>Bob,
>
>Your web page on the use of fuses in place of breakers is right, I think.
Maybe.
>
>With your wide experience you tell to use fuses but we amateurs, with the
wisdom
>gained from looking at existing panels say "yeah, Bob, but..." Here are a
few
>yabuts.
>
>"It isn't done this way, breakers are the standard way."
>
Who's "standard" . . . where is is written? FAR21, 25, 43 all speak to
the use and maintenance of both fuses and breakers. How did breakers become
a "standard". They certainly became a custom as people found out how BAD
the little fuse holders are with the caps that drop on the floor and roll
all the way back to the baggage compartment. Breakers became a convenience.
No place in the FARs does it say that ANY fuses or breakers have to be
located in reach of the pilot. They DO say that fuses in reach of any
crew that powers "flight critical" circuits must be backed up with
50% spares. So tell me what systems on your proposed airplane are
"flight critical" meaning that failure of the device presents an
immediate hazard to flight?
>"I can't risk the lives of my loved ones on something different."
>
Explain the risk. Paint the scenario where reseting a breaker in flight
is going to bring some absolutely essential piece of equipment back on
line.
>"It is harder to replace a fuse in flight than to reset a breaker."
>
>
You betcha . . . that's why I don't bother to put them anywhere I might
even be tempted to fiddle with them in the air. Be a pilot in the air
and save being a mechanic until on the ground.
>"We should not use anything that is used on automobiles until it is proven
on
>airplanes"
You got it backwards. The stuff on current airplanes was certified in 1940-
1970 with precious few changes since then. Take a walk through the Service
Difficulty Reports on the net and see how often a "certified" piece of
equipment
fails. Of course it can be "overhauled" and yellow-tagged and put right
back
on an airplane . . . it's the same piece of 1960's technology that came off
in the first place . . . you have any confidence in that? On the other hand,
how often do you have problems with similar gizmos in your car? The
environment
under the hood of a modern automobile is just as punishing as under the cowl
of an airplane. There's temperature cycles, splash, sand, dust, ozone,
oil vapors . . . you name it. For myself, I've replaced one alternator
on one
of 7 cars owned over the past 12 years with a cumulative total of more than
4,000 hours operating time . . . As I write these words, B&C is doing a
booming business in STANDBY alternators out of his booth at the American
Bonanza Society show here in Wichita. He just told me on the phone about
how often people have alternator troubles in their airplanes. If I owned
a $40,000 automobile and had these kinds of troubles, I'd be all over the
dealer. Yet people fly around in $250,000 airplanes and put up with the most
rediculous problems because "fixing" the problem is too expensive . . . and
besides, the current system is "certified."
The majority of alternators, starters, fuel injection systems, ignition
systems on cars go to the junk yard still working after 100,000+ miles of
service. Airplane products and designs are "carved in stone" while
automobiles continue to evolve and become better and better values every
year. I'd put any modern automobile part on my airplane before I'd
opt for a part out of a salvaged C-172 . . . even the new ones right off
the assembly line.
>
>"What if I later want to sell my airplane - who'd buy it with fuses?"
>
Somebody who understands why you elected to use fuses instead of breakers
and why they're out of reach just like on your car. Check the threads
and articles out on our website for more info . . .
>
>"A few fuses aren't nearly as impressive as a panel full of switches."
>
Now there is an EXCELLENT reason for going to breakers. I had a client
a few years ago hire me to do a wirebook for his proposed BD-10J project.
It was a design goal to make this airplane "look as military as possible".
We ended up with 65+ breakers in the airplane for a total of $1300.00.
Personally, I'd rather use that money -AND- panel space for something
really useful like a second GPS receiver or perhaps a CD player.
Regards,
Bob . . .
AeroElectric Connection
////
(o o)
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