Zenith STOL CH 701: STOL On The Farm - AOPA

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Builder finds Zenith LSA to be a perfect fit, and fun

October 1, 2020 By Mike Collins Share via: Rolling in aileron and stabbing the left rudder, Jon Humberd banks his Zenith Super 701 steeply above some of the 400 cattle on his southeastern Tennessee farm. The grazing bovines are so unconcerned, they don’t even raise their heads.

Fit for the farm

Meet the STOL Bandits

Nobody flies alone

In fall 2019, a group of about a dozen backcountry and STOL pilots, most based within 20 to 30 miles of Chattanooga, came together; they call themselves the STOL Bandits. By sharing knowledge of private airstrips—most uncharted—and other backcountry landing sites, they’ve expanded their collective destination options.

“Some of us were flying around before,” said Tony Armour of Dalton, Georgia, whose first backcountry airplane is the Just Aircraft SuperStol he bought in 2017 (he also owns a Mooney). “Everyone was doing it, but nobody was doing it as a group.”

“I had a J–3 and was landing on sandbars when I was in high school,” said Terry Presley of Lookout Mountain, Georgia. He’s owned several STOL aircraft and has a CubCrafters Carbon Cub FX3 today.

“It started out as a group text. The next thing you know, six or seven planes are meeting somewhere,” said Lee Boyd of Apison, Tennessee, who bought a Carbon Cub SS in 2012. “We just started popping up and flying together. It happened all of a sudden. We’re having fun.”

Some members have flown as far as Texas to participate in STOL competitions.

“I never expected it; I never planned on flying with other people—but I’ve had a blast,” said Jon Humberd, whose Zenith STOL CH 701 is the only nosewheel airplane in the bunch. “I’m blessed to be in a group like this. As the group grows, we’re still seeing new strips within 10 to 15 miles of here that we didn’t know existed.” —MC

Early on, they were afraid of the airplane,” he said. “Once they got used to it, they could cause some trouble by not getting out of the way. If I have to put it down with [the cows], I can’t count on our cows moving.”

His neighbors don’t mind the overflights, either. “I’ve never heard anything negative from the neighbors,” he said. When he sees neighbors below, he’ll fly over and honk the horn, and waves are exchanged. Yes, Humberd installed an automotive horn under the cowl, and activates it by pushing one of the horn buttons, mounted on each side of the Y-shaped control stick in the center of the cockpit.

“I’ll never build another airplane without a horn. I have a lot of fun with that,” he said. “It’s not loud, it’s just enough to have fun with.” Its playful beeps encourage people to look up, and it complements the bright yellow smiley face that’s been on the bottom of the fuselage since the Zenith was completed.

Humberd chose to build so he could get exactly what he wanted, and fit was a primary factor in choosing a short takeoff and landing aircraft. The airplane had to fit in Humberd’s workshop; it had to be able to operate from his 350-foot, downhill runway; and it had to fit Humberd’s 5-foot, 10-inch frame. While other Zenith Aircraft STOL designs have adjustable seats, the light sport 701’s are fixed to the airframe. “It’s one of those deals that you either fit or you don’t,” he said. “It fit me like a glove.” Oh, and it had to fit his budget, too.

He received his STOL CH 701 kit in April 2016; the Super 701 moniker is Humberd’s because of his engine choice—a four-cylinder, 130-horsepower, air-cooled UL Power 350iS. He also calls the airplane his Sky Jeep. “We finished our house in 2017, and I finished the airplane in 2018. Ninety percent of this thing happened between midnight and daylight.” His construction window came after working the farm all day, and family time in the evening. “I enjoyed [building] but I found out real quick I’m not 20 anymore,” the 43-year-old laughed.

Many days, the farm is his aerial playground. Humberd farms 400 acres, raising row crops—soybeans, wheat, and corn—in addition to beef cattle. When crop fields are empty and there’s standing water, he’ll water ski. He can have fun flying for an hour or more and hardly leave the property.

His runway is just 20 miles west of the southern Appalachians. At 4,224 feet, Big Frog Mountain is the tallest nearby peak, looming above the Ocoee River. “That’s kind of my go-to spot,” Humberd said. “It’s cool to be able to fly for 10 or 15 minutes and get to where you can’t see a house.” It’s a year-round destination; fall provides the autumn colors, although winter can be touchy. “If you can catch a snow over there with just the right light, it’s amazing. My favorite is early spring, when everything is coming back to life.” Spring is also best for seeing wildlife, before it’s obscured by foliage.

Humberd built his shop in 2002, and the family later lived there while building a house next door. “My intention was to use it to build hot rods and work on farm equipment,” he said. The ceiling is high and the door is 24 feet wide, to fit a combine harvester. But the 701’s 27-foot wingspan requires several back-and-forth motions to move the airplane through the narrower door.

When it came time to choose an engine, UL Power was a natural for Humberd, who has a preference for air-cooled engines. He and his father operate several German-built Deutz tractors powered by air-cooled diesels. “It’s what I grew up with, and what I know,” he said. “It’s worked really well for us.” And the aircraft engine is modern, with fuel injection and FADEC.

