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TURBO CHARGERS AND EZ'S(From CP35, Page 9, January, 1983)
This subject is starting to
come up more and more lately. Review - first, RAF does not recommend a turbo charger
on a VariEze or a Long-EZ. These aircraft, when operated within the normal envelope
and at normal gross weights are probably the last aircraft to need a turbo charger.
They are excellent high altitude airplanes having the capability to climb well over
25,000 feet. Turbo chargers and their associated parts are heavy, 20 to 25 lbs for
an average installation. This is right on the tail, absolutely the worst possible
place to add weight.
A turbo charger installation without a constant speed prop is
self defeating. If you keep your standard prop, your engine will over rev at
altitude. If you install a larger prop to take advantage of the additional
horsepower available at altitude, your engine will not be able to turn up enough RPM
static, and you will have marginal, possibly even dangerous take off performance.
Remember your turbo will not help at lower altitudes. (unless you overboost
a certain way to destroy your engine).
For acceptable take-off performance, you must be able to turn at
least 2400 RPM static, (2500+ PRM Is better). Constant speed props are not
recommended at all. Weight, complexity, initial expense, maintenance cost, and
unreliability while running in the wake of the wing/ center-section are excellent reasons
not to fool with these props. Use good judgement - the simple, lightweight, wooden, fixed
pitch props have a good history and with care and attention to checking bolt torque at
required intervals, can give long, reliable service.