---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 12/04/06: 28 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:14 AM - Re: Pitot Current Draw (Chuck Jensen) 2. 04:38 AM - Re: Pitot Current Draw (OldBob Siegfried) 3. 05:15 AM - Belly Com Antenna Shadowing (Snow, Daniel A.) 4. 06:11 AM - Re: Belly Com Antenna Shadowing (N777TY) 5. 06:27 AM - Re: Pitot Current Draw (Ernest Christley) 6. 06:44 AM - Re: Belly Com Antenna Shadowing (Michael T. Ice) 7. 06:47 AM - Re: Pitot Current Draw (Bruce Gray) 8. 07:32 AM - Re: Pitot Current Draw (Bret Smith) 9. 09:10 AM - Re: VOR antenna splitter? (steveadams) 10. 09:51 AM - Re: Pitot Current Draw (Ernest Christley) 11. 10:12 AM - Re: Belly Com Antenna Shadowing (Bill Boyd) 12. 10:43 AM - Re: Re: VOR antenna splitter? (John Erickson) 13. 11:11 AM - Instrument mounting screw washers (Mark Banus) 14. 11:20 AM - Re: Super-Battery pedigree? (Ed) 15. 12:05 PM - Re: Super-Battery pedigree? (Terry Watson) 16. 12:06 PM - Re: Pitot Current Draw (Chuck Jensen) 17. 12:25 PM - Re: Instrument mounting screw washers (Bruce Gray) 18. 12:30 PM - Re: Pitot Current Draw (Chuck Jensen) 19. 12:46 PM - Pitot heater solder (John Tvedte) 20. 12:54 PM - Re: Instrument mounting screw washers (Mark Banus) 21. 01:41 PM - Re: Super-Battery pedigree? (Rob Housman) 22. 02:25 PM - Re: Questions?? (Cleones) 23. 03:18 PM - Re: Re: Instrument mounting screw washers (Bruce Gray) 24. 03:19 PM - Re: Re: Instrument mounting screw washers (Bruce Gray) 25. 03:50 PM - Re: Pitot Current Draw (OldBob Siegfried) 26. 06:42 PM - Re: Pitot Current Draw (G McNutt) 27. 07:18 PM - Re: Pitot Current Draw/Static Ports (G McNutt) 28. 07:36 PM - Re: Pitot Current Draw (Keith Hallsten) ________________________________ Message 1 _____________________________________ Time: 04:14:04 AM PST US Subject: RE: AeroElectric-List: Pitot Current Draw From: "Chuck Jensen" Okay, I appreciate everyone holding forth that it's stupid to fly in ice....I'm not that dumb, I only look it. However, the question stands, how does one knock down the heat and current draw. Richard mentioned a 'strut switch'....whoever that is. Can someone enlighten us non-electrical types. What I'm concerned about is being in the clouds, close to freezing and loose electrical--I'd just as soon not have to turn off the pitot heat because it's sucking the battery dry in short order; I'd rather it be in long order. Chuck Jensen -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Sunday, December 03, 2006 11:31 PM Subject: Re: AeroElectric-List: Pitot Current Draw --> At 04:13 PM 12/3/2006 -0500, you wrote: >--> > >I have a pitot on an Exp. Aircraft that was designed for a heavier >aircraft. To accommodate the high speed and high altitude cold, the >pitot was configured to get very hot, with consumate amperage demand. >Given the lower demands of a GA aircraft, is there any way of reducing >the heating of the pitot (very warm to the touch would be fine...I >don't need to be able to brand someone!) with a consumate reduction in >amperage demand? Altitude and speed have little to do with a pitot tube's need to transfer heat to the surface. The kind of ice that a pitot tube is expected to handle happens at lower altitudes and relatively slow speeds. It's the super-cooled water droplets that freeze instantly on contact that represent the largest challenge to the pitot tube's ability to shed ice. If you've ever witnessed an ice-tunnel test on a piece of aviation de-ice equipment, you'd realize that if your pitot tube is being seriously challenged, then knowing altitude and airspeed are probably the least of your concerns. Icing conditions you're likely to survive can probably be shed by a relatively whimpy pitot tube deice heater but these are exceedingly difficult things to quantify. Pitot tubes we THOUGHT were adequate 30 years ago are scoffed at today. Intuitively, your assertion is not in error, ANY amount of heat will shed SOME ice. SOME ice is survivable while OTHER ice is not. Given the changes in de-ice certification protocols over the years, it becomes difficult to put numbers on "any", "some" and "other". So difficult that for anyone to offer you advice advocating "this many watts as opposed to that many watts" may be blowing smoke you-know-where. When that stuff starts appearing anywhere on your airplane is not the time to be experimenting with the adequacy of your pitot heater decisions. The best rule of thumb is put on the biggest heater you can find/afford but plan on the expeditious 180 no matter how robust you belive your heater to be. Bob . . . ________________________________ Message 2 _____________________________________ Time: 04:38:22 AM PST US From: OldBob Siegfried Subject: RE: AeroElectric-List: Pitot Current Draw Good Morning Chuck, Believe 'twas I who mentioned a strut switch. In any case it is switch mounted on a landing gear strut that switches something on or off when the aircraft is airborne. Such a switch is often used to prevent gear retraction when the aircraft is on the ground. It is not at all uncommon to have a strut switch on a nose gear that will actuate a relay which controls multiple functions when the aircraft is airborne. The dual heat pitot tube has often been activated by a nose gear strut switch on airplanes I have flown. I have never seen a pilot activated switch that handled that function, but I see no reason why one could not be installed if that is your desire. You could even have multiple heat choices if you wanted the added complication. Happy Skies, Old Bob --- Chuck Jensen wrote: > Jensen" > > Okay, I appreciate everyone holding forth that it's > stupid to fly in > ice....I'm not that dumb, I only look it. However, > the question stands, > how does one knock down the heat and current draw. > Richard mentioned a > 'strut switch'....whoever that