Subject: LYCOMING DEVELOPS MORE POWERFUL ENGINE

Lycoming has developed its most powerful normally aspirated
four-cylinder engine. Dubbed the IO-390-X, the
390-cubic-inch-displacement engine features fuel injection and

develops

210 hp. The engine is made of factory-new parts and has a 2,000-hour
TBO. It burns 11.1 gallons per hour at 65-percent power and weighs

308

pounds dry.

Is this 308 lbs dry including any accessories?
Paul what is the dry weight of the 13B?

The bare 13B is about 190 pounds. Add 45 pounds for Tracy's PSRU.
then you have a five pound rad and 2 gallons of antifreeze or 16 pounds.
Those are the major parts. Frequently aircraft engine weights are quoted
without starter and alternator. The Mazda starter is 7 pounds and I am
guessing
on the alternator at around 8 pounds. PL

I assume this 210 developed Hp is Max developed Hp?
With that many cubes the torque should be way up there. Any numbers on

that?

Royce

Interesting 136.5 HP at 66.6 pounds per hour .49 BSFC. Not all that

great.

In fact a rotary can do better.

Paul Lamar

Paul,

I have a few questions on calculating the BSFC and different HP numbers.

1) Does AVgas and MOgas have the same energy potential and weight?  I

know

desiel fuel has more potential energy but also weighs more and needs to

be

considered in the calculations.

2) Could you explain to a slow learner {:>) exactly what the octane

rating

means.  Not how to calculate it but what the fuel does. (i.e. compare

100

octane to 50 octane)

3) When comparing AVgas motors to MOgas engines, do we need to

compensate for

weight or octane?

Scott Moore
N-316RJ (Reserved)
juno@dog.com

Well you got me there.
I will let others more familiar with fuels answer those questions.
Usually diesel BSFC, when quoted, does not take in to consideration
the energy difference per pound as I recall.

The Mazda rotary seems to run equally well on 100 LL and auto fuel.
As I understand it 100 LL is harder on spark plugs and O2 sensors.

Paul Lamar

Ron Freier wrote:

Octane is kind of the measure of how explosive the gas is. 100 octane is
less explosive than 80 octane. In a high compression/ high temp engine, 100
octane is used to prevent preignition and detonation. The 80 octane might
ignight from the hot spots or high compression before the spark plug fires.
I guess they measure it someway related to that.
I don't know how they control it during manufacture.

Ron Freier

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