AeroElectric-List Digest Archive

Fri 10/14/11


Total Messages Posted: 17



Today's Message Index:
----------------------
 
     1. 04:43 AM - Re: Optical Switch? (jhausch)
     2. 05:23 AM - hello aeroelectric-list@matronics.com (Rodney Dunham)
     3. 08:35 AM - Toyota (denso) alternator (Janet Amtmann)
     4. 08:35 AM - Re: Re: Halogen bulbs with wig wag circuitry....failure mode (Robert L. Nuckolls, III)
     5. 09:11 AM - Lithium batteries (Robert L. Nuckolls, III)
     6. 09:16 AM - Re: hello aeroelectric-list@matronics.com (HIGH RISK) (Robert L. Nuckolls, III)
     7. 09:31 AM - Re: Toyota (denso) alternator (Robert L. Nuckolls, III)
     8. 09:39 AM - Re: Toyota (denso) alternator (OOPS) (Robert L. Nuckolls, III)
     9. 09:43 AM - Re: Optical Switch? (jonlaury)
    10. 10:38 AM - Re: Re: Halogen bulbs with wig wag circuitry....failure mode (David Lloyd)
    11. 12:51 PM - Needed Grimes Position Light Parts (Jerald Folkerts)
    12. 12:55 PM - Re: Re: Halogen bulbs with wig wag circuitry....failure mode (Robert L. Nuckolls, III)
    13. 06:22 PM - Re: Re: Optical Switch? (Bob McCallum)
    14. 07:24 PM - Re: Re: Lithium Batteries? (Noel Loveys)
    15. 07:50 PM - Re: Electric aircraft issues (Robert L. Nuckolls, III)
    16. 07:57 PM - Re: Re: Electric aircraft issues (Robert L. Nuckolls, III)
    17. 08:09 PM - Re: Re: Lithium Batteries? (Robert L. Nuckolls, III)
 
 
 


Message 1


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    Time: 04:43:15 AM PST US
    Subject: Re: Optical Switch?
    From: "jhausch" <jimhausch@gmail.com>
    jonlaury wrote: > I need a switch that activates when something moves in front of a sensor. This is not an aviation application. But I'm sure that someone on the list can save me having to decipher all the offerings on Digi-key. > > I'm envisioning something similar to a garage door opener saftey beam/switch, but way smaller, to operate on 12 vdc, for detection of material in a machine process. > > Thanks for any help, > John John, Bob is right on the mark. It sounds like he and I both make our living in the factory automation world. If you just need one photo eye, I may have an old demo unit I can send you or sell cheaply* Since you said this was for a machine I am a little surprised you need 12v since most machines use 24v, but most industrial dc sensors do run on 10-30vdc. I am in a meeting from 8-12 central time today, but could discuss your application with you this afternoon. Email either of us and we should be able to get you sorted out straightaway. I forget which email address I have tied to this list, so use jimhausch (at symbol) gmail (dot) com *cheap is a relative term...simple industrial sensors can sell from 10 to 100 bucks. Folks with a knowledge of circuitry (like folks who might hang out here :) ) know the base component costs for a simple photo eye can be had for pennies. I will never forget a sales call I made where the customer wanted a simple emitter-receiver pair to run on AC power. I told for single piece quantities, including the cables he needed and offering the output rating he needed, might cost $100. He said "what! I can buy a garage door opener that includes two photo eyes for $100!"..... such is life :) Jim Read this topic online here: http://forums.matronics.com/viewtopic.php?p=354980#354980


    Message 2


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    Time: 05:23:12 AM PST US
    From: Rodney Dunham <rdunhamtn@hotmail.com>
    Subject: hello aeroelectric-list@matronics.com
    hey aeroelectric-list@matronics.com wow this is crazy http://www.todayslocal10.com


    Message 3


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    Time: 08:35:11 AM PST US
    Subject: Toyota (denso) alternator
    From: Janet Amtmann <jgamtmann2@gmail.com>
    I am using an internally regulated Toyota (Denso) alternator on my RV6. It has the normal B+ charging lead and a plug with 3 spade connectors. One is for the light, one for sense and one labeled IGN that supplies 12V to energize the alternator before it starts running. Can anyone tell me what happens to the output of this alternator if the IGN wire is disconnected during flight (i.e. while the alternator is running)? I have my alternator switch in this IGN line to take the alternator Off Line, but something tell s me this is not a good idea and that the alternator output may run away. Regards, J=FCrgen Amtmann


