"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....
.... 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.
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.
....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.
ah. i've seen the equation, but didn't fully understand it. so i just measure the initial chord length, count the number of periods until the chord length is half the initial, and times 4.53. got it.
10,000?! yikes! if my math is right, that's more than an hour for a seconds pendulum. my best effort has probably been a tenth of that or less. how'd your w14 perform?
i just threw one together. for the egdes, i used two 6232 bricks (wish i had a couple 90258's). using two 4263 plates, fixed to the end of a 15L beam, and two type 2 half bushes, i could rotate the axle to allow the 6232 bricks a 45 degree orientation, thereby providing my knife edges. i haven't tried it in an escapement yet, but i let it run free for a while and it seems to run quite smoothly.
um.... what's a practical method for measuring q factor?
ben, have you tried using slope bricks (say, 60477 or 4286), placed side-by-side and facing opposite directions, as a cradle for the knife edges? i know they have rough surfaces, but that may not necesarrily have an effect on the motion. it may well even reduce the friction by reducing surface contact.
how does it work does it have a weight the pendulum is at the top? email me plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz my email is claydog42@gmail,com
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.
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?
Yes i mean the pendulum. To me it looks just like you've only connected it to the axis at a lower point. Is this true? Then, what is the point in doing this?
It depends on what you want. Long-term precision or short term? Long-term is very difficult, because then the performance of the gear-train comes into play and keeping the drop of the weight within reasonable limits. Short-time is easily achieved, e.g. 1 in 1000 seconds. I did not measure it, but I think W1 and W8 can be taken to high short-time precision.
W14 may be good for the long time, but I have to improve the gear train to reduce the weight drop and improve reliability.
This is a clever way to build a pivot for a pendulum! Have you done any tests to see how much longer a pendulum will swing with this method compared to the usual axle-through-a-hole method?
I may try implementing this idea on my clock to see if it will run better...
I placed this video for somebody who wants to build the W14 with it's very long pendulum. It has also the virtue of being invulnerable to forces perpendicular to the swing plane. I plan to measure it's Q-value and compare it with other supports.
.... 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 9 months ago
"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 9 months ago
.... q factor somewhere between 1100-1200. not too shabby for lego bricks.
KEvron
KEvronista 11 months ago
.... 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 11 months ago
@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 11 months ago
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 11 months ago
@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 11 months ago
@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 11 months ago
....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
KEvronista 11 months ago
@KEvronista
d'oh! "....while the amplitude is in degradation...."
KEvron, novice
KEvronista 11 months ago
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 11 months ago
@BenVanDeWaal
ah. i've seen the equation, but didn't fully understand it. so i just measure the initial chord length, count the number of periods until the chord length is half the initial, and times 4.53. got it.
10,000?! yikes! if my math is right, that's more than an hour for a seconds pendulum. my best effort has probably been a tenth of that or less. how'd your w14 perform?
KEvron
KEvronista 11 months ago
I didn't have these parts at that time, but the next time I will surely give it a try.
BenVanDeWaal 11 months ago
@BenVanDeWaal
i just threw one together. for the egdes, i used two 6232 bricks (wish i had a couple 90258's). using two 4263 plates, fixed to the end of a 15L beam, and two type 2 half bushes, i could rotate the axle to allow the 6232 bricks a 45 degree orientation, thereby providing my knife edges. i haven't tried it in an escapement yet, but i let it run free for a while and it seems to run quite smoothly.
um.... what's a practical method for measuring q factor?
KEvron
KEvronista 11 months ago
ben, have you tried using slope bricks (say, 60477 or 4286), placed side-by-side and facing opposite directions, as a cradle for the knife edges? i know they have rough surfaces, but that may not necesarrily have an effect on the motion. it may well even reduce the friction by reducing surface contact.
KEvron
KEvronista 11 months ago
This has been flagged as spam show
how does it work does it have a weight the pendulum is at the top? email me plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz my email is claydog42@gmail,com
Claydog42 1 year ago
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.
BenVanDeWaal 2 years ago
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?
merijnvanwouden 2 years ago
I do not understand the question. Do you mean the pendulum ('slinger'), or do you mean the bob (gewicht onder aan de slinger)?
BenVanDeWaal 2 years ago
Yes i mean the pendulum. To me it looks just like you've only connected it to the axis at a lower point. Is this true? Then, what is the point in doing this?
merijnvanwouden 2 years ago
Wich is the most precise of all this assemblies?
Great job, love each one of them :)
c0pi 3 years ago
It depends on what you want. Long-term precision or short term? Long-term is very difficult, because then the performance of the gear-train comes into play and keeping the drop of the weight within reasonable limits. Short-time is easily achieved, e.g. 1 in 1000 seconds. I did not measure it, but I think W1 and W8 can be taken to high short-time precision.
W14 may be good for the long time, but I have to improve the gear train to reduce the weight drop and improve reliability.
BenVanDeWaal 3 years ago
This is a clever way to build a pivot for a pendulum! Have you done any tests to see how much longer a pendulum will swing with this method compared to the usual axle-through-a-hole method?
I may try implementing this idea on my clock to see if it will run better...
sforbs 3 years ago
I placed this video for somebody who wants to build the W14 with it's very long pendulum. It has also the virtue of being invulnerable to forces perpendicular to the swing plane. I plan to measure it's Q-value and compare it with other supports.
BenVanDeWaal 3 years ago