The biggest construction challenge was the cowling, as none were commercially available for the 130-horsepower engine at the time. “That was a learning experience for me. I had never touched the composites world at all. There’s a learning curve, for sure.” After taking an Experimental Aircraft Association composites class in Atlanta, he wrapped the engine in plastic and put it on the airframe, using it as a template for the cowling. It took three tries to get the desired result. “I’m not afraid to try something new—I get that from my dad,” Humberd said.

To settle on a panel design, he printed out full-sized pictures of various avionics and laid them out on the actual panel, Clecoing it into the fuselage for evaluation. “I played with that for a good while,” he said. “As a first-time airplane builder it probably worked out better than I deserved.” Humberd ended up with a GRT Avionics Horizon HX EFIS as his primary display; a GRT Mini-X with backup battery as secondary (normally displaying the engine monitor); a Garmin GTR-200 com radio; an Appareo Stratus ESG ADS-B Out transponder; and a SkyRadar ADS-B receiver. “It’s more capable than I am. It has all the chart screens and approaches that you can think of,” he said. “It’s overkill—it’s maybe a lot of overkill. I chose it mostly because it fit.”

Built at home

LSAs with purpose

So many ways to have fun

Humberd increased the maximum gross weight by 150 pounds above the factory numbers, requiring a recalculation of the airframe’s G limits. He installed several Zenith upgrade options, including extended range fuel tanks, LED lighting, streamlined struts, and outward-domed bubble doors—the latter for increased elbow room and improved visibility. He also added a custom-made, 3-gallon header tank.

His builder’s log, required by the FAA to document construction, is a hardbound photo book consisting of daily progress pictures, and Humberd said the FAA inspectors from the Nashville Flight Standards District Office loved it. But he never recorded his hours worked for the two-year project.

He enjoyed the building experience. “Zenith has been really good to work with,” he said, and the UL Power engine has been easy to install, operate, and maintain. Anyone could build such an airplane, he added. “It’s not out of reach for anybody. It’s about budgeting and making it work.”

He earned his private pilot certificate at nearby Collegedale Municipal Airport, finishing just before he started building the kit.

Humberd’s wife, April Humberd, helped at various points during the build. “We’re outdoors people,” she said. “It’s a way to enjoy nature from a different point of view. It’s definitely a fun adventure. I know it means a lot to Jon, so it means a lot to us.”

She said she helped a lot with riveting and rustproofing. “People say he has a ton of patience, and I laugh,” she laughed. “He is stubborn and determined. He is not patient.”

First flight was August 31, 2018, and after flying off the required hours, his daughter Joslyn Savannah became his first passenger (the video is on YouTube and it’s really cute; search for “Sky Jeep 1st Passenger”). Joslyn, who started kindergarten this fall, has not yet noticed that the airplane’s tail number combines her birthday and initials.

Humberd has flown the airplane about 350 hours. Locally he flies by himself, or with a group of local STOL pilots (see “Meet the STOL Bandits,” p. 54). A flight to Gainesville, Texas, in March for the Lonestar STOL Competition is his longest cross-country so far. He cruises at 90 to 95 mph. “The 701 is a draggy airplane and the fuel burn quickly increases when going above about 90 mph,” he said. But flying around locally at no more than 60 to 65 mph, fuel burn is less than 3 gallons per hour.

“I just like to fly. If I can push it out of here and get up in it, that’s what I like to do—even if it’s just for an hour around here.”

Getting started

Flying wasn’t really a dream for Humberd when he constructed the shop, although he was flying radio-controlled aircraft at the time. Around 2010, he purchased an Ultraflight Lazair ultralight, flying it from a smaller strip on the farm. It got him hooked on low-and-slow flying. After rats nested in the ultralight, ruining the fabric, he decided to move into something all metal—and with a nosewheel to keep the tail off the ground, so that problem could not recur.

“I wanted something that would take the place of the ultralight and let me fly around with a passenger,” and the Zenith filled the bill. And it’s a lot quieter than the twin-engine ultralight with straight-pipe exhausts.

On June 22, 2020, Humberd damaged the Zenith’s left wing when it hit a fencepost after straying from the center of his taxiway, while taxiing back to the shop with the nosewheel off the ground. He decided to replace the wing. “Stuff happens,” he said. “It cost me a month. That’s a lot of work to do in a month.” But a downdraft paint booth in the basement, originally designed for hot-rod work, sped painting of the new wing. “I think the takeaway is that if you’re going to fly and play, you’re going to beat something up.”

Humberd plans to install a three-blade electric constant-speed propeller with a new spinner. He’s also thinking seriously about building a three-place Zenith STOL CH 750 SD (Super Duty) so that he, his wife, and their daughter can fly together.

Zenith’s STOL CH 750 can be built with a 1,320-pound maximum gross weight to qualify as a light sport aircraft, but the CH 750 SD has a design gross weight of 1,900 pounds that Humberd probably would increase to 2,050, in part to compete in a higher class at some STOL contests.

If that happens, however, don’t expect Humberd to part with his Super 701—it’s too much fun to fly and too economical, burning about half the fuel “for the same fun factor,” he said. That means a new hangar’s probably in his future, as well.

