---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 04/13/18: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:44 AM - Re: Re: Charging Issue (FLYaDIVE) 2. 05:35 AM - Re: Diy AOA, anyone ? (andymeyer) 3. 06:15 AM - Re: Re: Diy AOA, anyone ? (FLYaDIVE) 4. 06:21 AM - Re: Car clock in an aircraft (Bill Watson) 5. 06:28 AM - Re: Diy AOA, anyone ? (Ernest Christley) 6. 07:10 AM - Re: Diy AOA, anyone ? (user9253) 7. 07:24 AM - Re: Re: Diy AOA, anyone ? (FLYaDIVE) 8. 07:45 AM - Re: Re: Diy AOA, anyone ? (Alec Myers) 9. 08:34 AM - Re: Re: Diy AOA, anyone ? (Bob Verwey) 10. 12:19 PM - Re: Diy AOA, anyone ? (user9253) 11. 02:19 PM - Re: Re: Diy AOA, anyone ? (Alec Myers) 12. 04:02 PM - Re: Re: Diy AOA, anyone ? (Richard Girard) ________________________________ Message 1 _____________________________________ Time: 04:44:48 AM PST US From: FLYaDIVE Subject: Re: AeroElectric-List: Re: Charging Issue Matt: How is a crack in a feed-through causing a voltage drop? If it was shorting out a CB would pop. You did not give p/n so I do not know if it is a grommet feed through or a terminal type feed through. If it was a grommet, that would also mean the insulation on the wire failed. If it is a terminal type a simple thing like a poor connection could be causing the problem. Without seeing the setup I am assuming (I hate that word) that all is well with: Connections Connectors Crimps and Materials. RULE: You can not tell if there is corrosion on a connection unless you open the connection and clean the contact areas. Also, replace the Lock Washers with Star Lock Washers. Replace them every time you undo the connection. The lock washers have to cut into the faces of the mating surfaces. Alternator Noise is fairly easy to solve. I say 'fairly easy' because I do not know your wiring. I use 25,000 uF @ 16 WVDC Electrolytic Caps. <-- Only because I have a box full of them and they work. If you want to go bigger... Have at it! 'It's all good baby!' Positive to the hot lead. Negative to Ground. Put in very close to the B+ output of the Alternator. Keep the leads as short as possible. Second location for the same size Cap. At the ACU. Between the 'A' lead [the lead coming from alternator B+ to the ACU]. Again, keep the leads as short as possible. DO NOT STRAIN THE WIRES. Many alternators use a automotive looking/type Cap that has only one lead which goes to the B+ and the body of the Cap is mounted to ground. If you purchase this type of Cap from the auto store. <-- The value is no where near that of the electrolytic. It handles a different frequency. 1 - Make sure the mounting tab/clamp is WELDED to the body of the Cap. 2 - The mounting hole is a HOLE! Not 'U' cutout. This makes mounting extremely easy and pretty much eliminates the Cap from coming loose. If you have access to a O Scope you can hook it up to each of the wires: B+ Field Ground And see exactly which wire is carrying the noise AND what frequency it is. When even ONE diode in the alternators diode pack fails the noise becomes present. If that is the case you will hear the noise change in frequency as the engine is increased and decreased in RPM. It may even change in amplitude. If that is what you are seeing (O Scope) and hearing (Headset), then the Caps will decrease the problem but NOT eliminate it. Repair/Replace the alternator. Barry On Tue, Apr 10, 2018 at 8:48 PM, mhealydds wrote: > > I was the original poster and found my issue. I had a cracked firewall > passthrough fitting (it was Blue Sea fitting a lot of other RV-10 user > reported using). Anyway, it was in a spot not easy to inspect and never > thought about it being cracked, just he connections on the fitting. Now a > have a bad alternator noise I have thing to track down. Anyone dealt with > that? > > Matt > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=479250#479250 > > ________________________________ Message 2 _____________________________________ Time: 05:35:37 AM PST US Subject: AeroElectric-List: Re: Diy AOA, anyone ? From: "andymeyer" I am about to embark on such a device... I do have a few sensors that I'm exploring - https://www.mouser.com/ProductDetail/NXP/MPXV5004DP/?qs=r8OyiFxb6Rd0SEc8C8FTtQ%3D%3D&gclid=Cj0KCQjwqsHWBRDsARIsALPWMEPR9lBEDtFAgUCnJAyuzfox0BoKwWSAPuJzr-_TL6mzXtmxLWp3dcMaAjfiEALw_wcB Looks pretty dang close for the pressure sensing. Do you know how much deltaP we are expecting at sub 200 knots indicated based on your previous work? I've got to finish my airspeed sensing for my engine monitor / air data computer first, then on to AOA. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479302#479302 ________________________________ Message 3 _____________________________________ Time: 06:15:22 AM PST US From: FLYaDIVE Subject: Re: AeroElectric-List: Re: Diy AOA, anyone ? Hi Andy: I worked on an RV6A which had this AOA unit: http://www.aircraftspruce.com/catalog/inpages/aoasportsystemaluminum.php?clickkey=5477 It required and used sensing holes on the top and bottom of the wing. Maybe... If you give them a call... NOT ACS! They maybe able to answer the question. Barry On Fri, Apr 13, 2018 at 8:34 AM, andymeyer wrote: > > > > I am about to embark on such a device... > I do have a few sensors that I'm exploring - > https://www.mouser.com/ProductDetail/NXP/MPXV5004DP/? > qs=r8OyiFxb6Rd0SEc8C8FTtQ%3D%3D&gclid=Cj0KCQjwqsHWBRDsARIsALPWMEPR9l > BEDtFAgUCnJAyuzfox0BoKwWSAPuJzr-_TL6mzXtmxLWp3dcMaAjfiEALw_wcB > Looks pretty dang close for the pressure sensing. Do you know how much > deltaP we are expecting at sub 200 knots indicated based on your previous > work? > > I've got to finish my airspeed sensing for my engine monitor / air data > computer first, then on to AOA. > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=479302#479302 > > ________________________________ Message 4 _____________________________________ Time: 06:21:41 AM PST US Subject: Re: AeroElectric-List: Car clock in an aircraft From: Bill Watson Agreed. And if it's needed, don't put it on an always-on bus. I had this situation with an earlier GRT unit that had an internal clock that required an always-on connection. Actually I had 3 units... the combined drain slowly but surely killed my AGM battery. They don't like that kind of treatment (there's slightly more to the story). But I would say "don't connect anything to always-on unless critical... then question why that product is in your plane". On 4/11/2018 10:26 AM, jim@poogiebearranch.com wrote: > > Hm. If it works without being wired in, why not just leave it powered > by the button cell batteries? Seems like a "non-essential" item to me, > and I would hate for there to be ANY possibility it might drain the > battery over time. > > Jim Parker > > > -------- Original Message -------- > Subject: AeroElectric-List: Car clock in an aircraft > From: Carlos Trigo > Date: Tue, April 10, 2018 4:40 pm > To: aeroelectric-list@matronics.com > > > > To the electrowizzards in this list. > (This is not a rocket science aircraft subject, but I need your help on > this) > > I bought one of those cheap (chinese) digital car clocks, with > temperature indication, to install in the back of my RV-10, as a > courtesy to the rear passengers. (please avoid any comments on this > decision... :-)). > As one could expect, the miserable instructions leaflet which came with > the clock, doesnt have any information about the electric circuit, so > Im in the guess field here. > > This critter has a 2-wire cable to be connected to 12V/24V, and also has > 2 of those coin type batteries, so I suppose that the batteries are a > backup to the ships power. > But Im not sure... > > This leaves me with a doubt on where to connect the + wire of the power > cable. > Should I connect it to a circuit which is only powered when the aircraft > Master switch is on, to avoid this critter to deplete the aircraft > battery? > Or can I connect it to the always hot bus, hoping that when the Master > is Off, the clocks coin batteries will be powering the clock and only > a very tiny current will be draining from the always hot bus, not > depleting the aircrafts battery? > > Even knowing that without information on the clocks electric circuit > it is difficult to know the answer, comments and suggestions are welcome > > Thanks > Carlos > > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 5 _____________________________________ Time: 06:28:20 AM PST US From: Ernest Christley Subject: Re: AeroElectric-List: Diy AOA, anyone ? I cut the corner off a piece of 1/2" plate of aluminum. =C2-With it orien ted so the 90 degree angle is at the top right, I drilled a 1/4" hole halfw ay through from the top, and a 1/16" hole from the left that intersected wi th the 1/4" hole. =C2-I got the "homebuilder's pitot/static" from ACS. =C2-It's