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ClearNav News



February 9, 2017 - ClearNav CNv NavDisplay XC Manual Updated

The new manual updates cover Release 3.5.4xx and forward. View CNv XC Manual Pages


February 1, 2017 - Clear Nav Instruments Under New Management

Effective Feb 1 2017.  Clear Nav Instruments Inc. has been sold to and is now under the management of Rex and Noelle Mayes of Williams Soaring Center (WSC) located in Williams Ca.  The  development, manufacture, assembly, distribution, support and repair operations will be headquartered at WSC.

Gary Kammerer  remains available for support and repair services in his new location in Vermont.  Chip Garner, David Masson and Angus Raby will remain on the development team.   Richard Kellerman and Tim Welles remain committed to serve in consulting roles for the purpose of  mechanical engineering and testing.

There are no immediate plans to change the dealer net work.

Watch this website for updates.

Rex and Noelle are excited about the future of the ClearNav line of soaring instruments and are committed to the continued research and development to produce this state of the art equipment.

Please visit to learn more about Rex and Noelle and the WSC family of soaring services.

January 7, 2017 - New Variometer Release 3.5.4171

This release (3.5.4171) fixes a rarely occurring bug that can impact serial communications with a ClearNav or third party device. We strongly recommend all users move to this version of the CNvario software.

A profile generated with the CNvUtility  v3.5.2 is required to be able to use the new features in CNv v3.5.4089 and higher releases.  CNvUtility v3.5.2 is available in the ClearNav Downloads page.

See the CNv and CNv Utility Release Notes and Instructions on the download page for details.

November 8, 2016 - New Variometer Release 3.5.4155

The vario release provides some minor functional and display enhancements ... and includes some minor bug fixes.

The CNv Utility now identifies features that are not available in the CLUB version, and also provides additional function to specify and graphically view aircraft polars.

A profile generated with the CNvUtility  v3.5.2 is required to be able to use the new features in CNv v3.5.4089 and higher releases.  CNvUtility v3.5.2 is available in the ClearNav Downloads page.

See the CNv and CNv Utility Release Notes and Instructions on the download page for details.

September 1, 2016 (Updated October 1, 2016)


Gary's new address in Vermont follows:

Gary Kammerer
ClearNav/Cambridge Service/Support
144 Daltons Rd
Waterbury, VT 05676


We will be making some changes to the way we handle support for CAI products and request that anyone needing CAI service contact Gary prior to shipping.

Richard, Tim, and Gary

August 5, 2016 - New ClearNav II Release

The newest ClearNav II Release (V3.0.2.17) contains features for FLARM configuration and display, FAI Task configuration, and log file management.

See the CN II Flight Computer Software and Factory Memory Stick Release Notes and Instructions on the download page for details.

July 9, 2016 - New Variometer Release 3.5

This release includes a number of new and upgraded vario features for your XC version that will enable you to climb bettter and optimize cruise performance.

The 3.5 Beta release incorporates all changes made since the last public release, 3.3.3899.

To use the new features in this release, you MUST use a profile which has been produced from the CNvUtility3.5 which is included with this beta release.

See the CNv and CNv Utility Release Notes and Instructions on the download page for details.

February 25, 2016 - New Variometer Release 3.3.3899

The 3.3 release incorporates all changes made since the last 3.1 release (3.1.3533).  This includes all the enhancements and fixes previewed in the 3.2 beta releases.

This version includes updates for: 1/ Therrmal Assist Tool 2/ CAI dataport enhancements for Oudie, SeeYouMobile & other 3rd party devices 3/ Various Bug Fixes.

See the Release 3.3. Download Release Notes for details.

September 23, 2015 - ClearNav I to ClearNav II Upgrade - $1000

How to Upgrade (11/21/2016)

Call Richard Kellerman, schedule a date and send him your ClearNav.  Only the ClearNav needs to be returned – the Nexus box and controller can stay.  Richard will upgrade your ClearNav and you can reinstall it in your glider.

