Aeronautical Insanity: switching to secondary tolerances

The Something Awful Forums > Discussion > Automotive Insanity > Aeronautical Insanity: switching to secondary tolerances

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MrYenko: Jun 18, 2012; #2 isn't ALWAYS bad...

Nebakenezzer posted:

Big plane-nerd question: why did the Tu-22 Blinder have downward firing ejection seats?

My gut instinct is that it was so crew could be strapped in by ground crew without needing a platform. Why replace a simple steel ladder and platform with a complex system that severely degraded seat performance? To demonstrate the superiority of Marxism, obviously

The B-52 has 2 downward firing seats, B-47s had a single downward firing seat depending on modification, and the F-104 originally had a downward firing seat. This is by no means a conclusive list, there are quite a few examples. There are lots of different reasons they could have chosen that system, not least of which is that zero-zero seats didn't begin to be a thing until the early-mid sixties, and weren't commonplace until quite a bit later. If you already have to plan on having a no-escape zone, the direction of ejection starts to matter quite a bit less. For a supersonic aircraft with top-mounted engines like the Tu-22, down-firing seats very well may have been quite a bit safer or an easier engineering job (or both) than upward firing seats, particularly during a supersonic ejection, which was generally considered to be the bigger threat than evacuation of the aircraft on the ground.

I can't find solid dates, but I think the first zero-zero system in service wasn't even an ejection seat in the traditional sense, but the Yankee Escape system which was installed on Navy Skyraiders.

Interestingly, Robert Stanley was the test pilot for the first flight of the XP-59 Airacomet, and went on with Bell as vice president of engineering for the X-1 project. His company not only designed the Yankee system, but the escape capsules for the B-58. Mr. Stanley was killed (along with both of his sons) in the crash of the company Aero Commander while returning from the Bahamas, a few miles off the coast of Fort Lauderdale in 1977.

# ? Mar 29, 2020 14:58

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# ? Jun 9, 2024 08:12

mlmp08: Jul 11, 2004; Prepare for my priapic projectile's exalted penetration; Nap Ghost

Wingnut Ninja posted:

Not being familiar with War Thunder, are people exceeding max airspeed limitations which results in airframe damage (such as losing flaps and other control surfaces), or are people dogfighting with flaps extended? You normally only use flaps for low-speed maneuvers like takeoff and landing. I can't think of a reason why you'd want them for combat. Speed brakes on a dive bomber, maybe, but that's different (and designed for higher airspeeds).

In game players will be inverted 1 kph from their max mach number and then open palm slam the flaps and landing gear buttons to create drag and try to pull sick Gs. Imagine a pretty forgiving flight model, flown by a bunch of people who make Jerry Wagner look like a good aviator who are also motivated by the fact that people are shooting at them or they need to ripple off bombs on tanks. They might have fixed it, but you used to be able to have a friend shoot the fixed gear off your Stuka to fly faster.

On some aircraft they flaps will extend mega-slow at high speeds and so you have audio/visual warnings to knock it off and retract them. Others have hydraulic assists that will happily slam your flaps open and then leave them to tear off into the ether.

# ? Mar 29, 2020 15:13

aphid_licker: Jan 7, 2009

Doesn't blasting you downwards basically make your head (+helmet) pull really hard on your neck?

# ? Mar 29, 2020 15:15

mlmp08: Jul 11, 2004; Prepare for my priapic projectile's exalted penetration; Nap Ghost

aphid_licker posted:

Doesn't blasting you downwards basically make your head (+helmet) pull really hard on your neck?

https://www.criticalpast.com/video/65675032452_parachutist_F-89-and-B-47-in-flight_man-ejected-from-plane_parachutist-descending

I can't tell if this video is slowed down or not, but regardless, the downward B-47 ejection seat appears to leave far less violently than vertical ejection seats do. More a plop than a rocket sled ride.

# ? Mar 29, 2020 15:18

Xenoborg: Mar 10, 2007

The B-52 downward ejection seat�s post ejection hole in the aircraft is also used to evacuate crew members 7-10 who are not in an ejection seat as well as injured people who would be at more risk in one.

That�s only relevant for high altitude bailing though. The downward ejection seats say they should work at 500 ft, but you want have bailing time for anyone else.

# ? Mar 29, 2020 15:19

Platystemon: Feb 13, 2012; BREADS

The Yankee escape system seems like a great way to gently caress up your back.

# ? Mar 29, 2020 15:22

Bob A Feet: Aug 10, 2005; Dear diary, I got another erection today at work. SO embarrassing, but kinda hot. The CO asked me to fix up his dress uniform. I had stayed late at work to move his badges 1/8" to the left and pointed it out this morning. 1SG spanked me while the CO watched, once they caught it. Tomorrow I get to start all over again...

aphid_licker posted:

Doesn't blasting you downwards basically make your head (+helmet) pull really hard on your neck?

