Exploring the Unique Sorrell SNS-7 Hiperbipe

First of all, what is a Hiperbipe? Secondly, look at that paint job. And then there’s Matthews, quite the colorful figure in the aviation community of the Carolinas. 

So, what’s a Hiperbipe? The Sorrell SNS-7 Hiperbipe is a unique American homebuilt aerobatic cabin biplane. “SNS” stands for Sorrell Negative Stagger, referring to the lower wing positioned ahead of the upper. 

“Hiperbipe” is shorthand for high performance. The design was conceived by Hobie Sorrell and his sons, John, Mark, and Tim, through Sorrell Aviation, founded in 1958 in Tenino, Washington. The company ceased operations in 1983, but Thunderbird Aviation acquired the rights and tooling in 2015. 

In 1973, Sorrell Aviation designed an experimental homebuilt kit that promised to give full unlimited aerobatic performance without sacrificing the comforts of a cabin-style aircraft. The result was a design that mixed wood and fabric with metal construction. 

The wings are made from wood, with wooden-stressed skin, and the airframe is covered in doped aircraft fabric. The fuselage, tail, and flight controls are all built from steel, and the engine cowling is fiberglass. 

Meet Mikey 

Michael Matthews, 46, is an ATP, MEII, and ASES with type ratings in the Westwind 1124, IAI jet, EMB-145, Falcon 900 and 2000. Phew! 

He is known to everyone as Mikey, a well-known fixture at just about every event in the Carolinas and Virginia. 

“I grew up in a flying family,” Matthews said. “My dad, Rick Matthews, was an Army helicopter guy in the Vietnam era. Later, he over in Salisbury, North Carolina [KRUQ].” 

Matthews’ family had a Cessna 170 that his dad used to run back and forth to Salisbury on his weekend National Guard duties. He grew up around that 170 and the helicopters, and he points to that airplane for jump-starting his flying obsession in taildraggers. 

Surprisingly, Matthews did not solo until he was about 20 years old. 

“I trained at Mount Airy [KMWK in North Carolina], which most people have never heard of, but everyone knows what ‘Mayberry RFD’ is,” he said. “And, no, I never met Opie! I learned under the tutelage of Ed Holland, who is a primary instructor and still a good friend of mine. I earned my CFI and trained at Conway, South Carolina. Somehow, I ended up out in Las Vegas instructing for a large flight school, West Air Aviation.” 

While out West, Matthews jumped headfirst into the world of aerobatics. 

Craig “Brute” Teft was a legendary airshow performer and CFI. Teft was also a retired fighter pilot and former Top Gun instructor. 

“I had the privilege to learn upset recovery and aerobatics under Brute,” Matthews said. “I had a little aerobatic time back home, just flying experimentals and doing the occasional loop. But that was my first real aerobatic training experience. I loved it, and jumped into it all the way. I also landed a side gig towing gliders in Jean, Nevada, on the southwest side of Las Vegas. Additionally, I instructed in a Decathlon and a Pitts on a government contract with the Air Force for upset recovery within the Initial Flight Training [IFT] program.” 

Matthews came back to North Carolina in 2005, where NASCAR auto racing reigns supreme, and started working for some of the circuit’s flight departments. His first corporate job was flying an E-120 Brasilia for driver Dale Earnhardt Jr. Later, he worked for Richard and Kyle Petty for almost eight years, flying the Westwind and Astra, and instructing Kyle on his Columbia 400. 

Shortly after that, Matthews and his brother Casey bought a standard Decathlon with 150 hp. Once Casey got his private pilot certificate, they started an aerobatic flight school called Acro Dynamics in Mooresville, North Carolina. The company supports the International Aerobatic Club, which promotes and enhances the safety and enjoyment of sport aerobatics. They ran Acro Dynamics for over 10 years, with two different Decathlons, and have trained hundreds of pilots to earn a variety of ratings, including CFI, spin endorsements, base aerobatics, upset recovery, and tailwheel endorsements. 

‘Had to Have One’ 

Matthews bought his Hiperbipe in October 2019. 

“Ever since I saw one, I just knew I had to have one,” he said. “This particular kit was sold in 1977 and was certified in 1980… I am a 1979 model, so it is two years older than I am. It was built by a fellow named Frank Psota, who lived in Illinois. During its lifetime, it bounced around through several different owners, but I picked it up from a gentleman down in Alexandria, Louisiana, who had owned it for some 16 years. He was getting up there in age, and he was having trouble keeping up with it. However, it looked like it had only 600 hours on the airframe.” 

When Matthews bought it,it was in dire need of some TLC. That’s why he calls it a “rescue plane.” 

He said the Hiperbipe had been in flying condition the week prior he purchased it. The owner had been out flying a lot of aerobatics when a cylinder blew off. He made it back to his airport unscathed, but he knew that he was going to have to overhaul that motor. At his age, he just did not want to put the time, effort, and money into it, so he sold it to Matthews, knowing that it was going to somebody who was going to fix it up and take good care of it. 

“Casey and I went down to Louisiana and rented the biggest box truck we could get,” Matthews said. “The Hiperbipe wouldn’t fit in there. It wasn’t a length thing. It was a width thing. It lacked about three-quarters of an inch fitting into the truck. Oh, man, we thought about taking the wheels off, but just the axles were just a hair too wide. We just could not get it in the truck.” 