ClearNav Instruments
256 Old Kennett Road
Kennett Square, PA 19348


  • Even brighter screen and higher contrast
  • Lower power consumption
  • Much faster processor which gives instant response to keypad inputs
  • New processor will also allow us to add new features
  • Faster screen refresh rate for easy roll out of thermals onto course
  • Full mechanical compatibility with ClearNav I

The original ClearNav (“ClearNav I”) was built on the best hardware available at the time.  As we continued to add features the instrument started to show the strain and quite a few things took longer to happen than our pilots would have liked.

We picked a new much more capable processor and mated it to a redesigned motherboard.  We also took the opportunity to switch to LED backlighting which is much more efficient than the original CCFL backlights. 

A complete re-write of the software was also done to make the system more stable and to make it easier for us to add new features.  The next release will use color coding of course lines and task areas to clarify navigation and we are currently working on new FLARM features.

CNI CNII Compatibility
The CNI and CNII enclosures are identical so upgrading is simple.
With the release of CNII we will no longer be able to add new features to the CNI (although we will of course release bug fixes as needed).  The $1,000 upgrade cost is a very fair route to extend the life and value of your original ClearNav purchase, and we hope you will agree.

August 21, 2015 - ClearNav Vario Software Release 3.1

Version 3.1 is a major upgrade from the 2.7 release. It contains many enhancements that have already been released in beta form (versions 3.0.xxxx beta) and contains a few more improvements and bugfixes over the last beta release as well. See the release notes in the download section for more details.

April 3, 2015 - ClearNav Vario Software Release 3.0.3332 - Beta

We have made major changes and improvements  in the CNv vario software for both the Club model and the XC license models.  

Both varios now have dramatically improved digital filtering, allowing us to provide a variometer  with a response which is both fast and smooth.  The response is fast enough to allow centering without reference to anything but the audio feedback.

When the lift changes so does the audio, with almost no lag.  The fast smooth response, coupled with a very effective auto cruise/climb algorithm, gives the pilot the information needed to make the correct turn/don’t turn decision.

The audio tones have been modified to a more pleasing sound, and more importantly we have changed the repetition rate and tone frequencies to provide greatly improved feedback on lift strength.

Major improvements and changes in the wind calculations, presentations, and options have also been made.  It is now possible to set and activate a manual wind for final glides if wind speed and direction are known or expected to be significantly different from the winds aloft.

Significant improvements have been made in the automatic wind calculations, with particular emphasis on techniques to assess the raw data quality and reject samples which are “noisy”.  A new “Quick Wind” tool makes possible a fast (5 – 10 seconds) wind update by simply making a small heading change. 

Either automatic or manual winds are presented on the flying screen.  Quick winds uses a separate screen.

Navigation tools have been expanded in the XC vario.  In addition to “Recent” waypoints it is now possible to select waypoints on an alphabetically sorted list, a distance sorted list, or a numerically sorted list. 

A redesigned user-configurable screen (available only on the NAV display) now includes the option of either a vario (or Netto or Relative Netto) tape display or a push/pull commander, wind- in-use (either automatic or manual), active waypoint with distance and height required, and a steering bug.  Both MC and volume can be set from this screen.

The result is that pretty much everything the pilot needs to know and do is available and can be done without leaving this screen.

Tasks created in “SeeYou” can now be loaded into the XC vario using a USB drive and the Task /edit tools have been .

In addition to the above we have made numerous small but important improvements which can be checked out in the Release Notes.

December 23 2014 - ClearNav II Product Announcement

We have been working since early 2014 on the development of new ClearNav hardware and software which will significantly improve the functionality of the ClearNav Flight Computer.  The new product will be known as “ClearNav II". Details here:

September 27, 2014 - CAI 302 Repair Policy

CAI 302 Repair Policy

Effective immediately we are moving to a fixed price service policy.  For $350* we will

  • Repair almost any 302**
  • Clean and test and inspect as appropriate, connectors, boards and components
  • Calibrate the altitude pressure transducer and provide a new calibration certificate
  • Issue a full one-year warranty to cover the entire instrument, not merely the repaired items

*There will be a minimum charge of $125.00 if no defects are found and the unit is determined to be functioning perfectly.

