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Sport Acro Flight Test Report and Video On-Line!

Sport Acro flight testing continues to progress! We have now completed installation of the on-board video camera system in order to show the Sport Acro's capabilities to the world. Test pilot Roger Tanner, who previously conducted flight testing on the Xenos and Waiex aircraft, flew the Sport Acro in August, and has written a report about his impressions of the aircraft. We have edited a video showing clips of Roger's flight, along with some recent footage of Sonex Founder and President John Monnett flying the aircraft. More flying and more video footage will be coming soon!

See Sport Acro Flight Report and Video!

Sport Acro Ailerons Available!

Sport Acro Ailerons for Sonex and Waiex aircraft are now available! All new Sonex and Waiex Complete Airframe Kits shipped after February 1, 2008 include SNX-Z02-01 58” Universal Aileron Skin* stock that may be trimmed appropriately to fit either traditional or Sport Acro aileron dimensions. Also included are all flap and aileron ribs required to perform either installation, along with all required documentation.

Sonex and Waiex Builders may retrofit their existing aircraft. The parts required for a Sport Acro Aileron and Flap installation are detailed in the table below.

Scratch Builders who wish to fabricate their own parts may contact to receive the required supplemental plans documentation in the mail.

Sport Acro Ailerons are intended to increase Sonex or Waiex roll rate for added fun and aerobatic capability. The standard Sonex or Waiex aileron provides a roll rate of approximately 80 degrees per second. Very preliminary test flight video footage has shown that Sport Acro Ailerons provide at least 105 degrees per second of roll at 125 mph.

Sport Acro flight testing will continue to progress with air show and competition aerobatic pilot Bud Judy along with commercial and recreational aerobatic pilot Mike Hoy as the Spring flying season approaches. Both Bud and Mike’s initial impressions of the Sport Acro are very enthusiastic and we are excited to complete flight testing for Primary and Sportsman-class aerobatic competition maneuvers. “It has all the roll rate and power needed to fly Sportsman acro!” remarked three-time U.S. National Aerobatic Champion Bud Judy after his first flight of the Sport Acro.

Parts Required for Sport Acro Aileron/Flap Installation
Click on the Part Numbers or Descriptions below to order. You must be logged-in to the Sonex Web Store as a Sonex Aircraft plans owner to view this product category.
Part Number Description Qty
CCP-42 for Ailerons Avdel Cherry Blind Rivets 356 272
CCP-42 for Flaps Avdel Cherry Blind Rivets 278 300
SNX-W04-02 Aileron Rib 6 4
SNX-W04-03 Aileron Rib 6 4
SNX-W04-04 Aileron Drive Plate 2 2
SNX-W04-07 Counterbalance Plate 4 4
SNX-W04-08 Counterweight Lead 1 1
SNX-W04-10L Aileron Tip Rib-LH 1 1
SNX-W04-10R Aileron Tip Rib-RH 1 1
SNX-W06-02 Flap Rib 3 4

Flap Rib

3 4
SNX-W06-04 Flap Drive Plate 2 2
SNX-Z02-01 58” Universal Aileron Skin 2 2
SNX-Z02-02 72" Flap Skin 2 2

*Note that SNX-Z02-01 41” Aileron Skin stock has been discontinued in-favor of the new 58” Universal Aileron Skin. Discontinued 41” aileron stock will not be accepted back to the factory for credit toward Sport Acro Aileron upgrade.  We have also discontinued SNX-Z03-01 42” Rudder and 37” Elevator skin stock, in favor of SNX-Z03-01 48” Universal Control Surface Skin stock. This control stock is used on Waiex Ruddervators, Sonex Elevators and Rudders.

More Sport Acro "Competition Mods" to Come!

Test flights are being video recorded with on-board cameras and we hope to have some video posted to in the coming months. Also to be released in the coming months will be Sport Acro Competition Mods, which are likely to include accessories for enhanced inverted fuel and oil capability for the AeroVee Engine and AeroCarb, single pilot rudder pedals, a center “bucket” seat with increased accommodations for a parachute, and a Sport Acro “Big Stick” for improved aileron control leverage.

