I have been making and throwing boomerangs since 1970, MTA boomerangs since
1992 and also Composite boomerangs since 1992. Therefore I could say that my
latest Composite MTA boomerangs "Gradus", "Sensor", "Primer" and "Trigger",
are the result of many years of investigation and experience. Step by step I
have always sought the best solutions to theoretic and practical problems -
principally in two directions - aerodynamics and composite constructioIn
technology.

Aerodynamic Design
In aerodynamic design I have experimented with the outline shape and also
with the arm profile. The shapes of all three MTA twoblader models appear so
simple and familiar. But they were developed and optimised after much time
in the building and testing of many prototypes. During the tests many MTAs
(more than 20!) - plywood prototypes and Composite copies, were lost into
the blue! Two important steps on the way to the Composite MTAs production
were:
1. The series of "Magic", "Topic" and "Impulse" MTA boomerangs made from
1.55 and 2.00 mm thick fiberglass/epoxy/metal-plates (1993-95) and
2. The moulded in matrix Composite "Vector" MTA boomerang (1995-96).

I have already published my ideas in the area of boomerang arm profiles in
the "Swiss Boomerang Newsletter" (1/2000, pp.19-24 & 2/2000, pp.10-16). My
theory indicates that the leading arm have to work mainly for lift and the
trailing arm - for stabilization. So it is better for both arms of an MTA
boomerang to have different profiles. In the models "Gradus" and "Sensor 2"
the leading arm has a slightly curved (cambered) profile underneath. I know
that earlier Wilhelm Bretfeld and Adam Mueller (Germany) had already
experimented with hollowed underside of MTA boomerangs. I decided to use new
and different profiles for the both arms just after the effect was
theoretically proven. Very encouraged for me were the throwing tests'
results of "Gradient" MTA (developed in Nov.-Dec. 1999; span 330 mm,
thickness 3.2 mm, mass 18 g; wich plan was published in Swiss, Australian,
Duch, French, Italian and British boomerang newsletters in 1999-2000). After
many 1+ min. flights the "Gradient" second prototype was lost from the sigh
after 2 min. 30 sec. time aloft on the 03.12.1999. One of the next 5 plywood
"Gradus" prototypes was selected for series production on the 26.03.2000.
Although the theory was clear, the optimal arm profile was long sought after
- for the "Gradus" series alone three matrixes were made, whereby the arm
profile thickness and camber were gradually optimised. Now in the series
production is only "Gradus 2" with double reduced LA-profile' camber.

The next model - "Sensor" is a wellknown classic "Hockey Stick" concept. The
outline shape and tuning are from Manuel Schuetz's "Apollo 3" (ex-Swiss
MTA100 record - 55.52 sec., 27.07.1996, Bensheim, Germany), but the arm
profiles I modified according to my personal experiance. The "Sensor" is
produced todaay in two variations (in two matrixes) in series:
- "Sensor 1" with flat LA-underside and
- "Sensor 2" with cambered LA/elbow-underside.
Manuel Schuetz (Switzerland) was the first who accepted my ideas and now he
are manufacturing a Composite MTA boomerang (since 2001, Ted Bailey' "Wind
Sailor" shape, span 365 mm, thickness 2.75 mm, mass ca.20 g) were the
leading arm has a cambered profile. (Typical for the world boomerang-family:
I take for my "Sensor" the Manuel'shape and he followed my idea to make the
LA-profile cambered. We all together work for the progress!)

The third my Composite MTA model - "Primer" is a result of an another
concept. It's size and shape are near to these of "Gradus", but the
arm-profiles are quite different and near to the "magical" flat plate
profile (one of the "Jonas Composite" aerodynamics secrets!). Actually, the
MTA boomerang design story is an eternal pendulum movement between the "flat
plate profile" (first Bretfeld' plywood MTAs and first Heckner/Behrens
paper-phenolic MTAs) and the "flat-concave profile with turbulent leading
edge" (Bailey, Jones).

Of decisive importance to the flight path (flight distance, height and
hover) and also for wind resistance is the surface loading (boomerang'
mass-to-circle'area ratio). The arm bending and twisting of every one model
were optimised over a long time in close connection with the surface
loading! (Because Composite technology makes it possible to make an MTA
boomerang between 10 and 50 g in weight. Where in between does the optimum
lie?). For stable hover the models "Gradus" and "Primer" are balanced with
two micro weights - 0.4-0.5 g in weight, built in to trailing arm and the
"Sensor" and "Primer" with one micro weight, built near to the center of
rotation.

