|
|
Hi Brad, Welcome to the list.
I'm a newbie here myself. I just chime in when I feel strongly about
something, as in this case. Fighting fires was something I sometimes I did
for a living.
Yes you are correct about putting the aircraft into a dive to blow the
fire out. But you are dealing with AIR COLLED engines, so they have to have
large holes in the cowling to cool them in the first place. Several problems
I see with this, not much good if you are flying VFR at 2000ft under the
weather, or flying at 2000ft VFR under controlled airspace in a built up
area. Secondly, even if you did manage to put the fire out in a dive, how do
you prevent it from re-igniting when you level out. Not mentioning all the
inherent problems of diving earth bound at speeds excedeing the VNE.
The point I'm making is this. The rotary is NOT air cooled, (directly
anyway)therefore we can take a different approach in designing the cowl. We
do not need a large volume of air blasting into the cowl, because the the
radiators can be set up so that they are ducted from the outside seperately.
Granted it is much harder to acheive in a pusher.
The one thing you must remember about a fire in a confined area is this,
if you block the air from getting in, the fire WILL go out. With that in
mind we design our rotary powered aircraft. Everything is imposible until it
is achieved. Nothing is achived until it is attempted.
Michael Burke.
Hi all:
I've never posted here before, and I'm not building a plane yet, but I
thought I'd comment on this for what it's worth (I'm planning on building an
RV-8A and I haven't decided on the engine to use yet).
All POHs for the certified planes that I've flown recommend a dive in case
of a cowling fire (and cutting any fuel fed into the cowling). These planes
obviously don't have any means to close off the airflow into the cowling.
But the fire suppression is accomplished by making the mixture too lean
within the cowling to support a fire, hence the dive. I think my old Mooney
recommended opening the cowl flaps too (it's been several years).
It would seem to me that it would be much harder to seal a cowl, especially
since the cowl material is not likely to be very fire-resistant, than to
blow the fire out, so to speak, by allowing a bunch of air in to make it too
lean to burn.
I presently fly an Aerostar, which has fire detectors installed. I
understand that they can give false fire alarms, but that this is fairly
rare. In any event, I still have another engine running if I shut one down
due to a false alarm.
Brad Gould
From: "Michael Burke" <mburke@southernphone.com.au>
Subject: Re: [FlyRotary] Re: Fire extinguishers
Date: Thu, 25 Aug 2005 16:05:05 +1000
Hi Larry,
I was thinking of the new streamline cowls that has one large opening at the
six o clock position. With the cooling rads slung under the engine, they can
be ducted through to the exit cowl at the rear. My idea, (probably many ways
to do it) would be to take the air for the engine compartment through an
opening at the top of the duct just inside the duct inlet. This opening
could then be controlled by a seperate flap, actuated from the cabin by a
push/pull cable that can be locked in both positions. I would imagine this
opening would not have to be very big, and if positioned properly should not
interfere with air to the cooling rads. It would give one the ability to
block inlet air to the engine without affecting the rads. The rads ducting
would have to be pretty airtight as would the cowling around the spinner.
That's the approach I'll be taking FWIW.
Michael Burke.
Australia.
Larry,
If you block both intake and outlet, the fire should die or be reduced to
nothing. Fire extinguisher on top will put it down.
On Aug 24, 2005, at 1:43 PM, Lawrence E Mac Donald wrote:
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
----------------------------------------------------------------------------
----
Michael Burke
|
|