Blasting upwards does too. That lightweight helmet becomes pretty heavy when it�s hit with an impulse of 30Gs. If you are out of the proper body position you�re pretty much guaranteed some form of injury. One of the Marines that perished during the C-130/F-18 collision in late 2018 was alive when he hit the water but was pretty severely injured from incorrect ejection procedures; the NFO pulled the ejection handle before the pilot had a chance to remove his NVGs and get in the proper brace.

# ? Mar 29, 2020 15:31

Xakura: Jan 10, 2019; A safety-conscious little mouse!

vessbot posted:

Lots of American planes had it too, like early F-104's, bottom seats of the B-52, and some others too.

Haha, holy poo poo, not only did it try to kill you when landing, it offered no escape while doing so. That's just cruel.

# ? Mar 29, 2020 15:34

aphid_licker: Jan 7, 2009

Make final approach inverted for safety reasons

# ? Mar 29, 2020 15:57

Godholio: Aug 28, 2002; Does a bear split in the woods near Zheleznogorsk?

Platystemon posted:

The Yankee escape system seems like a great way to gently caress up your back.

That's true for ejection in general.

# ? Mar 29, 2020 17:21

BIG HEADLINE: Jun 13, 2006; "Stand back, Ottawan ruffian, or face my lumens!"

Platystemon posted:

The Yankee escape system seems like a great way to gently caress up your back.

Significantly less so than dying in a crash, I'd imagine.

# ? Mar 29, 2020 17:29

karoshi: Nov 4, 2008; "Can somebody mspaint eyes on the steaming packages? TIA" yeah well fuck you too buddy, this is the best you're gonna get. Is this even "work-safe"? Let's find out!

A350 snake stowage area, nifty! https://www.youtube.com/watch?v=LxS2RR-Vx_s

# ? Mar 29, 2020 17:34

Molentik: Apr 30, 2013

~Coxy posted:

Do you happen to know whether KLM freight is still operating 747 or is this literally the last last?

This was the last passenger flight, Martinair (owned by KLM) still has three 747 cargo's flying.

# ? Mar 30, 2020 10:16

Deptfordx: Dec 23, 2013

aphid_licker posted:

Make final approach inverted for safety reasons

Actually what does happen if you eject completely inverted? I'm talking about a modern conventional fired upwards (i.e. from the planes topside) ejection and of course assuming you're at a safe altitude. Can the chute deploy correctly and right you?

# ? Mar 30, 2020 11:40

Platystemon: Feb 13, 2012; BREADS

Deptfordx posted:

Actually what does happen if you eject completely inverted? I'm talking about a modern conventional fired upwards (i.e. from the planes topside) ejection and of course assuming you're at a safe altitude. Can the chute deploy correctly and right you?

quote:

hawkeye, As per the ACES II literature, the ACES II can recover a pilot from a 180 degree roll at 150ft (assuming a 150kts, level ejection.) Since the speed changes things slightly, it should not be assumed that an ejection at a higher or lower speed would be successful at that altitude, and any sink rate would complicate matters too.

As to seats that 'allow ejection in an inverted position', all do to a degree. The issue is how fast the chute develops, which depends on the system design. There have only been two tested seats that have steerability to drive themselves upright and away from the ground, which is what I think you meant. The First was the Vertical Seeking Seat (VSS) from the US Navy driven Maximum Performance Ejection Seat program. The VSS was tested by firing it out of an inverted cockpit suspended from a crane. The seat detected the ground based on RF emissions and a large spherical rocket motor on the bottom could control the seat enough to right it and drive it away from the ground. This was not usable in a service seat because the electronics, articulation equipment, and rocket took up all the space normally used for survival equipment.

The other seat tested was the 4th Generation Ejection seat as a follow-on/part of the CRew Escape Technologies (CREST) program. The 4th Gen seat was a highly modified F-16 ACES II. They kept the chassis, parachute assembly with mortar, and seat separation systems. Virtually all else on the seat was changed. The sequencer was lobotomized to only fire the parachute mortar, the bucket assembly received new sidewalls and leg protection, the CKU-5/A/A rocket catapult was converted to catapult only. There were more changes, but the most significant was the addition of a large H-shaped rocket motor that consisted of five segments of rocket, and four nozzles. The nozzles were pintle systems that allowed for controlled thrust. There was an additional rocket controller which was connected to an underseat inertial navigation system. The 4th Gen seat was only tested on a sled track. The four nozzles on the rocket were canted downwards and inwards. On firing the seat would right itself in the roll axis and then tilt in pitch to the appropriate pitch for best trajectory. Just prior to rocket burn-out (approx. 1 second) the seat would pitch to a feet first, relative to the seat motion, trajectory. Then at seat separation the parachute would be mortared off in the cleanest direction for smooth deployment.

