---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 12/28/09: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:05 AM - Good website (Keith Burris) 2. 06:51 AM - Tube and Fabric Ground Plane (Jared Yates) 3. 07:53 AM - Re: "engineers" (Speedy11@aol.com) 4. 09:10 AM - Re: Switches (Robert L. Nuckolls, III) 5. 09:35 AM - Re: Re: Switches (Robert L. Nuckolls, III) 6. 09:53 AM - Re: Re: "engineers" (Robert L. Nuckolls, III) 7. 09:57 AM - Re: Good website (Robert L. Nuckolls, III) 8. 10:05 AM - Re: Tube and Fabric Ground Plane (Robert L. Nuckolls, III) 9. 11:41 AM - Slick Start For Sale (Barry) 10. 06:05 PM - Questions: 17-5 & Sizing (Perry, Phil) 11. 07:59 PM - Where is the missing atmospheric carbon dioxide? (RScott) ________________________________ Message 1 _____________________________________ Time: 12:05:24 AM PST US From: "Keith Burris" Subject: AeroElectric-List: Good website Folks; Many of you probably know about these places but some may not. I found the prices to be reasonable. http://www.wiringproducts.com/index.html Also, this place has some interesting products, especially for RVers. The guy who runs it, Rich, is quite easy to work with http://aircraftextras.com/ -- Keith ________________________________ Message 2 _____________________________________ Time: 06:51:43 AM PST US From: "Jared Yates" Subject: AeroElectric-List: Tube and Fabric Ground Plane Dear group, I'm building a Bearhawk and would like to find the best way to mount the ELT antenna, especially regarding the ground plane. I'm using the Ameriking 450 and the whip antenna that came with it. I can use the aluminum wing as a ground plane for the VHF com, but I was thinking that it would be better to keep the ELT antenna on the fuselage. This would allow me to reduce the length of the wire run and thus reduce the chances of crash damage. It would also allow me to provide enough distance between the com and ELT to prevent resonance on the emergency frequency. Some builders have mounted the antenna inside of the 4130 tube fuselage, which has the best crash resistance; but, I would think that the fuselage would be a great faraday cage and would thus limit the transmission considerably. For these reasons I'd prefer to mount the antenna on the top of the fuselage behind the cabin. In this particular fuselage there are non-structural stringers that protrude about 3 inches above the primary structure, so I was planning to make a bracket to use as a mount for the antenna. The bracket would be shaped like an upside down U with the top of the bracket even with the top of the stringers, so that the antenna would attach at the top of the bracket and the bottom legs would be welded to either side of a crossing tube. How should I provide for a ground plane? The stringers are aluminum and about 12 inches apart, and the steel fuselage is about 3" below the base of the antenna. Would it be a good idea to use either of those as part or all of the ground plane, or would it be better to make something out of copper foil and try to insulate that ground plane from the airframe parts? Any thoughts? Here's a picture of how the fuselage is built: http://jaredyates.com/temp/groundplane.jpg Thanks ________________________________ Message 3 _____________________________________ Time: 07:53:39 AM PST US From: Speedy11@aol.com Subject: AeroElectric-List: Re: "engineers" So, Ralph. It's okay for you to post unrelated remarks, but now (because you said so) nobody else should respond. Hmmm ... you got your shot in, but nobody can counter. I suggest responding with "do not archive" is more appropriate. In fact, such an addition may have been appropriate for your posting. Stan Sutterfield Do not archive OK, this is not the correct venue to discuss this sort of thing. I'm the biggest complainer of abuse of this email list and now I'm guilty. Please don't reply to the list about this thread...if you want to continue we'll find another venue. ________________________________ Message 4 _____________________________________ Time: 09:10:24 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Switches At 06:01 PM 12/27/2009, you wrote: > >Thanks Bob; I guess I knew but forgot the points you made, should have known >better. I see what I want around but it's made for heavy iron and cost like >it also. Yeah. I've participated in the design of a number of specialized cockpit controls for things like gear, flaps, spoilers, etc. In addition to their unique form and fit requirements to comply with design goals for cockpit decorum, they often included a variety of position sensors with redundancy to preclude un-commanded motions, etc. I think the last flap control handle project I saw produced a device that sold to the OEM for about $2,000! Here in the OBAM aircraft world, we can do a lot to dress up plain vanilla controls. But the Big Guys do it too. The gear and flap switches in a Bonanza are Honeywell toggle switches with added window dressing. Bob . . . //// (o o) ===========o00o=(_)=o00o======== < Go ahead, make my day . . . > < show me where I'm wrong. > ================================ ________________________________ Message 5 _____________________________________ Time: 09:35:10 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Switches