Re: Sparrow strainer stall

Jay Scheevel

Oops, put the strainer on above instead of below he airfoil. Looks like the same story though…you decide.

Cheers,

Jay

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Jay Scheevel
Sent: Thursday, March 19, 2020 9:39 AM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall

Hi Bruce,

If the airflow were to not detach from the elevator (in a perfect world), the airflow would follow the black streamlines shown in the computation below. These “ideal” streamlines suggest that the sparrow strainer would actually see a low angle of incidence, even when the canard is at a high attack angle (10 degrees) and the elevator is deflected 10 degrees down. Since my computation method is incapable of modeling the separation bubble and turbulent counterflow around the trailing edge of the elevator, the streamlines in that region of my model are not representative of real life. In the real world, I suspect what you are seeing from your sparrow strainer tufts is not related to the sparrow strainer stalling per se, but instead the sparrow strainer just happens to be caught up in the larger flow field of air flowing up and around the trailing edge of the elevator within the larger separation bubble. In other words, there is reverse airflow over the sparrow strainer because the elevator is stalled, not because the sparrow strainer is stalled. Not much you can do to get the sparrow strainer to fly when the airflow over it is backwards. My 2 cents.

Cheers,

Jay

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Bruce Crain
Sent: Wednesday, March 18, 2020 9:18 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall

On the bottom as the stall was happening on the underneath side of the strainer.  The tufts on the aft of the strainers were disappearing underneath the strainers.

Bruce

---------- Original Message ----------
From: "Jay Scheevel" <jay@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Wed, 18 Mar 2020 19:44:54 -0600

Bruce,

which side of the strainer did you put the zigzag tape on? Top or bottom?

Jay

Sent from my Verizon Wireless 4G LTE DROID

Bruce Crain <jcrain2@...> wrote:

Jon,

I tried the zig zag tape and did get the stall to go away right up the last test where I finally had all of the zig zag cleaned off.  With the zig zag the stall would not happen on the strainer but it created drag and dragged the strainer up and thus the elevator also.  The elevator would ride up a half inch or so and stay and I would reflex the ailerons up to compensate.

I am going to test actual vortex generators next.  Trying to make them small enough so that they don't  create drag and pull the elevator up.  So the zig zag did work but with less than great results for the trim I am used to seeing.

Before the next tests I am pulling a cylinder to check for a leak around a cylinder base stud or cylinder base o ring perhaps.

Bruce Crain

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Wed, 18 Mar 2020 11:41:07 -0700

Howdy Jay,

I recently heard a woman admit that there are "degrees of yes" - I was stunned. Of course, I was very familiar with this phenomena but had never heard the other gender actually admit to it. Now you are talking about "degrees of stalled" - please confirm your gender!!

:-)

Seriously, I know you are correct. I also saw this in my GU canard tuft testing (moving up/forward on the airfoil).

Bruce; I don't know what to say on your strainers. I struggled to know how to set them (and eventually gave up on them on my GU, since they weren't needed/per-plans (instead, springs take up the load, as I recall)).  I imagine you have already tried reducing their angle of attack - and noted some change in stick force??

Jon

Re: Sparrow strainer stall

Jay Scheevel

Hi Bruce,

If the airflow were to not detach from the elevator (in a perfect world), the airflow would follow the black streamlines shown in the computation below. These “ideal” streamlines suggest that the sparrow strainer would actually see a low angle of incidence, even when the canard is at a high attack angle (10 degrees) and the elevator is deflected 10 degrees down. Since my computation method is incapable of modeling the separation bubble and turbulent counterflow around the trailing edge of the elevator, the streamlines in that region of my model are not representative of real life. In the real world, I suspect what you are seeing from your sparrow strainer tufts is not related to the sparrow strainer stalling per se, but instead the sparrow strainer just happens to be caught up in the larger flow field of air flowing up and around the trailing edge of the elevator within the larger separation bubble. In other words, there is reverse airflow over the sparrow strainer because the elevator is stalled, not because the sparrow strainer is stalled. Not much you can do to get the sparrow strainer to fly when the airflow over it is backwards. My 2 cents.

Cheers,

Jay

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Bruce Crain
Sent: Wednesday, March 18, 2020 9:18 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall

On the bottom as the stall was happening on the underneath side of the strainer.  The tufts on the aft of the strainers were disappearing underneath the strainers.

