hi-speed ejections

In article ,
(Bill McClain) writes:
snippage

Hi all,

My Joshua was saying, "See, I told you people can eject from
Blackbirds!" Hey, who knew?

Am I right about that Foxbat? It was going Mach 3+ because of runaway
engines? What happened to aircraft and pilot? I'd imagine the
engines would flame out and the pilot would punch out; I'd hate to
think that the Foxbat would just blow up or something.

I wouldn't say that it was runaway engines, myself. Pretty much all
turbojet/turbofan engines are limited by the strength of teh materiels
of the rotating components (Compressors & Turbines). Remember that
these parts are highly loaded, and are spinning very fast, so there's
a lot of stress & strain on the blade roots and the disks that hold
the blades. The most common limit is the temperature of teh hot gas
entering the turbine section. That's pretty constant, though. 1500
Degrees K is 1500 Degress K no matter what altitude you're at, or how
fast you're going. The compreressor section, up front, is another
matter - As the engine's air is rammed into teh inlets and slowed
down, it's pressure and temperature increase. (This is, generally, a
good thing - the more air, at a higher pressure, the more thrust. As
teh air is compressed by each stage of the compressor, it heats up
more. At some point, it's possible to exceed teh tmperature limits of
the materiels in the compressor. Generally, the effects of an
overtemp in the compressor section aren't catastrophic, unless you're
above the limits for a long time. It will dramatically shorten the
useful life of those components, so an engine swap would be necessary
after landing to ensuer that the next flight's going to be safe.
It appears that that's what happened with the Foxbat over Egypt. The
pilot, for Tactical Reasons (Like getting his Recce Data back)
exceeded the placarded Mach 2.8 limit on the aircraft. He successfuly
landed the airplane in Egypt, and the engines got swapped.


Lowest and slowest ejections are kind of interesting, too. I bet the
Navy probably holds some interesting records there, mostly at sea.
)

There have been some successful underwater ejections. Those are a lot
more dangerous than they may sound. Water's heavy, thick stuff.
--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

A little bit of a pingpong...


Peter Stickney wrote in message ...
In article ,
(Bill McClain) writes:
snippage

Hi all,

My Joshua was saying, "See, I told you people can eject from
Blackbirds!" Hey, who knew?

Because its "ram-air" speed is quite low, around 350 KIAS due to the high
altitude & thin air. The major concern is oxygen supply-it is a looong way
down! The heat is irrelevant because the Blackbird heats due to
"heat-soaking".


Am I right about that Foxbat? It was going Mach 3+ because of runaway
engines? What happened to aircraft and pilot? I'd imagine the
engines would flame out and the pilot would punch out; I'd hate to
think that the Foxbat would just blow up or something.

NO runaway engines. Foxbat is THE first airplane with FADEC control RRD-15B
designed by Chekunov OKB. It is the aerodynamic movemens that have to be
monitored. At placarded speed of M 2.83 and 5.5g sustained turn at 30 tonnes
weight (MiG-25PD-P has 5 g limit), wingtips fold upward for 70cm each (due
to heavy wings-it has reservoirs INSIDE the wings, not "integrals"), even
with differential stabilators rolls are "bending" the wings!


I wouldn't say that it was runaway engines, myself. Pretty much all
turbojet/turbofan engines are limited by the strength of teh materiels
of the rotating components (Compressors & Turbines).

Correct. That's why Foxbat A engine turbines are covered with 30 micron
silver (0,03-0,05mm smoothnes) by electrolysis-5 kg per engine! Foxbat E
(MiG-25PD) uses silver/radium that gives 0,01 smoothnes on ?-15BD-300.

Remember that
these parts are highly loaded, and are spinning very fast, so there's
a lot of stress & strain on the blade roots and the disks that hold
the blades. The most common limit is the temperature of teh hot gas
entering the turbine section.