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Affordable STOL for 44 years

The future is electric

The original STOL CH 701 has returned to the skies after being neglected for two decades in the back of a barn. Aeronautical engineer Chris Heintz built it in 1986, combining the advantages of a traditional airplane with the short-field capabilities of an ultralight, and it soon became popular with builders and pilots alike. Fixed leading-edge slats and full-span flaperons enhance its STOL capabilities. Per Dahlstrom of Vancouver Island, British Columbia, Canada, now owns the original.

“We’re pretty proud of the history and the lineage of the airplane,” said Sebastien Heintz, president of Zenith Aircraft Company and son of designer Chris Heintz. “The ultralight market showed people you could have fun-to-fly aircraft that were affordable. He basically designed the 701 as a modern ultralight.” The STOL CH 701’s light weight made it a light sport aircraft long before the category existed.

The design was inspired by the Fieseler Storch, a World War II-era German liaison aircraft, Heintz said, and modernized with a semi-monocoque stressed fuselage, side-by-side seating, and tricycle gear. In the 1990s, the four-cycle Rotax 912 engine made it more reliable as a utility airplane. “It wasn’t just a toy anymore.”

The 912 led to the introduction of the 701 SP, with a higher gross weight to accommodate the heavier engine. The STOL CH 750 was designed specifically for the light sport aircraft category, with a 1,320-pound maximum gross weight. The four-place CH 801 was introduced in the late 1990s. And at Oshkosh 2017, Zenith introduced the CH 750 Super Duty—basically a larger 750 with a wider wingspan, longer cabin, larger tail, and a third seat. The 750 and 801 include independent, adjustable seats and other features not found in the 701.

Because most customers are first-time builders, Heintz has worked to improve the kits, using CNC machining to cut and predrill the metal. “My challenge is developing a kit that is complete and easy to build,” he said. “We really simplified the process.” Although the 701 remains available, that kit has not been upgraded with CNC parts, and the 750 is a quicker build. “The 750, in many respects, is the replacement for the 701.”

Zenith does not currently offer any manufactured special light sport aircraft, he noted, in part because it would eliminate the ability for buyers to customize engine and avionics choices. But there are several builder-assist programs and a good used-aircraft market, he said, and Zenith is working on electric. “I think electric power will do very well with the STOL aircraft.” —MC

Spec Sheet

Zenith Aircraft STOL CH 701

Kit price: Low $50,000s | Price as tested: About $80,000

Specifications Powerplant | UL Power 350iS, 130 hp Recommended TBO | 1,500 hr Propeller | Whirlwind ground adjustable 3-blade Length | 20 ft 11 in Height | 8 ft 7 in Wingspan | 27 ft Wing area | 122 sq ft Wing loading | 9 lb/sq ft Power loading | 8.5 lb/hp Seats | 2 Cabin width | 3 ft 4 in Cabin width, bubble doors | 3 ft 8 in Empty weight, standard kit | 580 lb Empty weight, as built | 700 lb Max gross weight, standard kit | 1,100 lb Max gross weight, as built | 1,250 lb Useful load, standard kit | 520 lb Useful load, as built | 550 lb Payload w/full fuel, as built | 388 lb Max takeoff weight | 1,250 lb Max landing weight | 1,250 lb Fuel capacity, standard kit, ext range tanks | 24 gal (23 gal usable) 144 lb (138 lb usable) Fuel capacity, as built w/header tank | 27 gal (26 gal usable) 162 lb (156 lb usable) Oil capacity | 3.5 qt Baggage capacity | 50 lb

Performance Takeoff distance, ground roll | 50 ft Takeoff distance over 50-ft obstacle | 200 ft Rate of climb, sea level | 1,200 fpm Max level speed, sea level | 110 mph Cruise speed/endurance w/45-min rsv, std fuel (fuel consumption) @ 70% power, best economy | 90 mph/ 4.5 hr 6,500 ft | (5 gph/30 pph) Max operating altitude | 12,500 ft Landing distance over 50-ft obstacle | 200 ft Landing distance, ground roll | 80 ft

Limiting and Recommended Airspeeds VX (best angle of climb) | 35 mph VY (best rate of climb) | 60 mph VA (design maneuvering) | 71 mph VFE (max flap extended) | 63 mph VNO (max structural cruising) | 99 mph VNE (never exceed) | 110 mph VS1 (stall, clean) | 29 mph

For more information, contact kit manufacturer Zenith Aircraft Company, 1881 Airport Road, Mexico, Missouri 65265; 573-581-9000.

All specifications are based on manufacturer’s calculations. All performance figures are based on standard day, standard atmosphere, sea level, gross weight conditions unless otherwise noted.

Mike Collins Technical Editor Mike Collins, AOPA technical editor and director of business development, died at age 59 on February 25, 2021. He was an integral part of the AOPA Media team for nearly 30 years, and held many key editorial roles at AOPA Pilot, Flight Training, and AOPA Online. He was a gifted writer, editor, photographer, audio storyteller, and videographer, and was an instrument-rated pilot and drone pilot. Go to Mike Collins's Profile

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