---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 10/12/03: 18 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:28 AM - Re:Stick-shaker for stall warning (Carl Coulter) 2. 03:57 AM - Re: Re: Stick-shaker for stall warning (Neville Kilford) 3. 07:19 AM - Re: Re: Stick-shaker for stall warning (Jim Sower) 4. 08:01 AM - Re: Re:Stick-shaker for stall warning (Jim Sower) 5. 08:08 AM - Re: Stick-shaker for stall warning (Joel Harding) 6. 08:34 AM - Re: Stick-shaker for stall warning (Benford2@aol.com) 7. 09:03 AM - Re: Re: Stick-shaker for stall warning (Robert L. Nuckolls, III) 8. 09:07 AM - Re: Re: Stick-shaker for stall warning (Kevin Horton) 9. 09:31 AM - Re: Re: Stick-shaker for stall warning (Benford2@aol.com) 10. 09:39 AM - Re: Alternator Noise in Headset (Robert L. Nuckolls, III) 11. 09:56 AM - Stick Shakers (John Perry) 12. 09:58 AM - Re: Re: Stick-shaker for stall warning (caspainhower@aep.com) 13. 12:08 PM - Re: Re: Alternator Noise in Headset (Pete Waters) 14. 02:42 PM - Re: Re: Alternator Noise in Headset (Ernest Kells) 15. 04:07 PM - Re: Stick-shaker for stall warning (Scott, Ian) 16. 08:44 PM - Strobes and comm Ant (John Perry) 17. 09:00 PM - Re: Alternator Noise in Headset (Robert L. Nuckolls, III) 18. 09:29 PM - Grounding fuel flow sender (richard@riley.net) ________________________________ Message 1 _____________________________________ Time: 01:28:08 AM PST US From: Carl Coulter Subject: AeroElectric-List: RE:Stick-shaker for stall warning --> AeroElectric-List message posted by: Carl Coulter Motors? Eccentrics? We are electro-whizzies ;-) How about a ball bearing in a non-ferrous tube with a coil at each end? Drive the coils with a multivibrator ckt to rattle the ball back and forth. I'm afraid this isn't my brilliance. About 25 years ago I worked with a guy that had a patent to do this. He had gotten a job offer from an airplane outfit for a lot of money. He was certain the offer stemmed from them wanting his patent. I don't remember him describing it other than "rattling a steel ball with an electromagnet". Concept is simple - an Al tube with a coil in a plastic bobbin on each end - maybe a steel slug glued in the tube under each bobbin - appropriate sized ball bearing in the center. I don't know if his idea ever went anywhere. carl ***************************** Subject: AeroElectric-List: Stick-shaker for stall warning --> AeroElectric-List message posted by: "James Foerster" Friends, I'm building a 4 place Jabiru, and this has a central control stick. I am considering the addition of a stick-shaker as used by military and commercial planes. A model airplane motor, run at the "appropriate" speed and driving an eccentric weight should work. ________________________________ Message 2 _____________________________________ Time: 03:57:51 AM PST US From: "Neville Kilford" Subject: Re: AeroElectric-List: Re: Stick-shaker for stall warning --> AeroElectric-List message posted by: "Neville Kilford" Jim, How about Piper's elegant solution -- a large round light on the panel next to the airspeed indicator. It sounds facile to make such a trivial suggestion, but it works wonderfully well and couldn't be any less expensive to make. A 1/2" round red light is surprisingly noticeable. It seems as though you would never see it, but it really does light up well. On the PA28 I fly, it's tucked under the coaming (is that how it's spelt?), and so is in shade, which helps its visibility, I suppose. Even on a summer's day it sticks out like a sore thumb. I've gone with the same indicator on my project. Hope this helps. Nev -- Jodel D150 in progress UK ----- Original Message ----- From: "James Foerster" Subject: AeroElectric-List: Re: Stick-shaker for stall warning > Bob, it's a good question. My plane is a canvas for my ideas--oops, just came back from a chick-flick my wife wanted to see. I mean my plane is a flying test bed, and the stick-shaker may improve safety because it works without the headset on, it uses a sensory input that is hard to ignore, and the greatest threat to me is landing in the low and slow configuration. Why not just watch the AoA indicator? Well, my eyes are mainly out of the cockpit when landing, looking for traffic and my position in the pattern. Making that turn from downwind to base to final after a long flight to an unfamiliar airport can get me banked more than I might like. Add some wind shear, and traffic distraction, and the shaker might be worth it if it went off once in ten years. I agree that the audio warning might be enough, and that is why I've asked for the opinions of pilots with more experience than mine for their thoughts: is this worth doing? If audio stall warning were good enough, ! > why would both commercial and military planes have it? Figured it was worth some thought, anyway. > ________________________________ Message 3 _____________________________________ Time: 07:19:06 AM PST US From: Jim Sower Subject: Re: AeroElectric-List: Re: Stick-shaker for stall warning --> AeroElectric-List message posted by: Jim Sower I think you're right to install an audio stall warning driven by an accurate, reliable AoA. Like I said before, I don't know of any tactical military planes who have it. It contradicts the mission of tactical jets (back in my day) since critical parts of the mission were done at high AoA, on the fringes of buffet. The F-104 might well have had a stick shaker if, as I heard, it suffered from sudden departure into an unrecoverable flat spin, but that's an exception. An audio warning that would keep you away from the ubiquitous "approach turn stall" would be a very reasonable safety device. I think a stick shaker is a bit much. Accurate and Reliable AoA being the key words here .... Jim S. James Foerster wrote: > --> AeroElectric-List message posted by: "James Foerster" > ________________________________ Message 4 _____________________________________ Time: 08:01:41 AM PST US From: Jim Sower Subject: Re: AeroElectric-List: RE:Stick-shaker for stall warning --> AeroElectric-List message posted by: Jim Sower <... a ball bearing in a nonferrous tube ...