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Light Speed Ignition with OV

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user9253

Joined: 28 Mar 2008
Posts: 1923
Location: Riley TWP Michigan

Posted: Sat Feb 07, 2009 6:56 pm Post subject: Light Speed Ignition with OV

There has been discussion recently about Light Speed Ignition with built in  OV protection based on a phone conversation with Light Speed.  And then  someone posted an excerpt from the installation manual which reads in part:  

 "Input voltages above 35 volts or reversed polarity will cause system  damage.  For this reason it is mandatory that all aircraft using Plasma CD  Ignitions are equipped with over-voltage protection in their alternator charging  system(s)."

 I interpret this to mean that there is no crowbar over-voltage protection  built into the Light Speed Ignition.  Otherwise, how could it be  damaged if high voltage is shorted by internal OV protection?  And why  would it be mandatory that the aircraft electrical system be equipped with OV  protection if it is already built into the ignition?  I suggest that there  was a misunderstanding in the conversation and that Light Speed Ignition systems  do NOT have built-in crowbar over-voltage protection.  The company should  issue a written statement to clarify this issue.  Otherwise prospective  customers might not want to buy their products if there is a perceived danger  that a charging system failure could stop the engine.

 Joe

   [quote][b]

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_________________
Joe Gores

mrspudandcompany(at)veriz
Guest

Posted: Sun Feb 08, 2009 5:46 am Post subject: Light Speed Ignition with OV

There has been discussion recently about Light Speed Ignition with built in OV protection based on a phone conversation with Light Speed.  And then someone posted an excerpt from the installation manual which reads in part:   

    

"Input voltages above 35 volts or reversed polarity will cause system damage.  For this reason it is mandatory that all aircraft using Plasma CD Ignitions are equipped with over-voltage protection in their alternator charging system(s)."  

    

I interpret this to mean that there is no crowbar over-voltage protection built into the Light Speed Ignition.  Otherwise, how could it be damaged if high voltage is shorted by internal OV protection?  And why would it be mandatory that the aircraft electrical system be equipped with OV protection if it is already built into the ignition?  I suggest that there was a misunderstanding in the conversation and that Light Speed Ignition systems do NOT have built-in crowbar over-voltage protection.  The company should issue a written statement to clarify this issue.  Otherwise prospective customers might not want to buy their products if there is a perceived danger that a charging system failure could stop the engine.  

    

Joe  

  [quote]  This is not a perceived danger, as you stated, but a real actual failure reported by more than 1 lister.  I agree that the company should issue a statement to clarify their design goals.  In the mean time, it appears that pilots should be aware of this potential problem and the power to the Light Speed Ignition systems should be fed through an easily accessible in flight circuit breaker. Roger [b]

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nuckolls.bob(at)aeroelect
Guest

Posted: Sun Feb 08, 2009 7:08 am Post subject: Light Speed Ignition with OV

At 07:36 AM 2/8/2009, you wrote:

  	  Quote: 	
		    

 There has been discussion recently about Light Speed Ignition with built in OV protection based on a phone conversation with Light Speed.  And then someone posted an excerpt from the installation manual which reads in part: 

 "Input voltages above 35 volts or reversed polarity will cause system damage.  For this reason it is mandatory that all aircraft using Plasma CD Ignitions are equipped with over-voltage protection in their alternator charging system(s)."

 I interpret this to mean that there is no crowbar over-voltage protection built into the Light Speed Ignition.  Otherwise, how could it be damaged if high voltage is shorted by internal OV protection?  And why would it be mandatory that the aircraft electrical system be equipped with OV protection if it is already built into the ignition?  I suggest that there was a misunderstanding in the conversation and that Light Speed Ignition systems do NOT have built-in crowbar over-voltage protection.  The company should issue a written statement to clarify this issue.  Otherwise prospective customers might not want to buy their products if there is a perceived danger that a charging system failure could stop the engine.

