Improved+Lumbar+Support

If you have done any long flights in your Sonex you will have noticed that the seat which initially feels quite comfortable can become extremely uncomfortable because it is really just an aluminium camp chair. There is no lumbar support. Look at the seats in any reasonably modern car and it's easy to pick the difference. I drive a 10-year-old Ford Focus, about as white bread as you can get, but I have done a couple of 9-hour trips and even one 18-hour trip with only stops to refuel and refood, all in reasonable comfort, but more than 2 hours in the Sonex can be agonising. It's not a matter of seat padding. The problem is lack of lower back support. Here's a very low-cost lightweight solution. I bought a couple of these mesh back supports for around $3 to $4 each from a junk shop and have seen similar things on eBay for as low as $3.79. I now fly with one all the time and find them surprisingly effective. It is possible (just) to fit two of them side-by-side so that your passenger can have a bit of comfort too.

Update
Since writing the above article I have made what I think is a further and more permanent improvement to the seat back in my Sonex. This was prompted by a trip I did last year when I flew up to 7 hours in a day. I felt OK at the time but my back was a bit stiff later. This is a carved polystyrene foam seat former that slips behind the existing foam rubber seat back cushion. The shape is a rough copy of the seat in my car. I have only made one so far but I'm intending to make a matching one for my passenger.

The material is 30 mm blue polystyrene foam. The back is 353 mm wide by 400 mm high. Maximum thickness of 30 mm is located 150 mm from the bottom edge and it tapers to about 2 mm at the top and bottom. The sides are carved from the same 30 mm sheet. The maximum side depth of 70 mm is located about 180 mm from the bottom. It just slips in behind the existing seat-back cushion which in my case is 50 mm foam rubber. I think the seat cushion should be thinner now but this was just a try-out. The first time I used it was for my trip to the Old Station fly-in. On that trip I flew up to nearly 6 hours in a day. It felt comfortable from start to finish.

Peter Anson Sonex 894