Today's Message Index:
----------------------
1. 11:12 AM - air flow (Gary Vogt)
2. 11:45 AM - Power Flow. This fills the old hole. (Gary Vogt)
3. 02:13 PM - Re: Power Flow. This fills the old hole. (flyv35b)
4. 06:06 PM - Re: air flow (Bruce Smith)
5. 06:36 PM - Re: Power Flow. This fills the old hole. (Gary Vogt)
6. 06:58 PM - Re: air flow (Gary Vogt)
7. 07:02 PM - Re: Power Flow. This fills the old hole. (Brock Windsor)
Message 1
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This is just a sample of the hundreds of tests I've done trying to get rid of
airframe drag.
The first pic, 612, is the bottom of the plane without the fairing. Notice the
cross flow. There is a significant amount of drag in this photo. Here's
something I'll bet you didn't know: that cross flow makes noise. If you can
make the right frequency, you can enhance the flow attachment. That's extremely
rare.
The next pic, 400, is using the first style fairing. There is still a small
recirculation zone adjacent to the fairing behind the PFS pipe. If you can see
the little black dots in the 612 pic, those are rivnuts. I moved the fairing
around a bit to see if I could affect the strength of the recirculation zone.
The major cross flow you see coming across from the sides is due to air flow
during climb out. I've toyed with the idea if drilling a series of small holes
in the cowling and bleeding oil from the inside after I level off.
The second style fairing was an attempt to keep the airflow attached to the
bottom of the muffler as it exits the pipe. The fairing gets sooty but it does
help some.
The third style fairing, the short one, was an attempt to affect the
recirculation zone.
The recirculation zone, as it happens, was due to the nose strut faring I had on
the original cowling. After I got rid of the fairing, CHTs went up about 15
degrees, but the plane was 2-4 knots faster.
I have another 'mod' in the works as I write this. Trying to keep the speed and
improve the cooling. It's a very fine tightrope.
Gary
Message 2
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| Subject: | Power Flow. This fills the old hole. |
I see a lot of scabbed on pieces of aluminum to fill in the hole where the old
tail pipe came out. Very amateur. These are fiberglass hole covers that are
contoured to the shape of the cowling.
Message 3
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| Subject: | Re: Power Flow. This fills the old hole. |
Gary,
Nice photos of your testing, etc. But it would be help if you could
reduce the size of photos for emailing so one could look at them without
having to scroll back and forth. Or maybe just take the photo at a
smaller resolution size.
Cliff
----- Original Message -----
From: Gary Vogt
To: Teamgrumman List
Sent: Thursday, September 09, 2010 11:19 AM
Subject: TeamGrumman-List: Power Flow. This fills the old hole.
I see a lot of scabbed on pieces of aluminum to fill in the hole where
the old tail pipe came out. Very amateur. These are fiberglass hole
covers that are contoured to the shape of the cowling.
Message 4
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Gary,
So, if I understand this, at the correct frequency of sound, you can achieve a
drag reduction?
Bruce Smith
On Sep 9, 2010, at 2:09 PM, Gary Vogt wrote:
> This is just a sample of the hundreds of tests I've done trying to get rid of
airframe drag.
>
> The first pic, 612, is the bottom of the plane without the fairing. Notice the
cross flow. There is a significant amount of drag in this photo. Here's something
I'll bet you didn't know: that cross flow makes noise. If you can make
the right frequency, you can enhance the flow attachment. That's extremely
rare.
>
>
> <IMG_0612.JPG><PICT0400.JPG>
Message 5
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| Subject: | Re: Power Flow. This fills the old hole. |
Or maybe you could get a bigger screen
________________________________
From: flyv35b <flyv35b@minetfiber.com>
Sent: Thu, September 9, 2010 1:59:22 PM
Subject: Re: TeamGrumman-List: Power Flow. This fills the old hole.
Gary,
Nice photos of your testing, etc. But it would be help if you could reduce the
size of photos for emailing so one could look at them without having to scroll
back and forth. Or maybe just take the photo at a smaller resolution size.
Cliff
----- Original Message -----
>From: Gary Vogt
>To: Teamgrumman List
>Sent: Thursday, September 09, 2010 11:19 AM
>Subject: TeamGrumman-List: Power Flow. This fills the old hole.
>
>
>I see a lot of scabbed on pieces of aluminum to fill in the hole where the
>old tail pipe came out. Very amateur. These are fiberglass hole covers that
>are contoured to the shape of the cowling.
>
>
Message 6
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Yes. In the 70's and 80's there was a significant amount of research using
sound generation (speakers) that blasted sound onto the wing. What it did was
energize the boundary layer (up to .1 inches above the surface of the wing).
The airflow would reattach. This was based on research done in the early
1900's by Prandtl, Helmholts, and Blasius.
________________________________
From: Bruce Smith <haveblue1@mac.com>
Sent: Thu, September 9, 2010 6:03:35 PM
Subject: Re: TeamGrumman-List: air flow
Gary,
So, if I understand this, at the correct frequency of sound, you can achieve a
drag reduction?
Bruce Smith
On Sep 9, 2010, at 2:09 PM, Gary Vogt wrote:
This is just a sample of the hundreds of tests I've done trying to get rid of
airframe drag.
>
>
>The first pic, 612, is the bottom of the plane without the fairing. Notice the
>cross flow. There is a significant amount of drag in this photo. Here's
>something I'll bet you didn't know: that cross flow makes noise. If you can
>make the right frequency, you can enhance the flow attachment. That's extremely
>rare.
>
>
><IMG_0612.JPG><PICT0400.JPG>
Message 7
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| Subject: | Re: Power Flow. This fills the old hole. |
Or get stronger glasses ;)
--- On Thu, 9/9/10, Gary Vogt <teamgrumman@YAHOO.COM> wrote:
From: Gary Vogt <teamgrumman@YAHOO.COM>
Subject: Re: TeamGrumman-List: Power Flow. This fills the old hole.
Or maybe you could get a bigger screen
From: flyv35b <flyv35b@minetfiber.com>
Sent: Thu, September 9, 2010 1:59:22 PM
Subject: Re: TeamGrumman-List: Power Flow. This fills the old hole.
#yiv1432465371 DIV {
MARGIN:0px;}
Gary,
-
Nice photos of your testing, etc.- But it would be help if you could redu
ce the size of photos for emailing so one could look at them without having
to scroll back and forth.- Or maybe just take the photo at a smaller res
olution size.
-
Cliff
----- Original Message -----
From: Gary Vogt
Sent: Thursday, September 09, 2010 11:19 AM
Subject: TeamGrumman-List: Power Flow. This fills the old hole.
I see a lot of scabbed on pieces of aluminum to fill in the hole where the
old tail pipe came out. -Very amateur. -These are fiberglass hole cover
s that are contoured to the shape of the cowling.
=0A=0A=0A
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