physics buffs. why 7200rpm?
#1
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physics buffs. why 7200rpm?
hard drives are most common at 7200rpm
so are many engines that are limited to around 7000rpm?
is that on purpose because of some physical limitations or just "because they other guys did it" seems like a good idea
so are many engines that are limited to around 7000rpm?
is that on purpose because of some physical limitations or just "because they other guys did it" seems like a good idea
#2
Sanji
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Re: physics buffs. why 7200rpm?
The comment on hard drives is inaccurate. There's plenty of 5k, 9k, 10k, and 15k hard drives out there. Then, there's the fact that most diesel engines operate under 3,500 RPM's, and older engines couldn't push much past lower RPM's as well. Harmonics are an issue and so is bearing load, but the comparison you're making isn't comparing apples to apples. If that were the case, then all electric motors and combustion engines would hover around the 7k mark redline. You're making a rather large leap, that's really not there.
#3
Honda-Tech Member
Re: physics buffs. why 7200rpm?
not so much a matter of the limit of physics as it is a byproduct of similar design constraints / intended uses.
sport bikes tend to be higher 10-14k rpm. they have different constraints and intended uses.
lawnmower/small engines (4 stroke) tend to be lower 4-5k rpm. again, different constraints and uses.
some input parameters that dictate the theoretical limit are mean piston speed (factors: durability requirements, stroke/torque curve, cost to build and operate), valve spring stiffness (factors: cost, desired torque peak, fuel economy), total cross-sectional area of intake and/or exhaust path.
sport bikes tend to be higher 10-14k rpm. they have different constraints and intended uses.
lawnmower/small engines (4 stroke) tend to be lower 4-5k rpm. again, different constraints and uses.
some input parameters that dictate the theoretical limit are mean piston speed (factors: durability requirements, stroke/torque curve, cost to build and operate), valve spring stiffness (factors: cost, desired torque peak, fuel economy), total cross-sectional area of intake and/or exhaust path.
#5
Honda-Tech Member
#6
Honda-Tech Member
Re: physics buffs. why 7200rpm?
between a hard drive and an engine the only similarity is that they both spin.
hard drives are BLDC motors I believe. like automotive gasoline engines they are also subject to design constraints such as cost, performance, size, ect. but the similarities end there.
hard drives are BLDC motors I believe. like automotive gasoline engines they are also subject to design constraints such as cost, performance, size, ect. but the similarities end there.
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