> How about a little horn, available at the shack (or perhaps even Wal-Mart) for about ten bucks. Then we could get back to addressing actual problems ... Jim S. Carl Coulter wrote: > --> AeroElectric-List message posted by: Carl Coulter > > Motors? Eccentrics? We are electro-whizzies ;-) > u > How about a ball bearing in a non-ferros tube with a coil at each end? > Drive the coils with a multivibrator ckt to rattle the ball back and forth. > ________________________________ Message 5 _____________________________________ Time: 08:08:58 AM PST US Subject: Re: AeroElectric-List: Stick-shaker for stall warning From: Joel Harding --> AeroElectric-List message posted by: Joel Harding Ben, Didn't you ever have wind shear training? The stick shaker was invaluable in flying the max lift profile in a downburst or wind shear scenario. Fortunately I never had the opportunity to put that training to use. Joel Harding On Saturday, Oct 11, 2003, at 17:35 America/Denver, Benford2@aol.com wrote: > >> > I respect your comments, but > if a pilot does not recogonize lazy control imputs and lets the wings > stall > they need to practice more on slow flight. I am sure some aircrafts are > sensitive to stalls and the 72 is one of them but evey time I have > ever heard of > stick shaker going off it is on the cockpit voice recorder the NTSB > plays a few > days after a pilot kills himself and all the others on board. In all > my years > of flying the ONLY time I have ever heard the stall warning buzzer go > off was > during BFR's doing stalls. Tell me Ol Bob. in what situations have the > stick > shaker helped you out on your flying skills?? This is how I feel so > please > respect me for my comments. Peace.... > > Ben Haas N801BH. Jackson Hole Wy. > > > _- > ======================================================================= > _- > ======================================================================= > http://www.matronics.com/trouble-report > _- > ======================================================================= > _- > ======================================================================= > > > > ________________________________ Message 6 _____________________________________ Time: 08:34:31 AM PST US From: Benford2@aol.com Subject: Re: AeroElectric-List: Stick-shaker for stall warning --> AeroElectric-List message posted by: Benford2@aol.com In a message dated 10/12/2003 9:09:33 AM Mountain Daylight Time, cajole76@ispwest.com writes: > > Ben, > Didn't you ever have wind shear training? The stick shaker was > invaluable in flying the max lift profile in a downburst or wind shear > scenario. Fortunately I never had the opportunity to put that training > to use. > > Joel Harding > > My wind shear training consisted of recognizing the potential of wind shear, keep one hand on the throttle, one on the yoke to push forward and one big eye on the air speed indicator. All stick shakers,AOA's and other devices get their imput from air speed or air speed differential from the top of the wing to the bottom of it. My point is simply. why have a series of devices to monitor a symptom when the human brain can do it much faster from the initial problem when recognized properly. This whole topic keeps my mind flashing back to that Airbus that was doing a low pass in France showing off its GREAT fly by wire, everything is automatic, who the hell needs a pilot, this bells and whistles plane can do it all attitude. If I remember it correctly, that thing settled down in trees at the end of the runway with two of the MOST capable pilots unable to do a damn thing to stop it. My best training was when my instructor covered up the airspeed indicator and told me to feel out the control imputs and see how lazy they get with slower air flowing over them. To this day I can fly the plane without looking at the ASI and guestimate within 3--5 knots of indicated by just the feel of the planes controls. The human mind is a wonderful thing ya know... Faster then the best warning devices to date. As soon as a pilot starts depending on bells and whistles instead of common sense there will probably be an accident. Ben Haas. ________________________________ Message 7 _____________________________________ Time: 09:03:05 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Stick-shaker for stall warning --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:48 PM 10/11/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "James Foerster" > > >Bob wrote, >"I'm a little mystified about the concern. A stall warning > tone injected into the audio system is much easier to do." > >Bob, it's a good question. My plane is a canvas for my ideas--oops, just >came back from a chick-flick my wife wanted to see. I mean my plane is a >flying test bed, and the stick-shaker may improve safety because it works >without the headset on, it uses a sensory input that is hard to ignore, >and the greatest threat to me is landing in the low and slow >configuration. Why not just watch the AoA indicator? Well, my eyes are >mainly out of the cockpit when landing, looking for traffic and my >position in the pattern. Making that turn from downwind to base to final >after a long flight to an unfamiliar airport can get me banked more than I >might like. Add some wind shear, and traffic distraction, and the shaker >might be worth it if it went off once in ten years. I agree that >the audio warning might be enough, and that is why I've asked for the >opinions of pilots with more experience than mine for their thoughts: is >this worth doing? If audio stall warning were good enough, ! >why would both commercial and military planes have it? Figured it was >worth some thought, anyway. Sure . . . but let's consider the airplane characteristics that drive such requirements. First, how does the airplane behave at the edge of stall? Some aircraft I've flown do quite a bit of their own shaking. Other's didn't have enough up-elevator authority to push AOA past stall. Still others had such pronounced pitch-up deck-angles as to make one wonder why the airplane didn't break long ago. Some airplanes would break easy, mush nose-nose down and then recover only to break again . . . loosing altitude slowly in something akin to an aquarium performance of a porpoise. The airplanes that get the system designers attention are those that break quickly and/or are delicately roll-balanced and are likely to sneak up on the unwary pilot in vicious ways. How does your airplane behave? Do you plan to do a lot of low-altitude slow flight (like pipeline or power line patrol)? Do you plan to operate out of short and/or obstructed fields where max performance takeoff and landing techniques will be routinely employed? If any of these answers drive you toward a decision for extra-ordinary stall warning systems, perhaps your airplane is a good candidate for a true AOA indicator systems and any attendant warnings it might provide. I can't remember the last time I heard the stall warning go off on any airplane I've rented recently . . . and certainly if it did, it was in the flare a few feet above the runway. For the kinds of airplanes I have access to and the way I use them, I consider a stall warning system completely unnecessary. If I found a stall warning system to be inoperative at pre-flight, I would not cancel the flight. Irrespective of the range of comments, suggestions and opinions presented on this topic over the past few days, it's a combination of performance of your airplane combined with your skills in the operating environment that you plan to work that drive the considered decision and elegant solution. I would suggest that your airplane has few performance characteristics in common with air transport or fighter aircraft. If the designer was doing his job, benign handling characteristics in slow flight was a goal. I'd suggest you get the airplane flying, and during the 40-hours of obligatory fly-off, go find out how your airplane behaves at 3000 feet. If it scares the socks off you at altitude, then the exercise of