**Almost any – we reserve the right to return at no cost any instrument which we judge not repairable – for example if you drove the trailer over it or filled it with water in a water landing.

August 15, 2014 - Updated Audio Files Available for ClearNav Flight Computer

The 'airspace' and 'airspace above' warning audio levels were increased to match the flarm warnings i.e. the prior airspace warnings were not audible with volume set for flarm warnings.

July 8, 2014 - ClearNav Instruments “CNv” Vario now Certified for OLC

The new “XC” license pack for the CNv vario - and flight recorder certified for World records - are now accepted by the OLC.

June 12, 2014 - New CNv Nav Display

ClearNav Shipping New Nav Display for Vario

A  new  option for the CNv vario – can be used either as a supplement to the standard display or as a replacement.  With an XC software license you can have a completely independent task management screen while keeping vario info on the standard display.  For the many fans of the CAI303, the CNv Nav display will be immediately welcome and familiar in your panel  and it has the added advantage that you can use the new Flight Screen with its integrated vario, navigation and wind information as your primary screen. 
  • Easy to see and read, easy to use, easy to install
    • Super high contrast reflective LCD,  low power consumption and wide temperature range
    • Can  be mounted over an existing 57MM hole or on a stalk (available separately)
    • Simple user interface controlled by five buttons
  • New Flight Screen for cruise and climb to give the pilot more information for optimizing performance in both flight regimes:
Moving Map Display*

  • Available for both Club and  XC licenses but navigation functionality is limited to Get Home with Club license


    • 5/8” (16 mm) thick and 2.6“ x 2.6” (66 mm x 66 mm)
    • Weight 2.3 Oz (65 g)
    • Screen  diagonal  2.7” (68 mm)
    • Resolution 400 x 240
    • Operating temperature range -20C to +70C
    • 70 mA typical current 

*Additional  features are planned for the moving map display.  Currently TP geometry is  limited to FAI sectors and 0.5 km circles.  No cylinders (Start, Finish, Area).  Manual advance to next task point.  No terrain, culture, or airspace.


  • For customers owning a CNv vario (XC or Club) on or before July 01 2014: $425
  • After July 01 customers may specify either the original mechanical  pointer display, or the new Nav display at the same system price of $2,300.
  • After July 01 customers may choose to purchase a system with both display options for $2,900 and any existing customer can add a Nav display for $550.


May 2, 2014 - New CNv Software Release

ClearNav Instruments released a new version of CNvario software (v2.2.2362) on 5/2/2014.

This release adds the capability of loading SeeYou waypoint files (.CUP) into the CNVario.

Files in the .STX format will continue to work and lat/lon coordinates in decimal minutes are now accepted.

Other minor improvements and bug fixes are included.

The new version is available in the download section.

April 17, 2014 - IGC Secure Flight Recorder Approval

We are pleased to announce approval from the IGC for our ClearNav Vario Secure Flight Recorder (CNv-IGC).

Additional details here.

February 23, 2014 - New CNv Software Release

ClearNav Instruments released a new version of CNvario software (v2.5.2181) on 2/23/2014.

This version will provide CNv CLUB features, and with the purchase of a license, CNv XC features. 

CNv XC Preview software versions prior to 2.5.2181 will no longer provide access to the XC features after 2/28/2014. 

Pilots who desire CNv XC features can purchase a license code from their ClearNav dealer.

Refer to the DOWNLOADS page for download and license activation instructions.

