Several weeks ago I threw out a question asking for feedback on the Deluxe Fuel Caps available from Van's. I got a couple of responses, but the overall dearth of interest I took to mean that almost no-one has them. So ...now that I have the caps in my hot little hands, I thought I would throw out a PIREP for anyone searching for the answer to the same question in future. Straight out of the box the Deluxe Caps look nicer than the standards with a more polished appearance. The dimensions of both are the same with the exception of the diameter of the filler neck, which is less on the deluxe caps due to the locking mechanism. The flange on the deluxe caps has a curve machined into it, so there is no need for any flange bending. That being said, the curve is a little too tight to fit the RV-10 tank skins well, I would imagine it would fit the other model's tanks much better. Nothing a bit of Proseal can't fill in any case. The standard caps have no separate locking mechanism. They are held in with the seal, which is formed by squeezing an O-Ring, forcing it outwards against the filler neck. I have seen a number of people report fuel leaks from around this seal. The deluxe caps have a two stage mechanism. The lowering of the clip presses the O-Ring at the top of the cap down against the angled wall of the filler neck, forming a more positive seal. With the clip up (and seal released) the cap is still held in, though it is loose. The cap is released by turning the clip 45 degrees, at which point the caps easily lifts out (as opposed to the force required to pull out the standard cap). The deluxe caps also can come with a key lock which is hidden below the clip. Overall all I am very impressed with these caps and very glad I bought them. Besides the fact they are just better, I think the ability to lock them is valuable in this day and age (unfortunately). Yes, they cost significantly more than the standard caps, but compared to the amount of money we are sinking into these aircraft... | 
