---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 07/16/11: 18 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:42 AM - Re: ELT antenna placement (Jared Yates) 2. 02:49 AM - Re: It's nice when the center holds . . . (Peter Pengilly) 3. 04:10 AM - ELT antenna placement () 4. 05:13 AM - Re: ELT antenna placement (Dave Saylor) 5. 07:21 AM - Re: It's nice when the center holds . . . (Larry Mac Donald) 6. 07:30 AM - Re: ELT antenna placement (Kelly McMullen) 7. 07:39 AM - Re: It's nice when the center holds . . . (Robert L. Nuckolls, III) 8. 07:54 AM - Re: ELT antenna placement (Robert L. Nuckolls, III) 9. 08:19 AM - Re: ELT antenna placement (Robert L. Nuckolls, III) 10. 08:49 AM - ELT antenna placement (BobsV35B@aol.com) 11. 11:13 AM - Re: Re: Viking Engine (Ed Gilroy) 12. 03:02 PM - Re: It's nice when the center holds . . . (Peter Pengilly) 13. 04:00 PM - Re: It's nice when the center holds . . . (Dave Saylor) 14. 04:13 PM - Re: It's nice when the center holds . . . (Neal George) 15. 05:06 PM - Re: ELT antenna placement (Kelly McMullen) 16. 06:51 PM - Re: ELT antenna placement (Paul Kuntz) 17. 07:44 PM - Electrical System Drawing (Paul Zimmer) 18. 07:50 PM - Electrical System Drawing (Paul Zimmer) ________________________________ Message 1 _____________________________________ Time: 01:42:09 AM PST US Subject: Re: AeroElectric-List: ELT antenna placement From: Jared Yates In one prior case, we had an airplane that was transmitting ground control v oice (121.9) over 121.5. We attributed it to resonance on the elt antenna, w hich was in a non standard location for that type, closer than normal to the vhf com. After moving the elt antenna back a couple of feet the bleed over stopped. This type of problem might be something to consider in your decis ion. On Jul 16, 2011, at 1:28, Paul Kuntz wrote: > I'm installing a 121.5/406 MHz ELT in my homebuilt project. The installat ion instructions tell me to put the ELT whip antenna at least 3 feet from my VHF radio antenna. Is this really necessary? There is the possibility of m anually activating the ELT in the air in the event of an emergency, while co ntinuing to communicate with the VHF radio, but I'm thinking that the more l ikely scenarios will be to operate one or the other, but not both. That is, the ELT becomes a factor only in the case of a true emergency, in which cas e I would first squawk emergency and communicate the situation by VHF voice ( flying the airplane first, of course). Then, activate the ELT (one button p ress) if a forced landing appears inevitable, but I'm probably done talking o n the radio at that point. > > Is the concern simply the presence of another vertically oriented conducto r in relatively close proximity to the antenna in use, thus influencing its p erformance? Even if both the ELT and the VHF radio are active at the same t ime, is 3 ft of separation important? > > At any rate, it would be more convenient from an installation perspective t o put them closer together. Any advice? > > Thanks, > Paul Kuntz > > ========================== ========= ========================== ========= ========================== ========= ========================== ========= > ________________________________ Message 2 _____________________________________ Time: 02:49:49 AM PST US From: Peter Pengilly Subject: Re: AeroElectric-List: It's nice when the center holds . . . Bob, I don't know F-16 systems, but have experience of other single seat military aircraft. I'm guessing the Hydrazine unit is a light weight method of mitigating the hazard of providing power once the (single) motor has stopped, without fitting a huge battery. Most combat aircraft are started with a ground power unit, so the battery doesn't have to be very big. I'm guessing the electrical demands of an F-16 are quite large (fly-by-wire), even with load shedding, so a huge battery would be required to get the airplane to the ground from max altitude - or a reasonably powerful (heavy) gas turbine APU. So a one shot hydrazine based system is a reasonable (light weight) solution, although it has a maintenance overhead. Bear in mind the F-16 was designed as a lightweight fighter, so weight saving was probably quite high on the priority list. Peter On 15/07/2011 22:47, Robert L. Nuckolls, III wrote: >> >> >> What is really dead is the power source! >> > > The last few words of the pilot suggested something I'd > not heard before. He talked about a 'hydrazine' hazard > around his aircraft as he was talking with locals at > his airport of destination. There was also a reference > to an "EPU" . . . 'possible emergency power unit'. > > Hydrazine and sulfuric acid combine in a manner that > provides spontaneous combustion with a very energetic > release of energy. In this case, I'm thinking that the > airplane was fitted with what could be a compact > and relatively light weight energy source that required > very little maintenance and has a long storage life. > (I've seen AQM-37 hydrazine powered targets successfully > flown after 20 years in storage). > > It would be interesting to hear from folks with experience > inside the operating world of this style of aircraft > as to it's 'dead stick' options for power. > > Bob . . . > > * > > > * ________________________________ Message 3 _____________________________________ Time: 04:10:10 AM PST US From: Subject: AeroElectric-List: ELT antenna placement 7/16/2011 Hello Paul, You wrote: "Is this really necessary?" After 6 years plus of construction and many hours of preparation for the first flight in my KIS TR-1 experimental amateur built