the secret to the longevity of the Cessna 150 was its ability to be upgraded, modernized, and adapted to the needs of newer generations of pilots.

The Cessna 150A, introduced in 1961, increased the size of the rear side windows and moved the main landing gear legs rearward by 2 inches. This counteracted the original’s disturbing habit of settling on its tail.

The next big upgrade occurred in 1964. The Cessna 150D model introduced the ubiquitous “Omni-Vision” rear window. Both the 1964 D model and 1965 E model combined the manually activated 40-degree flaps and the straight vertical tail from the earlier models, making them a favorite of the National Intercollegiate Flight Association’s (NIFA) annual precision landing competition. By 1965, the F Model introduced a 35-degree swept vertical tail, electric flaps, and a list of aerodynamic improvements, including a standard spinner in all models.

One of the most welcome additions arrived in 1967 with the 150G model’s curved entry doors, which provided an additional 3 inches of cabin width. Not to be outdone, the 1970 model heralded the introduction of the Cessna 150K Aerobat. The Aerobat—with its six positive and three negative G limits, shoulder harnesses, distinctive checkerboard paint, and dual skylights—was an instant hit. Still powered by the 100 hp Continental O-200A, the Aerobat is no Pitts Special or Extra 300, but it provides a great platform for basic aerobatic training, and spin and upset recovery, as well as energy management training.

The Cessna 150 proved to be an international success too. Nearly 2,000 Cessna 150 models were constructed in Reims, France. While these aircraft usually mirrored their stateside models, many featured the Rolls-Royce-built Continental O-240 variant that increased horsepower by 30 percent.

The Cessna 150 enjoys many aftermarket modifications to the Cessna 150. At least two supplemental type certificates (STCs) allow for the installation of the Lycoming O-320 or O-360 in place of the original Continental. This mod increases fuel consumption and reduces range significantly, but it dramatically increases performance at high and hot airports. And in a return to its Cessna 120/140 roots, the “Texas Taildragger” conversion puts the Cessna 150 back on conventional gear, providing the added benefit of reduced drag and weight associated with the removal of the nose landing gear.

By 1977, the final year of Cessna 150 production, the reduced availability of 80 octane fuel and a nearly 150-pound empty weight increase over the original Cessna 150 necessitated a change to the Lycoming O-235. Designated the Cessna 152, power increased modestly to 108 hp and, because of concerns about full-flap go-arounds, the electric flaps were limited to 30 degrees. Approximately 7,500 Cessna 152s were produced in the U.S. and France during its 10-year production run that ended in 1988.

When production halted, the company had built 31,471 Cessna 150/152s, placing the 150 in fifth on the list of most produced aircraft, just behind the entire Piper PA-28 line and just ahead of the Cessna 182. As to that original question—“Why not just restart the production line?”—you will have to ask Cessna. It may be increased production costs, an effort to avoid clashing with its incredibly successful Cessna 172 (the most produced airplane in the world), or competition from the growing LSA market, just to name a few. In any event, the Cessna 150 stands out as the definitive two-seat trainer of its time with nearly 23,000 registered around the world.

Oh, and how about N5709E? Lovingly restored to its 1959 livery, it is still on the active rolls and can be seen flying to various events where classics are appreciated. So, next time you talk to your pilot friends, ask them about their first airplane. You might be surprised how many got their start in the sturdy Cessna 150. 

Editor’s Note: This story originally appeared in the September 2023 issue of Plane & Pilot magazine. 

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Agility Prime, the service’s cutting-edge, vertical lift initiative, explores the operational and training potential of electric vertical takeoff and landing (eVTOL) aircraft for various mission-critical purposes, including training and operations.

• READ MORE: Pipistrel Velis Electro: The World’s First Certified Electric Plane

“AFWERX and MTSI’s selection of the Velis Electro is a powerful endorsement of Pipistrel and the growing acceptance by leading organizations of this area of emerging technology,” Kriya Shortt, president and CEO of Textron’s eAviation segment, said in a release. “This marks an important milestone on the journey to sustainable flight, and we are proud to support the Agility Prime program as the Velis enters its fleet.”

Pipistrel, headquartered in Slovenia, said the Velis Electro stands out as a cost-effective and environmentally friendly choice for flight training, with its mature electric engine design developed in-house by Pipistrel. Company president Gabriel Massey emphasizes the aircraft’s remarkable potential.

“The Velis Electro is a cost-effective and sustainable option for flight training,” Massey said. “With its mature electric engine design…the Velis Electro leads the industry in carrying out more sustainable pilot training and other missions.”

Two Velis Electro aircraft will be directly supported by Pipistrel’s distributor, Lincoln Park Aviation, which the company believes marks a stride toward a greener, more sustainable future in aviation.

