"RST Engineering" wrote:

I'd like a consensus opinion from the newsgroup denizens who use any
of the popular "fuel pricing" websites as to the one that they find
the most accurate. My personal favorite over the last few years has
been Airnav, but I'm willing to be persuaded that there is better.

Got to put my two cents worth in here. A few years ago (2002) I used Airnav
to plan our trip to Oshkosh from the northwest, with stops in Washington DC,
New York, and Macinac Island. My thought was to use mogas where possible.

We left home and flew to Pullman in eastern Washington for the first fillup.
When we were passing 25 mi. north of Helena, MT, the engine quit - vapor
locked. Contributing factors were the high temperature (85 F @ 9500'), the
(I suspect) old mogas I bought in Pullman, and my fuel system design, having
the electric pump forward of the firewall and no forward-facing air scoops
on the tank vents.

Fortunately things cooled off on the glide down and I was able to effect a
restart as I was about to enter downwind for a soybean field; which would
likely have totaled the plane and possibly us as well. We flew in to Helena
and replaced the mogas with 100 LL.

I have since corrected the design deficiencies but I can't do anything about
the weather (no matter what ALgore says). One thing I can do is be very
careful as to when and where I burn mogas. I will not buy it from a source
which is unknown to me. This lets out every strange airport. I will not use
mogas on hot days nor at high altitudes.

Mogas burns clean and costs a buck or so less. 100 LL tends to foul my plugs
and costs more. My engine will run with two or three fouled plugs. It won't
run at all if it vapor locks. I've told this tale before and have gotten
used to the inevitable flaming. I'm *not* recommending that anyone use any
particular fuel. Fill it up with Dilithium crystals if you like. I'll spend
the extra buck for avgas when I head out over the Rockies for OSH.

YMMV

Rich S.