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LRI gauge

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taffy0687(at)yahoo.com
Guest

Posted: Fri Mar 16, 2007 5:58 pm Post subject: LRI gauge

Folks,

   

  I just ordered my LRI gauge for $11.95, they still have 715 left.(see link below).

  [url=http://www.surpluscenter.com/item.asp?UID 07031616355052&item 1-1623&catname]http://www.surpluscenter.com/item.asp?UID 07031616355052&item 1-1623&catname[/url]=   

   

  I wished I'd had known about it when I had my 701, I just couldn't get use to that slow landing speed.    

   

  Thanks for the info,

  Fritz  601XL, Corvair, 90/90    scratch builder



    Don't get soaked.  Take a[url= http://tools.search.yahoo.com/shortcuts/?fr=oni_on_mail&#news] quick peek at the forecast [/url]

 with the[url= http://tools.search.yahoo.com/shortcuts/?fr=oni_on_mail&#news]Yahoo! Search weather shortcut.[/url] [quote][b]

dpfisher(at)scottsbluff.n
Guest

Posted: Sun Mar 18, 2007 11:42 am Post subject: LRI gauge

OK guys,



  I give , if the LRI gauge is an air pressure instrument, what makes it 

different from an airspeed indicator??

Dave, 701 with A-80-8 Continental

taffy0687(at)yahoo.com
Guest

Posted: Sun Mar 18, 2007 1:10 pm Post subject: LRI gauge

[quote][b]

jetboy

Joined: 22 Jul 2006
Posts: 233

Posted: Sun Mar 18, 2007 1:43 pm Post subject: Re: LRI gauge

The LRI is not just ram air pressure like an ASI.  Readings are derived from the difference in pressure between different surfaces in the airflow. The ports are either in the upper and lower wing surfaces or in a probe that is oriented in a similar way, and adjusted to respond at the correct angle of attack.



There is some further description at the site that supplies them, or at 

http://www.ch601.org/resources/aoa/aoa.htm  



I have not got one on my 701 yet, and following the discussion threads I'm still not decided on whether the instruments should be further complicated. What interests me is the difference in readings with flap / without flap, as this aspect would need to be consistent with both configurations, TO and landing, to be a reliable indicator for me.



After 170 hrs in the 701 I still find things unravel very fast at critical times and there is a lot of body language required in adjusting power / angle without time for looking at instruments or interpreting their meaning dependant on load / configuration. So I tend to favour the view, that for the 701, the seat of the pants will remain the primary indicator.



Ralph

_________________
Ralph - CH701 / 2200a

Terry Phillips

Joined: 11 Jan 2006
Posts: 346
Location: Corvallis, MT

Posted: Sun Mar 18, 2007 2:27 pm Post subject: LRI gauge

I'll take a stab at this.



Both the ASI and the LRI are differential pressure gages, i.e., they 

measure the difference in pressure between the two pressure taps on the gage.



The difference between the ASI and the LRI is in the location of the 

pressure ports connected to the gage's pressure taps, and in the markings 

on the face of each gage.



One ASI pressure tap is connected to the ram air port in the pitot (which 

attempts to point directly into the relative wind); the other tap is 

connected to the static air port which attempts to be normal to the 

relative wind. If the pitot is directly into the relative wind, and the 

static is normal to the relative wind, then there is a simple relationship 

between the difference in pressure and the air speed. Bernoulli's law 

applies here. When the pitot is not pointing into the relative wind (think 

slow flight with a high angle of attack) or the static port is not normal 

to the relative wind (think forward slip to a landing) then there will be 

an error in the indicated air speed. That's why your Cessna 150 POH has a 

table that relates indicated air speed to calibrated air speed. I think 

they design the ASI so that the error is in your favor--i.e., the indicated 

air speed suggests you are closer to a stall than you actually are. The 

markings on the face of the ASI gage just graphically calculate the air 

speed for the variation in the measured differential pressure between the 

pitot and static.



The LRI pressure taps are connected to holes on two angled faces of the LRI 

probe. The pressure from these two ports is related to each of the port's 

angle with the relative wind. I.e., the closer a port is to directly into 

the relative wind, the greater the pressure the port will see. As the angle 

of the attack of the aircraft changes, the angles that each of these ports 

makes with the relative wind also changes. If it is all designed and 

adjusted properly, there should be a 1 to 1 relationship between the 

measured differential pressure and the angle of attack. So, you can mark 

the face of the LRI to indicate how close you are the critical angle of 

attack, i.e., the angle of attack at stall, typically about 18 degrees.



'Hope that helps.



