Hartzell can’t make carbon fiber blades inexpensively, others can.
Stainless steel leading edge protection is the crude way that MT did it for years, mechanically formed. I have them and clean the rust off after every flight. Electro-formed nickel is better. The tooling for the nickel part and the composite blade are produced using matching CNC data.
Yes, uncertified ones :-)
MT switched to electro-chemically formed nickel leading edges a long time ago.
They offer both leading eadges or the 4-blade, stainless steel or nickel. At least that was the case in 2015. I took nickel, because they recommended it.
Alexis wrote:
Wood is the perfect natural high tech material for a propeller.
Well, in my opinion, wood is the perfect a very good material for the whole airplane. And if smartly reinforced by autoclave cured carbon elements, wooden structures can be remarkably strong and light. An example I’m familiar with is a single sitter MC-30 Luciole. Empty weight ca. 95kg. wing spar is composed of 3 different kinds of wood and pre-formed carbon elements. It’s been tested! to withstand loads of 9g
Another good example of carbon reinforced wooden structure is spar of rudder of the same aircraft:
External coating serves mainly to protect the structure from environmental factors, mainly water, but in case of a prop also mechanical damages. The reason why multiple layers of fabric (fibreglass or carbon) are applied is because a single layer isn’t necessarily water proof. MT would not be alone in marketing their external coating to play a structural role. Bellanca did the same in case of 14-19-3 and Vikings.
Wood’s greatest strength is it’s price. The material literally grows on trees and can be processed with very simple tools.
This is an example of a professionally made prop for Rotax 912. 4 different kinds of wood. Costs about 250 Euro.
wood: € 250
bio-composite: € 2500
Alexis wrote:
Certified light GA is for better or worse slipping into irrelevance.
That’s a bold statement and cannot be supported with facts. The number of GA airplanes is constant, here and in the USA well.
At the risk of thread drift… there are approximately 550 new Vans RV aircraft each year alone. All the certified GA manufacturers put together only shipped 890 single engine aircraft in 2016. It’s difficult to find hard figures for how many non-certified singles are being flown every year (apart from Vans), but as a proxy, Rotax ship more aircraft engines than Lycoming and Continental put together (and some of those Lycoming and Continentals are going on non-certified). If GA airplanes is constant, then the proportion of certified is declining because it’s pretty much certain that there are more piston non-certifieds having their first flight this year than certified aircraft.
The beautiful Bellanca Viking, in addition to the Robin, is another advertisement for wooden load bearing structures.
At the risk of thread drift… there are approximately 550 new Vans RV aircraft each year alone. All the certified GA manufacturers put together only shipped 890 single engine aircraft in 2016.
The fact (which I like) that the Experimental scene is so active and growing does not necessarily mean that certified GA is dying. Actually it has been pretty constant for the last 20 year and even recovered a bit. As long as you cannot legally fly IFR with an Experimental in Europe there will always be a market for certified airplanes. And there’s another issue: Not everybody is into building airplanes. I for one prefer flying them and I am not in a phase of my life where I would spend 5 years to build an airplane.