Bruce

---------- Original Message ----------
From: "Jay Scheevel" <jay@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Wed, 18 Mar 2020 19:44:54 -0600

Bruce,

which side of the strainer did you put the zigzag tape on? Top or bottom?

Jay

Sent from my Verizon Wireless 4G LTE DROID

Bruce Crain <jcrain2@...> wrote:

Jon,

I tried the zig zag tape and did get the stall to go away right up the last test where I finally had all of the zig zag cleaned off.  With the zig zag the stall would not happen on the strainer but it created drag and dragged the strainer up and thus the elevator also.  The elevator would ride up a half inch or so and stay and I would reflex the ailerons up to compensate.

I am going to test actual vortex generators next.  Trying to make them small enough so that they don't  create drag and pull the elevator up.  So the zig zag did work but with less than great results for the trim I am used to seeing.

Before the next tests I am pulling a cylinder to check for a leak around a cylinder base stud or cylinder base o ring perhaps.

Bruce Crain

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Wed, 18 Mar 2020 11:41:07 -0700

Howdy Jay,

I recently heard a woman admit that there are "degrees of yes" - I was stunned. Of course, I was very familiar with this phenomena but had never heard the other gender actually admit to it. Now you are talking about "degrees of stalled" - please confirm your gender!!

:-)

Seriously, I know you are correct. I also saw this in my GU canard tuft testing (moving up/forward on the airfoil).

Bruce; I don't know what to say on your strainers. I struggled to know how to set them (and eventually gave up on them on my GU, since they weren't needed/per-plans (instead, springs take up the load, as I recall)).  I imagine you have already tried reducing their angle of attack - and noted some change in stick force??

Jon

Re: Sparrow strainer stall

Bruce Crain

I haven't changed the angle of attach on the strainers yet.  They are set for level cruise and I don't want that to go away so Vortex Generators next.  I  hope that the generators will make a bit of extra lift downward to override the push back and upwards they may produce.  I am moving pretty slow on all of this as I am working on the RV as well.
Bruce

Bruce; I don't know what to say on your strainers. I struggled to know how to set them (and eventually gave up on them on my GU, since they weren't needed/per-plans (instead, springs take up the load, as I recall)).  I imagine you have already tried reducing their angle of attack - and noted some change in stick force??

Jon

Re: Sparrow strainer stall

Bruce Crain

On the bottom as the stall was happening on the underneath side of the strainer.  The tufts on the aft of the strainers were disappearing underneath the strainers.
Bruce

---------- Original Message ----------
From: "Jay Scheevel" <jay@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Wed, 18 Mar 2020 19:44:54 -0600

Bruce,
which side of the strainer did you put the zigzag tape on? Top or bottom?
Jay

Sent from my Verizon Wireless 4G LTE DROID

Bruce Crain <jcrain2@...> wrote:

Jon,
I tried the zig zag tape and did get the stall to go away right up the last test where I finally had all of the zig zag cleaned off.  With the zig zag the stall would not happen on the strainer but it created drag and dragged the strainer up and thus the elevator also.  The elevator would ride up a half inch or so and stay and I would reflex the ailerons up to compensate.

I am going to test actual vortex generators next.  Trying to make them small enough so that they don't  create drag and pull the elevator up.  So the zig zag did work but with less than great results for the trim I am used to seeing.

Before the next tests I am pulling a cylinder to check for a leak around a cylinder base stud or cylinder base o ring perhaps.

Bruce Crain

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Wed, 18 Mar 2020 11:41:07 -0700

Howdy Jay,

I recently heard a woman admit that there are "degrees of yes" - I was stunned. Of course, I was very familiar with this phenomena but had never heard the other gender actually admit to it. Now you are talking about "degrees of stalled" - please confirm your gender!!

:-)

Seriously, I know you are correct. I also saw this in my GU canard tuft testing (moving up/forward on the airfoil).

Bruce; I don't know what to say on your strainers. I struggled to know how to set them (and eventually gave up on them on my GU, since they weren't needed/per-plans (instead, springs take up the load, as I recall)).  I imagine you have already tried reducing their angle of attack - and noted some change in stick force??

Jon

Re: Sparrow strainer stall

Jay Scheevel

Bruce,
which side of the strainer did you put the zigzag tape on? Top or bottom?
Jay

Sent from my Verizon Wireless 4G LTE DROID

Bruce Crain <jcrain2@...> wrote:

Jon,
I tried the zig zag tape and did get the stall to go away right up the last test where I finally had all of the zig zag cleaned off.  With the zig zag the stall would not happen on the strainer but it created drag and dragged the strainer up and thus the elevator also.  The elevator would ride up a half inch or so and stay and I would reflex the ailerons up to compensate.

