---------------------------------------------------------- Lightning-List Digest Archive --- Total Messages Posted Fri 02/22/08: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:03 AM - Re: Lightning bottom cowl air dam photos (Daniel DW) 2. 01:10 AM - Re: Lightning bottom cowl air dam photos (Daniel DW) 3. 01:14 AM - Re: Lightning bottom cowl air dam photos (Daniel DW) 4. 06:53 AM - Re: Lightning bottom cowl air dam photos (flylightning) 5. 11:49 AM - Re: Lightning bottom cowl air dam photos-Esqual outlet (James, Clive R) 6. 11:35 PM - Re: Lightning bottom cowl air dam photos (Brian Whittingham) ________________________________ Message 1 _____________________________________ Time: 01:03:58 AM PST US From: Daniel DW Subject: RE: Lightning-List: Lightning bottom cowl air dam photos Clive, we could add a lip on our cowling, made in alu. Danny > Subject: FW: Lightning-List: Lightning bottom cowl air dam photos> Date: Fri, 22 Feb 2008 06:55:55 +0000> From: clive.james@uk.bp.com> To: lightning -list@matronics.com> > Apologies I should have carried on reading the next few posts. Though my> comments still apply. > > Looking at the pictures of the Lightning ducts and my Esquals the size> difference is massive.> > Wort h some 'liquid engineering' if there's space.> > Regards, Clive> > -----Ori ginal Message-----> From: owner-lightning-list-server@matronics.com> [mailt o:owner-lightning-list-server@matronics.com] On Behalf Of> N1BZRich@aol.com > Sent: 21 February 2008 22:07> To: lightning-list@matronics.com> Subject: Lightning-List: Lightning bottom cowl air dam photos> > Danny,> Right after I sent the previous message I remembered where you could> see the lip on t he Lightning's bottom cowl. Go to the Lightning news> web page http://www.a rionaircraft.com/News.html, and scroll down to near> the bottom and look at the photos for 1/5/2006, Lightning Cowl> Finalized, and also 2/15/2005, Wh eel and gear fairings set for trial.> Both of these set of photos show the lip or air dam. The idea is the> same as on a car. The air dam forces air d own and thus creates a lower> pressure area under the bottom cowl. Hope thi s helps.> Buz> > > > ________________________________> > Delicious ideas to please the pickiest eaters. Watch the video on AOL> Living.> s-duffy/205082 7?NCID=aolcmp00300000002598> _________________________________________________________________ Start een boeiend online leven...helemaal gratis! http://get.live.com ________________________________ Message 2 _____________________________________ Time: 01:10:18 AM PST US From: Daniel DW Subject: RE: Lightning-List: Lightning bottom cowl air dam photos Thanks Buz, I understand the rational behind it. I will do some testing as soon as my Esqual has been repaired. During the 1 flight I did in my plane, temperatures were quite high but wit hin limits. Danny From: N1BZRich@aol.comDate: Thu, 21 Feb 2008 17:06:53 -0500Subject: Lightni ng-List: Lightning bottom cowl air dam photosTo: lightning-list@matronics.c om Danny, Right after I sent the previous message I remembered where you could se e the lip on the Lightning's bottom cowl. Go to the Lightning news web pag e http://www.arionaircraft.com/News.html, and scroll down to near the botto m and look at the photos for 1/5/2006, Lightning Cowl Finalized, and also 2 /15/2005, Wheel and gear fairings set for trial. Both of these set of phot os show the lip or air dam. The idea is the same as on a car. The air dam forces air down and thus creates a lower pressure area under the bottom co wl. Hope this helps. Buz Delicious ideas to please the pickiest eaters. Watch the video on AOL Livin g. _________________________________________________________________ Neem je vrienden overal mee dankzij Messenger op je gsm. http://www.windowslivemobile.msn.com/nl-be ________________________________ Message 3 _____________________________________ Time: 01:14:07 AM PST US From: Daniel DW Subject: RE: Lightning-List: Lightning bottom cowl air dam photos Linda, these pictures show clearly the differences with the Esqual cowling. It makes sense to modify the Esqual cowling.Regards Danny : Lightning-List: Lightning bottom cowl air dam photosTo: lightning-list@ma tronics.com Danny, These pictures might give you the idea; I cut the lip off to clear the exhaust because it was touching and burning the cowl. However, that raise d temps a lot so I had to put a lip back on but moved it about 3/4 inch far ther forward. I think you can see the shape of it though and get the idea. Linda ----- Original Message ----- From: N1BZRich@aol.com Sent: Thursday, February 21, 2008 5:06 PM Subject: Lightning-List: Lightning bottom cowl air dam photos Danny, Right after I sent the previous message I remembered where you could se e the lip on the Lightning's bottom cowl. Go to the Lightning news web pag e http://www.arionaircraft.com/News.html, and scroll down to near the botto m and look at the photos for 1/5/2006, Lightning Cowl Finalized, and also 2 /15/2005, Wheel and gear fairings set for trial. Both of these set of phot os show the lip or air dam. The idea is the same as on a car. The air dam forces air down and thus