aircraft I was unable to taxi out of the apron area because every time I keyed my number one VHF com radio to request taxi clearance from ground control the ELT transmitter was activated -- very frustrating. The problem was caused by proximity and orientation of the antennas of the two devices. I eventually relocated the ELT antenna -- problem solved. OC PS for Bruce: Knowledge of 14 CFR 91.207 (f) (4) permitted me to disable the ELT and complete the first flight as plannned. ================================================================ Time: 10:33:48 PM PST US Subject: AeroElectric-List: ELT antenna placement From: Paul Kuntz I'm installing a 121.5/406 MHz ELT in my homebuilt project. The installation instructions tell me to put the ELT whip antenna at least 3 feet from my VHF radio antenna. Is this really necessary? There is the possibility of manually activating the ELT in the air in the event of an emergency, while continuing to communicate with the VHF radio, but I'm thinking that the more likely scenarios will be to operate one or the other, but not both. That is, the ELT becomes a factor only in the case of a true emergency, in which case I would first squawk emergency and communicate the situation by VHF voice (flying the airplane first, of course). Then, activate the ELT (one button press) if a forced landing appears inevitable, but I'm probably done talking on the radio at that point. Is the concern simply the presence of another vertically oriented conductor in relatively close proximity to the antenna in use, thus influencing its performance? Even if both the ELT and the VHF radio are active at the same time, is 3 ft of separation important? At any rate, it would be more convenient from an installation perspective to put them closer together. Any advice? Thanks, Paul Kuntz ________________________________ Message 4 _____________________________________ Time: 05:13:52 AM PST US From: Dave Saylor Subject: Re: AeroElectric-List: ELT antenna placement I agree, I've seen comm radios set of a nearby ELT on several occasions. It's not uncommon at all. I'd keep those antennas away from each other. Dave Saylor AirCrafters 140 Aviation Way Watsonville, CA 95076 831-722-9141 Shop 831-750-0284 Cell On Sat, Jul 16, 2011 at 4:06 AM, wrote: > > 7/16/2011 > > Hello Paul, You wrote: "Is this really necessary?" > > After 6 years plus of construction and many hours of preparation for the > first flight in my KIS TR-1 experimental amateur built aircraft I was unable > to taxi out of the apron area because every time I keyed my number one VHF > com radio to request taxi clearance from ground control the ELT transmitter > was activated -- very frustrating. > > The problem was caused by proximity and orientation of the antennas of the > two devices. I eventually relocated the ELT antenna -- problem solved. > > OC > > PS for Bruce: Knowledge of 14 CFR 91.207 (f) (4) permitted me to disable the > ELT and complete the first flight as plannned. > > ================================================================ > > Time: 10:33:48 PM PST US > Subject: AeroElectric-List: ELT antenna placement > From: Paul Kuntz > > I'm installing a 121.5/406 MHz ELT in my homebuilt project. The > installation instructions tell me to put the ELT whip antenna at least 3 > feet from my VHF radio antenna. Is this really necessary? There is the > possibility of manually activating the ELT in the air in the event of an > emergency, while continuing to communicate with the VHF radio, but I'm > thinking that the more likely scenarios will be to operate one or the other, > but not both. That is, the ELT becomes a factor only in the case of a true > emergency, in which case I would first squawk emergency and communicate the > situation by VHF voice (flying the airplane first, of course). Then, > activate the ELT (one button press) if a forced landing appears inevitable, > but I'm probably done talking on the radio at that point. > > Is the concern simply the presence of another vertically oriented conductor > in relatively close proximity to the antenna in use, thus influencing its > performance? Even if both the ELT and the VHF radio are active at the same > time, is 3 ft of separation important? > > At any rate, it would be more convenient from an installation perspective to > put them closer together. Any advice? > > Thanks, > Paul Kuntz > > ________________________________ Message 5 _____________________________________ Time: 07:21:51 AM PST US From: Larry Mac Donald Subject: Re: AeroElectric-List: It's nice when the center holds . . . Carlos, I'll take a shot at that. Back in the days of yore airplanes were slower and if you lost your engine your control surfaces, on some airplanes, w ere sluggish at best. This made the stick somewhat unresponsive. So some one said "it's a dead stick" Just one of those things that stuck in our lexicon. Another such example was told to us, my Aeronautics ground scho ol, by our instructor. He had worked for the first air mail service. He, and the rest of his team hosted a british aviator and as they were doin g they're flying and lying the britisher mentioned the word altimeter. W ell, up to that point we called the instrument an al-ta-meter. The briti sh gentleman called it an al-tim-meter. The boys of the first air mail s ervice thought that his way of saying it was more like the way it should be said. And it stuck, world wide. Things just happen that way. Larry On Jul 15, 2011, at 2:55 PM, Carlos Trigo wrote: > Nice landing, and a very good demonstration of excellent pilot skills! > > The only thing I don=92t