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Flying on Floats - An Article by the late Paul Haines.

Microlight Pilots come from a variety of backgrounds:- some have never flown anything, some are hang glider pilots frustrated by the wind never being "on" the hill, others come from a General Aviation (GA) background, and have become disenchanted with the upward-spiralling costs of flying thirsty twin engined machines, or are simply looking for more FUN in flying.

I first met Kevin Dennes when he came to complete his microlight pilot training at the Sydney Microlight Centre. Kevin has a vast amount of previous experience on single and multi-engined GA aircraft, and is no fool, but he wanted more fun in his flying - but safely, with proper instruction. Yes, that word fun keeps occurring, doesn't it? There's nothing wrong with having fun, providing it's done intelligently, within the rules and regulations.

Kevin quickly gained his microlight pilot's certificate and cross-country endorsement, and then one day confessed his great dream - he wanted to fly trikes off water. Here is a man who takes his FUN seriously!

Kevin purchased a pair of Full Lotus Floats and set about mounting these on the trike. For the uninitiated, Full Lotus Floats are catamaran-type planing hulls, but inflatable like a rubber ducky, and with the bottom surface having an attached hard polyethylene skin to provide abrasion resistance.

There doesn't seem to be a great deal of printed information available about flying microlight floatplanes, so Kevin wisely enlisted the help of a co-conspirator. You've guessed it - his instructor.

Being "old" pilots, neither of us wanted to join the short-lived "bold" contingent, so we decided taxi trials (without the wing attached) were the first step. Personally, I was concerned that the craft might be unstable, so we taxied slowly, then more quickly, then upwind, crosswind, downwind, with and without waves, each taking a turn at the "helm" while the other filmed from the shore.

I need not have worried , the Full Lotus Floats with the trike base attached proved exceptionally stable, both in the fore and aft sense, and also side to side. In fact, they didn't feel "tippy" at all, and it was obvious that they had tremendous stability and buoyancy.

Taxi trials did show up one weakness, however, we didn't have enough steerage, and in a crosswind it became difficult to turn without crabbing the bow of the floats sideways. Obviously modifications to the water rudders were in order. Here I should explain that the water rudders, at the stern, are linked to the nose wheel steering of the trike base, so just as the pilot steers with his feet when on the ground, the foot pedals have the same function on the water.

The modifications Kevin came up with was an ingenious front rudder, directly under the trike front forks, which works directly in conjunction with the rear rudders, in the same way as four-wheel steering on some Honda cars. This showed much improved steerage in subsequent trials.

Having become familiar with the equipment, it was time for the main event. Lake Illawarra, which is almost right next to the airport proved ideal for this, and a sunny light wind day was all the encouragement we needed.

With the microlight floatplane now fully rigged, we did a few more taxi trials - I was still a little concerned that the high centre of gravity that trikes have might cause a capsize, and I'm not a good swimmer, even with a life jacket (which was worn at all times). No worries, still the great all round stability of the catamaran-type hulls, and no "tippy" tendency, probably because the wing is able to tilt about the hang bracket when taxying over waves.

Here it should be mentioned that there are two modes of taxying. The slow or "plough" taxi is where the floats sit low in the water and a fair bit of water splashes around at less than 5-8 knots. Faster than that and we go into the medium to fast taxi - the hulls climb up "onto the step", the craft begins planing and the speed and manoeuvrability really pick up.

Having sufficiently explored all the taxi parameters, some mug had to be found to go all the way, and no prizes for guessing who drew the short straw! The first long run was aborted when I felt I was getting slightly out-of-wind (i.e. going sideways), but after that - a long-ish run - planing at high speed (watched by a rather envious jet-skier!) - and the floatplane just stepped off the water and flew. I flew over the Lake, getting used to the slightly different handling (all floats carry a weight and drag penalty), and then decided on a long final powered approach, directly along the wind streaks on the surface of the water. As you near the surface, the ground effect increases enormously, and you can maintain altitude (about 1 foot AMSL!) with a fair reduction of normal "cruise" power, almost indefinitely. Finally, reducing power to idle, the floats touch down and plane briefly before sinking into the "plough" mode, and excess speed decays rapidly (a bit like driving a 4WD into deep mud!)

Next it was time for Kevin to fly the machine, and after a perfect take off, he too flew gracefully over the lake, and while flying encountered a friendly passing helicopter who contacted us on the VHF radio and asked if he could fly alongside in formation and take a few pictures, as he had never seen a microlight floatplane before. We requested him to stay on the downwind side, and slightly lower, so we wouldn't get any rotor downwash, and this was accomplished without problem. (Really useful, these VHF airband radios). After the usual professional landing from Kevin (he could see the pelicans were watching critically), we compared notes and had a couple of celebratory lemonades.

Where do we go from here? Well, there is still a bit of fine-tuning to be done, Kevin is still not quite satisfied with the water rudders, and further improvements are on the way. Also we need to finely adjust the angle of dangle of the floats. At the moment, they hang slightly too nose-high in the air, and it seems likely a more horizontal hang position will be beneficial in reducing drag and increasing performance. How much fun is it? About as much as you can have with your clothes on!!

(Since this article was written, ongoing development has resulted in a couple of different manufacturers producing float-trikes, notably the Ramphos from Italy and the Canadian Krucker. That said extreme caution is advised when operating a narrow undercarriage-track aircraft such as a trike on floats...if they begin to rock from side-to-side, they usually tip right over and sink! Even though the airport at Albion Park is only a few hundred yards away from a large lake, there are no amphibious trikes operating here, and the only amphibious aircraft based at Albion Park, the HARS Catalina, would probably sink if it tried to land on the lake!)