Archie wrote:

Can't help it, I must address at least one of these a week.
Hard to believe in this technological era, people are so naive,
and narrow minded.
Archie

That's true.  Normal auto industry engine test make FAR Part 33 look

like

a

piker.  But I don't know what sort of additional test Lycoming, et al,

do.

Tedd

 Not likely any serious testing is done on these aircraft engines of late.
 After all, current testing is done by all who own them, then compiled
 and faults become AD's.
  Remember, these were designed generations ago, and have changed little,
 whereas automotive is constantly changing in quest of mileage,
 longevity, and performance.
 The conventional aircraft engines have no need to change, they have
 a captive audience that feels these are the only engines that will
 fly safely, and will continue to pay for antique parts.
 Heck, they still require a break-in, and we in the business know why.
 No need to go on, you know where I am coming from.
 Archie Frangoudis,
 Archie's Racing Service

The FAA is partially to blame for this. If any change at all is made in the
aircraft engine, and that includes material change, the engine must be 
re certified. Naturally this discourages development. 

On the other hand much of the work done on auto engines is to match 
the durability and life to the low duty cycle of the automotive
environment and cut the cost. On board computer control of the 
duty cycle is a modern glaring example. 

If the automotive companies developed an aircraft
piston engine from scratch there would be no doubt in my mind that 
it would look very much like an air cooled aircraft engine and be largely
made from the same materials. There have been few breakthroughs in strength 
to weight ratio of metals and in the ratio of heat rejected to the number 
of fins per inch in the past 50 years. 4130 and 4340 are still the preferred
materials for the ferrous parts.  I don't think liquid cooling is 
worth the trouble and extra installation cost and weight.

The rotary on the other hand is a whole new ball game.

BTW here are some auto fuel prices per US gallon in suburban So CA
low test 1.85
high test 2.00
diesel 2.20

Where is the diesel advantage? Don't know what JP4 is going for. 

Paul Lamar
 
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