the one with two pieces of 1/4" tube tack welded into a base. =C2-I drilled a 1/4" hole through the base behind the others, then ran a 8" or so length of 1/4" tube through it and into the top of the triangle. =C2-Situated it so that the triangle touched the bottom of the previous t ubes, then buried the assembly in a peanut butter thick mix of micro. =C2 -Let it set, sanded it to an "airfoilish" shape, and wrapped it in a 9oz layer of glass. Works fine with my Dynon-100 AoA. On Thursday, April 12, 2018 11:17 PM, GTH wrote : Hi all, One of my building buddies just challenged me concerning the following Pitot angle of attack (AOA) device https://www.thingiverse.com/thing:1121786 Of course 3D printing the device is the easiest part. But does anyone here happen to have implemented, programmed, etc. an AOA indicator, and with what success ? BTW, some years ago I had the opportunity to make a study for such a device based on differential pressure between upper and lower wing surface. At the time the study involved a University wind tunnel, hotwire profiles, several students, but nowadays my approach needs to be much much "lower tech" as I no longer have access to such facilities. Thanks for your inputs, -- Best regards, Gilles http://contrails.free.fr http://lapierre.skunkworks.free.fr - S - WIKI - - =C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin. ________________________________ Message 6 _____________________________________ Time: 07:10:55 AM PST US Subject: AeroElectric-List: Re: Diy AOA, anyone ? From: "user9253" An AOA probe can be made using only a single pop rivet with the mandrel removed. Connect the rivet to the AOA sensor with Tygon tubing. The sensor will compare the pressure differential between the pitot tube and the AOA port (pop rivet). Vans Aircraft uses this rivet probe in the latest version (iS) of their RV-12. The picture shows where I located the AOA rivet port in my wing. I drilled the rivet hole at the point where the 30 degree line is tangent to the wing. Although Van's tested different locations and determined that the optimum location is slightly farther down and and aft. Exactly where, I do not know. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479309#479309 Attachments: http://forums.matronics.com//files/angle_167.gif ________________________________ Message 7 _____________________________________ Time: 07:24:08 AM PST US From: FLYaDIVE Subject: Re: AeroElectric-List: Re: Diy AOA, anyone ? Joe: Guessing: But, probably 3 hole diameters behind the high point (Max profile) of the wings profile. Three diameters is a negative pressure point in open end resonance. Barry Although Van's tested different locations and determined that the optimum > location is slightly farther down and and aft. Exactly where, I do not > know. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=479309#479309 > > > Attachments: > > http://forums.matronics.com//files/angle_167.gif > > ________________________________ Message 8 _____________________________________ Time: 07:45:23 AM PST US From: Alec Myers Subject: Re: AeroElectric-List: Re: Diy AOA, anyone ? How is =9Coptimum=9D determined? You would have to calibrate for different airspeed and AoAs and creative som e kind of algorithm or lookup table, regardless of location, no? On Apr 13, 2018, at 10:23, FLYaDIVE wrote: Joe: Guessing: But, probably 3 hole diameters behind the high point (Max profile ) of the wings profile. Three diameters is a negative pressure point in ope n end resonance. Barry > Although Van's tested different locations and determined that the optimum location is slightly farther down and and aft. Exactly where, I do not kno w. > > -------- > Joe Gores > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=479309#479309 > > > > > Attachments: > > http://forums.matronics.com//files/angle_167.gif > > > > ========================= > - > Electric-List" rel="noreferrer" target="_blank">http://www.matronics.c om/Navigator?AeroElectric-List > ========================= > FORUMS - > eferrer" target="_blank">http://forums.matronics.com > ========================= > WIKI - > errer" target="_blank">http://wiki.matronics.com > ========================= > b Site - > -Matt Dralle, List Admin. > rel="noreferrer" target="_blank">http://www.matronics.com/contribution > ========================= > > > ________________________________ Message 9 _____________________________________ Time: 08:34:15 AM PST US From: Bob Verwey Subject: Re: AeroElectric-List: Re: Diy AOA, anyone ? Hey Joe, Thanks for providing a KISS solution for a change! No disrespect intended to any lister, but sometimes it seems (to this neophyte anyway) that the more complicated the solution, the better it is deemed? Best... Bob Verwey 082 331 2727 On 13 April 2018 at 16:10, user9253 wrote: > > An AOA probe can be made using only a single pop rivet with the mandrel > removed. Connect the rivet to the AOA sensor with Tygon tubing. The > sensor will compare the pressure differential between the pitot tube and > the AOA port (pop rivet). Vans Aircraft uses this rivet probe in the > latest version (iS) of their RV-12. The picture shows where I located the > AOA rivet port in my wing. I drilled the rivet hole at the point where the > 30 degree line is tangent to the wing. Although Van's tested different > locations and determined that the optimum location is slightly farther down > and and aft. Exactly where, I do not know. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=479309#479309 > > > Attachments: > > http://forums.matronics.com//files/angle_167.gif > > ________________________________ Message 10 ____________________________________ Time: 12:19:15 PM PST US Subject: AeroElectric-List: Re: Diy AOA, anyone ? From: "user9253" Here is a link to the VansAirforce thread about AOA in the RV-12. http://www.vansairforce.com/community/showthread.php?t=34040 I do not know where is the optimum point to measure air pressure. All I know is that I looked at the angle on Dynon's AOA probe and thought that 30 degrees looked about right. I drilled a hole and hooked up some tubing and it worked. Several other RV-12 builders followed my lead and they are all happy. When Van's came out with a new and improved version of the RV-12, they used my idea. But they did flight testing to determine the best location for the AOA port. The AOA needs to be calibrated during flight by performing a series of stalls, with and without flaps. AOA is displayed on the EFIS screen. There is also an audio indication that starts out as tone pulses. As stall approaches, the tone pulses get closer and closer together until at stall, there is one solid tone. A stall can occur at any airspeed depending on wing loading. A heavily load aircraft in a steep turn will stall at a much higher airspeed then when the plane is lightly loaded and flying straight. That is why many planes have stalled and crashed while in a traffic pattern. The pilot keeps the airspeed where he normally does, not taking into consideration the higher wing loading in a steep turn. A wing will always stall at the same AOA, regardless of wing loading. Now that I have AOA, I use that instead of airspeed. The FAA should mandate AOA and eliminate the requirement for airspeed indicators. OK, I am ready to be flamed. LOL For aircraft without an EFIS, a Dwyer Minihelic II 2-5002 Differential Pressure Gauge, Range 0-2.0"WC might work for a display, although I have never tried it. I would also add an audio pulsing tone. To andymeyer, I think the pressure differential for AOA is about 2" of water. 0.57psi converts to 15.7 inches of water. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479319#479319 ________________________________ Message 11 ____________________________________ Time: 02:19:13 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: Re: Diy AOA, anyone ? i use the airspeed indicator as an AoA indicator - you just have to mentally adjust the scale for weight and load factor. A bit like those airspeed indicators that have a sliding scale for true airspeed. My airspeed indicator has a sliding scale (in my head) for AoA. On Apr 13, 2018, at 15:18, user9253 wrote: Here is a link to the VansAirforce thread about AOA in the RV-12. http://www.vansairforce.com/community/showthread.php?t=34040 I do not know where is the optimum point to measure air pressure. All I know is that I looked at the angle on Dynon's AOA probe and thought that 30 degrees looked about right. I drilled a hole and hooked up some tubing and it worked. Several other RV-12 builders followed my lead and they are all happy. When Van's came out with a new and improved version of the RV-12, they used my idea. But they did flight testing to determine the best location for the AOA port. The AOA needs to