Today's Message Index:
----------------------
1. 07:34 AM - Re: Vortex Generators (Galin Hernandez)
2. 10:24 AM - Re: Vortex Generators (Scott Stearns)
3. 10:42 AM - Re: Vortex Generators (JOHN JACKSON)
4. 12:13 PM - Re: Vortex Generators (Kent Pyle)
5. 12:13 PM - Re: Vortex Generators (Kent Pyle)
6. 01:25 PM - Re: Vortex Generators (Larry David)
7. 01:25 PM - Re: Vortex Generators (Galin Hernandez)
8. 02:18 PM - Vortex Generators ()
9. 08:39 PM - Vortex Generators (corrected) ()
Message 1
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| Subject: | Re: Vortex Generators |
Larry;
Think of the elevator as an "upside down" wing. It is pulls the tail down
keeping the nose up. That way if you loose "upside down" lift on the
elevator, the nose drops, proper airflow is re-established and the airplane
flys again.
That's why the VG's are placed on the bottom of the elevator, which is the
"top" of the airfoil.
Galin
N819PR
On Fri, Jan 1, 2010 at 10:31 PM, Larry David <lgdavid@roadrunner.com> wrote:
>
> Thanks OC, I understand the principle but was not comprehending the use on
> the bottom of the tail. Galen's pictures explained the placement. It looks
> like the VGs are about 2/3s of the way back just a bit in front of the
> elevator hinge line. I am still puzzled about how disrupting the boundary
> layer flow across the bottom of the horizontal stab solves the problem.
> Apparently, the VGs are stabilizing the unstable air that is reaching the
> tail. Do you have a better explanation? I guess whatever works is fine.
> Larry
> ----- Original Message ----- From: <bakerocb@cox.net>
> To: <kis-list@matronics.com>; <lgdavid@roadrunner.com>
> Sent: Friday, January 01, 2010 12:03 PM
>
> Subject: Re: KIS-List: Vortex Generators
>
>
>>
>> 1/1/2010
>>
>> Hello Larry, Also see:
>>
>> http://www.avweb.com/news/reviews/182564-1.html
>>
>> for an explanation of how VG's work aerodynamically.
>>
>> 'OC' Says: "The best investment we can make is the effort to gather and
>> understand knowledge."
>>
>> ========================================
>>
>> ----- Original Message ----- From: "Galin Hernandez" <galinhdz@gmail.com>
>> To: <kis-list@matronics.com>
>> Sent: Friday, January 01, 2010 11:47 AM
>> Subject: Re: KIS-List: Vortex Generators
>>
>>
>> Scott;
>>>
>>> My web page is: www.puertoricoflyer.com
>>>
>>> But to get a good understanding of the VG's go to: www.stolspeed.com
>>>
>>> They know more about VG's than I ever will.
>>>
>>> Galin
>>> N819PR
>>>
>>
>> ====================================================
>>
>> On Thu, Dec 31, 2009 at 10:33 PM, Larry David <lgdavid@roadrunner.com
>>> >wrote:
>>>
>>> Galin, What is the URL for your web page? I am trying to understand
>>>> the
>>>> VGs. Larry
>>>>
>>>
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Message 2
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| Subject: | Re: Vortex Generators |
Hi Larry,
-
I think I understand your question...
-
The goal is to get the airflow to follow the contour of the surface, to sta
y 'attached'.- When the boundry layer 'separates'-it causes a lot of tu
rbluence and a huge amount of drag.
-
The large scale vortex caused by the VGs-causes some-drag, but the vort
ex is very good at keeping the airflow following a highly-curved surface
-or a surface with a sudden break as in an elevator at large deflection.
-
Scott
--- On Fri, 1/1/10, Larry David <lgdavid@roadrunner.com> wrote:
From: Larry David <lgdavid@roadrunner.com>
Subject: Re: KIS-List: Vortex Generators
Thanks OC,- I understand the principle but was not comprehending the use
on
the bottom of the tail.- Galen's pictures explained the placement.- It
looks
like the VGs are about 2/3s of the way back just a bit- in front of the
elevator hinge line.- I am still puzzled about how disrupting the boundar
y
layer flow across the bottom of the horizontal stab solves the problem.
Apparently, the VGs are stabilizing the unstable air that is reaching the
tail.- Do you have a better explanation?- I guess whatever works is fin
e.
Larry
----- Original Message -----
From: <bakerocb@cox.net>
Sent: Friday, January 01, 2010 12:03 PM
Subject: Re: KIS-List: Vortex Generators
>
> 1/1/2010
>
> Hello Larry, Also see:
>
> http://www.avweb.com/news/reviews/182564-1.html
>
> for an explanation of how VG's work aerodynamically.
>
> 'OC' Says: "The best investment we can make is the effort to gather and
> understand knowledge."
