The market for glider instruments is small and fractious, the customers at once
demanding and frugal, and the competition fierce. Against this backdrop it’s reasonable
to ask if there is room or need for yet another company. Here’s the answer from ClearNav
Instruments.
Company History
I am hardly the first glider pilot to get frustrated
about the limitations of computers in the glider
cockpit, but as an owner of the NielsenKellerman company which designed and
manufactured electronic products (weather
instruments for a wide range of markets, and
performance monitors for the sport of rowing) I
found myself in a position to do something
about it.
Last November, and within three years of
shipping the first ClearNav, we chose to sell the
Nielsen-Kellerman Company and I purchased
the soaring business from my two partners and
renamed it ClearNav Instruments.
product and continues to contribute to the
vario project. John Good (Discus 2a) is
creating software for the vario, and Frank
Paynter (Ventus 2bx) has provided both
software and user interface design expertise
to ClearNav and the vario.
Two other team members, Phil Schlosser and
Angus Raby, provide hardware skills. The
company has one full-time employee: Gary
Kammerer who builds each and every
ClearNav and provides support for US
customers in addition to support for the
Cambridge Aero LNAV / SNAV / GPSNAV
products.
Who are we ?
Tim Welles (Ventus 2cx) and I (ASG-29) now
own ClearNav Instruments. Tim manages the
ClearNav product, I manage the variometer
project, as well as handling all mechanical
engineering tasks.
Chip Garner (Discus 2a) wrote the code for
ClearNav and contributed many of the design
features. Dave Ellis (LS-4) helped with the
design of the ClearNav and has played a critical
role in the development of the vario. Rick
Sheppe (Silent 2) was responsible for a good
deal of the look and feel of the ClearNav
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Gliding International (November-December 2011)
Readers with an appreciation both for history
and continuity will have noticed that six
members of the CNI team were also involved
with Cambridge Aero, a nice segue to our
product design philosophy, which shares with
CAI a preoccupation with the need to provide
simple user interfaces.
Product Design and Business Philosophy
Our business model is based on the premise
that there is a market for instruments designed
for
the
glider
cockpit
environment,
notwithstanding the popularity of low cost
devices designed for much larger markets and
adapted for glider use. We recognize that
these devices, and their successors, are here
to stay and plan to make it as easy as possible
for third parties offering such products to make
use of variometry data.
Our design philosophy accepts as literal the
old joke about the IQ of the pilot decreasing by
a factor of two when the canopy is latched. We
design to keep the UI simple and intuitive, and
to the greatest extent possible limit the pilot’s
interaction with the products to looking and
listening - with the absolute minimum amount
of pushing, turning, clicking and pointing.
I’m running a ridge to the final turn area
which requires leaving the ridge for
several miles, nipping the area on what is
obviously a dying day, and getting back
onto the ridge for home. Same plan for
thirty plus other pilots. I can’t see the PDA
display with the low sun angle, can’t see
the other gliders too well either, and can’t
use the touch features of the PDA
because its just too rough. There and
then I decided there has to be a better
way.
instance, our vario will require no additional
power connections when used with ClearNav.
We chose to include a GPS engine in
accordance with our imperative to keep things
simple for the pilot. Adding a secure flight
recorder was not difficult once the GPS was in
place and represents good value for our users.
The screen capture (Page 1) gives a sense of
the range of data available without any need to
do any more than zoom in or out.
Everything on one screen – landing range,
task management, SUA and some of the
user-selectable flight data.
ClearNav Flight Computer
This was our first product, initially sold by the
Nielsen-Kellerman Co. The design of the
product was driven by a few fundamental
requirements: Full situational awareness
including the landability footprint, task
management, and SUA, a screen large
enough and bright enough to guarantee easy
readability under all conditions, and the
simplest possible UI with the minimum
requirements for user input. Technical
considerations included the choice of the
automotive industry standard data buss (CANbus) for data links between our products, a
serial port for support of third-party devices,
and a USB socket to facilitate in-field
software/firmware updates. The flat telephone
cable carrying the CAN messages also
provides power and ground so that, for
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GENESIS OF A PRODUCT
The jagged red and purple lines represent the
glide ranges with zero margin (purple) and with
a user-settable margin(red). Both lines take into
account terrain, wind, and the current polar.