plan-B is very much in order. Bob . . . ________________________________ Message 8 _____________________________________ Time: 09:07:26 AM PST US From: Kevin Horton Subject: Re: AeroElectric-List: Re: Stick-shaker for stall warning --> AeroElectric-List message posted by: Kevin Horton >--> AeroElectric-List message posted by: Jim Sower > >I think you're right to install an audio stall warning driven by an >accurate, reliable AoA. Like I said before, I don't know of any >tactical military planes who have it. It contradicts the mission of >tactical jets (back in my day) since critical parts of the mission >were done at high AoA, on the fringes of buffet. The F-104 might >well have had a stick shaker if, as I heard, it suffered from sudden >departure into an unrecoverable flat spin, but that's an exception. >An audio warning that would keep you away from the ubiquitous >"approach turn stall" would be a very reasonable safety device. I >think a stick shaker is a bit much. >Accurate and Reliable AoA being the key words here .... Jim S. > Tactical military jets have a very different set of mission requirements than most homebuilts. And the pilots have much more training than many general aviation pilots, and they fly more hours per year in their aircraft than many general aviation pilots do. So I'm not sure we should use tactical military jets as a yardstick to see whether a stick shaker makes sense in a homebuilt aircraft. -- Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://go.phpwebhosting.com/~khorton/rv8/ ________________________________ Message 9 _____________________________________ Time: 09:31:16 AM PST US From: Benford2@aol.com Subject: Re: AeroElectric-List: Re: Stick-shaker for stall warning --> AeroElectric-List message posted by: Benford2@aol.com In a message dated 10/12/2003 10:03:53 AM Mountain Daylight Time, bob.nuckolls@cox.net writes: > > Irrespective of the range of comments, suggestions and > opinions presented on this topic over the past few days, > it's a combination of performance of your airplane combined > with your skills in the operating environment that you plan > to work that drive the considered decision and elegant > solution. I would suggest that your airplane has few > performance characteristics in common with air transport > or fighter aircraft. If the designer was doing his job, > benign handling characteristics in slow flight was a > goal. I'd suggest you get the airplane flying, and > during the 40-hours of obligatory fly-off, go find > out how your airplane behaves at 3000 feet. If it > scares the socks off you at altitude, then the exercise > of plan-B is very much in order. > > Bob . . . > > Bingo, That Bob is sooooo good at relaying the proper answer.. Ben Haas. do not archive. ________________________________ Message 10 ____________________________________ Time: 09:39:30 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Alternator Noise in Headset --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:27 PM 10/10/2003 -0700, you wrote: >Bob, > > I've posted this meesage twice to the Aeroelectric Matronics list, and > I see it there, but haven't seen any response. Not that I've earned your > immediate jump-when-I-say-jump response by any means, but seeing how you > quickly respond to others makes me wonder if you're seeing this. Or do I > owe you money? > Please respond either to the list or offline to me at > pedroagua@aol.com if you get this. > >Thanks, >Pete Waters >(in Watsonville in November) No, you don't owe me money. My time to work the AeroElectric-List comes in variable sized pieces. Some replies can be generated in less than a minute, others take some time to consider and craft a reply. In order NOT to fall hopelessly behind, I always start with the most recent posts and work my way backwards in time. Your question was lengthy and needed some time to consider, hence on a nice, quiet Sunday morning, I've got a chunk of time sufficient to the task . . . >Bob, > > Apologies if this is a duplicate post; I seem to have trouble getting > this out. > I'm starting to develop an electrical problem in my RV-4 and I'm hoping > you can help me diagnose it. > I bought the RV-4 (completed) last year. It was built in 1988 and I'm > the fourth owner. It's a solid airplane, but the documentation is thin > and from the logbooks it appears that the electrical stuff (lights, > radios) were added piecemeal over the plane's first few years, so the > electrical system is a bit tangled. For example, my nav light circuit > breaker kept popping. I finally figured out that the builder / modifier > has three 2-amp bulbs (6 amps) going through a 5-amp CB. So, after > consulting the wire selection graph, I replaced the 5A CB with a 10A > CB. Worked great. > However, on my next flight, I started hearing a whine in my > headset. More of a high-pitched tone, actually. I realized that it was > a solid tone that was being cut off intermittently, making it sounding a > lot like Morse from an VOR. As I returned from a cross country it got > louder and became almost constant. The whine / tone is present with the > radios off, strobes off, and alternator off, although I didn't think to > pull the breakers on those circuits. Pulling the breakers would probably not have made any difference. Turning the systems off with the panel mounted controls is sufficient. > I don't hear it on deck with all the avionics running off the RG > battery. Inflight I can hear it in the background during intercom use > and radio reception. It disappears briefly after a radio transmission and > then returns after a few seconds. The plane has a VDO analog voltmeter, > no ammeter. ( I plan to install an VA-1A EI volt/ammeter shortly.) As > I heard the tone inflight I immediately noticed that the voltage was > increasing to about 15.5 V and fluctuating there for a while. Then it > settled down to 14.5 V or so. The > problem comes and goes and is not entirely repeatable. The voltmeter > reads 14.0 volts on deck with just the battery on and the engine not > running (no alternator), so I think the VDO voltmeter is accurate. Battery only operations seldom exceed 13.0 volts. Most RG batteries have an open circuit voltage of 12.9 volts at room temperature. If your voltmeter is saying "14.0", then it's off by at least 1.0 volt. > Also, perhaps related and perhaps not, the LORAN started telling me a > few weeks back, before I heard any of this headset noise, that I was in > the Southern Hemisphere when I was flying across Oregon. I had thought > the LORAN had just died due to age, and I was buying a GPS anyway, so > I've just turned it off and planned to remove it. Okay. > Initially I was thinking the obvious thought that the alternator's > going. After reading the Aeroelectric Connnetion I'm wondering if it > might not be the voltage regulator. Because the plane has so little > documentation, I don't know the specifics of the alternator at all or how > old it is, just that it's been working well so far. My A&P found nothing > wrong with it at the last annual 60 hours ago. I'm wondering