Luge run!
“I used to bullseye womp-rats in my T-16 back home, they aren’t much bigger than two femtometers.”
—Very Tiny Luke
21 Likes
Worry about cracked intake fan blades, busted hydraulic hoses, birds on takeoff/landing or drunk pilots. The wing rivets, not so much.
So. You know that teeny tiny barely perceptible rust spot you see on your stainless steel spoon?
THAT’S WHAT IT LOOKS LIKE!
2 Likes
Looks like a Grand Canyon to me.
1 Like
Petite Canyon.
3 Likes
Oui, mon ami petite canyon.
Now waiting for ES to reveal the Petite Tetons.
2 Likes
Been there.
There ain’t nothing petite about the Tetons, mon ami.
Ah, but somewhere out there in nature, there must be a sub-miniature version, an analogy, ready to be revealed through an electron microscope. Hence… La Petite Tetons. Out there. Some where.
Well find it, mon ami, for I don’t have access to that technology, but I suspect you do…
I am only a spectator, Monsieur I, and, as such, must depend on the finders of tiny cracks and tiny mountain ranges.
2 Likes
No, what I meant is that if someone had bodged one repair, who knows what other horrors there might be?
1 Like
But what if anyone would pour some mercury on the corroding spot…?
1 Like
To continue the pedantry, if you look at piece of aluminum, you see a coating of oxidation, but it’s extremely thin and transparent. It protects the metal from further oxidation, and doesn’t expand like iron oxides do, and so doesn’t form scales that break off and allow further rusting.
3 Likes
Indeed. I briefly worked with an A&P mechanic out of JFK or O’Hare (don’t recall which) who could do a fast stroll around an aircraft and reel off exactly what was wrong and needed checking versus stuff that wasn’t a priority. I also worked with a USAF-trained jet mechanic who “helped” me by putting two quarts of hydraulic fluid into my #3 engine oil reservoir…
…believe that was the same kid who was boning his supervisor’s wife (with the consent of both wife and supervisor) and who later threatened me and five or six other dumbasses in the dorm with a pistol, having been egged into it by said dumbasses. Also used a government credit card to purchase and install quite the sound system in his personal vehicle. The USAF then kindly “helped” him out of the USAF.
Gonna guess that’d be frowned upon.
1 Like
I think of it as a way of talking about wavelengths. In the case of using electrons, it’s often more or less one wavelength, so the proper “color” palette would be monochrome, typically black and white on the video being taken. However, if you have multiple wavelengths of electrons you’re trying to visualize, it makes sense to apply our visual spectrum to the relative wavelengths.
Color is a construct but it can be a useful one.
2 Likes
That’s a very neat little experiment and goes some way to explaining why corrosion engineering is so difficult. Anything which relies on an adherent oxide layer for corrosion protection - including the stainless steels - is frequently only a little stress, a dilute acid, mercury, a lichen or a chelating agent away from some kind of catastrophic failure. One problem I had to trouble shoot involved someone who changed the specification on a solder flux to a supposedly more stable and easier to clean one that, unfortunately, included a chelating agent. The slightest trace of damp, and all of a sudden wires were corroding at the joint.
Your tiny crack in steel, someone else’s metallurgical nightmare.
1 Like
I mentioned fan blades earlier, if only because I see them almost as works of art. Spun at many thousands of revolutions per minute, jiggled and rattled in their casings by all manner of things including the aircraft itself, resisting high and low temperatures, and yet nothing more than thin slips of metal alloy. Part of the standard postflight inspection is to check the blades (especially the leading edges) for bends, bumps or cracks, and it’s not uncommon to find them every now and again (middle, middle right blades bent and scratched/potentially cracked):
Damage above would likely trigger a full inspection of the engine and definitely a grounding of the a/c, but smaller nicks would be filed smooth and documented. I don’t know the split between “HFS GROUND IT” and “nbd” but I’m glad I never experienced a failure of those blades.
See pages 47-48 for engineering porn concerning the fan blade itself and how it attaches to the fan disk outer rim on the F108-CFM56 engine.
Edit: Speaking of tiny cracks, metal fatigue can be bad stuff:
3 Likes
I knew there was a reason why I needed to wash all my cutlery again.
You monster.
(No. Wait. Wrong file.)
1 Like
