Cambridge Model 20 Issues

Greg Arnold wrote:

Brian Iten's file with the high noise reading in on the OLC site for
April 4, if anyone wants to look at it.

I think we need the original file (.cai format) from the logger. The
noise recordings look much too high for gear down noise. What program
was used to produce the IGC file from the CAI file? If it was the
cai2igc.exe, perhaps that program does not rescale the engine noise
level to the IGC values?
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Eric Greenwell
Washington State
USA

Eric,
I used the cai2igc program as I didn't know at the
time that I could do it in SeeYou. I will email you
the original CAI file tonight.
Brian


What program
was used to produce the IGC file from the CAI file?
If it was the
cai2igc.exe, perhaps that program does not rescale
the engine noise
level to the IGC values?
--
-----
change 'netto' to 'net' to email me directly

Eric Greenwell
Washington State
USA

X-no-archive: yes
In article , Eric Greenwell
writes
Greg Arnold wrote:

Brian Iten's file with the high noise reading in on the OLC site for
April 4, if anyone wants to look at it.

I think we need the original file (.cai format) from the logger. The
noise recordings look much too high for gear down noise. What program
was used to produce the IGC file from the CAI file? If it was the
cai2igc.exe, perhaps that program does not rescale the engine noise
level to the IGC values?

I have has a look at Brian's .IGC file and it show maximum values of
195, which suggests that any rescaling is being done by the viewing
program and not on conversion to .IGC format. The download was done
using SeeYou.

What I do see is that the maximum value of 195 (equivalent to 999 on any
other recorder, and top-of-scale for Cambridge 10/20/25) is reached and
sustained (flat tops to ENL graph) during both Take-off/Tow and final
stage of flight to landing (presumably when the wheel was down), as well
as occasionally during what I take to be urination.

The ENL on this recorder is abnormally high. A new design of recorder
showing these characteristics would not get IGC approval.

I would guess that the ENL system on this recorder is in need of
adjustment/repair.

Best regards,

Tim Newport-Peace.
Technical Advisor to
Global Navigation Satellite System
Flight Recorder Approval Committee (GFAC)
of the International Gliding Commission
of the Federation Aeronautique Internationale

I have emailed Cambridge about this and they informed
me that it was normal for engine noise detection when
the gear is down. I would love to see a trace with
a model 20 inside of a 1-26,2-33 or Blanik..... The
logger would probably self destruct from the noise......LOL
Brian
17

I would guess that the ENL system on this recorder
is in need of
adjustment/repair.

Best regards,

Tim Newport-Peace.
Technical Advisor to
Global Navigation Satellite System
Flight Recorder Approval Committee (GFAC)
of the International Gliding Commission
of the Federation Aeronautique Internationale

I have emailed Cambridge about this and they informed
me that it was normal for engine noise detection when
the gear is down. I would love to see a trace with
a model 20 inside of a 1-26,2-33 or Blanik..... The
logger would probably self destruct from the noise......LOL
Brian
17

I would guess that the ENL system on this recorder
is in need of
adjustment/repair.

Best regards,

Tim Newport-Peace.
Technical Advisor to
Global Navigation Satellite System
Flight Recorder Approval Committee (GFAC)
of the International Gliding Commission
of the Federation Aeronautique Internationale

I have emailed Cambridge about this and they informed
me that it was normal for engine noise detection when
the gear is down. I would love to see a trace with
a model 20 inside of a 1-26,2-33 or Blanik..... The
logger would probably self destruct from the noise......LOL
Brian
17

I would guess that the ENL system on this recorder
is in need of
adjustment/repair.

Best regards,

Tim Newport-Peace.
Technical Advisor to
Global Navigation Satellite System
Flight Recorder Approval Committee (GFAC)
of the International Gliding Commission
of the Federation Aeronautique Internationale

I have emailed Cambridge about this and they informed
me that it was normal for engine noise detection when
the gear is down. I would love to see a trace with
a model 20 inside of a 1-26,2-33 or Blanik..... The
logger would probably self destruct from the noise......LOL
Brian
17

I would guess that the ENL system on this recorder
is in need of
adjustment/repair.

Best regards,

Tim Newport-Peace.
Technical Advisor to
Global Navigation Satellite System
Flight Recorder Approval Committee (GFAC)
of the International Gliding Commission
of the Federation Aeronautique Internationale

I have emailed Cambridge about this and they informed
me that it was normal for engine noise detection when
the gear is down. I would love to see a trace with
a model 20 inside of a 1-26,2-33 or Blanik..... The
logger would probably self destruct from the noise......LOL
Brian
17

I would guess that the ENL system on this recorder
is in need of
adjustment/repair.

Best regards,

Tim Newport-Peace.
Technical Advisor to
Global Navigation Satellite System
Flight Recorder Approval Committee (GFAC)
of the International Gliding Commission
of the Federation Aeronautique Internationale

X-no-archive: yes
In article , Brian Iten
writes
I have emailed Cambridge about this and they informed
me that it was normal for engine noise detection when
the gear is down. I would love to see a trace with
a model 20 inside of a 1-26,2-33 or Blanik..... The
logger would probably self destruct from the noise......LOL
Brian
17

Some noise yes, but I would not expect it to be a maximum value.

I have a trace from a Ventus using a legacy Cambridge which gives much
more reasonable values.

Best regards,

Tim.
--


I would guess that the ENL system on this recorder
is in need of
adjustment/repair.

Best regards,

Tim Newport-Peace.
Technical Advisor to
Global Navigation Satellite System
Flight Recorder Approval Committee (GFAC)
of the International Gliding Commission
of the Federation Aeronautique Internationale

Brian


I have looked at your IGC file.
The issue for me is: what is the fully scale ENL level?

If it is 195, then you have a problem with the logger.
If it is 400 or 1000, then the logger may be recording entirely normally.
The higher ENL values also occur in both the circuits, suggesting that they
represent "wheel-down".
The highest glide of 100 knots only gives a reading of 40.

I would have expected to see a higher value at touchdown. I see no evidence
of a touchdown spike. Maybe you grease the glider onto a smooth runway! I
would also have expected a higher value at 100 knots.

I would recommend the following tests:
Put the logger into the tug plane and seem what ENL level is recorded -
expect over 800, if 195 then problems.
Try putting the logger somewhere else in the glider, such as the luggage
shelf, which should be more noise-sensitive than the top of the instrument
panel.

If you have neither Turbo nor SLMG then the ENL is not vital.

------------------------------------------------

I fly a DG800 SLMG with LX20 logger.
The ENL recording is between 0-1000.
I tend to review my flights using SeeYou with Map, Altitude and ENL windows.
This allows ENL noise to be reviewed and interpreted.

My values a
Engine running - never less than 800, normally about 900.
There is sometimes an after effect following the engine run and this seems
to take some minutes to return to normal levels, but not of the same order
as your noise levels. The engine noise also dips to 800 at the start of the
takeoff roll! I have not studied the post-engine run noise because it is
normally not very noticeable.

Touchdown spike 800
Winch launches 500-600.
Spins 600-800.
Engine up 500-700.
Normal flying 0-400.
High speed glides - 80kts 400, 90kts 550, 100kts 600, 120kts 800.
I can find a record of 600 at only 80kts.
I cannot tell from the ENL if the wheel is down, but it is colder and sounds
noisier in the cockpit. I have checked at least one "wheel down" flight.



Rory