---------------------------------------------------------- RV10-List Digest Archive --- Total Messages Posted Mon 03/04/13: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:07 AM - Re: Behind the curve, was RV-10 Stall Characteristics (jkreidler) 2. 06:26 AM - Re: go pro mounts (Richard Barnes) 3. 09:32 AM - Re: go pro mounts (Robin Marks) 4. 09:47 AM - Certifying the RV-10 (rleffler) 5. 10:40 AM - Composites for RV-10s Class (Carlos Trigo) 6. 11:04 AM - Re: Behind the curve, was RV-10 Stall Characteristics (Bob Turner) 7. 01:03 PM - Re: Behind the curve, was RV-10 Stall Characteristics (jkreidler) 8. 01:39 PM - Re: Behind the curve, was RV-10 Stall Characteristics (Bob Turner) 9. 06:28 PM - Re: go pro mounts (Strasnuts) 10. 06:50 PM - Re: Behind the curve, was RV-10 Stall Characteristics (jkreidler) 11. 07:50 PM - Re: Composites for RV-10s Class (Dave Saylor) 12. 07:50 PM - Re: Behind the curve, was RV-10 Stall Characteristics (Bob Turner) 13. 08:32 PM - Re: RV-10 down (rv10flyer) ________________________________ Message 1 _____________________________________ Time: 06:07:59 AM PST US Subject: RV10-List: Re: Behind the curve, was RV-10 Stall Characteristics From: "jkreidler" All, one of the best books around to explain all of this is "Aerodynamic for Naval Aviators". The book is available for free download on the FAA's web site at the address below. Actually they have a number of free books with good info, check out: http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/ http://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/00-80T-80.pdf Since nearly every build eventually becomes a test pilot it is a good idea to understand the basics. Please know that below is my interpretation of behind the curve, I do not have formal training in aerodynamics but I did stay at a Holiday Inn Express. If you look at page 42 of the PDF (book page 24) you see a plot of the coefficient of lift (CL) relative to the angle of attack (AOA). At the top of the curve the AOA increases while the CL decreases up until the wing stalls. This is one aspect of 'behind the curve'. The second aspect of 'behind the curve' is found on pages 46 & 47 of the PDF (book pages 28 & 29), where they talk about the drag coefficient (CD) relative to lift (L/D). This says that as the AOA is increased the CD will increase. The AOA which yields the best L/D is called L/D Max (the most lift for the least drag), at AOAs greater than what produces L/D Max you are using more AOA to produce less lift with more drag until stall. The powerplant (gravity or Lycoming) needs to provide extra power to overcome the extra drag to produce lift. You will notice that everything refers to angle of attack and not airspeed as a wing will always act the same at a certain angle of attack, not true with airspeed. Which is one reason why AOA indicators are such neat tools; they help you know where the edge is rather than trying to predict the edge based on airspeed combined with other factors. One last point from page 46 of the PDF (28 of the book) notice the differences in shapes of the curves for different airfoils. Some of the curves have fairly flat backsides (NACA 63-006), while some have dramatic drop offs (NACA 63-009). The flat backs are typical of training aircraft where the back side of the curve wasnt as bad. Our RVs have steeper backsides as a result of the tradeoffs made to get a good high speed wing with low stall speeds. This is something that gets new RV pilots sometimes when they get on the backside, they are not as used to how much power it can take to correct a fast sink, remember that power can come from Lycoming or gravity, push the throttle or the stick, but it has got to happen quicker and more aggressively than that trainer we all got used to. I do not have a plot for the RV-10 sorry. Feel free to correct me on this, as I said I do not have formal training in this area of engineering. Beyond that please take some time to investigate this for yourselves, you may learn something, or at very least find a cure to insomnia. Above all please continue to share with the group things that surprised you, I have not experienced this one first hand, but I remember when a slip nearly got me (see the archives). Thanks Jason -------- Jason Kreidler 4 Partner Build - Sheboygan Falls, WI Tony Kolar, Kyle Hokel, Wayne Elser, Jason Kreidler N44YH - Flying - #40617 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395586#395586 ________________________________ Message 2 _____________________________________ Time: 06:26:33 AM PST US From: "Richard Barnes" Subject: RE: RV10-List: go pro mounts Robin, I particularly like the 4K Panasonic playback monitor for $500,000.00. Rick From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Robin Marks Sent: Sunday, March 03, 2013 8:52 PM Subject: RE: RV10-List: go pro mounts Hay Sean (303), I have been playing with these cams for some time. I don't have experience with all of the cameras but I do have time with most form factors. While the NFCam is a nice unit I do suggest you give the GoPro strong consideration for a number of reasons. First the new GoPro is a wonderful design and very good quality. GoPro has built a really good platform including the ability to link a couple of units for both 3D and 4K filming. If you don't know what 4K is you will in a few years. I have been in conversations with a fellow doing some amazing air footage from his Velocity with something like 11 GoPro cams mounted to his bird. The images are amazing. The waterproof housing and apple/android integration are also a bonus. Throw in the best remote of all the cameras and you have a pretty compelling package. Plus much like the RV list there is a GoPro community that is unmatched by any other action camera company. Another advantage to GoPro is one of the owners of FoxConn (where you cell phone was probably made) just dropped $200 MM into GoPro for 8% of the company valuing it at over a billion dollars. That means the GoPro eco system is probably only going to get more robust. I was just in FL on a wave runner doing a self-tape movie through a ski slalom course. I used the chest mount, head mount, reversed the chest mount for a trailing video. Held the cam very close to the waterline fore & aft for a cool speed effect. Not too many action cam's would be comfortable or safe in that environment. It was no problem with the GP. Ultra easy to use with the waterproof housing. 1080P 48 FPS video looks pure! I am part way through editing and the video could be used in a theater setting. Good luck, Robin -----Original Message----- From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Sean Stephens Sent: Sunday, March 03, 2013 5:09 PM Subject: Re: RV10-List: go pro mounts sean@stephensville.com> Speaking of GoPro, I am about to purchase a vid cam for inside the cockpit. I've been researching the GoPro and also the NflightCam. http://www.sportys.com/Pilotshop/product/16638 The thing I like about the nflightcam is the special lens which reduces the prop blur effect. Has anyone tried both? If so, plus and minus? Thanks, -Sean #40303 On 3/3/13 6:07 PM, Dave Bowman wrote: > --> < davidbowman1@verizon.net> > > I'm interested > Dave Bowman > 40831 > N831DB Flying > > -----Original Message----- From: Strasnuts > Sent: Sunday, March 03, 2013 9:58 AM > To: rv10-list@matronics.com > Subject: RV10-List: go pro mounts > sean@braunandco.com> > > If anyone is interested let me know. I may start making more. I have > this style of mount which can be used on the wing tie-downs or tail > tie-down. I also have a fuel cap mount I'm still testing which can > move any direction before flight by simply turning the cap. attached > is a pic of the tie down mount. It is made of steel. > > -------- > 40936 > RV-10 SB N801VR Flying > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=395516#395516 > > > > > Attachments: > > http://forums.matronics.com//files/goprp_mount_771.jpg > > > > > > > > > > =================== bsp; - The RV10-List Email Forum - nd much much more: tronics.com/Navigator?RV10-List"> http://www.matronics.com/Navigator?RV10-List =================== bsp; - MATRONICS WEB FORUMS - eb Forums! .matronics.com">http://forums.matronics.com =================== bsp; - List Contribution Web Site - o:p> bsp; -Matt Dralle, List Admin. tronics.com/contribution"> http://www.matronics.com/contribution =================== ----- No virus found in this message. Checked by AVG - www.avg.com - Release Date: 03/03/13 ________________________________ Message 3 _____________________________________ Time: 09:32:24 AM PST US From: Robin Marks Subject: Re: RV10-List: go pro mounts Yes, it's ok for a kitchen TV but I would not have one in my living room. : -) Robin Do not archive Sent from my iPad2. On Mar 4, 2013, at 6:42 AM, "Richard Barnes" > wrote: Robin, I particularly like the 4K Panasonic playback monitor for $500,000.00. Rick From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Rob in Marks Sent: Sunday, March 03, 2013 8:52 PM Subject: RE: RV10-List: go pro mounts Hay Sean (303), I have been playing with these cams for some time. I don't have experience with all of the cameras but I do have time with most form factors. While th e NFCam is a nice unit I do suggest you give the GoPro strong consideration for a number of reasons. First the new GoPro is a wonderful design and ver y good quality. GoPro has built a really good platform including the abilit y to link a couple of units for both 3D and 4K filming. If you don=92t know what 4K is you will in a few y ears. I have been in conversations with a fellow doing some amazing air foo tage