[Land-speed] Fire alarm lite

Benn karhu at california.com
Thu Dec 20 15:48:55 MST 2007

Hmm, aren't the flames just invisible to our eyes?  Why couldn't a sensor 
respond to IR frequencies?  Yeah, it would take careful aiming to avoid 
being triggered by a hot exhaust or something, maybe with a time-averaged 
signal involved (sorta like security light sensors).   And can one assure 
that smoke in an engine compartment would pass through a smoke detector?  On 
a see-dan, I'd think air currents could be going all over the place at 200 
mph--I suppose a streamliner with a fully buttoned-up compartment wouldn't 
present that problem.

----- Original Message ----- 
From: "Rick Byrnes" <Rick at RBMotorsports.com>
To: "Bob Williams" <bob at arrowracing.org>; "land speed list" 
<land-speed at autox.team.net>
Sent: Thursday, December 20, 2007 12:37 PM
Subject: Re: [Land-speed] Fire alarm lite

> Hi Bob
> I should have been a little more explicit in my first note.
> The automatic fire bottle is in addition to manually activated bottles. 
> In
> my car there is another 30 pounds and on the Ford Fusion I had an 
> additional
> 20 pounds that I control with manual cables, just like always.  The light
> tells me the first bottle went off automatically and I drive to emergency
> side of the course and bail if its still on fire.  Of course after setting
> off the second bottle for the engine bay, or the third bottle if I can 
> feel
> fire as far forward as I am.
> I have practiced the drill many times in preparation for this past season 
> as
> I have an inordinate fear of fire.
> Relative to the Orbis smoke detector, I do not know if it is the best, but
> in the enclosed space of the car, it is enough.
> Also, the chances of a false alarm with smoke detector is much better than
> with the IR and UV sensors.  Some real aerospace type of sensors get much
> better, but still have some incidence of false alarm.  The cheaper the
> sensing system, the more potential problems with false alarms.
> The use of smoke sensor was a pretty comfortable move for me, in addition 
> to
> more than half a dozen H2 sensors set at very sensitive levels.  On one 
> run
> we got shut down because one of these sensors picking up a minute amount 
> at
> the rear of the car.  The guys replumbed the exhaust outlet and no more
> problem.
> I think I would suggest some additional research to make sure you can be
> happy with whatever sensor you choose.
> The logic of smoke sensor when flames may be almost invisable seems really
> good to me.
> Rick
> _______________________________________________
> karhu at california.com
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