creates a lower pressure area under the bottom co wl. Hope this helps. Buz Delicious ideas to please the pickiest eaters. Watch the video on AOL Livin g. href="http://www.matronics.com/Navigator?Lightning-List">http://www.matro nics.com/Navigator?Lightning-List href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c _________________________________________________________________ Neem je vrienden overal mee dankzij Messenger op je gsm. http://www.windowslivemobile.msn.com/nl-be ________________________________ Message 4 _____________________________________ Time: 06:53:38 AM PST US From: "flylightning" Subject: RE: Lightning-List: Lightning bottom cowl air dam photos I discussed this at one time with doug from jabiru when he was over here in TN ..about 2.5 times the exit area to inlet area is a good start..this is for a cowl with a lip or fixed down cowl flap if you will...kent pacer refers to an exit area of 80% of the inlet area which would work well with cruise but not high power low speed in climb.so if you could get 250% exit for take off and close the exit down to 80% for cruise with a movable cowl flap you should have good cooling and reduced drag in cruise...Hmmm..something for the skunk works on the new demo? Nick _____ From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of Brian Whittingham Sent: Friday, February 22, 2008 1:50 AM Subject: RE: Lightning-List: Lightning bottom cowl air dam photos Clive, Somewhere around here I have a book that tells about cooling design and eliminating drag. There's a particular ratio that you want to look for between entry area and exit area. The "lip" on the Lightning cowling helps to drop the pressure following it and creates an air pump if you will. It's giving ram effect cooling. Now if you have too little of an opening for the exit the air will tend to build up and spill back out the cowling in front and cause greater cooling drag and less efficiency. If you have too small of an opening in the front for the size of the rear, then you have air pulling through the openings like it should, but not enough quantity to potentially be inadequate. What I would like to see is somebody take it upon their selves, maybe with a background in engineering, and modify their cowling such as this: http://www.airliners.net/photo/Untitled/Lancair-Legacy-2000/0454138/L/ Also see a better view of the bottom of the cowl here: http://www.airliners.net/photo/Untitled/Lancair-Legacy-2000/0647171/L/ The first pic is most applicable. In this case, the air exits via two outlets which shroud the exaust. These protrude into the airstream a little and cause a partial pressure drop. The big drop in pressure comes from the entry/exit sizes though. The air from the cowling exits around the exhaust stacks. The nosegear strut is faired in and glassed to the bottom of the plane. Sure, some of you are going to say, well what about temperature around those exhausts. Temperature will make that pressure drop less than it could if it were cool air and a dedicated duct. Well, the effects of temp on pressure decrease as the mass flow increases, to the point to where it has virtually no impact if you design the cowl right. Having said all of that. The Lightning cowl is very efficient at cooling. It was designed with the entry/exit area in mind. Pete has commented before that if they were to focus on any kind of drag reduction in the future, the cowl would be one of those. It's great at cooling, pretty good in drag, but could be a little better. If some of you engineer types had the know how to modify and do a little testing and present the findings to Arion, if they were favorable to the point of being worthwhile, then you might get a little chance to help make a great design even better! >From the flight testing that I did, it is possible to get a little higher speeds out of the Lightning with simple drag reduction, but you're close to Vne as it is. My focus would be on improving drag and instead of cruising faster, being able to pull the throttle back a little more at high altitude cruise. I think that Earl emailed me that he got 0.2-0.3 gph better fuel burn with his gap seals. It doesn't sound like a lot but if you can get 0.3 here and 0.2 there, then it would be possible to get 4 something gph in cruise in a Lightning and save 10% on fuel costs per year. If you fly 100 hours a year, if gas was $3.50/gallon, it amounts to an additional $175 on fuel. The bigger savings may come in the long run though as you will likely be running cooler and therefore improving the overall life and maintenance cost of the engine. Just a few thoughts. Anybody else have any ideas on the matter. Brian W. ___________________________________________________________ > Subject: FW: Lightning-List: Lightning bottom cowl air dam photos > Date: Fri, 22 Feb 2008 06:55:55 +0000 > From: clive.james@uk.bp.com > To: lightning-list@matronics.com > > Apologies I should have carried on reading the next few posts. Though my > comments still apply. > > Looking at the pictures of the Lightning ducts and my Esquals the size > difference is massive. > > Worth some 'liquid engineering' if there's