if the > impending alternator / regulator failure is putting out RF that's getting > into the headset and was jamming the LORAN. (It turns out that the LORAN > had locked onto the wrong nav solution -- that whole "two solutions to > the quadratic equation" thing. Letting it sit on deck for a few minutes > with the engine off allowed it to "find itself" correctly back in > California. But I'm still wondering if the initial event of it getting > lost wasn't related to LORAN signal jamming >from the alternator / regulator.) If the noise is present with the alternator OFF, then I don't see how this system can be involved. Does the tone vary in pitch with engine rpm . . . alternator generated noises do vary in pitch with rpm and they go away when the alternator is turned off. > Also, I noticed in flight that with the electrical system fully loaded > up, the voltmeter needle also starts rapidly fluctuating at > 14.5-15.5V. I see this when I turn on the landing light. Due to the > lack of documentation I have no idea how many total amps are actually > flowing through the system, so I'm wondering if turning on the landing > lights actually >puts the plane's total current draw above the rated output of the >alternator. Is fluctuating system voltage a sign of that? No, it's more likely a separate problem, here's a post I did on this topic a few weeks ago: ------------------------------------------------------ >At 11:58 PM 8/27/2003 -0400, you wrote: >I felt pretty certain that if you recommended hooking the regulator right >to the back of the alternator, and then followed the appropriate >connection you knew things would settle down nicely. Well, they did just >that! The ammeter was rock steady to the charging side, and the voltage >read a solid 14.4 >Now the follow up to get these same results once the voltage regulator is >reinstalled, and not hanging off the alternator. The other thing I noted >was that when hooked up in this manner the alternator side of the split >master was not working, but I'm sure you knew that would happen. > >Let me know what's next, and thanks! Okay, this experiment was important to tell us that the components were okay and that you didn't have a flaky regulator or bouncing brushes in the alternator. I'd start at the bus (did I ask whether you're using fuseblocks or breakers?) and check to see that you have good terminals, at least 20AWG wire all the way to the regulator's "A/S" terminals. If the regulator is mounted on the firewall, grounding isn't an issue for the regulator . . . and seldom does grounding affect stability . . . only voltage setting. Also, you mentioned that the "alternator side of the split master was not working" . . . I'd bet that MOST of your circuit resistance is happening in that switch. I have a plastic bag full of perfectly good looking split-rocker switches that were sent to me after putting in a new one cured a bouncy ammeter complaint. This has occurred in countless certified ships and a few OBAM aircraft. This doesn't mean that the split-rocker is necessarily a "bad" product (it's made by Carling and uses the same guts as the S700 series toggle switches B&C sells). Regulators are sensitive to small amounts of resistance in the lines between bus and regulator. I had one builder who mounted his regulator within a few inches of the bus, tied the A/S terminals directly to the breaker with short, single, solid wire and put his alternator control switch in series with the field wire. He added crowbar ov protection to the breaker and ended up with a combination that would probably be stable over the lifetime of the airplane. In older production Cessnas, I think I counted 20 some odd crimps, connections and spring-pressure maintained metal-metal contacts between bus and regulator. As all of these joints age, they add resistance to the circuit. At some point in time, the system becomes unstable with symptoms you have observed. Thousands of spam-can owners have paid out $millions$ to ignorant mechanics who replaced EVERYTHING BUT aged/compromised wiring before finally renewing the bus-to-regulator components. In many cases, owners have reported that replacing only the spilt-rocker "fixed" the problem. Indeed this single component can be a major contributor of total loop resistance. But consider that if NEW loop resistance was on the order of 50 milliohms and had climbed to 100 milliohms with the switch contributing 25 ohms of de-stabilizing resistance. Replacing the switch drops total down to 75 milliohms and the regulator is happy again . . . but not for as long as it would be when replacing ALL sources of age/service related resistance in the bus-to-regulator pathway. The obvious, elegant solution in original design is to incorporate a regulator that separates voltage sense wires from field current supply wires. The LR-3 does just that. Any new regulators I design will have separate sense wires too. Does this suggest that the OBAM community should rip out all their three-terminal switchers and bolt on the LR-3? Not at all. The automotive style regulators have for the most part given good value but they DO have special characteristics that only one mechanic in 1000 understands. In the spam-can world, ignorance is shoveled out at $thousands$ per non-idea, in the OBAM aircraft world, we've managed to keep those costs MUCH lower . . . and much of it happens right here on the AeroElectric List. > This airplane is well-built structurally and the engine's in good > shape, but the more I look at the electrical system, the more I relaize > that it's not quite what I'd like to see. Since avionics and lights were > added piecemeal over the years by different people, I wouldn't be > surprised to see as basic a mistake as an undercapacity > alternator. (Remember the undercapacity CB I found.) The largest Full-Up IFR load I've calculated for an SE airplane with vacuum system is 27A, with electric gyros it was 31A. It is unlikely that your alternator is undersized. If the noise were present with the alternator ON, varies pitch with rpm and goes away alternator OFF, it might be that onset of the noise was due to failure of a diode in the alternator which would produce a combination of (1) reduced alternator capacity and (2) greatly increased noise on the bus. However, since I think we're talking about relatively fixed pitch noise with alternator OFF, this isn't root cause of the noise. > Lastly, I'm also noting that the whine showed up within two flight > hours of my replacing the nav lights circuit breaker. Although I can't > imagine why that would have an effect, I also should mention that the > circuit breaker panel is homemade and possibly not well > shielded; perhaps in the course of working with the panel to swap out > the breaker I changed something. > If you could offer any thoughts on this, I'd appreciate it. First impressions are that this system may be suffering from a variety of small illnesses common to electrical system architectures used in most spam cans. These problems can be made worse by marginal craftsmanship of the