Most 600-class models sport a 50-size engine making 1.9
horsepower and costing $200-ish. Larger .55-size engines are available but
they're also more costly (in the $300-400 range). The .55 makes 2.1 horsepower
and it's in great demand with folks flying 3D because the extra
horsepower makes maneuvers easier (easier to cover up mistakes too). The extra
power is - quite frankly - corrupting because you never want to go
back.
However, while swapping in a pricey OS55 or YS60 for the OS50 Hyper is the
only choice for me-too Oriental helis, our approach is different.
Old school hotrodders know there's no substitute for cubic inches so
we figure, why play around? When it comes to horsepower, if some is good, more
is better . . . enter the 91-conversion. Instead of a paltry 1.9 to 2.1
horsepower boost, we're cranking things up to 3.4 ponies. Can you say
yee-haw?
Of course, the 91-class engine weighs a bit more but you make up for that by
using 620 mm rotor blades, whihc means the disk loading goes from 8.09
oz/ft² to 8.15 oz/ft² (a nearly an insignificant change). The
power-loading (pound/horsepower), however, goes off the chart. The math is
simple. With a 55 there are 3.625 pounds/horsepower while the 91 means
only 2.4 pounds/horsepower . . . that's big league!
However, the most amazing aspect of a big-block Pantera is how docile and
well-mannered it remains (and cheap to crash), which is important unless your
money grows on trees. It flies better and best of all, you don't have to be
an expert pilot to enjoy the rush!
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