The 4th Gen tests were fantastic (even the failures) but the expense and size of the rockets made it infeasable for adoption in current aircraft. The pintle technology (by Aerojet) is being examined for possible use in future seats, but again the expense is a sticking point.

Kevin
The Ejection Site

http://www.f-16.net/forum/viewtopic.php?t=166

# ? Mar 30, 2020 12:03

aphid_licker: Jan 7, 2009

150 feet

# ? Mar 30, 2020 12:38

mlmp08: Jul 11, 2004; Prepare for my priapic projectile's exalted penetration; Nap Ghost

Speaking of assisted recovery/survival, this quote from one of the Auto-GCAS incidents:

�My memory is that I started the fight and then I could see my instructor and the next thing I remember is just waking up,� the pilot recalled. �It feels weird because I think I�m waking up from my bed. In my helmet, I can hear him screaming �recover, recover� at me and when I open my eyes I just see my legs and the whole cockpit. It doesn�t really make sense.

�I got up over the horizon pretty fast again. It�s all thanks to the Auto-GCAS system, which got me out of the roll and started the recovery for me.�

# ? Mar 30, 2020 14:54

ThisIsJohnWayne: Feb 23, 2007; Ooo! Look at me! NO DON'T LOOK AT ME!

Didn't SAAB develop a domestic Swedish variant of GCAS for the Viggen in the 80's? I think that was part of the early development of GCAS in the US

# ? Mar 30, 2020 15:05

Mr. Funny Pants: Apr 9, 2001

Godholio posted:

That's true for ejection in general.

That big carrier documentary that Martin Sheen narrated, can't remember the name, but they did a segment on an ejection that happened while they were filming. One pilot said that after a previous ejection, he lost two inches in height because it compressed his spine.

# ? Mar 30, 2020 15:07

shame on an IGA: Apr 8, 2005

mlmp08 posted:

Speaking of assisted recovery/survival, this quote from one of the Auto-GCAS incidents:

“My memory is that I started the fight and then I could see my instructor and the next thing I remember is just waking up,” the pilot recalled. “It feels weird because I think I’m waking up from my bed. In my helmet, I can hear him screaming ‘recover, recover’ at me and when I open my eyes I just see my legs and the whole cockpit. It doesn’t really make sense.

“I got up over the horizon pretty fast again. It’s all thanks to the Auto-GCAS system, which got me out of the roll and started the recovery for me.”

https://www.youtube.com/watch?v=WkZGL7RQBVw

# ? Mar 30, 2020 15:44

bull3964: Nov 18, 2000; DO YOU HEAR THAT? THAT'S THE SOUND OF ME PATTING MYSELF ON THE BACK.

Pittsburgh airport had to close a runway to store planes.

https://www.post-gazette.com/busine...es/202003300136

# ? Mar 31, 2020 16:37

InAndOutBrennan: Dec 11, 2008

The Real Amethyst posted:

Seeing as earlier we had submarines talk I thought this would be interesting to share from the bullshit forum OSHA thread.

Nope nope nope nope.

# ? Mar 31, 2020 16:51

Serjeant Buzfuz: Dec 5, 2009

shame on an IGA posted:

https://www.youtube.com/watch?v=WkZGL7RQBVw

youtube comment posted:

3 years later, Boeing implemented the MCAS, the exact opposit system : the pilot is perfectly conscious, but the plane is crashing anyway.

# ? Mar 31, 2020 16:55

Nebakenezzer: Sep 13, 2005; The Mote in God's Eye

Comstar posted:

5 Free Osprey books

https://ospreypublishing.com/blog/Free_eBooks_week_2/

Aeronautically related: the early marks of Hurricane

# ? Mar 31, 2020 17:26

Nebakenezzer: Sep 13, 2005; The Mote in God's Eye

Basically an ad but still cool: https://www.youtube.com/watch?v=e76RTcB6Rew

# ? Apr 2, 2020 00:09

Humphreys: Jan 26, 2013; We conceived a way to use my mother as a porn mule

Russia. Rockets. Tanks.

https://www.youtube.com/watch?v=Wv0qg7zrjl4

# ? Apr 2, 2020 11:00

Nebakenezzer: Sep 13, 2005; The Mote in God's Eye

Russia. Medical supplies. To NYC?

https://www.youtube.com/watch?v=6GPhZbwMCEc

# ? Apr 2, 2020 16:13

sincx: Jul 13, 2012; furiously masturbating to anime titties

sincx fucked around with this message at 05:49 on Mar 23, 2021

# ? Apr 2, 2020 19:47

Munin: Nov 14, 2004

sincx posted:

https://twitter.com/mountain_ghosts/status/1245754158910705668?s=19

Didn't that get caught a while back?