really understand is why you (native English speakers) call this situation a =93Dead Stick=94 landing, when this is e verything but a dead stick. On the contrary, this is a very =93Alive sti ck=94 situation=85. > What is really dead is the power source! > > Carlos Trigo > > > > -----Original Message----- > > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aer oelectric-list- > > server@matronics.com] On Behalf Of Robert L. Nuckolls, III > > Sent: sexta-feira, 15 de Julho de 2011 18:40 > > To: aeroelectric-list@matronics.com > > Subject: AeroElectric-List: It's nice when the center holds . . . > > > > > > > > See: > > > > http://www.patricksaviation.com/videos/SUPERGT/3384/ > > > > > > Bob . . . > > //// > > (o o) > > ======================== ============ ======================== ============ ======================== ============ ======================== ============ > ____________________________________________________________ Penny Stock Jumping 3000% Sign up to the #1 voted penny stock newsletter for free today! http://thirdpartyoffers.juno.com/TGL3141/4e219d9dda3df2f1c1st06vuc ________________________________ Message 6 _____________________________________ Time: 07:30:16 AM PST US From: Kelly McMullen Subject: Re: AeroElectric-List: ELT antenna placement Another risk is that many ELT transmitters are poorly shielded from strong adjacent RF. Flying near a TV or FM transmitter antenna can cause the oscillator of the ELT transmitter to radiate harmonics, which then are picked up by your com radio, breaking squelch and causing poor reception. My plane used to suffer from this syndrome until I moved one of the VHF antennas to the belly. On 7/16/2011 5:10 AM, Dave Saylor wrote: > --> AeroElectric-List message posted by: Dave Saylor > > I agree, I've seen comm radios set of a nearby ELT on several > occasions. It's not uncommon at all. > > I'd keep those antennas away from each other. > > Dave Saylor > AirCrafters > 140 Aviation Way > Watsonville, CA 95076 > 831-722-9141 Shop > 831-750-0284 Cell > > > On Sat, Jul 16, 2011 at 4:06 AM, wrote: >> --> AeroElectric-List message posted by: >> >> 7/16/2011 >> >> Hello Paul, You wrote: "Is this really necessary?" >> >> After 6 years plus of construction and many hours of preparation for the >> first flight in my KIS TR-1 experimental amateur built aircraft I was unable >> to taxi out of the apron area because every time I keyed my number one VHF >> com radio to request taxi clearance from ground control the ELT transmitter >> was activated -- very frustrating. >> >> The problem was caused by proximity and orientation of the antennas of the >> two devices. I eventually relocated the ELT antenna -- problem solved. >> >> OC >> >> PS for Bruce: Knowledge of 14 CFR 91.207 (f) (4) permitted me to disable the >> ELT and complete the first flight as plannned. >> >> ================================================================ >> >> Time: 10:33:48 PM PST US >> Subject: AeroElectric-List: ELT antenna placement >> From: Paul Kuntz >> >> I'm installing a 121.5/406 MHz ELT in my homebuilt project. The >> installation instructions tell me to put the ELT whip antenna at least 3 >> feet from my VHF radio antenna. Is this really necessary? There is the >> possibility of manually activating the ELT in the air in the event of an >> emergency, while continuing to communicate with the VHF radio, but I'm >> thinking that the more likely scenarios will be to operate one or the other, >> but not both. That is, the ELT becomes a factor only in the case of a true >> emergency, in which case I would first squawk emergency and communicate the >> situation by VHF voice (flying the airplane first, of course). Then, >> activate the ELT (one button press) if a forced landing appears inevitable, >> but I'm probably done talking on the radio at that point. >> >> Is the concern simply the presence of another vertically oriented conductor >> in relatively close proximity to the antenna in use, thus influencing its >> performance? Even if both the ELT and the VHF radio are active at the same >> time, is 3 ft of separation important? >> >> At any rate, it would be more convenient from an installation perspective to >> put them closer together. Any advice? >> >> Thanks, >> Paul Kuntz >> >> >> >> >> >> >> > > ________________________________ Message 7 _____________________________________ Time: 07:39:41 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: It's nice when the center holds . . . At 04:46 AM 7/16/2011, you wrote: >Bob, > >I don't know F-16 systems, but have experience of other single seat >military aircraft. I'm guessing the Hydrazine unit is a light weight >method of mitigating the hazard of providing power once the (single) >motor has stopped, without fitting a huge battery. Most combat >aircraft are started with a ground power unit, so the battery >doesn't have to be very big. I'm guessing the electrical demands of >an F-16 are quite large (fly-by-wire), even with load shedding, so a >huge battery would be required to get the airplane to the ground >from max altitude - or a reasonably powerful (heavy) gas turbine >APU. So a one shot hydrazine based system is a reasonable (light >weight) solution, although it has a maintenance overhead. Bear in >mind the F-16 was designed as a lightweight fighter, so weight >saving was probably quite high on the priority list. That's about what I would have guessed. Some years ago, there was some work described in the development of tiny, combustion driven turbines for hi-energy stand-by sources. One author even hypothesized a lap-top computer