[NSRCA-discussion] Arming Switch

Sun Feb 12 14:09:00 AKST 2012

I have personally observed someone turning off their RX and having the ESC go to full power, it was a smaller plane, but the APC prop managed to strike his arm 17 times (15 of which required stitches) before the system could be disarmed properly.   Forgive me Dave, but what you suggest is fundamentally dangerous. At a field in Ohio an electric powered 89" slick had the RX powered off, the impact on the pilot's legs knocked him over allowing the plane to run 30 feet uncontrolled into a picnic bench that was fortunately unoccupied at the time.  Granted, that's 5600 watts of power, not the 2500-3000 we run, but still...

Peter+

Sent from my iPhone4S

On Feb 12, 2012, at 3:01 PM, "Dave Harmon" <k6xyz at sbcglobal.net> wrote:

> Hi Keith….
> Actually I DID take into account that there IS a possibility that the ESC could fail….but I feel the odds of that happening are as I said, a lot less than someone mishandling a transmitter.
> How about just plugging the battery in and putting the canopy on within the 3 minute starting period??
> The airplane should not have to just sit there plugged in and ready to go like a fueled up glow powered airplane….
> After landing someone picks up the model and turns off the radio switch….if the helper picks up the airplane and the ESC malfunctions he has ahold of it.
> I understand your and others concerns but I just don’t think the external plug thing is necessary.  
> I just don’t see the need to have a battery in the plane unless it is manually restrained and going to be flown within the next 3 minutes.
> I don’t mean to imply that I plug in the battery without straddling the fuselage….I do!
>  
> Dave Harmon
> NSRCA 586
> K6XYZ[at]sbcglobal[dot]net
> Sperry, Ok.
>  
> From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Keith Black
> Sent: Sunday, February 12, 2012 4:29 PM
> To: General pattern discussion
> Subject: Re: [NSRCA-discussion] Arming Switch
>  
> Dave, you're points are correct, but you're not taking into account a malfunction of the speed controller itself. They have been know to malfunction, so the safest approach, as Earl suggests, is to assume that anytime the battery is connected to the controller the motor may go to full throttle. Until you unplug the battery the thing is hot and dangerous regardless of your fail safe or switches on the transmitter. 
>  
> Regarding pulling the disconnect (whether under canopy or via external arming pin), step over the model between wings and stab (just like we used to run up the glow models) and reach down to pull the plug. If it goes full throttle the back of your legs will stop forward momentum.
>  
> I see far too often that people switch off their radios with the plane in a potential dangerous position. This is putting a lot of trust in the technology when it's not necessary. When I retrieve my model,  transmitter in hand or not, I make sure it is pointed away from people or property.
>  
> Keith 
> 
> On Sun, Feb 12, 2012 at 2:28 PM, Dave Harmon <k6xyz at sbcglobal.net> wrote:
> +1 on that.
> Rather than having a disconnect, I think ensuring that the fail safe function of the radio is set properly is the way to go.
> Generally…with today’s 2.4g radios…..not 72mhz PCM radios….I trust the electronics more than someone holding the transmitter.
> Besides….with a disconnect it would be my luck to rip the side of the fuselage off and start a fire that way………or not being able to let go of a full throttle model to pull the disconnect….in this case just turn off the transmitter and/or have an external radio switch and turn off the receiver.
> The ESC will shut off the motor when the ESC loses the pulse from the receiver…even if the failsafe is NOT configured correctly.
> Everyone already knows this….or should know it…. but it’s a good thing to mention anyway…..
>  
>  
> Dave Harmon
> NSRCA 586
> K6XYZ[at]sbcglobal[dot]net
> Sperry, Ok.
>  
> From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Keith Hoard
> Sent: Sunday, February 12, 2012 1:44 PM
> To: General pattern discussion
> Subject: Re: [NSRCA-discussion] Arming Switch
>  
> I'd rather not cut a hole in my plane in the first place, or add another point of failure to the system. . . .
> 
> 
> 
> Keith Hoard
> Collierville, TN
> khoard at gmail.com
> 
> 
> 
> On Sun, Feb 12, 2012 at 1:37 PM, Ronald Van Putte <vanputte at cox.net> wrote:
> You can mount a female Deans connector in a piece of thin plywood, use Pacer Pro Zap to glue the Deans connector to the plywood and, after cutting an appropriate hole in the side of the fuselage, glue the assembly inside the fuselage.  Use a male Deans connector with the leads soldered together as an arming plug.
>  
> Or you can buy a SharpRC SafeArm (http://www.sharprc.com/catalog/index.php?cPath=43)
>  
> Being cheap, I do the former.
>  
> Ron Van Putte
>   
> On Feb 12, 2012, at 11:55 AM, Ron Hansen wrote:
>  
> What are the available arming switch options?
>  
> Thanks
>  
> Ron
> 
> 
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