Terry

At 01:01 PM 3/18/2007 -0700, you wrote:

 	  Quote: 	
		  OK guys,



  I give , if the LRI gauge is an air pressure instrument, what makes it 

 different from an airspeed indicator??

Dave, 701 with A-80-8 Continental


	


Terry Phillips

ttp44~at~rkymtn.net

Corvallis MT

Just starting a 601 kit

_________________
Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Tail feathers done; working on the wings.

taffy0687(at)yahoo.com
Guest

Posted: Sun Mar 18, 2007 4:21 pm Post subject: LRI gauge

SEE BELOW FOR MESSAGE----- IT WAS BLANK ON THE FIRST ATTEMPT---- this is the second try.



  Big Gee <taffy0687(at)yahoo.com> wrote:

  [quote]  Dave,

  I think you'll find the link below very informative.

  Fritz

   

  http://www.liftreserve.com/



Dave and Pam Fisher <dpfisher(at)scottsbluff.net> wrote:

   	  Quote: 	
		  --> Zenith-List message posted by: Dave and Pam Fisher 



OK guys,



I give , if the LRI gauge is an air pressure instrument, what makes it 

different from an airspeed indicator??

Dave, 701 with A-80-8  href="http://answers.yahoo.com/dir/index;_ylc=X3oDMTFvbGNhMGE3BF9TAzM5NjU0NTEwOARfcwMzOTY1NDUxMDMEc2VjA21haWxfdGFnbGluZQRzbGsDbWFpbF90YWcx?link=ask&sid=396546091">great tips from Yahoo! Answers users.

	




   [quote][b]

grs-pms(at)comcast.net
Guest

Posted: Sun Mar 18, 2007 5:21 pm Post subject: LRI gauge

The air speed indicator measures the pressure difference between  the free

stream and the static source, which (ideally)

 is not affected by speed. This difference is, however, affected by the

density of the air, so true airspeed varies from indicated airspeed with

temperature and altitude.  The LRI measures differential pressure between a

pair of ports with different alignments to the free stream.  This pressure

varies with angle of attack, hence with varying lift coefficients.   This

difference does not vary with density, so the lift reserve or stall margin

is accurately indicated at every temperature, altitude and aircraft weight,

once the LRI is properly calibrated.



George

---

dpfisher(at)scottsbluff.n
Guest

Posted: Mon Mar 19, 2007 8:31 pm Post subject: LRI gauge

Hi,



Thanks for the explanations everyone - makes sense now!!



Dave, 701, do not archive

jd(at)lawsonimaging.ca
Guest

Posted: Tue Mar 20, 2007 1:34 pm Post subject: lri gauge

Greetings...



Thanks to advice on this list, I just received a Dwyer 5000 

gage from

Surplus Center. Thanks for passing that tidbit along!



Question: is there a trick to disassembling the gage to 

replace (or

cover) the stock face with the new LRI face. And thanks, 

too, to the

lister who posted the nice colour faceplate files!



john butterfield wrote:

 	  Quote: 	
		   

 

 hi list

 i looked up doug naylor's suggestion and ordered a

 guage at 12.00 plus shipping. a total of about 22.00. 

 a really good deal.

 

 i also have the probe from from scott laughlin and its

 a fine piece of work.  for about 85.00 you can have a

 first rate aoa system totally self sufficient from

 electric power.  again, please look into this system

 as it will make your flying easier  and may save your

 life

 thanks for the tip doug

 john butterfield

 601XL, corvair

 torrance, ca

 

 


	


-- 

Regards,  J.



flying:   Zenith STOL CH701/912 C-IGGY, 350 hrs.

building: Sonex #325, Jabiru 3300/6, 85% completed



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

J. Davis, M.Sc. (computer science)

*NIX consulting, SysAdmin

email: jd at lawsonimaging.ca

voice: 519.289.1527 http://www.cleco.ca

c/o Brandywine Aviation 5507 Irish Dr., Appin, ON

N42 47.33  W081 36.50 31/13 2000+ x 60', elev: 740'

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



To most people the sky is the limit.

To those who love aviation, the sky is home.



Improve your performance by improving your attitude.

dbortol

Joined: 02 Sep 2006
Posts: 46

Posted: Tue Mar 20, 2007 2:05 pm Post subject: lri gauge

It's very easy, but it will be tight the first time. Hold the body of

the gauge in one hand. Palm the face of the gauge with the other hand

and rotate to the left.

On 3/20/07, j. davis <jd(at)lawsonimaging.ca> wrote:

 	  Quote: 	

 Greetings...

 Thanks to advice on this list, I just received a Dwyer 5000

 gage from

 Surplus Center. Thanks for passing that tidbit along!