running on butane. Haven't heard/read anything along those lines since. The GAR series IR guided missiles I used to work on at Hughes-Tucson had a little bottle of nitrogen held in liquid state at room temperatures . . . man, that was a lot of pressure! A frangible diaphragm held the liquid in check until launch. Then for the 90-second or so service life of the missile, the liquid expanded to run a small PM alternator that produced 150 watts to power electronics. It was then routed to the back of the IR optics to keep the lens cool at Lots-a-Mach. After that, it pressurized an open loop hydraulic system that operated flight controls at the trailing edges of the guidance fins before being exhausted overboard. That was in 1960. Given the advances in really tiny gas turbines, it seems certainly possible and perhaps practical to craft a light weight power generation device with considerable output and endurance while using up much less volume and weight budget needed for batteries of the same capability. Some ideas take a very long time to evolve into useful product . . . Bob . . . ________________________________ Message 8 _____________________________________ Time: 07:54:25 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: ELT antenna placement At 07:10 AM 7/16/2011, you wrote: Saylor I agree, I've seen comm radios set of a nearby ELT on several occasions. It's not uncommon at all. I'd keep those antennas away from each other. It would appear to be the only option. It may be very $difficult$ to fix what appears to be a design bug internal to the ELT. The earliest ELT's used a spring-loaded mass to close an activation switch in response to g-forces of a crash. No doubt modern ELTs use the solid-state acceleration sensors for this task . . . which produce VERY tiny signals requiring a lot of circuit gain. This type of circuitry offers a high risk of vulnerability to RF interference. This may be an area where qualification of the device to standard DO-160 (good for part 23) stresses was insufficient to stand off the extra-ordinary vulnerabilities of these kinds of circuits. A lot of hardware we did for the military and for Part-25 and up applications was exposed to really nasty RF radiation . . . 200 volts/meter or more . . . during qualification. No doubt this extra step in qualification would have exposed vulnerabilities that are now plaguing customers. > Paul wrote: > I'm installing a 121.5/406 MHz ELT in my homebuilt project. The > installation instructions tell me to put the ELT whip antenna at least 3 > feet from my VHF radio antenna. Is this really necessary? There is the > possibility of manually activating the ELT in the air in the event of an > emergency, while continuing to communicate with the VHF radio, but I'm > thinking that the more likely scenarios will be to operate one or the other, > but not both. That is, the ELT becomes a factor only in the case of a true > emergency, in which case I would first squawk emergency and communicate the > situation by VHF voice (flying the airplane first, of course). Then, > activate the ELT (one button press) if a forced landing appears inevitable, > but I'm probably done talking on the radio at that point. > > Is the concern simply the presence of another vertically oriented conductor > in relatively close proximity to the antenna in use, thus influencing its > performance? Even if both the ELT and the VHF radio are active at the same > time, is 3 ft of separation important? > > At any rate, it would be more convenient from an installation perspective to > put them closer together. Any advice? Give it a try . . . but with a Plan-B for moving one or both of the antennas to achieve demonstrably necessary separation. I suspect that not all ELT products are victim to the hypothesized vulnerability I cited above. There are no grave performance issues that would arise from antenna proximity issues so if you "get away Scott free" with your desired configuration, you're good to go. Bob . . . ________________________________ Message 9 _____________________________________ Time: 08:19:45 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: ELT antenna placement At 09:27 AM 7/16/2011, you wrote: > >Another risk is that many ELT transmitters are poorly shielded from >strong adjacent RF. Flying near a TV or FM transmitter antenna can >cause the oscillator of the ELT transmitter to radiate harmonics, >which then are picked up by your com radio, breaking squelch and >causing poor reception. My plane used to suffer from this syndrome >until I moved one of the VHF antennas to the belly. Interesting! I hadn't thought of that scenario. Unlike transceivers where the antenna is connected to a receiver input circuit 99.9% of the time, the ELT antenna is permanently connected to the output circuitry of a transmitter's power output stage. A strong analog TV station impressed on the ELT antenna could be conducted into the non-linear, transistor junctions where the TV signal could produce inter-modulation products that spread over a very wide spectrum. Now that we're all-digital in the off-air TV world, I suspect probability is reduced. I'm aware of no other "trash rich" high power signals that would produce this effect today. This is a phenomenon that was never explored by DO-160 although I've read some military qualification test protocols that do look for inter-modulation mixing and re-radiation of foreign energies coming down the antenna feedline. Bob . . . ________________________________ Message 10 ____________________________________ Time: 08:49:09 AM PST US From: BobsV35B@aol.com Subject: AeroElectric-List: ELT antenna placement Good Morning Paul and Jared, Way out of my area of expertise, but it is my understanding that having another vertical metal element close to the transmitting or receiving antenna makes the combination very directional. Rarely a problem when close to the station but could reduce the range capability at some angles from the aircraft. Happy Skies, Old Bob Do Not Archive In a message dated 7/16/2011 3:42:58 A.M. Central Daylight Time, email@jaredyates.com writes: In one prior case, we had an airplane that was transmitting ground control voice (121.9) over 121.5. We attributed it to resonance on the elt antenna, which was in a non standard location for that type, closer than normal to the vhf com. After moving the elt antenna back a couple of feet the bleed over stopped. This type of problem might be something to consider in your decision. On Jul 16, 2011, at 1:28, Paul Kuntz <_paul.r.kuntz@gmail.com_ (mailto:paul.r.kuntz@gmail.com) > wrote: I'm installing a 121.5/406 MHz ELT in my homebuilt project. The installation instructions tell me to put the ELT whip antenna at least 3 feet from my VHF radio antenna. Is this really necessary? There is the possibility of manually activating the ELT in the air in the event of an emergency, while continuing to communicate with the VHF radio, but I'm thinking that the more likely scenarios will be to operate one or the other, but not both. That is, the ELT becomes a factor only in the case of a true emergency, in which case I would first squawk emergency and communicate the situation by VHF voice (flying the airplane first, of course). Then, activate the ELT (one button press) if a forced landing appears inevitable, but I'm probably done talking on the radio at that point. Is the concern simply the presence of another vertically oriented conductor in relatively close proximity to the antenna in use, thus influencing its performance? Even if both the ELT and the VHF radio are active at the same time, is 3 ft of separation important? At any rate, it would be more convenient from an installation perspective to put them closer together. Any advice? Thanks, Paul Kuntz ________________________________ Message 11 ____________________________________ Time: 11:13:28 AM PST US Subject: Re: AeroElectric-List: Re: Viking Engine From: Ed Gilroy classy... On Fri, Jul 15, 2011 at 5:55 PM, b d wrote: > FO > > On Fri, Jul 15, 2011 at 2:18 PM, Richard Girard wrote: > >> Bruce, The discussion has been interesting to me, certainly more than your >> rather rude comment. >> >> Rick Girard >> >> On Fri, Jul 15, 2011 at 11:40 AM, b d wrote: >> >>> WOW, was this spam helpful to anyone? Just curious . . . . >>> >>> >>> >>> >>> >>> On Fri, Jul 15, 2011 at 4:37 AM, wrote: >>> >>>> >>>> 7/15/2011 >>>> >>>> Congratulations Fellow Amateur Builders, >>>> >>>> Several years ago when I first began to read amateur builder postings in >>>> various venues I was dismayed and concerned about the general lack of >>>> knowledge regarding the fundamental rules governing our community and >>>> the >>>> casual attitude towards such rules. Postings consisting of speculation, >>>> hearsay, gossip, and rumors would go on at length about any particular >>>> subject with not one poster citing the fundamental document governing >>>> the >>>> subject or even hinting that such a document may even exist. >>>> >>>> What a change we have seen. While there was significant thread creep on >>>> the >>>> aeroelectric list away from Viking Engine(s) per se in this thread >>>> several >>>> posters got directly >>>> into whatever side path may have been taken and provided clarification >>>> by >>>> stating outright, or provided links to, the facts contained in the >>>> controlling documents.** >>>> >>>> Demonstrating this knowlege, and a responsible attitude towards the >>>> rules, >>>> is very healthy for our amateur built community as aviation is already >>>> seen >>>> by the general public, with significant help from the lame stream media, >>>> as >>>> fraught with risky ventures and amateur builders ("nut case builds >>>> airplane >>>> in his grarage") as being probably totally irresponsible. >>>> >>>> Let's keep up the good work and help stamp out speculation, hearsay, >>>> gossip, >>>> and rumors as a means of communication (and confusion for the new guys) >>>> when >>>> the facts are usually readily available in this great day of the >>>> internet. >>>> >>>> 'OC' Baker Says: "The best investment we can make is the time and effort >>>> to >>>> gather and understand knowledge." >>>> >>>> **PS: I am not suggesting that all of the controlling documents (or the >>>> bureaucrats that enforce them) are all wise and should be followed >>>> slavishly. I am suggestion that if one decides to deviate from the rules >>>> that the deviation be done with knowledge and deliberation not out of >>>> ignorance. >>>> >>>> DO NOT ARCHIVE >>>> >>>> >>>> >>>> >>>> ====**==============================**= >>>> -List" target="_blank">http://www.matronics.com/** >>>> Navigator?AeroElectric-List >>>> ====**==============================**= >>>> http://forums.matronics.com >>>> ====**==============================**= >>>> le, List Admin. >>>> ="_blank">http://www.matronics.com/**contribution >>>> ====**==============================**= >>>> >>>> >>>> >>>> >>> * >>> >>> ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List >>> tp://forums.matronics.com >>> _blank">http://www.matronics.com/contribution >>> * >>> >>> >> >> >> -- >> Zulu Delta >> Mk IIIC >> Thanks, Homer GBYM >> >> It isn't