is. Can someone > enlighten us > non-electrical types. What I'm concerned about is > being in the clouds, > close to freezing and loose electrical--I'd just as > soon not have to > turn off the pitot heat because it's sucking the > battery dry in short > order; I'd rather it be in long order. > > Chuck Jensen > > > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] > On Behalf Of > Robert L. Nuckolls, III > Sent: Sunday, December 03, 2006 11:31 PM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Pitot Current Draw > > > Nuckolls, III" > --> > > At 04:13 PM 12/3/2006 -0500, you wrote: > > Jensen" > >--> > > > >I have a pitot on an Exp. Aircraft that was > designed for a heavier > >aircraft. To accommodate the high speed and high > altitude cold, the > >pitot was configured to get very hot, with > consumate amperage demand. > >Given the lower demands of a GA aircraft, is there > any way of reducing > >the heating of the pitot (very warm to the touch > would be fine...I > >don't need to be able to brand someone!) with a > consumate reduction in > >amperage demand? > > Altitude and speed have little to do with a pitot > tube's > need to transfer heat to the surface. The kind of > ice that > a pitot tube is expected to handle happens at > lower altitudes > and relatively slow speeds. It's the super-cooled > water droplets > that freeze instantly on contact that represent > the largest > challenge to the pitot tube's ability to shed > ice. > > If you've ever witnessed an ice-tunnel test on a > piece > of aviation de-ice equipment, you'd realize that > if your > pitot tube is being seriously challenged, then > knowing > altitude and airspeed are probably the least of > your concerns. > > Icing conditions you're likely to survive can > probably be > shed by a relatively whimpy pitot tube deice > heater but these > are exceedingly difficult things to quantify. > Pitot tubes > we THOUGHT were adequate 30 years ago are scoffed > at today. > > Intuitively, your assertion is not in error, ANY > amount of > heat will shed SOME ice. SOME ice is survivable > while OTHER > ice is not. Given the changes in de-ice > certification protocols > over the years, it becomes difficult to put > numbers on "any", > "some" and "other". So difficult that for anyone > to offer you > advice advocating "this many watts as opposed to > that many > watts" may be blowing smoke you-know-where. > > When that stuff starts appearing anywhere on your > airplane > is not the time to be experimenting with the > adequacy of > your pitot heater decisions. The best rule of > thumb is put > on the biggest heater you can find/afford but > plan on the > expeditious 180 no matter how robust you belive > your heater > to be. > > Bob . . . > > > > > > > > > Click on > about > provided > www.buildersbooks.com > Admin. > > browse > Subscriptions page, > FAQ, > http://www.matronics.com/Navigator?AeroElectric-List > > > > > ________________________________ Message 3 _____________________________________ Time: 05:15:04 AM PST US Subject: AeroElectric-List: Belly Com Antenna Shadowing From: "Snow, Daniel A." I'm getting ready to mount my bent-whip com antenna on the belly of my RV-9A (tricycle gear). I would like to mount it near the main landing gear weldment forward of the spar where the bottom skin is thicker and where I can easily reach the BNC connector during flight. Can anyone give me an idea how much shadowing will occur from the gear leg? Thanks Daniel Snow RV-9A, Electrical ________________________________ Message 4 _____________________________________ Time: 06:11:34 AM PST US Subject: AeroElectric-List: Re: Belly Com Antenna Shadowing From: "N777TY" It works fine in that location. -------- RV-7A N777TY (res) Read this topic online here: http://forums.matronics.com/viewtopic.php?p=79001#79001 ________________________________ Message 5 _____________________________________ Time: 06:27:36 AM PST US From: Ernest Christley Subject: Re: AeroElectric-List: Pitot Current Draw Robert Sultzbach wrote: > >Hi Bob, > > Staying out of icing if possible is good advice. I >lost pitot static instruments 2 or 3 times in a full >deicing equipped Navy jet over a 3 year period. > I've been following this thread, and this post begs the question I've been mulling over. What good is a heated pitot in an airplane without deicing equipment? I'm thinking that if the pitot is covered in ice, then so is the rest of the plane. Your airspeed is now next to useless, because all those stall speed numbers are now meaningless. Whatever they were before, they changed when the ice modified all the airfoils and the CG. A cockpit referenced backup altimeter would seem to give the best bang for the $time$...not terribly accurate, but sufficient to keep you out of cumulous granite until you can improve your situation. Ernest (a sunny day flyer). -- ,|"|"|, Ernest Christley | ----===<{{(oQo)}}>===---- Dyke Delta Builder | o| d |o http://ernest.isa-geek.org | ________________________________ Message 6 _____________________________________ Time: 06:44:29 AM PST US From: "Michael T. Ice" Subject: Re: AeroElectric-List: Belly Com Antenna Shadowing Daniel, I just ordered a bent whip antenna to mount on the belly of the RV-9 I am building. I am considering mounting it on the other side of the fuselage so that the co-pilot can reach it. Why? I thought that if I ever have a radio failure and have to switch to hand held then I will just ask the co-pilot to hook up the radio rather than me doing it while trying to fly and navigate. If I don't have a co-pilot at that moment then I guess I will get to practice my "lost comm." procedures. I remember during my initial flight training many years ago my instructor would yank the microphone out of my hand and tell me, "The Wright brothers invented the airplane not Marconi, FLY the