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Date: Wed, 13 Jan 2010 12:15:01 -0500
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Subject: Fire Extinguishers
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Valin -

We had a Halon fire extinguisher in each engine compartment of the Javelin=
 (FJ-33 jet engine).  The tanks were spherical and surprisingly small, lar=
ger than a grapefruit but smaller than a volleyball.  I think they had 3=
 pounds of extinguishing agent (Halon) in each.  It was understood that th=
is was way more than we needed, and I recall that we were looking for abou=
t one pound per engine for the production version.  These are not precise=
 recollections but is is enough to tell me that your proposed system is mo=
re than adequate as far as total quantity of Halon is concerned.

The ball had one exhaust port which was triggered by electrically firing=
 a pyrotechnic burst disk.  There was a manifold attached to the exhaust=
 port which directed the extinguishing agent to two places.  One was aimed=
 at the engine accessories (fuel pump, oil pump, etc) which were near the=
 bottom center of the engine, and the other was aimed near the top front=
 of the compartment.  I do not recall a fire extinguisher nozzle which act=
ually squirted the stuff into the engine air flow.

This was set up by someone way more knowledgable than myself.

The take home message for me, which I am passing on to the group, is that=
 3 pounds is way more than enough to put the fire out.  Also, that you pro=
bably want to concentrate the Halon in the areas where fire is likely to=
 be fed.  I think that if you put one nozzle above the engine, as in betwe=
en the cooling air inlets and the cooling fins, then you can put out anyth=
ing that is burning between the engine and the top of the cowling.  Of cou=
rse, there is not much to burn there (there is one fuel line there on my=
 engine).  I would direct a second nozzle to the accessory area behind/und=
er the engine.  I don't know about the 540 engine but the 320/360 has a lo=
t of tubes with flammable liquids between the engine and the firewall, fro=
m bottom to top of the engine compartment.  This is stuff like fuel pumps,=
 oil coolers, oil filters, etc.  I think that area is the most likely area=
 for a fire to break out.

I think it would be hard for Halon to get from the area above the engine=
 to the area behind and above the engine, and vice versa.  That's why two=
 nozzles are desirable.  We did not have a nozzle per se -- it was simply=
 the open end of a tube.

The other guys are right.  Once you put the fire out, you need to make sur=
e it won't start up again.  On the Javelin the fire extinguisher handle wo=
uld shut off fuel lines and engine bleed air lines before firing the extin=
guisher.  (We just used the other engine to come home...)  We would pull=
 the handle to shut off the fuel lines, then rotate it to fire the extingu=
isher if the fire did not go out just by turning off the fuel.

On our airplanes, all we can do is shut off the fuel heading into the engi=
ne compartment and hope for the best.

Along these lines, we have pretty good designs for keeping engine fumes fr=
m entering the cockpit, except for the cabin heat.  It would be bad to put=
 out the fire and then asphixiate (sp?) by inhaling Halon which entered th=
e cockpit from a cabin heat SCAT tube that just burned up in the engine co=
mpartment.  I don't know about you, but if there is an engine fire I proba=
bly won't remember to turn off the cabin heat.  No recommendation here --=
 just food for thought.

One final note -- the shop floor foreman had built many airplanes at the=
 Lockheed Skunk Works.  He looked at the pyrotechnic actuation system and=
 bet me that there was no way we would finish the project without accident=
ally popping off one of the extinguishers.  In fact, we did not (he still=
 owes me a seven-adjective Starbucks drink) but it tells me that odds are,=
 if you have a pyrotechnic system you are likely to accidentally actuate=
 it.  As a NASA rocket scientist you probably are more aware of how to kee=
p this from happening than the average Lancair builder but I caution you=
 to be careful with your electric actuation system.  It shouldn't hurt you=
 if it goes off as long as you can keep the Halon fumes from getting you,=
 but it would be an exciting day,  A cable actuation system would not be=
 a bad idea here.

Best of luck.  The engineering of your stuff is always top-notch and I loo=
k forward to seeing what you end up with.

