Talking about Jonas and his legacy in the boomerang world is not surprising. Almost everybody recognizes his world-famous composite MTA and they still flying in so many tournaments after all these years. Jonas opened the path for composite construction decades ago, and many of us now still trying to discover all the details about his boomerangs.
During the 2020 virus outbreak I had the chance to talk with Jonas about his point of view on many topics, boomerang history, construction technique and future.
Hi Jonas, please tell us who you are and how/when you got involved in boomerangs.
Hello Alejo. My name is Jonas Romblad. Boomerang people may know me for the fiber composite MTA boomerangs I was making from 1991 to 2000.
I got involved in boomerangs through a book and the help of my father. As a child, I was often browsing through the local libraries. One day I came across a very short book on boomerangs by Rutger Staaf. The book had a plan and my father helped in making a boomerang from leftover plywood from a dingy he had built earlier. The boomerang flew well taught me the basics of throwing and catching. I was probably around twelve years old at that time. One day the boomerang got stuck high up in a tree and was damaged in the retrieval process. I tried making a second boomerang from the same plan but made a few mistakes, including swapping the undercut around. As a result the supposedly identical copy did not fly well at all. Both boomerangs ended up in a drawer and were forgotten for a few years.
When being around 14 I found the two boomerangs again and got curious why one worked and the other did not. This prompted more experimentation and I started actively searching for information on boomerangs. One thing leads to another and I found out about the world of boomerangs and the boomerang throwing family.
How were your early experiences meeting the boomerang family? any memories from the boomerang Swedish scene back in the day?
The Swedish boomerang scene was very small when I was into boomerangs. Apart from a few people who threw for a shorter time it was pretty much Ola Wahlberg and me. Ola is a very nice guy and it was unfortunate that the geographical distance between us made collaboration difficult. Ola was living on the west coast of Sweden and I on the east coast so we rarely met. As a result, my early experience with the boomerang family was mainly abroad, first through correspondence and later on travels.
My high-school library had a subscription of Popular Science and one of the issues appeared a small advertisement from “the Boomerang Man”, Richard Harrison. Following this thread I started gathering information about boomerang throwing through books and the Many Happy Returns newsletter. I wrote to various people who appeared in the books and newsletter with questions about boomerang making and throwing. As it happened, my initial contacts with other boomerang throwers were biased toward North America. Everyone I contacted was very helpful and happily shared their thoughts and knowledge. This open attitude is one of the very nice things about the boomerang community.
After finishing high-school I decided to make a travel in the USA and try meeting some of the people whom I had been corresponding with as well as other people I was interested in meeting. To make a long story short I ended up travelling across the USA on Grayhound bus for a month, going to two boomerang tournaments and meeting with people like Chet Snouffer, Betsy Miale-Gix, Mark Weary, Gary Broadbent, Bob Leifeld (Chicago Bob), “Rev.” Jim Schramm, Steve Kavanaugh, John “MoleMan” Anthony, Michael “Gel” Girvin, Mike Forrester and many others. The atmosphere was extremely open and friendly wherever I came. Many people hosted me in their homes on short notice. To this day I am very grateful to all the people who made the travel a fantastic boomerang journey which sparked a long lasting interest in boomerang throwing.
Before being well-known for your MTAs, you were really interested in wooden in-lay boomerangs, Can you tell us a bit more about it?
I have always enjoyed woodworking. At some point while experimenting with applying veneer to boomerangs I tried making some decorations by putting small pieces or strips of wood into the boomerang. It worked out well and I continued experimenting. The idea of using the “palette” of wood colour and -structure to create decorations is intriguing. Later I have read about the two different methods of making decorative inlays which can be described as the “jigsaw puzzle” type method used for furniture and the “piece by piece” way used for musical instruments. Both methods have their virtues but for the boomerangs the “piece by piece” method felt more appropriate.
On a side note, around 2007-2009 when living in Denmark I happened to get in touch with the only Danish woodworker doing wooden inlays as a full time job. Although close to retirement he was giving courses a few times per year in a small town way out on the Danish countryside, teaching the “jigsaw puzzle” method. I had the opportunity to attend a few of his courses which were very fun and educational. However, it is now several years since I did any inlay-work.
How was your first contact with MTAs, why do you find them interesting?
This was the time before the internet and my main source of information was the printed boomerang newsletters, in particular the USBA Many Happy Returns. So, my first contact with MTAs was articles and plans.