January 27, 2014 - CNi expands CAI support capability

ClearNav Instruments and Roy A. Ridgeway are pleased to announce that they have reached an agreement under which will allow CNi to acquire a large inventory of CAI 300 Series parts and assemblies. This will enable CNi to provide service world-wide for years to come for the many CAI customers still flying with the CAI 300 Series instruments.

With the implementation of this agreement CNi is now able to service any of the following CAI products:

  • GPS-NAV™ Datalogger
  • GPS-NAV™ Display
  • L-NAV™ Glide Computer
  • S-NAV™ Glide Computer
  • CAVII™ Variometer
  • 302/303/306

All inquiries should be to Gary Kammerer, either by phone (610-388-0456) or email (

January 8, 2014 - ADC Issues Resolved

XC Preview v 2.4.1946

This version fixes some infrequent, but pesky bugs that have bothered us for quite a while.  They were mostly evidenced by the ADC crashing and displaying the message “WARNING: No ADC”.

David Masson, our software programmer is quite confident that this fix eliminates a number of small problems.

It is strongly recommended that if you have installed v. 2.4.1934 (beta release 12-30 2013), that you replace it as soon as possible with this version.

This is still a beta release, so any observed problems should be reported to Gary Kammerer or Tim Welles.

December 31, 2013 - CNv XC Preview Period Extended

XC Preview v 2.4.1934 

This release extends the free XC Preview until the end of February, 2014.  Following that date, a license available to be purchased from ClearNav Instruments will be required to us the CNvario XC software.

New Features:

  • A Task Editor screen and an Active Task screen has been added to the Navigation Ribbon
  • A Flight Recorder function is now included.  It is not yet secure, or igc approved, but that is coming soon
  • During the startup sequence, an altitude screen is shown after gps reception is established.  One screen to the right will be an OAT screen (if no OAT probe installed) where the current OAT can be entered if desired
  • A Review Settings screen has been added to the Info Ribbon
  • There is a new Tools Ribbon, which includes:
    • Download Flights screen
    • Log Interval screen
    • Waypoint Data Management screen
    • Profile Management screen
    • License Management screen (future)
    • Pilot Event (PEV) screen
    • OAT screen
  • An XC Addendum to the Users Manual is available on our website

As v 2.4.1934 is a beta, we are quite interested in feedback as to how it works.  Please email feedback (good or bad!) to or

Software and release notes in the download section.

September 10, 2013 - Navigation added to CNv XC Preview

The latest Beta release of the XC software is now available for free download.  There are some minor improvements, including a clean-up of the all important Cruise and Climb screens, but the big news is that it's now possible to use your CNv for GPS navigation.

The ribbon menu now contains a Navigation entry:

From this you can access waypoint lists ranked by recent, WP number, or landpoint distance.  There is also a sorted list of all waypoints ranked alphabetically and numerically within type which allows selection from an alphabetically sorted list of control points, followed by an alphabetically sorted list of all points in the database.

When any waypoint is selected the navigation screen appears:

and can be accessed at any time using the top left knob – the navigation screen is positioned to the right of the MC and Wind screens.

Although the navigation functionality has been fully implemented in the vario display we are also going to be offering a second display dedicated to navigation functions.  Next up the Flight recorder – standby for further news.

Note that if you are using a prior version of XC Preview, the XC features stopped working as of 8/8/2013.

CNv XC Preview Software is available in the download section. This free version expires as of 12/31/2013.

The CNv XC user manual is available here.

August 9, 2013 - New ClearNav Beta Released -

This latest version adds a significant number of exciting new features to the ClearNav Flight Computer.
The software has had a reasonable amount of flight testing, However we cannot be sure there are no lurking bugs, so we ask your cooperation in reporting if any are experienced.

- Enhancements for TAT and MAT tasking

- FLARM Voice Alerts

- Various Bug fixes

Software and release notes available (here).

ClearNav Beta Software version is available in the download section.

August 7, 2013 - CNv XC Preview Period Extended

CNv XC Preview Update  (7 August, 2013)

This latest version of CN vario software extends the preview period.