    Message 4


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    Time: 08:35:11 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Halogen bulbs with wig wag circuitry....failure
    mode At 12:17 PM 10/12/2011, you wrote: > >Since this bulb failure issue was my original message and problem, I >can add only another piece of mechanical evidence that may or may >not have anything to do with the H7604 filament failures.... >1. Under magnification, both filaments separated not in the coil >section, but, on the short straight ends just before their connection post. >2. I do not know if the filaments (bulbs) were originally installed >in the vertical or horizontal orientation. Rumor has it, that >installing with the filaments vertically removes some of the >mechanical stress from wing vibration and landing stresses. >3. I have installed the new H7604's with the filaments in the >vertical orientation and will report in the future if this seems to >extend the bulb life. Hmmmm . . . I'm suspicious of any 'benefit' for orientation of filaments to increase resistance to vibration stresses. Most materials exhibit a thing called a stress-to-events-ratio (S/N ratio) where a number of events at a particular stress level are required to structurally fail the material. Further, the S/N curve is generally not linear. In other words, raising the stress level by a factor of 3 does not necessarily result in failure at 1/3rd the number of cycles. It might drop to 1/4th the number of cycles. Stress transients on landing are short duration but very few in number compared hours of in-flight stimulus. Tungsten has a unique metallurgical property where the metal transforms from a brittle to a ductile state at a rather low temperature. I think it was on the order 500F. In any case, it was below the dull-red-glow temperature. In the chapter on lighting in the 'Connection, I described two techniques for keeping a filament warm when the light was OFF. Maintaining the brittle filament at or above it's brittle-to-ductile transition temperature has a marked effect on the S/N ratio. It would be a very interesting experiment to try some form of keep-warm system on an airplane that exhibits a high failure rate for tungsten filament lamps. Bob . . .


    Message 5


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    Time: 09:11:36 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Lithium batteries
    In the days since this topic was last discussed here on the list, I've done a little research into the number and nature of 'battery induced fires' aboard aircraft. This was one of several interesting documents I ran across during the search . . . http://safetravel.dot.gov/Action_Plan.pdf I have yet to discover a description of a battery fire involving a SYSTEM battery on the 'net. If anyone runs across such a narrative, I'd be pleased to have the link. The ramp fire on the Cessna is the first incident I'm aware of and that information was 'through the grapevine'. Industry focus has been on the vast majority of battery fires where the devices were either packaged for shipment as cargo/baggage or in relatively light duty service as a component of a personal electronic device in passenger spaces. The document I cited states that only 27% of incidents studied involved lithium batteries. The remainder were other technologies, lead-acid being the most probable. The consensus for root cause of battery fires trends toward short circuits . . . which is not a technology issue but a process issue. This short study suggests that our deliberations will not benefit from a study of battery fire incidents in the wild. The study confirms what we already knew. Batteries offer very high concentrations of energy in small volumes. Unintentional and uncontrolled release of that energy poses risks. Lithium elevates those risks by ADDING combustible materials to the potential release of energy. So as the experiments and discussion of our SYSTEM batteries goes forward, let's keep those differences in mind. Further, it is probable that a citation of most battery fire incidents in the wild will add little or no useful information to the conversation. Bob . . .


    Message 6


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    Time: 09:16:59 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: hello aeroelectric-list@matronics.com (HIGH RISK)
    At 12:19 AM 10/14/2011, you wrote: > >hey aeroelectric-list@matronics.com wow this is crazy >http://www.todayslocal10.com Rodney, Has your email address been hijacked? List-Members. Hitting on this link is HIGH RISK not unlike the incident that visited the list a few weeks ago. Bob . . .


    Message 7


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    Time: 09:31:53 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Toyota (denso) alternator
    At 10:30 AM 10/14/2011, you wrote: I am using an internally regulated Toyota (Denso) alternator on my RV6. It has the normal B+ charging lead and a plug with 3 spade connectors. One is for the light, one for sense and one labeled IGN that supplies 12V to energize the alternator before it starts running. Can anyone tell me what happens to the output of this alternator if the IGN wire is disconnected during flight (i.e. while the alternator is running)? I have my alternator switch in this IGN line to take the alternator Off Line, but something tells me this is not a good idea and that the alternator output may run away. Regards, Jrgen Amtmann The risks of uncontrollable runaway for internally regulated alternators is very low but not zero. Commercial offerings of automotive conversions for aircraft either modify the alternator for EXTERNAL regulation and OV protection (a la B&C) or get modified to accept external OV protection (a la Plane-Power). No doubt there are thousands of internally regulated alternators flying without ov protection that have never experienced a runaway failure . . . but there have been a few . . . with predictable results. The choice is yours. Bob . . .