For me, MTAs are a bridge between boomerangs and model aircraft. In model aviation, many competitions disciplines are focused on long flight times and maximizing flight efficiency. I have a fascination with flight and the challenge of improving efficiency appeals to me. MTAs simply fit very well into these fields of interest.
Which was your aerodynamic approach to design/make MTAS back in the day?
I can not claim to have had an aerodynamic approach to MTA design. In those early days the published information suggested that an MTA had to look in a certain way so I started there and made small modifications step by step. Tuning was kind of a mystery and what turned out to fly well for me was very different to the few measurements of MTA tune that was published. Relatively small MTAs with low weight seemed to work for me and I kept to that concept. If I had not started making boomerangs in molds I would probably have experimented more with shapes and tunings. Instead, I stayed with the same shape and tried improving the performance by altering thickness, weight and weight distribution.
Tell us about your famous MTA design, experiences, models, Great flights, anecdotes.
Ted Bailey was the guru of MTAs at that time and his “hockey stick” shape was a great source of inspiration for most MTA throwers at the time, me included.
When making moulded MTAs, shape and airfoils were no longer parameters which could be easily changed. However, the thickness, total weight and weight distribution could be influenced by the manufacturing technique and the materials used. I have also tried a number of things out of curiosity and just for the fun of it. A hollow boomerang to save weight turned out too light and too flexible. I have a glow-in-the-dark MTA and a number of attempts using different Kevlar, fibreglass and carbon fibre materials.
The fields where I did most of my MTA testing had very few thermals and there were not many spectacular flights. My most memorable MTA flight was with the wooden predecessor of the composite boomerangs some time around 1990. I was throwing on a large open, grassy area in Stockholm called Gärdet. Suddenly the boomerang caught a thermal and started drifting off the field. In the direction of the wind were office buildings, 3-5 stories tall. Among the buildings was the Swedish Defence Material Administration, a building with strict security where it would be very difficult to retrieve a lost boomerang. The MTA drifted two blocks along a street and came down in the middle of a street crossing. Luckily, there was so little traffic I was able to make a catch. I have forgotten the flight time, but I think it was around two minutes. This is still my personal best MTA flight time.
Two happy MTA anecdotes form the World Championship 1992 in Hamburg, Germany;
The practice day(s) of the tournament were warm, sunny and humid. One of the US throwers, may have been Doug DuFresne, had bought an MTA from me the first day and after a few hours, he came back with a puzzled face. He told me the boomerang had worked great then he got it but now something had changed and it would no longer stabilize in a hover but get unstable and come crashing down. He had not tried to change the tune of the boomerang and asked desperately what he had done wrong. Inspecting the boomerang quickly gave a hint. The grass was very wet and to get a more safe grip, a square piece of electric insulating tape had been added to the top and bottom of the leading arm tip. I suggested removing the tape. Since weight-tuning of MTAs was not well known at that time he gave me a somewhat skeptic look, but went ahead and tried. MTA boomerangs can be rather sensitive to added weights and the electric tape which was added to the leading arm tip was enough to make the boomerang lay down too fast for a safe throw. The remedy was successful and he came back with a big smile on his face and a working boomerang.
The weather on the tournament days of the championships was horrible. The temperature dropped 10-15 degrees C, it was raining and the wind was howling. The throwing circles turned go mud. Someone, I have forgotten who, was using one of my MTAs and got blown way out of the 100m circle, far enough to have the boomerang land in a small lake. Assuming a carbon fibre boomerang would sink, he regarded the MTA as lost. Later he told me the story about the sad loss of the MTA. When he found out that my MTAs float in water he went searching the downwind shore of the lake. After about half an hour the thrower came back with a happy smile and a retrieved MTA.
You are an aerodynamics specialist, how did this help you to design better MTAS?
Aerodynamic knowledge has not helped much at all, I am afraid. The thesis by Felix Hess gives some hints of how tuning for the climb phase works in very general terms, but it does not help finding an optimum boomerang shape or tune.
In fact, the more I learn about aerodynamics, the more respect I get for the complexity of the boomerang in general and the MTA in particular. MTAs operate at low Reynolds numbers (small wings flying slowly) which probably means there are laminar separation bubbles in the outer parts of the arms. There are regions of both separated and attached flow and the rotation influences the flow. In the climb the flow is likely to be affected by unsteady aerodynamics due to the fast rotation and forward movement. Just one of these phenomena is enough to make the flow situation a challenge for an aerodynamicist. On an MTA we have all of these phenomenon and they most likely interact with each other!
