Introduction

[reed99re]

New owner of Sonex 509
Hi All.When you're not so good at landing a Sonex, can be problematic and costly. It's a legacy model built in 2012, with a Corvair engine. Anyways, after some serious tribulation, it's at its new home at Columbia Gorge Regional, in Dallesport, WA. On the delivery flight the Enigma EFIS bit the dust, and Matt at MGL kindly sent me a loaner to get me home. with the new EFIS, I had no visibility of fuel level, so made shorter hops, but ultimately decided to measure the tank's volume and re-calibrate the fuel level sender. We have all been told that the tank holds 16 gallons, and maybe almost 17. Now my bird's a taildragger, so the filler neck is the tank's high point. Using a 1-gallon pipette from the feed store, and carefully removing and measuring fuel, I measured the tank's volume at a whopping 17.5 gallons! Knowing this, I don't get why one would cite 16 gallons as the tank's capacity. There's no unusable fuel. Sure, one wants to be conservative about this, etc. etc. but really? Does this depend on how tight the metal support straps are?
Hopefully there are lots of folks who have been in my shoes. I may cry out for help from time to time!
Tailwinds, all.
Reed

[DCASonex]

Rotary molded fuel tanks are like snowflakes, No two are alike. 17.5 gallons does seen high. I get about 16.5 gallons in my tail dragger with a custom anti-siphon vent that allows full filling with tail on the ground without loosing fuel in level position.

David A.

[pappas]

I could put 17 in my old legacy Waiex. My Waiex B will hold 21. Both taildraggers.