5 ms·

Hm 60kg flywheel spinning at up to 36000rpm. What if it fails? I hope I won't be anywhere near the tangent

by yread 12y ago

bfwi 12y ago
What about a jet turbine? Plenty of stuff is dangerous if it "fails" in the worst way.
valarauca1 12y ago
A standard engine is a ~300lb block of iron containing 8-10 fuel air explosions per second. If so much as a piston rod gets over stressed its capable of destructively disassembling itself in a blink of an eye. A jet turbine rotate at speed in excess of 50k rpm. In the event a blade broke off, it could sale though the outer casing, your body, a cement wall, before you could hear the engine exploding. Yet... that's perfectly safe. All I'm saying is mechanical engineers are VERY good at their jobs.
- yread 12y ago
  Sure it's reasonably safe, not perfectly safe. In diesel engines, if there is a runaway and it isn't stopped the shaft can get overstressed and literally explode. Jet engines are specially armored not to let any part of the turbine escape the casing in case things go wrong (yet it still happens http://www.avherald.com/h?search_term=uncontained&opt=0&dosearch=1&search.x=0&search.y=0 http://www.avherald.com/h?search_term=uncontained&opt=0&dose... quite a lot one might say). And quite a lot of R&D was put into it not happening. Is there enough R&D being put into the flywheel not failing? EDIT: my point is that stuff that is OK in a racing car might not necessarily be safe enough to put on a bus or a tram
  - valarauca1 12y ago
    The R&D for a race car (especially an F1) is often far more advanced then that of a buss. In F1 it literally pays to have the best testing equipment, the best labs, etc. F1 prides itself on being as close to the cutting edge as their rules lets them. The famous saying, "To earn a small fortune in F1 racing, you must first spend a large one." Is very telling of this. F1 isn't done to make F1 go fast, its done to make other cars go. :.:.: A standard durability cell for engine testing for a production engine component will typically have a ~20-30 year old sensors, and 15-20 year old data acquisition system. F1 all components will likely be <5 years.
epochwolf 12y ago
Jet engines are lined with kevlar to contain engine failures. It usually works. Uncontained engine failures are extremely rare. I'd hope they are using similar technology to prevent flywheel bits from flying outside the bus. Parts around the flywheel container will probably be damaged or destroyed but the container should survive intact. There's two types of flywheels I'm aware of that are failsafe. The first is a tape flywheel. On failure it unwinds inside the container. The other type is a system where the disk is made of powdered ceramic. In the event of overload it turns to dust. A paper I found online suggests the F1 system uses a powdered ceramic disk: http://136.142.82.187/eng12/Author/data/2097.docx http://136.142.82.187/eng12/Author/data/2097.docx
NDizzle 12y ago
Well engineered scatter shields are hopefully required.

Hm 60kg flywheel spinning at up to 36000rpm. What if it fails? I hope I won't be anywhere near the tangent

by yread 12y ago

Hm 60kg flywheel spinning at up to 36000rpm. What if it fails? I hope I won't be anywhere near the tangent

bfwi 12y ago

What about a jet turbine? Plenty of stuff is dangerous if it "fails" in the worst way.

valarauca1 12y ago

A standard engine is a ~300lb block of iron containing 8-10 fuel air explosions per second. If so much as a piston rod gets over stressed its capable of destructively disassembling itself in a blink of an eye. A jet turbine rotate at speed in excess of 50k rpm. In the event a blade broke off, it could sale though the outer casing, your body, a cement wall, before you could hear the engine exploding. Yet... that's perfectly safe. All I'm saying is mechanical engineers are VERY good at their jobs.

yread 12y ago
Sure it's reasonably safe, not perfectly safe. In diesel engines, if there is a runaway and it isn't stopped the shaft can get overstressed and literally explode. Jet engines are specially armored not to let any part of the turbine escape the casing in case things go wrong (yet it still happens http://www.avherald.com/h?search_term=uncontained&opt=0&dosearch=1&search.x=0&search.y=0 http://www.avherald.com/h?search_term=uncontained&opt=0&dose... quite a lot one might say). And quite a lot of R&D was put into it not happening. Is there enough R&D being put into the flywheel not failing? EDIT: my point is that stuff that is OK in a racing car might not necessarily be safe enough to put on a bus or a tram
- valarauca1 12y ago
  The R&D for a race car (especially an F1) is often far more advanced then that of a buss. In F1 it literally pays to have the best testing equipment, the best labs, etc. F1 prides itself on being as close to the cutting edge as their rules lets them. The famous saying, "To earn a small fortune in F1 racing, you must first spend a large one." Is very telling of this. F1 isn't done to make F1 go fast, its done to make other cars go. :.:.: A standard durability cell for engine testing for a production engine component will typically have a ~20-30 year old sensors, and 15-20 year old data acquisition system. F1 all components will likely be <5 years.

epochwolf 12y ago

Jet engines are lined with kevlar to contain engine failures. It usually works. Uncontained engine failures are extremely rare. I'd hope they are using similar technology to prevent flywheel bits from flying outside the bus. Parts around the flywheel container will probably be damaged or destroyed but the container should survive intact. There's two types of flywheels I'm aware of that are failsafe. The first is a tape flywheel. On failure it unwinds inside the container. The other type is a system where the disk is made of powdered ceramic. In the event of overload it turns to dust. A paper I found online suggests the F1 system uses a powdered ceramic disk: http://136.142.82.187/eng12/Author/data/2097.docx http://136.142.82.187/eng12/Author/data/2097.docx

NDizzle 12y ago

Well engineered scatter shields are hopefully required.