- Rob Wolf


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<font color=3D'black' size=3D'2' face=3D'arial'>
<div>Valin -</div>


<div>&nbsp;</div>


<div>We had&nbsp;a Halon fire extinguisher in each engine compartment of=
 the Javelin (FJ-33 jet engine).&nbsp; The tanks were spherical and surpri=
singly&nbsp;small, larger than a grapefruit but smaller than a volleyball.=
&nbsp; I think they had 3 pounds of extinguishing agent (Halon) in each.&n=
bsp; It was understood that this was way more than we needed, and I recall=
 that we were looking for about one pound per engine for the production ve=
rsion.&nbsp; These are not precise recollections but is is enough to tell=
 me that your proposed system is more than adequate as far as total quanti=
ty of Halon is concerned.</div>


<div>&nbsp;</div>


<div>The ball had one exhaust port which was triggered by electrically fir=
ing a pyrotechnic burst disk.&nbsp; There was a manifold attached to the=
 exhaust port which directed the extinguishing agent to two places.&nbsp;&=
nbsp;One was aimed at the engine accessories (fuel pump, oil pump, etc) wh=
ich were near the bottom center of the engine, and the other was aimed nea=
r the top front of the compartment.&nbsp; I do not recall a fire extinguis=
her nozzle which actually squirted the stuff into the engine air flow.</di=
v>


<div>&nbsp;</div>


<div>This was set up by someone way more knowledgable than myself.</div>


<div>&nbsp;</div>


<div>The take home message for me, which I am passing on to the group, is=
 that 3 pounds is way more than enough to put the fire out.&nbsp; Also, th=
at you probably want to concentrate the Halon in the areas where fire is=
 likely to be fed.&nbsp; I think that if you put one nozzle above the engi=
ne, as in between the cooling air inlets and the cooling fins, then you ca=
n put out anything that is burning between the engine and the top of the=
 cowling.&nbsp; Of course, there is not much to burn there (there is&nbsp;=
one fuel line there on my engine).&nbsp; I would direct a second nozzle to=
 the accessory area behind/under the engine.&nbsp; I don't know about the=
 540 engine but the 320/360 has a lot of tubes with flammable liquids betw=
een the engine and the firewall, from bottom to top of the engine compartm=
ent.&nbsp; This is stuff like fuel pumps, oil coolers, oil filters, etc.&n=
bsp; I think that area is the most likely area for a fire to break out.</d=
iv>


<div>&nbsp;</div>


<div>I think it would be hard for Halon to get from the area above the eng=
ine to the area behind and above the engine, and vice versa.&nbsp; That's=
 why two nozzles are desirable.&nbsp; We did not have a nozzle per se --=
 it was simply the open end of a tube.</div>


<div>&nbsp;</div>


<div>The other guys are right.&nbsp; Once you put the fire out, you need=
 to make sure it won't start up again.&nbsp; On the Javelin the fire extin=
guisher handle would shut off fuel lines and engine bleed air lines before=
 firing the extinguisher.&nbsp; (We just used the other engine to come hom=
e...)&nbsp; We would pull the handle to shut off the fuel lines, then rota=
te it to fire the extinguisher if the fire did not go out just by turning=
 off the fuel.</div>


<div>&nbsp;</div>


<div>On our airplanes, all we can do is shut off the fuel heading into the=
 engine compartment and hope for the best.</div>


<div>&nbsp;</div>


<div>Along these lines, we have pretty good designs for keeping engine fum=
es frm entering the cockpit, except for the cabin heat.&nbsp; It would be=
 bad to put out the fire and then asphixiate (sp?) by inhaling Halon which=
 entered the cockpit from a cabin heat SCAT tube that just burned up in th=
e engine compartment.&nbsp; I don't know about you, but if there is an eng=
ine fire I probably won't remember to turn off the cabin heat.&nbsp; No re=
commendation here -- just food for thought.</div>


<div>&nbsp;</div>


<div>One final note -- the shop floor foreman had built many airplanes at=
 the Lockheed Skunk Works.&nbsp; He looked at the pyrotechnic actuation sy=
stem and bet me that there was no way we would finish the project without=
 accidentally popping off one of the extinguishers.&nbsp; In fact, we did=
 not (he still owes me a seven-adjective Starbucks drink) but it tells me=
 that odds are, if you have a pyrotechnic system you are likely to acciden=
tally actuate it.&nbsp; As a NASA rocket scientist you probably are more=
 aware of how to keep this from happening than the average Lancair builder=
 but I caution you to be careful with your electric actuation system.&nbsp=
; It shouldn't hurt you if it goes off as long as you can keep the Halon=
 fumes from getting you, but it would be an exciting day,&nbsp; A cable ac=
tuation system would not be a bad idea here.</div>


<div>&nbsp;</div>


<div>Best of luck.&nbsp; The engineering of your stuff is always top-notch=
 and I look forward to seeing what you end up with.</div>


<div>&nbsp;</div>


<div>- Rob Wolf</div>


<div><br>
<br>
&nbsp;</div>


<div style=3D"CLEAR: both"></div>
</font>

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