Do you think Is there yet room for improvement in MTA performance-construction?
It may be bold to say since I have been away from boomerangs for almost 20 years, but I think there is. At the time I dropped out of boomerang throwing the maximum flight time in tournaments was often determined by the wind and the 100 m circle. Most MTAs, if seen from above, flies more or less an O-shaped pattern and then start to hover close to the thrower. However, if one could make the boomerang fly a 9-pattern, starting to hover significantly upwind of the thrower the flights could be longer and still be caught inside the circle.
The idea is not new. However, most attempts I have seen have the MTA travel far upwind but still return within 10-20 meters from the thrower. I was aiming for a hover significantly further upwind but I never figured out how to do it.
…but maybe this is common practice nowadays?
Makes sense to compare the aerodynamics of hovering MTA to the aerodynamics of an auto-rotating rotor?
In hover I think it does, at least if comparing with autorotating seeds which also hover. In both cases the rotation is maintained by acting like a “rotating glider”. Autogyro aircraft also autorotate but their normal mode of operation is not hover.
Even to these days your composite MTAs still being a reference in the boomerang sport, Can you explain to us how was the process of developing them?
When starting to learn about MTAs and how to tune them I found it troublesome that the wooden MTAs would not stay tuned and always require tweaking. From aeromodelling I had some experience with composites and with this as base I set out to make an MTA which would stay in tune. The first attempt based on spherical tuning and a very simple mold was only partly successful.
For the second attempt, the main features and tune of a good wooden MTA was carried over into a rigid mold. This mold tuned out very well and after further experiments with materials, manufacturing techniques and weight distributions the composite MTA you have seen emerged. I am omitting many little trials and failures here but all in all the development went surprisingly well, in particular considering the uncertainties of what a good tune would look like.
The selection of materials was very exquisite, even now Composites MTAs still using similar materials, Do you see a new revolution in materials in the near future?
I do not see a revolution in the materials as such but more in their availability and processing. Carbon fiber is still the first choice for low weight and high stiffness, but nowadays one can find much thinner weaves than when I was making MTAs. Prepreg, weaves pre-impregnated with epoxy are starting to become available to hobbyists and the thicknesses of the available materials are coming down to what would be useable for boomerangs. Carl Morris has done some very interesting experiments with foam cores for MTAs and he made a mold the tuning could be adjusted. Those may be directions in which to further develop composite MTAs.
How many molds you did before achieving a good one?
I got lucky and the second one I made turned out very well. The first one was a very crude mold where the bottom half was a block with a spherical shaped top and the upper half was cast from polyester putty. The mould release used for making the boomerangs was not good enough so very quickly a boomerang stuck in the mold and had to be hacked out with a chisel, destroying the mould. However, the results were promising enough to make me want to try a “proper” mold.
Back in the day, when you were producing your MTAs, all of them came from a single mold? or did you use several molds?
I used a single mold. All in all over 370 boomerangs came out of this mold, an unusually high number considering the materials the mold is made from.
How was the result of the experience with the kevlar ultralight versions of you composites MTAS? Can you tell us about the advantages of these materials? Did you prefer them over the black versions?
My MTAs appeared to perform better if they were lighter than my “standard” weights or around 18 grams. Since I could not find carbon fibre weaves lighter than the ones I was using, the next lighter weave was Kevlar (Fibreglass was not stiff enough)
Trading weight for stiffness, I ended up with MTAs of around 14 grams but the flexibility meant a full power throw was only possible holding the dingle arm. Personally I find my 12-14 gram MTAs a bit too light and the marginal stiffness increases the risk of a bad throw in tournaments. Attempts below 10 grams have had too low a spin-rate in hover they never got high enough for good flights.
Nowadays lighter carbon weaves are available and I see no advantage of using Kevlar in MTA making.
Can you describe the process you used for laying up the boomerangs? Did you vacuum them? Post cure them?
The process is not sophisticated. In short, the boomerang consists of two hand laid up shells with a filling of microballoon/epoxy mix.
