I have a question (actually two) about jet engines and aircraft carriers, actually, and I know there are lots of people here who know lots about those. I can't say why this came up, unfortunately, because it would violate board rules. :-)

The first question is about something called "wet starting" an engine. I've seen it but have no question what it means. Can anybody explain what it is?

The other question is, do pilots "wet start" engines on aircraft carriers? Is it something dangerous to do?

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As above, so below

I'm not sure about jet engines, but a "wet start" is when you allow fuel to pool a moment before igniting it. Makes a nice Bang.

In this case, most likely the pilot would pool kerosene within the engine and then ignite, causing a helluva exhaust plume. I am guessing here.

I imagine the prank could be dangerous. I don't know if it's practiced these days, but I have heard of it happening on carriers.

Most likely in these times, doing it would get the pilot drummed up.

Hmm, this wouldnt have anything to do with GLP would it?

What those crazy folks do on carriers, I don't know. But letting fuel pool in an engine and then lighting it is a bad thing in the civilian world. It will at least shoot a flame and possibly explode. Maybe carrier pilots do it or used do it, but I'd like to think they are a bit more cautious than that.

That said, it's been done accidently by say motoring the engine, opening the fuel valve and then remembering that you forgot to turn on the ignitors or one system is failed. What you're supposed to do is close the fuel and motor the engine and start over. What's been done is reaching up and flipping the ignitor switch on or to the other system and boom.

I once did a manual start on a 727 where they were slow getting the fire lit. It shot a pretty impressive flame out the back with me and another guy standing next to it on a lift truck. It was dark too so it was even more impressive. Good times.

EDIT: I see neverfly beat me to it. That's what I get for being wordy.

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Nahh cuz I was guessin'

But I'm curious... What would GLP have to do with the OP?

Actually, I've never deliberately visited that site before. But I just found it. And yes, it is somehow related. I saw it somewhere else, though. It seems like a pretty flimsy idea. But I was kind of surprised that I couldn't find any simple information on wet-starting on the Internet. It's so full of information, you'd think it would be easy to find.

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As above, so below

Maybe your Google Search Filter is On.

"wet start"


Sounds kinda naughty....




OKokokok actually I just tried googling it too and didn't come up with squat. Found something that mentions McCain and an incident involving a wet start. But it didn't say what a wet start WAS....[ETA: This sounded naughty too... Maybe I should have worded it differently...]

I Googled GLP Wet Start and got a description of the incident that included what a we start was. And yeah, in the context given. This is not the place.

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I'm not gullible because I'm a Leo.--Actually said to me by a co-worker
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The difference between planning and pessimism can only be seen in retrospect. -- One of mine
Truth ain't like puppies; a bunch of them running around and you get to pick the one you like best." -- Emerson on Pushing Daisies

Jens, I'm speculating that the folks at GLP or where ever you encountered this question are focusing on the large flames that can sometimes be seen from aircraft taking off from carriers. There is a more basic expalnation than "wet starting" whatever that may be. It's the afterburners. When a plane takes off from a carrier the catapult only provides a portion of the necessary force. The rest comes from the plane's engines. Before the cat shot they ramp up to full power, inlcuding afterburner in some cases. This causes a large "flame" to shoot out the back end. It's quite impressive at night (I've seen it) especially from the old F-14's (now retired sadly).

Although I've ridden many carriers in the course of my job, you might ask Big Don who actually worked on carrier flight decks (and F-14's if I recall) about this.

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"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind." - William Thompson, 1st Baron Lord Kelvin

"If it was so, it might be, and if it were so, it would be, but as it isn't, it ain't. That's logic!" - Tweedledee

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Yeah, Big Don sounds like the one to know. I myself don't think I've ever actually heard the term wet start before. Hot start, hung start and maybe a few more but not that one. Maybe because it taboo. I googled it just to see if the term actually existed and found some navy war stories or something which I didn't read. And it's not in my aircraft techical dictionary, whereas hung start and hot start are. Maybe it's another internet term. Or a navy one. Oh well.

