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I'm no AP regarding providing info on engines but I do remember that the
H2AD engines inherently have valve and/or valve guide history problem. That
gives me the impression that they approach consideration for the "lemon
list" hence the reason for their bargain price.
Regards engine choice you might consider first what you want. Do you want
to build a traveling machine for one or two people with or without luggage?
The answer will lead you to a powerplant system optimal for your purpose.
Starting from this position you can better define a proper choice.
Given design and program constraints the money situation should follow.
This initial Lancair design is an optimum system but you can taylor it to
your specific use. Another factor to consider is do you have the short or
long motor mounts. If you have short mounts you might consider a left
front prop governer configuration. They are rare but available for rebuild.
If you want a smooth operation get a counterweighted engine. The 360 four
bangers are notoriously rough but a counterweighted system is a significant
improvement. If you want the smoothest operation add a three blade MT prop.
The three composite blades provide more thrust which equals improved
performance, better flywheel action, quieter and 20 lbs lighter than the
hartzell. The tradeoff compared to a two blade prop is probable less top
speed of from 0 to 5-7 knots, higher initial and maintenance costs. I
cannot verify this but other owners-builders I talk to indicate this.
The choice of a 320 vs a 360 engine presents another issue. Check out the
market value of the 320's vs the 360's in Trade-A-Plane. I think you will
find you will get a better return on your investment when you sell your
machine with the larger engine. What is the compromise. Minor weight
increase, increased fuel operation, higher initial cost. The benefits are,
higher resale value more than offsets the cost differences, higher
performance, higher speeds, higher useful load potential, and a more forward
CG assuming the same prop configuration. You cannot beat horsepower.
Horsepower rules.
You might consider hopping up a 320 from Lycon but consider the following;
will a 10.5 compression ratio engine properly perform on a no lead fuel
without detonation? I am under the impression from reading the literature
that 100LL will soon be history and the EPA desires to eliminate the other
additive from fuels which prevent detonation. Staying with the lower
compression ratio motors seems like a wise decision for the near term and
keeps your future options open. The perceived saved costs of reduced weight
via a 320 hop up may in fact be a very costly situation in the next couple
years.
The fuel consumption arguement of the 320 vs the 360. It is my
understanding that you can throttle back the 360 and run quieter with
better fuel economy in cruise compared to the 320. Check out the charts.
You also get better performance. The best of both worlds.
I personally wanted a smooth cross country traveling machine which the
lancair was originally designed. The final setup I choose was an O360-F1A6
adding a Lycon modified sump and Airflow Performance fuel injection. This
rare engine has a left front prop governer valve which improves cooling air
flow rearward, avoids conflicts in an already tight aft cowl situation; is
counterweighted which smooths the engine and both design additions move the
CG forward; and there are no apparent lemon characteristics to the motor.
The motor was totally rebuilt and I requested the shop to run it on the
stand for four hours to avoid the conflict of breaking in an engine as
compared to low power runs necessary for pre initial flight taxi runs etc.
This was done to prevent possible break-in problems such as ring chatter or
cylinder glazing both which lead to excessive oil consumption.
The results are in. The above combination is soooo smooooooth: .025
inches per second on vibration analysis which didn't need balancing, amazing
thrust off the runway, great climb performance and I am very satisfied with
the speed. It is the smoothest 360 four banger I have flown. At altitude I
can fly between 9.5 and 10.5 gallons per hour. The extra powerplant weight
is offset by the lighter prop and most important my wife is thrilled with
this machine as compared to spam cans and Cessnas.
In summary, consider your optimum use for the craft then design the
configuration to best meet your needs then find the money to accomplish it.
I had an older mentor, now deceased, who went through the purchase decision
of a 55 foot sailing sloop. I was struggleing between the RV and Lancair
vis-a-vis cost. He had two choices one a sleek, fast, higher cost, higher
maintence vessell as compared to a slower, fatter, less maintenance
intensive boat. He chose his dream boat and opted for the higher price. I
also opted for the ultimate with the caveat of "price is not important as
long as it is safe and the extra costs doesn't change my life plans." This
may be your only chance to build your dream plane so be careful of the
compromises you build in. Will you be happy with the result. If you feel
cheated now in your decision; you will definitely feel more cheated later
on.
Incidentally, the plane is serial number 170 which has the short motor
mounts but was still able to mount a 27ah boxed battery in the engine
compartment on the right side and blasted air into it. This significantly
moved the CG forward, kept the header tank and moved the Oil pump behind the
passenger seat and the MKII tail and outback gear are also installed. The
CGs are within design limits.
Go for your dream, hang the costs and pay attention to your wife would be my
recommendation.
Bob Smiley
rjsmiley@tscnet.com
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LML website: http://www.olsusa.com/Users/Mkaye/maillist.html
LML Builders' Bookstore: http://www.buildersbooks.com/lancair
Please send your photos and drawings to marvkaye@olsusa.com.
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