Plane". Mike Ice RV-9, Electrical ----- Original Message ----- From: "Snow, Daniel A." Sent: Monday, December 04, 2006 4:13 AM Subject: AeroElectric-List: Belly Com Antenna Shadowing > > > I'm getting ready to mount my bent-whip com antenna on the belly of my > RV-9A (tricycle gear). I would like to mount it near the main landing > gear weldment forward of the spar where the bottom skin is thicker and > where I can easily reach the BNC connector during flight. Can anyone > give me an idea how much shadowing will occur from the gear leg? > > Thanks > > Daniel Snow > RV-9A, Electrical > > > ________________________________ Message 7 _____________________________________ Time: 06:47:58 AM PST US From: "Bruce Gray" Subject: RE: AeroElectric-List: Pitot Current Draw Didn't your CFII tell you to break the glass on the VSI if that happens. But your altimeter wouldn't be effected by a pitot blockage. We all have heated static ports, right? Alternate static air valves? Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ernest Christley Sent: Monday, December 04, 2006 9:27 AM Subject: Re: AeroElectric-List: Pitot Current Draw Robert Sultzbach wrote: > >Hi Bob, > > Staying out of icing if possible is good advice. I >lost pitot static instruments 2 or 3 times in a full >deicing equipped Navy jet over a 3 year period. > I've been following this thread, and this post begs the question I've been mulling over. What good is a heated pitot in an airplane without deicing equipment? I'm thinking that if the pitot is covered in ice, then so is the rest of the plane. Your airspeed is now next to useless, because all those stall speed numbers are now meaningless. Whatever they were before, they changed when the ice modified all the airfoils and the CG. A cockpit referenced backup altimeter would seem to give the best bang for the $time$...not terribly accurate, but sufficient to keep you out of cumulous granite until you can improve your situation. Ernest (a sunny day flyer). -- ,|"|"|, Ernest Christley | ----===<{{(oQo)}}>===---- Dyke Delta Builder | o| d |o http://ernest.isa-geek.org | ________________________________ Message 8 _____________________________________ Time: 07:32:58 AM PST US From: "Bret Smith" Subject: Re: AeroElectric-List: Pitot Current Draw Chuck, Thank you for addressing this scenario. I, too, would like to hear others respond. As for me, icing or not, if I lose my main alternator, I would switch on Endurance mode (which is only 8 amps...thus, no pitot) and land that puppy ASAP. This is not an emergent situation. Not so with your stock Cessna. A well designed electrical system can make a huge difference in the outcome of a flight. Bret Smith ----- Original Message ----- From: "Chuck Jensen" Sent: Monday, December 04, 2006 7:13 AM Subject: RE: AeroElectric-List: Pitot Current Draw > > > Okay, I appreciate everyone holding forth that it's stupid to fly in > ice....I'm not that dumb, I only look it. However, the question stands, > how does one knock down the heat and current draw. Richard mentioned a > 'strut switch'....whoever that is. Can someone enlighten us > non-electrical types. What I'm concerned about is being in the clouds, > close to freezing and loose electrical--I'd just as soon not have to > turn off the pitot heat because it's sucking the battery dry in short > order; I'd rather it be in long order. > > Chuck Jensen > > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > Robert L. Nuckolls, III > Sent: Sunday, December 03, 2006 11:31 PM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Pitot Current Draw > > > --> > > At 04:13 PM 12/3/2006 -0500, you wrote: > >>--> >> >>I have a pitot on an Exp. Aircraft that was designed for a heavier >>aircraft. To accommodate the high speed and high altitude cold, the >>pitot was configured to get very hot, with consumate amperage demand. >>Given the lower demands of a GA aircraft, is there any way of reducing >>the heating of the pitot (very warm to the touch would be fine...I >>don't need to be able to brand someone!) with a consumate reduction in >>amperage demand? > > Altitude and speed have little to do with a pitot tube's > need to transfer heat to the surface. The kind of ice that > a pitot tube is expected to handle happens at lower altitudes > and relatively slow speeds. It's the super-cooled water droplets > that freeze instantly on contact that represent the largest > challenge to the pitot tube's ability to shed ice. > > If you've ever witnessed an ice-tunnel test on a piece > of aviation de-ice equipment, you'd realize that if your > pitot tube is being seriously challenged, then knowing > altitude and airspeed are probably the least of your concerns. > > Icing conditions you're likely to survive can probably be > shed by a relatively whimpy pitot tube deice heater but these > are exceedingly difficult things to quantify. Pitot tubes > we THOUGHT were adequate 30 years ago are scoffed at today. > > Intuitively, your assertion is not in error, ANY amount of > heat will shed SOME ice. SOME ice is survivable while OTHER > ice is not. Given the changes in de-ice certification protocols > over the years, it becomes difficult to put numbers on "any", > "some" and "other". So difficult that for anyone to offer you > advice advocating "this many watts as opposed to that many > watts" may be blowing smoke you-know-where. > > When that stuff starts appearing anywhere on your airplane > is not the time to be experimenting with the adequacy of > your pitot heater decisions. The best rule of thumb is put > on the biggest heater you can find/afford but plan on the > expeditious 180 no matter how robust you belive your heater > to be. > > Bob . . . > > > ________________________________ Message 9 _____________________________________ Time: 09:10:20 AM PST US Subject: AeroElectric-List: Re: VOR antenna splitter? From: "steveadams" I have the same setup, GNS430 and SL30. I attached a BNC T-connector directly to the VOR/GS input connection on the splitter. Connected VOR/GS antenna cable to 1 branch of the T, and ran a short cable to the SL30 from the other branch of the T. That way, SL30 gets both VOR and GS, while the 430 gets the split outputs from the splitter. I don't know how much signal loss I have, but it has worked well for almost 2 years. The SL30 does pick up the glideslope a bit sooner than the 430. I haven't noticed a consistent difference in VOR range between the two. