SR-71 Blackbird

[F22RaptorDude]

Direct your attention to these
C-17
http://youtu.be/c5FjTcctkC4

B-29 with X1
http://youtu.be/5x291HbsyDI

Even bigger B-29
http://youtu.be/KmKdA6L_MWk

I've seen all of them before, the SR-71 took me by surprise. The B-29 with the X1 is amazing though! It takes 3 people to fly, 2 to fly the B-29 and 1 for the X1

[Strip]

The fuel is so hard to ignite that tri-ethyl borane is injected into the combustion section
to light it. Tri-ethyl borane is a highly toxic liquid that spontaneously ignites with air and
carries a distinctive green flame.

Link to the SR-71 flight manual...

www.sr-71.org/blackbird/manual/

[F22RaptorDude]

The fuel is so hard to ignite that tri-ethyl borane is injected into the combustion section
to light it. Tri-ethyl borane is a highly toxic liquid that spontaneously ignites with air and
carries a distinctive green flame.

Link to the SR-71 flight manual...

www.sr-71.org/blackbird/manual/

So does a large supply of it have to be taken?

[Strip]

No, once the fuel is ignited the combustion is self sustaining.

The most important characteristic of JP-7 is the low vapor pressure, it was designed
that way to prevent boil off at high altitude. A secondary design characteristic is the
very high ignition temperature so the fuel can be used as a coolant.

[F22RaptorDude]

No, once the fuel is ignited the combustion is self sustaining.

The most important characteristic of JP-7 is the low vapor pressure, it was designed
that way to prevent boil off at high altitude. A secondary design characteristic is the
very high ignition temperature.

I was just thinking about that, after the engines start the combustion chamber will be extremely hot, so I figured the fuel would just ignite from the super high temperatures. It all makes sense now, there's so much to know about all this. I'm very eager to learn.

[Strip]

The SR-71 suffers from a condition known as an unstart, the engine ingests supersonic
air and the compressor stall.  The abrupt asymmetrical thrust has been known to yaw
the aircraft so hard that helmets were cracked. The onboard computer automatically
adjusts the inlet spike to reestablish subsonic airflow and combustion is restored, usually.
At times this process has occured without the crew even noticing the problem, only once
the maintence crew checked the logs did they become aware.

Rather interesting phenomenon, its covered pretty well in the flight manual...

[F22RaptorDude]

The SR-71 suffers from a condition known as an unstart, the engine ingests supersonic
air and the compressor stall.  The abrupt asymmetrical thrust has been known to yaw
the aircraft so hard that helmets were cracked. The onboard computer automatically
adjusts the inlet spike to reestablish subsonic airflow and combustion is restored, usually.
At times this process has occured without the crew even noticing the problem, only once
the maintence crew checked the logs did they become aware.

Rather interesting phenomenon, its covered pretty well in the flight manual...

I recall hearing about this on Great Planes. The ducts moved forward and aft to adjust the air flow to prevent supersonic air from entering and stalling the compressors. Its what I recall off the bat. I also saw this technology on Wings of the Luftwaffe about the ME-262, used in the exhaust, the bullets could be retracted or extended to allow for more thrust speeds or something along the lines of that. This must have been reverse engineered to go over the intake aside from the exhaust duct. Am I right at all or am I speaking Gibberish?

[Strip]

Although the Me-262 did have a rear bullet it bears little in relationship to the inlet spike
of the SR-71. The bullet was designed to produce a variable exit area which maintained
the proper exit velocity.

Here is some good engineering material on the Junker Jumo 004 used by the Me-262....

http://www.enginehistory.org/German/Me-262/Me262_Engine_2.pdf

The SR-71 inlet spike is designed to steer a shockwave into a specially shaped area of
the inlet section. The shockwave is reflected and slowed so that the air becomes subsonic
and able to be compressed. An unstart occurred when the center body shock wave was
ingested into the throat inlet.

[F22RaptorDude]

Although the Me-262 did have a rear bullet it bears little in relationship to the inlet spike
of the SR-71. The bullet was designed to produce a variable exit area which maintained
the proper exit velocity.

Here is some good engineering material on the Junker Jumo 004 used by the Me-262....

http://www.enginehistory.org/German/Me-262/Me262_Engine_2.pdf

The SR-71 inlet spike is designed to steer a shockwave into a specially shaped area of
the inlet section. The shockwave is reflected and slowed so that the air becomes subsonic
and able to be compressed. An unstart occurred when the center body shock wave was
ingested into the throat inlet.

(Image removed from quote.)

If steers the shockwave, I mean thats alot of energy I would assume right? I mean do the intake spikes get battered often? I mean I understand how it works in general to reflect the waves/shocks but to me it would seem the spike takes a good beating? Sorry If I might not catch on, I'm eager to learn but its hard to take in alot.

[Strip]

Depends on how you look at it, the air is so thin that the main concern is aerodynamic
heating, the brunt of a the shockwave is only felt at the very tip of the spike. You will
notice a shine silver tip on the inlet spike, I believe that is Rene 41 but I could mistaken.

Regardless of the name it was a very high temp durable metal, the remainder of the spike
was titanium.

[clerick]

I'm no expert on the stuff, but IIRC, it has similar properties to diesel fuel.

Most jet fuel does, as well as Keorsene.  I used to fuel aircraft at the local international airport and we ran jet-a in our diesel trucks.  Occasionally a mechanic would trundle over and dump some ATF into the tank for lubrication.