necessary to have relatives in Kansas City in order to be >> unhappy. >> - Groucho Marx >> >> >> * >> >> ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List >> tp://forums.matronics.com >> _blank">http://www.matronics.com/contribution >> * >> >> > * > > * > > ________________________________ Message 12 ____________________________________ Time: 03:02:33 PM PST US From: Peter Pengilly Subject: Re: AeroElectric-List: It's nice when the center holds . . . But ... the F-16 is a 1980s design, and retro-fitting a gas turbine generator would be a lot of work to fix what is essentially a maintenance problem that everyone is already trained to deal with. If you were designing an all electric airplane today I'm guessing it would have some kind of turbine based generator to produce a few 10s of kW that would kick in really quickly. Peter For example ... http://www.lockheedmartin.com/news/press_releases/2005/UNIQUEINTEGRATEDSYSTEMSTARTSF35ENGI.html Do not archive On 16/07/2011 15:37, Robert L. Nuckolls, III wrote: > Given the advances in really tiny gas turbines, it > seems certainly possible and perhaps practical to > craft a light weight power generation device with > considerable output and endurance while using up > much less volume and weight budget needed for batteries > of the same capability. > > Some ideas take a very long time to evolve into > useful product . . . ________________________________ Message 13 ____________________________________ Time: 04:00:24 PM PST US From: Dave Saylor Subject: Re: AeroElectric-List: It's nice when the center holds . . . Reading about the starter-generator-APU brings up a question I've wondered about many times: why don't piston engines don't have starter-generators, or starter-alternators, or something like that? The two devices are so similar it seems like merging the two is obvious. Surely there must be some basic reason it wouldn't work. Bob? Dave Saylor AirCrafters 140 Aviation Way Watsonville, CA 95076 831-722-9141 Shop 831-750-0284 Cell On Sat, Jul 16, 2011 at 2:58 PM, Peter Pengilly wrote: > > > But ... the F-16 is a 1980s design, and retro-fitting a gas turbine > generator would be a lot of work to fix what is essentially a maintenance > problem that everyone is already trained to deal with. If you were designing > an all electric airplane today I'm guessing it would have some kind of > turbine based generator to produce a few 10s of kW that would kick in really > quickly. > > Peter > > For example ... > http://www.lockheedmartin.com/news/press_releases/2005/UNIQUEINTEGRATEDSYSTEMSTARTSF35ENGI.html > > Do not archive > > On 16/07/2011 15:37, Robert L. Nuckolls, III wrote: >> >> Given the advances in really tiny gas turbines, it >> seems certainly possible and perhaps practical to >> craft a light weight power generation device with >> considerable output and endurance while using up >> much less volume and weight budget needed for batteries >> of the same capability. >> >> Some ideas take a very long time to evolve into >> useful product . . . > > ________________________________ Message 14 ____________________________________ Time: 04:13:17 PM PST US From: "Neal George" Subject: RE: AeroElectric-List: It's nice when the center holds . . . Gentlemen - The Cliff Notes from a retired F-16-driver buddy: There are many batteries on the F-16 but they are relatively small. Each of the axis of the flight control computer has a FLCS battery (3) and then there are others as well as the A/C battery. But, the EPU, not APU, is an emergency power unit powered by hydrazine that flows across an iridium catalyst to product energy. The hydrazine is pressurized with nitrogen I believe and flows from the tank across the catalyst. It then runs a small turbine (at a very high rpm) which in turn powers an aux hydraulic pump with also powers a small aux generator. It is good for a finite period of time (of which I do not recall) and basically dumps water vapor overboard. neal =========== Bob, I don't know F-16 systems, but have experience of other single seat military aircraft. I'm guessing the Hydrazine unit is a light weight method of mitigating the hazard of providing power once the (single) motor has stopped, without fitting a huge battery. Most combat aircraft are started with a ground power unit, so the battery doesn't have to be very big. I'm guessing the electrical demands of an F-16 are quite large (fly-by-wire), even with load shedding, so a huge battery would be required to get the airplane to the ground from max altitude - or a reasonably powerful (heavy) gas turbine APU. So a one shot hydrazine based system is a reasonable (light weight) solution, although it has a maintenance overhead. Bear in mind the F-16 was designed as a lightweight fighter, so weight saving was probably quite high on the priority list. That's about what I would have guessed. Some years ago, there was some work described in the development of tiny, combustion driven turbines for hi-energy stand-by sources. One author even hypothesized a lap-top computer running on butane. Haven't heard/read anything along those lines since. The GAR series IR guided missiles I used to work on at Hughes-Tucson had a little bottle of nitrogen held in liquid state at room temperatures . . . man, that was a lot of pressure! A frangible diaphragm held the liquid in check until launch. Then for the 90-second or so service life of the missile, the liquid expanded to run a small PM alternator that produced 150 watts to power electronics. It was then routed to the back of the IR optics to keep the lens cool at Lots-a-Mach. After