Slowing down matters as much as accelerating in most auto racing, and the same is true of STOL Drag racing. Unlike traditional Reno-style pylon racing, which involves no slowing down whatsoever, STOL Drag requires starting and stopping twice while flying less than a mile.

I have never been to a STOL Drag race, and so I will probably be pummeled for whatever I say, but here goes anyway.

Two pylons and corresponding start/stop lines are set 2,000 feet apart. A third pylon is placed at the 1,000-foot mark, just for reference. The idea is to take off from the first line, fly to the far line, land, come to a full stop, turn around, and repeat the process without touching the ground between the lines. Two airplanes compete side by side, and the winner is the one that first comes to a full stop at the end of the race. Best times are just over 50 seconds, so, for a pleasurable activity, it’s brief.

In principle anyone can participate, but the really serious competitors use highly modified airplanes that can accelerate like mad and stop very short after touching down. However, competitors are paired off according to aircraft performance, so it wouldn’t be unusual to see a Skylane compete against a Beech Bonanza.

• READ MORE: Valdez Fly-In STOL Competition Celebrates 20th Anniversary

Since it’s a time trial, the race rewards acceleration, speed on the airborne segment, and deceleration after each landing. But the equation is complicated by the need to begin to slow down long before reaching the far pylon. Pilots accomplish this by chopping power, kicking in full rudder, and slipping toward the line. But even this phase isn’t as simple as it sounds. Airplanes decelerate quicker with wheel braking than aerodynamic braking, so while it may seem as if it’s best to touch down at minimum speed to reduce the rollout distance, it may actually be better to get the wheels on the ground as quickly as possible, even a few knots above the stall speed.

Initial acceleration is a function of the airplane’s mass and the engine-propeller combination’s thrust. Big thrust requires lots of power and a big prop. Two of the dominant competitors in the sport, Toby Ashley and Steve Henry, fly a Carbon Cub and Just Aircraft Highlander, respectively.

(Henry’s Nampa, Idaho, company, Wild West Aircraft, sells the Highlander as a light sport kit.) Neither racing airplane has much in common with its ordinary Lycoming- or Rotax-powered brethren. Both use liquid-cooled, geared, turbocharged, intercooled engines with very big props. They say the engines put out around 400 hp. The airplanes are stripped down, competing at weights less than 1,000 pounds. Since they are generating more than 2,000 pounds of static thrust, and therefore achieve an initial acceleration of 2Gs or more, it’s not surprising that both get airborne in a couple of seconds and a few dozen feet.

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

The powerful initial acceleration does not last long, however, because thrust diminishes as speed increases, and drag grows in proportion to the square of speed. At 90 knots, which an airplane accelerating at an average 1G would reach in five seconds and 400 feet, drag has increased to more than 200 pounds and thrust is cut in half. Since the drag can be subtracted from the thrust to get the net force accelerating the mass of the airplane, it follows that the forward acceleration may already be well under 1G.

The actual segment times, based on videos of Henry racing at Reno last year, are, as you would guess, asymmetrical, reflecting the fact that it is easier to speed up than slow down. From brake release to throttle down at midcourse, about 10 seconds elapse. From there to wheels on, another 10, but at that point the airplane is still moving at around its stall speed of 35 knots. The rollout takes four seconds and another four to get turned around. The times going back are similar for a total of 52 seconds.

If the average acceleration up to the middle of the course were two-thirds of a G, the maximum speed attained would be about 125 knots. If the touchdown speed at the far end were 35 knots, the average deceleration in the slip would be a bit under under one-half G—more at the start and less at the end. By the time the wheels touch the ground, the rate of deceleration is pretty low. Wheel braking brings it back up to the half-G level.

• READ MORE: Valdez STOL Competition & Fly-In Air Show Marks 20 Years of Excellence

The Carbon Cub and Highlander regularly finish within a fraction of a second of each other, and successive heats also differ by small amounts. That consistency is a testament to the pilots’ skills, since, as you find when you watch any of Henry’s cockpit videos, quite a lot goes on during the brief race. Everything hinges on the deceleration timing, staying as low as possible, and amount of wheel braking that can be applied without nosing over.

