![]() |
Mags fail too.
There, issue settled in just three words. Another public service ;) Come on guys, steer it back over there to the magenta line.... |
Quote:
![]() |
This thread has seen some enthusiastic opinions expressed but to date it has been reasonably civilised and some interesting information has emerged. So let's keep it that way.
I think that one of the problems in assessing the reliability of experimental ignition systems is the tendency for non-disclosure of actual failures. This is certainly true of the manufacturers of the systems. Try to get some failure data from EMAG or LightSpeed and you will come up against a stonewall. So we on VansAirforce are largely left with forming opinions on the reliability of Experimental electronic ignitions largely based on forum reports from disgruntled users. The question that therefore needs to be asked is whether actual builders/pilots are prepared to make those disclosures on a public forum. My guess is that, in the main, they are not. And there is a logical reason for that. Does it make sense to bag Brad or Klaus's products in public when they are the only people that you can turn to to support your installation with maintenance and spare parts. I don't think so. That leads me to believe that the reports of failures that we get are only a minor percentage of the real problems that arise with these systems. In other words the track record of these products is probably worse than you think. And I don't think that this problem off non-disclosure applies to just experimental ignition systems. I think it probably applies in respect of all complex solid state experimental devices (e.g. EFISs) produced by essentially very small companies to whom the end user is totally dependent for ongoing support. So I believe that there is a very large disincentive for users to complain publicly about their experimental ignitions when they have problems. On the lesser side it might damage relations with a party upon whom they rely. On the more serious side too much bad press might actually affect sales of the product leading to collapse of what is probably a very small and financially brittle company resulting in installed ignition systems being orphaned. |
Some of the emotion centers around the timing failures, as they can be very inconvenient at times when we are expecting a reliable airplane. As mentioned, the same failure phenomenon applies to many other things on the airplane besides the ignition systems. That's why it is good to have a different backup and not put all of the proverbial eggs in one basket.
Sure we have a single engine airplane when talking about the RV's, but there are ways to eliminate some of the risk---- mechanical and electric fuel pumps, one mag and one electronic ignition (NOT dual electronic ignitions), dual alternators, regular maintenance, etc. For EFIS's, I'm one who believes that the backup should be of a different manufacturer and protected as best as possible from an aircraft electrical problem. No sense frying everything when the alternator fails with over voltage. Most likely everything about our airplanes could fail at some time. The idea is to minimize the risk while taking advantage of increases in performance. Otherwise we would just stay at home and watch TV. :) Pretty soon, the electronic ignitions are going to rank up there with the primer wars. :) Vic |
Quote:
|
Well, I'll break the mold here and publish our stats if you care to believe them. I published this (with some new additions) on another aircraft forum a while back. Note, most of our systems for aircraft, outside of military usage, are integrated fuel and ignition systems so more complex than ignition-only products. I've presented the whole history here to the best of our records and my recollections. If you're a direct SDS customer, feel free to ad any comments, negative or positive.
The stats on our electronics, compiled over the last 20+ years (reported to us or observed personally, attributed to actual electronic component failure): 550,000 + flight hours on over 1850 systems High time ECU- 145,000 hours (bench test one) High time fliers of our systems- 1500 hours (Rover V8), 1700 hrs (Lycoming O-360 and Subaru), 2 at 2000+ hours (Rotax 912 and Jabiru used for flight training) High time automotive system (EM-1, circa 1994 used in 5 different cars- estimated 12,000+ hours). ECU failures on aircraft- zero Crank sensor failures- zero EJ25 coil pack failures- zero Fuel pump failures- zero (2 failed when improperly mounted) Wiring harness failures- zero Injector failures- 2 unconfirmed (claimed but never sent back for our inspection) Temp sensor failures- 2 in aircraft (non-critical system failure and new fix applied 5 years ago) MAP sensor failures- 5 in aircraft (non-critical failure, cause on 4 found to be improper mounting with vacuum port facing up- moisture ingress and these sensors were 3rd party supplied as well) TPS failures- 2 in aircraft (1 over 20 years old, moisture ingress. Sealed design used for last 10 years) Incidents/ Accidents We've heard of 1 forced landing which was the result of poor wiring by the installer with an injector wire pinched to ground. Same customer, some time before had intermittent engine running, traced to a very scary wiring connection to injector power. One V6 where the user installed an aluminum exhaust system which collapsed under the heat load and melted through the Hall sensor cable. Forced