I am going to test actual vortex generators next.  Trying to make them small enough so that they don't  create drag and pull the elevator up.  So the zig zag did work but with less than great results for the trim I am used to seeing.

Before the next tests I am pulling a cylinder to check for a leak around a cylinder base stud or cylinder base o ring perhaps.

Bruce Crain

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Wed, 18 Mar 2020 11:41:07 -0700

Howdy Jay,

I recently heard a woman admit that there are "degrees of yes" - I was stunned. Of course, I was very familiar with this phenomena but had never heard the other gender actually admit to it. Now you are talking about "degrees of stalled" - please confirm your gender!!

:-)

Seriously, I know you are correct. I also saw this in my GU canard tuft testing (moving up/forward on the airfoil).

Bruce; I don't know what to say on your strainers. I struggled to know how to set them (and eventually gave up on them on my GU, since they weren't needed/per-plans (instead, springs take up the load, as I recall)).  I imagine you have already tried reducing their angle of attack - and noted some change in stick force??

Jon

Re: Couple new videos (non-Q)

Rick Hole

Rocks!  Wow, thanks for the ride!

Rick Hole

Re: Sparrow strainer stall

Bruce Crain

Jon,
I tried the zig zag tape and did get the stall to go away right up the last test where I finally had all of the zig zag cleaned off.  With the zig zag the stall would not happen on the strainer but it created drag and dragged the strainer up and thus the elevator also.  The elevator would ride up a half inch or so and stay and I would reflex the ailerons up to compensate.

I am going to test actual vortex generators next.  Trying to make them small enough so that they don't  create drag and pull the elevator up.  So the zig zag did work but with less than great results for the trim I am used to seeing.

Before the next tests I am pulling a cylinder to check for a leak around a cylinder base stud or cylinder base o ring perhaps.

Bruce Crain

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Wed, 18 Mar 2020 11:41:07 -0700

Howdy Jay,

I recently heard a woman admit that there are "degrees of yes" - I was stunned. Of course, I was very familiar with this phenomena but had never heard the other gender actually admit to it. Now you are talking about "degrees of stalled" - please confirm your gender!!

:-)

Seriously, I know you are correct. I also saw this in my GU canard tuft testing (moving up/forward on the airfoil).

Bruce; I don't know what to say on your strainers. I struggled to know how to set them (and eventually gave up on them on my GU, since they weren't needed/per-plans (instead, springs take up the load, as I recall)).  I imagine you have already tried reducing their angle of attack - and noted some change in stick force??

Jon

Re: Couple new videos (non-Q)

Jon Finley

Thanks all!  Flying is GRAND!!!

I'm with you Jay - I should have been a geologist cause I can't seem to get enough of 'em!

Jon

Re: Sparrow strainer stall

Jay Scheevel

Hi Jon,

I recently heard someone refer to “gender fluid”. I have been checking at the local auto parts store, but have not been able to find any of that.  😉

Cheers,

Jay

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Jon Finley
Sent: Wednesday, March 18, 2020 12:41 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall

Howdy Jay,

I recently heard a woman admit that there are "degrees of yes" - I was stunned. Of course, I was very familiar with this phenomena but had never heard the other gender actually admit to it. Now you are talking about "degrees of stalled" - please confirm your gender!!

:-)

Seriously, I know you are correct. I also saw this in my GU canard tuft testing (moving up/forward on the airfoil).

Bruce; I don't know what to say on your strainers. I struggled to know how to set them (and eventually gave up on them on my GU, since they weren't needed/per-plans (instead, springs take up the load, as I recall)).  I imagine you have already tried reducing their angle of attack - and noted some change in stick force??

Jon

Re: Sparrow strainer stall

Jon Finley

Howdy Jay,

I recently heard a woman admit that there are "degrees of yes" - I was stunned. Of course, I was very familiar with this phenomena but had never heard the other gender actually admit to it. Now you are talking about "degrees of stalled" - please confirm your gender!!

:-)

Seriously, I know you are correct. I also saw this in my GU canard tuft testing (moving up/forward on the airfoil).

Bruce; I don't know what to say on your strainers. I struggled to know how to set them (and eventually gave up on them on my GU, since they weren't needed/per-plans (instead, springs take up the load, as I recall)).  I imagine you have already tried reducing their angle of attack - and noted some change in stick force??

