A higher maximum gross weight for all Sonex and Waiex aircraft powered by engines of 100 hp or greater has been approved.
Following a series of engineering studies and flight tests, Sonex and Waiex owners may designate a maximum gross weight of 1,220 pound for aircraft with 100 hp or more. This represents a 70-pound increase vs. the previous 1,150 pound limit and is applicable to both A-Model (Legacy) and B-Model aircraft, according to officials with Sonex Aircraft.
“We expect these changes to be very popular and greatly expand the appeal of the Sonex and Waiex to today’s homebuilder,” said Sonex owner and president Mark Schaible. “Due to the aerobatic load limit capability of the two aircraft models and the impending MOSAIC changes to the Light Sport Aircraft rules, we took the opportunity to study this change to our specifications.”
While this additional gross weight allowance was originally intended for adoption after the FAA MOSAIC NPRM takes effect as a final rule with an increase in allowable stall speeds for Sport Pilots, the Sonex team said they are “pleased to report that stall speeds observed between the two test aircraft are still within current Light Sport Aircraft limits.”
Stall speed at 1,220 pounds gross weight:
- Clean Stall Speed: 50 mph
- Full Flaps Stall Speed: 43 mph
Owners of complete and flying Sonex and Waiex aircraft wishing to make this change can do so in accordance with their individual aircraft’s operating limitations, according to Sonex officials.
Changing the gross weight constitutes a “major change,” and would be handled in the same manner as any other major change to an Experimental Amateur Built aircraft (installing a different prop or engine, floats, etc.), officials noted.
“The operating limitations issued to the aircraft will include a process for incorporating a major change,” company officials explain. “For most operating limitations issued in the past 20 years or more, this will involve contacting the FAA FSDO to get a flight test area approved, then moving the aircraft back into Phase 1 flight testing via an aircraft logbook entry. The owner/operator would then test the aircraft up to the new gross weight, document the new performance characteristics (stall speeds, climb and glide rates, CG compatibility, etc.) for a minimum of five hours. Once the flight testing is completed, the owner/operator would then make another logbook entry, per the guidance found in the operating limitations, to move the aircraft back into phase 2 normal operations.”
For more information: SonexAircraft.com
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