| Principles
and myths of instrument panel design
by Bob Collins
Exploding
myths and issuing fair warnings was the task of a panel of experts
when the topic was panels.
 |
| Doug Weiler
displays a view of the instrument panel he designed for his
RV-4. |
It's not easy
to confuse an RV with a Boeing 757. But maybe as he patrols the
RV area at Oshkosh next month, Doug Weiler of Hudson, Wisc., will
have to remind himself that he's not sitting in the cockpit of
the 757 he flies for a living for Northwest Airlines. Glass cockpit
fever has gripped the homebuilt market.
Doug heads
the Minnesota
Wing of Van's Air Force, and presided Saturday (June 17, 2006)
over the group's quarterly meeting at the headquarters of Stein
Air in Farmington, Minn. He was one of three experts in RV building
to present a program on instrument panels.
When he flies
airplanes for fun, he sits in an RV-4, an airplane he built three
years ago that's "already an antique," he says, referring
to his instrument panel. When he built his RV, he says instrument
panels in RVs were still "very haphazard. There were no human
factors considered and stuff was spread out all over the panel.
It didn't make any sense."
"The
757 I work with is not a new airplane; it's not a complex airplane
either in terms of what's possible in our homebuilts. Moving maps
'just the basics.' But you can really go overboard on this and
have too much technology available. In the airline business you
don't need a lot of information," he says, noting that airlines
travel on a pretty pre-determined path.
Weiler spent
a lot of time, he says, sitting in the airplane "deciding
where I was going to place things." Then he brought up that
phrase again -- "human factors." He thought long and
hard about the processes of, for example, starting the engine,
and putting the flaps down. Pushing switches and flipping buttons.
Part of it is because of the small amount of space in an RV-4
panel. But even in side-by-side RVs, the panel -- the one talking
about panels -- agreed that organizing things by considering the
human factors is one of the first things that needs to be done
by any homebuilder of any aircraft.
Still, there
isn't always just one way to do it. "When you go to Oshkosh
and see all the RVs on the line, what makes you go to look at
one airplane? Usually it's the paint job. The next thing is the
instrument panel. So the two are personal things. We have a rule
in the airline biz: when you're flying along for hours at a time,
you don't discuss religion, politics, instrument panels or paint
jobs because everyone has a different opinion of them," he
says.
"My philosophy
is if you look at what Cessna or Cirrus has done, they've done
it for a reason, and they figured out pretty closely why they
did do that.
 |
| Tom
Berge presented several slides of panels to show some of his
design traits. One thing he doesn't like is the stock control
panel from Van's, especially the plate that fits below it
to hold the various engine controls because it's a "knife
edge." |
Tom Berge,
of Plymouth, Minnesota, has noticed the same thing and he's built
about a half-dozen instrument panels to prove it. He now owns
and RV-7A, but built an RV-6A before. "All of my panels have
been steam gauges; the RV 6 was all steam gauge."
"I put
everything as tight as I can. At Oshkosh I see lots of people
who , because they have real estate on the panel, they try to
space it across the panel. The problem is the next year you go
to Oshkosh, you find new instruments to put in, but there's no
room," he says. That's why Berge is meticulous about making
sure there's plenty of room. How? On his latest panel, he designed
everything down to 20-thousands of an inch.
Berge then
presented several slides of panels to show some of his design
traits. One thing he doesn't like is the stock control panel from
Van's, especially the plate that fits below it to hold the various
engine controls because it's a "knife edge." So he creates
his own panels and adds to the height -- or more accurately, the
lower dimension -- of the panel to create more room and remove
what he thinks is an unseemly element of the Van's design.
He notes that
he's "buried" his fuses and has no access to them while
flying. "If something blows, while flying, what am I going
to do anyway?" Berge notes.
He likes to
keep things symmetrical. "Keep it in tight" is his motto
and think about what's going on behind the panel. For example,
he builds in a 1/4" gap in the radio stack (they're not flush
with the panel) to assist in their cooling.
Berge's is
a tip-up canopy, something he says is easier to work on because
you have access to the subpanel. But the tip-up does have a "rain
situation," he says. Along the top (bow) of the panel, he's
cut 3/4" foam and placed it along the channel, but he says
around the left side of the canopy frame brace strut, it's not
uncommon to get leakage when flying in the rain.
He started
laying out his panel four years ago and started building it three-and-half
years ago. The boxes were still expensive. If I were to do it
again, I'd do glass. The thing that will limit you is what the
airplane is capable of doing.
Those are
the kind of situations that Stein Bruch of SteinAir,
Inc., of Farmington, Minnesota. The rapidly-growing firm builds
instrument panels and provides avionics services to homebuilders.
 |
| Homebuilders make a lot of mistakes when starting to
design their panel, and he's got the now-useless panels to
prove it. |
"For
the most part we do EFIS panels now," he says. "We've
done several steam gauge panels, but my RV-6 is all round gauges.
