---------------------------------------------------------- JabiruEngine-List Digest Archive --- Total Messages Posted Sat 12/09/06: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:19 AM - Re: Re: Jabiru Starter contactor and solenoid (Grant Piper) 2. 07:07 AM - Re: Re: Jabiru Starter contactor and solenoid (Gilles Thesee) 3. 07:42 AM - Re: Jabiru Starter contactor and solenoid (Gilles Thesee) 4. 09:30 AM - Re: Jabiru Starter contactor and solenoid (Paul Mulwitz) ________________________________ Message 1 _____________________________________ Time: 03:19:26 AM PST US From: "Grant Piper" Subject: Re: JabiruEngine-List: Re: Jabiru Starter contactor and solenoid I'm a late starter to this topic, but I applaud Doug's pleas to keep it simple. Less things, less to go wrong. My RV-4 with Lyc has a Datsun alternator, Odyssey battery and no lights or gyros at all. It is legal at that. I do use a Master relay, but eliminated the separate starter relay when I saw that my starter had a piggyback relay as per a car. Yes, my starter cable is 'live' all the time the Master is on, but if I have a short I can isolate it by switching the Master off. Yes, I will lose all power, but it is a VFR aircraft so that isn't a biggie. Keep it simple, spend the dollars saved on avgas, and go flying this year instead of the next. Grant Piper RV-4 VH-PIO 260hrs. SAAA (TC) ----- Original Message ----- From: Kayberg@aol.com To: jabiruengine-list@matronics.com Sent: Saturday, December 09, 2006 10:27 AM Subject: Re: JabiruEngine-List: Re: Jabiru Starter contactor and solenoid I suppose I should keep my mouth shut, but in case there are other folks who are daunted by the diagram Modified Z-16, I want to affirm your desire for simplicity. I am impressed by the efforts of Vozzen and Rico. I dont mind the efforts of electical engineers to plan for every possible failure mode. I understand that some experimental aircraft builders want to build an electrical system to rival any of the General Aviation fleet. But there is another strategy. If you are careful about the avionics you purchase, use some common sense and dont install a comprehensive lighting system ( how badly do you want to crash at night? .... if you dont have lights you wont be tempted..) and are willing to just read your own voltmeter, you can have a simple system that can be installed in a few hours instead of a few months. It is ok to use a couple toggle switches for your ignition kills. It is ok to just run breaker switches or switch and fuse to a couple radios. If you keep your electical loads down, then you dont need much of an alternator. As you may know, if you have too big a load on the Jabiru alternator, you can crispy the stator. You can add another seperate alternator, but why would you want to? The notion of a solonoid operated by a master switch sounds good, but if the wire or coil in it goes south, so does your electrical power. That may balance the possiblity of shorting the big wire to the starter solonoid. If you are building a small, high performance bird like a Sonex and want to make it IFR, by all means design and build as complicated an electrical system as possible. May I suggest autopilot, a Garmin radio stack, electrical gyros and a seat warmer? The extra time it takes to build all that will prolong your life just that much longer. I am just saying that IN MY OPINION, it is perfectly OK to only have a couple circuits. One for the start, one for the radios and one for a couple other small things. If you are a bit paranoid, then include a switch in the charging circuit so you can shut off the alternator power to the battery if your volt meter gets too high. Hook the power circuits to the post on the starter solonoid that the big battery cable goes to...just so it is easier to disconnect the battery. It is true that if the solonoid sticks, you will have some drama while the starter twirls the engine until the battery dies...but when is the last time your car did that to you? It is wired the same way. Just buy a new start solonoid every 500 hours or so. That should preclude the arcing from dirt. Ok, so let the reactions begin. I'm sure I deserve to be flamed. Doug Koenigsberg ________________________________ Message 2 _____________________________________ Time: 07:07:03 AM PST US From: Gilles Thesee Subject: Re: JabiruEngine-List: Re: Jabiru Starter contactor and solenoid Grant, > Yes, my starter cable is 'live' all the time the Master is on, but > if I have a short I can isolate it by switching the Master off. Yes, > I will lose all power, but it is a VFR aircraft so that isn't a biggie. Correct. This is how any aircraft should be wired. > > Keep it simple, spend the dollars saved on avgas, and go flying this > year instead of the next. Perfectly right. The problem is, some builders confuse 'simple' with over simplistic, or try to take short cuts on safety by 'simplifying' the thinking process before building. For those who think the electrical circuit is worth some consideration, a visit to http://www.aeroelectric.com will prove very informative. Regards, Gilles Thesee Grenoble, France http://contrails.free.fr ________________________________ Message 3 _____________________________________ Time: 07:42:52 AM PST US From: Gilles Thesee Subject: Re: JabiruEngine-List: Jabiru Starter contactor and solenoid Hi Doug, > I am the proud USA importer of the French kit airplane, the Sky Ranger! Yes everyone here knows the Sky Ranger. > Ranger and a 3300 in a Lightning. > > I just run the large power wire about 6" to the starter solenoid. I > would attached fused or breaker protected circuits from the post there > to elsewhere. If one of them were to short, I would expect protection > to kick in or if it shorted on the way to the breaker, I would expect > the wire to just