Sparrow Strainers - Why and Why Not?


Corbin
 

Help educate me on this old topic. I understand what they do regarding pitch, however, why do some of us not have them? Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR


Jay Scheevel
 

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





Corbin
 

Good info....thanks Jay.

Corbin

On July 26, 2020 at 7:04 AM, Jay Scheevel <jay@...> wrote:

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR







--

Corbin 
N33QR


Jerry Marstall <jnmarstall@...>
 

DO NOT fly without them.

-------- Original message --------
From: Jay Scheevel <jay@...>
Date: 7/26/20 8:04 AM (GMT-05:00)
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





Martin Skiby
 



Martin

 


On Jul 26, 2020, at 5:07 AM, Corbin via groups.io <c_geiser@...> wrote:


Good info....thanks Jay.

Corbin

On July 26, 2020 at 7:04 AM, Jay Scheevel <jay@...> wrote:

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR







--

Corbin 
N33QR


Martin Skiby
 

Well said Jerry.

Martin

 


On Jul 26, 2020, at 5:04 AM, Jay Scheevel <jay@...> wrote:


The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





Michael Dunning
 
Edited

You nailed it, it's a GU vs LS1 thing. 

Just one of several reasons the LS1 is a pretty garbage airfoil. Turns out that when used in an area with a control surface the elevator/aileron portion will "float" upwards and dump lift. The sparrow strainer is simply a fixed trim tab to prevent that from happening, at the cost of some drag, just as Jay said.

--
-MD
#2827 (still thinking about planning on visualizing how to finish building)


Corbin
 

Awesome.  Thanks.  I’m glad to have the GU canard and no sparrow strainer.

Corbin

On Jul 26, 2020, at 9:38 AM, Michael <dunningme@...> wrote:



[Edited Message Follows]

You nailed it, it's a GU vs LS1 thing. 

Just one of several reasons the LS1 is a pretty garbage airfoil. Turns out that when used in an area with a control surface the elevator/aileron portion will "float" upwards and dump lift. The sparrow strainer is simply a fixed trim tab to prevent that from happening, at the cost of some drag, just as Jay said.

--
-MD
#2827 (still thinking about planning on visualizing how to finish building)

--

Corbin 
N33QR


Jim Patillo
 

Corbin,

While the GU canard is a decent canard it had the issues all GU’s have. They are useless in rain or bugs without VG’s as I said to you way back. The LS1 canard is much more forgiving and doesn’t change its lift characteristics with rain or bugs on them. Contrary to an opinion stated earlier, the LS1 is not a garbage airfoil or a band aid. One should fly both wings before spewing off about them.

The “sparrow strainers” were added because of the increased speed of the 0200 as I understood it, to keep the stick forces lower and to prevent a high speed tuck.

Jerry is very correct. Don’t fly the LS1 without the sparrow strainers or you will have a bad day. VG’s are the band aid in my opinion. Just sayin’

Jim Patillo

N46JP Q200
1750 hours on my LS1 airframe

Sent from Outer Space


From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jerry Marstall <jnmarstall@...>
Sent: Sunday, July 26, 2020 5:15:52 AM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?
 
DO NOT fly without them.

-------- Original message --------
From: Jay Scheevel <jay@...>
Date: 7/26/20 8:04 AM (GMT-05:00)
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





Bruce Crain
 

LS1 gotta have em. GU I understand doesn’t. You might not be able to hold on to the stick without the LS1 strainers. Really heavy pressure forward. In fact if the strainers are not dialed in it will have a lot of pressure also.
Bruce
On Jul 26, 2020, at 5:15 AM, Corbin via groups.io <c_geiser=icloud.com@groups.io> wrote:

Help educate me on this old topic. I understand what they do regarding pitch, however, why do some of us not have them? Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR



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Corbin
 

Thanks Jim.  Oh and if I forgot to update on the VG’s on my GU, I did place them back on and even added a few more on each side.  The new ones are white and blend in a bit better than the metal ones I had on before.

Corbin

On Jul 26, 2020, at 1:43 PM, Jim Patillo <Logistics_engineering@...> wrote:


Corbin,

While the GU canard is a decent canard it had the issues all GU’s have. They are useless in rain or bugs without VG’s as I said to you way back. The LS1 canard is much more forgiving and doesn’t change its lift characteristics with rain or bugs on them. Contrary to an opinion stated earlier, the LS1 is not a garbage airfoil or a band aid. One should fly both wings before spewing off about them.

