Detail W14

Detail W14

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Science & Technology

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• DSCF6625

[BenVanDeWaal]

I am sorry, but that's the way it is (maybe Q = 1000 is more realistic for a Lego pendulum). The amplitude should be measured in degrees, not chords.

Buy a textbook, like My Own Right Time by Philip Woodward.

NB: undampened means Q is infinite and the isochronism is perfect.

[BenVanDeWaal]

Q = 4.53 times the number of periods the pendulum makes in decaying to half amplitude. Q=10,000 is a good value for a pendulum in air.

[BenVanDeWaal]

I didn't have these parts at that time, but the next time I will surely give it a try.

[BenVanDeWaal]

No, it is not. The pendulum rotates about the point where the knife rests in the edge, as shown in the closeup Detail W14. The pendulum is impulsed at its lower end, which is rare in conventional pendulum clocks. The advantage is that a very small force is required to drive the pendulum, because of the long arm. The disadvantage, of course, is that you need 2 supports, one near the ceiling for the pendulum bearing, one near the ground for the escapemechanism and the gear train.

[merijnvanwouden]

what is the point in connecting the "slinger"(sorry for you english people, I don't know the english word, in mean that thing which goed to the right and to the left) to the axis on a lower point?

[BenVanDeWaal]

I do not understand the question. Do you mean the pendulum ('slinger'), or do you mean the bob (gewicht onder aan de slinger)?

[KEvronista]

.... sheesh. q factor is worse than first gauged, not better.

one of these days, i just might know what the hell i'm talking about....

D'Oh

[KEvronista]

"d'oh!" should be my middle name. no, KEvron, half the chord does not equate to half the amplitude. on the upside, this means my q factor is slightly better than i had first guaged.

i eventually figure out this stuff, it just takes me a while. a couple of months, sometimes....

KEvron

[KEvronista]

.... q factor somewhere between 1100-1200. not too shabby for lego bricks.

KEvron

[KEvronista]

@KEvronista

sorry, "i've switched from 60477 slopes to 41769 and 41770...."

i type faster than i think, and i hunt and peck.

KEvron

[KEvronista]

.... i've switched from 6232 bricks to 41769 and 41770 wedge plates, turned on their sides and SNOTed onto technic bricks. they offer both reduced surface space and profile, and they form a more obtuse angle than would the bricks or slopes. i've worked it into my arnie. again, no proper q factor measurement, but i was able to adjust the g.a. pawl to allow for even greater amplitude. i'm may be wrong, but i take this as an indication of increased q factor.

KEvron

[KEvronista]

@KEvronista

er, "1/2 chord should result in 1/2 amplitude...."

buy a book. i know, but even used copies of mort are fetching a healthy sum. besides, i've got you! ;)

KEvron, pest

[KEvronista]

@BenVanDeWaal

"degrees, not chords"

yes, i know, but we're talking about measuring decay. the chord the only possible practical measurement (i suppose one could measure the y elevation, but the chord seems a simpler approach); degree of amplitude and arc L are derived from that measurement. as they're proportional, 1/2 chord should equal 1/2 amplitude.

since you mentioned it: i do use the chord to get a rough estimate of the amplitude. at 1 to 1 1/2 degrees, they're close.

KEvron

[KEvronista]

@KEvronista

d'oh! "....while the amplitude is in degradation...."

KEvron, novice

[KEvronista]

....here's doozy for you: does a free-swinging (non-impulsed, undampened) pendulum still exhibit the effects of isochronism while the period is in degradation? if i understand the theory correctly, this is the case for a theoretical pendulum, but what of a practical? for the q factor, i figured i'd just time the half-degradation and divide by 2 (i use a seconds pendulum), and that would give me the oscillation count, but now i'm not so sure.

KEvron