The used by me Composite technology was tested and optimised over many years
by the design and production in series of 6 different boomerang models:
- "Classic" (1991-92, span 395 mm, mass 68 g, 120 copies made),
- "Weekend" Hook (1992, span 318 mm, mass 50 g, 8 made),
- "Hope" V/Omega (1992, span 363 mm, mass 62 g, 8 made),
- "Vector" MTA (1995-96, span 310 mm, mass 28-30 g, 80+ made),
- "Legend" Hook (1991-92, span 305 mm, mass 52 g, 6 made) and
- "Aussie Stick" Kylie (1992/2000, span 560 mm, mass 350 g, 20 made).
The first matrix for the "Gradus" was ready on 03.04.2000, the first
Composite "Gradus" was built on 06.06.2000, "Gradus 2" on 25.10.01, "Gradus
1M" on 05.12.2001, "Sensor" on 22.07.2001, "Sensor 2" in September 2001 and
"Primer" on 02.11.2001.

Many boomerang designers/throwers from quite different corners of the world
are interested in my Composite MTA boomerangs. They also wished to know the
differences in comparison with the "Jonas Composite" - the model of the
pioneer in Composite MTA manufacture - the Swede Jonas Romblad (since 1991,
Bailey' "Wind Sailor" shape, span 368 mm, thickness 2.2-2.5 mm, mass 14-19
g; 1 min. 37.78 sec./European MTA100 record by David Hesse, 20.09.1997,
Burgdorf, Switzerland). I think, the aerodynamic and technology level of my
Composites are at least a couple of steps foreward on the eternal way
towards the optimum, but each thrower can decide himself on the result.

Construction, Materials
I didn't keep the construction of my Composite boomerangs a secret.
Each of them consists of two shells. Each shell consists of three to five
layers and is made in especially for each of these shell matrix from
different reinforcement materials and epoxy resin. For the reinforcement are
used products (fabric and/or rowing) of glass, carbon and aramid ("Kevlar"
TM and "Spectra" TM by "DuPont"/USA). The kind of each material and its
order in the shell are selected so that each materials give of their best
qualities for the strength and stiffness of the boomerang. The space between
the two shells is filled with a lightweight foam material or lightest balsa
wood from a very special selection, not like the "Jonas Composite" which
uses micro-balloons/epoxy mixture. I use materials that come from Germany,
France, Russia and the USA. All they are special materials that were
developed for building aircraft, sailplanes and aero-models and are of the
highest quality. In production some quite specialised and relatively
expensive tools were used, shears for cutting aramid, cutters for carbon,
scales with measuring accuracy of 0.1 g, vacuum pump, special oven and more.
For cutting the "Spectra" fabric I have to use a laser! After the closing of
the two shells the boomerangs were "baked" in the oven. Next the boomerangs
were left to "relax" from the high temperatures. Later the boomerangs were
tested many times in different atmospheric conditions (air temperature,
dryness and humidity, dynamic and thermal air conditions) and over different
times of day. During the tests the boomerangs were tuned using 3D/"Zig-Zag"
turbulators (already proposed by me to the boomerang world for 5 years).
With the relatively thin "Primer" it wasn't really necessary to use the
turbulators, but with the thicker "Gradus" and "Sensor" it was. To place the
turbulators right it was neccessery to investigate in advance the airstream
distribution over the boomerang surfaces. This experiment was started in
June 2000 and continues now. The picture of the airstream for the all most
popular boomerang shapes - Hockey Stick, V/Omega and Hook were already "got"
in the summer of 2000.

My Composite MTA boomerangs posses two most important qualities for every
one boomerang thrower:
1. They are tuned and retain the tuning durably - so that one doesn't have
to bend up or to twist the arms.
2. Throwing is relatively simple and with almost perfect classical style,
that is one holds the boomerang vertical and throws it about 45 up to 60
degrees over the horizon.

Care and Storage
For storage, transportation and throwing one must bear in mind that the
Composite MTA boomerang (as with all composite construction) is not
absolutely unbreakable and that they are sensitive to large temperature
variations. Therefore it is recommended that the Composite MTA boomerang is
transported and stored in a secure box and should only be thrown in a big
enough grass field.