 Joe

 

  	  Quote: 	
		  This is not a perceived danger, as you

stated, but a real actual failure reported by more than 1 lister.  I

agree that the company should issue a statement to clarify their design

goals.  In the mean time, it appears that pilots should be aware of

this potential problem and the power to the Light Speed Ignition systems

should be fed through an easily accessible in flight circuit breaker.

[/b] 	
	


    This is one example of the important activities

    for crafting and qualifying systems on

    TC aircraft. This exercise offers decades of valuable

    lessons-learned. The conversations that have

    evolved around this topic are excellent examples

    of how much "wobble" there is moving toward

    complete understanding when we're not privy to

    the details of a particular product's design.



    On the TC side of the house it's not uncommon for

    an OEM airframer to have complete sets of drawings

    for as-supplied products in the "vendor files". 

    Of course, these are protected under the standard

    non-disclosure agreements. Access to these files

    is a critical component of seamless system

    integration and troubleshooting of fielded

    systems.



    Not having access to internal details gives rise

    to discussions not unlike those we're having now

    about Lightspeed . . . and those we've had in the

    past about critical characteristics of IR

    alternators.



    The point I've emphasized in all of these

    discussions is that intimate knowledge of the

    inner workings of a product is absolutely required

    for competent systems folks to do their job.

    The marketing hype and 4-color brochures are

    useless when it comes to qualifying a device on the

    aircraft and/or preventing/fixing problems in the

    field.



    There is risk when a customer is forced to

    "interpret" the meaning of words to arrive at some

    rudimentary understanding. Lightspeed has a

    free-marked duty to give you lucid answers to

    all of your questions . . . just as you have

    a right to reject their product based on

    perceptions of value and risk. Risk pushed

    upon you as a product of holding critical details

    incommunicado is not acceptable.



 

        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------



     [quote][b]

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user9253

Joined: 28 Mar 2008
Posts: 1923
Location: Riley TWP Michigan

Posted: Sun Feb 08, 2009 5:58 pm Post subject: Re: Light Speed Ignition with OV

Thanks to Bob and Roger for the informative replies.



Roger, You mentioned other postings about over-voltage conditions disabling the Lightspeed ignition.  I would like to read about them if you happen to have a link to the posting.  I do not read AeroElectric everyday and missed the postings.  I did read about a Lightspeed ignition that failed because of overheating.

Thanks, Joe

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_________________
Joe Gores

mrspudandcompany(at)veriz
Guest

Posted: Mon Feb 09, 2009 6:14 am Post subject: Light Speed Ignition with OV

 	  Quote: 	
		   Thanks to Bob and Roger for the informative replies.



 Roger, You mentioned other postings about over-voltage conditions 

 disabling the Lightspeed ignition.  I would like to read about them if you 

 happen to have a link to the posting.  I do not read AeroElectric everyday 

 and missed the postings.  I did read about a Lightspeed ignition that 

 failed because of overheating.

 Thanks, Joe


	




Joe,



I have erased most of the recent postings, but here is one in which Bob 

gives a lot of info:



Roger




<nuckolls.bob(at)aeroelectric.com>



At 11:34 AM 2/4/2009, you wrote:

 	  Quote: 	
		  Bob,



If I choose the routed suggested by your diagram

to run both ign boxes, would you duplicate the

fuse & 14 AWG from the batt buss or simply run

the 14 AWG to a bus bar such that I could hook up both 5 amp cb's?


	


   If you create an ignition bus that services

   contemporary conventions for minimizing the energy

   exposure of battery-feed wires during crash

   events, then you need a disconnect at the battery.

   A design goal for inoculating the aircraft's

   accessories from single-points of failure becoming

   hazardous.



   This suggests that dual ignition systems are either

   powered from multiple busses that have low probability

   of common failure or a single bus with a VERY low

   probability of failure.



   We've cited design and maintenance goals for making

   sure that a battery bus connected to a well maintained

   RG battery is the single bus with a very low

   probability of failure.



   This gave the writer comfort in suggesting that

   separate fuses for two ignition systems fed from

   an always hot bus supported was a good design

   when that bus was supported by (1) well maintained

   RG battery (2) main alternator (3) aux alternator

   and (4) protected with very fast fuses that addressed

   our goals for crash safety.