space. > > Regards, Clive > > -----Original Message----- > From: owner-lightning-list-server@matronics.com > [mailto:owner-lightning-list-server@matronics.com] On Behalf Of > N1BZRich@aol.com > Sent: 21 February 2008 22:07 > To: lightning-list@matronics.com > Subject: Lightning-List: Lightning bottom cowl air dam photos > > Danny, > Right after I sent the previous message I remembered where you could > see the lip on the Lightning's bottom cowl. Go to the Lightning news > web page http://www.arionaircraft.com/News.html, and scroll down to near > the bottom and look at the photos for 1/5/2006, Lightning Cowl > Finalized, and also 2/15/2005, Wheel and gear fairings set for trial. > Both of these set of photos show the lip or air dam. The idea is the > same as on a car. The air dam forces air down and thus creates a lower > pressure area under the bottom cowl. Hope this helps. > Buz > > > > ________________________________ > > Delicious ideas to please the pickiest eaters. Watch the video on AOL > Living. > s-duffy/2050827?NCID=aolcmp00300000002598> _____ Connect and share in new ways with Windows Live. Get it now! ________________________________ Message 5 _____________________________________ Time: 11:49:53 AM PST US Subject: RE: Lightning-List: Lightning bottom cowl air dam photos-Esqual outlet From: "James, Clive R" I would estimate the Esqual outlet is twice the inlet and some. Though I suppose it's how much 'draw' is created by the lip will be a factor in determining what the 'effective' outlet area actually is. Certainly an area to play with when I start chasing the CHT issue, that is if I ever get the papers that are essential for flight! Good feedback folks, Regards, Clive -----Original Message----- From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of flylightning Sent: 22 February 2008 14:51 Subject: RE: Lightning-List: Lightning bottom cowl air dam photos I discussed this at one time with doug from jabiru when he was over here in TN ......about 2.5 times the exit area to inlet area is a good start....this is for a cowl with a lip or fixed down cowl flap if you will.....kent pacer refers to an exit area of 80% of the inlet area which would work well with cruise but not high power low speed in climb...so if you could get 250% exit for take off and close the exit down to 80% for cruise with a movable cowl flap you should have good cooling and reduced drag in cruise.......Hmmm....something for the skunk works on the new demo? Nick ________________________________ From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of Brian Whittingham Sent: Friday, February 22, 2008 1:50 AM Subject: RE: Lightning-List: Lightning bottom cowl air dam photos Clive, Somewhere around here I have a book that tells about cooling design and eliminating drag. There's a particular ratio that you want to look for between entry area and exit area. The "lip" on the Lightning cowling helps to drop the pressure following it and creates an air pump if you will. It's giving ram effect cooling. Now if you have too little of an opening for the exit the air will tend to build up and spill back out the cowling in front and cause greater cooling drag and less efficiency. If you have too small of an opening in the front for the size of the rear, then you have air pulling through the openings like it should, but not enough quantity to potentially be inadequate. What I would like to see is somebody take it upon their selves, maybe with a background in engineering, and modify their cowling such as this: http://www.airliners.net/photo/Untitled/Lancair-Legacy-2000/0454138/L/ Also see a better view of the bottom of the cowl here: http://www.airliners.net/photo/Untitled/Lancair-Legacy-2000/0647171/L/ The first pic is most applicable. In this case, the air exits via two outlets which shroud the exaust. These protrude into the airstream a little and cause a partial pressure drop. The big drop in pressure comes from the entry/exit sizes though. The air from the cowling exits around the exhaust stacks. The nosegear strut is faired in and glassed to the bottom of the plane. Sure, some of you are going to say, well what about temperature around those exhausts. Temperature will make that pressure drop less than it could if it were cool air and a dedicated duct. Well, the effects of temp on pressure decrease as the mass flow increases, to the point to where it has virtually no impact if you design the cowl right. Having said all of that. The Lightning cowl is very efficient at cooling. It was designed with the entry/exit area in mind. Pete has commented before that if they were to focus on any kind of drag reduction in the future, the cowl would be one of those. It's great at cooling, pretty good in drag, but could be a little better. If some of you engineer types had the know how to modify and do a little testing and present the findings to Arion, if they were favorable to the point of being worthwhile, then you might get a little chance to help make a great design even better! >From the flight testing that I did, it is possible to get a little higher speeds out of the Lightning with simple drag