Note that if you are using a prior version of XC Preview, the XC features will stop working as of 8/8/2013.

Software and release notes (here).


July 13, 2013 - CNv XC software available

CNv XC Preview Update  (13 July, 2013)

This latest version of CN vario software extends the preview period so users can continue to use the CNv-ClearNav serial communication while we work on exciting new XC features.

Serial communications from the CNv have been shown to work with a number of third party devices.  You are welcome to try this, but CNi is unfortunately unable to help troubleshoot any issues that arise.

Also, the cruise averager (Netto/Relative Netto) has been improved and is much more stable and useable.

Note that if you are using the 2.2.1314 version of XC Preview, the XC features will stop working in a few days.

See release notes (here) for details.

June 17, 2013 - CNv XC software available

Preview versions of the CNv XC software are now being made available.  The first release (available 2013-06-17) supports serial communication between the CNv and the ClearNav.  See release notes (here) for details.

May 31, 2013 - CNv Software Released

A major upgrade to CNv and Utility Program software is available in the download section. Please read the special notes for details.

New or Changed Utility Program Features

  • Cruise-Climb Switching
  • Connections to the Ten-Position Connecter on the Air Data Computer
  • Entering Polar Data

New or Changed CNv Features

  • Screen Access
  • Gear and Spoiler Warnings
  • Revised Cruise Screen
  • Multi-Profile Support
  • Automatic Cruise/Climb switching
  • Winds
  • Get-Home navigation
  • Electronic TE compensation


April 12, 2013 - Vario Feedback

Some feedback from pilots currently evaluating the new and enhanced software

“With the new software, the CN Vario is better than my Schuemann which has been installed in my ships for the past 20 years....The Netto and  TE compensation are the best ever”

John Seymour (SM)

"Overall, you have an excellent instrument here! It’s the best vario I’ve ever used. It has instantly improved my flying. The CNv will be my primary Vario for the upcoming racing season. Once you get the USB problems fixed you’ll have a great product. I’m looking forward to the XC version!”

Bif Huss (H7)

“Bloody good vario”

G Dale

Not all testers had such glowing praise but we are making rapid progress in fixing any and all issues which have arisen and we are very confident that all our customers will be this happy within a few weeks.

More Beta Testers Needed for v2.0.1194

Our first round of beta testing has gone well and we are now ready to get more customer  input.  We are looking for about twenty pilots able to fly this coming weekend, willing to provide feedback, and willing to accept the risks that always accompany beta releases.  

Anyone interested in helping us should email Gary Kammerer (  and he will send you the latest beta, plus installation instructions and the new PC utility app.

New features and improvements include:

  • A highly effective automatic cruise/climb algorithm with the option for a manual override
  • Faster TE response with even better gust rejection
  • Wind speed and direction screen
  • Basic get home GPS navigation
  • Electronic (no TE probe) TE option
  • In-flight adjustment to TE probe response
  • Unrestricted units choices
  • An improved PC utility app
  • Better and simpler update process

March 13, 2013 - Vario News From Seniors

Cold, windy and blue here but I have flown four days for about 11 hours.

Several pilots are currently flight testing the latest code for the ClearNav Vario "Club" model.  In addition to numerous improvements in basic variometry functions, we have added wind calculations and basic navigation.

So far the vario is meeting all our expectations and we are still aiming at a March 31 release.

We are also progressing with the additional features required for the XC model and will announce a target release date soon.

Richard Kellerman & Tim Welles, Lake Seminole Gliderport, FL

March 5, 2013 - "ClearNav" Software

ClearNav Alpha Software version is available in the download section.

Changes in since Version

- Fixed 302 communications bugs
   ……waypoint upload
   ……MC, bugs and ballast synchronization
   ……log file download

- SUA voice alarms

- Flarm alarm displays for at least 16 seconds

- Fixed below sea level filling with ocean color


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