12ft.lb ... or ... 12 fpe ?

[Gareth W-B]

Morning all. Since a similar thread on here many many moons ago (which I simply can not now find) which pre-dated my BBS Mod life iirc (so that makes it at least pre 2008), from which I learned twelve feet per pound should be written 12ft.lb, I have always written it that way.

Of late, however, both on here and another forum I visit, I've started to notice people writing twelve feet per pound as 12 fpe, so is this also a correct notation, is it the new accepted notation that dinosaurs like me should now adopt and replace the former with, or is the former still the one and only correct notation, or, err, should I get a grip as it doesn't really matter?

[LESS THAN FORTUITOUS KENNETH]

fpe is ft lb energy int it? Eggzackerly same as 12 ft/lb.

[cooper_dan]

get a grip

[tinbum]

I've started using fpe a lot of the time as it's easier to type.

[lensman57]

They are both correct and ' wrong ' at the same time as the they are not SI units. To be strictly correct the muzzle energy of a gun should really be expressed in joules, one J being when a force of one newton acts over one meter of distance in the direction of motion of the object/projectile.

A.G

[Rapidnick]

Morning all. Since a similar thread on here many many moons ago (which I simply can not now find) which pre-dated my BBS Mod life iirc (so that makes it at least pre 2008), from which I learned twelve feet per pound should be written 12ft.lb, I have always written it that way.

Of late, however, both on here and another forum I visit, I've started to notice people writing twelve feet per pound as 12 fpe, so is this also a correct notation, is it the new accepted notation that dinosaurs like me should now adopt and replace the former with, or is the former still the one and only correct notation, or, err, should I get a grip as it doesn't really matter?

Gareth it really doesn't matter! I suspect that many on here don't know what a 'foot pound' is -let alone 12 of them! Also I suspect that even fewer understand the relationship between velocity and projectile weight.

[VALE BOY]

I think it may be due to the prevalence of tautology that pervades everyday speech nowadays...people overstating the same thing, twice or more, perhaps for emphasis. Such as, 'reverse back into that space'..."Tables can be pre-booked in advance". In fact this "pre-booking" expression really bugs me, as the correct terminology is simply 'Booking'!
The top one of the lot is probably the typical Politician's statement which commences..."Currently at this present moment in time"!

[Rich]

12 ft/lb is wrong, always.

[snock]

I've heard of 12psi, 12 lb of pressure and 12lb - it's amazing that so many air gunners don't know, or don't understand, the limits placed upon them.

[Murphy]

I always write 12ftlb.

But does it really matter if its understood.

[deejayuu]

Pedantic but to answer the OP. Imperial measurements for "work done" give Force (lbs.) moved through Distance (ft.) to give a multiple ie
Force X Distance so algebraic convention ft.lb.
"Feet per pound" is a division so ft./lb will give a much smaller, incorrect for our purpose, result using the same values.
I assume fpe to be abbreviation of "ft.lbs of energy" but probably wrong.

[deejayuu]

I always write 12ftlb.

But does it really matter if its understood.

No M'Lud/Your Honour/mate!!

[Murphy]

To be honest you could write any number under 12 and word on a UK forum and people would understand.

My rifle is shooting 11.7 bananas.

My rifle is putting out 11.7 daffodils.

My power went up to 11.7 puppys.

With these new pellets it went up to 11.7 Llanfairpwllgwyngyllgogerychwyrndrobwllllantysilio gogogoch.

[Gareth W-B]

.
Thanks chaps (err I think ), will stay as I am then, quoting 12ft.lb if it is just a minor question of semantics -- although am sorely tempted to follow Murphy's lead, and start referring to twelve bananas per penguin lol.

[lensman57]

12 ft/lb is wrong, always.

Yes it should be ft.lbs to express energy. One foot of distance divided by one pound of weight is rather meaningless.

A.G