First epoxy is brushed into both mold halves. The weaves are put in and impregnated with the epoxy. There is an outer layer with fibers running along the arms and an inner layer with +- 45 deg. fibre direction. After letting the first batch of epoxy get a bit sticky, the cavity of the mold is filled with a mixture of fresh epoxy and a light filling powder called micro-balloons. The top and bottom halves of the mold are closed tightly which squeezes excess filling materials out. No vacuum or other sophisticated techniques are used.
To speed up the curing process and to improve the mechanical properties of the epoxy, the curing was done at temperatures around 40-50 degrees C. I had a heater-box which maintained 50 degrees and the mold would be kept in the box both before use as well as during the curing of the MTA so the mold was also warm during the laminating work.
I heard a rumor about saying the molds were destroyed after you stop producing them, is that true? Do they still exist?
My production MTA mold still exists. Apart from being a bit worn it is still in good shape. I keep it in case I would like to make more MTAs at some point.
The craziest story about your composite MTA?
The craziest story is probably the 17 minute MTA flight by John Gorski and that I was lucky enough to be there to see it. However, that story is told in detail in other places.
A less crazy but still funny story comes to mind;
In 1994 I was doing the experiments for my MSc thesis at the low speed wind tunnel at the Royal Institute of Technology in Stockholm (not at all related to boomerangs). This was the time before mobile telephones became common but there was a telephone at the tunnel. A friend of mine had told the ladies at the switchboard the two of us could be reached at this telephone. Still, calls were rare.
One day the phone rings and I answer. On the other side a gentleman politely introduces himself, saying that he is calling from the Japanese embassy. In Stockholm, many of the embassies are located close to an open, grassy area called “Gärdet” where we would go fly kites, model airplanes, boomerangs and such. Sometimes our “toys” would end up landing inside the fences of one of the embassies, so my first thought was “oh, I wonder if I have done something wrong…”.
After confirming my name the gentleman from the embassy explained that he was the secretary of the Japanese military attaché in Sweden and that the military attaché was looking for someone with my name at the Royal Institute of Technology. At this point I was certain I had done something seriously wrong.
It turns out the military attaché was a friend or colleague of Mr. Hiroyuki Murata who was deeply involved with the Japanese boomerang association. Mr. Murata wanted to buy a number of MTAs for his boomerang club/team. Since he did not know my address but had connections at the Swedish embassy, Mr. Murata asked if they could help contacting me. It worked out and a number of my MTAs ended up in Japan. A few years later, in 1996 I had the pleasure to meet Mr. Murata and his very friendly boomerang team-mates at the world championships in Saint Louis, USA.
You are also involved in F1D planes. Tell us about that experience.
F1D is the cryptic name of a competition class for model airplanes flying indoors. These airplanes are powered by a wound-up rubber band which turns the propeller and they fly freely without any radio control. I have been fascinated by indoor free flight models since childhood and F1D is for indoor modelling what Formula 1 is for car racing or America’s Cup is for sailing. It is difficult to convey the impression of seeing these aircraft fly, but in my eyes they are both beautiful and fascinating at the same time. Imagine a model aircraft with 55 cm wing span and a length of 80 cm flying completely silent, slower than walking speed. The propeller may take up to two seconds to complete one revolution and flight times can be over half an hour. The total weight of an F1D model is less that two grams and the transparent covering material shimmer like soap bubbles.
I have been flying indoor free flight models for many years and F1D models for almost 20 years. Like with boomerangs, indoor flying is a small and very friendly community of enthusiasts who are happy to help others. For a taste of indoor free flight, take a look at the video a friend of mine made as an invitation to a competition several years ago:
Will we see you again on a boomerang event one day?
Right now my focus and inspiration are elsewhere but who knows what the future will bring.
What do you think about the Bepponas composite MTA?
The Bepponas is a very nice MTA. The fight pattern of the one I have tried matches very well with what most of my customers seemed to like and it is nicely forgiving. My personal taste is for an MTA to lay down a bit faster during the climb which requires the boomerang to be thrown at a higher elevation. However, many throwers are uncomfortable with this kind of throw and the accuracy of the throw required for a smooth transition to hover is higher than with the Bepponas. However, the rate of lay-down can be increased by adding small weights at the tips of the MTA, so there are ways of adjusting to your personal taste.
Didier Beral Throwing a Bepponas MTA:
Any advice for beginners?
Get in touch with the “boomerang family”. It is a very friendly bunch of people who will happily share their knowledge and enthusiasm. If there are no other throwers in the area, use e-mail or other means to get in touch.