Dave, with great respect for your work, I try to argue on what I have seen, readed from other designers.
The engine is anybody's guess. One idea that we have previously discussed is the installation of two smaller engines for reliability.
>>>> as a great part of the final weight the engine IS a critical choice, my personnal opinion would be to start from a given engine. and build around, I Know my view is not good but it hasn't been tried.
>>>> twin certified turbines fitted by a good manufacturer are a factor of reliability, but small engines fitted by "amateurs" (sorry it is not an insult, I just miss the right english word) can a be a factor of failure as you have to r&d and fit extra non-standard devices.
The fuselage, IMHO, must be carbon composite construction, with imbedded Kevlar in the shell around the occupants. The strength of carbon composite is far superior to metal construction because the plies can be laid up to suit the structural loads. The price of carbon cloth is continually coming down.
>>>> so does epoxy resins, much much cheaper and easy to use. Btw carbon may be too stiff for certain usages. Why Kevlar ?the role of a crash-proof structure is to absorb shocks, so, to break and crumple, not to resist, it has been very welle understood in the automotive industry with coltrolled-folding bodies.
chasing high end technologies is IMHO not a way to lower costs.
means that all of the other components can now be 10% weaker and thereby 10% lighter.
>>>> wow.. whitch componants ?
>>>> rotor : why not a 2 bladed semi-rigid one ?
Take the Robinson's 3-hinge teetering rotor. Add a simple linkage so the coning hinges cone in unison.
>>>> i thought the efficiency was linked to a low coning ?
a symetrical coning means less lift on the retreating blade, and , from my poor understanding, this is not the goal of a teetering rotor.
while not increasing the 2-P vibration during forward flight.
>>>> the 2/rev shake has been successfully smoothed on gyros by adding 2 simple springs on the teeter rod ends.
Why don't you consider buying (for example) the dragonfly blades and grips and fit them on a semiriigid 3 bladed hub ?
What about the blades ? The hub is fine, right, but you could have an iron-stiff hub is the blades and their links were well thought, no ?
Bash me like the arrogant newbie I am (oh yes ! hurt me
) , but leave arguments, i will keep them for my personnal use.
cheers