be calibrated during flight by performing a series of stalls, with and without flaps. AOA is displayed on the EFIS screen. There is also an audio indication that starts out as tone pulses. As stall approaches, the tone pulses get closer and closer together until at stall, there is one solid tone. A stall can occur at any airspeed depending on wing loading. A heavily load aircraft in a steep turn will stall at a much higher airspeed then when the plane is lightly loaded and flying straight. That is why many planes have stalled and crashed while in a traffic pattern. The pilot keeps the airspeed where he normally does, not taking into consideration the higher wing loading in a steep turn. A wing will always stall at the same AOA, regardless of wing loading. Now that I have AOA, I use that instead of airspeed. The FAA should mandate AOA and eliminate the requirement for airspeed indicators. OK, I am ready to be flamed. LOL For aircraft without an EFIS, a Dwyer Minihelic II 2-5002 Differential Pressure Gauge, Range 0-2.0"WC might work for a display, although I have never tried it. I would also add an audio pulsing tone. To andymeyer, I think the pressure differential for AOA is about 2" of water. 0.57psi converts to 15.7 inches of water. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479319#479319 ________________________________ Message 12 ____________________________________ Time: 04:02:43 PM PST US From: Richard Girard Subject: Re: AeroElectric-List: Re: Diy AOA, anyone ? Here's an article one of the members of EAA Chapter 88 wrote for our newsletter a few years ago. Seems to be the same idea y'all are talking about. Rick Girard On Fri, Apr 13, 2018 at 4:18 PM, Alec Myers wrote: > > i use the airspeed indicator as an AoA indicator - you just have to > mentally adjust the scale for weight and load factor. A bit like those > airspeed indicators that have a sliding scale for true airspeed. My > airspeed indicator has a sliding scale (in my head) for AoA. > > On Apr 13, 2018, at 15:18, user9253 wrote: > > > Here is a link to the VansAirforce thread about AOA in the RV-12. > http://www.vansairforce.com/community/showthread.php?t=34040 > I do not know where is the optimum point to measure air pressure. All I > know is that I looked at the angle on Dynon's AOA probe and thought that 30 > degrees looked about right. I drilled a hole and hooked up some tubing a nd > it worked. Several other RV-12 builders followed my lead and they are al l > happy. When Van's came out with a new and improved version of the RV-12, > they used my idea. But they did flight testing to determine the best > location for the AOA port. > The AOA needs to be calibrated during flight by performing a series of > stalls, with and without flaps. AOA is displayed on the EFIS screen. > There is also an audio indication that starts out as tone pulses. As sta ll > approaches, the tone pulses get closer and closer together until at stall , > there is one solid tone. > A stall can occur at any airspeed depending on wing loading. A heavily > load aircraft in a steep turn will stall at a much higher airspeed then > when the plane is lightly loaded and flying straight. That is why many > planes have stalled and crashed while in a traffic pattern. The pilot > keeps the airspeed where he normally does, not taking into consideration > the higher wing loading in a steep turn. A wing will always stall at the > same AOA, regardless of wing loading. Now that I have AOA, I use that > instead of airspeed. The FAA should mandate AOA and eliminate the > requirement for airspeed indicators. > OK, I am ready to be flamed. LOL > For aircraft without an EFIS, a Dwyer Minihelic II 2-5002 Differential > Pressure Gauge, Range 0-2.0"WC might work for a display, although I have > never tried it. I would also add an audio pulsing tone. > To andymeyer, I think the pressure differential for AOA is about 2" of > water. 0.57psi converts to 15.7 inches of water. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=479319#479319 > > =========== =========== =========== =========== =========== > > -- =9CBlessed are the cracked, for they shall let in the light.=9D Groucho Marx ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-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/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-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.