neophyte builder and ignorant mechanic. Just because you hear a noise in the headsets doesn't always mean that some antagonist has jumped up to torment the victim. It's not uncommon for a victim to have ailments that mimic externally generated noises. Do you hear the noise whether or not there is a radio transmission being received? I.e., heard in the intercom only with microphone and radio squelch gates closed? Is the intercom battery powered or powered from the bus? If battery powered, how about trying a new battery . . .some audio systems become squealers when the battery voltage drops and power source impedance goes up. >Best, >Pete Waters >(registered for your class in Watsonville) Great. See you in a few weeks! Given the range and magnitude of problems you've noted, it's not out of line to consider some major surgery to keep things like this from rising out of the mud in the future. We could use your airplane as a study topic at the Watsonville seminar. Bring all the drawings you have. Bob . . . ________________________________ Message 11 ____________________________________ Time: 09:56:46 AM PST US From: "John Perry" Subject: AeroElectric-List: Stick Shakers --> AeroElectric-List message posted by: "John Perry" Nowadays in commercial jets we practice a lot of windshear recoveries. When ground contact is immanent we fly intermittent stick shaker to recover. The stick shaker comes on before a stall because these airplanes don't have such nice stall recoveries and there have been times when you need every bit of performance you can get. So we use the stick shaker every year in the simulator (stimulator) and hopefully never have it for real in the airplane. It does get your attention. Probably not necessary though in a light plane with more aerodynamic stall warning and docile stalls. But there have been a significant number of turn to final stalls that were not recovered from. My friend was killed like that 35 years ago. John 757,767,MD-11 etc. Long Ez, (That's the answer just get a canard!) ________________________________ Message 12 ____________________________________ Time: 09:58:14 AM PST US Subject: Re: AeroElectric-List: Re: Stick-shaker for stall warning From: caspainhower@aep.com 10/12/2003 12:58:10 PM --> AeroElectric-List message posted by: caspainhower@aep.com >I'm not sure we should use tactical military jets as a yardstick to see whether a stick shaker makes sense in a homebuilt aircraft. I'm wondering if some people have missed the point here. I think it is a fact not worth debating that stall warning devices have saved lives, even if some pilots on this list are of such a high skill level as to not need them. The question had to do with how to make a stick-shaker. As a builder we get to make our own decision what we will ultimately use. Having said that here's my opinion. I think it sounds like a novel idea and would probably provide a suitable warning, but I will stick with an audible device. Craig S. 601 XL not quite half done. This e-mail message and all attachments transmitted with it from the Nuclear Generation Group of American Electric Power are for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. ________________________________ Message 13 ____________________________________ Time: 12:08:28 PM PST US From: Pete Waters Subject: Re: AeroElectric-List: Re: Alternator Noise in Headset --> AeroElectric-List message posted by: Pete Waters "Robert L. Nuckolls, III" wrote: --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:27 PM 10/10/2003 -0700, you wrote: >Bob, > > I've posted this meesage twice to the Aeroelectric Matronics list, and > I see it there, but haven't seen any response. Not that I've earned your > immediate jump-when-I-say-jump response by any means, but seeing how you > quickly respond to others makes me wonder if you're seeing this. Or do I > owe you money? > Please respond either to the list or offline to me at > pedroagua@aol.com if you get this. > >Thanks, >Pete Waters >(in Watsonville in November) No, you don't owe me money. My time to work the AeroElectric-List comes in variable sized pieces. Some replies can be generated in less than a minute, others take some time to consider and craft a reply. In order NOT to fall hopelessly behind, I always start with the most recent posts and work my way backwards in time. Your question was lengthy and needed some time to consider, hence on a nice, quiet Sunday morning, I've got a chunk of time sufficient to the task . . . <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< You're a gentleman and a scholar and I apologize for my impatience. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >Bob, > > Apologies if this is a duplicate post; I seem to have trouble getting > this out. > I'm starting to develop an electrical problem in my RV-4 and I'm hoping > you can help me diagnose it. > I bought the RV-4 (completed) last year. It was built in 1988 and I'm > the fourth owner. It's a solid airplane, but the documentation is thin > and from the logbooks it appears that the electrical stuff (lights, > radios) were added piecemeal over the plane's first few years, so the > electrical system is a bit tangled. For example, my nav light circuit > breaker kept popping. I finally figured out that the builder / modifier > has three 2-amp bulbs (6 amps) going through a 5-amp CB. So, after > consulting the wire selection graph, I replaced the 5A CB with a 10A > CB. Worked great. > However, on my next flight, I started hearing a whine in my > headset. More of a high-pitched tone, actually. I realized that it was > a solid tone that was being cut off intermittently, making it sounding a > lot like Morse from an VOR. As I returned from a cross country it got > louder and became almost constant. The whine / tone is present with the > radios off, strobes off, and alternator off, although I didn't think to > pull the breakers on those circuits. Pulling the breakers would probably not have made any difference. Turning the systems off with the panel mounted controls is sufficient. > I don't hear it on deck with all the avionics running off the RG > battery. Inflight I can hear it in the background during intercom use > and radio reception. It disappears briefly after a radio transmission and > then returns after a few seconds. The plane has a VDO analog voltmeter, > no ammeter. ( I plan to install an VA-1A EI volt/ammeter shortly.) As > I heard the tone inflight I immediately noticed that the voltage was > increasing to about 15.5 V and fluctuating there for a while. Then it > settled down to 14.5 V or so. The > problem comes and goes and is not entirely repeatable. The voltmeter > reads 14.0 volts on deck with just the battery on and the engine not > running (no alternator), so I think the VDO voltmeter is accurate. Battery only operations seldom exceed 13.0 volts. Most RG batteries have an open circuit voltage of 12.9 volts at room temperature. If your voltmeter is saying "14.0", then it's off by at least 1.0 volt. > Also, perhaps related and perhaps not, the LORAN started telling me a > few weeks