The post Pipistrel’s Velis Electro Promises Electric Revolution appeared first on Plane & Pilot Magazine.

Several manufacturers have jumped into what is likely to be a lucrative general aviation market for these microturbines. While the concept of turbine engines remains consistent with all the players, subtle differences between the offerings are present. Before we get into some of the available microturbines, let’s look at what makes an engine a “turbine” and what differentiates the micros from what we know as the “standard” turbine engines widely used today.

The Basics

The truth is all turbine engines are relatively simple. This also adds to their reliability, as there are far fewer moving parts than in an internal combustion engine, and those parts are, unlike piston engines, rotary instead of reciprocating. Regardless of how they’re producing propulsion, whether it’s driving a shaft with a propeller (turboprop), powering the aircraft with a high-speed exhaust (turbojet), or running an internal fan (turbofan), they share a similar design.

All have a core that consists of a compressor—which does just as the name implies—plus a burner, which ignites aforementioned highly compressed and very hot air, and the turbine, which is the point of the first two parts. In the turboprop world, the hot exhaust gas that exits at the main turbine passes through an additional turbine before entering a nozzle. Most of the energy generated by this exhaust at the nozzle is then utilized to turn the secondary turbine. The secondary turbine is connected to a driveshaft and gearbox, which is then directly connected to a propeller, turboprop, or a turbofan.

• READ MORE: A 200-hp Turboprop for Homebuilts

Another benefit of turbine engines is the fuel that feeds their appetites (jet-A) is more readily available worldwide and typically at a lesser cost than its counterpart, avgas, which is short for “aviation gasoline” used in the piston world. In fact, turbine engines are like Mikey from the old Life Cereal TV commercials—they pretty much will consume anything within reason to satisfy their fueling hunger. With that in mind, in addition to jet-A, it’s expected that many of the microturbine engines will also be happy with other forms of kerosene, including over-the-road pump diesel fuel, especially in emergency situations. Manufacturers’ additional testing of these microturbines will ultimately determine what type of alternative fuels, if any, can be used on a permanent basis.

TurbAero

Australian company TurbAero is developing a small, lightweight 200-horsepower engine, which will initially target those experimental aircraft that utilize conventional opposed-piston engines, usually the Lycoming IO-320 or IO-360 varieties (think Van’s Aircraft RVs and the like). TurbAero’s design utilizes a process called “recuperative technology,” taking the air that normally would enter the combustion chamber—in this case at 200 degrees Celsius—and, utilizing a heat exchanger, preheats the air by extracting waste heat from the exhaust gasses—and then uses that to preheat the compressed air, thereby reducing the amount of raw fuel required.

This preheating, or recuperative technology, translates to an engine that can run more efficiently, burn less fuel, and operate with a good balance between performance, size, weight, and cost. A good balancing act, indeed. And, lest you think this is some newfangled technology, it’s actually a proven process that has been utilized on land-based vehicles, such as the M1 Abrams series tanks on the battlefield, with TurbAero resizing the recuperator, right-sizing it for the TA200TP 200-horsepower microturbine with the intent on bringing it to market sometime in 2025.

How did TurbAero get into the microturbine game? As is often the case, the company came about by pure happenstance when its CEO, David Limmer, was looking for a turboprop engine for his own personal experimental aircraft in 2008. Not able to find one, the next best solution was to build one of his own, completing it in 2015. It was during this time Limmer recognized the potential for a range of small turboprop engines for aviation applications, specifically the experimental/builder’s market. Three years later, with funding in place and partnering with his brother, Andrew, TurbAero was formed. After attending numerous aviation symposiums worldwide and talking with various kit airplane manufacturers and many hobbyists, TurbAero settled on development of the 200-horsepower TA200TP engine.

With additional refinements going into the fifth year of development, the company is poised to transition to the next phase, planned for the first quarter of 2024 and culminating in putting the engine through its paces on the test stand. Refinement will follow based on the results of the testing.

One of the current design refinements is optimizing the engine for operation and efficiency at lower altitudes. Like all turbines, these engines are most at home at the higher flight levels. However, TurbAero realizes that to be successful in the experimental market, it’s critical to provide a reasonable level of efficiency at the 10,000 to 12,000-foot range instead of the rarified air in the flight levels at which turbines are generally accustomed to operating. Considering the lower per-gallon price of jet fuel, along with the typically lower cost of maintenance compared to a reciprocating piston engine, and given the potential for higher reliability, the overall cost and benefit to operating the microturbine should likely fall within a range that most aviators in the experimental world would find justifiable, even with a planned price to market at $85,000. With the ultimate goal of bringing these microturbines to the certified market—in all likelihood, probably not for another five to 10 years—the question of overhaul recommendations comes to mind.

