This post has been prompted by my interest in the helicopter concepts that Dave Jackson has put forwards:
http://synchrolite.com/SynchroLite.html
http://synchrolite.com/UniCopter.html
I first came across these ideas on the Eng-Tips forum, and freely admit to not immediately being convinced. Since then i have debated with Dave, and (not being content) have also read up a number of books on aerodynamics and helicopter design (Including Prouty). Allow me to put in my own words the advantages i perceive with the intermeshing concept (in particular Unicopter):
1. Both rotor downwashes will feed nicely into wake contraction, whereas single rotors suffer tip flow distorsion.
2. Symmetry of main rotors will allow reduced pilot workload/training.
3. Careful design could lead to commonised parts between LH and RH rotors.
4. Removal of tail rotor will reduce power requirement by at least 10% (includinh high speed stabiliser trim drag) - downwash rotation wastes at most 2%.
5. By ultimately designing a rigid rotor, retreating blade may be unloaded. This avoids tip stall drag and reverse flow region. Outboard advancing, may allow optimum blade AOA in all conditions.
6. By ensuring that effective wingspan is always across both rotors at high speeds (conventionals end up lifting in front and rear quadrants), more efficient cruise may be obtained.
7. Twin pusher props will allow efficient cruise, as well as effective yaw control in reduced g manouvres.
OK, this is a very brief summary of the conclusions i have come to. I thought to start this thread to pick the minds of the best helicopter experts out there - the guys that fly 'em. To some extent i will sit back, and see what points come out of this thread.
Thanks in advance for your thoughts.
Mart