Correct for turbofans, wrong for the MiG low-pressure turbojets. The limit
for them is RAM-air pressure (i.e. compressor fans). Let me give You the
temperatures at max dynamic thrust; Engine inlet temperature 320C;
compressor max temp-700 Centigrade. Fuel-adding section temperature-300C
(fuel cooling!); Air-evaporation section with alcohol-87C. So, turbine gets
rather cool air/fuel/alcohol mixture. TET-1,000C. All at M2,8 at 11,000
meters (or 13,000 meters at Middle east). Estimated max speed flight time-40
minutes (it was only 8 minutes on first machines!)

Oh, heat soaking. Having built-in reservoirs rather than integrals like
SR-71 (that leak when airplane is "cold"!), evaporated air is bled from
AE-section at -20C to wings and fuselage compartments. For example, the
mighty 600-KW "Smerch" radar working temperature is 50-60C due to good
cooling, so there is no need for nitrogen-cooling. Same goes for wings and
fuselage, they are "air-blown".

That's pretty constant, though. 1500
Degrees K is 1500 Degress K no matter what altitude you're at, or how
fast you're going. The compreressor section, up front, is another
matter - As the engine's air is rammed into teh inlets and slowed
down, it's pressure and temperature increase. (This is, generally, a
good thing - the more air, at a higher pressure, the more thrust. As
teh air is compressed by each stage of the compressor, it heats up
more. At some point, it's possible to exceed teh tmperature limits of
the materiels in the compressor. Generally, the effects of an
overtemp in the compressor section aren't catastrophic, unless you're
above the limits for a long time. It will dramatically shorten the
useful life of those components, so an engine swap would be necessary
after landing to ensuer that the next flight's going to be safe.
It appears that that's what happened with the Foxbat over Egypt. The
pilot, for Tactical Reasons (Like getting his Recce Data back)
exceeded the placarded Mach 2.8 limit on the aircraft. He successfuly
landed the airplane in Egypt, and the engines got swapped.


Wrongo about Egypt. Pilot Bezevec (that's his name) went (dashed) to M3.2
due to Hawk SAM launch detection via RWR. No damage to the aircraft or
engines. The R-15B-300 engines on Bezevec's aircraft were installed after
General Kadomcev got killed in engine bay fire in April 1969 when engines
got placarded at lower temps. He was a test pilot and simple firewalled the
engines. Let me remind You that slightly-modified (I mean re-engined E-155)
MiG-25M can go M3.2 until it runs out of fuel.

However, the rest is fine. CIT and TIT limits MiG-25 to go over 1,200 Kmph
indicated airspeed at ANY altitude. That's why MiG-25 cannot break sound
barrier (without bpilot being reprimanded! 8-) at the sea level-compressor
becomes "overcompressed" at that level at 1,200 IAS/TAS and there is simply
too little air for afterburner to go over stage 1 safely without making
engine turbine running hot (afterburner has 3 stages/levels).

However, it has automatic stabilator-adjustment when firing R-40s to avoid
roll/yaw/pitch change (another first on the fighter). Stabilators are cut
like wings and stabilators on F-15 as a good anti-flutter measure (F-15
"stole" this feature from MiG-25, F-15 prototype had anti-flutter weights!),
efficient airbrake (also coupled with stabilator to avoid pitch change). A
low-level flying prototype of MiG-25P made a snap-up attack ripple-fire with
all four R-40(Radar and IR) and evaporated MiG-15 drone.



Lowest and slowest ejections are kind of interesting, too. I bet the
Navy probably holds some interesting records there, mostly at sea.
)

Not uncommon. Kadomcev killed himself since the darn aircraft continued to
fly. It was an outboard engine-bay fire so the plane probably just
disintegrated when exploded. When the darn thing, being that MiG-25, SR-71,
XB-70 or whatever starts to move, even clipped wings/stabilizers/engines
cannot make it stop to fly straight&level... the early (pre-production)
MiG-25s had smaller on early machines, and produced same interference like
on F-14 (hence the bigger "fishtails" on early 25-s) and even wigtips that
were good only for straight and level flight.

There have been some successful underwater ejections. Those are a lot
more dangerous than they may sound. Water's heavy, thick stuff.