Most microturbine manufacturers are looking at TBOs of other certified turbines and seeking to replicate those in the marketplace, with the 3,000-hour TBO as the benchmark for future certification. In the meantime, since these turbines are designed for the experimental market, TBO is not a requirement now, although it’s likely these engine makers will look at safety and provide recommendations of their own long before their microturbine is spooling up in the certified world.

• READ MORE: TurbAero Small Turboprop at EAA AirVenture Oshkosh

In that regard, TurbAero is integrating a data acquisition function into the FADEC (full authority digital engine control) on their TA200TP engine. This purportedly will allow users of this engine to benefit from a health and usage monitoring system, designed to identify potential failure points before the failure occurs. It’s a grand prospect that could save maintenance costs at the very least and bent airframes at the very worst if it comes to fruition.

PBS Aerospace

Another turbine engine manufacturer, PBS Aerospace, brings its experience manufacturing propulsion systems for the defense sector, with expertise in tactical UAVs, target drones, and missiles, and enters the general aviation experimental market with a small, 43-pound micro turbojet engine that’s used in some SubSonex jets, as well as the BD-5J jet.

According to vice president of customer support Frank Jones, the flexibility of the company’s TJ100 turbine engine will allow builders to utilize various versions of it, with some having a fuel-oil mix that will allow straight-up rocket-style launching without skipping a beat.

While PBS suggests a 300-hour time between hot sections at the moment, as additional experience and time gets put into these engines, the manufacturer may increase its suggested time between hot sections. Again, in the experimental world, these are simply suggestions, albeit strong ones. However, because there are so few hours being put on these microturbines, manufacturers like PBS are being ultraconservative in recommendations for overhauling/hot sectioning their turbines.

At this time, PBS turbines in need of maintenance or hot sections require the engine to be returned to the company’s facility in the Czech Republic. However, as of this writing, since none of PBS’ TJ100 engines in the field have accumulated operational hours approaching the 300-hour mark, no overhauls have yet been necessary. Jones says the firm hopes to have facilities in the U.S. available for overhaul purposes when the time comes. In the meantime, as mentioned, other manufacturers are anticipating reaching similar recommended TBOs as their big brother counterparts, meaning 3,000-plus hours before the requisite hot section and overhaul. Pricing of the PBS TJ100 is in the $80,000 range, depending on accessories and other options.

Heron Engines

For those who don’t want to wait for the development of those microturbines still in the testing stage and earlier, there’s one manufacturer—Crete, Greece-based Heron Engines—with a 130-horsepower version ready for preorders. Although you may be sacrificing some available horsepower compared to others that are developing 200 hp versions, the Heron microturbines, weighing in at a svelte 82 pounds, with gearbox and developed after decades of work designing and building UAVs from founding member Alex Vrontoulakis’ father, are available for preorder today. Vrontoulakis is now partnered with Alex Fatseas and since 2018 they have been committed to bringing their microturbines to market, with the company promising to make them affordable (low $40,000s), easy to maintain, with projected overhaul costs in the $7,000 range.

Solar Turbines

You wouldn’t normally think a turbine engine used primarily as a helicopter auxiliary power unit (APU) or ground power generator would be a good fit as a primary source of propulsion. But in the case of the Solar T62, the manufacturer says, you would be wrong. This compact engine continues to see some use in the experimental helicopter world, where it can be found in kits made by Rotor X Aircraft Manufacturing (formerly RotorWay International) and Mosquito Aviation (the single-seat Mosquito homebuilt helicopter). However, you might need to look hard for one of these as they are few and far between, and mostly found on auction sites such as eBay. When you can find one on the market for sale, you can expect to shell out about $15,000 for the T62 turbine—and of course, we’re talking used.

Other Turbine Benefits

Because 100LL is becoming more scarce by the day internationally, industry experts predict per-gallon costs are going to continue their upward spiral. Having an engine that burns jet-A will assure more savings in the future, which will be an added benefit overall.

So, what will it take to enter the rarified air of the turbine world? Like many things in aviation, time and money. Time, since we’re in the infancy stage of microturbine development. And, of course, money, since the price of admission for experimental microturbines will fall somewhere within the $40,000 to $85,000 range and potentially go higher by the time they come to market.

With the advent of these microturbine engines, it’s quite possible we’re at the inception of a new phase in propulsion for experimental aircraft and beyond. While there are numerous obstacles to overcome, not the least of which is the cost of acquisition, obtaining efficient operation at lower altitudes and proving the microturbine design is sustainable in our ever-demanding world of aviation, there’s cautious optimism that in the not-so-distant future, we will all be hearing the unmistakable sweet sounds of turbines spooling up much more frequently at airports around the world. 

Editor’s note: This story originally appeared in the July 2023 issue of Plane & Pilot magazine. 

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