from his Velocity with something like 11 GoPro cams mounted to his bir d. The images are amazing. The waterproof housing and apple/android integra tion are also a bonus. Throw in the best remote of all the cameras and you have a pretty compelling package. Plus much like the RV list there is a GoP ro community that is unmatched by any other action camera company. Another advantage to GoPro is one of the owners of FoxConn (where you cell phone was probably made) just dropped $200 MM into GoPro for 8% of the company valuing it at over a billion dollars. That means the GoPro eco system is probably only going to get more robust. I was just in FL on a wave runner doing a self-tape movie through a ski sla lom course. I used the chest mount, head mount, reversed the chest mount fo r a trailing video. Held the cam very close to the waterline fore & aft for a cool speed effect. Not too many action cam's would be comfortable or saf e in that environment. It was no problem with the GP. Ultra easy to use wit h the waterproof housing. 1080P 48 FPS video looks pure! I am part way thro ugh editing and the video could be used in a theater setting. Good luck, Robin -----Original Message----- From: owner-rv10-list-server@matronics.com [mailto:owner-rv10-list-server@matronics.com] On Behalf Of Sea n Stephens Sent: Sunday, March 03, 2013 5:09 PM Subject: Re: RV10-List: go pro mounts to:sean@stephensville.com>> Speaking of GoPro, I am about to purchase a vid cam for inside the cockpit. I've been researching the GoPro and also the NflightCam. http://www.sportys.com/Pilotshop/product/16638 The thing I like about the nflightcam is the special lens which reduces the prop blur effect. Has anyone tried both? If so, plus and minus? Thanks, -Sean #40303 On 3/3/13 6:07 PM, Dave Bowman wrote: > --> > > > I'm interested > Dave Bowman > 40831 > N831DB Flying > > -----Original Message----- From: Strasnuts > Sent: Sunday, March 03, 2013 9:58 AM > To: rv10-list@matronics.com > Subject: RV10-List: go pro mounts > sean@braunandco.com>> > > If anyone is interested let me know. I may start making more. I have > this style of mount which can be used on the wing tie-downs or tail > tie-down. I also have a fuel cap mount I'm still testing which can > move any direction before flight by simply turning the cap. attached > is a pic of the tie down mount. It is made of steel. > > -------- > 40936 > RV-10 SB N801VR Flying > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=395516#395516 > > > > > Attachments: > > http://forums.matronics.com//files/goprp_mount_771.jpg > > > > > > > > > > =================== bsp; - The RV10-List Email Forum - nd much much more: tronics.com/Navigator?RV10-List"> h ttp://www.matronics.com/Navigator?RV10-List =================== bsp; - MATRONICS WEB FORUMS - eb Forums! .matronics.com">http://forums.matronics.com =================== bsp; - List Contribution Web Site - o:p> bsp; -Matt Dralle, List Admin. tronics.com/contribution"> http://www.matr onics.com/contribution =================== ----- No virus found in this message. Checked by AVG - www.avg.com - Release Date: 03/03/13 http://www.matronics.com/Navigator?RV10-List http://forums.matronics.com http://www.matronics.com/contribution ________________________________ Message 4 _____________________________________ Time: 09:47:03 AM PST US Subject: RV10-List: Certifying the RV-10 From: "rleffler" An one sided debate on certifying the RV-10 on the red board. http://forums.aopa.org/showthread.php?t=86327 Some of the responses are pretty comical and truly uninformed. bob -------- Bob Leffler N410BL - Paint - 90% done, 90% to go stage RV-10 #40684 http://mykitlog.com/rleffler Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395611#395611 ________________________________ Message 5 _____________________________________ Time: 10:40:40 AM PST US From: "Carlos Trigo" Subject: RV10-List: Composites for RV-10s Class Hello all This is a brief note to publicly thank the guys from Aircrafters, in Watsonville - CA, to where I travelled several thousand miles to attend their class on Composites for the RV-10. It was time and money well spent, I learned a lot of tips that will help me to do a much better job with the fiberglass parts (and there are plenty.). I also met a bunch of fellow homebuilders, we exchanged experiences and some ideas, not only on the FB subject itself. Thank you Dave Saylor and Tim Farrell Best Carlos Trigo P.S. - ah, well, and also had the opportunity to have a demo flight on Dave's -10. Thanks Dave Pretty fun and very useful stay at Watsonville. ________________________________ Message 6 _____________________________________ Time: 11:04:46 AM PST US Subject: RV10-List: Re: Behind the curve, was RV-10 Stall Characteristics From: "Bob Turner" Jason, since you said it's okay to offer some corrections... One