Cooper Aircraft Corporation

05/08/2026

Sonex is back in action!

04/07/2026

We have been fortunate to play a small role in this planes construction. Great to see it all together and getting close to final assembly!

04/03/2026

We wanted to address the elephant in the room as this week comes to a close.

Working with Sonex owners has been a significant part of our business. The recent announcement of Sonex closing its doors has been a truly heartbreaking moment for us as well as many of you. Mark and the crew at Sonex are among some of the most knowledgeable, hardest working, and kind people we have had the pleasure of working with. It’s been wonderful becoming friends while diving into this small community of homebuilders and aviators. We’re certain Sonex will carry on. There’s too much love in the community and too many aircraft to just watch them go away. As Sonex always said, they have the best performance per dollar, which is very true.

We have seen tragedy in the Sonex family before and they’ve overcome. We’re certain Sonex will again.

That being said, we are going to continue to support the Sonex fleet the best we can. While we do mostly firewall forward and builder support, we will be actively trying to assist the community in aspects generally out of our “area”. We deeply appreciate customers reaching out and the overwhelming willingness to work together. We will be getting back to everyone shortly (calls, emails, etc) as we find our footing during these times.

We’re looking forward talking with everyone and just carrying on a great thing. We genuinely appreciate your patience and support.

03/11/2026

02/22/2026

We thought this was really cool.

We sent out a package of 2 installation kits to a married couple this week. They building 2 Onex’s side by side, his and hers, with Rotax 912iS’s. What better way to spend time with your significant other than building a couple airplanes together!

We wish you the best in your endeavors with your builds and we’re excited to see your progress!

02/11/2026

02/01/2026

We have been going through an engine lately for one of our customers. It just recently rolled over 2,000 hours and needed a little freshen up. While we did not overhaul this engine, we did clean it up a bit, reseal it, a rubber change, and general inspection. Even after that all that time, it’s very healthy with all compressions within a couple pounds of new.

With it we are sending one of our suspension mount kits, one of our carbon spinners, and some other goodies which will go into a Sonex Onex 🚀

01/20/2026

While waiting on parts for other projects, we began covering this JN-4 Jenny replica. Some rib stitching, finishing tapes, and this wing is ready for some primer. Then onto the top wing.

The Jenny began production in the 1910’s. This particular one will be powered by a Rotax 912ULS. Nostalgic look with modern life support! This one will be at Airventure 2026 😎

01/16/2026

More sheet metal madness with Bryan!

11/19/2025

A little highlight today on the Rotax 912ULS Onex project!

Numbers from 5,200 rpm (economy cruise)
- Cylinder head temperature 174 degrees
- Oil temperature 171 degrees
- 160-165 mph cruise indicated, 170-175 mph true airspeed

Numbers from 4,800 rpm (super economy cruise)
- Cylinder head temperature 173 degrees
- Oil temperature 158 degrees 
- 145 mph cruise indicated, 155 mph true airspeed

1,300-1,400 feet per minute sustained at 100 mph

60 outside air temperature

Engine runs a little cooler than we’d like but very happy! It’s great to see these numbers!