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Momentary start power switch or not?

in 912iS Technical Questions 9 years ago

  • Re: Momentary start power switch or not?

    by » 9 years ago

    ...My aircraft is likely to have to be parked on low-security airstrips for much of the time and there are weird people who like to "meddle" with aircraft. I need to be sure that it is not possible to start the engine without unlocking something!...


    Be careful that you do not compromise reliability in the name of security.

    The Battery Backup Switch should bypass the Battery Solenoid/Switch.
    If the idiot is crazy enough, I suppose that operating the Backup Switch and hand propping the engine just might start it.
    Otherwise, your battery is likely going to be dead after the tampering incident.

    The marine industry has a similar problem.
    There are Manual battery disconnect switches rated for 100's of Amps installed near the battery where you take a removable giant plastic key with you for security.
    Only you know where the Switch is located in the engine compartment.
    It won't stop James Bond, But it will confuse the average idiot.

    Google; Marine Battery Disconnect Switch.

    BatterySwitch.jpg (You do not have access to download this file.)

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

      
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  • Re: Momentary start power switch or not?

    by » 9 years ago

    [quote]If it weren't, how would you restart the engine after a dual Gen failure? [/quote]
    Correct, but normally the start-power would be off during flight so it is best to ask the question.
      
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  • Re: Momentary start power switch or not?

    by » 9 years ago

    Bill or Geoffrey; can you provide a drawing of your idea?
      
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  • Re: Momentary start power switch or not?

    by » 9 years ago

    There is nothing ground breaking here except for the selection of a unique switch.
    Geoffery has selected a 4 pole switch, but a 2 pole would do the job just as well. (MS27407-5)
    It would be an otherwise common 2 pole, double throw Switch except it has three positions and designated an ON-ON-ON Switch.



    In the DOWN position both Common Terminals connect to the Lower Outputs.
    In the UP position, Both Common Terminals connect to the Upper Outputs. All as expected.

    In the Center Position,(Pay Attention!)
    The Left common Terminal transfers to the Upper output,
    While The Right Common Terminal remains connected to the Lower Output. (Not a Common Arrangement)

    This allows DOWN to be Both OFF
    CENTER Enables START POWER
    UP Enables START POWER and the STARTER.

    All very neat and intuitive!
    DpdtSwitch.JPG (You do not have access to download this file.)

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

      
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  • Re: Momentary start power switch or not?

    by » 9 years ago

    I think a 4 pole is necessary, the start-power requires 2 poles by itself.
      
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