of the hardest concepts for physics students to grasp is that when they're holding a big rock in front of them, they are in fact doing no work (in the physics sense), since work (also called energy) requires a force acting through a distance. Power (which is energy per second) cannot be directly compared to lift or drag, which are forces. So L/D max (I find it easiest to think of the lift fixed at the airplane's weight, and the drag varying) is where the least force is required to keep the airplane in unaccelerated flight. But it is not where the least power is required, because at slightly lower speeds the force is slightly greater, but the distance per time (speed) is lower, and the product of the two (power) is less. So you end up with minimum sink (minimum power required) speed being less than best glide speed. Remember best glide is not an attempt to minimize power, but rather to maximize the ratio of forward distance traveled over vertical distance lost. In some ways comparable to the fact that maximum range speed is higher than maximum endurance speed. So you don't get behind the power curve (the region where it takes more power to maintain level flight as you go slower) until you are slower than minimum sink speed, which, as I said, is 0.76 (fourth root of 1/3) slower than best L/D speed for an ideal plane. -------- Bob Turner RV-10 QB Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395619#395619 ________________________________ Message 7 _____________________________________ Time: 01:03:04 PM PST US Subject: RV10-List: Re: Behind the curve, was RV-10 Stall Characteristics From: "jkreidler" Thanks Bob - let me say this a bit differently, maybe we are saying the same thing. As you reduce power to slow down and increase AOA to maintain level flight you will continue to reduce drag, at some point (L/D Max) the drag will again start to increase, which is the point you have moved to the backside of the curve. You will need further increase AOA and increase power to maintain level flight, until you slow to a speed where maximum AOA is reached and the wing stalls regardless of power setting. Important to note the distinction, before reaching L/D Max you can decrease power, increase AOA and maintain altitude, after passing L/D Max you will need to increase power and AOA to hold altitude. The higher power setting is required to offset the increased drag. In order to get out of the stall we need to reduce the AOA either by adding enough power to overcome the drag plus the power needed to alter the relative wind (AOA), or by pushing the nose over to alter the relative wind (AOA) ideally both. Question on the formula you sight, is that good for all types of airplanes, or is the number different for say a Cessna versus a Cirrus? Either way thanks for the feedback, and by all means let me (and the group know) if I still dont get it, I am not sure I fully understand you distinction between power and force as it applies here, from a theoretical standpoint I understand perfectly. I guess when I say power I am referring to engine settings, maybe not the best form. -------- Jason Kreidler 4 Partner Build - Sheboygan Falls, WI Tony Kolar, Kyle Hokel, Wayne Elser, Jason Kreidler N44YH - Flying - #40617 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395625#395625 ________________________________ Message 8 _____________________________________ Time: 01:39:21 PM PST US Subject: RV10-List: Re: Behind the curve, was RV-10 Stall Characteristics From: "Bob Turner" Jason, not quite right yet. Power is calculated by multiplying the force times the velocity. I know it is not intuitive but you can get away with less power by slowing down, even though the drag force goes up. To make up numbers for the airplane, suppose at best L/D the force required to overcome the drag is 100 lbs, and the speed is 80 knots. The power required is 8000 (in some strange units). Now if you slow to 70 knots, the drag is up to, say 110 lbs. But the power required is lower, 7700 (same strange units), than it was at best L/D, because while the drag force went up, it went up more slowly than the speed went down. As you go still slower, the rate of increase of drag gets larger, and eventually it goes up faster than speed goes down. That's minimum sink speed, and slower than that you have the strange phenomenon that level flight requires more power if you want to go even slower. BTW, as speed goes to zero power required goes to infinity, not zero, because the drag goes to infinity "faster" than the speed goes to zero. The usual ideal airplane model approximations are: parasitic drag proportional to v squared; wing lift proportional to angle of attack and v squared, and equal to weight, induced drag equal to angle of attack times weight which makes induced drag proportional to