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=79066#79066 ________________________________ Message 10 ____________________________________ Time: 09:51:20 AM PST US From: Ernest Christley Subject: Re: AeroElectric-List: Pitot Current Draw Bruce Gray wrote: > >Didn't your CFII tell you to break the glass on the VSI if that happens. But >your altimeter wouldn't be effected by a pitot blockage. We all have heated >static ports, right? Alternate static air valves? > >Bruce >www.glasair.org > > > > Hard to do without a mechanical VSI 8*) Breaking the glass on your EFIS is just not pretty. If I did have a mechanical VSI, I still wouldn't break the glass on it. Just no point in going around busting up perfectly good instruments. I assume that if ice is building up to block the pitot, the static is very close to being next in line. Then you have to be aware enough to notice that something is sneaking up on you. I've never had it happen, but what I understand is that the meter slowly becomes more and more innacurate. It doesn't just fall over dead. A backup device feeding from a safe alternate source (like cabin air), will give you a much quicker heads up. That might be a good feature to have on an EFIS. Compare the cabin to static pressures and raise an alarm if they get out of range...then display both 'altitudes' if the pilot chooses. -- ,|"|"|, Ernest Christley | ----===<{{(oQo)}}>===---- Dyke Delta Builder | o| d |o http://ernest.isa-geek.org | ________________________________ Message 11 ____________________________________ Time: 10:12:57 AM PST US From: "Bill Boyd" Subject: Re: AeroElectric-List: Belly Com Antenna Shadowing Why not run coax to a bulkhead jack on the panel so either one of you can reach it with a patch cord from the handheld? Regarding antenna location, I doubt you'll notice shadowing from the gear legs. I have done my RV-6A this way and it's not an operational issue. I abandoned wingtip antennas due to shadowing and a subsequent turtledeck location due to severe RF in the cockpit (headphones) due to _lack of_ shadowing. I could not ameliorate that problem with ferrites on the headset cabling, so I gave up and moved the comm whip to the belly between the gear legs where it apparently belongs ;-). You will likely experience front-end overload when close to another transmitter- signals will sound garbled- but that's not shadowing and should not depend much on antenna location anyway. Best, -Stormy On 12/4/06, Michael T. Ice wrote: > > Daniel, > > I just ordered a bent whip antenna to mount on the belly of the RV-9 I am > building. I am considering mounting it on the other side of the fuselage so > that the co-pilot can reach it. Why? I thought that if I ever have a radio > failure and have to switch to hand held then I will just ask the co-pilot to > hook up the radio rather than me doing it while trying to fly and navigate. > If I don't have a co-pilot at that moment then I guess I will get to > practice my "lost comm." procedures. I remember during my initial flight > training many years ago my instructor would yank the microphone out of my > hand and tell me, "The Wright brothers invented the airplane not Marconi, > FLY the Plane". > > Mike Ice > RV-9, Electrical > > ----- Original Message ----- > From: "Snow, Daniel A." > To: > Sent: Monday, December 04, 2006 4:13 AM > Subject: AeroElectric-List: Belly Com Antenna Shadowing > > > > > > > > I'm getting ready to mount my bent-whip com antenna on the belly of my > > RV-9A (tricycle gear). I would like to mount it near the main landing > > gear weldment forward of the spar where the bottom skin is thicker and > > where I can easily reach the BNC connector during flight. Can anyone > > give me an idea how much shadowing will occur from the gear leg? > > > > Thanks > > > > Daniel Snow > > RV-9A, Electrical > > > > > > > > > > > > > > ________________________________ Message 12 ____________________________________ Time: 10:43:54 AM PST US From: "John Erickson" Subject: RE: AeroElectric-List: Re: VOR antenna splitter? LOL, it's always the simple solutions that evade me... Thanks much... John -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of steveadams Sent: Monday, December 04, 2006 10:09 AM Subject: AeroElectric-List: Re: VOR antenna splitter? --> I have the same setup, GNS430 and SL30. I attached a BNC T-connector directly to the VOR/GS input connection on the splitter. Connected VOR/GS antenna cable to 1 branch of the T, and ran a short cable to the SL30 from the other branch of the T. That way, SL30 gets both VOR and GS, while the 430 gets the split outputs from the splitter. I don't know how much signal loss I have, but it has worked well for almost 2 years. The SL30 does pick up the glideslope a bit sooner than the 430. I haven't noticed a consistent difference in VOR range between the two. