I recently acquired an electric-powered seaplane called the Aventura II.  I had actually flown the model before at DAC and, quite frankly, it was a PIG to fly. In any case, when it came up for sale, I could not resist, as it is such a funky looking aircraft! The fibreglass fuselage/hull is well made and quite light. The wings and tail surfaces are built-up balsa construction and come pre-covered in transparent film.

After fitting the Aventura with radio control gear we set off for a nearby lake. With a slight breeze, I began to taxi my new acquisition downwind. It was very difficult to steer, as the wind caused it to weather-vane. Also, the wings kept tilting to one side or the other. Another problem was the nose kept submarining. However, with full throttle and full up elevator, she was finally planing, ready for take-off. This tactic was not wise, however, as just after lift-off, the sudden wing drop indicated a stalled wing. A few wobbles later, after nearly crashing into the water, it was a safe height above the water. Phew! Mental note… don't be holding full elevator at take-off; only use it to get the aircraft planing on the water.

I proceeded to fly a few circuits, with the Aventura displaying similar bad habits as it had shown at DAC - dutch rolling and generally horrible to fly. Meanwhile, my colleague was calling out manoeuvres for me to try! "Loop. Roll. Touch-and-go." I managed to land safely, with knees shaking, wondering why I bought a "lemon". I decided to modify the Aventura to try and improve its taxiing and flight performance.

To aid taxiing, the pontoons beneath each wing were extended and made adjustable for fine tuning. I gave the front of the hull a "nose-job" to prevent submarining. I also added a water rudder to aid steering and prevent weather-vaning. Subsequent taxiing has been much easier. Upon inspection of the wing, I noticed one side had wash-out and the other wash-in! The tailplane was also warped. Not a good combination. After eliminating these problems, I built a new battery support higher up, just behind the windscreen, with the aim of reducing the pendulum effect which I thought may be responsible for the dutch-rolling.

On a couple of heavy landings, the pontoons had rotated sideways, as they are only held in place with elastic bands. This caused one wing to tilt over into the water. In this situation, applying power simply made the aircraft do donuts due to the drag of the wing. Not fancying swimming out in the freezing water, we waited about ½ an hour for the wind to blow it to shore. To overcome this problem, the top of the pontoon legs have been modified with some lateral bracing. One flight I tried having the pontoons close to the hull, to see if this would stop zig-zagging on take-off. The problem with this, however, was that the pontoon volume was not sufficient to stop the seaplane tilting over, ie the righting moment due to the buoyancy of the pontoons was not large enough to overcome the statically roll-unstable nature of the mono-hull seaplane.

A few other mods include: changing the propellor from Master Airscrew 7×4 to Graupner Slim 8×4, and soldering the motor brush wires to the endbell (they were supplied with the wire only held by the brush springs). Flight characteristics are now quite good.

The power system of 7×CP1300 nicads and Permax 450 motor and 8×4 prop is more than adequate. The Aventura II is planing in a couple of meters, and takes off in about 10m. It maintains level flight on ½ throttle, and is capable of doing loops, rolls, stall turns etc. Inverted flight is almost impossible with such a low centre of mass and washout in the wings, but this aircraft is not really designed for inverted flying. Touch-and-go's are good fun, and landings are always a crowd-pleaser. There is something very majestic about a seaplane landing.

Specs:

• Total Weight = 1050g (incl. 260g battery pack)

• Wingspan = 1.1m

• Motor = Permax 450

• Prop = Graupner 8×4

• Slim Batteries = 7×CP1300 nicads

A few weeks ago, if someone asked whether they should buy an Aventura II, I would have said "don't waste your money". Now, I would not hesitate to recommend it. Seaplanes are a little more challenging than flying off land, but once you overcome the fear of your electrics becoming submerged and frying, it is actually great fun.

Happy flying (not frying!)

Jon Pape