landed in a tomato field. Afterwards, we supplied with fire sleeve over the cables and now have Tefzel cables. One plane limped around the pattern after takeoff on 3 of 4 cylinders with an apparently dead injector (low EGT and CHT indication). Landed safely. Injector was checked extensively, worked fine in testing. ECU changed out and old one sent back. No fault found in old one and it has been running perfectly in our shop car for nearly 4 months now. We suspect a wiring issue in the aircraft as no fault was found with the ECU or other components. I should mention that this aircraft has a brand X ignition system on it, not ours. This one remains a mystery. One fatal accident locally here where I helped the TSB find that the installer had mis-wired circuits to the wrong breaker value. Breaker tripped at about 300 feet AGL, pilot tried to land back on a crossing runway, stall/spin. We've had reports of three, 3rd party ignition drivers attached to our systems which failed from poor/cold solder joints, fortunately all on the ground. Lesson: don't attach 3rd party devices to SDS. We sent new parts to people so they could remove the defective 3rd party components and continue flying safely. At least a dozen reports of rough running/engine shutdowns in flight. Most of these eventually linked to wrong plug wires or non- resistor plugs used or wired contrary to our recommendations. Bad grounds are the #1 cause of odd running issues. Some ECUs have been found wet inside or had flood damage at some point. Third party parts added to our electronics in several cases. All aircraft down safely although probably some soiled underwear in a couple cases. Several ECUs sent back by customers saying they didn't work. Bench tested, installed on test engine here. Worked fine, sent back, customers later found issues with their wiring or installation. Of course, we've had a number of people screw up wiring on installation and fry things, usually when they cut into the harness and make their own connections. Others have programmed things inappropriately, mounted magnets wrong, fuel pumps with reverse polarity, forgot power and ground connections etc. We've had some vexing, weird issues on occasion but have eventually solved almost all of them for our customers. Almost always wiring installations. I can think of two software screwups on release of EM-5 6 cylinder systems. Discovered prior to any engines being run in one case and a rough running issue which was not a safety concern, new boards shipped to our commercial customer. New hardware/ software sent out to 4 affected customers immediately at our expense in the second case. We supplied some components to a vendor about 10 years ago which, through insufficient testing and rushing to meet a deadline, were causing hot running coils COP. Lesson learned, test, test, test and the design is only ready when it's ready. Zero CPI failures in aircraft or automotive usage to date. The bottom line, based on all this experience, is that you're unlikely to suffer a critical electronic failure with our products in your flying career if not modified in some way and are properly installed and operated as we recommend. Of course, not all EFI/EI brands have our record of reliability and some are really quite poor from reports we get from their ex-clients who are replacing other brands with our stuff. We encourage everyone to report their problems so we can see if there is a pattern and develop a fix. I have no problem with people reporting their problems here. We won't cut off support to you. If you've had an issue/ failure with SDS that we haven't resolved, contact me directly or post it here. We don't have anything to hide. We're not perfect but we try to fix anything wrong and make it right. We build on evolutionary improvements which we try to test thoroughly before product release. |
Yeah... and that's why my next electronic ignition will be an SDS product. Gotta like a vendor who says it like it is.
|
Quote:
An enviable track record, for sure. Do these total fleet hours in service include the SDS units "re branded" and sold as their own? |
Ross, where can I download a wiring diagram for the CPI?
|
Quote:
Of course some of these numbers like total flight time are educated estimates. We have hundreds of customers with many hundreds of hours each. The military UAV flight hours are obviously not discussed with us directly but we've heard from someone acquainted with one project saying that a couple of airframes flew over 3000 hours each and we don't know if the ECU was transferred to another engine or the airframe/ engine was lost in use at that point. I should add that the architecture and software is very similar between the aircraft and automotive side so we get feedback/ experience from the vastly larger automotive side where we have many millions of hours of operating hours on our products. |
Quote:
Aero CPI manual is here: http://www.sdsefi.com/cpiaircraftmanrev23.pdf Aero supplement here: http://www.sdsefi.com/cpiaero6x.pdf |
You know folks, there is a huge amount of useful (and some not so useful - you can sort that out...) data in this thread, but very little of it has to do with "PMAG Reliability in 2017". So most of the really good info will be lost because people aren't going to be able to search for it (let's all admit that the search function is pretty basic here), and they won't look under this title to find info on SDS equipment (for instance).