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=79066#79066 __________ NOD32 1899 (20061204) Information __________ ________________________________ Message 13 ____________________________________ Time: 11:11:59 AM PST US From: "Mark Banus" Subject: AeroElectric-List: Instrument mounting screw washers Awhile back someone mentioned here or on the Glasair.org BB that model railroad wheel washers were ideal size for the instrument mounting screws. I can't find the message. I tried the model railroad show in VA Beach this weekend to no avail. Anyone have a line on where to get these critters? Mark Banus Glasair II ________________________________ Message 14 ____________________________________ Time: 11:20:36 AM PST US From: Ed Subject: Re: AeroElectric-List: Super-Battery pedigree? I seem to recall that some Mazda Miata's (not all) had a special battery with an ~10 year life span. Maybe follow that lead. Ed Mueller N3730G RV10 in Progress Robert L. Nuckolls, III wrote: > > > At 12:33 PM 11/30/2006 -0500, you wrote: > >> Hi Bob, >> >> Got your email from a builder friend of mine. I guess you are an >> electrics expert, so perhaps you can answer my battery questions. >> >> I fly a Glasair I RG that I finished in 1988. In 1986, when I began >> to work on the retractable gear, I bought a 12 volt sealed battery >> from a company in Scottsdale, AZ called Electromarketing. I found >> them in Sport Aviation. >> >> Long story short, that battery is still ticking in my Glasair. About >> 3 years ago in the winter, it didn't have quite enough umph to start, >> so I put a trickle charger on it that came with the battery. It was >> so old, that the polarity had fallen off. I figured 50-50 chance and >> left it overnight charging. The next day the battery was stone dead. >> It wouldn't close the relay. I figured my magic battery was finally >> dead. However, I extracted it from the battery box in the tail and >> brought it home and put a different charger on it. Back to life she >> came. I had not opened that battery box in over 15 years. >> >> Have you ever heard of a battery lasting this long? >> >> Do you know what happened to that company? I'd like to buy another >> battery from them if the need ever arises. >> >> I still have the receipt from that company, but have been unable to >> find them. I asked EAA about it years ago, but never got a response. > > I'm sorry, I'm not familiar with that company. > They are probably a distributor and not a manufacturer. > I'm not aware of anyone having the success you've > experienced. When that battery finally becomes unserviceable > in your airplane, you might consider shipping it to > me. I'll see if I can identify the source. > > Bob . . . > > > --------------------------------------------------------- > < What is so wonderful about scientific truth...is that > > < the authority which determines whether there can be > > < debate or not does not reside in some fraternity of > > < scientists; nor is it divine. The authority rests > > < with experiment. > > < --Lawrence M. Krauss > > --------------------------------------------------------- > > ________________________________ Message 15 ____________________________________ Time: 12:05:09 PM PST US From: "Terry Watson" Subject: RE: AeroElectric-List: Super-Battery pedigree? They have a special battery alright. It mounts in the trunk and has two small tubes to vent gases to the outside, but I sure haven't been getting 10 years out of them, but maybe there is a special one that I don't know about. There is at least one after market battery available for the Miata, but I usually go to the dealer and pay the Big Price (around $100). Terry Rv-8A in progress '92 Miata since '95 I seem to recall that some Mazda Miata's (not all) had a special battery with an ~10 year life span. Maybe follow that lead. Ed Mueller N3730G RV10 in Progress ________________________________ Message 16 ____________________________________ Time: 12:06:46 PM PST US Subject: RE: AeroElectric-List: Pitot Current Draw From: "Chuck Jensen" Wow, I must be hard-of-speaking (or writing). I concede that flying into icing when not so equipped is not a good idea, but if a person flies IFR in the winter most anywhere in the continental US, sooner or later, they'll pick up some ice. Even if my wings start looking like something that should be used to cool a gin and tonic, I don't want to lose air speed indication. Granted, I may not know what my new stall speed is, but I would like to know WHAT my speed is...and I can't do that with a pitot full of ice. So, the question on the table is still the same, is there a way off 'turning down the heat' and reducing current draw? Chuck Jensen -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ernest Christley Sent: Monday, December 04, 2006 9:27 AM Subject: Re: AeroElectric-List: Pitot Current Draw --> Robert Sultzbach wrote: >--> > >Hi Bob, > > Staying out of icing if possible is good advice. I >lost pitot static instruments 2 or 3 times in a full >deicing equipped Navy jet over a 3 year period. > I've been following this thread, and this post begs the question I've been mulling over. What good is a heated pitot in an airplane without deicing equipment? I'm thinking that if the pitot is covered in ice, then so is the rest of the plane. Your airspeed is now next to useless, because all those stall speed numbers are now meaningless. Whatever they were before, they changed when the ice modified all the airfoils and the CG. A cockpit referenced backup altimeter would seem to give the best bang for the $time$...not terribly accurate, but sufficient to keep you out of cumulous granite until you can improve your situation. Ernest (a sunny day flyer). -- ,|"|"|, Ernest Christley | ----===<{{(oQo)}}>===---- Dyke Delta Builder | o| d |o http://ernest.isa-geek.org | ________________________________ Message 17 ____________________________________ Time: 12:25:04 PM PST US From: "Bruce Gray" Subject: RE: AeroElectric-List: Instrument mounting screw washers Have you tried the aviation department at Home Depot? Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Mark Banus Sent: Monday, December 04, 2006 2:11 PM Subject: AeroElectric-List: Instrument mounting screw washers Awhile back someone mentioned here or on the Glasair.org BB that model railroad wheel washers were ideal size for the instrument mounting screws. I can't find the message. I tried the model railroad show in VA Beach this weekend to no avail. Anyone have a line on where to get these critters? Mark Banus Glasair II ________________________________ Message 18 ____________________________________ Time: 12:30:21 PM PST US Subject: RE: AeroElectric-List: Pitot Current Draw From: "Chuck Jensen" Old Bob, I reread your posting more carefully this time which leads me to a follow up question. Now that I understand what a 'strut switch' is (which I knew by a different name), I'm curious how the 'low heat' for the ground operations worked. In other words, how did it provide low heat on the ground and high heat in the air? Chuck Jensen -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of OldBob Siegfried Sent: Sunday, December 03, 2006 10:02 PM Subject: Re: AeroElectric-List: Pitot Current Draw --> Good Evening Lynn, Dick and Chuck, In a previous life, I flew quite a few airplanes that had a high and a low heat for the pitot tubes. They were on low for ground operations and on high heat for airborne use. I think it was controlled by a strut switch, but not sure. Worked well though. Happy Skies, Old Bob --- Lynn Riggs wrote: > I would like to add that the pitot tube should burn > your hand if you grab it after it has been on for > more than 1 or 2 minutes. > > "Richard E. Tasker" wrote: > Tasker" > > There are ways, but what leads you to believe that > the pitot is really > too hot? The whole purpose of the heater is to keep > it clear in any > condition - rain, freezing rain, cold ambient, etc. > Depending on what > plane you have, you will be flying at upwards of 200 > mph through all > this (hopefully NOT freezing rain) and the last > thing you want is for > the pitot to freeze up. > > Dick Tasker > > Chuck Jensen wrote: > > Jensen" > > > >I have a pitot on an Exp. Aircraft that was > designed for a heavier > >aircraft. To accommodate the high speed and high > altitude cold, the > >pitot was configured to get very hot, with > consumate amperage demand. > >Given the lower demands of a GA aircraft, is there > any way of reducing > >the heating of the pitot (very warm to the touch > would be fine...I don't > >need to be able to brand someone!) with a consumate > reduction in > >amperage demand? > > > >Chuck Jensen > > > > > > > > > > > > > > > > > > -- > Please Note: > No trees were destroyed in the sending of this > message. We do concede, however, > that a significant number of electrons may have been > temporarily inconvenienced. > -- > > > > > > > > > Lynn A. Riggs > riggs_la@yahoo.com > St. Paul, MN > BH #656 Kit #22 > http://home.comcast.net/~lariggs/wsb/html/view.cgi-home.html-.html > > --------------------------------- ________________________________ Message 19 ____________________________________ Time: 12:46:23 PM PST US Subject: AeroElectric-List: Pitot heater solder From: "John Tvedte" Ok - I'm installing an AN5812 Pitot heater... The installation instructions specify a QQ-S-571 lead-silver solder. The connectors do appear to be silver plated. Doing some searches for QQ-S-571 yielded some silver bearing solders in the 1.5% to 2.5% range. The QQ-S-561 is the spec for silver solder. I was wondering if a Sn62Pb36Ag02 alloy would do the trick. Thanks, John ________________________________ Message 20 ____________________________________ Time: 12:54:20 PM PST US From: "Mark Banus" Subject: AeroElectric-List: RE: Instrument mounting screw washers Bruce, That was my first stop. ________________________________ Message 21 ____________________________________ Time: 01:41:15 PM PST US From: "Rob Housman" Subject: RE: AeroElectric-List: Super-Battery pedigree? As the original owner of a '95 Miata I know that the original battery lasted just a bit longer than ten years, but I also know that here in SoCal the climate imposes no real demands on the battery so getting that "long" life probably says nothing about the battery. As far as I can tell (from the lack of standard size aftermarket batteries that will fit, a total of zero that I've found) this is a non-standard SIZE specified by Mazda to fit into a tight space and there is not anything special about the design. Aside from the size the only difference I can see is the outrageous price. Best regards, Rob Housman A070 Airframe complete Irvine, CA -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Ed Sent: Monday, December 04, 2006 11:19 AM Subject: Re: AeroElectric-List: Super-Battery pedigree? I seem to recall that some Mazda Miata's (not all) had a special battery with an ~10 year life span. Maybe follow that lead. Ed Mueller N3730G RV10 in Progress Robert L. Nuckolls, III wrote: > > > At 12:33 PM 11/30/2006 -0500, you wrote: > >> Hi Bob, >> >> Got your email from a builder friend of mine. I guess you are an >> electrics expert, so perhaps you can answer my battery questions. >> >> I fly a Glasair I RG that I finished in 1988. In 1986, when I began >> to work on the retractable gear, I bought a 12 volt sealed battery >> from a company in Scottsdale, AZ called Electromarketing. I found >> them in Sport Aviation. >> >> Long story short, that battery is still ticking in my Glasair. About >> 3 years ago in the winter, it didn't have quite enough umph to start, >> so I put a trickle charger on it that came with the battery. It was >> so old, that the polarity had fallen off. I figured 50-50 chance and >> left it overnight charging. The next day the battery was stone dead. >> It wouldn't close the relay. I figured my magic battery was finally >> dead. However, I extracted it from the battery box in the tail and >> brought it home and put a different charger on it. Back to life she >> came. I