    Message 8


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    Time: 09:39:24 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Toyota (denso) alternator (OOPS)
    At 10:30 AM 10/14/2011, you wrote: I am using an internally regulated Toyota (Denso) alternator on my RV6. It has the normal B+ charging lead and a plug with 3 spade connectors. One is for the light, one for sense and one labeled IGN that supplies 12V to energize the alternator before it starts running. Can anyone tell me what happens to the output of this alternator if the IGN wire is disconnected during flight (i.e. while the alternator is running)? OOPS! I hit the 'send' button too soon. Controlling power to the IGN lead will place the alternator off/on-line while the engine is running. It's not an unsafe or risky thing to do. However, there are failures internal to the regulator that cannot be controlled by the switched IGN lead. Suggest you review the articles on ov protection here: http://tinyurl.com/3hj8gm2 I have my alternator switch in this IGN line to take the alternator Off Line, but something tells me this is not a good idea and that the alternator output may run away. Regards, J=FCrgen Amtmann The risks of uncontrollable runaway for internally regulated alternators is very low but not zero. Commercial offerings of automotive conversions for aircraft either modify the alternator for EXTERNAL regulation and OV protection (a la B&C) or get modified to accept external OV protection (a la Plane-Power). No doubt there are thousands of internally regulated alternators flying without ov protection that have never experienced a runaway failure . . . but there have been a few . . . with predictable results. The choice is yours. Bob . . .


    Message 9


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    Time: 09:43:12 AM PST US
    Subject: Re: Optical Switch?
    From: "jonlaury" <jonlaury@impulse.net>
    To All, Thanks for your input/suggestions. Here's more information to help narrow the choices. The gap to be sensed is Read this topic online here: http://forums.matronics.com/viewtopic.php?p=355010#355010


    Message 10


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    Time: 10:38:37 AM PST US
    From: "David Lloyd" <skywagon@charter.net>
    Subject: Re: Halogen bulbs with wig wag circuitry....failure
    mode Bob, You are always surprising me with your knowledge background. My grey matter stores a lot and I have a degree in electronics, however, I learn constantly from your inputs to all these problems and questions. Funny, I did not know that the halogen environment still included tungsten filaments. I was assuming, some other mixture of metal was the basis for these brighter lamps. You bring up an interesting option...to keep the lamp filaments in their flexible or ductile stage while in any none use state. I wonder what level of current would be needed for that in a 12 - 14 v. system. And, an option would have to be planned in the case of an alternator failure to cut the background lamp current. Thanks, David ______________________________________________________________ ----- Original Message ----- From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com> Subject: Re: AeroElectric-List: Re: Halogen bulbs with wig wag circuitry....failure mode > > At 12:17 PM 10/12/2011, you wrote: >> >>Since this bulb failure issue was my original message and problem, I can >>add only another piece of mechanical evidence that may or may not have >>anything to do with the H7604 filament failures.... >>1. Under magnification, both filaments separated not in the coil section, >>but, on the short straight ends just before their connection post. >>2. I do not know if the filaments (bulbs) were originally installed in >>the vertical or horizontal orientation. Rumor has it, that installing >>with the filaments vertically removes some of the mechanical stress from >>wing vibration and landing stresses. >>3. I have installed the new H7604's with the filaments in the vertical >>orientation and will report in the future if this seems to extend the bulb >>life. > > Hmmmm . . . I'm suspicious of any 'benefit' for > orientation of filaments to increase resistance > to vibration stresses. Most materials exhibit a > thing called a stress-to-events-ratio (S/N ratio) > where a number of events at a particular stress > level are required to structurally fail the > material. Further, the S/N curve is generally > not linear. In other words, raising the stress > level by a factor of 3 does not necessarily > result in failure at 1/3rd the number of cycles. > It might drop to 1/4th the number of cycles. > Stress transients on landing are short duration > but very few in number compared hours of in-flight > stimulus. > > Tungsten has a unique metallurgical property where > the metal transforms from a brittle to a ductile > state at a rather low temperature. I think it was > on the order 500F. In any case, it was below the > dull-red-glow temperature. In the chapter on > lighting in the 'Connection, I described two > techniques for keeping a filament warm when the > light was OFF. Maintaining the brittle filament > at or above it's brittle-to-ductile transition > temperature has a marked effect on the S/N ratio. > > It would be a very interesting experiment to > try some form of keep-warm system on an airplane > that exhibits a high failure rate for tungsten > filament lamps. > > > Bob . . . > > >


