Bailout, Bailout, Bailout

Well....One Down.  35 to go.

Weeks that is. 

This one was about as expected.  In a variation of a joke STxAR commented with a few days ago, we prepped 650 out of 975 new laptops in time for school to start and gave them to teachers who had had no laptops before, do we get called wonderful?  No we get greeted with "Where are MY laptops?  I can't teach without them." 

No, Ma'am/Sir, you can't teach.

But I digress....

I'm sitting here in my office on a lovely, albeit warming rapidly, Sunday morn, running several scripts that need running but which I can't seem to get to during the week. (Reread para 3 if you need to ask why.)  I was trying to think of what to post about this week, Sarge having stolen all the good stories and stuff.

I swear, he's like Google sometimes.  You know what I mean.  You click on a link that you are curious about and all of a sudden all the ads you see are talking about retirement stuff. (Beans! What did you thing I was looking for?).  So, I've been thinking about this post for a couple of weeks, and then Sarge writes one and put's this picture in it.

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My first thought was "He's done it again!"

Fortunately, his post wasn't about ejecting from an Airplane.  So that means the subject is still available.

I had done a little investigating prior to commenting recently about ejecting through the roof.  Specifically, I couldn't remember if the F-15 had a canopy piercer or not.  Typically the first thing that happens when ejection is initiated is the canopy separates.  Having it remain in place is a great impediment to your longevity. Long time reader VX had remembered a friend killed in an F-4 when the ejection seat fired due to an electrical malfunction and the canopy had not separated. 

Early systems would just open the canopy a bit and the wind would rip it off.  Somewhat crude but worked most of the time (most being the operative word).  However, as aircraft became more sophisticated, wind flow over the canopy was not necessarily guaranteed.  For instance in a tail slide, the air is rushing from back to front.  The canopy is not going to separate.

Yes, tail slides happen frequently in air to air.  Depending on the airplane, they are great fun (F-15) or pretty exciting (F-4). Not in a good way.

 Nowadays, most aircraft have some kind of explosive device to separate the canopy from the jet.  Two of the jets I flew had a backup system in case that fails.  If that were to happen in the T-38 or F-15 the first thing that would hit the canopy would be a reinforced part of the seat put there to shatter the canopy allowing the seat and pilot to go on about their merry way.

The Harrier dispensed with the canopy by having an explosive cord in the canopy itself which exploded destroying the canopy and the pilot and seat went through that.

Note the canopy frame behind the hole Source

Well, that was step 1 in a long multi-stepped process, so stay tuned next Monday for the next installment.

Beans! Just kidding! 

So, I'm having difficulty maintaining flight and have made a wise decision to return the aircraft to the taxpayers.

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Do I stand up, hook up and shuffle to the door?  Well, no.

The next thing that happens, typically within about a quarter second is, the rocket under my seat fires, lifting the seat, with me in it out of the jet.  At that point, at least with the ACES seat in the F-15 and many others, a computer assesses quite a few parameters and adjusts the rocket accordingly.

Some of those factors, include airspeed, altimeter, vertical velocity and attitude.

As far as airspeed is concerned, anything above 450K, you're going to ride the seat for a while til you slow down a bit.  By a bit, I mean a few seconds.  If you are on the ground, stopped and needed to eject, the seat will fire, and you will be in your chute within 2 seconds.  A nice capability.

If you were in level flight, inverted, 150' above the ground (AGL), the computer would work the gimbals on the rocket to fire in such a was as to right you and once headed away from the ground, kick you out of the seat then deploy the chute.

If you were at medium altitude and below 450k, you would ride the seat for about 6 seconds to get you slowed down and stabilized, then the seat releases would work and the chute would deploy. 

Remember, in times of stress, time seems to slow.  That 6 seconds, I've been told by a buddy that jumped from an Eagle under that mode, seemed like forever.  He said he'd wondered if the seat had failed and he was riding it in at least a dozen times.

The most dangerous set of circumstances is a high speed dive.  The chart below is from my F-4E Dash-1.  The bible as far as a Fighter Pilot is concerned.  Certain sections were, in fact, memorized verbatim.  The rest were studied, reviewed, discussed, tested and digested until memorized.

So, if I'm in an F-4 in a 60^o dive doing 600K and take a hit, and decide to bailout, communicating those immortal words "Bailout, Bailout, Bailout" and pull the handle initiating the WSO's bailout followed 2 seconds afterwards by my seat firing, I have to have pulled the handle about 4200' above the ground.    Even a 15^o dive at that speed requires more than 1000'. 

The Eagle's ACES II seat was slightly better, but Physics is Physics, you're rushing at the ground at a great rate and the seat only functions at a fixed rate.  If the time to hit the ground is less than the time to open the chute, well........

But, time marches on and I came across this Article from Aviation Leak Week regarding improvements to the seat.  Basically, they improved it so it had a higher safe operating speed, 600K.  They also made it so things mounted on the aircrew helmet (e.g. night vision goggles etc) wouldn't interfere with the seat's operation. Also, at least for me, they made it handle big boys.  It will now handle up to a 245 pound pilot.  (only 5 more to go juvat, you can do it!)

No, I was well under that while I was flying, thanks for asking.

I found a couple of other interesting facts from this site .  I'd thought Ejection seats were a post WWII phenomenon.  Apparently the first one was built in 1910 and the Germans perfected one in time to have a combat ejection in 1942.

Reader "a bear" will undoubtedly comment about this, but apparently, the B-58 ejection system was tested using bears to ride the seat. 

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Research did lead me to one fact I thought was a bit disturbing.  The ACES II seat has a 94.4% success rate.  Which sounds pretty good, but that statistic is for "in the envelope" ejections.  That means the airspeed, altitude, attitude and vertical velocity, were within design parameters.  That means 5.6% of the time the seat failed when it shouldn't have.

Glad I didn't know that at the time.  Flying is a dangerous operation and we learn from every flight.

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