The “sparrow strainers” were added because of the increased speed of the 0200 as I understood it, to keep the stick forces lower and to prevent a high speed tuck.

Jerry is very correct. Don’t fly the LS1 without the sparrow strainers or you will have a bad day. VG’s are the band aid in my opinion. Just sayin’

Jim Patillo

N46JP Q200
1750 hours on my LS1 airframe

Sent from Outer Space

From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jerry Marstall <jnmarstall@...>
Sent: Sunday, July 26, 2020 5:15:52 AM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?
 
DO NOT fly without them.

-------- Original message --------
From: Jay Scheevel <jay@...>
Date: 7/26/20 8:04 AM (GMT-05:00)
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





--

Corbin 
N33QR


Dan Thomas
 

Question:  So if the GU airfoil needs VG‘s that cause a little extra drag and the LS-1 needs sparrow strainers that cause a little extra drag, which configuration has the least amount of drag overall?

—Dan T.




On Sunday, July 26, 2020, 12:01 PM, Corbin via groups.io <c_geiser@...> wrote:

Thanks Jim.  Oh and if I forgot to update on the VG’s on my GU, I did place them back on and even added a few more on each side.  The new ones are white and blend in a bit better than the metal ones I had on before.

Corbin

On Jul 26, 2020, at 1:43 PM, Jim Patillo <Logistics_engineering@...> wrote:


Corbin,

While the GU canard is a decent canard it had the issues all GU’s have. They are useless in rain or bugs without VG’s as I said to you way back. The LS1 canard is much more forgiving and doesn’t change its lift characteristics with rain or bugs on them. Contrary to an opinion stated earlier, the LS1 is not a garbage airfoil or a band aid. One should fly both wings before spewing off about them.

The “sparrow strainers” were added because of the increased speed of the 0200 as I understood it, to keep the stick forces lower and to prevent a high speed tuck.

Jerry is very correct. Don’t fly the LS1 without the sparrow strainers or you will have a bad day. VG’s are the band aid in my opinion. Just sayin’

Jim Patillo

N46JP Q200
1750 hours on my LS1 airframe

Sent from Outer Space

From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jerry Marstall <jnmarstall@...>
Sent: Sunday, July 26, 2020 5:15:52 AM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?
 
DO NOT fly without them.

-------- Original message --------
From: Jay Scheevel <jay@...>
Date: 7/26/20 8:04 AM (GMT-05:00)
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





--

Corbin 
N33QR


Michael Dunning
 

Corbin,
 
There is a great two part series in the Dragonfly newsletter titled "Canard Contamination" that covers the history of this subject along with the GU and VGs in-depth. Sadly, determining the number and location of VGs still seems to be a black art lacking procedure; Looking forward to your continued results.

Canard Contamination - Part I

Canard Contamination - Part II

As Jim correctly pointed out, my comments earlier were about the LS1 as an airfoil, not the Q200 as a wing. The fix for both VGs and sparrow strainers probably lies in what the Long EZ did in 1985 with the R1145MS but by then it was too late for QAC.

From Wikipedia:

"In January 1985, it was announced that plans for a new canard were being offered, to eliminate "rain trim change" that had been experienced by Long-EZ pilots.[5] This trim change is usually a nose down trim change experienced when flying into rain requiring a small aft force on the stick to maintain altitude, which is easily trimmed out, using the bungee trim system. The new canard was designed with the Roncz R1145MS airfoil, which produces considerably more lift than the original GU25-5(11)8 airfoil. This enabled the new canard to be designed with less span, reducing wetted area and thus drag. The new canard has a negligible rain trim and the rain only adds 2 knots to the stall speed."


--
-MD
#2827 (still thinking about planning on visualizing how to finish building)


Richard Thomson
 

So with the LS1 canard, how much relief does reflex provide from the stick pressure with sparrow strainers in the inboard position ?

Rich T.

On 26/07/2020 13:04, Jay Scheevel wrote:
The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





Robert Cringely
 

The GA(W)-2 airfoil used on the original Glasairs had such a cusped trailing edge, one result of which was an unpleasant stiffening of ailerons at high speeds. You see this, too, in a production P-51, though NOT in the EAA's XP-51 prototype, which lacks the cusps and has light ailerons at all speeds. Yes, I know the P-51 didn't have a GA(W)-2 airfoil, but its (different) laminar flow airfoil showed the same characteristics.