that, it pressurized an open loop hydraulic system that operated flight controls at the trailing edges of the guidance fins before being exhausted overboard. That was in 1960. Given the advances in really tiny gas turbines, it seems certainly possible and perhaps practical to craft a light weight power generation device with considerable output and endurance while using up much less volume and weight budget needed for batteries of the same capability. Some ideas take a very long time to evolve into useful product . . . Bob . . . ________________________________ Message 15 ____________________________________ Time: 05:06:39 PM PST US From: Kelly McMullen Subject: Re: AeroElectric-List: ELT antenna placement It was particularly obnoxious in Phoenix, where the VFR transition over Sky Harbor has you aimed right at an antenna farm that has 80 percent of all broadcast stations for the area, distance less than 7 nm. Probably a few million watts being radiated between the FM and TV stations transmitters there. As soon as I disconnected the ELT coax from the ELT, I could fly right up within a mile of those towers with no problem, but with it connected, as soon as I got within 10 nm constant squelch break and weak reception both on KX155 and on KX170(McCoy conversion). Had it happen elsewhere, but not where it caused problems when I had to be in communication with approach inside Class B airspace. Fixed as soon as I removed one of Comant 121 antennas from top of fuselage and replaced with Comant 122 on belly. I've heard of many other ELT installs having same problem. As you say, I don't think there were a lot of requirements for RF interference back in 1973 when the TSO was originally written. On 7/16/2011 8:16 AM, Robert L. Nuckolls, III wrote: > > Interesting! I hadn't thought of that scenario. Unlike > transceivers where the antenna is connected to a receiver > input circuit 99.9% of the time, the ELT antenna is > permanently connected to the output circuitry of a > transmitter's power output stage. > > A strong analog TV station impressed on the ELT > antenna could be conducted into the non-linear, > transistor junctions where the TV signal could > produce inter-modulation products that spread over > a very wide spectrum. Now that we're all-digital > in the off-air TV world, I suspect probability > is reduced. I'm aware of no other "trash rich" > high power signals that would produce this > effect today. > > This is a phenomenon that was never explored > by DO-160 although I've read some military > qualification test protocols that do look for > inter-modulation mixing and re-radiation of > foreign energies coming down the antenna feedline. > > > Bob . . . > > ________________________________ Message 16 ____________________________________ Time: 06:51:16 PM PST US Subject: Re: AeroElectric-List: ELT antenna placement From: Paul Kuntz Thanks for all the feedback. Seems like the prudent approach will be to accept the ELT installation instructions and mount the ELT at the specified 3+ feet of separation from the VHF antenna. I'd rather do that now than face the potential for troubleshooting and installation rework later. Paul Kuntz On Sat, Jul 16, 2011 at 7:51 AM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > > > At 07:10 AM 7/16/2011, you wrote: > dave.saylor.aircrafters@**gmail.com > > > I agree, I've seen comm radios set of a nearby ELT on several > occasions. It's not uncommon at all. > > I'd keep those antennas away from each other. > > It would appear to be the only option. It > may be very $difficult$ to fix what appears > to be a design bug internal to the ELT. > > The earliest ELT's used a spring-loaded > mass to close an activation switch in response > to g-forces of a crash. No doubt modern ELTs > use the solid-state acceleration sensors > for this task . . . which produce VERY tiny > signals requiring a lot of circuit gain. > > This type of circuitry offers a high risk > of vulnerability to RF interference. This > may be an area where qualification of the > device to standard DO-160 (good for part > 23) stresses was insufficient to stand off > the extra-ordinary vulnerabilities of these > kinds of circuits. A lot of hardware we > did for the military and for Part-25 and up > applications was exposed to really nasty > RF radiation . . . 200 volts/meter or more > . . . during qualification. No doubt this > extra step in qualification would have exposed > vulnerabilities that are now plaguing customers. > > > Paul wrote: > > > I'm installing a 121.5/406 MHz ELT in my homebuilt project. =C2 The > > > installation instructions tell me to put the ELT whip antenna at least 3 > > feet from my VHF radio antenna. =C2 Is this really necessary? =C2 There is > the > > > possibility of manually activating the ELT in the air in the event of a n > > emergency, while continuing to communicate with the VHF radio, but I'm > > thinking that the more likely scenarios will be to operate one or the > other, > > but not both. =C2 That is, the ELT becomes a factor only in the case of a > true > > > emergency, in which case I would first squawk emergency and communicate > the > > situation by VHF voice (flying the airplane first, of course). =C2 Then , > > > activate the ELT (one button press) if a forced landing appears > inevitable, > > but I'm probably done talking on the radio at that point. > > > > Is the concern simply the presence of another vertically oriented > conductor > > in relatively close proximity to the antenna in use, thus influencing i ts > > performance? =C2 Even if both the ELT and the VHF radio are