Three leg GS to TAS calculation

And it is the easiest of all to simply forget about time and distance
altogether and use the website.



Marc J. Zeitlin wrote:
john smith wrote:


If each leg is the same distance, use time not airspeed. Then convert
the average for one leg length. Headwinds, tailwinds, crosswinds

cancel.

OK, I'll agree with that, but it's a LOT easier to fly for a fixed TIME
than for a fixed distance, unless you fly at about 10' AGL......

"Mike Rapoport" wrote in message
link.net...
Does anybody know the calculation to get TAS from the GS of three legs 90
deg apart? Thanks.

Mike
MU-2



Not exactly, Mike, but Ed Willams has it for legs 120 deg apart.

http://williams.best.vwh.net/avform.htm#3gs

Stan

Mike Rapoport wrote:
: Does anybody know the calculation to get TAS from the GS of three legs 90
: deg apart? Thanks.

: Mike
: MU-2

So, how fast is the Helio? I would guess about 0.35 MU-2 units... of
course I've never seen an MU-2 with floats, either...
--
Aaron Coolidge

In article ,
Aaron Coolidge wrote:

So, how fast is the Helio? I would guess about 0.35 MU-2 units... of
course I've never seen an MU-2 with floats, either...

They made one but it was so loud during taxi that the water cracked
open and it sank.

--
Ben Jackson

http://www.ben.com/

A little better actually. On Saturday I measured 140kts at 5000' and 50F at
the recommended cruise setting.

The airspeed indicator seems to read correctly at cruise but it reads at
least 8kts high around 55kts.

Mike
MU-2

"Aaron Coolidge" wrote in message
...
Mike Rapoport wrote:
: Does anybody know the calculation to get TAS from the GS of three legs
90
: deg apart? Thanks.

: Mike
: MU-2

So, how fast is the Helio? I would guess about 0.35 MU-2 units... of
course I've never seen an MU-2 with floats, either...
--
Aaron Coolidge

Mike Rapoport wrote:
: A little better actually. On Saturday I measured 140kts at 5000' and 50F at
: the recommended cruise setting.

Excellent! I guess 0.35 MU-2 is around 110kts?

: The airspeed indicator seems to read correctly at cruise but it reads at
: least 8kts high around 55kts.

I can't speak for the Helio, but many Cessna airplanes have a conversion
table in the POH that describes the CAS - IAS differentials. It's quite
large at lower airspeeds, as I recall. I presume that its due to pitot/static
errors that are not cancelled out (as they could be with an air data
computer). Do you suppose this may be the reason for the discrepancy?
The Cessna tables also noted that despite the error between CAS and IAS,
the range markings on the airspeed indicator were accurate. In other words,
Vs0 was at, say, 44kts IAS and that was marked on the airspeed indicator,
while the calibrated Vs0 was a different number. I can't remember the exact
wording, and I gave away my Cessna stuff years ago.

Anyway, have fun with the new toy.
--
Aaron Coolidge

"Aaron Coolidge" wrote in message
...
Mike Rapoport wrote:

: The airspeed indicator seems to read correctly at cruise but it reads at
: least 8kts high around 55kts.

I can't speak for the Helio, but many Cessna airplanes have a conversion
table in the POH that describes the CAS - IAS differentials. It's quite
large at lower airspeeds, as I recall. I presume that its due to
pitot/static
errors that are not cancelled out (as they could be with an air data
computer). Do you suppose this may be the reason for the discrepancy?
The Cessna tables also noted that despite the error between CAS and IAS,
the range markings on the airspeed indicator were accurate. In other
words,
Vs0 was at, say, 44kts IAS and that was marked on the airspeed indicator,
while the calibrated Vs0 was a different number. I can't remember the
exact
wording, and I gave away my Cessna stuff years ago.

I'm not sure of the cause of the descrepancy. It could be water in the
pitot line or an error in the instrument. I am aware that most airplanes
have increasing IAS errors at lower speeds. My issue is that the IAS points
for my airplane seem to be quite a bit higher than in the skimpy flight
manual and higher than other people are getting. The Helio was certified in
the bronze age and only has minimal documentation. There are no detailed
charts for anything.

Anyway, have fun with the new toy.

I am!


Aaron Coolidge

Any leaks in the system?

Mike Rapoport wrote:
I'm not sure of the cause of the descrepancy. It could be water in the
pitot line or an error in the instrument. I am aware that most airplanes
have increasing IAS errors at lower speeds. My issue is that the IAS points
for my airplane seem to be quite a bit higher than in the skimpy flight
manual and higher than other people are getting. The Helio was certified in
the bronze age and only has minimal documentation. There are no detailed
charts for anything.