had not opened that battery box in over 15 years. >> >> Have you ever heard of a battery lasting this long? >> >> Do you know what happened to that company? I'd like to buy another >> battery from them if the need ever arises. >> >> I still have the receipt from that company, but have been unable to >> find them. I asked EAA about it years ago, but never got a response. > > I'm sorry, I'm not familiar with that company. > They are probably a distributor and not a manufacturer. > I'm not aware of anyone having the success you've > experienced. When that battery finally becomes unserviceable > in your airplane, you might consider shipping it to > me. I'll see if I can identify the source. > > Bob . . . > > > --------------------------------------------------------- > < What is so wonderful about scientific truth...is that > > < the authority which determines whether there can be > > < debate or not does not reside in some fraternity of > > < scientists; nor is it divine. The authority rests > > < with experiment. > > < --Lawrence M. Krauss > > --------------------------------------------------------- > > ________________________________ Message 22 ____________________________________ Time: 02:25:43 PM PST US From: Cleones Subject: Re: AeroElectric-List: Questions?? At 05:27 PM 12/2/2006, you wrote: > >Cleones wrote: > >> >>Hi Bob, In the John Deere alternator and regulator frequently >>talked about here is the rectifier in the regulator? > >Yes. > >> And, Is the alternator generating 3 phase AC ? > >No. It is single phase AC. There are only two wires coming out of it. > >>And, about what voltage is the output of the alternator. > >It will go up to about 200 volts open circuit but when loaded it >will be in the vicinity of 15 volts depending on how you measure it. > >> Also, since we know that the # 5 terminal must be connected to >> voltage or the alternator doesn't work. I have tried this and it >> is true. Then what is the circuit like? And would it be a good >> place to connect the overvoltage crowbar to? Enjoyed your >> lectures at Bloomington recently. Cleone > >I interupt the wires into the regulator. In the past Bob has said >that either into or out of the regulator will do the job but I >wanted to be able to cut power to the regulator in case it was >overheating or internally shorted. >The regulator uses the battery connection to turn itself on and to >sense the battery voltage so that it can regulate to 14.4 volts nominal output. > >Ken Ken, > Thanks. Let me consider this. So.. doesn't this indicate > using a NO relay? This circuit might be carring very high current > at the time the relay opened. Hopefully the contacts would not be > welded closed and the spinning alternator would not be delivering > current to the regulator and we would achieve the desired > results. I don't know if an attempt to fuse the AC output at a > little more than the rated current of the alternator is called for > or not. This might not be advisable because it might cause the > charging to be shut down unnecesarily. Do you agree with my > thoughts? Also regarding the # 5 connection of the regulator. I > started the engine and made sure the alternator was working with > the wire connected and then redid this with the wire off. The > first time the voltage was about 14 volts and the second time it > was just a little over 12. Thanks again. Cleone > > ________________________________ Message 23 ____________________________________ Time: 03:18:44 PM PST US From: "Bruce Gray" Subject: RE: AeroElectric-List: RE: Instrument mounting screw washers I took the easy way out and countersunk all my instrument mounting screw holes. (NOT) Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Mark Banus Sent: Monday, December 04, 2006 3:54 PM Subject: AeroElectric-List: RE: Instrument mounting screw washers Bruce, That was my first stop. ________________________________ Message 24 ____________________________________ Time: 03:19:33 PM PST US From: "Bruce Gray" Subject: RE: AeroElectric-List: RE: Instrument mounting screw washers I take it that what you're looking for is a flat washer with the same diameter as the screw head. Will you need #4, #6, and #8's? Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Mark Banus Sent: Monday, December 04, 2006 3:54 PM Subject: AeroElectric-List: RE: Instrument mounting screw washers Bruce, That was my first stop. ________________________________ Message 25 ____________________________________ Time: 03:50:55 PM PST US From: OldBob Siegfried Subject: RE: AeroElectric-List: Pitot Current Draw Good Evening Chuck, That I do not know much about, but I do recall one airplane where the low power was twenty eight volt DC and the high temperature used 115 volt, 400 cycle, AC. I would imagibne all of the varying power ones used some variaton of high and low voltages. Dropping resistors sure wouldn't solve your problem, but an electronically cycled DC voltage may work. Hopefully, 'Lectric Bob will have an idea! Happy Skies, Old Bob --- Chuck Jensen wrote: > Jensen" > > Old Bob, > > I reread your posting more carefully this time which > leads me to a > follow up question. Now that I understand what a > 'strut switch' is > (which I knew by a different name), I'm curious how > the 'low heat' for > the ground operations worked. In other words, how > did it provide low > heat on the ground and high heat in the air? > > Chuck Jensen > > > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] > On Behalf Of > OldBob Siegfried > Sent: Sunday, December 03, 2006 10:02 PM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Pitot Current Draw > > > Siegfried > --> > > Good Evening Lynn, Dick and Chuck, > > In a previous life, I flew quite a few airplanes > that > had a high and a low heat for the pitot tubes. They > were on low for ground operations and