On the Glasairs, Lyle Powell was the original builder to fill-in the cusps on his Glasair ailerons, lightening them up. Lyle also built the first fixed tricycle Glasair and did the original wingtip extensions. Lyle, who is gone now, was quite the experimenter as well as being the father-in-law of CAFE Foundation founder Brien Seeley.

On the Glasair III, II, IIs, etc., Stoddard-Hamilton took the cusp out of the factory molds when Lyle showed them that there really wasn't any performance downside to doing so. Only the original prototype Glasair III, for example, ever had cusps (later filled-in). It also flew 2000+ hours without a carbon fiber horizontal stabilizer.

I built Glasair #102 (the first kit) and #123 and eventually de-cusped both. I would suggest doing the same with the LS1 on any Quickie and eliminate the sparrow strainers entirely.

Bob Cringely


On Sun, Jul 26, 2020 at 5:04 AM Jay Scheevel <jay@...> wrote:
The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser=icloud.com@groups.io> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





Jim Patillo
 

My gut reaction is the GU has a bit less drag ( without VG’s) and therefore produces 2-3 more miles per hour with a pumped 0200 attached, same rpms and same size props. I’ve flown with both.

BTW Corbin, we refer to the brass weight on your tail spring as an RV lure, cause that’s what they will be looking at. Mark Summers coined that one. Ha Ha.

Jim
N46JP - Q200

Sent from Outer Space


From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Dan Thomas via groups.io <rv6dan@...>
Sent: Sunday, July 26, 2020 1:37:28 PM
To: main@Q-List.groups.io <main@Q-List.groups.io>; main@q-list.groups.io <main@q-list.groups.io>
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?
 
Question:  So if the GU airfoil needs VG‘s that cause a little extra drag and the LS-1 needs sparrow strainers that cause a little extra drag, which configuration has the least amount of drag overall?

—Dan T.




On Sunday, July 26, 2020, 12:01 PM, Corbin via groups.io <c_geiser@...> wrote:

Thanks Jim.  Oh and if I forgot to update on the VG’s on my GU, I did place them back on and even added a few more on each side.  The new ones are white and blend in a bit better than the metal ones I had on before.

Corbin

On Jul 26, 2020, at 1:43 PM, Jim Patillo <Logistics_engineering@...> wrote:


Corbin,

While the GU canard is a decent canard it had the issues all GU’s have. They are useless in rain or bugs without VG’s as I said to you way back. The LS1 canard is much more forgiving and doesn’t change its lift characteristics with rain or bugs on them. Contrary to an opinion stated earlier, the LS1 is not a garbage airfoil or a band aid. One should fly both wings before spewing off about them.

The “sparrow strainers” were added because of the increased speed of the 0200 as I understood it, to keep the stick forces lower and to prevent a high speed tuck.

Jerry is very correct. Don’t fly the LS1 without the sparrow strainers or you will have a bad day. VG’s are the band aid in my opinion. Just sayin’

Jim Patillo

N46JP Q200
1750 hours on my LS1 airframe

Sent from Outer Space

From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jerry Marstall <jnmarstall@...>
Sent: Sunday, July 26, 2020 5:15:52 AM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?
 
DO NOT fly without them.

-------- Original message --------
From: Jay Scheevel <jay@...>
Date: 7/26/20 8:04 AM (GMT-05:00)
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

Cheers,
Jay

Sent from my Verizon Wireless 4G LTE DROID


"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR





--

Corbin 
N33QR


Jay Scheevel
 

Hi Jim,

 

The shape and resulting pressure distribution on the LS1 is the entire reason you need the sparrow strainers on the LS1, not because of speed. I agree with you about the resistance to contamination of the LS1 vs. the GU. As it turns out the LS1 also benefits from the addition of VG’s, but they are not required. I am posting a research paper on this subject in the files section.

 

This would be a good topic for Dr. Shuk to weigh in on at the FOD…hint..hint.

 

BTW. I have designed an elevator that could be retrofit to the LS1 in place of the original that would not require the sparrow strainers and would not change the flight characteristics significantly of the LS1 significantly. I will build and test it some day.

 

Cheers,

Jay

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Jim Patillo
Sent: Sunday, July 26, 2020 12:43 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

 

Corbin,

 

While the GU canard is a decent canard it had the issues all GU’s have. They are useless in rain or bugs without VG’s as I said to you way back. The LS1 canard is much more forgiving and doesn’t change its lift characteristics with rain or bugs on them. Contrary to an opinion stated earlier, the LS1 is not a garbage airfoil or a band aid. One should fly both wings before spewing off about them.

