As a rule of thumb - for vehicles where the location points of the prop move - no you can't.
Top spec rally cars and supercars can use composite prop, which way next to nothing (I've seen a prop for a now defunt WRC that, excluding cruciforms, weighed 1.5kg). However, these are for cars with independent suspension. If the locations point of the prop moves (as it does with solid axles) then you have a problem in getting the prop to accomodate the change in distance bewteen the two ends. Using a CV and tripod type union at each end respectively, you can accomodate a certain amout of length change, but not significant. The only other way to do it is to fit a sliding spline type arrangement in the middle of the prop - which you ain't doing with a light weight tube.
So, the question is - what is the prop for? If it's for a track based Subaru - yes. If it's for an off-road based Landy - no. Will shaving a few ounces or kilos off the prop make all that much difference?
Philisophical point for the day for RRB. There's no such thing as 'over engineered' - only under-engineered and over-massed ;-) If it's stronger than it needs to be then it's about right - if it's stronger than it needs to be and weighs a lot more as a result - it hasn't been engineered well enough, but it has got too much metal ;-) Discuss over a beer! :lol:
Cheers
8)
Eeyore