reduction, but you're close to Vne as it is. My focus would be on improving drag and instead of cruising faster, being able to pull the throttle back a little more at high altitude cruise. I think that Earl emailed me that he got 0.2-0.3 gph better fuel burn with his gap seals. It doesn't sound like a lot but if you can get 0.3 here and 0.2 there, then it would be possible to get 4 something gph in cruise in a Lightning and save 10% on fuel costs per year. If you fly 100 hours a year, if gas was $3.50/gallon, it amounts to an additional $175 on fuel. The bigger savings may come in the long run though as you will likely be running cooler and therefore improving the overall life and maintenance cost of the engine. Just a few thoughts. Anybody else have any ideas on the matter. Brian W. ___________________________________________________________ > Subject: FW: Lightning-List: Lightning bottom cowl air dam photos > Date: Fri, 22 Feb 2008 06:55:55 +0000 > From: clive.james@uk.bp.com > To: lightning-list@matronics.com > > Apologies I should have carried on reading the next few posts. Though > my comments still apply. > > Looking at the pictures of the Lightning ducts and my Esquals the size > difference is massive. > > Worth some 'liquid engineering' if there's space. > > Regards, Clive > > -----Original Message----- > From: owner-lightning-list-server@matronics.com > [mailto:owner-lightning-list-server@matronics.com] On Behalf Of > N1BZRich@aol.com > Sent: 21 February 2008 22:07 > To: lightning-list@matronics.com > Subject: Lightning-List: Lightning bottom cowl air dam photos > > Danny, > Right after I sent the previous message I remembered where you could > see the lip on the Lightning's bottom cowl. Go to the Lightning news > web page http://www.arionaircraft.com/News.html, and scroll down to > near the bottom and look at the photos for 1/5/2006, Lightning Cowl > Finalized, and also 2/15/2005, Wheel and gear fairings set for trial. > Both of these set of photos show the lip or air dam. The idea is the > same as on a car. The air dam forces air down and thus creates a lower > pressure area under the bottom cowl. Hope this helps. > Buz > > > > ________________________________ > > Delicious ideas to please the pickiest eaters. Watch the video on AOL > Living. > po s-duffy/2050827?NCID=aolcmp00300000002598> ________________________________ Connect and share in new ways with Windows Live. Get it now! http://www.matronics.com/contribution ________________________________ Message 6 _____________________________________ Time: 11:35:22 PM PST US From: Brian Whittingham Subject: RE: Lightning-List: Lightning bottom cowl air dam photos Those numbers sound about right. Seems like 2.5 is about what the Lightnin g has. My book on aircraft design actually states that there is no need fo r cowl flaps if the cowling is designed perfectly. The catch is, with any of us who are not privy to a wind tunnel and sophisticated testing equipmen t, is that requires a lot of design, fabrication, re-design, and refab. It 's more of a trial and error. The trick these days is to create the desire d flow through the engine, and resulting pressure drop associated with that to adequately cool the engine. Another challenge is that all engines aren 't created the same. So a lycoming under one cowling may only need a redes ign to get an additional 5 degrees and a Jabiru may require a drop of 15 de grees, or vice-versa. Again, having said that, the Lightning has a good trade off between cooling and drag. Still, it may be worth working on in the off-time, when you get some more of these improvements on and tested. It's kind of like the chan ge in NACA ducts for the oil cooler that happened early on in the design. We got a large drop in oil temps. The duct looked virtually the same as th e old duct, but the aero was desidedly different. Brian W. From: info@flylightning.netTo: lightning-list@matronics.comSubject: RE: Lig htning-List: Lightning bottom cowl air dam photosDate: Fri, 22 Feb 2008 08: 50:52 -0600 I discussed this at one time with doug from jabiru when he was over here in TN =85=85about 2.5 times the exit area to inlet area is a good start=85.t his is for a cowl with a lip or fixed down cowl flap if you will=85..kent p acer refers to an exit area of 80% of the inlet area which would work well with cruise but not high power low speed in climb=85so if you could get 250 % exit for take off and close the exit down to 80% for cruise with a movabl e cowl flap you should have good cooling and reduced drag in cruise=85=85.H mmm=85.something for the skunk works on the new demo? Nick From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-lis t-server@matronics.com] On Behalf Of Brian WhittinghamSent: Friday, Februar y 22, 2008 1:50 AMTo: lightning-list@matronics.comSubject: RE: Lightning-Li st: Lightning bottom cowl air dam photos Clive, Somewhere around here I have a book that tells about cooling desig n and eliminating drag. There's a particular ratio that you want to look f or between entry area and exit area. The "lip" on the Lightning cowling he lps to drop the pressure following it and creates an air pump