"Jerry Springer" wrote in message
Better way? New design yes... auto engines no. Sorry I have not been
flying quite as long as Barnyard, only about 40 years for me. BUT every
auto engine conversion I know of has had a failure of some type.

But look at the bright side: With this one, if the SeaBee engine fails,
you get to shoot the dead-stick landing in air-conditioned comfort. :-)

On Mon, 20 Oct 2003 20:22:17 -0700, "Bart D. Hull"
wrote:

I can buy the third issue. But what if it was a FADEC on a
Cont or a LYC instead? They quit without juice as well.

But Continental and Lycoming had to convince a *very* skeptical FAA about
the reliability of the FADEC. They had to prove that the FADEC is at least
as reliable as two magnetos.

I remember an article, years ago, about what Porsche had to do to certify
the PFM engine for the Mooney. They had to prove the two independent
ignition systems *were* completely independent. I think they even had to
apply a sudden dead short across one, just to prove the other one would
keep running.

I'm not being argumentative, but want more details so my
auto-conversion will be more successful than a LYC or Cont
install.

A good goal, and worthy of discussion. With one exception, the failures I
hear about have been fairly random, mostly related to the subsystems rather
than the core engine.

I think the lesson would be to strive for maximum redundancy. There
*should* be two completely independent ignition systems. Two batteries,
two electronics boxes, two sets of plug wires, two plugs per cylinder. The
second should be solely a backup, connected to *nothing* in common with the
primary system. If the primary system uses the distributor drive to time
the ignition, the backup system should run off a hall effect sensor on the
flywheel.

Buy a drycell battery and run it directly to the backup ignition
electronics...no connection to the primary bus. I say a drycell simply
because of their ability to hold a charge a long time. Test the ignition
momentarily during runup and slap a charger on the backup system every week
or so.

That way if your electrical system goes to hellandgone, you've got a
completely independent backup. The drycell should be sized to give you at
least a half-hour of flight time...I'm basing that on the required VFR fuel
reserve.

Probably your biggest worry, compared to a Lycosaur, is cooling. The air
cooling of your classic aircraft engine is extremely reliable...if it cools
properly when it's initially installed, there's very little that can happen
to it to make it NOT cool. If the oil cooler quits working, the engine
probably will last long enough to get you to a runway (other than if it
spews oil everywhere, of course).

You're not going to match that level of reliability; your airplane will
have a water pump, water hoses, and radiator that the Lycosaur lacks and
thus can't stop running if they quit. The lesson here is probably to use
the best quality parts you can find (race-type hoses, etc.) and to oversize
the system... if you develop a coolant leak in flight, it's nice if your
plane has to lose five gallons of coolant before it starts to overheat
rather than five quarts. Gauge the heck out of it, too...you want to be
able to detect problems as early as possible. I'd try put together some
sort of annunciator system rather than depend on the pilot's eyes to catch
a fading gauge.

I wonder what could be done along the lines of emergency cooling, like the
emergency ignition? The AVweb article about flying the Hawker Hurricane
makes me wonder about a spray-bar system for auto-engine conversions.
Could you gain some flying time if you had a system that would spray the
engine itself with water? And/Or some emergency cowl flaps that would open
and expose the engine case directly to the slipstream?

The PSRU is another single point failure item. I don't know what one could
do to increase redundancy, but plenty of design margin would be a good
start. Regular, in-depth inspections would be another...guy across from me
just found a crack in one plate of his gyro's PSRU.

Years ago, Kit Sondergren had an article in KITPLANES about terminating the
A-65 engine on his Mustang. He decided it needed to get overhauled, so he
tried a little experiment...he drained out all the oil and ran it on the
ground. IIRC, that engine ran at moderate throttle for something like a
half-hour before it really started to labor. I *like* that in an aircraft
engine. Nothing for cooling but the slipstream, two independent ignition
systems that generate their own power, and a engine that'll run for a
fairly long while with no oil at all. Lycomings and Continentals have one
thing in common with the dinosaurs: They leave mighty big shoes
to fill. :-)

I'm cautious about auto-engine conversions, but I wholly support those who
want to experiment with them. I like your attitude about wanting more
details to help improve your own work. Please continue to plug yourself
into information sources to build the safest engine possible.

Ron Wanttaja