The task turn areas are the two large black
circles. To eliminate the need to create and/or
move points we compute and display an arc
(blue line in the turn area centred on 16) any
point on which will give an equal distance to
the centre of the next turn area. The position
of this arc depends on achieved speed and
becomes particularly important in the final turn
area when it provides accurate guidance to
the pilot on when to turn for home. This
feature greatly simplifies the management of
area tasks.
Gliding International (November-December 2011)
WHY NO TOUCH SCREEN?
There are numerous advantages to a
touch screen as the Apple iPhone has
demonstrated. Not all of them transfer
well to the cockpit. Some panels are
quite hard to reach, it’s too easy to
touch the wrong point, especially when
in turbulent air, and the touch screen
itself reduces the visibility of the display.
That said, we are confident that we have
succeeded in our goal of simplifying the
UI to the point where there is little need
to do much more than zooming the
display. We do provide a “cursor” which
is a rectangle centred on the glider and
visible in both the screen shots – it’s
fast and easy to use this cursor and the
keypad controller to select or mark
point, and control SUA alarms etc.
The SUA around Roanoke, VA is clearly
depicted - but in the event that the pilot flies too
close - a hard-to-miss screen change plus an
audio alarm demands attention and gives the
pilot everything needed to stay out of the
airspace: Split screen SUA alarm – repeated
airspace infractions at the highest levels of
competition suggested that we needed to do
something different and more effective.
This scheme seems to work well. The screen
(Page 3 Lower Left) is zoomed in the SUA, the
lower is the prior scale and allows the pilot to
maintain situational awareness.
Clearnav Vario
Although ClearNav (the instrument) does not
need a vario, ClearNav, the company, does and we are now in the final stages of what has
proven to be a long development period. In
designing our vario we were guided by some
simple considerations:
Performance for the initial product release
at least equal to that of the CAI 302 vario,
full integration with the ClearNav flight
computer plus support for third party
devices and software, a full suite of
sensors as the basis for advanced
variometry,
in-cockpit
software
and
firmware updates, a high resolution
graphical
display
coupled
with
a
mechanical pointer, the simplest possible
UI and the inclusion of both a GPS engine
and a secure flight recorder.
We will offer the vario in one and only one
hardware configuration but with a wide range
of software enabled features, ranging from a
basic vario, with price and performance
attractive to the club and entry-level market, to
a full featured advanced vario.
Because all of the required hardware is always
present it’s a simple matter for the user to
purchase and install any additional feature.
We have chosen to split the vario into two
enclosures, the Air Data Computer (ADC)
which houses all of the sensors and the SFR,
and the display which houses the pointer, two
control encoders and the display.
The split packaging allows the ADC to be
mounted anywhere and makes it simple to
have multiple displays. It can also be mounted
to the back of the display.
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Gliding International (November-December 2011)
The display module (upper right) fits a 57mm
hole and it extends behind the panel by
40mm. It connects to the ADC (upper left) via
the power CAN-bus cable.
In addition to the pressure transducers
required for variometry, airspeed and altitude
measurements, the ADC has a three-axis
accelerometer, a two-axis (pitch and roll) rate
sensor and a three-axis magnetometer.
We plan to use the magnetometer data for
enhanced wind calculations and the rate and
accelerometer data for advanced variometry.
THE FUTURE
This is the second time around for both
owners of ClearNav Instruments and we now
work only because we choose to.
We have smart and committed people
working with us, and others interested in
joining us. We are in the process of building a
company which we look forward to
transferring them, thus ensuring that CNI will
continue to offer simple and innovative
products to this most demanding of markets.
These features will not however be available
with the first product release.
Included in the SFR option is a PC utility,
which allows tasks and waypoint files to be
shared with the ClearNav flight computer,
providing a completely independent back up.
Tasks entered directly into the ClearNav flight
computer are automatically transferred to the
vario. Navigation information may be
presented on the vario display.
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Gliding International (November-December 2011)