What is typical for each of the three Composite twoblader MTA models:
* "Gradus" (span 333 mm, thickness 3.2 mm, standard-mass 19-21 g) because of
its dimensions and tuning it is most easy to throw and stable in wind.
-> Lee Ragsdale (USA): "The "Gradus" was the best investment I made in the
Ted Bailey' Fall 2000 Auction." ("Many Happy Returns", 82/Summer 2001,
p.11);
-> Andy Cross (Calgary, Canada) wrote me "I really do like your "Gradus"
MTAs. I think that they are one of the best, if not the best, MTAs currently
available." (28.02.2002)
-> Andy Furniss (England): "Every one penny of the "Gradus" price has it's
value!" (07.08.02, WBC-Kiel-2002);

* "Sensor" (span 363 mm, thickness 3.2 mm, standard-mass 20-22 g, for
stronger wind - up to 25-26 g) it most closely resembles the classical
plywood MTA well liked by some throwers, and partly also to the "Jonas
Composite".
-> Ted Bailey (Ann Arbor, Mi., USA) share me "I like "Sensor" better than
another "Wind Sailor" shape Composite MTAs. It is my favorite." (15.10.2001
and 30.09.2002);

* "Primer" (span 340 mm, thickness 2.5 mm, standard-mass 18-19 g) needs
lowest throwing power, but good coordination. The right "Primer" throw looks
similar to the throw of the lightest "Jonas Composite". After the throw
"Primer" climbes higher and because the weight/area-ratio lower is, it could
stay longer aloft. There were made and testet several havier "Primer"s with
mass up to 26-28 g. These are very stable in wind. One 27.5 g heavy "Primer"
savioured me and my Team (International Veterans) during the WBC-Kiel-2002,
hovering 30+ sec. in the Baltic wind. The heavy "Primer" will made only when
special ordered.
-> Didier Bonin (Quetigny, France) comented "... I tested it comparing with
the "Jonas Composite" and I can tell you this: the "Primer" is as good as
the "Jonas", as long in the air! Very very slow going down!... Also the big
point is: when you must difficulty throw the "Jonas" negativ, you can throw
the "Primer" easily more!!... Today was windy and it was not a problem for
the "Primer"!!" (20.11.2001).

Results
After so many words on design and technology, a little about experience.
What has been achieved in competition with my Composite MTA boomerangs?
- With "Vector" Michael "Gel" Girvin (Ca., USA) threw 43.19 sec. and won the
MTA event in a tournament in Allentown, Pennsylvania (summer 1997).
- Barnaby Ruhe (Pa., USA) wrote me "I won a few contests with one of your
"Vector" MTA's for big wind, until it flew away." (24.12.2001).
- One of the first "Gradus" (23.7 g heavy) thrown by me in the German
Championship in Muenster (June 2000) stayed in the air for 46.13 sec. and
that was good enough for only fifth place in the MTA event, but it was the
new Bulgarian MTA100 record.
- Using a "Gradus" (made in 2000), the American Lee Ragsdale won the MTA
event with three throws of 38, 46 and 39 sec. in the Georgia Tournament
(USA, April 2001).
- With a "Gradus" (made in 2001), the Englishman Andrew Furniss set the
British MTA Unlimited record with 75.41 sec. in the Trefriw Festival (UK,
August 2001).
- During the World Boomerang Championship in Kiel (Germany) the Frenchman
Michael Misslin threw with "Gradus" the French second best time in MTA
Unlimited - 92 sec. (02.08.2002).
- Ed ter Laare from Holland threw with a "Gradus" the 7th time in MTA100
Individual competition durung the WBC-Kiel-2002 - 43.40 sec. just 15 minutes
after he bought the boomerang;
- Throwing "Sensor 1" (25.0 g heavy) the Englishman Adam McLaughlin set the
British MTA100 record - 44.70 sec. in the Trefriw Tournament (UK, August
2002).

As I have already said, Jonas Romblad started making his Composite MTA
boomerang in 1991. Gary Broadbent (Oh., USA) began first to copy the "Jonas"
("Bonas", since 1998), later the Rod Jones' "Midge" and Fridolin Frost's
"Highlander" also. Harald Gerbig (Bavaria, Germany) was the second who tried
to copy the "Jonas" ("Pemulwuy", 1999). In the year 2000 Andy Cross
(Calgary, Canada), in 2001 also Manuel Schuetz (Gruenenmat, Switzerland),
Martin Laslett (Birmingham, England) and Oliver Couzi (France) started
making MTA boomerangs in Composite construction.
A new era has started in MTA boomerang technology and a competition already
exists. That pleases me personally. A creative competition is very healthy.
Only in that way can each thrower choose the best for himself MTA boomerang
- moulded in matrix or shaped of plywood, paper-phenolic, linen-phenolic or
carbon/epoxy-plate. And the best should win!

