Engine Fire

[Stifler's Mom]

Ah geez, the dog with the goggles has logged onto FN FAL's computer again.

 

[FN FAL]

Ah geez, the dog with the goggles has logged onto FN FAL's computer again.

Hahaha...Bow wow wow, yippie yo, yippie yea!

 

[A Squared]

i do see ur point, its funny how it is called an engine fire, but really the engine will probably never catch on fire, the only TRUE engine fire is when the metal catches fire... which i'll bet alot of money that its never happened with a recip...

Nope, not true. Many recip engines contain quite a bit of magnesium, which burns really really well once you get it going and is very difficult to extinguish, almost impossible. And yes, the magnesium does catch on fire occasionally.

 

[TIS]

Nope, not true. Many recip engines contain quite a bit of magnesium, which burns really really well once you get it going and is very difficult to extinguish, almost impossible. And yes, the magnesium does catch on fire occasionally.

Yeah, but the alloys used in engines are dumbed down pretty good for exactly the reason you're referring to. About the only time it'll catch is if there's a MUCH bigger fuel fire around it - like after a crash.

 

[avbug]

Actually no...metal isn't dumbed down at all, can't be. The alloys in many light recip engine cases are largely magnesium, and yes, they do make great class D fires.

What makes a fire hot enough to go there? How about a forced air fire? Like, say, what happens in an aircraft in flight?

Never seen burned and melted components in an engine compartment? I surely have, with spatter all over the place. Get a good oil or fuel fire going up there and don't control it, you could have a real problem, including a class D fire.

 

[A Squared]

About the only time it'll catch is if there's a MUCH bigger fuel fire around it - like after a crash.

No, not true, I know of several which happened in flight. At least one was an accessory section on an R2800 which resulted from a bearing failure and burned from the inside out.

 

[Milkdud99]

now im no expert on metal, BUT i would think that the engines were made of a metal that would be hard to ignite.

 

[darkvw]

next time you are out in the middle of a BIG field , clear off a BIG area and then start a small fire. Get a half engine case from an old VW ( they are about the same as the lycoming ) then throw it in the fire, be prepared to get to visit the local firemen too.

 

[TurboS7]

Avbug took care of all the technical stuff. Yes, many at start-up serveral in the air. Friend had a real serious one in the Aztec, like if he hadn't shut the engine down NOW in 30 seconds he would have been a fireball.

 

[wxman13]

Speaking of fires on startup, since these sound like they can be very serious...

Most aircraft emergency checklists that I've seen (single engine pistons) call for continued cranking on a fire at startup, then mixture idle/cutoff, fuel off, etc. How effective is that sequence in reality, versus just shutting off the fuel, turning off the ignition, and running far from the plane?

Peter

 

[TIS]

Actually no...metal isn't dumbed down at all, can't be. The alloys in many light recip engine cases are largely magnesium, and yes, they do make great class D fires.

What makes a fire hot enough to go there? How about a forced air fire? Like, say, what happens in an aircraft in flight?

Never seen burned and melted components in an engine compartment? I surely have, with spatter all over the place. Get a good oil or fuel fire going up there and don't control it, you could have a real problem, including a class D fire.

No, not true, I know of several which happened in flight. At least one was an accessory section on an R2800 which resulted from a bearing failure and burned from the inside out.

I know, I know. But you guys are talking about big, multi-bank radials and that's not what my original answer was referring to at all - and I think you both know, or should know that. The guy who asked the original question is a long ways from needing to know anything about big radials. I doubt he's ever seen one perform at top end at Reno.

You simply don't get Class D fires in light recips that often - PERIOD! The reason? Continental and Lycoming DON'T use Mg for their crankcases! Yup, that's right - it's an aluminum alloy. I guess that explains why you can WELD a cracked crankcase on one of these engines, huh?

In the past some cases on light recips were made of Mg and I suppose there are a few still drifting around out there but they're being replaced - for a reason. I don't buy the assertion that the majority of light recip engine cases are made of Mg. It's just not true.

Now, you can make aluminum burn under the right conditions but you generally can't establish those under the cowl of a flying Cherokee.

 

[Crimson03]

For the vw engine in a field trick I believe it has to be a vw bus engine, don't think the bug engines were magnesium. The bus I saw burn was mg.

 

[darkvw]

all of the aircooled ones were an alloy of aluminum and mag, any of them work , not that I would know from trials hahahahahah, but you don't want more than half a case at a time

 

[Milkdud99]

Speaking of fires on startup, since these sound like they can be very serious...

Most aircraft emergency checklists that I've seen (single engine pistons) call for continued cranking on a fire at startup, then mixture idle/cutoff, fuel off, etc. How effective is that sequence in reality, versus just shutting off the fuel, turning off the ignition, and running far from the plane?

Peter

worked with my 64 vette.....

 

[avbug]

I was talking about horizontally opposed reciprocating piston engines...found in light airplane engines.

In typical oil analysis, magnesium in a lycoming engine comes from two sources; the sump on some engines, or the magneto housing. Case wear is not normally an issue.

Even lycoming turbine engines were made from magnesium, excepting the marine engines, which were made from aluminum...not to prevent class D fires, but for corrosion protection.

Many light aircraft cases are mag cases, not all cases are weldable or repairable, and yes, cases and other components do burn. How is it that you admit that a fuel fire on the ground can burn a case, but you seem hesitant to believe one will burn in a forced air fire in flight...which burns faster, hotter, and is subsequently more intense...and dangerous? Of course they burn. There may not be as much time...but a class D fire can certainly occur in flight from engine materials, and it will generally burn furiously and all the way to the ground.

After that, it doesn't really matter any more, does it?