What is the Sonex Sport Acro?

Much like the Sonex Sport Trainer, the Sport Acro is a hybrid of features and option selections for the existing Sonex design, making it suitable for enhanced aerobatic performance, and offering an affordable entry-level aircraft for Primary and Sportsman class aerobatic competition.

The primary feature of the Sonex Sport Acro consists of new, increased-span ailerons. These larger ailerons are expected to increase the crisp Sonex roll rate to a competition-worthy level. Aside from enlarged ailerons, the Sport Acro is a Standard Gear Sonex with a single Center Stick, which is the basic Sonex Complete Airframe Kit configuration. The Sport Acro has a five-point seatbelt harness configured to allow the pilot to sit in the middle of the aircraft for positioning directly on the roll axis, with the added benefit of making the Sport Acro an exceptionally capacious single place aircraft.

Upholstery, instrumentation and installed optional equipment have been kept to a minimum in order to keep the aircraft as light as possible. Sonex Aircraft, LLC expects the Sport Acro to achieve aerobatic competition-class performance on just 80 hp, and the prototype Sport Acro has an AeroConversions AeroVee 2.0 80 hp engine under the cowl. Using an AeroVee engine and requiring a minimum of optional equipment, a pilot can build an aircraft for entry-level aerobatic competition for just $25,000 complete.

I thought the Sonex Waiex and Xenos were already aerobatic?

Sonex Aircraft already are exceptional aerobatic machines. With full aerobatic category G-loading of +6 and -3 G’s at 950 lbs max aerobatic gross weight (1050 lbs for the Xenos Motorglider) and with an above-average load factor margin built-in, Sonex Aircraft represent some of the most structurally-sound aircraft available in the kit aircraft market today. Many Sonex Aircraft customers enjoy the aerobatic capabilities of their existing aircraft around the world, every day. All models and configurations of Sonex Aircraft are also Sport Pilot eligible, and the Sonex Sport Acro will be a Sport Pilot legal competition-class aircraft.

Sport Acro ailerons are enlarged
for greater roll rate.

With shorter-span flaps, what is the Stall Speed of the Sport Acro?

Vfe stall speed (stall speed with full flaps deployed) of the Sonex and Waiex with Standard Ailerons and Flaps is 40 mph. Keep in mind that clean stall speed of the Sonex and Waiex (with no flaps deployed) is only 46 mph. Although Sport Acro flaps are shortened in span by 1 rib bay, they are still large and very effective surfaces. We've found Vfe stall speed to have only increased by 2 mph in the Sport Acro configuration: 42 mph.

Can I modify my existing Sonex or Waiex with Sport Acro ailerons?

Yes. See the information above under "Sport Acro Ailerons Available!"

How do I add the Sport Acro Aileron option to my new kit order?

There is no need to specify any option selection when ordering your Sonex or Waiex kit. All new Sonex and Waiex Complete Airframe Kits shipped after February 1, 2008 include SNX-Z02-01 58” Universal Aileron Skin* stock that may be trimmed appropriately to fit either traditional or Sport Acro aileron dimensions. Also included are all flap and aileron ribs required to perform either installation, along with all required documentation.

When will the "Competition Mods" mentioned above be available?

While we have completed the preliminary flight testing on the Sport Acro, it still has some rigorous testing left including flights scheduled with two competition Aerobatic Pilots. The release date of Sport Acro "Competition Mods" is entirely dependent on the completion date of the flight test/R&D program.

How will I find out when Sport Acro "Competition Mods" are going to be available so I can order them? Can you call/email me?

We will making three public announcements when future Sport Acro Mods are Available:

  1. Posted on the Home Page of
  2. Posted on all three Online Discussion Groups affected (sonextalk, sonexplans, and waiexplans).
  3. A Press Release to all major aviation news sources.

You can also subscribe to Sonex Aircraft and AeroConversions RSS feeds to have notices of new Sonex and AeroConversions developments sent directly to your RSS reader, web browser or email application!

Due to the large volume of customers we currently deal with and the number interested in this release, we do not offer any other alert service including individual phone calls and e-mails.

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