GPS glide ratio calculations

Hi the

I think the Vista and will log altitude, but you have no control over
the timing of the recording unless it is a higher end version - it is
always automatic. The Garmin76 has long tracks and has better timing
control (more expensive though) - The GPS12X does not record altitudes.
Magellans have much worse support for logging tracks. They are always on
and you have almost no control over the track. I don't know about the
Flyer - it may be better. Occasionally the altitudes on GPS can be be
off and sometimes will jump around or plummet to the ground (goes to
zero suddenly because of loss of signal). I think you must keep the
antenna on the GPS clear of obstructions and then everything is fine. I
would say that the Garmin76 would be the best for your purposes.

On software - I have 3DTracer myself. It will calculate glide ratios as
you can select any section of the flight track and then perform
calculations on it. You can also load 3d maps from terrain DEM files.
(The animations are just amazing - but off topic I suppose). It is
cheaper than SeeYou and the animations are better - but less support for
OLC. I also looked at CompeGPS, too - it is geared to hanggliders - But
it had a few crashes on my machine and the 3D part was difficult to move
around in. The hard part in 3DTrace is getting the files properly set up
- the data is on the web you just must find it and calibrate the map
properly. Oh yes it also has a cool flight deck that shows you
everything thats occurring.

The other option is to hook up a PDA to the GPS and this can be your
logger - this has the difficulty that it is and extra cable, an extra
set of batteries and getting the software on the PDA. But it works - I
have the GPS12 with PDA software on an old Palm, with spliced together
cabling. It was around $500 altogether - $200 for GPS, $200 for the PDA,
$100 for the software - and you can use the PDA for its originally
intended use.

Any how my 2 cents


Kirk Stant wrote:
James,

Interesting hobby!

You could use a GPS logger (like a Volkslogger or Colibri), set to
minimum logging interval (1 or 2 seconds). You would have to download
the trace afterwards and use a program to view it. I would recommend
SeeYou, but some other more terrain-oriented programs might have
better terrain resolution (which would be important for you, I
assume).

This setup would require a small battery hooked up to the logger, but
with the short flight duration it shouldn't be too big.

Some of the newer Garmin handhelds also log altitude, they may be a
lot cheaper and just as useful. The key is probably going to be the
software you use to look at the trace.

Let us know how it works out.

Kirk
LS6-b "66"

Jack wrote in message ...
in article , Tom Seim at
wrote on 2003/09/08 23:52:

Character assignation is a definte debate loser.

Perhaps you meant "...assassination", rather than "...assignation"?

Yes, my fingers were a couple words behind my brain. Shows the problem
with spell check.



...pull up stall-spins following the low pass [are] an
essential part of the maneuver which would not have been
attempted had it not been for the low pass. Thus the low
pass was directly contributory to the accident.

I think you may have to go further and tell us how you define
"low pass". Are pull ups from three feet more dangerous than pullups from
ten feet, or one hundred feet, or three hundred? And by how much,
statistically speaking?

Now you are in the 'bring me a rock' mode. You are no more interested
in additional stats than you are in changing your mind on the matter.
The maneuver is an inherently high-risk one with little margin for
error. Blasting thru a busy GA airport such as the one where I fly out
of with piston A/C, turbine A/C, ultra-lights and helicopters is using
questionable judgment. Not all pilots are on the correct frequency or
have their squelch set properly. Some don't have radios at all. None
will be expecting this maneuver.

Some maneuvers are inherently more dangerous than others (i.e. ridge
soaring and landings). Their accident rate per flight hour WILL be
higher, but you don't see it referenced. It gets lumped into the
overall rate. All of us will be doing one landing for each flight; few
will be doing a low pass.



...training...for high speed low passes...isn't part of
the practical test standards and it certainly wasn't a
part of my training.

Then please don't do them. Nor should you presume to decide who is qualified
to do them and who is not, nor how much risk exposure is involved.


Judgment is the integration of training and experience.
Let the record speak for itself; this maneuver is,
deservedly, a high risk one.

The record merely tells us that some glider pilots have performed the low
pass maneuver poorly. You have no idea how many do it every day with success
and even aplomb.

Not many. I seldom see it performed. Most of them were done at
contests until the rules were changed over concern about safety. I
personally have done them at contests. And I admit it; they were fun!
With the new tasks which had gliders coming in to the finish line from
any direction, even though we all crossed the finish line in the same
direction, heightened the risk substantially.