one divided by v squared. When you multiply the force (drag) by v to get power you end up with terms that are proportional to v cubed and 1/v. When you solve this equation you'll end up with v to the fourth, that's where the fourth root comes from. When you differentiate the v cubed term (to find the minimum) it becomes 3 v squared; that's where the 3 comes from. Minimum sink is fourth root of 1/3 times best glide. This is all a lot simpler if you can find graphs of "Power required" and "power available (including prop efficiency)". -------- Bob Turner RV-10 QB Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395627#395627 ________________________________ Message 9 _____________________________________ Time: 06:28:48 PM PST US Subject: RV10-List: Re: go pro mounts From: "Strasnuts" Another mount we made and worked great. You can just turn your fuel cap to view the fuse. I may make this as a one piece unit to replace the top of the cap instead of Drilling and tapping your cap like I did. -------- 40936 RV-10 SB N801VR Flying Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395655#395655 Attachments: http://forums.matronics.com//files/photo_3_214.jpg http://forums.matronics.com//files/photo_1_113.jpg http://forums.matronics.com//files/photo_4_165.jpg http://forums.matronics.com//files/photo_2_152.jpg ________________________________ Message 10 ____________________________________ Time: 06:50:36 PM PST US Subject: RV10-List: Re: Behind the curve, was RV-10 Stall Characteristics From: "jkreidler" Have a look at the Naval Aviators Handbook starting on page 353 - they explain operating on the backside of the curve (region of reverse command). They reference power as thrust. You are going a bit further and talking about energy management. Thanks for your help in understanding this Bob - Jason -------- Jason Kreidler 4 Partner Build - Sheboygan Falls, WI Tony Kolar, Kyle Hokel, Wayne Elser, Jason Kreidler N44YH - Flying - #40617 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395657#395657 ________________________________ Message 11 ____________________________________ Time: 07:50:15 PM PST US From: Dave Saylor Subject: Re: RV10-List: Composites for RV-10s Class Thank you Carlos for your kind words. It was a good class with nine participants. We demonstrated fitting a cabin cover and several other items. Everyone got to mix some resin and play around with various materials. And only one mild case of exotherming. Dave Saylor 831-750-0284 CL Do Not Archive On Mon, Mar 4, 2013 at 10:38 AM, Carlos Trigo wrote: > Hello all > > > This is a brief note to publicly thank the guys from Aircrafters, in > Watsonville CA, to where I travelled several thousand miles to attend > their class on Composites for the RV-10. > > It was time and money well spent, I learned a lot of tips that will help me > to do a much better job with the fiberglass parts (and there are plenty). > > I also met a bunch of fellow homebuilders, we exchanged experiences and some > ideas, not only on the FB subject itself. > > > Thank you Dave Saylor and Tim Farrell > > Best > > Carlos Trigo > > > P.S. ah, well, and also had the opportunity to have a demo flight on > Daves -10. Thanks Dave > > Pretty fun and very useful stay at Watsonville > > ________________________________ Message 12 ____________________________________ Time: 07:50:16 PM PST US Subject: RV10-List: Re: Behind the curve, was RV-10 Stall Characteristics From: "Bob Turner" Yes, that's a good reference. Look at the graph of power required at the bottom of page 98. It shows how minimum power occurs at a lower speed than max L/D, and in fact is about 0.8 less. This reference frequently mixes turbojet engines with propeller driving engines. There are some important differences, explained around page 96 and following. Turbojets tend to put out constant thrust regardless of speed ( and so put out more power at higher speeds), while our internal combustion engines put out constant power, not changing with speed (actually we can get a small amount of extra power at higher speeds due to ram air pushing the manifold pressure up a bit). -------- Bob Turner RV-10 QB Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395660#395660 ________________________________ Message 13 ____________________________________ Time: 08:32:08 PM PST US Subject: RV10-List: Re: RV-10 down From: "rv10flyer" http://www.aviationinspector.com/?p=13785 -------- Wayne G. SB 12/01/2009-12/01/2011 TT= 97.6 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=395662#395662 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rv10-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RV10-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/rv10-list Browse Digests http://www.matronics.com/digest/rv10-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.