back, before I heard any of this headset noise, that I was in > the Southern Hemisphere when I was flying across Oregon. I had thought > the LORAN had just died due to age, and I was buying a GPS anyway, so > I've just turned it off and planned to remove it. Okay. > Initially I was thinking the obvious thought that the alternator's > going. After reading the Aeroelectric Connnetion I'm wondering if it > might not be the voltage regulator. Because the plane has so little > documentation, I don't know the specifics of the alternator at all or how > old it is, just that it's been working well so far. My A&P found nothing > wrong with it at the last annual 60 hours ago. I'm wondering if the > impending alternator / regulator failure is putting out RF that's getting > into the headset and was jamming the LORAN. (It turns out that the LORAN > had locked onto the wrong nav solution -- that whole "two solutions to > the quadratic equation" thing. Letting it sit on deck for a few minutes > with the engine off allowed it to "find itself" correctly back in > California. But I'm still wondering if the initial event of it getting > lost wasn't related to LORAN signal jamming >from the alternator / regulator.) If the noise is present with the alternator OFF, then I don't see how this system can be involved. Does the tone vary in pitch with engine rpm . . . alternator generated noises do vary in pitch with rpm and they go away when the alternator is turned off. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< I'll have to check that on the next flight. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> > Also, I noticed in flight that with the electrical system fully loaded > up, the voltmeter needle also starts rapidly fluctuating at > 14.5-15.5V. I see this when I turn on the landing light. Due to the > lack of documentation I have no idea how many total amps are actually > flowing through the system, so I'm wondering if turning on the landing > lights actually >puts the plane's total current draw above the rated output of the >alternator. Is fluctuating system voltage a sign of that? No, it's more likely a separate problem, here's a post I did on this topic a few weeks ago: ------------------------------------------------------ >At 11:58 PM 8/27/2003 -0400, you wrote: >I felt pretty certain that if you recommended hooking the regulator right >to the back of the alternator, and then followed the appropriate >connection you knew things would settle down nicely. Well, they did just >that! The ammeter was rock steady to the charging side, and the voltage >read a solid 14.4 >Now the follow up to get these same results once the voltage regulator is >reinstalled, and not hanging off the alternator. The other thing I noted >was that when hooked up in this manner the alternator side of the split >master was not working, but I'm sure you knew that would happen. > >Let me know what's next, and thanks! Okay, this experiment was important to tell us that the components were okay and that you didn't have a flaky regulator or bouncing brushes in the alternator. I'd start at the bus (did I ask whether you're using fuseblocks or breakers?) and check to see that you have good terminals, at least 20AWG wire all the way to the regulator's "A/S" terminals. If the regulator is mounted on the firewall, grounding isn't an issue for the regulator . . . and seldom does grounding affect stability . . . only voltage setting. Also, you mentioned that the "alternator side of the split master was not working" . . . I'd bet that MOST of your circuit resistance is happening in that switch. I have a plastic bag full of perfectly good looking split-rocker switches that were sent to me after putting in a new one cured a bouncy ammeter complaint. This has occurred in countless certified ships and a few OBAM aircraft. This doesn't mean that the split-rocker is necessarily a "bad" product (it's made by Carling and uses the same guts as the S700 series toggle switches B&C sells). Regulators are sensitive to small amounts of resistance in the lines between bus and regulator. I had one builder who mounted his regulator within a few inches of the bus, tied the A/S terminals directly to the breaker with short, single, solid wire and put his alternator control switch in series with the field wire. He added crowbar ov protection to the breaker and ended up with a combination that would probably be stable over the lifetime of the airplane. In older production Cessnas, I think I counted 20 some odd crimps, connections and spring-pressure maintained metal-metal contacts between bus and regulator. As all of these joints age, they add resistance to the circuit. At some point in time, the system becomes unstable with symptoms you have observed. Thousands of spam-can owners have paid out $millions$ to ignorant mechanics who replaced EVERYTHING BUT aged/compromised wiring before finally renewing the bus-to-regulator components. In many cases, owners have reported that replacing only the spilt-rocker "fixed" the problem. Indeed this single component can be a major contributor of total loop resistance. But consider that if NEW loop resistance was on the order of 50 milliohms and had climbed to 100 milliohms with the switch contributing 25 ohms of de-stabilizing resistance. Replacing the switch drops total down to 75 milliohms and the regulator is happy again . . . but not for as long as it would be when replacing ALL sources of age/service related resistance in the bus-to-regulator pathway. The obvious, elegant solution in original design is to incorporate a regulator that separates voltage sense wires from field current supply wires. The LR-3 does just that. Any new regulators I design will have separate sense wires too. Does this suggest that the OBAM community should rip out all their three-terminal switchers and bolt on the LR-3? Not at all. The automotive style regulators have for the most part given good value but they DO have special characteristics that only one mechanic in 1000 understands. In the spam-can world, ignorance is shoveled out at $thousands$ per non-idea, in the OBAM aircraft world, we've managed to keep those costs MUCH lower . . . and much of it happens right here on the AeroElectric List. > This airplane is well-built structurally and the engine's in good > shape, but the more I look at the electrical system, the more I relaize > that it's not quite what I'd like to see. Since avionics and lights were > added piecemeal over the years by different people, I wouldn't be > surprised to see as basic a mistake as an undercapacity > alternator. (Remember the undercapacity CB I found.) The largest Full-Up IFR load I've calculated for an SE airplane with vacuum system is 27A, with electric gyros it was 31A. It is unlikely that your alternator is undersized. If the noise were present with the alternator ON, varies pitch with rpm and goes away alternator OFF, it might be that onset of the noise was due to failure of a diode in the alternator which would produce a combination of (1) reduced alternator capacity