It is a failing of our government-approved so-called system of training
which refuses to even acknowledge, let alone prepare pilots for, any number
of maneuvers which a competent pilot should have in his repertoire. No
wonder they occasionally do them poorly.


The current program doesn't even address cross country soaring. It
basically teaches gliding, not soaring. Yet much of the glider hours
flown are cross country. The Feds will change training requirements
when they see unusually high accident rates, which is probably just as
well because we would have a real problem getting instructors.

Let me be clear about one thing: the low pass maneuver is legal except
where prohibited by local A/P rules (assuming you don't violate some
other rule in the process). I have no intention of petitioning the FAA
otherwise (have you read the posts by the club that is having major
difficulties with the A/P management?). I was expressing my opinion to
which I am entitled, and just think that low time pilots should not be
attempting it. Now, the bird man thing is another story.

Sorry, but I still don't see it. Two accidents in 20
years doesn't strike me as a top ten safety issue.
Certainly finding better ways to train for more advanced
forms of soaring (cross country, racing, acro, etc.)
and exercising good judgement generally are motherhood
issues for the sport.

I think it is possible to construct worst case scenarios
for any phase of flight and thinking about these scenarios
may prove instructive for the development of flying
judgement -- after all judgement is generally born
out of learning from experience. If you construct a
low pass scenario of gliders converging from different
directions on a busy, mixed-use airport without proper
radio procedures or situational awareness, crossing
active runways without looking, squeezing between buildings
and frightening the children it starts to sound reckless.
But in my view that is a debating canard. I can make
a simple pattern tow sound dangerous with similar 'scenario-buildi
ng' just by adding in high crosswinds, local thunderstorms,
poor preflight procedures... you get the picture.

If there are facts about actual accidents (Tom's search
turned up two that were of questionable applicability
since I don't think we're talking about attempting
loops at low altitude as a standard procedure), or
facts about near misses where another aircraft was
forced to take emergency evasive action, then maybe
there can be a productive discussion about what to
do to improve safety. But the facts don't seem to bear
this out.

Tom, I don't dispute your general points about judgement
and training, I just think we need to be careful about
characterizing certain types of flying as inherently
risky if the real point is reckless or thoughtless
flying in any phase of flight is potentially dangerous.
The first thought tends to lead to rules and regulations
about specific flight procedures (e.g. no low-passes,
no more than one glider in a thermal, no ridge soaring,
no landings [okay that might be a tough one to implement]),
but if the real issue is poor judgement generally,
than all the rules do is take the fun out of flying
and give some people a false sense of security. Some
of the clubs I've belonged to that have been the most
'rule happy' actually have poorer safety records (no
I don't have statistics). I'd hate to distract people
away from the real safety issues, which (according
to the statistics) have to do with maintaining proper
control of the aircraft and adequate flying speed/coordination.

Hope these thoughts are viewed as constructive - it's
how they are intended.

9B

At 01:54 10 September 2003, Tom Seim wrote:
Jack wrote in message news:...
in article ,
Tom Seim at
wrote on 2003/09/08 23:52:

Character assignation is a definte debate loser.

Perhaps you meant '...assassination', rather than
'...assignation'?

Yes, my fingers were a couple words behind my brain.
Shows the problem
with spell check.



...pull up stall-spins following the low pass [are]
an
essential part of the maneuver which would not have
been
attempted had it not been for the low pass. Thus
the low
pass was directly contributory to the accident.

I think you may have to go further and tell us how
you define
'low pass'. Are pull ups from three feet more dangerous
than pullups from
ten feet, or one hundred feet, or three hundred? And
by how much,
statistically speaking?

Now you are in the 'bring me a rock' mode. You are
no more interested
in additional stats than you are in changing your mind
on the matter.
The maneuver is an inherently high-risk one with little
margin for
error. Blasting thru a busy GA airport such as the
one where I fly out
of with piston A/C, turbine A/C, ultra-lights and helicopters
is using
questionable judgment. Not all pilots are on the correct
frequency or
have their squelch set properly. Some don't have radios
at all. None
will be expecting this maneuver.

Some maneuvers are inherently more dangerous than others
(i.e. ridge
soaring and landings). Their accident rate per flight
hour WILL be
higher, but you don't see it referenced. It gets lumped
into the
overall rate. All of us will be doing one landing for
each flight; few
will be doing a low pass.