if you will. It's giving ram effect cooling. Now if you have too little of an opening for the exit the air will tend to build up and spill back out the cowling i n front and cause greater cooling drag and less efficiency. If you have to o small of an opening in the front for the size of the rear, then you have air pulling through the openings like it should, but not enough quantity to potentially be inadequate. What I would like to see is somebody take it u pon their selves, maybe with a background in engineering, and modify their cowling such as this: http://www.airliners.net/photo/Untitled/Lancair-Legac y-2000/0454138/L/ Also see a better view of the bottom of the cowl here: ht tp://www.airliners.net/photo/Untitled/Lancair-Legacy-2000/0647171/L/ The fi rst pic is most applicable. In this case, the air exits via two outlets wh ich shroud the exaust. These protrude into the airstream a little and caus e a partial pressure drop. The big drop in pressure comes from the entry/e xit sizes though. The air from the cowling exits around the exhaust stacks . The nosegear strut is faired in and glassed to the bottom of the plane. Sure, some of you are going to say, well what about temperature around tho se exhausts. Temperature will make that pressure drop less than it could i f it were cool air and a dedicated duct. Well, the effects of temp on pres sure decrease as the mass flow increases, to the point to where it has virt ually no impact if you design the cowl right. Having said all of that. T he Lightning cowl is very efficient at cooling. It was designed with the e ntry/exit area in mind. Pete has commented before that if they were to foc us on any kind of drag reduction in the future, the cowl would be one of th ose. It's great at cooling, pretty good in drag, but could be a little bet ter. If some of you engineer types had the know how to modify and do a lit tle testing and present the findings to Arion, if they were favorable to th e point of being worthwhile, then you might get a little chance to help mak e a great design even better! >From the flight testing that I did, it is possible to get a little higher speeds out of the Lightning with simple dra g reduction, but you're close to Vne as it is. My focus would be on improv ing drag and instead of cruising faster, being able to pull the throttle ba ck a little more at high altitude cruise. I think that Earl emailed me tha t he got 0.2-0.3 gph better fuel burn with his gap seals. It doesn't sound like a lot but if you can get 0.3 here and 0.2 there, then it would be pos sible to get 4 something gph in cruise in a Lightning and save 10% on fuel costs per year. If you fly 100 hours a year, if gas was $3.50/gallon, it a mounts to an additional $175 on fuel. The bigger savings may come in the l ong run though as you will likely be running cooler and therefore improving the overall life and maintenance cost of the engine. Just a few thoughts. Anybody else have any ideas on the matter. Brian W. ____________________ _______________________________________> Subject: FW: Lightning-List: Light ning bottom cowl air dam photos> Date: Fri, 22 Feb 2008 06:55:55 +0000> Fro m: clive.james@uk.bp.com> To: lightning-list@matronics.com> > Apologies I s hould have carried on reading the next few posts. Though my> comments still apply. > > Looking at the pictures of the Lightning ducts and my Esquals t he size> difference is massive.> > Worth some 'liquid engineering' if there 's space.> > Regards, Clive> > -----Original Message-----> From: owner-ligh tning-list-server@matronics.com> [mailto:owner-lightning-list-server@matron ics.com] On Behalf Of> N1BZRich@aol.com> Sent: 21 February 2008 22:07> To: lightning-list@matronics.com> Subject: Lightning-List: Lightning bottom cow l air dam photos> > Danny,> Right after I sent the previous message I remem bered where you could> see the lip on the Lightning's bottom cowl. Go to th e Lightning news> web page http://www.arionaircraft.com/News.html, and scro ll down to near> the bottom and look at the photos for 1/5/2006, Lightning Cowl> Finalized, and also 2/15/2005, Wheel and gear fairings set for trial. > Both of these set of photos show the lip or air dam. The idea is the> sam e as on a car. The air dam forces air down and thus creates a lower> pressu re area under the bottom cowl. Hope this helps.> Buz> > > > _______________ _________________> > Delicious ideas to please the pickiest eaters. Watch t he video on AOL> Living.> s-duffy/2050827?NCID=aolcmp00300000002598> Connect and share in new ways with Windows Live. Get it now! http://www.m atronics.com/contribution _________________________________________________________________ Climb to the top of the charts!-Play the word scramble challenge with sta r power. http://club.live.com/star_shuffle.aspx?icid=starshuffle_wlmailtextlink_ja n ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message lightning-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Lightning-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/lightning-list Browse Digests http://www.matronics.com/digest/lightning-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.