and (2) greatly increased noise on the bus. However, since I think we're talking about relatively fixed pitch noise with alternator OFF, this isn't root cause of the noise. > Lastly, I'm also noting that the whine showed up within two flight > hours of my replacing the nav lights circuit breaker. Although I can't > imagine why that would have an effect, I also should mention that the > circuit breaker panel is homemade and possibly not well > shielded; perhaps in the course of working with the panel to swap out > the breaker I changed something. > If you could offer any thoughts on this, I'd appreciate it. First impressions are that this system may be suffering from a variety of small illnesses common to electrical system architectures used in most spam cans. These problems can be made worse by marginal craftsmanship of the neophyte builder and ignorant mechanic. Just because you hear a noise in the headsets doesn't always mean that some antagonist has jumped up to torment the victim. It's not uncommon for a victim to have ailments that mimic externally generated noises. Do you hear the noise whether or not there is a radio transmission being received? <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Yes, the noise was overlaid on received radio transmissions. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I.e., heard in the intercom only with microphone and radio squelch gates closed? Is the intercom battery powered or powered from the bus? <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< From what I've determined the electrical architecture in this plane is such a kludge that there ARE no distinct busses. For example, in the circuit breaker panel, the ground sides of the CBs are wired together with 14AWG wire, CB to CB in series, rather than in parallel to a bus (which could have been as simple as a piece of copper). As you mention in the Connection, obviously not the way to do it. I'll show it to you in Watsonville. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> If battery powered, how about trying a new battery . . .some audio systems become squealers when the battery voltage drops and power source impedance goes up. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Yesterday I flew a short hop battery-only (alternator switch off) and didn't hear any tone. As I recall voltage was about 13 V. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >Best, >Pete Waters >(registered for your class in Watsonville) Great. See you in a few weeks! Given the range and magnitude of problems you've noted, it's not out of line to consider some major surgery to keep things like this from rising out of the mud in the future. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< That's what I'm concluding. I think I may be spending the next year or so redesigning and rebuilding most of the electrical architecture in this airplane. My initial thoughts are to start at the CB panel and properly divide the system into main, essential, and battery busses. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> We could use your airplane as a study topic at the Watsonville seminar. <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< I'll bring it if weather permits me to get into Watsonville VFR. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bring all the drawings you have. Bob . . . <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< The only drawings I have are the ones I'm making through reverse engineering! But it's certainly educational. Thanks again. --------------------------------- ________________________________ Message 14 ____________________________________ Time: 02:42:09 PM PST US From: "Ernest Kells" Subject: Re: AeroElectric-List: Re: Alternator Noise in Headset --> AeroElectric-List message posted by: "Ernest Kells" Pete: I understand your frustration at the electrical stuff. It's confusing - not like driving rivets (even visitors can point out my smilies). Bob very generously maintains this List for hundreds of subscribers. Once each year he asks for a totally voluntary contribution to help him provide the software, hardware, technical resource and archive storage for the benefit of everyone. BTW: have you made your contribution in the last 12 months ? ? Bob also provides a LOT of answers to people who submit questions to the List. In doing this he is only one participant on this List, equal to the rest of us. We all would respond to these questions - if we could. Bob answers based on his considerable knowledge - and we all defer to his expertise. This is his gift. If you don't like it you should drop the List and deal with your nearest service shop on a time and materials basis. The rest of us pay tribute to Mecca (er.. the sage of Wichita). Happy building. Ernest Kells - RV-9A O235-N2C, Wood Prop 90 plus % Complete - Wiring > > I've posted this meesage twice to the Aeroelectric Matronics list, and > > I see it there, but haven't seen any response. Not that I've earned your > > immediate jump-when-I-say-jump response by any means, but seeing how you > > quickly respond to others makes me wonder if you're seeing this. Or do I > > owe you money? > > Please respond either to the list or offline to me at > > pedroagua@aol.com if you get this. Thanks, Pete Waters ________________________________ Message 15 ____________________________________ Time: 04:07:12 PM PST US Subject: RE: AeroElectric-List: Stick-shaker for stall warning From: "Scott, Ian" --> AeroElectric-List message posted by: "Scott, Ian" HI Jim, I have just finished my J400, and the stall characteristics are very benign, much better than the older 2 seater Jabiru that I have a few hundred hours in. If you are installing the audible stall warning horn, this is more than enough protection than you need. If you wish to fully explore the very edge of the stall envelope near the ground, then may I suggest a AOA system. Ian -----Original Message----- From: James Foerster [mailto:jmfpublic@comcast.net] Subject: AeroElectric-List: Stick-shaker for stall warning --> AeroElectric-List message posted by: "James Foerster" Friends, I'm building a 4 place Jabiru, and this has a central control stick. I am considering the addition of a stick-shaker as used by military and commercial planes. A model airplane motor, run at the "appropriate" speed and driving an eccentric weight should work. The tiny pager motors available on the surplus market are too small to be useful in a vibrating plane, however. Could you professional pilots give me an idea as to how far the stick moves, and at roughly what frequency? I suspect that 8-20 Hz would be optimum, based on no real data. Its hard to guess the motion needed as this will be frequency dependent. I would drive this motor from either a microswitch attached to a vane projecting out from the leading edge of the wing, as is used by many commercial planes with an electric stall warning device, or else drive it from an angle of attack instrument. Although auditory warning from AoA devices is good, the stall is the greatest risk for death at takeoff