>
> ========================
================
>
> ----- Original Message -----
> From: "Galin Hernandez" <galinhdz@gmail.com>
> To: <kis-list@matronics.com>
> Sent: Friday, January 01, 2010 11:47 AM
> Subject: Re: KIS-List: Vortex Generators
>
>
>> Scott;
>>
>> My web page is: www.puertoricoflyer.com
>>
>> But to get a good understanding of the VG's go to: www.stolspeed.com
>>
>> They know more about VG's than I ever will.
>>
>> Galin
>> N819PR
>
> ========================
===
>
>> On Thu, Dec 31, 2009 at 10:33 PM, Larry David
>> <lgdavid@roadrunner.com>wrote:
>>
>>>- Galin,- What is the URL for your web page?- I am trying to under
stand
>>> the
>>> VGs.---Larry
>
>
>
le, List Admin.
=0A=0A=0A
Message 3
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| Subject: | Re: Vortex Generators |
=0A=0AGents,=0A=0AWith the VGs fitted has anyone recorded-any reduction i
n-cruising speed or control flutter close to VNE?=0A=0AJohn=0A
Message 4
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| Subject: | Re: Vortex Generators |
Message 5
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| Subject: | Re: Vortex Generators |
No, Kent
----- Original Message -----
From: JOHN JACKSON
To: kis-list@matronics.com
Sent: Saturday, January 02, 2010 12:42 PM
Subject: Re: KIS-List: Vortex Generators
Gents,
With the VGs fitted has anyone recorded any reduction in cruising
speed or control flutter close to VNE?
John
Message 6
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| Subject: | Re: Vortex Generators |
Message 7
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| Subject: | Re: Vortex Generators |
Kent;
I have not experienced any of those, but have not flown near Vne yet.
Galin
N819PR
On Sat, Jan 2, 2010 at 2:13 PM, Kent Pyle <kentpyle@iland.net> wrote:
>
>
Message 8
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| Subject: | Vortex Generators |
1/2/2010
Hello Larry, You wrote:
1) "I understand the principle but was not comprehending the use on the
bottom of the tail."
You have gotten excellent responses to this question from both Galin and
Scott -- I don't think that I could add much in that arena.
2) "Apparently, the VGs are stabilizing the unstable air that is reaching
the tail. Do you have a better explanation?"
Unstable air (commonly called a burble in the aerodynamics lexicon) is
indeed a problem for pitch control at high angles of attack for the KIS
TR-1. But the burble that is creating this problem is being caused by the
pinched in area in the wing to fuselage juncture. When a major air
detachment (burble) is created by this pinched in area and the burble then
flows aft to the horizontal tail surfaces while the pilot is attempting to
hold a very precise nose attitude during the landing flare the resulting
disturbance can be a sudden change in pitch attitude, usually nose down.
Three ways that can be used to help alleviate this particular burble problem
are:
A) Carry or add a little engine power above idle so that a more positive and
continuous airflow is generated in that wing to fuselage junction.
B) Make a larger fillet / fairing in that wing to fuselage junction as
Julian Bone did to help the air flow stay detached better.
C) Put a small strake or vortex generator on the fuselage just forward of
the upper surface of the wing to put some higher energy air into that wing
to fuselage juncture. You can see examples of this technique on the later
models of the Cirrus SR-22 airplane, on some of the RV-8 home built
airplanes, and in a picture on this website labelled "Nacelle strakes bolt
on".
http://www.avweb.com/news/reviews/182564-1.html
3) "I guess whatever works is fine."
I think that everything works a little bit better with understanding.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
==================================================
----- Original Message -----
From: "Galin Hernandez" <galinhdz@gmail.com>
Sent: Saturday, January 02, 2010 10:03 AM
Subject: Re: KIS-List: Vortex Generators
> Larry;
>
> Think of the elevator as an "upside down" wing. It is pulls the tail down
> keeping the nose up. That way if you loose "upside down" lift on the
> elevator, the nose drops, proper airflow is re-established and the
> airplane
> flys again.
>
> That's why the VG's are placed on the bottom of the elevator, which is the
> "top" of the airfoil.
>
> Galin
> N819PR
=======================================================
>
> On Fri, Jan 1, 2010 at 10:31 PM, Larry David <lgdavid@roadrunner.com>
> wrote:
>
>> Thanks OC, I understand the principle but was not comprehending the use
>> on
>> the bottom of the tail. Galen's pictures explained the placement. It
>> looks
>> like the VGs are about 2/3s of the way back just a bit in front of the
>> elevator hinge line. I am still puzzled about how disrupting the
>> boundary
>> layer flow across the bottom of the horizontal stab solves the problem.
>> Apparently, the VGs are stabilizing the unstable air that is reaching the
>> tail. Do you have a better explanation? I guess whatever works is fine.
