Sonex high-wing design deep dive

This is the first update Sonex has put out about its high-wing configuration since the company’s original announcement in 2021.

The aircraft design has come a long way in the past 17 months, but those hoping to see a prototype will have to wait a little bit longer. Mark Schaible, Sonex owner and president, said, “We have not started cutting metal yet, that will be happening here soon.” Schaible also said that the company plans to debut a prototype at EAA AirVenture Oshkosh 2023.

The Sonex Highwing is Schaible’s first full aircraft design, although he has been involved in the design and engineering of other recent Sonex projects. “I believe very much in the mission of the aircraft and [its] configuration,” Schaible said in an email, “and therefore how important it will be for company sales once [it's] introduced: As I mention in the webinar, my goal has been to make it a Goldilocks in-terms of being just the right size with just the right useful load to make an economical kit and [special light sport aircraft] S-LSA offering while staying true to our company philosophies of aircraft design, construction and mission.”

Sonex’s new high-wing configuration, officially named the “Sonex Highwing” or simply “SH,” is planned to be approved for aerobatics with two people, making the new aircraft capable of aerobatic training as a factory-built LSA, a first for the company. Aerobatic flight with two aboard will require replacing the standard full-span fiberglass wing tips with simple metal end plates.

With a higher useful load than the Sonex-B, the high-wing airplane will be able to accommodate the optional BRS aircraft parachute recovery system.

Owners will have the option to have either a single control stick or Y-grip in the center of the cabin, or traditional dual sticks. The company said the stick configuration can be changed based on specific flight missions like “carrying very young passengers or bulky cargo in the right seat with no stick installed while having a stick between the left seat pilot’s legs or in the center console.” The company says the customizability of the stick configuration will have a “negligible” weight increase compared to a nonconvertible system.

The aircraft is designed for easier cockpit entry and exit with large doors, exposed foot wells, a step-in height of less than 2 feet, and wing height of around 4.5 feet; the exact dimensions vary between available tricycle gear and tailwheel configurations. Pilots who may not have fit as well in the Sonex-B may be pleasantly surprised to learn that the Highwing was designed to have the pilots sit 2 inches farther aft and 2 inches lower than the low-wing Sonex-B. The Sonex Highwing is designed with a 42-inch interior width at the pilots’ shoulders and is also planned to be able to accommodate taller pilots than the Sonex-B with open space in the cabin between the aircraft's aft root ribs.

The outboard wing panels of this trailer-friendly aircraft are designed to be removable using a knuckle design that attaches the outboard and inboard main wing spars. The knuckle method is currently being evaluated against the multi-bolt attach method used on the SubSonex Personal Jet for weight and cost impacts.

Those hoping to option the Waiex Y-tail on their Sonex Highwing will be disappointed to learn that Sonex has reversed its plan to offer this tail variation. The company explained, “CFD studies have shown that the wash from the wing in a high wing configuration would cause severe turbulence for a Y-Tail configuration. Our apologies to Waiex fans, but flight qualities would be unacceptable.”

Schaible explained that Sonex hopes to be shipping kits, or at the very least tail kits to start, by the end of this year. As with previous designs, the company plans to accept refundable deposits to get buyers on a waiting list before officially opening orders. A similar approach to reservations may be taken on the SLSA variants of the Sonex Highwing, but the company is currently evaluating that option.

Sonex has not announced an official price for the aircraft, but Schaible said the company's goal, in today's market and dollars, is to set the price somewhere in the high $30,000 range or less, similar to the cost of the Complete Airframe Kit price of the Xenos-B motorglider, and there will be an additional upgrade cost for Quick Build Kits. For the SLSA version, Schaible said, it’s “far too early to tell,” but Sonex plans to price it competitively with other SLSAs.

The Sonex Highwing will be offered in Complete Airframe Kits, aircraft Sub-Kits, and Quick-Build Kits, as an SLSA, and, depending on demand, Experimental LSA kits. More specifications and information on the Sonex Highwing can be found online.