Parallel with the production of the three MTA twoblader models, the
Composite "Aussie Stick" was produced. This is a true-to-the-original copy
of an Australian Kylie (Perth Region, W.A.) from the first half of the
twentieth century. The first "Aussie Stick" prototype was made in winter of
1992. The construction has been optimised for a long time and now each
"Stick" is unique. My Composite Kylie is relatively light - it weighs "only"
350 g, it is however strong enough - as an "original" from acacia (Mulga)
wood and flew 80 and more meters in a steep straight flight. As with my
Composite MTAs, the "Aussie Stick" consists of 2 shells, each shell consists
however of more vacuum pressed layers - up to 10(!) of which the proportion
of E-glass is the largest. The two upper layers are formed from carbon
(black) and aramid (yellow or light brown), which is similar to the
arrangement of the plies in the Mulga wood.

My last MTA design is the "Trigger" triblader also manufactured of
Composites.
The "Trigger" story is long enough. I started experiments with unusual MTA
shapes in the early 1994. The plans of two of them ("Spiralic 1&2") were
published in the "Swiss Boomerang Newsletter" (2/1995, p.8). Many years
later, inspired by Manuel Schuetz on the 11.11.2001 I made the first
prototype of the "Trigger" - a triblader with typical for one MTA boomerang
flight characteristics. Up today are made more than 40 prototypes of
different materials (resp. different thicknesses and weights) with different
shapes and profilings. The "Trigger" shape is "creazy", but the profiling of
it's three arms is "more creazy". The "little secret" is the flat plate
profile with a relative blunt, but turbulent leading edge and a S-shaped
middle line.
The first times encouraged me were 19.91 sec. and 29.12 sec. with the #10
and #12 prototypes (01.03.2002). A little later with the #28 prototype I
reached 31.44, 32.82, 33.62 sec. in a middle wind. In the beginning of April
2002 I decided to manufacture "Trigger" of Composite. For the matrix was
selected the #29 prototype, made on the 05.03.2002 of 2.35 mm thick birch
plywood, 24.8 g heavy incl. 2.35 g balance-weights. The first Composite
"Trigger" was made on the 02.-03.05.2002. On the 13.05.2002 in light wind
and thermic the "Trigger #2" hovered 47.37 sec. and land in the
100-m-circle. Later I have with this sample as best 43.18 and 39.08 sec. For
the serial "Trigger" I have to use a new epoxy resine (German special
production for aircraft manufacturing) and a new filling material. The best
times I threw with the black carbon "Trigger #3" were 33.19 and 36.68 sec.
(09.06.2002). The "Trigger #7" was the first made of yellow aramid/black
carbon material with "snake skin" look. During the tests in light wind and
thermic it hovered up to 30.43 and 32.25 sec. without balance-weights
(10.06.2002).
During the WBC-Kiel-2002 several throwers threw with serial "Trigger"s many
times 40-45 sec. The best time aloft with "Trigger" up today is 2 min. 48
sec. - thrown by John Gorski on the 31.08.2002 in Delaware, Oh., USA.

What will be the next step? We will see. But for sure "THE BOOMERANG DESIGN
MUST GO ON!"

----------------------------
Sumarised 09.12.01-20.01.02;
Addenda finished 03.10.2002.

* This article incl. graphics is published:
1. In French in "France Boomerang Association Newsletter", 75/Dec. 2001,
pp.12-13
and in "Swiss Boomerang Newsletter", 2/2002, pp.8-9;
2. In German in "Swiss Boomerang Newsletter", 4/Winter 2001, S.11-13;
3. In Italian in "CLUB Newsletter", 36/Feb.2002, pp.10-18;
4. in English in "British Boomerang Society Journal", 21/Spring 2002,
pp.18-22.

** Information (incl. pictures) about my Composite MTA boomerangs (in
English) is published in:
1. "Bumerang Welt" (Germany), 2/1996, S.3-5; 3/1996, S.3-5.
2. "DBC Info" (Germany), 51/Feb.1996, S.22; 57/Oct.1997, S.25.
3. "Many Happy Returns" (USA), 65/Winter 1996, p.12; 82/Summer 2001, pp.11;
4. "Boomerang News" (USA, Canada), 21/Jan.1996, pp.5-6; 22/March 1996, p.5;
24/April 1996, p.5; 62/June 2001, pp.4-5; 65/Jan.2001, p.4; 69/Nov.2001,
p.3; 70/March 2002, pp.5-6; 71/July 2002, p.6;
5. "British Boomerang Society Journal", 20/2001, pp.23-24.

*** An article about the "Trigger" story will be finished and published
soon.