[NSRCA-discussion] E-Safety idea (was: Re: Noxville Contest??)

Tue Aug 8 11:05:38 AKDT 2006

(note the bad e-maill addy I used below was the "Reply" button... I'm having to copy-paste the addy in from one specific e-mail to get my replies to go through correctly)

An in-line fuse and holder would have negligible resistance.  It is true that each connection... each switch, every milimeter of wire adds some resistance and thus "robs" power from the propeller... but the amount lost is so tiny as to have negligible effect. (less loss over a whole flight than the power used in 1/10 sec of slowly turning the prop for example)

A properly rated fuse holder, would be of inconsequential resistance.  The under-rated ones I am finding would have potentially significant resistance for the application.
A properly rated switch again would have inconsequential resistance.

The ratings of electrical switches and fuses are based on them having little to no effect on the circuit when they are installed. (if you use the correct components)

And... more resistance means LESS current CAN flow.  Not higher current draw... less useable power output.  
E=IR  Add reesistance.. Voltage is constant.. curent MUST be less.  But an electric motor is a variable resistance load...
  ----- Original Message ----- 
  From: Doug Cronkhite 
  To: 'NSRCA Mailing List' 
  Sent: Tuesday, August 08, 2006 1:46 PM
  Subject: Re: [NSRCA-discussion] E-Safety idea (was: Re: Noxville Contest??)

  Biggest issue there is anything inline in the circuit means more resistance and therefore higher current draw.

  -Doug

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  From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Fred Huber
  Sent: Tuesday, August 08, 2006 11:35 AM
  To: NSRCA Mailing List
  Subject: [NSRCA-discussion] E-Safety idea (was: Re: Noxville Contest??)

  What I would like to find is a fuse holder with an easy to insert/remove fuse (automotive blade type for example) of appropriate amp rating.  I can find 40 amp automotive fuses.  Highest rating fuse holder I have found is 20 amp.  My system pulls 25 amp continuous max throttle static, so the appropriate fuse is available... but not the holder.

  Pull the fuse... the motor's guaranteed dead.  and if somethig does happen where the prop is chewing an arm or foot, the current should blow the fuse (if its sized correctly) at least reducing the damage done.  A fuse would also potentially protect the power system  (those expensive lipos especially) in some crashes.

  I like the idea of an arming switch... but a fuse could do the same job and more.

  ***********

  Note... my understanding of a "deadman switch" is from how its explained for a modern desil locomotive... if the operator dies, he can't keep holding the switch and the locomotive is supposed to stop. (supposed to...)  Thus a deadman switch on a model would... stop the motor as soon as you let go.

  Maybe a misnomer is involved somewhere?

    ----- Original Message ----- 

    From: Dean Pappas 

    To: NSRCA Mailing List 

    Sent: Tuesday, August 08, 2006 1:16 PM

    Subject: Re: [NSRCA-discussion] Noxville Contest??

    I just received a first production item of a simple safety item called the JoneSwitch. It is a convenient deadman switch that screws into the side of your electric plane.

    Look to see releases in at least several magazines. Now you can walk out to the runway before arming your electric system.

    all the best,

    Dean

    Dean Pappas 
    Sr. Design Engineer 
    Kodeos Communications 
    111 Corporate Blvd. 
    South Plainfield, N.J. 07080 
    (908) 222-7817 phone 
    (908) 222-2392 fax 
    d.pappas at kodeos.com 

      -----Original Message-----
      From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Jim Stovall
      Sent: Tuesday, August 08, 2006 2:08 PM
      To: NSRCA Mailing List
      Subject: Re: [NSRCA-discussion] Noxville Contest??

      Electrics IMHO are way more dangerous than IC engines. I have a $35,000 right arm to prove it. Had one spontaneously start on me at the field while my  forearm was in the way. Chewed through my forearm clear to the bone, severing my artery, muscle, and ulnar nerve. Very messy. Took 2 years of surgury and therapy before I could fly again. Electric motors are more serious in that they draw more amps if they are impeded, in effect they try "harder" to overcome the force opposing it, like thumbs, fingers, and arms. Still fly electrics, but treat them very differently now......

      wgalligan <wgalligan at goodsonacura.com> wrote: 

      At least my OS wont spontaneously startup on its own.

      I have seen a few electrics majicaly start unattended and thankfully no fingers or arms were in the way. Both engines and motors are dangerous.

      And I do have some smaller electrics.

      Wayne

      ----- Original Message ----- 

        From: J.Oddino 

        To: NSRCA Mailing List 

        Sent: Tuesday, August 08, 2006 11:53 AM

        Subject: Re: [NSRCA-discussion] Noxville Contest??

        Another reason to go electric.

        Jim O

          ----- Original Message ----- 

          From: John Ferrell 

          To: NSRCA Mailing List 

          Sent: Sunday, August 06, 2006 9:38 AM

          Subject: Re: [NSRCA-discussion] Noxville Contest??

          I have an $8000 left thumb. They installed a couple of options while they were rebuilding. It warns of weather changes and also serves as an alarm clock (sometimes).

          I recommended that a student headed for a pro basket ball career give up RC until the career was behind him.

          John Ferrell    W8CCW
          "My Competition is not my enemy"
          http://DixieNC.US

            ----- Original Message ----- 

            From: BUDDYonRC at aol.com 

            To: nsrca-discussion at lists.nsrca.org 

            Sent: Sunday, August 06, 2006 11:10 AM

            Subject: Re: [NSRCA-discussion] Noxville Contest??

            About two years ago I got my finger in one It cut the right index finger off at the first joint. Wrapped the finger in a towel went to the hospital with the severed finger, three month's and $6000.00 later it was almost as good as new except it is still numb on the end. APC's show no mercy.

            Buddy 

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