And there is absolutely no way a Moderator can (or will) sort this mess out. Think about that folks - if you have presented good, new information here - think about going and starting a new thread. Or it is all lost for posterity. |
Quote:
"site:vansairforce.com search terms here" Search, don't sort! |
Quote:
Thanks for saying this, Paul. |
Quote:
|
Quote:
How many wires can fail in a Distributed system before it stops producing sparks? |
Quote:
Quote:
Huge thanks to Ross for openly discussing the data! If I ever get the nerve to try another electronic ignition after my scare, it'll be one of his units. |
Quote:
|
Quote:
(No need to answer Bill, we know the answer) |
Quote:
|
Wiring issue primer ?
I have two Pmags and two CPI . This tread has been extremely stimulating. That said, it appears the bottom line issue affecting CPI reliability is wiring termination failures ( ignoring errors ) , i.e. Corrosion, vibration etc. So, perhaps Ross or someone would start a separate thread on optimizing wiring termination from corrosion, vibration, etc ???
|
Quote:
Best practice on wiring tells us to support bundles from movement or physical strain. Done properly, we simply don't see wiring failures at either end. Our old shop car had SDS on it for 19 years and about 5000 hours. Coarse old engine with fair vibration, heavily salted roads in the winter, no particular care in support or strain relief. No wiring breakages or corrosion in that time. The Hall sensor is one piece with the cable, no interim connectors. We just don't see problems here. |
Quote:
|
Quote:
|
Quote:
Mitigation of the hazard is much more productive than relying on a fallback. |
Quote:
Brian, if you personally have a problem with one of your PMAGs, are you going to report that fault on VansAirforce...probably not if it's not in your personal interest to do so. I mean, there's no moral or legal duty of disclosure. I have a LightSpeed Plasma 11 on one side (magneto on the other....I'm with Vic Syracuse on this). I'd have to think very seriously about publicly whinging about a fault in my EI on VansAirforce and then going cap in hand to Klaus at some time in the future for support. ;) I mean, when you buy an EI from a very small, virtually backyard company like EMAG or LightSpeed you're not just buying a product....you're hopping into bed with them for good or for bad. Incidentally I think that the transparency shown by Ross Farnham regarding SDS products in post #88 is just so refreshing. I'm sure his honesty will attract more purchasers to his CPI ignition system. I'm impressed. |
NASA form
Quote:
|
Quote:
|
Quote:
Recall wires can fail open, or shorted. I typically make a list with each wire represented and think about both open and grounded failure modes, ignoring the probability of failure, and initially only considering what happens if it does fail. Example here: http://www.vansairforce.com/communit...8&postcount=63 A wire list for the CPI says shorting or opening almost any pin will shut it down. On the other hand, it does not appear any open or short can make it do strange things. Put another way, it works or it is dead. In the case of the P-mag, the result of an open or short on a few of the wires is obvious. However, I don't know enough about the p-mag to be sure what happens when some of the wires are opened or shorted, notably software driven events. Pin 1: I think you just stated the system works with this one open. If shorted is normal and open doesn't matter, the logical question becomes "Why is it there?" Back up for case ground to engine block? Pins 2 and 3: Without an EIC, an open shifts timing aprox 5 degrees advanced. Field experience says that's probably not critical at WOT with 100LL fuel, just higher CHT. I have no idea what the result might be by shorting either 2 or 3 to ground, with or without the EIC. How does the EIC drive a timing shift with these wires? Pin 4: Obviously a short kills the mag, like any mag. Pin 5: An open above 800 RPM or so is no issue; that's the whole point of the internal generator. What about a short to ground? Pin 6: Tach lead. Assumed to have no effect on the P-mag alone, open or shorted. Does the EIC use the tach signal for anything other than an RPM display? Quote:
|
Quote:
The good news is both ignitions are working. Carl |
Quote:
The point I’m trying to make is that we spend a lot of time on this forum searching for the perfect redundancy scheme, but not nearly enough time executing the basics of the system. Wiring, including connectors, are phenomenally reliable when designed and installed correctly. “Wiring” is significantly more reliable than the components they service, yet we see a lot of electrical issues in the E-AB world. Certainly much more so than in cars or spam cans. The problem, as it turns out, is “us”. Talking about the latest magic scheme/gadget to ensure airliner levels of dispatch reliability may be sexy, but maybe we should spend some time learning how to terminate and route wires first? |
We get the redundancy/ reliability question often in our business during initial emails or phone calls with our customers. Some are wary of total electronic dependency, others are ready to ashcan all the legacy fuel/ ignition bits and step into the new world.