 	  Quote: 	
		  It appears that this is only adding hardware

from the already existing entry point of the

buss and further extending it to cb's. The only

valid argument I see is the ability to reset a

cb in crisis mode (after a big OV event has

blown both fuses) and continue down the road -

albeit with just about everything  else riding on the buss blown as well.


	


   That's the real sticking point. If we're doing due

   diligence and honoring our past teachers, there's no

   reason for the ignition system to even have such a

   feature. No mater how honorable the motivation for

   including it, it created FEMA issues that would

   get the thing booted from a TC aircraft.



 	  Quote: 	
		  

Thanks so much for your input on this topic. I'm

sorry you are not getting paid for this prime

time activity. Hopefully there is a way we can donate to your cause.


	


    I wouldn't do it if it were not useful to me

    personally . . . so don't be concerned for any

    overt lack of compensation . . .



 	  Quote: 	
		    Recently I read a thread from some FAA lawyers

 who were talking about mechanical standards and

 regulation. One said that the FAA regulations

 for mechanical compliance (not design) are

 designed to be debated. He was referring to the

 often vague terms in which the regulations are

 written. They should be left open enough for

 debate, but not too wide open as to allow broad

 deviation from normal practices (depends who's calling what normal).


	


    Gee do they think? Do you suppose this is why

    folks in the airframe services business will shop

    around for the most compliant ACO to get their

    STC or 337 on an airplane? Like our tax codes,

    the FARS are a study in debate prompted by a

    lack of teaching to simple-ideas.



    The same phenomenon is infecting industry and

    government with an MBA/Harvard-Law mentality that

    curiosity, creativity and wisdom of experience

    by honorable individuals can be replaced with

    "The Plan".

 	  Quote: 	
		  

IMO this type of debate should strive to improve

the quality/design of the products offered in

such a way that the improvements are both

advantageous in technological design and add a

factor of safety for the end user. For my $$

pure technology advancement that adds little or

takes away from the integrity of well known systems is a bad investment.


	


    Absolutely.

 	  Quote: 	
		  

So, debate is good and I hope Klaus and others

accept the forward thinking on which their products are offered.


	


    Sure. I recall with great fondness the circumstances

    of my last really rewarding job. I cannot recall a

    single instance of walking with trepidation into

    a come-to-jesus meeting in Beech's Targets Division.

    We had many meetings were some portion of a program

    was in trouble. As the problem was discussed and

    ideas circulated around the table, new avenues of

    attack would emerge. Folks freely volunteered to

    help out. You always walked out of those meetings

    with a feeling of accomplishment and renewal. This

    is how I imagine the meetings in Kelly Johnson's

    "Skunk Works" worked.  This is a tribute to a handful

    of individuals at the ship's wheel.



    You can bet the bank on the idea that progress

    was bench marked by the successful integration of

    simple-ideas to satisfaction of design goals

    by a group of honorable individuals. That's my

    vision of what should happen here on the List.



    Bob . . .

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nuckolls.bob(at)aeroelect
Guest

Posted: Mon Feb 09, 2009 6:49 am Post subject: Light Speed Ignition with OV

At 08:02 AM 2/9/2009, you wrote:

 	  Quote: 	
		  

<mrspudandcompany(at)verizon.net>

>Thanks to Bob and Roger for the informative replies.

>

>Roger, You mentioned other postings about over-voltage conditions 

>disabling the Lightspeed ignition.  I would like to read about them 

>if you happen to have a link to the posting.  I do not read 

>AeroElectric everyday and missed the postings.  I did read about a 

>Lightspeed ignition that failed because of overheating.

>Thanks, Joe

Joe,



I have erased most of the recent postings, but here is one in which 

Bob gives a lot of info:



Roger




	


    AeroElectric-List messages are archived on the

    matronics.com server. You can search any of

    the matronics list at:



http://www.matronics.com/search/



    or review all postings of a particular time

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        Bob . . .



        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

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