Since 2005 the most popular propulsion system by far for two-seat Challengers is the 65 hp Rotax 582 engine with a 2.6-to-1 reduction drive and 60 inch diameter three-blade propellor. The standard engine for the two-seater is actually the 40 hp Rotax 447 and the most common engine is the 50 hp Rotax 503. However, since the availability of the 582 virtually all Canadians have selected it for substantially greater horsepower, lower fuel consumption and higher reliability. The choice is obvious!

The additional thrust generated by this combination of engine, re-drive and prop converts directly into stronger takeoff, climb and cruise speed. New Challengers loaf when flying in formation with older ones and if they choose can simply move the throttle forward and leave their compatriots in the dust.

The 582 gives scintillating performance on the Challenger. Many people say that the 582 plane on floats performs like the floats aren't there and that the 582 flies with a passenger like a 503 flies solo! For more info on the 582 as well as videos showing 582 and 503 Challengers performing side by side click here. For pricing details and package configurations click here.

Rotax 503 & 582 Engines

The current Rotax 582 and 503 engines were developed expressly for use in aircraft, based on substantial real world experience with their predecessors.

Numerous improvements have been incorporated, starting deep inside with a heavy duty crankshaft and redesigned bearings. On the outside, a new dual ball joint exhaust system isolates the muffler from vibration and improves engine breathing. Other changes are less visible but no less important.

Dual independent electronic ignition systems provide redundancy and eliminate the need for timing adjustments. Two spark plugs per cylinder also contribute to redundancy and yield a more efficient fuel burn. Plug fouling is no longer an operational concern. Twin carbs provide the correct fuel-air mixture to each cylinder. Taken all together, this significantly increases power and lowers fuel consumption, benefiting performance, range and endurance.

The new Rotax 582 Mod 99, known as the Blue Head, has replaced the older Mod 90, known as the Gray Head. The Blue Head has a number of important design changes which lead to significant improvements in reliability over the Gray Head. Two of these changes in particular yield major benefits.

A new ceramic water pump seal replaces the previous rubber seal and is backed up by an oil seal on the reservoir side thus eliminating the problem of leaking cross shaft seals. This together with the new dexcool long life coolant designed for aluminum block engines has eliminated cross shaft replacements.

A new bypass circuit recirculates coolant through the engine until it reaches operating temperature. The new thermostat then opens gradually rather than abruptly to circulate coolant to and from the radiator. The by-pass circuit and new thermostat together adress the shock cooling and cold seizures which occasionally occured on the Gray Head.

The time between inspections on the new 582 and 503 is 300 hours, versus 150 hours for the older versions. Most people maintain the engines "on condition", with no predetermined time between overhaul (TBO). This gives much lower cost per hour figures than engines with much higher TBO's since they have dramatically higher overhaul costs.

These engines with their high power-to-weight ratios provide plenty of power for the light weight Challenger with its large wing. By comparison, the much heavier liquid-cooled Rotax 912 engine, required by aircraft similar to the Challenger but which weigh more and have smaller wings, costs $20,000!
The 582 and 503 cost a third less to operate and, over the 1,200 hour TBO
of the 912, the 582/503 overhaul expenses will be half as much per hour.

And unlike the 912 and other oil sump engines found in general aviation aircraft, the 582 and 503 require no inconvenient and time-consuming preheating, even in Canada's nastiest winters! Just turn the key and go!

2.6-to-1 Reduction Drive

The Challenger uses a cog belt reduction drive instead of a gearbox, even though the manufacturing cost is higher. This more elegant approach is lighter, less complex, and more reliable. The re-drive elevates the prop higher than a gearbox, thereby allowing the engine to be mounted behind the fuselage out of the slipstream, instead of up on the wing creating drag.

The cog belt dampens vibration and provides the positive engagement of a gearbox without the attendant backlash concerns. Unlike a gearbox, the cog belt uses no oil bath, so it requires no preheating - no matter how frigid the air.

60 Inch Prop

The new 2.6-to-1 reduction drive is taller, providing clearance for a longer 60" propeller. The new prop turns at 2,200 rpm in cruise which is much more efficient than the 2,600 rpm rate of its predecessors. Decibels are down and the lower pitched sound is quite pleasing. Older Challengers have a 2.2-to-1 re-drive with a 54" prop or a 2.1-to-1 drive with a 52" prop.

The Challenger II 582 Power Packcomes with a 60 inch 3-blade prop from Warp Drive Inc. This is a ground adjustable unit with carbon fibre blades and nickel leading edge protection.

With the 503 the preferred prop is a 2-blade fixed pitch wooden prop which is the lightest and cheapest choice. A hard epoxy insert provides leading edge protection to prevent erosion from spray, slush and rain.