 

The “sparrow strainers” were added because of the increased speed of the 0200 as I understood it, to keep the stick forces lower and to prevent a high speed tuck.

 

Jerry is very correct. Don’t fly the LS1 without the sparrow strainers or you will have a bad day. VG’s are the band aid in my opinion. Just sayin’

 

Jim Patillo

 

N46JP Q200

1750 hours on my LS1 airframe

 

Sent from Outer Space


From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jerry Marstall <jnmarstall@...>
Sent: Sunday, July 26, 2020 5:15:52 AM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

 

DO NOT fly without them.

 

-------- Original message --------

From: Jay Scheevel <jay@...>

Date: 7/26/20 8:04 AM (GMT-05:00)

Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

 

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

 

Cheers,

Jay

 

Sent from my Verizon Wireless 4G LTE DROID



"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR




Jay Scheevel
 

As it turns out, the VG’s additional drag is pretty much negligible. There has been debate for many years, but based on my observations and on the assertions of the aerodynamicists that I have talked to, the GU is the faster canard. I am sure that will get some debate out of this group, however. By the way, that is not necessarily the result of the drag of the airfoil alone (GU vs LS1) but of the entire configuration of both wings flying together on the Q2. Some Q1’s have the GU and some have the LS1, so the debate is not just limited to the Q2.

 

Cheers,

Jay

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Dan Thomas via groups.io
Sent: Sunday, July 26, 2020 2:37 PM
To: main@Q-List.groups.io; main@q-list.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

 

Question:  So if the GU airfoil needs VG‘s that cause a little extra drag and the LS-1 needs sparrow strainers that cause a little extra drag, which configuration has the least amount of drag overall?

 

—Dan T.



On Sunday, July 26, 2020, 12:01 PM, Corbin via groups.io <c_geiser@...> wrote:

Thanks Jim.  Oh and if I forgot to update on the VG’s on my GU, I did place them back on and even added a few more on each side.  The new ones are white and blend in a bit better than the metal ones I had on before.

Corbin



On Jul 26, 2020, at 1:43 PM, Jim Patillo <Logistics_engineering@...> wrote:



Corbin,

 

While the GU canard is a decent canard it had the issues all GU’s have. They are useless in rain or bugs without VG’s as I said to you way back. The LS1 canard is much more forgiving and doesn’t change its lift characteristics with rain or bugs on them. Contrary to an opinion stated earlier, the LS1 is not a garbage airfoil or a band aid. One should fly both wings before spewing off about them.

 

The “sparrow strainers” were added because of the increased speed of the 0200 as I understood it, to keep the stick forces lower and to prevent a high speed tuck.

 

Jerry is very correct. Don’t fly the LS1 without the sparrow strainers or you will have a bad day. VG’s are the band aid in my opinion. Just sayin’

 

Jim Patillo

 

N46JP Q200

1750 hours on my LS1 airframe

 

Sent from Outer Space


From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Jerry Marstall <jnmarstall@...>
Sent: Sunday, July 26, 2020 5:15:52 AM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

 

DO NOT fly without them.

 

-------- Original message --------

From: Jay Scheevel <jay@...>

Date: 7/26/20 8:04 AM (GMT-05:00)

Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

 

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

 

Cheers,

Jay

 

Sent from my Verizon Wireless 4G LTE DROID



"Corbin via groups.io" <c_geiser@...> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR




--

Corbin 
N33QR


Jay Scheevel
 

Thanks for that additional info on the Glassair, Bob. That squares with the modeling that I have done removing the “cusp” from the LS1 canard for the Q200. Gives me some confidence in my models. I have a paper on the GA(w)-2 that I will also post in the files section if anyone is interested in the difference between that airfoil and the LS1 (the are very similar).

 

Cheers,

Jay

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Robert Cringely
Sent: Sunday, July 26, 2020 3:05 PM
To: main@q-list.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

 

The GA(W)-2 airfoil used on the original Glasairs had such a cusped trailing edge, one result of which was an unpleasant stiffening of ailerons at high speeds. You see this, too, in a production P-51, though NOT in the EAA's XP-51 prototype, which lacks the cusps and has light ailerons at all speeds. Yes, I know the P-51 didn't have a GA(W)-2 airfoil, but its (different) laminar flow airfoil showed the same characteristics.