At 06:57 PM 12/27/2009, you wrote: OK! Shot down by the master! I respect Bob's arguments; however, I do not consider a $20 Mil-Spec switch to be a super-part. Certainly we can use commercial grade switches in our homebuilt aircraft, but it is still prudent to insure that the switches have undergone some reliability testing and have current and voltage ratings appropriate for their intended use. Certification by a nationally recognized testing agency such as Underwriters Laboratories may add to the switches cost a bit, but the rating confirms that required overload and endurance testing have been successfully completed. Are we shooting at each other or trying to achieve a shared understanding? How does one conduct such pre-purchase studies? I'm fairly certain that every manufacturer did some pre-production proof of design testing to insure compliance with their own design goals. But few if any have published reports on such studies unless they're attempting to compete with other manufacturers where the rules of the game call out Mil-Spec, SAE, ISO, UL, etc. etc. I'll suggest that there are many sources of switches suited to our tasks that offer no published test data. Further, when data is available, it was not gathered by the same test protocols as competing products. I went through this exercise 20+ years ago on the GP-180 program at Gates-Learjet. Attempts to evaluate 6 different brands of interchangeable basic switches based on their published data proved impossible. But in fact, every device being considered would have been just fine for our application. I would invite you to review a paper I wrote some years ago about switch ratings at: http://www.aeroelectric.com/articles/Switch_Ratings.pdf Switch "ratings" are not a common language among all manufacturers of switches . . . else there would not be so many ratings standards by which the folks who write rules for aforementioned games can choose. Further, the ratings games are crafted with the revenue generating applications (down time on a $high$ machine costs many times more than the value of the switch), safety issues in both industrial and military hardware (switch failure increases risk of injury or death). In the OBAM aircraft environment, we assume risks of for lack of knowledge and craftsmanship that are generally considered to be very low numbers in the commercial, industrial and military worlds. Hence my vociferous suggestions that we place failure tolerance above all other considerations for the design, operation and maintenance of our airplanes. A search of the accident archives reveals that failures of electrical system components in light aircraft account for a tiny proportion of causation for the accident. In those situations where electrical failures were prominent players, it was easy to deduce in hindsight how that stack-up of events could have been comfortably managed by the failure tolerant aircraft flown by a knowledgeable pilot. I don't recall reading ANY accident analysis where failure of a component to perform as advertised was a contributing factor. No doubt there are SOME such reports but I've not found one yet. It's been my suggestion for years of participation first on Compuserve AVSIG and later here on the Matronics Lists that we can design, fabricate and operate airplanes using the most ordinary components and still enjoy very low risk use of the airplane's electrical system. This is especially true of machines that get on average, 50 hours of service per year as opposed to machines that run 1000's of hours per year. Bob . . . ________________________________ Message 6 _____________________________________ Time: 09:53:12 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: "engineers" OK, this is not the correct venue to discuss this sort of thing. I'm the biggest complainer of abuse of this email list and now I'm guilty. Please don't reply to the list about this thread...if you want to continue we'll find another venue . . . Is this not a venue for the exchange of simple-ideas and their incorporation into recipes for success? When an idea/recipe is offered, is it not useful to gage potential quality of the idea against the demonstrated history of the offerer? While few of us here on the List have credentials framed on our walls, we ALL have experiences and talents that qualify us as teachers. Depending on the sum total of life experiences and demonstrated achievements, some of us have more to offer than others. But no combination of simple-ideas into any recipe for success becomes less valuable just because the offerer "is not qualified" based on some arbitrary standard. An argument was proposed that lack of recognized credential placed the value of ideas or the integrity/motivations of some offerers in doubt. I'll suggest that comparative study of demonstrable achievement versus credential-based stature in this community is useful to the goals of this List. Bob . . . ________________________________ Message 7 _____________________________________ Time: 09:57:25 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Good website At 02:03 AM 12/28/2009, you wrote: >Folks; >Many of you probably know about these places but some may not. I >found the