Video cassette - topology question

[N_Cook]

If a tape gets scrunched up and loops once around the pivot, inside the
spool, jammed between the hank of tape and the "top" spool flange. Taking
the cover of the cassette off and removing one spool. Keeping both spools
horizontal, you unwind the scrunched loop by pulling out. Then would you
expect to have to flip one spool , one turn, to bring tape laying back to
normal? Would that removal of a twist in the tape mean the scrunched tape
has looped over the top of the spool flange before scrunching or stayed
within the plane of the normal tape passage, ie the volume of space of
width of the tape.

 

[William Sommerwerck]

I'm not sure I actually understand your question. However...

Most (if not all) VCR tapes, regardless of format, are "B wind" -- the oxide
faces "out".

Most analog audio reel-to-reel formats are "A wind" -- the oxide faces "in".
Most analog audio cartridge and cassette formats are "B wind".

It doesn't matter "who struck John". You want the tape to go in straight
line from one hub to the other, with oxide facing the "outside" of the
cartridge.

Mr Cook, your writing is often unclear. You sometimes write as if English
were not your native language. You need to learn to write more clearly.

 

[Phil Allison]

"William Sommerwerck"

Mr Cook, your writing is often unclear. You sometimes write as if English
were not your native language. You need to learn to write more clearly.

** Not possible to write better than he thinks.

Need a brain transplant to fix that.



..... Phil

 

[William Sommerwerck]

Mr Cook, your writing is often unclear. You sometimes write

As I understood him, he asked if videocassette tape was meant
to have a half- (or greater) twist. Or, by extension, should it lay
untwisted like an audiotape, whether open reel or cassette.

Thanks.

The answer, of course, is untwisted.

 

[Meat Plow]

If a tape gets scrunched up and loops once around the pivot, inside the
spool, jammed between the hank of tape and the "top" spool flange.
Taking the cover of the cassette off and removing one spool. Keeping
both spools horizontal, you unwind the scrunched loop by pulling out.
Then would you expect to have to flip one spool , one turn, to bring
tape laying back to normal? Would that removal of a twist in the tape
mean the scrunched tape has looped over the top of the spool flange
before scrunching or stayed within the plane of the normal tape passage,
ie the volume of space of width of the tape.

Could you please translate that into common English?

 

[Meat Plow]

Thanks.

The answer, of course, is untwisted.

Oh that's what he said. Well crap, it's simply logic that tells you tapes
should not be twisted.

 

[N_Cook]

Could you please translate that into common English?

How do you explain a Klein bottle in text ?
It is a topological question involving twists and turns. If when a tape
runs at full tilt back and the other end hits the clear tape end stop,
failing of rate sensor. In that jarring of the tape, if it loops over the
spool and between the spool flange and the clear cover of the cassette,
before tightening up and jamming between the reel of tape and the spool
flange, will it lead to a twist in the tape .

 

[William Sommerwerck]

How do you explain a Klein bottle in text?

Only "continuous loop" tape cartridges use a closed loop of tape. The
infamous 8-track cartridge pulled the tape from the inside of the spool,
then fed it back to the outside. The tape has to be slightly twisted to fit
within a compact shell, but there is no net turning of the tape -- the top
edge of the tape remains on the top at all times.

I know of no tape system that used a Moebius strip.

 

[N_Cook]

How do you explain a Klein bottle in text ?
It is a topological question involving twists and turns. If when a tape
runs at full tilt back and the other end hits the clear tape end stop,
failing of rate sensor. In that jarring of the tape, if it loops over the
spool and between the spool flange and the clear cover of the cassette,
before tightening up and jamming between the reel of tape and the spool
flange, will it lead to a twist in the tape .

Yes.
Just played about with an audio reel recorder, to check the scenario
you describe.
and if the tape loops over the reel, you must then loop it back again
(the way it came, as it were) - if you continue to pull tape off the
spool there is a twist.
HTH
B.

&&&&&

That was what I was trying to get an opinion on. I was aware that pulling
wire axially off the end disc of a cable drum introduced a twist in the wire
but could not decide , thinking about it for a cassette . Whether the same
applied to slipping one turn off a VCR spool by it passing over the top of
the spool in the gap between spool and transparent window on the cassette
cover, then slipping back into the volume where the tape should be, but
mangled and pulled in.

 

[Meat Plow]

How do you explain a Klein bottle in text ?
It is a topological question involving twists and turns. If when a tape
runs at full tilt back and the other end hits the clear tape end stop,
failing of rate sensor. In that jarring of the tape, if it loops over
the spool and between the spool flange and the clear cover of the
cassette, before tightening up and jamming between the reel of tape and
the spool flange, will it lead to a twist in the tape .

Ok that makes more sense. What failure mode are you trying to explain?

 

[Cydrome Leader]

I'm not sure I actually understand your question. However...

Most (if not all) VCR tapes, regardless of format, are "B wind" -- the oxide
faces "out".

Most analog audio reel-to-reel formats are "A wind" -- the oxide faces "in".
Most analog audio cartridge and cassette formats are "B wind".

I never knew there was a name for this oxide in or out. I recall some
horrible hong kong or taiwanese audio cassettes that were wound the wrong
way- the oxide was on the wrong side.