>> Larry
=======================================================
>> ----- Original Message ----- From: <bakerocb@cox.net>
>> To: <kis-list@matronics.com>; <lgdavid@roadrunner.com>
>> Sent: Friday, January 01, 2010 12:03 PM
>>
>> Subject: Re: KIS-List: Vortex Generators
>>
>>
>>>
>>> 1/1/2010
>>>
>>> Hello Larry, Also see:
>>>
>>> http://www.avweb.com/news/reviews/182564-1.html
>>>
>>> for an explanation of how VG's work aerodynamically.
>>>
>>> 'OC' Says: "The best investment we can make is the effort to gather and
>>> understand knowledge."
>>>
Message 9
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| Subject: | Vortex Generators (corrected) |
----- Original Message -----
From: <bakerocb@cox.net>
<galinhdz@gmail.com>; <sstearns2@yahoo.com>
Sent: Saturday, January 02, 2010 5:17 PM
Subject: KIS-List: Vortex Generators
>
> 1/2/2010
>
> Hello Larry, You wrote:
>
> 1) "I understand the principle but was not comprehending the use on the
> bottom of the tail."
>
> You have gotten excellent responses to this question from both Galin and
> Scott -- I don't think that I could add much in that arena.
>
> 2) "Apparently, the VGs are stabilizing the unstable air that is reaching
> the tail. Do you have a better explanation?"
>
> Unstable air (commonly called a burble in the aerodynamics lexicon) is
> indeed a problem for pitch control at high angles of attack for the KIS
> TR-1. But the burble that is creating this problem is being caused by the
> pinched in area in the wing to fuselage juncture. When a major air
> detachment (burble) is created by this pinched in area and the burble then
> flows aft to the horizontal tail surfaces while the pilot is attempting to
> hold a very precise nose attitude during the landing flare the resulting
> disturbance can be a sudden change in pitch attitude, usually nose down.
>
> Three ways that can be used to help alleviate this particular burble
> problem are:
>
> A) Carry or add a little engine power above idle so that a more positive
> and continuous airflow is generated in that wing to fuselage junction.
>
> B) Make a larger fillet / fairing in that wing to fuselage junction as
> Julian Bone did to help the air flow stay detached better.{Correction:
> Make that read attached better.}
>
> C) Put a small strake or vortex generator on the fuselage just forward of
> the upper surface of the wing to put some higher energy air into that wing
> to fuselage juncture. You can see examples of this technique on the later
> models of the Cirrus SR-22 airplane, on some of the RV-8 home built
> airplanes, and in a picture on this website labelled "Nacelle strakes bolt
> on".
>
> http://www.avweb.com/news/reviews/182564-1.html
>
> 3) "I guess whatever works is fine."
>
> I think that everything works a little bit better with understanding.
>
> 'OC' Says: "The best investment we can make is the effort to gather and
> understand knowledge."
>
> ==================================================
>
> ----- Original Message -----
> From: "Galin Hernandez" <galinhdz@gmail.com>
> To: <kis-list@matronics.com>
> Sent: Saturday, January 02, 2010 10:03 AM
> Subject: Re: KIS-List: Vortex Generators
>
>
>> Larry;
>>
>> Think of the elevator as an "upside down" wing. It is pulls the tail down
>> keeping the nose up. That way if you loose "upside down" lift on the
>> elevator, the nose drops, proper airflow is re-established and the
>> airplane
>> flys again.
>>
>> That's why the VG's are placed on the bottom of the elevator, which is
>> the
>> "top" of the airfoil.
>>
>> Galin
>> N819PR
>
> =======================================================
>>
>> On Fri, Jan 1, 2010 at 10:31 PM, Larry David <lgdavid@roadrunner.com>
>> wrote:
>>
>>> Thanks OC, I understand the principle but was not comprehending the use
>>> on
>>> the bottom of the tail. Galen's pictures explained the placement. It
>>> looks
>>> like the VGs are about 2/3s of the way back just a bit in front of the
>>> elevator hinge line. I am still puzzled about how disrupting the
>>> boundary
>>> layer flow across the bottom of the horizontal stab solves the problem.
>>> Apparently, the VGs are stabilizing the unstable air that is reaching
>>> the
>>> tail. Do you have a better explanation? I guess whatever works is
>>> fine.
>>> Larry
>
> =======================================================
>
>>> ----- Original Message ----- From: <bakerocb@cox.net>
>>> To: <kis-list@matronics.com>; <lgdavid@roadrunner.com>
>>> Sent: Friday, January 01, 2010 12:03 PM
>>>
>>> Subject: Re: KIS-List: Vortex Generators
>>>
>>>
>>>>
>>>> 1/1/2010
>>>>
>>>> Hello Larry, Also see:
>>>>
>>>> http://www.avweb.com/news/reviews/182564-1.html
>>>>
>>>> for an explanation of how VG's work aerodynamically.
>>>>
>>>> 'OC' Says: "The best investment we can make is the effort to gather and
>>>> understand knowledge."
>>>>
>
>
>
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