    Message 11


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    Time: 12:51:18 PM PST US
    From: "Jerald Folkerts" <jfolkerts1@gmail.com>
    Subject: Needed Grimes Position Light Parts
    At Sun-N-Fun this year, I purchased a used set of position/tail lights in the tent. My plan was to use the PSA Enterprises LED replacement lenses for a simple LED lighting system on my Murphy Super Rebel. When I got home, one of the lights had no guts, i.e. the spring, phenolic washer, plastic washer, wood spacer, and metal center pin. Before I hit the salvage yards, does anyone have a single light or light parts laying around? I just need the guts - WTB. I suppose I could machine the parts as well - probably not to difficult other than time. Lesson learned, beware of parts in sealed bags. Thanks, Jerry Folkerts SR2500 #093 www.mykitlog.com/jfolkerts


    Message 12


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    Time: 12:55:50 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Halogen bulbs with wig wag circuitry....failure
    mode > >Funny, I did not know that the halogen environment still included >tungsten filaments. I was assuming, some other mixture of metal was >the basis for these brighter lamps. It's my assumption that they're still tungsten. A quick look at Wikipeda http://en.wikipedia.org/wiki/Halogen_lamps didn't suggest any 'new' materials. You bring up an interesting option...to keep the lamp filaments in their flexible or ductile stage while in any none use state. I wonder what level of current would be needed for that in a 12 - 14 v. system. The POWER needed is quite low but the current is substantial due to the large positive temperature coefficient of lamp resistance. I just took a couple 14v halogen lamps to the bench and was able to get the first signs of visible light (tiny red glow) at about 1.5 volts. However, the current draw was a substantial portion of rated current at full voltage. One example: A lamp I tested gave me first visible light at 1.5V and 1.7A for a total of about 2.6W. This lamp was rated at 55W at 14V or 3.9A. This says that the resistor-diode technique described in the 'Connection would be terribly inefficient. But if you've got a fat alternator and some place to let the heat dump out . . . the technique may be practical . . . and low cost. The obvious solution is to use a 2 t0 2.5v DC-DC converter. There are a number of commercial off the shelf products. Many such devices can be purchased through the industrial surplus houses for a reasonable price. Alternatively, you can do your own DC-DC buck converter. There are a number of design tools on the 'net that will assist in component selection. The nice thing about it is that output ripple voltage can be pretty high. Light bulbs don't care. You WILL want to consider EMC filtering as these devices operate in the 0.1 to 1.0 MHz range and would be pretty noisy. The fast-turn solution might be to use an LED driver like the Buck Puck 2100 mA device http://www.ledsupply.com/0a009-d-v-2100.php throttled down through the dimming input to get you a barely visible light output in a dark hangar. EMC questions apply here too. The neat thing about DC to DC conversion is efficiency. Something like the Buck-Puck should be 85% efficient or better. A 2.5 watt keep warm system for a 55w lamp would only need 3W or so from the bus. Another plus of the Buck Pucks is that they're rated for up to 32 volts operating voltage. PLENTY of headroom for observing DO-160 surge requirements in a 14v system. And, an option would have to be planned in the case of an alternator failure to cut the background lamp current. Thanks, You bet. Of course, things light landing lights might drive from the main bus which would be down during battery only ops anyhow. If you've got battery left over on short final, then bring the main bus back up and use the landing light. The keepwarm circuit is a great mitigation of inrush current too. Bob . . .


    Message 13


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    Time: 06:22:24 PM PST US
    From: Bob McCallum <robert.mccallum2@sympatico.ca>
    Subject: Re: Optical Switch?
    John; Based on the new information you've supplied an Omron E3Z-T61 0.5M or E3Z-T61A 0.5M should do the trick or you could go to a fiber optic series such as the E3X-A11 or E3X-A41 which use a 2mm plastic fiber optic cable to transmit the light beam allowing the actual sensor to be remotely mounted. The T61 is an infrared sensor; the T61A is visible red light. These sensors are NPN switching, if you need or desire PNP switching substitute an 8 for the 6 in the part # The E3X series are red visible light the A11 model is NPN the A41 model is PNP All of these sensors are through beam as you've requested. For the E3X series you can use unterminated fiber as a substitute for the rather expensive accessory fibers sold by Omron. I can send you several feet in the mail free should you decide to go that route. Just PM me your address if you wish some fiber. Bob McC > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list- > server@matronics.com] On Behalf Of jonlaury > Sent: Friday, October 14, 2011 12:40 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: Re: Optical Switch? > > > To All, > > Thanks for your input/suggestions. > Here's more information to help narrow the choices. > > The gap to be sensed is > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=355010#355010 > > > > > > > > _- > ==================================================== > ====== > _- > ==================================================== > ====== > _- > ==================================================== > ====== > _- > ==================================================== > ====== > >