...training...for high speed low passes...isn't part
of
the practical test standards and it certainly wasn't
a
part of my training.

Then please don't do them. Nor should you presume
to decide who is qualified
to do them and who is not, nor how much risk exposure
is involved.


Judgment is the integration of training and experience.
Let the record speak for itself; this maneuver is,
deservedly, a high risk one.

The record merely tells us that some glider pilots
have performed the low
pass maneuver poorly. You have no idea how many do
it every day with success
and even aplomb.

Not many. I seldom see it performed. Most of them were
done at
contests until the rules were changed over concern
about safety. I
personally have done them at contests. And I admit
it; they were fun!
With the new tasks which had gliders coming in to the
finish line from
any direction, even though we all crossed the finish
line in the same
direction, heightened the risk substantially.


It is a failing of our government-approved so-called
system of training
which refuses to even acknowledge, let alone prepare
pilots for, any number
of maneuvers which a competent pilot should have in
his repertoire. No
wonder they occasionally do them poorly.


The current program doesn't even address cross country
soaring. It
basically teaches gliding, not soaring. Yet much of
the glider hours
flown are cross country. The Feds will change training
requirements
when they see unusually high accident rates, which
is probably just as
well because we would have a real problem getting instructors.

Let me be clear about one thing: the low pass maneuver
is legal except
where prohibited by local A/P rules (assuming you don't
violate some
other rule in the process). I have no intention of
petitioning the FAA
otherwise (have you read the posts by the club that
is having major
difficulties with the A/P management?). I was expressing
my opinion to
which I am entitled, and just think that low time pilots
should not be
attempting it. Now, the bird man thing is another story.

In article ,
says...
I've never heard of a fatality, or even
an accident during a 'contest finish' - either during
a contest or at any other time, though I cannot say
definitively that it's never happend.

Here are two I can definitively remember:

A fatality occurred after a low pass at California City contest a few
years ago.

There was a famous accident at our local regional many years ago,
where a pilot finished too slowly, pulled up, and flew through the
aerials on the Flight Service Station. No injury, limited damage, very
lucky.

My personal experience
(and statistics on the subject) suggests that we should
be more concerned with too little speed (stall/spin)
than too much speed.

The scary low passes I've seen were almost all done with too little
speed, which means when the pilot pulls up, he is still low, making a
pattern (any kind of pattern) to the landing more difficult.

--
!Replace DECIMAL.POINT in my e-mail address with just a . to reply
directly

Eric Greenwell
Richland, WA (USA)

"Eric Greenwell" wrote in message
.. .
In article ,
says...
The scary low passes I've seen were almost all done with too little
speed, which means when the pilot pulls up, he is still low, making a
pattern (any kind of pattern) to the landing more difficult.

--
!Replace DECIMAL.POINT in my e-mail address with just a . to reply
directly

Eric Greenwell
Richland, WA (USA)


A "rule of thumb" I've used is 1 knot = about 9 feet. So if I start the
pull-up at 110 knots and push over to level for the pattern at about 60
knots, I'll be around 450 feet plus whatever altitude the low pass was flown
at.

I've done a few low passes at Napa, CA, a towered airport. I never ask when
there's other pattern traffic and so far the tower has always cleared me for
the low pass.

Disclaimer: the "formula" above isn't mine, don't know where I read it, it's
probably inaccurate, and don't try it at home . . . or in a glider for that
matter and try it at altitude first.
--
bumper
"Dare to be different . . . circle in sink."
to reply, the last half is right to left




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The rule I use is simple
At ground level!
70knots to 90 knots I have enough energy for a 180degree turn
90 knots + I have energy for 360 degree turn.
THESE ARE ABSOLUTE MINIMUMS.
I add 10-20knots to avoid a case of "brown adrenalin"
These figures are calculated on Cirrus,Libelle,Asw19 type aircraft
so later generation gliders gain on on these figures
I REPEAT I ADD 10-20 KNOTS FOR SAFETY
These figures were calculated about by a well known pilot
15-20 years whose name I cannot recall.
gary
"John Morgan" wrote in message
...

"Eric Greenwell" wrote in message
.. .
In article ,
says...
The scary low passes I've seen were almost all done with too little
speed, which means when the pilot pulls up, he is still low, making a
pattern (any kind of pattern) to the landing more difficult.