and landing phase of flight. The warning should not be subtle and should use several modalities. I look forward to your comments. Jim Foerster Friends, I'm building a 4 place Jabiru, and this has a central control stick. I am considering the addition of a stick-shaker as used by military and commercial planes. A model airplane motor, run at the "appropriate" speed and driving an eccentric weight should work. The tiny pager motors available on the surplus market are too small to be useful in a vibrating plane, however. Could you professional pilots give me an idea as to how far the stick moves, and at roughly what frequency? I suspect that 8-20 Hz would be optimum, based on no real data. Its hard to guess the motion needed as this will be frequency dependent. I would drive this motor from either a microswitch attached to a vane projecting out from the leading edge of the wing, as is used by many commercial planes with an electric stall warning device, or else drive it froman angle of attack instrument. Although auditory warning from AoA devices is good, the stall is the greatest risk for death at takeoff and landing phase of flight. The warning should not be subtle and should use several modalities. I look forward to your comments. Jim Foerster ---------------------------------------------------- RSL COM has an extensive and competitive range of local and long distance call packages. 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Any views expressed in this message are those of the individual sender, except where the message states otherwise and the sender is authorised to state them to be the views of any such entity. ---------------------------------------------------- ________________________________ Message 16 ____________________________________ Time: 08:44:49 PM PST US From: "John Perry" Subject: AeroElectric-List: Strobes and comm Ant --> AeroElectric-List message posted by: "John Perry" Friends, I'm building an AeroCanard and my Comm Ant are in the winglets. Problem is I have to run the strobe wiring out the same hole. Does anyone have an opinion on this? Will it work? John ________________________________ Message 17 ____________________________________ Time: 09:00:15 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Alternator Noise in Headset --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:35 PM 10/12/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Ernest Kells" > > >Pete: I understand your frustration at the electrical stuff. It's >confusing - not like driving rivets (even visitors can point out my >smilies). > >Bob very generously maintains this List for hundreds of subscribers. Once >each year he asks for a totally voluntary contribution to help him provide >the software, hardware, technical resource and archive storage for the >benefit of everyone. BTW: have you made your contribution in the last 12 >months ? ? Actually, ALL donations go to Matt Dralle at matronics.com to support his efforts in supplying both server space and the fine software that runs the lists. My time spent on the lists is in exchange for making folks aware of my products and services. I've spent $thousands$ for print ads that produced not a single phone call much less a sale. I figure time on the list is a much better return on investment in at least three ways:. (1) You folks are helping me become a better designer and teacher by providing both venue and participants willing to think outside the box . . . (2) The attention this list brings to my website and its offerings makes this a hobby that does better-than-break even. I'm amazed that certain politicians in CA paid less than a grand in taxes on millions of income citing LOSSES on a publishing and lecturing business . . . I'm still trying to figure out how that works. This business wouldn't support me - at least not yet. But in no year have I not paid taxes on profits much less washed out taxes on my income as an engineer at RAC. So, you see this isn't so much an act of "generosity" as it is a symbiotic relationship where I hope every List participant is here because they receive good value for their time and purchases. >Bob also provides a LOT of answers to people who submit questions to the >List. In doing this he is only one participant on this List, equal to the >rest of us. We all would respond to these questions - if we could. Bob >answers based on his considerable knowledge - and we all defer to his >expertise. This is his gift. If you don't like it you should drop the List >and deal with your nearest service shop on a time and materials basis. The >rest of us pay tribute to Mecca (er.. the sage of Wichita). Happy building. >Ernest Kells - RV-9A O235-N2C, Wood Prop Gently, gently my friend. I'm sure Pete now understands how this all works and will be an active and useful participant to the list. Lookit . . . he's signed up for my Watsonville seminar. Let's not beat up on one of my customers now ;-) I couldn't do this if it wasn't fun, educational and ultimately profitable. The 'Connection is going to be my retirement business when they boot me out of RAC (or I leave 'cause it isn't fun any more). After a few hours of jousting with regulatory and corporate bureaucrats in the certified world, I can't wait to open my mail and see what kind of dragons can be slain TODAY in the OBAM community. So for the final reason . . . (3) the AeroElectric List provides a way for me to see real-time progress in crafting solutions to design and maintenance problems. If it weren't for you guys, the molasses-in-January pace of progress in my real job might have convinced me to open a BBQ stand years ago. At least there, when last week's customer walks back in the door today, you know you've done a good thing for both him and yourself. It can take years to achieve similar degrees of feedback in aviation . . . unless you're here on the AeroElectric-List. Let's cut Pete a little slack and put our heads together to see if we can figure out what's wrong with his airplane. Sound's like a real puzzlement and I'm looking forward to seeing what it turns out to be. Bob . . . ________________________________ Message 18 ____________________________________ Time: 09:29:22 PM PST US From: richard@riley.net Subject: AeroElectric-List: Grounding fuel flow sender --> AeroElectric-List message posted by: richard@riley.net I'm rebuilding the induction system on a Lyc IO-540. There's a Floscan transducer there already, from a previous engine instrument installation, but it looks like I'm going to have to re-position it. I know about keeping the fuel flow straight for as long as possible going in and out of the transducer, but at one point I was told that the transducer shouldn't be grounded - that it should be stepped off the engine on insulators, and that the fuel lines before and after the transducer should be rubber. This doesn't make a whole lot of sense to me, and I *really* don't want anything but stainless line for fuel on that side of the firewall. Does anyone know if this bit of advice is true, urban legend, or something inbetween?