Jon

Re: Sparrow strainer stall

Jay Scheevel

Hi Bruce,

A few years ago, Reg Clarke sent me some video of his tufted canard in flight. He was trying to resolve some elevator vibration he had over certain airspeed ranges and he did videos to figure that out. Here (https://q-list.groups.io/g/main/files/Reg_Clarke_tufted_canard_snapshots.pdf) is a sequence of snaps that I put together from his video at different airspeeds from cruise to pattern to touchdown.

I have posted a dashed red line that represents my interpreted forward limit of the separation bubble on  the canard. The tuft behavior on the sparrow strainer will look familiar to you, but you can also see that the separation climbs up the elevator and canard so there is no clean stall break, it stalls gradually, which is a characteristic of a laminar flow airfoil.

John Roncz created a canard for the Long-EZ to replace the GU canard which incorporated a slot core that had no bottom on the slot, so when the elevator was deflected down, some of the airflow went up through the slot and over the top of the elevator to help keep the flow connected to the elevator’s upper surface. I am not sure how effective this was, since I am not an EZ guy.

Cheers,

Jay

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Bruce Crain
Sent: Wednesday, March 18, 2020 9:02 AM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall

Hi Jon!

No the canard isn't stalled but it looks like the elevator is stalled.  The tufts are gyrating in circular motion on the elevator right in front of the sparrow strainer and also in the outboard end of the elevator.  It would be interesting to see if every Quickie had the same scenario with respect to the elevator.  I had suspicion-ed that in the past when I flew through the rain.  The dust mixed with the rain and made trails from out board to inboard.

We could be loosing lift in this area but how to correct it?  The elevator slot core is pretty tight so I am not sure a seal is possible.  Also, perhaps an air dam on the outboard end of the elevator could be possible.  If lift is re-attached to the top of the elevator would the sparrow strainer need to be augmented to keep it level in flight?  There would be a lot more up lift in the elevator if re attachment were possible.

Could we be loosing airspeed!!!  OMGosh!  Somebody fix it!!  Any aerodynamicists in the room?!!

Bruce Crain

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Tue, 17 Mar 2020 13:00:41 -0700

Sorry Bruce... I just saw this.

It's hard to see from the photo - are the tufts on the canard also stalled??

Jon

Re: Couple new videos (non-Q)

Bruce Crain

Awesome "possum!  You are an animal Jon!
Bruce

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: [Q-List] Couple new videos (non-Q)
Date: Tue, 17 Mar 2020 12:49:11 -0700

Couple new videos for ya'll.

My poor production skills remain but the flying is so very much fun!!!

https://youtu.be/Bcho2YTkNnk

Jon

Re: Sparrow strainer stall

Bruce Crain

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Tue, 17 Mar 2020 13:19:30 -0700

Come to think of it, didn't the Wadelow canard work by making the airflow backwards on the bottom of the airfoil and then wrap around the nose to flow over the top surface a second time?? :-)

Re: Sparrow strainer stall

Bruce Crain

Hi Jon!
No the canard isn't stalled but it looks like the elevator is stalled.  The tufts are gyrating in circular motion on the elevator right in front of the sparrow strainer and also in the outboard end of the elevator.  It would be interesting to see if every Quickie had the same scenario with respect to the elevator.  I had suspicion-ed that in the past when I flew through the rain.  The dust mixed with the rain and made trails from out board to inboard.

We could be loosing lift in this area but how to correct it?  The elevator slot core is pretty tight so I am not sure a seal is possible.  Also, perhaps an air dam on the outboard end of the elevator could be possible.  If lift is re-attached to the top of the elevator would the sparrow strainer need to be augmented to keep it level in flight?  There would be a lot more up lift in the elevator if re attachment were possible.

Could we be loosing airspeed!!!  OMGosh!  Somebody fix it!!  Any aerodynamicists in the room?!!

Bruce Crain

---------- Original Message ----------
From: "Jon Finley" <jd@...>
To: main@Q-List.groups.io
Subject: Re: [Q-List] Sparrow strainer stall
Date: Tue, 17 Mar 2020 13:00:41 -0700

Sorry Bruce... I just saw this.

It's hard to see from the photo - are the tufts on the canard also stalled??

