Engineer respect.

"Grindintosecond" (Grindintosecond) 05/15/2018 at 17:59 • Filed to: None

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Rated for 225 mph. And can take the force of 130,000+ pounds of 737 impacting the concrete runway at a few hundred feet per second descent and regularly at 160+ knots (180mph) if need be. That is, for as many smoky instances of 0 to 1200 rpm that it can take until the rubber cap wears to the threads. Ive seen 160psi in these things. Im now a believer in that some things truly are created with Pure (F)effing Magic. Praise be to engineers.

facw > Grindintosecond 05/15/2018 at 18:13

1

When you realize maybe you need multiple wheels on your landing gear:

Much better:

Unless you want tracks ?!?

HammerheadFistpunch > facw 05/15/2018 at 18:17

3

I’ve seen that top tire, its on display near me.

a much younger me for scale.

Aremmes > Grindintosecond 05/15/2018 at 18:20

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The tires on the SR-71's landing gear were inflated to 300 psi. The wheel wells had shields to protect the fuselage against damage from bursted tires.

Ash78, voting early and often > facw 05/15/2018 at 18:21

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B-36 for the win. It’s kind of a shame that jets made it obsolete so soon.

facw > HammerheadFistpunch 05/15/2018 at 18:22

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Not quite the same I don’t think. Top one is from an XB-36, while yours (judging from the sign) is from an XB-19. Still quite large (the XB-19 was the largest bomber, and I’d assume the largest non-flying boat, built before the end of WWII)

TheTurbochargedSquirrel > Grindintosecond 05/15/2018 at 18:22

2

Tires are made with witchcraft, not science.

HammerheadFistpunch > facw 05/15/2018 at 18:25

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If I remember the XB19 tire was the largest single bogie, but I could be wrong. Probably the same tire in both uses.

For Sweden > HammerheadFistpunch 05/15/2018 at 18:41

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I hope you still have the jacket

For Sweden > TheTurbochargedSquirrel 05/15/2018 at 18:41

3

Vulcanism does sound like magic

HammerheadFistpunch > For Sweden 05/15/2018 at 18:43

1

gave it away last year when I rediscovered it in my closet and realized I couldn’t come close to fitting in it. It was tight 50 lbs ago.

For Sweden > Grindintosecond 05/15/2018 at 18:45

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Yet we still fight about tires. From an ASRS report last week, #1500814 (silly ASRS not allowing direct links)

 During preflight inspection of Aircraft X, the #2 Main Landing Gear (MLG) tire and the #3 MLG Tire were both found to have damage, affecting the airworthiness of the aircraft. The #2 MLG had an “Open Tread Splice”, as detailed in the pilot’s “Pre and Post-Flight Tire Inspection Guide (also referred to as an Open Tread Joint). The #3 MLG tire had an approximately 1"X1" V-cut in the tire tread, with a depth of approximately 3/4". When looking into the cut with a flashlight, the top ply cord could be seen. I notified the Captain of my findings, and we went to inspect the tires together. We both agreed that the “Open Tread Splice” on the #2 tire fit the description and details of the “Pre and Post-Flight Tire Inspection Guide. We also concurred, that it was the tire ply cord that could be witnessed at the bottom of the cut on the #3 tire. Maintenance Control was notified, and Maintenance came out to the aircraft several minutes later. While sitting in the cockpit, an AMT entered the cockpit to review the logbook, wanting to know who wrote the tires up. When the Captain told him that he did, he told the Captain that both tires were “good”. The Captain shared our mutual-agreement on the condition of the tires, and the AMT refused to relent. All three of us visited the tires, and our opinions were again exchanged. However, when the AMT said he was going to sign both of the tires off, I told him that if he did, I would refuse to fly the aircraft. The AMT called for two other Maintenance techs to gather their opinions, and initially both of them surmised that each tire was good. Again, for a third time, the Captain and I shared our position on the tires. The Maintenance supervisor agreed that he would replace both tires, since the Captain and I felt that the aircraft was unsafe. However, I told him that our concern alone, should not be the reason for changing the tires. If he could produce the applicable section but in the [Maintenance Manual] that says that the conditions were acceptable, then I would be OK with taking the aircraft. However, from past experience, I knew that both of these conditions affect the airworthiness of the tires. After much discussion, the Maintenance supervisor reviewed the [Maintenance Manual], and found the location where an “Open Joint” in a tread cannot exceed 3mm length, nor 1mm depth (both of which were far-exceeded). For the #3 tire, he also located a section that restricts the aircraft to three additional landings, when the top ply cord becomes visible. Both tires were replaced, and the flight left with a lengthy delay.

arl > For Sweden 05/15/2018 at 19:01

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Reasons like this are why I never, ever, want to fly.

Full of the sound of the Gran Fury, signifying nothing. > Grindintosecond 05/15/2018 at 19:03

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Good for land speed record trucks as well. After all, what’s the market for actual truck tires designed for 200+ MPH? Zero, so you have to find something suitable somewhere.

Full of the sound of the Gran Fury, signifying nothing. > For Sweden 05/15/2018 at 19:10

5

I remember an incident at LAX a few years back with one of my least favorite customers, Air India. The contract mechanic warned them to change a tire before departure, but no, they wanted to take care of it back home. Not surprisingly, it blew on takeoff, and the underside of the aircraft, mostly fairings and flight control surfaces, were punctured. Circle around and dump several thousands of gallons of Jet A into Santa Monica Bay and then spend seven figures in repairs and taking a 747 out of service for a month or so. Cheapskates.

f86sabre > Grindintosecond 05/15/2018 at 19:50

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Fun fact: a 737 is much harder on tires than almost any plane in the commercial fleet. They have gotten heavier, but the wheel well does not have room for more tire. By rights, they probably should have a four wheel boogie on each main gear.

TorqueToYield > Grindintosecond 05/15/2018 at 20:37

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Throw enough money and time at a problem and you can get what you want with 99.999% reliability. Aerospace in a nutshell.

Also, why you should think about life statistically and not deterministically.

bob and john > Full of the sound of the Gran Fury, signifying nothing. 05/15/2018 at 21:05

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holy fuck nuggets thats an expensive :”nah bro, i’ll do it at home”

Full of the sound of the Gran Fury, signifying nothing. > bob and john 05/15/2018 at 21:10

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I can’t remember if it was more or less expensive as the tailstand that was driven into the leading edge of a 747 wing just as the aircraft was about to push back. That one nearly killed the driver; if he wasn’t 300+ lbs the center of the steering wheel probably would have punctured his chest.

Liam Farrell > f86sabre 05/15/2018 at 21:38

1

That is really interesting to think about, makes total sense coming from a small domestic aircraft to the transoceanic jet we have today. Never something I really thought about.

oldmxer > HammerheadFistpunch 05/15/2018 at 23:58

1

u are correct sir

You can tell a Finn but you can't tell him much > f86sabre 05/16/2018 at 09:33

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It blows my mind that as thoroughly as the 737 has been evolved they basically haven’t touched the landing gear on it. The MTOW has just about doubled, the passenger capacity has almost doubled, the plane is 40+ feet longer than it started, the engines fans have increased their diameter by 40%, it’s got new wings, yet it’s still got the same landing gear. The landing gear have to be about the only system on the 737 that hasn’t been completely redesigned since it was introduced.

f86sabre > You can tell a Finn but you can't tell him much 05/16/2018 at 14:35

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The year have evolved and are beefier, but there just isn’t space in the wheel well for any more tire and wheel. That also limits brake size.