fry without much damage. The runs are short and the > firewall penetration carefully protected. If complexity (and maybe weight) is a consideration, why use breakers at all ? Fuses would just do, with lower cost, installation complexity and weight. > > I note that the same large 6" wire would go to the master solenoid and > then another 6" wire would to to the Jab start solenoid. No real > difference in protection for the large wire. In either case it has a > 6" unprotected run. The battery contactor is to be located as close to it's battery as physically possible. The role isn't to protect wires (they are large, and won't fry), but to disconnect the ship's circuit from any source of electricity. If the component are close together, you may consider a metal strap instead of a wire. Still simpler. > But if the master solenoid, which must be continously held in place > by current were to experience low voltage, coil failure, switch > failure or a wire break then all power would be lost......unless one > has a backup circuit that bypasses the master....which is the > situation I began at. The goal of the electrical circuit designer is to minimise the fire and fault hazard. The only way to experience low voltage is low battery and/or faulty charging circuit. The engine is not electrically dependent, and I suppose that in the USA, ultralights only fly day VFR ? No critical circuit to keep running. So why take shortcuts on safety for fear of lacking of electricity ? > I understand that popular aviation thought is in love with the master > solenoid, but I am wondering if it adds complexity and vulnerability > to solve an unlikely problem...on very simple light airplanes. Simplicity should be in the aircraft, not in the designer/builder efforts in design. It takes much thinking to design a really simple and reliable aircraft system. Popular aviation would really benefit from carefully engineered and crafted systems : I recently had to troubleshoot a poorly wired ultralight (not a Sky). Really poor craftsmanship from the importer... > I like them more on GA airplanes with their 60 -100 amp circuits with > retractable gear, lights, dog polishers and window foggers. ;-))) > > ..... Of course a short can cause a fire but there must be > combustables nearby and the insulation must be combustable. Otherwise > a brief arc, a brief smell and it is all over. Yeah, that's what is often experienced in ultralights. Sparcs and arcs, and flat batteries. Auto PVC spaghetti wire everywhere, control cables and rods rubbing against structure (yes sir, even on Sky Rangers) The reputation of sloppy craftsmanship is unfortunately sometimes deserved... If I happened to buy an aircraft and experienced even the briefest of arc ans smell, I'd have some 'interesting' discussion with the seller... > > If a starter solenoid actually stuck, it will just keep turning the > engine untill the battery power is drained or the starter melts > down. While disconcerting, it would happen on the ground and be over > quickly. No so if your master solenoid craps out in the air. You > lose radios, EIS, intercom, flaps and whatever else you power. You really would shed circuit protection and good wiring practice just for fear of losing flaps when turning the master off ? Would no flaps on a Sky Ranger really be a problem ? BTW, in a car, you also lose many thing when turning the keyswitch off. Have you considered subscribing to the Aeroelectric List on Matronics ? Much interesting matters, and opportunity to discuss electrical options much more in-depth Best regards, Gilles http://contrails.free.fr ________________________________ Message 4 _____________________________________ Time: 09:30:10 AM PST US From: Paul Mulwitz Subject: Re: JabiruEngine-List: Jabiru Starter contactor and solenoid Hi Gilles, The new Light Sport Airplane rule in the USA allows for either day/VFR or Night and/or IFR operations. Of course, there are extra equipment requirements for night or IFR operations. It is the Sport Pilot rule that limits pilots (rather than aircraft) to day/VFR operations. The much older "Ultralight" in the USA is not worthy of any serious flight including daytime. I don't think anyone would consider flying one of those "Flying lawn chairs" at night. Those "Ultralights" are limited to one seat, 5 gallons of fuel, maximum empty weight of 254 pounds, and a maximum cruise speed around 60 mph. I have been following your discussion of the need for the master contactor on an airplane. I remain unconvinced either way about the need for this device. It is relatively clear it can be used to deal with in-flight fires, and it also might be used to make sure all equipment is really off when the plane is finished for the day. If there is a switch installed on the battery circuit for all devices except the starter, then normal sized wiring and switch could be used. This approach would use a solenoid for the starter connected in parallel to the battery. The only obvious risk with this approach is that the starter solenoid gets stuck or activated without the pilot's desire. This seems unlikely and un-harmful even if it does occur. Perhaps I am missing something important. It seems that the expense in cost, weight, and electrical load imposed by the master contactor is only there to deal with the unlikely problem of a run-away starter solenoid. Paul Zodiac XL builder - nearing completion of fuselage >I suppose that in the USA, ultralights only fly day VFR ? ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message jabiruengine-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/JabiruEngine-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/jabiruengine-list Browse Digests http://www.matronics.com/digest/jabiruengine-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.