Henry claims to use his airplane as a daily driver—probably at about 20 percent of power. But I suppose that if STOL Drag racing continues to be popular, it may eventually engender purpose-built airplanes. Very likely the slip-to-slow-down approach would be supplemented or replaced by large air brakes that would add several square feet to the airplane’s equivalent flat plate area. Maybe a slight edge in acceleration could be gained by cleaning up the front end, replacing the big intercooler radiator with a small tank of ice water, and getting engine cooling air to the main radiator with a scoop and duct. But aerodynamic refinement may be pointless, since so little time is spent at high speed.

High wings and a tailwheel are taken for granted on STOL airplanes for a lot of practical reasons. But I wonder whether a low wing with some extra span—taking better advantage of ground effect—and tricycle gear with brakes on all three wheels might bring some advantages. Add lots of horsepower and an airfoil with a maximum lift coefficient of two, and then…off to the races!

This column first appeared in the April 2024/Issue 947 of FLYING’s print edition.

The post Looking at the Physics of STOL Drag appeared first on FLYING Magazine.

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.

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.

The P2012 STOL switches out the original Traveller’s Lycoming TEO-540-C1As for Continental GTSIO-520-S engines. At its maximum takeoff weight of 8,113 pounds, the 11-seat STOL model will have a takeoff distance of 1,394 feet compared to the standard Traveller’s 2,596 while offering a landing distance of 1,181 feet at its maximum landing weight of 8,003 pounds. The standard version is capable of landing in 2,438 feet.

“Addressing the needs of a market niche that has been underdeveloped and unsupported for decades, Tecnam once again provides a solution for operators seeking a modern, spacious, comfortable, safe yet stylish aircraft with outstanding STOL capabilities for their business,” the Italy-based company said in a statement. “The P2012 STOL is the only twin-piston aircraft with short takeoff and landing capabilities that [comply] with the latest certification changes.”

• READ MORE: Tecnam Introduces P2012 STOL To Serve Challenging, Remote Airports

Equipped with the Garmin G1000 NXi avionics suite, the Tecnam P2012 STOL has a top cruise speed of 185 knots, 905 nm range, and useful load of 2,831 pounds. The IFR-capable aircraft can be configured for missions including passenger transport, cargo, and air ambulance operations. Tecnam expects to begin P2012 STOL deliveries in January.

Expanding U.S. Partnerships

Italy-based Tecnam also announced at NBAA-BACE the launch of a new dedicated maintenance training program in partnership with Florida-based Aero Affinity Holding Corp.. According to Tecnam, courses will be available for its entire fleet. Tecnam noted that those who successfully complete the courses will be eligible to become an authorized Tecnam Service Center. Courses will be offered in locations including Ontario, Canada; Florida; and California.

“The American market is strategic for Tecnam,” said Umberto Giannotta, the company’s service delivery manager. “We want customers and technicians to be competent and comfortable flying and servicing the aircraft.”

In addition, Tecnam appointed Southern Cross Aviation as a spare parts distributor for the P2012 series in the U.S. Headquartered in Fort Lauderdale, Florida, Southern Cross also has a distribution hub in Anchorage, Alaska, and is planning to open a facility in Mesa, Arizona. Tecnam said the partnership aims to provide an “enhanced experience for P2012 operators across the country” in light of “many more” scheduled aircraft deliveries in the Americas. 

The post Tecnam P2012 STOL on Track for 2023 Certification appeared first on FLYING Magazine.

Eyes open, I’m assaulted by the day-glo orange of the hyperlight tent I’m lying inside. There’s a bucolic moment where I hear birdsong—and then something else. The rapid beating of blades on air. A helicopter: big, inbound. Where was that helicopter pad staked out?

The dome of the tent starts to move. Crap. Did I even tie down this thing when we crawled inside it last night? I know I tied down the airplane. I look over at my sleeping partner, who is snoring away in his sleeping bag. He’s heavy enough; we’re not going anywhere. 

Ugh. I heave myself to a sitting position and pull on my shorts. I crawl to the door (this is a backpacking tent—not stand-up, even for me). 

“Zippers should be banned,” I mumble, forcing myself to be gentle as not to tear the seams. Feet out, shoes slipped on, I emerge on hands and knees into a spray of dew off the rather-wet turf. My eyebrows are being blown back by the turbulence generated by the landing Coast Guard helicopter. Standing, I watch as an ambulance trundles up and disgorges a patient onto a stretcher. Within a minute, they are secured on board, and the wind pummels the tent once more as the rescuers depart. Then back to birdsong. And I remember my bladder—run!

