Before I begin explaining, let's check if your boomerang is in a "neutral" tune: Place it flat on an even surface and press lightly down on the elbow area ( the part where both arms meet ): now both arms should be either resting flat on the surface or the tips should be pointing upward slightly.

WHAT AND HOW YOU TUNE:
There are only very few things we can do to the boom directly - mainly bending the arms up - or downward ( adjusting the so-called dihedral , i.e. the angle above or below the straight=neutral position),and twisting them clockwise or counter-clockwise ( altering the so-called angle of attack, i.e. the angle at which he leading edge= front-edge of the arm cuts through the oncoming air-flow) - and adding weights and flaps to add momentum and drag.
By doing so, we can alter the performance of the boomerang drastically. It only takes very little bending or twisting to result in a very significant change of the trajectory, so this is what we want to keep in mind, before we start altering the dynamics of a given boomerang: A LITTLE GOES A LONG WAY! In bending this means, altering the bend ( up or down ) by just a few degrees will do much more than you would expect PLUS, when you do the first few test throws after bending and you are not happy, you can always bend some more.

PAXOLIN, the material that almost all of my competition and high-performance-rangs are made from, lends itself to experimenting with bend-tuning, since it is quite flexible, yet strong enough to maintain a certain amount of bending. However, it is not so hard to break this material, specially when it gets colder in Autumn or Winter, so: the colder it is, the more careful you have to go about with any bending with this material.

 

In moderate temperatures this metarial is amazingly flexible.However it is not unbreakable- specially in cold tempeartures (near and below freezing)!! Therefore: the colder the environment, the more cautious you have to be while bending/twisting. Better to pre-bend inside, before you go out for testing. Breathing on the rang also helps, as does a water kettle or a hair drier- both these may affect the paint however!

BENDING

- this chapter and the following are mainly aimed at getting the most distance out of your
- ( distance) rang, but of course any of these steps applies to any boomerang you want to alter.
BENDING UP = adding dihedral of one or two wings generally results in
- a higher trajectory
- earlier lying down and thus a shorter circle
- a longer hover.
When you add dihedral to the lift arm ( the one one the right when the boom lies flat on ist back and you look on to it ) , the rang will tend to lie down sooner and then zoom higher. This means that you have to alter your throw to a more vertical and higher release. You will get a higher, more cicular trajectory with a nice hover for an easy catch at the end of the flight.
Adding dihedral to the dingle or trailing arm ( the left one when you look onto it ), you will get a higher trajectory in general and a great hover - at the expense of a lot of the distance.
SO: if you wish to tune your boomerang for good catchability and you don't have to worry about wind - this is something you'd want to try.

Accordingly BENDING DOWN one or two wings results in
- a lower trajectory
- later lying down and thus more distance
- reduced hover.
Bending down the wings results in a flat, more elliptical trajectory, with a short or no hover at all - thus making it very interesting for
- long distance
- wind throwing
- fast catch
By reducing the lie-down you create more distance and a figure-eight-shaped flight, which helps a boomerang to cross over a line drawn across the point of release ( long distance ). It also helps any boomerang stay lower and thus being less affected by the wind - which is doubled by the fact that a reduced or eliminated hover keps chances lower of the boom getting blown away during the hovering phase - all at the expense of heavily reduced predictability and catchability.
In order to adapt your thro, you have to give the rang more layout ( tilt ) and throw lower and a bit harder too, possibly a bit more into the wind too. REMEMBER THAT AFTER EACH TUNING STEP YOU ARE THROWING A DIFFERENT BOOMERANG AND THAT YOUR THROW HAS TO BE ADJUSTED ACCORDINGLY.

Example: in the fast-catch event you want a rang that stays at the same level throughout the flight, and you want it fast = not lying down and zooming up: you want it to come in almost vertically, like at the moment of release. So: you play with bending down on one and then the other arm, until you get to the piont, when the boom doesn't crash anymore halfways through the circle - until it stays staedy and vertically. And you will soon see that it is a matter of playing in tiny steps, until you reach the final result that you desired.

TWISTING

By twisting one or both arms positive=counterclockwise or negative= clockwise ( adding positive and negative angle of attack ) we can change :
- spin rate and wind-stability ( twisting counter-clockwise reduces spin-rate and makes the rang more wind-resistant )
- distance ( twisting counter-clockwise reduces distance )
- liedown ( twisting counter-clockwise reduces or elimuinates liedown )
- type of trajectory ( twisting counter-clockwise results in a lower, circular flight-pattern, clockwise in an elliptical flight with a steeper ascent )
GENERALLY: to adjust your throw after twist-tuning:
- after a counter-clockwise twist you normally throw a bit lower and with abit more tilt, possibly a bit more into the wind.
- after a clockwise twist you throw more vertically and a bit more off the wind

EXAMPLES:
1. no wind: your favourite 40m rang doesn't make the complete retutn home to you, no matter how hard you throw. The dingle arm needs a counter-clockwise twist, which reduces distance a bit, but which helps the rang to "walk" home (this can be supported by a bit of positive dihedral on the lift arm).
2. MTA#1: your mta rang soars up quickly and never settles into a steady hover, bur keeps rocking back and forth and loses height quickly, even though you throw vertically: try and give the digle arm a positive twist and thriwing straight vertically, your mta will tend to climb more steadily and stettle into a better hover. If you twist too much, you will reduce spin too much, so be very careful again!
3. MTA #2: your mta doesn't gain enough height and loses spin too soon: add a bit of negative twist to the lead-wing and throw a bit higher: this will increase the lie-down and the spin rate as well ( if the rang climbs too much and flips over, try and reduce the upward-bend of either arm a bit )
4. Distance: you are about to fine-tune your distance-rang for the full potential, after you have mastered the throw. First I would add a bit negative twist to the lift arm ( tiny steps again!) and throw with a bit more tilt. Then add a bit more, just until the rang doesn't turn anymore. THEN: add a bit of positive twist again, just until the rang turns again ( dajust the throw woith morew tilt and a bit more into the wind ). Step 2: next you can slightly bend down your dingle arm ( and adjust by giving it even more tilt in the throw and aiming even more into the wind ). If the rang doesn't urn anymore or keeps crashing on the way back, add a bit of positive dihedral to the lift-arm and throw slightly higher.

These are just a few little examples to get your imagination started. You really have to play around with one and the same boomerang a lot to learn these things. And, MOST IMPORTANT: only alter one parameter at a time: Just bend on one wing and see what happens when you have adjusted your throw and all, and then continue. Otherwise all you do will get blurred and hard to repeat.

 

Copyright: Volks' BlueStar Boomerangs 2007 .