Author: "gingy1raylynn" <gingy1@...> Time: Thu May 30, 2002 1:20 pm PDT Link
To all,
Hypothetically, let's say I'm going to have two types of airspeed
indicators in my aircraft, for redundancy of course. I am
considering the Blue Mountain EFIS, but also want a mechanical backup
in case Murphy stows away. The first question is "Does Blue Mountain
require a specific pitot tube, their own, probably?". But this is
not why I'm writing. For arguments sake, let's assume that it can
utilize a normal pitot tube, would it be possible to split the pitot
feed to go to two different ports (two different instruments, i.e. BM
EFIS, and a normal mechanical airspeed indicator)? I understand
static air is static air....But, wouldn't a split in a ram-air-
pressure source effectively halve the pressure in the system to the
different guages? Would two pitot tubes be required?
Thanks,
Eric
Author: "Greg Young" <gyoung@...> Time: Thu May 30, 2002 4:23 pm PDT Link
No, one pitot tube will work. Since there is no exhaust (nor leaks) from the
instruments, there is no flow so you can have as many pressure sensors as
you like.
Regards,
Greg Young - Houston (DWH)
RV-6 N6GY ...project Phoenix
Navion N5221K - just an XXL RV-6A
> To all,
>
> Hypothetically, let's say I'm going to have two types of airspeed
> indicators in my aircraft, for redundancy of course. I am
> considering the Blue Mountain EFIS, but also want a mechanical backup
> in case Murphy stows away. The first question is "Does Blue Mountain
> require a specific pitot tube, their own, probably?". But this is
> not why I'm writing. For arguments sake, let's assume that it can
> utilize a normal pitot tube, would it be possible to split the pitot
> feed to go to two different ports (two different instruments, i.e. BM
> EFIS, and a normal mechanical airspeed indicator)? I understand
> static air is static air....But, wouldn't a split in a ram-air-
> pressure source effectively halve the pressure in the system to the
> different guages? Would two pitot tubes be required?
>
> Thanks,
> Eric
[Non-text portions of this message have been removed]
Author: "William Slaughter" <willslau@...> Time: Thu May 30, 2002 4:24 pm PDT Link
Eric,
The ram air pressure system is dead-heading against the instrument(s) and
will thus equalize in the two lines. There isn't any real flow going on.
William
-----Original Message-----
From: gingy1raylynn [mailto:gingy1@b...]
Sent: Thursday, May 30, 2002 2:50 PM
To: vansairforce@yahoogroups.com
Subject: [VAF Mailing List] Pitot-Static question
To all,
Hypothetically, let's say I'm going to have two types of airspeed
indicators in my aircraft, for redundancy of course. I am
considering the Blue Mountain EFIS, but also want a mechanical backup
in case Murphy stows away. The first question is "Does Blue Mountain
require a specific pitot tube, their own, probably?". But this is
not why I'm writing. For arguments sake, let's assume that it can
utilize a normal pitot tube, would it be possible to split the pitot
feed to go to two different ports (two different instruments, i.e. BM
EFIS, and a normal mechanical airspeed indicator)? I understand
static air is static air....But, wouldn't a split in a ram-air-
pressure source effectively halve the pressure in the system to the
different guages? Would two pitot tubes be required?
Thanks,
Eric
Online help on this group at:
http://help.yahoo.com/help/groups/
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Non-text portions of this message have been removed]
Author: "mustaiks" <mustaiks@...> Time: Thu May 30, 2002 4:24 pm PDT Link
The two airspeed indicators can work from the same pitot
souce. The ram pressure in the tube is constant. Since the tube
is sealed without any holes other than the pitot tube inlet, the
length and size of the tube or the number of pressure gauges
will not effect readings.
Pressure is pressure, and pressure guages do not lower it.
Steve Mustaikis
--- In vansairforce@y..., "gingy1raylynn" <gingy1@b...> wrote:
> To all,
>
> Hypothetically, let's say I'm going to have two types of airspeed
> indicators in my aircraft, for redundancy of course. I am
> considering the Blue Mountain EFIS, but also want a
mechanical backup
> in case Murphy stows away. The first question is "Does Blue
Mountain
> require a specific pitot tube, their own, probably?". But this is
> not why I'm writing. For arguments sake, let's assume that it
can
> utilize a normal pitot tube, would it be possible to split the pitot
> feed to go to two different ports (two different instruments, i.e.
BM
> EFIS, and a normal mechanical airspeed indicator)? I
understand
> static air is static air....But, wouldn't a split in a ram-air-
> pressure source effectively halve the pressure in the system to
the
> different guages? Would two pitot tubes be required?
>
> Thanks,
> Eric
Author: Nathaniel Perlman <nhperlman@...> Time: Thu May 30, 2002 4:24 pm PDT Link
Two pitot tubes would be the way to go. If you still only had one tube, what do you do when when it gets blocked? Redundancy would mean two seperate, independent systems.