Depending of the height, it is all the same if one drops at sea, lake or
concrete.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster-

Quite.

--

Nele

NULLA ROSA SINE SPINA

From "The truth about MiG-25"
Kryla Rodiny, 1990

quote
"There was one ocassion at Gorkii, when pilot had to eject at Mach 2.67. He
resumed flight status one year later. Earlier, one pilot sucessfully ejected
at a takeoff on the ground"
end quote

Be aware that MiG-25 measured airspeed of M 2.83/5.5g is at 11-12,000
metres, while SR-71 achieves the same speed at much higher altitude. Please
do the math what is the "ram-air" speed (around 550 KIAS).
Also, the ejection seat of the MiG-25 is KM1M, NOT K-36 (however, it got
installed in MiG-25PD series from 1978 onwards, but these case happened in
"P" model).


--

Nele

NULLA ROSA SINE SPINA
Bill McClain wrote in message ...
snippage

Hi all,

My Joshua was saying, "See, I told you people can eject from
Blackbirds!" Hey, who knew?

Am I right about that Foxbat? It was going Mach 3+ because of runaway
engines? What happened to aircraft and pilot? I'd imagine the
engines would flame out and the pilot would punch out; I'd hate to
think that the Foxbat would just blow up or something.

Lowest and slowest ejections are kind of interesting, too. I bet the
Navy probably holds some interesting records there, mostly at sea.
)

mah wrote:

Hi Bill & son

It can be done.

Aircraft such as the B-58 used a seat that had a clamshell capsule that
enclosed the occupant. The soviet (now Russian) K-36 seat uses booms in
front to make a calm area.

The K-36 seat has telescoping booms that extend REARWARDS - to stabilise the
seat - in much the same way as the small drogue chute on western designs.

It has a projection that extends upwards between the pilots knees and a
device behind his knees that rises so that his legs are nearer his torso.

Think of the wake on a boat. There is a
relatively calm area behind.

Having the occupant survive without injury is another story. Others
responders have already discussed this.

Shameless plug - visit my web site at
http://showcase.netins.net/web/herke...ion/eject.html

Great to see a young person asking quesitons.

MAH




--
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++
Ken Duffey - Flanker Freak & Russian Aviation Enthusiast
Flankers Website - http://www.flankers.co.uk/
Genuine E-mailers - Replace sukhoi with flanker
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++

The K-36 seat has telescoping booms that extend REARWARDS - to stabilise the
seat - in much the same way as the small drogue chute on western designs.

I though it also had a wind blast deflector the popped up *in front* of the
seat?


BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

BUFDRVR wrote:

The K-36 seat has telescoping booms that extend REARWARDS - to stabilise the
seat - in much the same way as the small drogue chute on western designs.

I though it also had a wind blast deflector the popped up *in front* of the
seat?

BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

It does - a sort of telescoping arm between the pilots knees, with what looks like
a small mesh screen.

But looking at photos, it only seems to extend to groin/stomach height.

I'll see if I can find a photo.

I also read recently that the Martin-Baker seat on the Rafale had a device whereby
the pilot does not need to attach his ankles to the seat - it is all done
automatically.

This was supposed to be a wonder development - but the K-36 seat has had it for
years!

It has a webbing strap that goes from the outer side of the seat, next to the
right side of one ankle - then up and over the footwell and attaches to a pulley
on the seat on the left side of the ankle - same arrangement for the other ankle.

So the pilot sits down and puts his feet on the rudder pedals in the footwell - he
doesn't have to attach any ankle straps.

As soon as the seat fires, these webbing straps retract, pulling his ankles onto
the seat. There are also risers behind his knees to raise them towards his
stomach, the aforementioned windbreak, the stabilising arms etc.

All in all a very effective design - as demonstrated by the K-36 Ejection Seat
Display Teams at RAF Fairford (two) and Le Bourget (three)

++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++
Ken Duffey - Flanker Freak & Russian Aviation Enthusiast
Flankers Website - http://www.flankers.co.uk/
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++

Ken Duffey wrote in message ...
BUFDRVR wrote:

The K-36 seat has telescoping booms that extend REARWARDS - to stabilise the
seat - in much the same way as the small drogue chute on western designs.