on high heat > for > airborne use. > > I think it was controlled by a strut switch, but not > sure. > > Worked well though. > > Happy Skies, > > Old Bob > --- Lynn Riggs wrote: > > > I would like to add that the pitot tube should > burn > > your hand if you grab it after it has been on for > > more than 1 or 2 minutes. > > > > "Richard E. Tasker" > wrote: > E. > > Tasker" > > > > There are ways, but what leads you to believe that > > the pitot is really > > too hot? The whole purpose of the heater is to > keep > > it clear in any > > condition - rain, freezing rain, cold ambient, > etc. > > Depending on what > > plane you have, you will be flying at upwards of > 200 > > mph through all > > this (hopefully NOT freezing rain) and the last > > thing you want is for > > the pitot to freeze up. > > > > Dick Tasker > > > > Chuck Jensen wrote: > > > > Jensen" > > > > > >I have a pitot on an Exp. Aircraft that was > > designed for a heavier > > >aircraft. To accommodate the high speed and high > > altitude cold, the > > >pitot was configured to get very hot, with > > consumate amperage demand. > > >Given the lower demands of a GA aircraft, is > there > > any way of reducing > > >the heating of the pitot (very warm to the touch > > would be fine...I don't > > >need to be able to brand someone!) with a > consumate > > reduction in > > >amperage demand? > > > > > >Chuck Jensen > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > Please Note: > > No trees were destroyed in the sending of this > > message. We do concede, however, > > that a significant number of electrons may have > been > > temporarily inconvenienced. > > -- > > > > > > > > > > > > > > > > > > Lynn A. Riggs > > riggs_la@yahoo.com > > St. Paul, MN > > BH #656 Kit #22 > > > http://home.comcast.net/~lariggs/wsb/html/view.cgi-home.html-.html > > > > --------------------------------- > > > > > > > > > > Click on > about > provided > www.buildersbooks.com > Admin. > > browse > Subscriptions page, > FAQ, > http://www.matronics.com/Navigator?AeroElectric-List > > > > > ________________________________ Message 26 ____________________________________ Time: 06:42:57 PM PST US From: G McNutt Subject: Re: AeroElectric-List: Pitot Current Draw Pitch reference - Yes, if you want to paint a gloomy picture lets throw in night time, snow showers, over water and your venturi icing up and the gyros slowing down, well with a heated pitot at least you could still fly needle ball and airspeed! Lost a friend who did not have pitot heat, you cannot fly with needle ball and altimeter. George in Langley BC > > I've been following this thread, and this post begs the question I've > been mulling over. > > What good is a heated pitot in an airplane without deicing equipment? > I'm thinking that if the pitot is covered in ice, then so is the rest > of the plane. Your airspeed is now next to useless, because all those > stall speed numbers are now meaningless. Whatever they were before, > they changed when the ice modified all the airfoils and the CG. A > cockpit referenced backup altimeter would seem to give the best bang > for the $time$...not terribly accurate, but sufficient to keep you out > of cumulous granite until you can improve your situation. > > Ernest (a sunny day flyer). > ________________________________ Message 27 ____________________________________ Time: 07:18:36 PM PST US From: G McNutt Subject: Re: AeroElectric-List: Pitot Current Draw/Static Ports Hi Bruce I know you said that with tongue in cheek, but it is interesting point. If I remember correctly an alternate static valve or heated ports are not required (Canada) if it can be demonstrated that the static ports are not susceptible to icing. I opted for alternate static valve on my RV's however I think that with dual static ports on the aft end of a tapering fuselage they would be immune to icing unless the aircraft was flown in a side slip. Anyone ever heard of side static ports icing over/up? George in Langley BC > > Bruce Gray wrote: > snip >> We all have heated >> static ports, right? Alternate static air valves? >> > ________________________________ Message 28 ____________________________________ Time: 07:36:36 PM PST US From: "Keith Hallsten" Subject: AeroElectric-List: RE: Pitot Current Draw Chuck, I mounted a 28v "Known Ice" pitot on the nose of my Velocity. Since I have a 14 volt electrical system, its power consumption will be reduced by a factor of 4 (power = V * V / R). I figure that is sufficient for my purposes, because a Velocity is NOT a "Known Ice" type of airframe. If I should find enough ice to overwhelm my "lightweight" pitot heating system, I have bigger problems than the pitot. I'm not flying yet, but that's my position for now. Actually, now that we all have GPS available to us, loss of pitot is not as critical as it used to be. With a fat margin to allow for wind, flying by groundspeed is generally a fair approximation. Regards, Keith Hallsten Subject: RE: Pitot Current Draw From: Chuck Jensen (cjensen@dts9000.com ) Date: Mon Dec 04 - 12:06 PM Wow, I must be hard-of-speaking (or writing). I concede that flying into icing when not so equipped is not a good idea, but if a person flies IFR in the winter most anywhere in the continental US, sooner or later, they'll pick up some ice. Even if my wings start looking like something that should be used to cool a gin and tonic, I don't want to lose air speed indication. Granted, I may not know what my new stall speed is, but I would like to know WHAT my speed is...and I can't do that with a pitot full of ice. So, the question on the table is still the same, is there a way off 'turning down the heat' and reducing current draw? Chuck Jensen ------------------------------------------------------------------------------------- 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.