So many questions from Rick.
I cannot address ES or Continental specific questions as I am
unfamiliar with both.
There are many pounds of weight that can be saved firewall forward.
Lycomings are generally considered heavier then Continentals because
the bare engine is heavier, yet my installation weight (twin turbo,
dual intercoolers, automatic waste gate, dual alternator, oil) measured
out at 611 lbs, 13 lbs lighter that a comparable TSIO 550 configuration.
Replacing the AN365 nuts and AN960 washers with MS21042 nuts and
AN960PD (aluminum) washers saves several pounds. Replacing the AN steel
bolts with NAS-640x titanium bolts saves even more. Removing
unnecessary (to flight) lifting brackets saves weight. Replacing heavy
rubber flex hoses with stainless or aluminum hard line with aluminum B
nuts saves a lot of weight. If you are really warped (like me) you will
make titanium seal belt attachments and buckles and titanium door
hinges.
Don't get too carried away. Don't use aluminum AN fittings on the
engine. Don't use hard line where a flex line is required. Don't use
aluminum washers near the exhaust system.
The most common electrical installed item to fail is the keyed ignition
switch. I used the Nuckolls' approach with two 3 position magneto
switches and a starter button. There is also a hidden switch that
disables the starter for security. I don't recall ever seeing a jet
that uses a key to start the engines. If thieves are determined enough
to get past the door lock, an aircraft ignition switch is a trivial
nuisance.
Some answers to Rick's questions below. Circuit List posted on a
separate email.
<<<<
Since a IV
is theoretically similar to an
ES electrically, I am very interested in your electrical
system/suggestions -
can you post/send a schematic?
Circuit List posted. A schematic only shows
interconnections, not the implementation details which are frequently
as, or more, significant.
Do you have
a single/common ground
bus? Any special
precautions with it (as a single point of
failure)?
Yes, at the firewall penetration. It is a 3/8" brass bar with a copper
plate that has 60 ground screws.
<>
How is your backup alternator and battery
connected to the ships electrical systems? Through the cross-tie? Only?
Diode and cross tie.
Is your
backup alternator a B&C
SD-20? Or equivalent?
Yes.
Have you
segregated your
“essential” electrical equipment (i.e. a separate E-bus) to
easily/effortlessly configure your system for low power draw (aka <
20 amps)
in the event of a primary alternator (or regulator) failure?
Yes.
How do you
turn on the essential bus
and/or turn off everything else?
Essential Bus switch ON, Main Buss switch OFF
Are there
any single points of failure in
the essential bus and/or it’s feed(s)?
Only the ground penetration mentioned above.
What
equipment is on your essential bus
(if you have one)?
See Circuit list posted separately.
What is your
essential bus maximum current
draw?
9.54 Amps (measured)
What is your
overall maximum current draw
(everything on)?
63.75 Amps (measured) includes HPU and Door Seal Pump
Do you have
seat heaters? Front and back?
No. Seat heaters, CD players, air conditioning,
etc. are luxury items that deal with occasional / transient discomforts
yet they must be carried all the time. I would rather have the luxury
of going faster, something I enjoy every flight all the time.
What is your
typical continuous draw (with
most normal/continuous things on – like pitot heat, lights, etc.
See Circuit list.
<>What
is your strategy/timing for replacing
your batteries (every 2-3 years)?
Yes,
on time.
Do you have
a load based AH battery
test apparatus/procedure?
<> No.
Better to replace on time. There are failure modes a load test won't
discover.
When
starting, do you typically have other
electrical equipment on? EFIS? Engine Mon? GPS?
Beakon? Cabin/Panel Lights?
Yes, everything (Main Buss) on.
Have you
every had a starting brownout
and/or starting spike failure?
No.
Do you
believe in them?
<>Yes, I believe some equipment is sensitive to brown outs and some
electrical systems are poorly designed. I did not select sensitive
equipment and have a 28V system with low impedance connections to the
battery. Also the system is implemented such that the IR losses (amps
times resistance = voltage drop) during starting are contained in the
starting circuit and not reflected in the Main Buss (other than the
battery internal resistance and terminal resistances). I designed full
clamping battery terminal terminations to reduce losses.
Have you
ever had issues trying to start
with a very cold battery (i.e. -10F)?
No, Started fine at -15F in Denver. B&C Starter.
What compression is your engine?
8.5:1. Yes it is turbocharged. Maximum manifold pressure
at 2,700 RPM is 35 In Hg, producing 360 Hp (SAE corrected) on Monty
Barrett's dyno.
>>>>>>>
Regards
Brent Regan
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