Received-SPF: pass
 receiver=logan.com; client-ip=64.136.30.67; envelope-from=lm4@juno.com
To: flyrotary@lancaironline.net
Date: Wed, 24 Aug 2005 10:43:59 -0700
Subject: Re: [FlyRotary] Re: Fire extinguishers
Message-ID: <20050824.104400.3668.0.lm4@juno.com>
MIME-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
From: Lawrence E Mac Donald <lm4@juno.com>

As of yet, no one has come up with the notion of a 
lever (cable) operated set of doors that would block 
the air intakes of the cowling so that a fire 
extinguisher would work. 
Or is that a bad idea ?
Larry Mac Donald
Rochester N.Y.
Do not archive


On Wed, 24 Aug 2005 19:42:29 +1000 "Michael Burke"
<mburke@southernphone.com.au> writes:
> >the only way to keep the fire out is to keep the air out
> >being able to shut the cooling air flow, at the exit or intake will 
> help a
> lot.
> 
> I'm trying to put this in perspective.
> Assuming no way to shut off the intake air, is firing a halon 
> extinguisher
> in flight going to have ANY worthwhile impact on an engine fire? 
> Keep in
> mind that the fibreglass cowl is likely to be breached early on, 
> thus any
> control of airflow is lost. I'm beginning to think that the most 
> important
> issues here are detection, and removal of the source (fuel) and that 
> an
> extinguisher would be useful to save the plane once landed, but 
> worthless
> (and wasted) if used while airborne.
> 
> Thinking of fire makes me glad I built a pusher.
> John
> 
> Yes John, early detection is vital so a heat sensor, naked flame 
> detector is
> vital as is an ambient under cowl temp sensor. First one will detect 
> the
> fire, and the second one will tell you how hot things are getting, 
> and most
> important tell you when the fire has gone out.
>     The very best strategy is in aircraft design. You need cowl 
> flaps for
> BOTH inlet and air outlet points, so that you have total control of 
> the
> airflow through the cowl. There are two main reasons for this.
> 1) If you can control the air flow, you CAN control the fire, you 
> starve it.
> Believe me it works. Why do commercial kitchens have fire blankets.
> 2) When you fire off your halon extinguisher, you want to hold that 
> cloud of
> halon under the cowl for as long as possible. If there is no air 
> flow it
> ain't going any where fast, and secondly and most importantly as 
> long as you
> have that halon cloud under the cowl, there is a very low 
> probability of
> re-ignition. this can buy you very valuable time to find a safe 
> landing
> area.
>     Other design factors are, a decent size drip tray and hear 
> barrier
> between the fuel rail and the exhaust port outlets. Don't allow fuel 
> to drip
> or spray onto a hot exhaust. Second, shield the exhaust pipe/s from 
> shooting
> a hot flame onto any fibreglass surface. Easier said than done I 
> know, but
> if it can be done it should. Otherwise experiment with industrial 
> fire proof
> matting on the inside surfaces of your cowl.
>     An extinguisher that you can control, and that has enough 
> reserve so
> that you can fire off 50% to 60% initially, and then two or three 
> bursts
> three or four minutes apart. This tops up the level of halon under 
> the cowl,
> and buys you very valuable time.
>     Fires can be managed, but like everything else, its a lot easier 
> if you
> design for them in the first place, and have a sound fire drill to 
> put into
> action.
> Safe flying guys
> Michael Burke
> Australia
> 
> 
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>