Pendulum vs Picavet FAB

A brain damaged noob writes –

what is the difference in use between a pendulum and a picavet? ie the FAB of each solution.

Thanks

Good question.

Turns out ‘FAB’ means ‘features, advantages & benefits’ so the following might be a FAB study of sorts:

P-v-P-table2

They both work equally well. I use both depending on weight- Picavet for lightest weight of rig, pendulum for ‘robust’ situations.

Pendulum: a basic form is simple to make and use but can be awkward to pack. A Pendulum needs a pivot and its length needs to match the load. A simple wire or string can act as a pendulum.

Picavet: light weight, compact. Can get expensive if you use miniature pulleys*- can tangle. A Picavet likes a bit of weight to work well- vey light rigs can stick & bounce about on a Picavet.

An active gimbal doesn’t work well suspended from a Picavet, there is feedback of motion from the suspension to the gimbal which disrupts it.
IMG_20170317_102520

With enough weight to overcome the resistance of the pulleys a Picavet works well. The longer the Picavet lines the better (up to the length of my arms anyway). Keeping the thing tidy is important, given half a chance it will tangle into a useless lump of string.

An A5 box will take a Picavet rig with a folding cross:

_MG_5601

Pendulums are easy to manage but can be bulky items. I make sure they are never longer than I can hold and keep the rig clear of the ground.

CRW_0643

Very light rigs don’t work too well with a Picavet. A pendulum does better:  this example (above) by Peter Blackmore has a flexible joint acting as a damper.

image2

After repeated pack and unpack the lines have a tendency to twist together, which doesn’t seem to stop it working.
Brooxes KAPklips are the safest and easiest method to attach the picavet to the flying line:

KAP-Klips� (set of 2)

http://www.kapshop.com/Rig-Parts-Mechanical-parts/c6_79/p168/KAP-Klips%EF%BF%BD-(set-of-2)/product_info.html

A pivot bar from plastic L section makes a good base for a pendulum suspension:

_MG_6655
I fitted brass eyelets at the pivot to reduce wear. The flexible joints are from thermoplasic brake hose and serve 2 functions: to allow folding for stowage and as a damper:
_MG_6651
A pennant cleat and carabiner secure the pivot bar to the line:
_MG_2912

I use 5 rigs for different capture methods in different conditions:

Slide29
In practice the stability required often comes from getting the rig at the right point on the line so that the lift and line tension are in balance: ‘slack line’ improves image quality regardless of the suspension method.
pendule-a-go-go
More on this here:
*these are getting hard to come by, Pekabe don’t make them anymore….
B

About billboyheritagesurvey

Heritage worker
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