I would like to welcome Dave Stroble and his son Matt to the dz, Matt is one of our full time AFF and Tandem Instructors this year and Matt will be editing, packing, and other things around the dz.

Sahra our new manifester will be here on the 1st of March.

Greetings, All!

1.      Continuity plans & engineering

Since the early days of competitive formation skydiving, a crucial part of planning a successful skydive has been the engineering stage.  Sometimes building a formation a different way may be slightly more efficient than building it the way you built it last time.  Over the course of many jumps, a team's scores will be noticeably higher if they keep to a small set (one to three) of builds for each formation.  The speed and reliability achieved through familiarity easily exceed the gains achieved by finding a new build which involves a little less turning, or a little less translation, in a particular situation.

Every team therefore develops its continuity plan, which includes:

·        A set of random builds

·       A plan for handling non-repeater blocks

The type of plane a team typically uses affects the way it builds every formation.  Left-door planes such as Twin Otters, common in theUSA, result in a left-handed continuity plan.  Many European teams that mostly use Porters use right-handed continuity plans.

The exit has another effect on all the builds, both randoms and the initial build of blocks.  Most continuity plans select a primary (or "A") build which corresponds to the preferred exit.  This way a team does not have to learn two different builds for exit and terminal.  There are exceptions, particularly blocks where the preferred terminal engineering does not provide an easy exit.  In these cases, some teams choose a "fire and forget" exit, where they exit a formation one way and perform it another way for the rest of the skydive.

The number of alternate random (and block) builds a team chooses to include in their continuity plan should depend on the amount of training they are doing.  A team doing 100 jumps over the year does not have time to learn a wide variety of builds.  A team doing 1000 jumps per year will see many different combinations and find many opportunities to take advantage of different builds which are more efficient in different situations.

Non-repeaters:

A major element of continuity plans for the advanced/open dive pool is the handling of non-repeater sequences, also known as slot-switchers and mirrors.  Some blocks result in one pair of piece partners being switched, relative to the other pair.  These are called slot switchers, and as of this writing include blocks 3, 10, 12, and 16.  Some blocks result in both pairs being switched.  These are usually called mirrors, and as of this writing include blocks 5 and 17.

Two continuity plans see common use in modern 4-way:

·        Front pair with mirrors

·        Mirrorless

In the first, older plan, the front pair (outside center and point) take the memory in the slot switchers.  In other words, the point becomes the outside center, and vice versa.  When a mirror block is in the dive, everybody stays in their slot, and everything switches from left to right, or vice versa.  This is the origination of the term "mirror".  So the back pair (inside center and tail) learn their jobs in normal and mirrored configuration, and the front pair have to learn their job and their partner's job in normal and mirrored configuration.  This plan runs into trouble when a dive includes both a slot switcher and a mirror.  Then the back pair have a mirror, and the front pair have to handle slot switching and mirrored pictures together.  This results in a long, complex sequence and frequently unfamiliar jobs for the front pair.

The mirrorless plan simplifies engineering significantly.  Again, the front pair take the memory in the slot switchers, but when a mirror comes up, both pairs switch slots - the inside center becomes the tail, and vice versa.  So there are no mirrored configurations to learn; everybody learns their piece partner's slot.  When a slot switcher and a mirror are in the same dive, the back pair has a two-page slot-switching sequence, and the front pair has only a one-page sequence.  The only teams for whom this plan is inappropriate are ones where the centers have a significantly higher fall rate than the long axis jumpers.  In this case, putting both point and tail in the center can result in their teammates struggling with the fall rate and even going low.

A "swing move" occurs when a dive is engineered to eliminate a slot switch between formations.  For instance, at the close of block 12 (bundy-bundy), the point flyer coming into the center at the close of the block can keep a bit of momentum and move away from the center during the following transition.  The outside center also maintains rotational momentum and dives into the center, putting them back in their original slots in the next formation.  When deciding whether to use a swing move in a dive, a team must balance the benefits (memory and familiarity) of eliminating a long sequence against the frequently longer move required to make the swing.

A popular means of dealing with exiting slot-switcher blocks is to exit them in switched configuration.  This way, when the hill block completes, all jumpers are in their home slots.  Then the first page is in A slot, and the dive will always include at least as many A-slot pages as B-slot, making the maximum use of job familiarity. 

Some less popular continuity plans include:

·        Front and back pair with mirrors

·        Center or outside solutions

In the first, the back pair will take slot switchers on some single-pair slot switchers such as block 16, but mirrors are still used often to handle blocks 5 and 17.  This plan originated through an uncommon engineering of block 13, where the formation is curved instead of straight.  This makes for a more efficient but awkward build and a more difficult block, and switches the back pair.  This plan is not recommended for most teams.

In a center solution, a mirror is handled by having the inside center and the outside center switch slots.  An outside solution switches the point and tail.  This plan involves numerous complications and few perceptible benefits.

Here's to a great season in 2008!

-Mike