    Message 14


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    Time: 07:24:43 PM PST US
    From: "Noel Loveys" <noelloveys@yahoo.ca>
    Subject: Re: Lithium Batteries?
    I've heard of much worse than this with a NiCad aircraft battery which almost resulted in a Sikorsky S-92 being unceremoniously dumped off an oil platform. Batteries are not always our friends. Noel -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Eric M. Jones Sent: October 11, 2011 9:45 PM Subject: AeroElectric-List: Re: Lithium Batteries? <emjones@charter.net> A few years ago I related to Bob N. my experience with a a couple 12V carbon-zinc Eveready lantern battery that I used to power a Telex intercom (which usually plugged into the rarely-connected cigar lighter). The first battery was found dead under mysterious circumstances (I was probably lucky). The replacement battery, upon shutting down the aircraft was too hot to touch and I grabbed it by the wires and tossed it out onto the asphalt. It melted a dent in the ramp. It was smoking. I surmised that the batteries had some internal crushing damage from rapid descent, but perhaps they were damaged from voltage fed back from the intercom. But I can't see how. The intercom was undamaged. This whole thing remains a mystery, but I offer it as a clue regarding batteries. Batteries might need to have mechanics that withstand deformation by rapid pressure changes. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones@charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=354739#354739


    Message 15


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    Time: 07:50:01 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Electric aircraft issues
    Posted: Mon Oct 10, 2011 4:02 am Bob: I recall working a MU2 accident down in TX that involved a ni-cad battery fire . . . Glen: was that the one involving a runaway battery that severed the pitch control system? No . . . at least I don't think so. This airplane used two sets of 24 volt ni-cads that were hooked in series to get 48 volts to start the engines; then reconnected in parallel for normal ops. My mentor, Ken Razak asked me to look at the series-parallel switching system as a potential root cause of the battery fire. The pilot got the airplane down on the ground from about 10K onto the grass adjacent to a runway. All souls got out and the fire crews were able to quickly put out the fire. Since the system was behaving normally for a departure and climb to 10K there was little reason to suspect that the series-parallel switching system was 'stuck' in an abnormal condition. But given the paralleled generators capable of putting many amps into those nice little light weight batteries, it was far more likely that the battery array suffered thermal runaway and went into self destruction. This was the era of before-battery-overheat-monitors. Some years later, a technician I hired to work with me in the video business mentioned a burned airplane he helped restore in Tx. Turns out it was the same MU-2, Bob . . .


    Message 16


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    Time: 07:57:51 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Electric aircraft issues
    Sun Oct 09, 2011 12:36 pm Hi Bob You mentioned: "The Shorai folks caution against an energetic recharge of a deeply depleted battery." This is not only true of a Lithium battery, but charging a discharged lead acid battery with a high powered alternator that's trying to maintain a constant voltage (just got aeroplane or car running from a jump start) is not very easy on the battery. How could one limit the charging amps going into the battery yet still allow the alternator to carry any loads? Ron P. It's not terribly difficult. We've had generator regulators that could not only limit the generator's output current . . . but the can current-balance to paralleled generators. It would not be difficult to design a regulator that would limit re-charge current to the battery. This would call for a scheduled reduction of bus voltage while the really beat battery catches it's breath. The voltage would not be so depressed that it hampered normal system operations . . . but such a regulator would have prevented ni-cad fires and eliminated the need to add the battery overheat monitor to ni-cad fitted airplanes. Bob . . .


    Message 17


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    Time: 08:09:29 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Lithium Batteries?
    At 09:20 PM 10/14/2011, you wrote: > >I've heard of much worse than this with a NiCad aircraft battery which >almost resulted in a Sikorsky S-92 being unceremoniously dumped off an oil >platform. Batteries are not always our friends. One could say the same thing about barrels of gasoline, 400 h.p. engines in street machines, or BD-5J airplanes. When operated within their respective limits compatible with the environment, they can seem quite benign and spectacularly useful. But in the wrong hands short of skill or knowledge, they can prove quite hazardous. I was out on a field trip with K. Razak many moons ago and had to slap out an escalating source of smoke and bad smells from a pants pocket. I'd tossed a handful of AA alkaline cells into the pocket with a bunch of coins and a key-ring. If those had been synthetic as opposed to good ol' denim Dickies, I might still bear the "mark of Duracell" on my thigh! I did it in good company. Had lots of lawyers standing around hoping we were going to do some good things for them. I told them that hat-dance entertainment was no extra charge. Now, if that had been a lithium cell . . . Bob . . .




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