--
!Replace DECIMAL.POINT in my e-mail address with just a . to reply
directly

Eric Greenwell
Richland, WA (USA)


A "rule of thumb" I've used is 1 knot = about 9 feet. So if I start the
pull-up at 110 knots and push over to level for the pattern at about 60
knots, I'll be around 450 feet plus whatever altitude the low pass was
flown
at.

I've done a few low passes at Napa, CA, a towered airport. I never ask
when
there's other pattern traffic and so far the tower has always cleared me
for
the low pass.

Disclaimer: the "formula" above isn't mine, don't know where I read it,
it's
probably inaccurate, and don't try it at home . . . or in a glider for
that
matter and try it at altitude first.
--
bumper
"Dare to be different . . . circle in sink."
to reply, the last half is right to left




---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.514 / Virus Database: 312 - Release Date: 9/1/2003

Andy Blackburn wrote in message ...
Tom,
I took a look at your references -- by N#. The first
and third appear to be low passes - though in both
cases they were in the context of doing low-altitude
aerobatics, rather than traditional 'contest finish'
maneuvers, but I'll let them pass. The reports on the
second and fourth had no references to low, fast passes.
The BG-12 lost a wing at 2000' and the Blanik was just
high on approach. (Excerpts from the accident reports
attached).

Your formula for estimating accident rate by phase
of flight seems ok, but you have to be careful about
making conclusions from VERY low rates of occurence
(i.e. one every ten years). Also, I would disagree
with your estimate of 1,000 operations for
high-speed passes in the US in a year. The Arizona
Soaring Association weekend contest series generates
over 200 contest finishes in a summer - and that's
just one soaring site. Add all the other sites in the
US, plus sanctioned contests and you get a much bigger
number. Finally, you used 9 years for the time period,
but your examples spanned 19 years (1984 to present).
Given the low rate of occurence, I emphasize that calculating
a rate is likely to be misleading. The rates associated
with landing phase would seem to be higher, since there
we have several per year.

In any event, I remain unconvinced that making contest
finishes is inherently dangerous, particularly now
that the evidence in favor of the argument has been
presented.


Those two accidents were mostly caused by a badly botched attempt at a
hihg-speed low pass. The pilot of the BG-12 exceeded Vne; why did he
do that entering the pattern? The only ligit explanation, in my mind,
is that he was starting a low pass and didn't pay attention to
airspeed. The other one was very curious. They described a high pass,
yet he hit A/C on the ground! These two statements are completely
inconsistent:

WITNESSES REPORTED THAT THE ACFT APPEARED TO BE TOO
HIGH, TOO FAST, AND IN A CRAB AS IT APPROACHED THE
RWY. OVER THE RWY THE GLIDER WAS OBSERVED TO ROLL INTO
A RIGHT TURN AS THE NOSE CAME UP. SHORTLY THEREAFTER
THE RIGHT WING STRUCK 3 PARKED ACFT AND COLLIDED WITH
THE TERRAIN.

I concluded that the glider wasn't as high as the witnesses thought
(surprise!) and that he was doing a show off low pass for his
passenger (surprise again).

The accident rate calculation is illustrative, giving an order of
magnitude to the situation. You can adjust the calculation by
assigning an educated probability to the accident falling in this
category; it doesn't change things materially. If you compare this,
small, category to all fatal accidents it is totally out of proportion
by any measure.

Your attitude from the outset has been "show me!". I've been in this
sport a long time (over 20 years), and that's a red flag attitude in
my book. I'm sure you've seen pilots who over estimate their
capabilities, given your resume. I've grown more conservative in my
old age (old pilots vs bold pilots). I say to you, show me how it is
safe, considering ALL conditions, such as pilot capabilities and
surroundings (i.e. glider only A/P vs GA A/P). The bottom line is: is
it worth it? Are you going to assume an avoidable risk vs a quick
thrill? My message isn't to you guys (you're already to emotionally
invested in proving me wrong), its to low time pilots who are
wondering what's this all about. Do I really have to explain what is
wrong with showing off? Are you guys so thick skulled as to not see a
problem with that kind of attitude? If so I hope I don't see your name
on an NTSB report. I have said it befo I would rather have someone
****ed off at me for voicing my oppinion than to stand silent and
watch them kill themselves. Personally, given your background I am
surprised at your attitude. I will consider my comments a complete
success if I have thrown a note of caution into just a single pilot,
or pilot to be, that has followed this exchange.

BTW: Go for the glass!