February 2004 – nothing much left to do now. Some under-wing decals, final rigging, gap covers, some carby tuning, full throttle engine run and it’s ready to fly.


I had the registration number decals made by a fellow aviator who has a business making them. He helped greatly with advice on design and layout. I put them on wet as suggested and it worked out fine. It was so hot in the shed I don’t know whether the decals or me were dripping the most.


There was nobody else out there in the heat so I had to rig by myself. It is possible with cushions and stands but it takes a while running back and forth straightening and moving until it is set up.

Main pins

After one wing is in place through the fuselage spar box, the end wing pin is pushed half way through. When both wings and the both pins are in place, this is the last to be pushed home.

The other wing

With one wing secure, the other slides in the same way. The rear spar pins go in, then both main pins. For the right hand side I made a tapered rigging pin, which went in first and the main bolt followed, driving the rigging pin out the other side. There is no room on the left side so this needs some careful alignment before it will go in. Finally the aileron and flap pushrods are positioned and the bolts go in.

Gap covers

I had made the gap covers some time back but it is only now that they are riveted in place. I took the trouble to fit rubber channel all the way round so they sealed against the fuselage skin.

All rigged

Apart from prop, cowling and canopy all is done. It’s starting to look like an airplane. I will leave the gear leg fairings and wheel pants off until after the initial test flights.

Engine run

With canopy off because of the heat, I pulled it out and tested the engine. It took a bit of trial and error to get the needle of the Aerocarb set and give me the mixture I wanted, slightly rich. Then I gave the engine a brief run at high throttle. Not too much ground running to avoid high engine temperatures. Everything went well and I was happy that the engine and fuel delivery system was OK. Flying time real soon.

The next page in Lynn Jarvis’s Sonex project features The first flight.

Lynn Jarvis’s Sonex project

  |  1. Introduction  |  2. Sonex specifications  |  3. Building the Sonex  |

  |  4. The tail and spar  |  5. The wing  |  6. The aft fuselage  |  7. More on the fuselage  |

  |  8. It all comes together  | 9. The canopy  |  10. The engine  |  11. Electrical  |  12. The cowling  |

  |  13. Paint and polish  | 14. Moving  |  15. Finishing  |  16. First flight  |  17. Natfly 2004  |