People ask me why I don't fly behind what I build and I tell them
if anyone wants to buy me a Chelton, I'll be happy to fly behind
it."
Bruch recently
wrote an article for EAA's Sport Aviation (May 2006 issue-
EAA membership required) on the mistakes homebuilders make when
designing -- and cutting --their panels. He had a stack of no-longer-usable
panels that people sent him to prove it.
He says customers
make a mistake when the first thing they decide is what "goodies"
they want to put in the panel."Don't pick the goodies first
and design the panel around that. The first thing you should do
is look at what kind of flying do you do? If you treat it like
a Champ, there's no reason to buy it all. If you fly IFR, you
better think about redundancy and the human factors involved,"
he cautions.
There's that
phrase again -- human factors. "I argue with folks all the
time. Your hand is on the throttle and you want to reach all the
way over there to turn the key on the starter? I had a customer
call last week who I'd argued with but who insisted on putting
the key way on the other side of the panel. Now he calls last
week and says, 'you know what? That was a stupid idea.' 'Well,
no (kidding), I told you that,' he said.
Like Berge,
Bruch also finds the need to think -- a lot -- about space. He
says a recent customer sent him a panel that didn't have enough
room between instruments."You have to be a minimum of 1/8"
apart for the little instruments, 1/4" for the large ones;
sometimes more," according to Bruch. "People cut their
panels for 6 1/4" wide for 6 1/4"-wide radios, but they
forget you have to install angle for the radio tray. So sometimes
they cut the instrument holes so close to each other that you
can't mount the radio trays."
And it's not
just instruments. Sometimes get breakers and other switches so
close together that in order to take one out, "you have to
take them all out." Also like Berge, Bruch doesn't use Van's
stock panels anymore, preferring to custom build each from a flat
sheet of aluminum. Even that, however, is not without its potential
for mistakes for those who choose to go that route. Be careful
of the dimensions and the drawings. A tip-up and slider is not
the same panel. "The bow across the top is different. I blew
$150 on that mistake," he says.
Mistakes are
costly when building costly panels. He figures the average panel
he's building at Stein Air is made up of $60,000-$65,000 in components,
with an RV-10 pinning the dial at $125,000 recently. If you're
sending it out to a third party, figure on an additional 15% for
the labor.
Bruch also
explodes a growing myth in avionics; the one that says 'don't
order your avionics until the very last minute because they're
changing so fast.' And here he has some warnings for shoppers
at Oshkosh, and harsh words for a few vendors too. "What
you get at Oshkosh this year, you won't get in your hands until
next year," he says. At Sun 'n Fun he says he heard vendors
tell customers their products will ship in about 5 or 6 weeks.
"We're just now getting stuff we ordered in February. And
I say to the vendors, 'why are you telling people it's going to
be 5 or 6 weeks?' And they say, 'we're gonna catch up.'"
Bruch recommends
start buying avionics at least 6 months before you intend to start
flying, or else your fly-ready airplane will be sitting on the
ground waiting for something to fill the instrument panel. "At
Oshkosh, people sell stuff that isn't even available," he
says. "It's disgusting."
In a timely
display of consumer protection, Stein ran through several examples
of why buyers have to be very careful when selecting products.
Many glass systems are display only, and the consumer assumes
that changing the radio frequencies (VOR, for example) changes
the display. But that's not always the case, he notes. "And
none of them will tell you that," according to Bruch.
 |
| Eyes
front...and up...and left...and right, but not necessarily
down. Something to remember for after you build your instrument
panel, reminds Tom Irlbeck. |
He recommends
those IFR pilots looking for redundancy avoid using the same company's
products across the panel. "Most of the time the EFIS systems
are tied together," he says, " and when systems crash,
it's usually not a hardware problem; it's a software problem"
and if the same company is used for the backup, the problem is
likely to take down the redundant element too.
At most Minnesota
RV Builders meetings, the final word is usually left to Tom Irlbeck,
a former top-gun Navy pilot, multiple RV builder and flier and
CFI. "Once you're 10 miles from the airport," he says,
you should only be looking out at the window, not adjusting glass
cockpit screens and flip-flops."
In the
end, the instrument on either side of your nose is the most valuable.
More Photos
Tom Berge shows the
area around a tip-up that is prone to leakage when flying in the
rain. It's the left side just above and slightly to the right
of the attitude indicator on this panel.
Lighting on
an instrument panel is becoming less of an issue, notes Stein
Bruch, now that more manufacturers are including internal lighting
in their products.
A look at
one of several SteinAir workbenches.
If your name
is here, man, are you lucky to have these goodies.
Other
information:
RV Builder's
Hotline (3/25/06): Where dreams meet metal
Instrument
panel photos on RV Builders Group on Yahoo
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