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I don't think pilots of modern fighter aircraft have that much control over engine startup any more.

....maybe back in Korea and Vietnam, but nowadays its all computer controlled so they DONT blow up an expensive time-consuming-to-replace engine.

If the claim that sparked the question is the one I think it is, it would have been a Vietnam era plane. In broad terms, it's that the blast of fire from a "wet start" was sufficient to "cook off" munitions on the plane behind it.

I find it hard to accept that a plane would be allowed to start if there was another close enough to reach with that, but I'm sure others (Don) can give a more official version of the rules.

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I'm not gullible because I'm a Leo.--Actually said to me by a co-worker
Never trust anyone with 'The' for a middle name. --Said to me by a guy in Denny's at 4 am.
The difference between planning and pessimism can only be seen in retrospect. -- One of mine
Truth ain't like puppies; a bunch of them running around and you get to pick the one you like best." -- Emerson on Pushing Daisies

Quick! Activate the BigDon signal!

Yes, that's right, an A-4 actually. Piloted by. . . Oops, can't say that! I also found the story a bit hard to accept. There's actually some footage from the incident on youtube, and it looks (to my non-professional eyes) like the A-4s are positioned so that the engine exhaust ports are pointed off the deck.

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As above, so below

That's what I see as well, but what I wasn't sure about was if the engines were started there and the plane taxied to the cats, or if they were dragged there by one of those little trucks, then started closer to the flight line.

Either way, I just can't see a blast from the engine producing enough heat for a long enough duration to "cook off" a rocket motor.

__________________
I'm not gullible because I'm a Leo.--Actually said to me by a co-worker
Never trust anyone with 'The' for a middle name. --Said to me by a guy in Denny's at 4 am.
The difference between planning and pessimism can only be seen in retrospect. -- One of mine
Truth ain't like puppies; a bunch of them running around and you get to pick the one you like best." -- Emerson on Pushing Daisies

If you're talking around the Forrestal fire, a Zuni rocket from an F-4 accidentally fired while the plane was on the flight deck. It flew across the flight deck and struck the A-4 that John McCain was sitting in. He was lucky to survive. I saw a program recently where an investigator tried to determine why the rocket fired. IIRC, the investigator believes there was a wiring malfunction in the F-4.

There was another fire on a carrier in the 1960s where a ground start cart (I think it was called a huffer) was parked too close in front of a plane. The huffer's exhaust blew directly on the plane's munitions (many of them dating back to WWII) and cooked off an explosition.

It sounds like someone is combining elements of the two fires. Whether they're doing it innocently or to make political remarks about McCain, I don't know.

Very much the latter.

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I'm not gullible because I'm a Leo.--Actually said to me by a co-worker
Never trust anyone with 'The' for a middle name. --Said to me by a guy in Denny's at 4 am.
The difference between planning and pessimism can only be seen in retrospect. -- One of mine
Truth ain't like puppies; a bunch of them running around and you get to pick the one you like best." -- Emerson on Pushing Daisies

Then they are full of the stuff that makes things grow. The Forrestal fire was very intensely investigated. I've seen the video. I'm no fan of John McCain but this kind of character assassination is very low.

I really agree. I'm also not a fan of McCain (I'm actualy a fan of a different candidate), but I think it's unfair to attack him for things that are unreasonable. It's just like the attacks on a different candidate for allegedly being a Muslim.

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As above, so below

I watch politics, and I've never heard anyone doing whatever it is that y'all say they're doing. (What is it, blaming him for a fire nobody's ever even heard of?)

If that were what someone's trying to do, it would make more noise.

Folks, a "wet start" is caused by either an improperly aligned fuel selector, or the pilot putting the throttles in the wrong position before starting the engine. It's simply too much fuel pooling in the burner cans before or during start (hence the "wet") and is characterized by long flames coming out the back.

The fix is to advance to full throttle, which blows the rest of the fuel out the back, burning the fuel.

A wet start is NOT an intentional procedure, and can be dangerous if it's not detected and corrected, and the correction can be dangerous, too, if someone is anywhere near the back of the engine!

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