Nate, RV-8 - working on the tale
gingy1raylynn <gingy1@b...> wrote: To all,
Hypothetically, let's say I'm going to have two types of airspeed
indicators in my aircraft, for redundancy of course. I am
considering the Blue Mountain EFIS, but also want a mechanical backup
in case Murphy stows away. The first question is "Does Blue Mountain
require a specific pitot tube, their own, probably?". But this is
not why I'm writing. For arguments sake, let's assume that it can
utilize a normal pitot tube, would it be possible to split the pitot
feed to go to two different ports (two different instruments, i.e. BM
EFIS, and a normal mechanical airspeed indicator)? I understand
static air is static air....But, wouldn't a split in a ram-air-
pressure source effectively halve the pressure in the system to the
different guages? Would two pitot tubes be required?
Thanks,
Eric
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[Non-text portions of this message have been removed]
Author: "Steve Raddatz" <raddatz@...> Time: Fri May 31, 2002 7:24 pm PDT Link
Only one pitot tube is needed, all you do is tee the line ( make sure there
are no leaks ) because the air speed gauges are basically pressure gauges
and use no air for working.-----Original Message-----
From: gingy1raylynn [mailto:gingy1@b...]
Sent: Thursday, May 30, 2002 2:50 PM
To: vansairforce@yahoogroups.com
Subject: [VAF Mailing List] Pitot-Static question
To all,
Hypothetically, let's say I'm going to have two types of airspeed
indicators in my aircraft, for redundancy of course. I am
considering the Blue Mountain EFIS, but also want a mechanical backup
in case Murphy stows away. The first question is "Does Blue Mountain
require a specific pitot tube, their own, probably?". But this is
not why I'm writing. For arguments sake, let's assume that it can
utilize a normal pitot tube, would it be possible to split the pitot
feed to go to two different ports (two different instruments, i.e. BM
EFIS, and a normal mechanical airspeed indicator)? I understand
static air is static air....But, wouldn't a split in a ram-air-
pressure source effectively halve the pressure in the system to the
different guages? Would two pitot tubes be required?
Thanks,
Eric
Online help on this group at:
http://help.yahoo.com/help/groups/
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Non-text portions of this message have been removed]
Author: "enewton57" <enewton57@...> Time: Sun Jun 2, 2002 1:27 pm PDT Link
Hi Eric,
If you want true redundancy, you will need two pitot tubes. Pitot
system is a failure point as it can get plugged (mud daubers, etc.)
or a line can come loose. It will work fine to split the line on a
single one, but you wont have true redundancy (if that's what you are
striving for.
Personally, I would stick with just one pitot tube anyway. I rarely
pay any attention to my airspeed indicator except during takeoff and
landing. During cruise, I watch GPS ground speed.
I have thought recently about what would happen if I lost my airspeed
indicator. I find that I really rely on it during my landing
approach as it is hard judge by ground speed as the wind varies so
much. I glance at it frequently during the entire final approach
keeping it on a steady 80 mph. What would I do if it failed?
I have been recently working on getting the sight picture (RPM and
horizon spot on the windshield) during landing approach. I practice
this with a spotter pilot in the plane and I attempt to land without
looking at my airspeed indicator. I have pretty much got it down now
but I still vary somewhat. Thats my redundancy for the airspeed
indicator. I could land without it if needed.
Hope this helps some,
Eric Newton - Long Beach, MS
RV-6A - N57ME (Just back from Waco fly-in)
www.ericsrv6a.com
--- In vansairforce@y..., "gingy1raylynn" <gingy1@b...> wrote:
> To all,
>
> Hypothetically, let's say I'm going to have two types of airspeed
> indicators in my aircraft, for redundancy of course. I am
> considering the Blue Mountain EFIS, but also want a mechanical
backup
> in case Murphy stows away. The first question is "Does Blue
Mountain
> require a specific pitot tube, their own, probably?". But this is
> not why I'm writing. For arguments sake, let's assume that it can
> utilize a normal pitot tube, would it be possible to split the
pitot
> feed to go to two different ports (two different instruments, i.e.
BM
> EFIS, and a normal mechanical airspeed indicator)? I understand
> static air is static air....But, wouldn't a split in a ram-air-
> pressure source effectively halve the pressure in the system to the
> different guages? Would two pitot tubes be required?
