Posted Monday, July 6, 2009 @ 07:33 AM  

If you look at the "Maintenance"-section and look in the lower right corner you can scroll to previuos pages, on page two you find James Bavendam´s thread on Oregon seat cushions with some good tips.

On all 4´s/ Jörgen

Posted Friday, July 10, 2009 @ 02:20 PM  

I have 1" of medium firmness on the seat bottom with another layer of 1" soft firmness on top and the seat back is also 1" of Soft.

It turned out quit nice and compresses to about 1" when I sit on it.

I contoured the foam at the front to round and thin it behind the knee and made the stick cutout using just an ordinarly bread knife.

I sewed a dacron envelope snug around the foam to keep the 2 layers in place and joined to the backrest piece and made a removable cover that slips over the cushion envelope.

When it was complete I was rather surprised at how well it actually turned out since I have never made such a thing before.

You simply sew the final cover inside out and snug on the foam envelope and when you are done you
turn it right side out and slip it over the cushion and viola, you have a nice looking and very comforatable seat cushion with a removable cover for washing and changing styles etc.

The project took about 4 hours with most of the time taking measurements and marking up the fabric with lines so I could sew it straight.

It was quite easy and using just a regular sewing machine, although the foam was expensive at $75 USD including shipping.

Previously I got a sore butt after about 1.5 hours in the air, but my last flight of 3 hours and I felt no discomfort what so ever and as a matter of fact I noticed that turbulence was also more comfortable with the belts and shoulder straps tightened down.

Total cost $90 USD for an extremely comfortable custom seat cushion for my Grob 109.

Ray

Posted Saturday, July 11, 2009 @ 11:14 AM  

Welcome to the Fournier family.

Oregon Aero cushions are great, but they are just an expensive way of packaging dynafoam/conforfoam, which is brilliant stuff, not just for superior comfort, but for excellent safety, because in a severe vertical impact (wheel-up landing) it only compresses slowly and absorbs the impact, rather than your spine absorbing it. Ordinary foams are dreadful in this regard, because they bounce-back and do even more spinal damage. Yes, confor/dyna foam is expensive, but what price the ability to continue walking?

You can get this foam in slabs from Aircraft Spruce & Specialty in one-inch, two-inch and three-inch thicknesses.

Matthew and I have been experimenting. We have taken out the moulded seatbacks from both our red one and my blue one and replaced them with a sheet of half-inch ply, cut to shape by tracing around the original seat back.
This gives you a more reclined seating position and frees up a useful storage area for heavy luggage, smoke canisters, oil bottles, battery etc behind the new seat back.

On the seat squab (the bit you sit on) I am currently using come of Spruce's three-inch, three-layer foam. Pink goes up (think pink bum to pink cushion). Matthew uses only two layers, two inches thick, medium & soft.

The Spruce blocks are, from memory, 18 inches by 20 inches. Saw off the excess few inches from the long length with a serrated bread knife, then use it as a lumbar support. Behind me I have, like Ray, a sheet of one-inch medium and a sheet of one-inch soft. Then we have used blocks and offcuts of this foam to provide adequate lumbar support. We started with rolled up towels and improved step by step.

After sitting on your new foam, don't immediately close the canopy, wiat for the foam to 'melt' around your shape and squash down. It squashes nearly two inches after five minutes.

Another tip. This foam easily splits and cracks if you bend it or pull it lengthwise, like pushing your bum rearwards on the cushion, so make covers soon. I do not know whether this foam is fire-resistant or non-flammable, but it is a good idea to make all your covers from wool or cotton (or leather if you're wealthy) -- fire retardant and slow-burning, rather than nasty man-made fibers, which burn fast and furiously while emitting arsenic and other highly toxic smokes.

That's why the informed pilot never wears clothes of man-made fibres. In a fire they melt and fuse into your skin making awful scars. Cotton, leather and wool only for this pilot -- plus they're more comfortable.

Enjoy your new foam, you'll find it is far more comfortable than 'ordinary' foam, and worth every cent. Also it doesn't compress under G, so your seat-belt does not go slack during aerobatics -- a nice touch.