In the end, anything can fail and you're still in a single engined aircraft where the engine itself is a single point a failure. People seem to think that engine is infallibly reliable. It isn't. We all know or have heard of someone who's had one fail mechanically. Well designed electronics are many times more reliable than aircraft engines in my experience since there are no moving or wearing parts (remember our test ECU with 145,000 hours on it). I don't know of a single Lycoming engine which has gone even 1/20th that time without being touched. As someone else posted here, there is always some risk on each flight and everyone has a different level of risk they will accept. Some happily fly single engined at night over the mountains, others would never accept that risk. If you can't accept ANY risk, best to stay home on the ground. We can mitigate many risks by doing good work on our planes and making good decisions on the ground and in the air. |
Anyone out there running one Pmag and one SDS CPI EI?
Are these two devices compatible together on one lycoming engine? If the Pmag failed or misbehaved in flight as described in some posts would it/could it adversely effect the operation of the SDS CPI EI? Anyone else notice that the CEO of SDS participated in this thread? I did. I appreciate hearing from the MFG of products I'm considering. Anyone notice the conspicuous absence of representation from Pmag? Nope, nada, nothing. Just saying. |
Quote:
Quote:
As for what would happen if a break happened in flight, the P-mag only checks for the jumper upon startup, after that it never checks again. So, if you start up on the A memory location, it will continue on that configuration until shutdown. If you have loaded a custom configuration via Emag's EICAD program or our EICommander, you are running off of the B memory location and when running without the EICommander, there is no jumper and when running with the EICommander, you can disconnect it and you will continue to run off of whatever configuration you have loaded, be it the A, B, or a custom configuration. Quote:
Quote:
Quote:
Quote:
As we have seen in this thread, there are many difference of opinion and risk tolerance. All good things. |
Quote:
CEO? We're a small company, I double as the floor sweeper... :) |
Quote:
|
Ross;
In Post #115, you referred to single point reliability. Those failures come in 2 kinds: Instant total failure, and progressive failure. Although modern electronics have a reputation for reliability, they are also perceived to fail utterly and instantly. A Kettering (points) ignition is less reliable, but has a reputation for slowly failing, giving fair warning so it can be repaired before dire consequences. I don't need to heap additional cliche stories, and I have a personal experience where my 1988 Harley electronic ignition module failed softly, I changed it before being stranded. I would be comforted to know that an electronic flight control would have a progressive failure mode. |
Ross
Quote:
Did you get the chance to meet the aforementioned CEO at Reno? Skylor |
Quote:
We'll have some new people coming in to the market which have no previous track record in the field trying to convince you their new whiz bang XXX is the best thing since sliced bread. Only time will tell but usually a perfect controller design does not come on the first iteration. We've seen lots of smart people try and fail. Initial lessons are hard won and only with actual experience doing it. Lab testing is important but the real world is the actual proving ground which defines your success and only time will tell if you did well or not. As a competing manufacturer, we are in a unique position to hear from people using those other products when they fail and come looking for a solution. We hear the good and bad about customer service going along with the failures or problems. We probably never would have developed the CPI if all the other EIs were really good because we'd never get any market share. I could tell you of a conversation with someone using a competing product who had 5 failures in not too many hours and others who've had multiple failures as well. Those people have lost total confidence in those brands obviously. Some stuff we see on other brands, we shake our heads at after seeing the failures. They were very predictable, at least from our experience. We've heard of several high end (expensive) ECUs fail almost regularly in the heat and pounding of the BAJA/ SCORE off road races where SDS just keeps running year after year. One of our clients has over a dozen class wins with the same old SDS ECU. Several competitors running the other brands finally switched over to us and have had no more failures. We were very happy to have one of our clients win the SCCA GT3 championship for the 4th time last month. The auto market gives us a chance to test reliability that doesn't present itself in the aviation environment but there have been spinoffs both ways to improve the products overall. Our reputation for reliability did not come overnight and it did not come without some hard lessons in the earlier days but I'm proud of what our small team has accomplished over 23 years. Hard work but very satisfying. I enjoy going to work every day. We're working to innovate, design new parts to make installation easier on a wider variety of engines, bring customer requested features and ideas into our products and improve them across the board. I've started on a series of videos to help people with installation and use of SDS products-sorry they took so long. I'd like to thank many of our loyal customers who've directly helped us to improve, test and uncover problems during development. We can't think of all these good ideas ourselves! |
| All times are GMT -6. The time now is 12:56 AM. |