---------------------------------------------------------- TeamGrumman-List Digest Archive --- Total Messages Posted Thu 09/09/10: 7 ---------------------------------------------------------- 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 _____________________________________ Time: 11:12:21 AM PST US From: Gary Vogt Subject: TeamGrumman-List: air flow 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 _____________________________________ Time: 11:45:37 AM PST US From: Gary Vogt 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 3 _____________________________________ Time: 02:13:18 PM PST US From: "flyv35b" 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 4 _____________________________________ Time: 06:06:34 PM PST US From: Bruce Smith 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. > > > ________________________________ Message 5 _____________________________________ Time: 06:36:15 PM PST US From: Gary Vogt Subject: Re: TeamGrumman-List: Power Flow. This fills the old hole. Or maybe you could get a bigger screen ________________________________ From: flyv35b 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 _____________________________________ Time: 06:58:57 PM PST US From: Gary Vogt Subject: Re: TeamGrumman-List: air flow 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 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. > > > ________________________________ Message 7 _____________________________________ Time: 07:02:41 PM PST US From: Brock Windsor Subject: Re: TeamGrumman-List: Power Flow. This fills the old hole. Or get stronger glasses ;) --- On Thu, 9/9/10, Gary Vogt wrote: From: Gary Vogt Subject: Re: TeamGrumman-List: Power Flow. This fills the old hole. Or maybe you could get a bigger screen From: flyv35b 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 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message teamgrumman-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/TeamGrumman-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/teamgrumman-list Browse Digests http://www.matronics.com/digest/teamgrumman-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.