Rick Maddy wrote:

1) Fuel - Can the XP-360 use autogas? Can the listed auto engines use
100LL? For those of you using an auto engine - how do you get autogas
to your plane?

Since the engine is going into an experimental, you have the option of
de-certifying what would otherwise be considered a "certified" engine.
Many of the certified engines can be run on autogas, even when the
certified engine in a certified airframe cannot. Running on autogas can
significantly impact your hourly run rate, so this is an important thing
to get nailed down if you want to go with a Lycoming or Continental.

Auto engines can burn 100LL. The issue is (primarily) the posioning of
the oxygen sensor (O2 sensor). Some auto conversions retain the O2 sensor
while others do not. Since you said you don't know squat about engines,
I'll assume you're going to try to get a firewall forward package. Ask
the packager if 100LL is an issue.

As for getting autogas to the plane: some airports have autogas (check
your A/FD). Some people transport fuel to the plane in gas cans, and a
few hardy souls have crafted tankers to cart fuel to the plane. See Jay
Honeck's "Mighty Grape" in this forum (search Google Newsgroups) or Jim
Weir's fine 54 gallon fuel trailer plans in Kitplanes magazine (IIRC).


XP-360

Pros: Fairly standard, mostly plans install. Improvement over true
Lycoming. Get repairs at most airports. Get 100LL any airport.
Cons: Expensive repairs.

Auto Engine

Pros: Newer technology. Much cheaper repair. Cheaper parts at local
auto parts store.
Cons: Smaller knowledge base. Huge deviation from plans install. Might
need custom cowling. Where to get repairs? Where to get gas?

If you go the auto conversion route, you are almost 100% certain to use a
water-cooled engine. This is always problematic since the airframe
designer almost never plans for radiators. And cooling on canards (like
the Cozy you're building) is a dicey proposition. You're opening a big
can of worms. Think long and hard about copying some other Cozy builder's
*successful* auto conversion.

Comparisons that I see as a wash:

- Initial installation costs will end up being about the same.

Not really. Out-of-pocket expense for a new turnkey certified engine will
be somewhat higher than those for a turnkey auto conversion, but the cost
in time spent re-engineering things to fit your airframe will be much
higher for the auto conversion. And the certified engine installation
will be alot more deterministic (less guessing and experimenting). What's
your time worth?

- Installed weight/CG will be about the same.

If you're lucky/careful. If you're sloppy, the auto conversion will weigh
a ton. Beware.

- I know nothing about either so I have the same amount to learn.

There's not much to learn (societally, not individually) about putting a
Lycoming or Continental in a Cozy: scores of builders have done it before
and the trail is well marked. Choose a Jaibiru, 13B, Chevy, Ford, or
Subaru and suddenly you're one of maybe a dozen (or less). Choose a
Renesis and you'll be the trailblazer (although you could probably copy
alot from a 13B).

Russell Kent