Throwing coins in plane engines ?

[J4CKO]

Saw another post about people from certain areas of the globe thinking tis a good idea to throw loose change into a High Bypass Turbofan engine before take off, for good luck. How spectacularly stupid do you have to be to do that ?

Now I know its not a great idea, its a particularly daft one, especially when you are trying to get some luck out of the deal.

But realistically, aside from the airline being duty bound to go rooting round in the engine cowls and the cash retrieved probably not covering the incurred expenses from the delay, what is the actual risk to a modern Turbofan ?

I expect that they can deal with certain sized pieces of debris when spinning full tilt as part of the design and I am guessing here, that a normal collection of loose change would be expelled as the blade span up, in that they generate enough air movement at low engine speed to move a few grammes of coins out before the blades have enough speed/momentum to cause any/much damage ? Was also thinking that one getting trapped between blade and inlet that could be bad but interested to hear the opinion of those who know a lot more than me.

If there are any elderly Chinese ladies (main offender group with this MO) reading this looking for validation of this practice, just don't, asking from an engineering standpoint, its still a stupid idea !


I have a mangled blade off a CFM56, that was used to attempt liquidizing a large Sea bird, now that did damage it, but a 20p piece ?

[J4CKO]

Mave said:

Even a single 20p piece is capable of doing a lot of damage to a jet engine, especially if it gets into the core. Even if the aerofoils don't immediately disintegrate, the damage can make them much more susceptible to subsequent fatigue :-(

Capable, but how likely is it ?

[J4CKO]

Mave said:

J4CKO said:

Mave said:

Even a single 20p piece is capable of doing a lot of damage to a jet engine, especially if it gets into the core. Even if the aerofoils don't immediately disintegrate, the damage can make them much more susceptible to subsequent fatigue :-(

Capable, but how likely is it ?

Pretty likely. You hit one piece of metal with another one doing a few hundred mph and there will be damage. I've seen individual bolts (small ones!) taking chunks out of all stages through the compressor, and leaving indentations deep enough to be able yo confirm the thread pitch!

Yeah, if its running, but coins can only be launched by folk lacking in gorm at zero rpm, then you get the fairly slow process of spinning them up to full operating speed and I cant see a coin hanging round long whilst any volume of air starts to move through so an altogether gentler exit than depositing a coin in at 10,000 rpm plus.

[J4CKO]

I suspect its one of those things where people who aren't used to something aren't entirely sure how to behave, I dont think an older Chinese lady, perhaps from outside a city is perhaps going to be a regular on PPrune and isnt that well up on Turbofans but does have some older superstitions about chucking money in stuff.

We tend to be around fairly well travelled folk so it comes as a shock when some dont know how to act, I was on an Air India flight once and someone had crimped a length on the floor, now I am guessing that wasnt a well travelled Businessman from Delhi, but someone who is used to parking their breakfast wherever they see fit.

Did some filming for the Hyundai I30N thing last year and a bus with a few Chinese tourists appeared, one bloke just wandered into the shot shouting at his party, oblivious to the car, the cameras, the lighting etc, he also gobbed loudly and lavishly, we were aghast but he just didnt seem to know and can only really be that he wasnt used to it and didnt twig he should keep back and keep quiet.

So, bit of education required and also, keep them away from where they can launch loose change into engines.

[J4CKO]

Brads67 said:

Educate superstitious chinese ?

Not a chance.

Confucius say, those who throw coins in jet engines get a large fine and prevented from flying might do it ?