 

On the Glasairs, Lyle Powell was the original builder to fill-in the cusps on his Glasair ailerons, lightening them up. Lyle also built the first fixed tricycle Glasair and did the original wingtip extensions. Lyle, who is gone now, was quite the experimenter as well as being the father-in-law of CAFE Foundation founder Brien Seeley.

 

On the Glasair III, II, IIs, etc., Stoddard-Hamilton took the cusp out of the factory molds when Lyle showed them that there really wasn't any performance downside to doing so. Only the original prototype Glasair III, for example, ever had cusps (later filled-in). It also flew 2000+ hours without a carbon fiber horizontal stabilizer.

 

I built Glasair #102 (the first kit) and #123 and eventually de-cusped both. I would suggest doing the same with the LS1 on any Quickie and eliminate the sparrow strainers entirely.

 

Bob Cringely

 

 

On Sun, Jul 26, 2020 at 5:04 AM Jay Scheevel <jay@...> wrote:

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

 

Cheers,

Jay

 

Sent from my Verizon Wireless 4G LTE DROID



"Corbin via groups.io" <c_geiser=icloud.com@groups.io> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR




Corbin
 

Really appreciate all the information everyone sent.  Lots of good reading and reference material.

@Jim - someone mentioned the "RV Lure" nickname and I just hope I can live up to the expectation!

Corbin

On July 26, 2020 at 4:45 PM, Jay Scheevel <jay@...> wrote:

Thanks for that additional info on the Glassair, Bob. That squares with the modeling that I have done removing the “cusp” from the LS1 canard for the Q200. Gives me some confidence in my models. I have a paper on the GA(w)-2 that I will also post in the files section if anyone is interested in the difference between that airfoil and the LS1 (the are very similar).

 

Cheers,

Jay

 

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Robert Cringely
Sent: Sunday, July 26, 2020 3:05 PM
To: main@q-list.groups.io
Subject: Re: [Q-List] Sparrow Strainers - Why and Why Not?

 

The GA(W)-2 airfoil used on the original Glasairs had such a cusped trailing edge, one result of which was an unpleasant stiffening of ailerons at high speeds. You see this, too, in a production P-51, though NOT in the EAA's XP-51 prototype, which lacks the cusps and has light ailerons at all speeds. Yes, I know the P-51 didn't have a GA(W)-2 airfoil, but its (different) laminar flow airfoil showed the same characteristics.

 

On the Glasairs, Lyle Powell was the original builder to fill-in the cusps on his Glasair ailerons, lightening them up. Lyle also built the first fixed tricycle Glasair and did the original wingtip extensions. Lyle, who is gone now, was quite the experimenter as well as being the father-in-law of CAFE Foundation founder Brien Seeley.

 

On the Glasair III, II, IIs, etc., Stoddard-Hamilton took the cusp out of the factory molds when Lyle showed them that there really wasn't any performance downside to doing so. Only the original prototype Glasair III, for example, ever had cusps (later filled-in). It also flew 2000+ hours without a carbon fiber horizontal stabilizer.

 

I built Glasair #102 (the first kit) and #123 and eventually de-cusped both. I would suggest doing the same with the LS1 on any Quickie and eliminate the sparrow strainers entirely.

 

Bob Cringely

 

 

On Sun, Jul 26, 2020 at 5:04 AM Jay Scheevel <jay@...> wrote:

The sparrow strainers on the LS1 are a band-aid. The LS1 airfoil was not designed to have an articulated trailing edge (the elevator). This is because there is a significant under-camber near the trailing edge. The airflow across the trailing edge causes the free floating elevator to move trailing edge up in flight and would require the pilot to compensate with significant aft stick pressure, just to hold the elevator in trail (neutral). The sparrow strainers counter this tendency, so stick pressure is balanced in flight. The shape of the GU canard/elevator does not require this correction, so no sparrow strainers are needed.

 

Cheers,

Jay

 

Sent from my Verizon Wireless 4G LTE DROID



"Corbin via groups.io" <c_geiser=icloud.com@groups.io> wrote:

Help educate me on this old topic.  I understand what they do regarding pitch, however, why do some of us not have them?  Is it a GU vs LS1 thing or is it simply a “don’t have a pitch issue to fix” thing?

Corbin

--
Corbin
N33QR








--

Corbin 
N33QR