Finally, they built some ramps and rolled the airplane into the truck, tail first, and bolted it to the bumper. 

They bolted the door up and left about 4 feet of the airplane hanging out of the back of the truck and drove it home that way. 

In fact, they drove 850-plus miles, mostly at night, with the wheels conveniently covering the brake lights. Matthews said that they got some looks [from] some police officers, but “…I think they were more entertained than anything.”

It was kind of a COVID-19 project for Matthews—and he got right to work. It took him about 11 months, working on it almost day in and day out to get it whipped back into shape. The wing spars are made from wood, and the wing skin is plywood covered in doped aircraft fabric. He paid particular attention to these areas and completed the project in late 2020. 

“It offers everything I could want,” he said. “It’s an aerobatic airplane that has exceeded my expectations for everything that it does. Despite its aerobatic roots, it is a comfortable, cross-country airplane with decent legs. It does a pretty good job at all those.” 

Matthews set out to do a number of upgrades. He started by removing the engine, an IO-360-C1C, rated at 180 hp. He did a direct replacement engine at that point. He bought one from Atlanta Air Salvage and took both motors to Tom Schwietz at Valley Aircraft Engines in the Shenandoah Valley for the total overhaul. The “new” engine was a rebuilt C1C with a compression modification, resulting in an estimated 220 hp. 

“My average climb rate is probably somewhere around 1,2000 to 1,500 feet a minute, with a couple of people in there and a half tank of gas,” he said. “During the wintertime, I see numbers as high as a 2,400-foot- a-minute climb rate, and that is sustained. So, it is a climber, pretty draggy with two wings and some struts. It’s not the fastest biplane out there, but I think it is respectable at about a 155- to a 160-mile-an-hour cruise. It’s a little weight sensitive with full tanks and two people in it, but it is not bad on gas. 

“At 155-160 mph, it burns about 10-10.5 gallons per hour. I do not have a smoke system. A lot of people ask me—and I love smoke—but I certainly don’t love cleaning it up. The smoke systems are great with RV guys that have metal bellies, but I’ve got a fabric belly. I had to recover that fabric belly when I first bought it, and a smoke system just isn’t worth it for the weight and the mess. I do not leave a chem trail, but it makes noise…and that is good enough for me.” 

Although Sorrell Aviation went out of business, Ron Jones recognized an interest in the Sorrell SNS-2, SNS-8, and SNS-9, and formed Thunderbird Aviation in 2002. In 2013 the rights and tooling became available for the Hiperbipe, and Thunderbird added the SNS-7 to its product line. 

Jones told Plane & Pilot that, to date, Thunderbird has not sold any SNS-7 kits or completed aircraft, but the company does have the tooling to produce any component needed for it. He added that he is looking at the possibility of building metal wings, which would be a welcome solution to what many see as the Hiperbipe’s Achilles’ heel—the wooden wings. 

So, while there are no new Hiperbipes being built now, at least the current community can be assured of finding parts when parts are needed. 

Then, there’s the paint scheme on Matthews’ Hiperbipe, certainly something that sets it apart. Telling the story gets him smiling every time. 

“The plane was basically a blank canvas when I got it,” he said. “It had some vinyl stripes on it. We pulled those off and got the airplane nice and clean. So, for starters, the fuselage is sort of the shape of a shark, so that is where we started. I guess the plane needed to be gray like a shark, and we had to wait until September for the temperature and humidity to be right. We painted the plane right there in our driveway. I decided to name it. At first, I thought ‘Hammer- head’ would be an obvious choice, because of the aerobatic maneuver. But it does not look like a hammerhead, so I decided on Mako, which just happens to be the fastest shark in the ocean. 

“We sat down with Jim Gravlin at Red Eye Designs in Mooresville. These guys wrap all these NASCAR race cars, and they did a phenomenal job with us. I took a piece of paper and plopped it on Jim’s desk. I said, ‘This is what I want to do on the front of the airplane. Can you design it? Also, by the way, here’s a logo idea. I drew it out on paper, which is the Mako logo. …By the second draft, we had it done. All the gray that you see there is paint, and all the graphics are vinyl from Red Eye Designs.”

With that he pointed to the red eyes on the shark’s face: “That’s a shout out to them.”

Matthews also wants to recognize the work of Chris Farrell at Farrell Craft in Huntersville, North Carolina. 

“Chris helped me with multiple fabrication, welding, and avionics projects on this airplane,” he said. “He was [NASCAR team owner] Jack Roush’s right hand man at the race shop and also in his P-51 hangar. He is also a pilot with a Cessna 140 over at Miller Air Park [NC39 in Mooresville] and is one of the best fabricators I’ve ever come in contact with. He helped me reset the landing gear tow, fabricate a panel patch for my Avionics, [and] repaired my engine mount and multiple other alterations on the airplane.” 

When Matthews is not flying as PIC on a Falcon 900 for Sonic Automotive and Speedway Motorsports, he is probably spending quality time with Mako. If he is in town, there is a good chance you will find him at one of the many local fly-ins in North Carolina and South Carolina, as well as Virginia. 

In fact, at the Flying Horseman Ranch Fly-In this year at Landis Airpark (VG16) in Stuart, Virginia, Matthews was joined by Jack Gavin in another Hiperbipe, offering a rare photo opportunity to capture two of the type flying in formation. Mako has a way of making people smile.