 Question: is there a trick to disassembling the gage to

 replace (or

 cover) the stock face with the new LRI face. And thanks,

 too, to the

 lister who posted the nice colour faceplate files!

 john butterfield wrote:

 > 

 <jdbutterfield(at)yahoo.com>

 >

 > hi list

 > i looked up doug naylor's suggestion and ordered a

 > guage at 12.00 plus shipping. a total of about 22.00.

 > a really good deal.

 >

 > i also have the probe from from scott laughlin and its

 > a fine piece of work.  for about 85.00 you can have a

 > first rate aoa system totally self sufficient from

 > electric power.  again, please look into this system

 > as it will make your flying easier  and may save your

 > life

 > thanks for the tip doug

 > john butterfield

 > 601XL, corvair

 > torrance, ca

 >

 >

 --

 Regards,  J.

 flying:   Zenith STOL CH701/912 C-IGGY, 350 hrs.

 building: Sonex #325, Jabiru 3300/6, 85% completed

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

 J. Davis, M.Sc. (computer science)

 *NIX consulting, SysAdmin

 email: jd at lawsonimaging.ca

 voice: 519.289.1527 http://www.cleco.ca

 c/o Brandywine Aviation 5507 Irish Dr., Appin, ON

 N42 47.33  W081 36.50 31/13 2000+ x 60', elev: 740'

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

 To most people the sky is the limit.

 To those who love aviation, the sky is home.

 Improve your performance by improving your attitude.

jd(at)lawsonimaging.ca
Guest

Posted: Tue Mar 20, 2007 3:15 pm Post subject: lri gauge

Thanks! Worked like a charm. I used a couple of non-skid 

mats I had

lying around. One to hold the gage, the other to turn the bezel.

Thanks also to 'CH701 (701stol)', who responded to me 

personally!



Now: has anyone calibrated the needle? My panel is at an 

angle, and the needle

doesn't quite 'zero'. My guess is that the two little 

phillips head screws

at twelve o'clock will adjust the pressure on the diaphragm, 

but I'm

just guessing. There's also a brass nut dead centre...



Dino wrote:

 	  Quote: 	
		   

 It's very easy, but it will be tight the first time. Hold the body of

 the gauge in one hand. Palm the face of the gauge with the other hand

 and rotate to the left.

 

 On 3/20/07, j. davis <jd(at)lawsonimaging.ca> wrote:

> 

>

> Greetings...

>

> Thanks to advice on this list, I just received a Dwyer 5000

> gage from

> Surplus Center. Thanks for passing that tidbit along!

>

> Question: is there a trick to disassembling the gage to

> replace (or

> cover) the stock face with the new LRI face. And thanks,

> too, to the

> lister who posted the nice colour faceplate files!

>

> john butterfield wrote:

> > 

> <jdbutterfield(at)yahoo.com>

> >

> > hi list

> > i looked up doug naylor's suggestion and ordered a

> > guage at 12.00 plus shipping. a total of about 22.00.

> > a really good deal.

> >

> > i also have the probe from from scott laughlin and its

> > a fine piece of work.  for about 85.00 you can have a

> > first rate aoa system totally self sufficient from

> > electric power.  again, please look into this system

> > as it will make your flying easier  and may save your

> > life

> > thanks for the tip doug

> > john butterfield

> > 601XL, corvair

> > torrance, ca

> >

> >

>

> -- 

> Regards,  J.

>

> flying:   Zenith STOL CH701/912 C-IGGY, 350 hrs.

> building: Sonex #325, Jabiru 3300/6, 85% completed

>

> -------------------------------------------------

> J. Davis, M.Sc. (computer science)

> *NIX consulting, SysAdmin

> email: jd at lawsonimaging.ca

> voice: 519.289.1527 http://www.cleco.ca

> c/o Brandywine Aviation 5507 Irish Dr., Appin, ON

> N42 47.33  W081 36.50 31/13 2000+ x 60', elev: 740'

> -------------------------------------------------

>

> To most people the sky is the limit.

> To those who love aviation, the sky is home.

>

> Improve your performance by improving your attitude.

 

 

 

 


	


-- 

Regards,  J.



flying:   Zenith STOL CH701/912 C-IGGY, 350 hrs.

building: Sonex #325, Jabiru 3300/6, 85% completed



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

J. Davis, M.Sc. (computer science)

*NIX consulting, SysAdmin

email: jd at lawsonimaging.ca

voice: 519.289.1527 http://www.cleco.ca

c/o Brandywine Aviation 5507 Irish Dr., Appin, ON

N42 47.33  W081 36.50 31/13 2000+ x 60', elev: 740'

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



To most people the sky is the limit.

To those who love aviation, the sky is home.



Winners do what losers don't want to do.

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