prices to be reasonable. > >http://www.wiringproducts.com/index.html An impressive site . . . with caution. Terminals offered are not PIDG style and there are good reasons to avoid glass cartridge fuses. No doubt there are numerous products offered that are useful to the OBAM aircraft builder but if in doubt, ask about a product being considered here on the List first . . . Bob . . . ________________________________ Message 8 _____________________________________ Time: 10:05:52 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Tube and Fabric Ground Plane At 08:31 AM 12/28/2009, you wrote: > > >Some builders have mounted the antenna inside of the 4130 tube fuselage, >which has the best crash resistance; but, I would think that the fuselage >would be a great faraday cage and would thus limit the transmission >considerably. Yes. Don't do this . . . >For these reasons I'd prefer to mount the antenna on the top of the fuselage >behind the cabin. In this particular fuselage there are non-structural >stringers that protrude about 3 inches above the primary structure, so I was >planning to make a bracket to use as a mount for the antenna. The bracket >would be shaped like an upside down U with the top of the bracket even with >the top of the stringers, so that the antenna would attach at the top of the >bracket and the bottom legs would be welded to either side of a crossing >tube. How should I provide for a ground plane? Make sure you have good electrical connection to the bracket that is welded to the tube. This can be accomplished by mate up pressures of attaching hardware even when intermediate layers include insulating materials. > The stringers are aluminum >and about 12 inches apart, and the steel fuselage is about 3" below the base >of the antenna. Would it be a good idea to use either of those as part or >all of the ground plane, or would it be better to make something out of >copper foil and try to insulate that ground plane from the airframe parts? >Any thoughts? Foil ground plane strips on the inside of the fabric would be useful but probably wouldn't increase performance greatly. The BIG design problem is one of mechanical robustness. Getting your antenna mounted to solid structure through your proposed bracket will go a long way toward a low maintenance and adequately performing system. Of course the feedline shield needs to get a good electrical connnection to the same bracket. Bob . . . ________________________________ Message 9 _____________________________________ Time: 11:41:54 AM PST US Subject: AeroElectric-List: Slick Start For Sale From: "Barry" Slick Start p/n SS1001 removed at 160hr total time in good working condition to install elecrtonic ignition. I have the installation instructions, STC info and yellow tag return to service. $295.00 with shipping included. Contact me direct. Do not archive. Thanks Barry blalmarz@embarqmail.com 239-567-2271 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=279012#279012 ________________________________ Message 10 ____________________________________ Time: 06:05:41 PM PST US Subject: AeroElectric-List: Questions: 17-5 & Sizing From: "Perry, Phil" Hi, I've been a lurker for awhile, mainly because I haven't had to think too much about the electrical system of the airplane yet. There is no doubt that I'll be covering some well plowed ground with these questions, but maybe you can help get me off high-center. I am building an all glass RV-10 and I don't plan on using Electronic Ignition. My first question involves figure 17-5 (Dual Alternator, Dual Battery Electrical System). The narrative discussion on the crossfeed contactor is a little light and I'm having a hard time getting a handle on that diagram. 1) I'd like to understand how the cross feed functions. a. Is it an automatic switch? b. Is it closed during normal operations? c. I'm guessing it's just like any other contactor and requires ~1 Amp current to maintain closure? 2) Still on 17-5, couldn't there be a diode placed between the "Main Battery" and the "Main Bus"? For the cost of a diode, you could add a secondary path that is independent of any contactor. The chances of needing to use it is highly unlikely, but it's a really cheap way to save 2-3 Amps (Main Bat Contactor, Aux Bat Contactor, Cross Feed Contactor) if you ever need to shed off load. 3) Finally I'm not finding much in the way component sizing. Meaning I'm trying to figure out which specific diodes I will need. Which specific model numbers/sizes of contactors I will need. Thanks for the help. As I get the architecture laid out, I'll share it for review. Thanks, Phil ________________________________ Message 11 ____________________________________ Time: 07:59:07 PM PST US From: RScott Subject: AeroElectric-List: Where is the missing atmospheric carbon dioxide? The models say it should be there, but it's not! We've gotta find it--our models are right, because they all agree! http://www.reuters.com/article/idUSTRE50S6CW20090129 http://www.icsu-visioning.org/2009/07/where-is-the-missing-atmospheric-carbon-dioxide/ Oh, but the way, the satellite failed--I don't know if the missile crashed or if the satellite just didn't work. 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