Jon

Re: Couple new videos (non-Q)

Jay Scheevel

Very nice videos, Jon. As a geologist, I really appreciate the CLOSE looks at the rocks! :-)

Cheers,
Jay

On Tue, 17 Mar 2020 12:49:11 -0700, "Jon Finley" <jd@...> wrote:

Couple new videos for ya'll.

My poor production skills remain but the flying is so very much fun!!!

https://youtu.be/Bcho2YTkNnk

Jon

Re: Couple new videos (non-Q)

Gotta chime in on this one. Watched em both.
Very relaxing. Nice break from a busy day.
K Welsh
Quickie N494K 413 hrs

On Tue, Mar 17, 2020 at 9:40 PM Kevin Boddicker <trumanst@...> wrote:

Jon,
very nice. As Bruce Crain would say, “cragly”!!!

Stay well my friend.

Kevin Boddicker
TriQ 200 N7868B 503 hrs
Luana, IA.

On Mar 17, 2020, at 2:49 PM, Jon Finley <jd@...> wrote:

Couple new videos for ya'll.

My poor production skills remain but the flying is so very much fun!!!

https://youtu.be/Bcho2YTkNnk

https://youtu.be/-abd2JIlxeY

Jon

Re: Couple new videos (non-Q)

Kevin Boddicker

Jon,
very nice. As Bruce Crain would say, “cragly”!!!

Stay well my friend.

Kevin Boddicker
TriQ 200 N7868B    503
hrs
Luana, IA.

On Mar 17, 2020, at 2:49 PM, Jon Finley <jd@...> wrote:

Couple new videos for ya'll.

My poor production skills remain but the flying is so very much fun!!!

Jon

Re: Elevator pitch trim installed and tested

Jay Scheevel

Hi Richard,

I flew for 15 months without this and had no problems. I just decided to put one in after I started loading my plane more aft and wanted to see over the nose when landing (and not bounce the tail on the runway). My rear wing has 1.5 degrees nose down relative to plans, so it already tends to fly tail low when slow. You should not need additional trim if you have the reflexor installed. I had no problem getting mine trimmed for landing with just the reflexor. My trim routine is more complicated now, but I don’t think you want to complicate things on your first flights.

Cheers,

Jay

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Richard Thomson
Sent: Tuesday, March 17, 2020 3:01 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Elevator pitch trim installed and tested

I thought you suggested I didnt need an elevator trim ? :-0

On 17/03/2020 17:21, Jay Scheevel wrote:

Thanks David!  I almost knew that I would hear from you first. 😊  I take your quick response to be a compliment…of sorts. I was limited with respect to space, so the compler-kation factor went up to accommodate. Thanks for your comments.

Cheers,

Jay

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of David J. Gall
Sent: Tuesday, March 17, 2020 11:04 AM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Elevator pitch trim installed and tested

Jay,

I’m laughing out loud as I’m writing this: Did you previously design suspension systems for the BMW motorcar company? That’s the most compler-kated way I could imagine to do that — and yet, it precisely meets requirements. Amazing! 😉

Keep your spring forces as light as possible — it sounds like you’re already there — and keep your spring rates as low as possible by using the longest springs that’ll fit — again, it looks like you’re already there. So, bravo on getting the important variables dialed in, but your overkill factor is ... large. 🤷😂

Keep up the good work!

Re: Elevator pitch trim installed and tested

Richard Thomson

I thought you suggested I didnt need an elevator trim ? :-0

On 17/03/2020 17:21, Jay Scheevel wrote:

Thanks David!  I almost knew that I would hear from you first. 😊  I take your quick response to be a compliment…of sorts. I was limited with respect to space, so the compler-kation factor went up to accommodate. Thanks for your comments.

Cheers,

Jay

From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of David J. Gall
Sent: Tuesday, March 17, 2020 11:04 AM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Elevator pitch trim installed and tested

Jay,

I’m laughing out loud as I’m writing this: Did you previously design suspension systems for the BMW motorcar company? That’s the most compler-kated way I could imagine to do that — and yet, it precisely meets requirements. Amazing! 😉

Keep your spring forces as light as possible — it sounds like you’re already there — and keep your spring rates as low as possible by using the longest springs that’ll fit — again, it looks like you’re already there. So, bravo on getting the important variables dialed in, but your overkill factor is ... large. 🤷😂

Keep up the good work!

Re: Sparrow strainer stall

Jon Finley

Come to think of it, didn't the Wadelow canard work by making the air flow backwards on the bottom of the airfoil and then wrap around the nose to flow over the top surface a second time?? :-)

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