A jet with a difference. It’s a Boomerang!
By Alan Cardash (Written in late 2002.)
It all started back in 2001 when my Kangaroo jet trainer and the Simjet turbine in it met a sad and very total end shortly after my return from Florida, due to radio failure (Honest!).
In an extravagant moment I’d decided to go to Florida Jets early in 2001. Seeing all those impressive models with their superb paint jobs made me really ambitious. I wanted to move on to something like a BVM Bandit, but a little more modest in cost.
I replaced the Simjet with a JetCat P80 and came across a Cyclone kit on special offer. I put a lot of effort into the finish and detailing and even went to the extreme of joining a club which flew off a hardtop runway, as it was obvious that this model could not be flown from the somewhat bumpy grass field used by my club.
It was beautiful, but after flying it for a short while, it dawned on me that this was not my kind of flying. The tension of a flight with a model capable of close to two hundred mph - and of high value not just in cash terms but in the huge amount of building and detail finishing hours put in - was not for me. In addition, I found the limited maneuverability soon palled. Apart from rolls, huge loops and sweeping turns, it’s mainly the amazing high speed that gives the pilot a kick. Horizon to horizon in five seconds. Wow! A huge and exciting thrill, it’s true, but for me, limited appeal after the twentieth low pass. I wanted my plane to be able to do more and to be capable of flying repeatedly from a bumpy field without needing constant attention to the undercarriage. I sold it with no regrets.
I decided to design my own jet. The characteristics I wanted were quickly settled in my mind. The plane had to be capable of taking off and landing comfortably from our typical English club field. If the ground was not smooth should it still be able to get off with a minimum of fuss, even in longish grass. A short take off and low landing speed were essential. Flaps that would double as air brakes for controllable but slow, steep landing approaches. In addition I wanted a good aerobatic performance but not a tricky flying, jumpy model. This meant thick wings with a generous wing area and a reasonably light wing loading. The top speed should be quick and jet like, yet obviously was not going to be ballistic. But, most importantly, this was going to be a jet that would be real fun to fly!
Simplicity of structure came high on the list. The wing loading had to be around two pounds per square foot maximum. I knew that a model this size would come out over twenty pounds so needed a wing area of over 10 square feet. I chose good thick wing and tail sections and decided on a span of 96” with a similar length. To avoid using a tail pipe, twin booms were the obvious starting point. This also meant that the model could be made to break down to fit easily in my car.
The thrust line would be dead on the center line of the wing, tailplane high to escape the hot jet exhaust. A simple Coke bottle fuel tank. As well as a long moment arm, areas of tail and fin to be generous with thick sections to ensure steadiness in the air and smoothness of flight. Large control surfaces all round. I drew up the wing plan, and sent off for a pair of foam wings and a tailplane to be cut. Fixed landing gear with relatively big wheels, of course. I drew the fuselage and boom sides directly on to the wood and from that, the formers more or less designed themselves. The first Boomerang emerged a few weeks later.
From the very first flight it was obvious that here was a plane that did all I had wanted and then some. It took off from the grass in under 50 feet and had real presence in the air. On low throttle it floated along and with the flaps down the trim hardly changed and landings were slow and easy. It weighed in at 25.5 lbs dry which was pushed along nicely by my JetCat P80 to begin with and later by the JetCat P120, with 27 lbs. of thrust giving stunning vertical performance.
At one of the Jet Modelers Association meetings I asked Ali Machinchy to try it out and I just stood beside him amazed when after a few provisional feelers he proceeded to push the Boomerang through maneuvers no one thought a turbine model could do. My heart was in my mouth, not because of his flying, his skill is fantastic, but because I just hoped the plane could take all the stresses he put it through. I had obviously built it right as there were never any problems. He loved it and we became a sort of team at meetings. We both flew it but I got such a kick out of watching Ali push the limits that he flew it more than I did! Jet flyers started to ask if I was going to kit it.
I was flying on the display line at the 2001 British Nationals in August. Ali was there and after I flew my usual conservative flight he took it up and put Boomerang through its paces in flamboyant style several times, much to the delight of the spectators. It was a fabulous weekend, topped off by the award of the prestigious Windsock Shield trophy to myself for the design, though I felt it really ought to have gone to Ali for his superb flying. That didn’t stop me taking it home with great pride.
I wanted to go to Florida Jets again, but this time to fly, not just watch the others. Ali was keen and we booked our flights. I had a proper light weight box made to carry the plane and in February 2002 we arrived, with Boomerang causing curious looks from the other guys there. Frankly, I was a little embarrassed to be turning up with my big, basically ‘fun’ model covered in plastic film amongst all these absolutely beautiful jet models with their superb detailed finishes. I think the paintwork on most of them cost more than my whole plane! However, I kept reminding myself that Boomerang could fly rings around all of them and so we started up and Ali taxied out to the runway.
Mostly curious looks from the fliers there turned to open mouthed disbelief as he went into a routine that included rolling loops and knife edge figure eights, not to mention spins, hammerheads and a hesitation snap rolling circle. I looked around the crowd line and everyone had stopped to watch. Believe me that was a good feeling. One of Ali’s flights is featured on the SKS video of the meeting.
The whole of that weekend was marked by questions about the model and when was a kit going to be available. The pressure was on to make a decision. Everyone at that event was really friendly and helpful. Frank Tiano had gone to the trouble to arrange a loan to me of a 72 Mhz. TX module and RX. Nice memories stay with me. We made some good friends. And at the dinner on Saturday night we were presented with an engraved ‘Exceptional Performance Award’. Despite an untypical rainy weekend, Florida Jets was a wonderful meeting and we plan to go back again in 2003.
Back in England the plane soon had over 100 flights under its belt. I realized that in my awe of jet flight I had ‘over engineered’ it in many areas. Keeping the design outlines the same, I rethought the basic structure, with the possibility of a kit version allowing provision for retracts etc. just entering the back of my mind.
I set to and finally planned out the kit version. I had never kitted a plane before and after months of hard work and brain strain I realised why kits cost what they do. I modified the structure to make it lighter. A test model was built from the kit parts and came out at an all up weight of just over twenty pounds. Flight performance was better than ever now. More changes were made to simplify the construction. Finally the whole thing was ready to put together and I started production. We’re now onto the second run. They’ve gone to seven states in the USA, to Cyprus, Europe the Middle East and Australia, not to mention to flyers in Britain of course. More awards have been won at jet meetings in the UK and in Europe too.
At the 2002 British Nationals, Ali twice shut down the Jet Cat, glided for a while and then restarted the turbine during flight. I think that’s a first to be verified at a public jet meeting. He keeps stretching the list of maneuvers Boomerang can do. Another modeler in Michigan has told me he plans to put skis on his Boomerang and fly it from the snow this winter. It’s proving to be a versatile model.
What next? The feedback from flyers is great and Boomerang is turning into a real success story. Long may it continue!
Alan Cardash 2002
The very first Boomerang Jet.
Alan and Ali at Florida Jets 2002