>
> Thanks,
> Eric
Author: "Ross Hauck" <ross@...> Time: Mon Jun 3, 2002 5:25 am PDT Link
My configuration will include the Blue Mtn. EFIS (which does work with a
std pitot) and a Lift Reserve Indicator. This does give complete
redundancy. Further, it indicates stall speed at any weight or cg
config. The LRI has its own "pitot," with two ports giving differential
pressure indicating angle of attack. See www.liftreserve.com
<http://www.liftreserve.com/>
Ross
--- In vansairforce@y..., "gingy1raylynn" <gingy1@b...> wrote:
> To all,
> Hypothetically, let's say I'm going to have two types of airspeed
> indicators in my aircraft, for redundancy of course. I am
> considering the Blue Mountain EFIS, but also want a mechanical
backup
> in case Murphy stows away. The first question is "Does Blue
Mountain
> require a specific pitot tube, their own, probably?". But this is
> not why I'm writing. For arguments sake, let's assume that it can
> utilize a normal pitot tube, would it be possible to split the
pitot
> feed to go to two different ports (two different instruments, i.e.
BM
> EFIS, and a normal mechanical airspeed indicator)? I understand
> static air is static air....But, wouldn't a split in a ram-air-
> pressure source effectively halve the pressure in the system to the
> different guages? Would two pitot tubes be required?
>
> Thanks,
> Eric
Online help on this group at:
http://help.yahoo.com/help/groups/
Your use of Yahoo! Groups is subject to the Yahoo!
<http://docs.yahoo.com/info/terms/> Terms of Service.
[Non-text portions of this message have been removed]
Author: "Phil Birkelbach" <phil@...> Time: Mon Jun 3, 2002 9:13 am PDT Link
When I was learning to fly sailplanes as a kid my instructor was adament
about me developing the skill to land the glider without ANY instruments.
Of course you only have a few to start with, but he would have me cover my
ASI and Altimeter once I started on my downwind and use only the sound of
the slipstream, the attitude of the plane and my own judgement as to what my
altitude and airspeed was. I don't think his reasoning was to prepare me
for instrument failure but to increase my landing skills. There ain't no
'go-arounds' in a glider. Obviously this is an easier thing to do in a
glider because for one you can hear the air whizzing by. A 2-33 is a very
quiet place right before it stalls. :-) Without an engine or flaps your
horizon reference is constant too so I will admit it is much easier, but I
intend to spend a lot of time getting used to landing without the ASI and or
Altimeter in my -7 once it is built. (with a safety-pilot of course) I
think that it is a good skill to have and it eliminates any requirement for
redundant instruments for VFR flight.
Just my opinion and it is worth exactly what you paid for it.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved)
http://www.myrv7.com
Fuselage
Airplanes never win battles with the ground. The best the airplane can hope
for is a draw.
----- Original Message -----
From: "enewton57" <enewton57@y...>
To: <vansairforce@yahoogroups.com>
Sent: Sunday, June 02, 2002 8:32 AM
Subject: [VAF Mailing List] Re: Pitot-Static question
> Hi Eric,
> If you want true redundancy, you will need two pitot tubes. Pitot
> system is a failure point as it can get plugged (mud daubers, etc.)
> or a line can come loose. It will work fine to split the line on a
> single one, but you wont have true redundancy (if that's what you are
> striving for.
>
> Personally, I would stick with just one pitot tube anyway. I rarely
> pay any attention to my airspeed indicator except during takeoff and
> landing. During cruise, I watch GPS ground speed.
>
> I have thought recently about what would happen if I lost my airspeed
> indicator. I find that I really rely on it during my landing
> approach as it is hard judge by ground speed as the wind varies so
> much. I glance at it frequently during the entire final approach
> keeping it on a steady 80 mph. What would I do if it failed?
>
> I have been recently working on getting the sight picture (RPM and
> horizon spot on the windshield) during landing approach. I practice
> this with a spotter pilot in the plane and I attempt to land without
> looking at my airspeed indicator. I have pretty much got it down now
> but I still vary somewhat. Thats my redundancy for the airspeed
> indicator. I could land without it if needed.
>
> Hope this helps some,
>
> Eric Newton - Long Beach, MS
> RV-6A - N57ME (Just back from Waco fly-in)
> www.ericsrv6a.com
>
> --- In vansairforce@y..., "gingy1raylynn" <gingy1@b...> wrote:
> > To all,
> >
> > Hypothetically, let's say I'm going to have two types of airspeed
> > indicators in my aircraft, for redundancy of course. I am
> > considering the Blue Mountain EFIS, but also want a mechanical
> backup
> > in case Murphy stows away. The first question is "Does Blue
> Mountain
> > require a specific pitot tube, their own, probably?". But this is
> > not why I'm writing. For arguments sake, let's assume that it can
> > utilize a normal pitot tube, would it be possible to split the
> pitot
> > feed to go to two different ports (two different instruments, i.e.
> BM
> > EFIS, and a normal mechanical airspeed indicator)? I understand
> > static air is static air....But, wouldn't a split in a ram-air-
> > pressure source effectively halve the pressure in the system to the
> > different guages? Would two pitot tubes be required?
> >
> > Thanks,
> > Eric
> Online help on this group at:
> http://help.yahoo.com/help/groups/
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/