No, actually. I don’t run anywhere anymore. Late middle age is not always kind to former athletes. Maybe I just pick up the pace a little bit and usher a prayer of thanks that I am not forced to wait in a line for the bathroom dedicated to campers on this airfield. Inside, it is clean and warm, if a little damp from the previous occupant, who clearly showered. Functional. I’ll take it. 

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If you’re reading this column because you think I’m going to teach you something about backcountry flying, turn the page. I’m flying a Van’s RV-10. I can certainly land on an excellently maintained grass field (thank you, Triple Tree), but rough or unimproved mountain airstrips are not on my list of options for anything but dire emergencies. 

Why Camp?

I do carry camping equipment on my long cross-country flights, however, for dual reasons: emergencies and because my retired airline-pilot husband and I are frugal. We like to go to really interesting places, but we don’t like paying for fancy lodging. Every now and again, we’ll indulge in a little group air-camping too. It’s nice having friends to share a meal and bonfire. Less nice having friends see me in my camp pajamas pre-coffee the next morning, but hey, trade-offs, right? 

When we travel solo, it is delightful to go places such as where I am now, Orcas Island, Washington, which allows airfield camping. It means we can afford a holiday in a secluded paradise where other accommodations are priced for those who value luxury. Town is an easy stroll from the airport, shops run from tony to kitschy, and waterside dining abounds. Renting a bicycle or car opens up miles of parklands, beaches, and even two modest mountains worth summiting. Renting something that floats might result in wildlife encounters you’ll remember for a lifetime.

I can afford all that if I camp. Yeah, I’m cranky in the mornings until I get a couple of cups of coffee and a good stretch, but to date, it’s all been worth the price of admission. 

Your Checklist

We find airfields such as Orcas by referencing the Recreational Aviation Foundation Airfield Guide. The graphics here are descriptive, and the page loads and updates quickly, depicting airports with camping all over the US, as well as those with co-located hotels or cabins, restaurants and recreational activities. Beyond that the guide provides a “relative hazard index” to help you decide if the airfield meets safety specs for your aircraft’s capabilities and your current pilot proficiency. 

How do I stay comfortable while camping? A quality hyperlight tent is key. You don’t want your camping equipment to put you over gross. Are you one or two people? Get the four-person tent if you are two. Get the two-person tent if you are one. These companies all exaggerate tent floor space. 

• READ MORE: Amy Laboda Archive

Can you walk under your airplane’s wing? Consider bringing a tarp you can sling over a wing and tie down. Pitch your tent under the tarp and enjoy a much drier experience. Tarps are great sunshades too. It is lovely to set up a couple of lightweight camp chairs and a camp table under the tarp in the afternoon to watch arrivals and departures off the nearby runway, or in quieter venues to study the sunlight as it shifts on water or mountains, or both. With a low wing, we use our tarp as a ground cover, to keep the tent floor from getting too damp and facilitate faster breaking of camp. 

My sleeping bag is down, but I can shake the filling so it is all on the bottom, providing me with a comfortable three-season mummy bag that weighs about 2 pounds and takes up almost no space. My sleeping pad is self-inflating and probably inadequate, but you can’t get two giant pads in a little backpacking tent. Anyhow, if my pad was comfortable, my partner says I’d never book a hotel room on vacation, and I’d ruin the economy, right? 

For cookstoves, I am a minimalist. I only boil water on mine. I will cook but strictly things that can be made with boiling water. Mostly, I use my AeroPress to make coffee every day. That said, I do carry instant ramen noodles, instant oatmeal and Lipton onion-soup mix in my emergency pack. You never know. 

I don’t carry a compressed gas cookstove in my unpressurized airplane. Call it risk management. My minuscule stove folds open, and heat is generated by burning fish-oil briquets. They are hermetically sealed so they don’t smell, and they generate a ton of heat and light with one match. When cool, said stove slips inside the simple foam cooler we carry just in case we are going to a more-remote spot and need a few groceries. That said, most of my camp shopping is for salami, fresh baguettes, hard cheese, shelf-stable cream and refreshing beverages. Deli sandwiches, chips with canned dip and maybe more coffee. 

No matter what you do when you’re air-camping, never run out of coffee. Just laugh about the rest. That’s what makes it fun. 

Editor’s Note: This article originally appeared in the December 2021 issue of FLYING.

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