active at t he > same > > > time, is 3 ft of separation important? > > > > At any rate, it would be more convenient from an installation perspecti ve > to > > put them closer together. =C2 Any advice? > > Give it a try . . . but with a Plan-B for moving > one or both of the antennas to achieve demonstrably > necessary separation. I suspect that not all ELT > products are victim to the hypothesized vulnerability > I cited above. There are no grave performance issues > that would arise from antenna proximity issues so if > you "get away Scott free" with your desired configuration, > you're good to go. > > > Bob . . . > > =====**=================== ===========**= /www.matronics.com/Navigator?AeroElectric-List> =====**=================== ===========**= =====**=================== ===========**= com/contribution> =====**=================== ===========**= > > ________________________________ Message 17 ____________________________________ Time: 07:44:36 PM PST US From: "Paul Zimmer" Subject: AeroElectric-List: Electrical System Drawing Attached is a draft electrical schematic based primarily on Bob Nuckolls' Z-13 electrical system drawing. Note that I plan on using an internally regulated Plane Power 30A backup alternator, which is supposed to be out by Oshkosh. If not, I'll use the B&C SD-20. The reason for the second 7.2 AH battery is to insure field current to the backup alternator in the event of main battery failure. I have thought of using a second full sized battery as the AUX, which I would connect in parallel with the main battery for more cranking power. Questions I have are: Is an Avionics bus & switch unnecessary or is it still a good idea? I like the idea, and I know the GTX 327 is supposed to be powered off during engine start. Also the GTN 6xx install doc says it should be on an Avionics bus. Others have suggested (and even said that Bob Nuckolls doesn't think much of the idea in his book - although I couldn't find anywhere he discussed it) that the avionics bus is unnecessary with modern avionics, adds complexity and additional potential points of failure. Bob doesn't show it on the drawings I've studied, so I'm wondering. What are the failure modes of the EBUS Diode? Will it ever fail open? If it fails and allows reverse current, what is the best way to detect the failure? My schematic has a battery bus drawn, but I really don't see a need for it. Other than a clock and interior lights, is there something that I have placed on another bus that really should be on a battery bus? What about the location of the backup alternator? I show it connected to the essential bus instead of the un-switched side of the battery contactor, in the event of a dead short in the battery. I'm not sure if that's a failure mode I need to even consider. Another thing I've though of is although I haven't done a load analysis yet, but I'm pretty sure with a 30A backup alternator, I could combine the Avionics and E-Bus busses (the only things that would be added to the E-BUS would be Com2, Transponder and audio panel. Any comments and criticism of the design would be greatly appreciated. The aircraft I am building is an RV-7A. The mission is day/night IFR. Thanks Paul ________________________________ Message 18 ____________________________________ Time: 07:50:29 PM PST US From: "Paul Zimmer" Subject: AeroElectric-List: Electrical System Drawing Attached is a draft electrical schematic based primarily on Bob Nuckolls' Z-13 electrical system drawing. Note that I plan on using an internally regulated Plane Power 30A backup alternator, which is supposed to be out by Oshkosh. If not, I'll use the B&C SD-20. The reason for the second 7.2 AH battery is to insure field current to the backup alternator in the event of main battery failure. I have thought of using a second full sized battery as the AUX, which I would connect in parallel with the main battery for more cranking power. Questions I have are: Is an Avionics bus & switch unnecessary or is it still a good idea? I like the idea, and I know the GTX 327 is supposed to be powered off during engine start. Also the GTN 6xx install doc says it should be on an Avionics bus. Others have suggested (and even said that Bob Nuckolls doesn't think much of the idea in his book - although I couldn't find anywhere he discussed it) that the avionics bus is unnecessary with modern avionics, adds complexity and additional potential points of failure. Bob doesn't show it on the drawings I've studied, so I'm wondering. What are the failure modes of the EBUS Diode? Will it ever fail open? If it fails and allows reverse current, what is the best way to detect the failure? My schematic has a battery bus drawn, but I really don't see a need for it. Other than a clock and interior lights, is there something that I have placed on another bus that really should be on a battery bus? What about the location of the backup alternator? I show it connected to the essential bus instead of the un-switched side of the battery contactor, in the event of a dead short in the battery. I'm not sure if that's a failure mode I need to even consider. Another thing I've though of is although I haven't done a load analysis yet, but I'm pretty sure with a 30A backup alternator, I could combine the Avionics and E-Bus busses (the only things that would be added to the E-BUS would be Com2, Transponder and audio panel. Any comments and criticism of the design would be greatly appreciated. The aircraft I am building is an RV-7A. The mission is day/night IFR. Thanks Paul ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.