Ejector Seat Article

[KPax]

What is the opinion on the newspaper article in todays newspaper that the MOD refused to udgrade the seats in the Canberra on cost. Surely there is more to this than just cost.

[BEagle]

The decision was probably made long before the present huggy-fluffy 'duty of care' era at a time when the ancient old beast was considered to be on its way to retirement. But the usual vacillation about replacing the PR9 or its high value capability has led to it staying in service far longer than was ever intended.

My personal view? The PR9 fleet should get a zero-zero capability as an urgent operational requirement; asymmetric training in the T4 should cease until it too has been modified. Regardless of cost.

How many other RAF a/c with ejector seats do not have a zero-zero capability?

[santiago15]

"How many other RAF a/c with ejector seats do not have a zero-zero capability?"

Just the Tucano?

[jimgriff]

I stand to be corrected, but the Tucano is fitted with Martin Baker Mk 10L ejection seats which do have a zero / zero capability.

[Jackonicko]

Which newspaper was that, then?

[BigGrecian]

Haven "ridden" a Tucano ejector seat I can assure you that its not a Zero Zero seat.
Think it was a Martin-Baker 8LC? :8

[jimgriff]

The Mk 8 series of seat was only ever flown on the TSR2.

[Right Stuff]

You are both correct -

The TSR 2 did indeed have a MK8 seat but this line was scrapped along with the aircraft, the lessons learnt went into the MK 10 and the number 8 was free so...

it is a MK 8LC in the Tucano. Basically a MK 10 but without the rocket motor. It has a 0/60 envelope (i.e. need 60kts at ground level)

[jimgriff]

I hold my hand up to incorrect info I posted earlier. You are correct as to the mark of seat fitted to the Tucano and I was wrong.....
I now have to go and update my website as I have the tucano fitted with a 10L oops!!

Sorry Chaps / chappesses:O

[BigGrecian]

It has a 0/60 envelope (i.e. need 60kts at ground level)
RightStuff, as part of the checks we call 70 kts as that was the limit for safe ejection. I assume therefore that they added a 10kt safe guard to make sure we really were inside the limits?:confused:

[Right Stuff]

Yes, that would be why. Although you will survive from a 60kt ejection it would not be a comfortable landing; these are not 'safety factored' speeds - an ejection at 55kts would be very bad news indeed.

70kts gives you a sensible margin to allow for airspeed decay etc.

[jimgriff]

There are a few reasons for the min speed requirement:

1. To get enough "wind" to make the drogues effective.

2. To ensure the trajectory baseline is long enough to ensure all the "bells and whistles" have time to operate and ensure canopy deployment.

The envelope would be degraded if one was not staight and level at the time of ejection.

I remember that the Mk 4 seat on the lightning was OK from 90kts at ground level but the book suggested that 250kts woukld be the best speed (if there is such a thing) for premeditated ejection.

Does anyone know if you go through the canopy on the Tucano (MDC?)

[BigGrecian]

There is MDC in the Canopy of the Tucano, as well as an emergency canopy fracture handle, for ground egress.
The drill was:
Mask on
Visor Down
Eyes Tightly Shut
Pull handle firmly.

[Runaway Gun]

So if you already flew your Tucano with your mask (and helmet) on, visor down, eyes shut and was experienced at pulling, I guess it would be a very fast ejection indeed?

[Right Stuff]

The reason speed is a good thing to have comes down to parachute (and to a lesser extent, drogue) inflation. With forward speed, the 'chute will fill horizontally as you travel forwards thereby requiring very little vertical extent to sprout fully - so, less height is required to get the pilot beneath a stable chute.

Excess speed doesn't help either as the drag on the seat can monkey with your trajectory quite noticeably. The time taken for the 'bells and whistles' to operate isn't the real issue here - that chute will only fill (zero-zero case) after you start descending rapidly. Rocket seats give you that height.

[5 Forward 6 Back]

The Tucano only had traditional MDC for the rear cockpit; it'd shatter, but the canopy was too thick at the front. It's a one piece bit strengthened for inadvertent visits from our feathered friends.

The front cockpit had "linear cutting cord" if I remember groundschool right, which was meant to burn the canopy material down to something like 1/32" thick. The idea was that the airflow over the canopy would then whip the "doors" open. If they didn't, then the little prongs on the seat would push them apart for you.

Hence why you always had to sit with a fist sized gap between you and the canopy...

[victor two]

As a slight variation to the thread and regarding checklists prior to ejection. A US marine corps FA/18 pilot safely ejected in the Northern Territory of Australia this last Tuesday. The cause has not yet been disclosed or determined. He was returning from a live bombing run at the local range ( all bombs already gone) and ejected at about 3000 feet and 8 miles south of the Tindal AFB. Prior to ejection, he did elect to fire his full load of cannon shells into vacant bushland near the base.

Is that a typical checklist item should you have time?

cheers
Vic

[jimgriff]

Probably saved some erk having to find some 2,000 live cannon shells spread over a thousand acres of Austrailia.
Nice thoughtful gesture by the pilot!!;)

[Photoplanet]

As far as I'm aware, linear cutting cord and MDC (miniature detonating cord) are the same thing, a small explosive designed to fragment the perspex into pieces small enough to allow the seat to pass through without too much injury or damage.

Regarding the fist gap between head and canopy, I can only speak from experience of the Tornado F3, and technically speaking, the MDC is a backup to the canopy jettison rockets, the MDC firing after the seat has risen a short distance without the canopy jettison operating. Comfort may also play a part, as in a negative G manoeuvre, the helmet would get closer to the canopy, and the constant fist gap is a margin of comfort, as well as maintaining a constant eyeline for the pilot.