I though it also had a wind blast deflector the popped up *in front* of the
seat?

BUFDRVR

"Stay on the bomb run boys, I'm gonna get those bomb doors open if it harelips
everyone on Bear Creek"

It does - a sort of telescoping arm between the pilots knees, with what looks like
a small mesh screen.

But looking at photos, it only seems to extend to groin/stomach height.

I'll see if I can find a photo.

I also read recently that the Martin-Baker seat on the Rafale had a device whereby
the pilot does not need to attach his ankles to the seat - it is all done
automatically.

This was supposed to be a wonder development - but the K-36 seat has had it
for years!

The version of the K36 was also to be found on the XB70 Valkurie. I
recall reading (in Wings i think) that the only survivor of a XB70
F104 mid air crash got his hand caught in the seats clamshells; when
he finally got his arm out and ejected the shell didn't close and he
recalls seeing the XB70 and F104 debris tumbling away from him through
the gap in the clamshells.

On 30 Jan 2004 23:31:29 GMT, (BUFDRVR) wrote:

The K-36 seat has telescoping booms that extend REARWARDS - to stabilise the
seat - in much the same way as the small drogue chute on western designs.

I though it also had a wind blast deflector the popped up *in front* of the
seat?

I'm sure you're right. I saw a "Discovery Wings" programme recently
that showed the mechanics of the Russian ejection system. Wind
deflector at front, and rear booms on seat for stabilisation. I'm not
sure how this compare with the latest Martin-Baker zero-zero seats.

--
Kulvinder Singh Matharu
Contact details : http://www.metalvortex.com/form/form.htm
Website : http://www.metalvortex.com/

"It ain't Coca Cola, it's rice" - The Clash

Shameless plug - visit my web site at
http://showcase.netins.net/web/herke...ion/eject.html

Um?

http://showcase.netins.net/web/herke...n/history.html

Um, this completely ignores the German development of ejection seats.
Germans had first successful ejection, first ejection seats in series
production aircraft and did some 60 successful ejections during the WW2.

jok

"Jukka O. Kauppinen" wrote in message ...
Shameless plug - visit my web site at
http://showcase.netins.net/web/herke...ion/eject.html

Um?

http://showcase.netins.net/web/herke...n/history.html

Um, this completely ignores the German development of ejection seats.
Germans had first successful ejection, first ejection seats in series
production aircraft and did some 60 successful ejections during the WW2.

jok

Ejection seats were standard for test aircraft but also many
production aircraft.

The development of these seats came out of a Luftwaffe study that
showed that over 50% of attempted parachute egresses from stricken
aircraft failed.

(Hitting a tail fin cost many an aviator his life)

Heinkel retained responsibility for all ejection seat developments.
As the company was in the east of Germany in an area that would of
come under Soviet controll and I think was annexed into Poland and I
expect some of the work was lost though post war the USAF's ejection
seats were styled after German ideas.

Aircraft that had compressed air ejection seats include:

Heinkel He 219 Uhu nightfighter. (The cabin was ahead of the props
and unless the engines were shut down and feathered the egressing crew
migh have been mangelled)

Dornier Do 335 Pfiel. (The aircraft had a pusher propellor).
Interestingly the ejection sequence involved seperation of the prop
blades and vertical fin by explosive bolts for extra safey in certain
situations.

I believe some crew members of the Heinkel He 177 Grief bomber also
had standard ejection seats.

These were all compressed air ejection seats. Compressed air must
have given smooth acceleration but the seats apparently weigh and
maintenance issues. (How much I don't know)

The Heinkel He 162 used pyrotechics. (The engine was mounted dorsalay
on the aircraft) and was much lighter. It probably used several
charges sequenced in time.


I've often thought that if a light weight ejection seat had of been
fitted to the German fighers eg Me 109G and FW190A onward some of the
Luftwaffes pilot shortage problems could have been solved.