# ? Apr 2, 2020 19:56

hobbesmaster: Jan 28, 2008

Yeah I thought 787s had to be �turned off� after every flight just to be sure due to a variety of issues like that.

# ? Apr 2, 2020 19:59

joat mon: Oct 15, 2009; I am the master of my lamp;
I am the captain of my tub.

Munin posted:

Didn't that get caught a while back?

No, it's a different 787 software error

joat mon fucked around with this message at 20:02 on Apr 2, 2020

# ? Apr 2, 2020 19:59

Munin: Nov 14, 2004

joat mon posted:

No, it's a different 787 software error

lol @ Boeing

# ? Apr 2, 2020 20:05

Murgos: Oct 21, 2010

You typically flow a requirement for a period of continuous operation which is interpreted as register overflow protection.

I mean, registers are only so big so counters have to stop some place.

51 days of continuous operation doesn't sound like someone screwed up for something that doesn't have a mission critical requirement to operate 24/7 but I don't know what the requirement actually is.

# ? Apr 2, 2020 20:06

Midjack: Dec 24, 2007

Munin posted:

lol @ Boeing

# ? Apr 2, 2020 20:24

wolrah: May 8, 2006; what?

Murgos posted:

You typically flow a requirement for a period of continuous operation which is interpreted as register overflow protection.

I mean, registers are only so big so counters have to stop some place.

51 days of continuous operation doesn't sound like someone screwed up for something that doesn't have a mission critical requirement to operate 24/7 but I don't know what the requirement actually is.

You are 100% correct, but at this point anyone involved in these kinds of systems should be expected to be aware of the limits they're imposing when choosing counter sizes. Windows 9x's uptime limits and the 2038 problem in Unix-style timestamps are both widely discussed parts of computing lore (and the latter is still being worked on).

If they know they're putting a limit in, they should either gracefully handle exceeding it and test this case, or at the very least document that system X must be rebooted every Y days. The fact that this is coming out now means that not only did they not do this originally, but they didn't go back through and look for these kinds of things even after the last one.

# ? Apr 2, 2020 21:26

priznat: Jul 7, 2009; Let's get drunk and kiss each other all night.

Came up in my youtube recs, it knows how much I love watching Twin Otters make insanely short landings:

https://www.youtube.com/watch?v=JBxpxK3MO5w

Man the first twin otter looks like it is just hanging there on approach, takes forever just to cross that roadway :haw:

Can practically take the taxiway off within 50 feet of wheels touching down

# ? Apr 3, 2020 04:10

Murgos: Oct 21, 2010

wolrah posted:

You are 100% correct, but at this point anyone involved in these kinds of systems should be expected to be aware of the limits they're imposing when choosing counter sizes.

I agree that this should be, 'as designed' and documented but without going into the actual problem report, it very well may be at the level of that subsystem's requirements and/or design description. If there is already an end user document that puts a limit on continuous operation you wouldn't specify a second, longer interval reboot requirement, it would just confuse people.

I suppose my real point is that this article seems alarmist for the purpose of cheap clicks, and possibly industrial sabotage, not that there is any real problem.

# ? Apr 3, 2020 13:00

Vando: Oct 26, 2007; stoats about

I mean, when you get to the stage of issuing ADs I don't think it's safe to say it's "not any real problem" if you ask me

# ? Apr 3, 2020 13:55

Murgos: Oct 21, 2010

Fair enough.

# ? Apr 3, 2020 14:19

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# ? Jun 9, 2024 08:12

wolrah: May 8, 2006; what?

Murgos posted:

If there is already an end user document that puts a limit on continuous operation you wouldn't specify a second, longer interval reboot requirement, it would just confuse people.

There isn't though, the previous "you need to reboot your plane this often" thing with the generators was something like 8 months where this is less than two.

quote:

I suppose my real point is that this article seems alarmist for the purpose of cheap clicks, and possibly industrial sabotage, not that there is any real problem.

As noted, it is very much a real problem. It's not a problem that would cause the plane to fall out of the sky by any means, but as I understand it any plane that had been running longer than the counter could handle had silently lost the ability to detect a number of sensor failures.

Basically it's the sort of thing that would get discussed about 2/3 of the way through the episode of Air Crash Investigations.

# ? Apr 3, 2020 15:42

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