Cyclic and Collective Update
Join Date: Nov 2004
Location: Cambridgeshire, UK
Posts: 1,334
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Shawn,
The advanced aerodynamics section could benefit from a discussion about total pressure, dynamic pressure and static pressure. There is no controversy about a rotor acting as a pump to increase average total pressure from above to below (and of course it stays the same for a given weight, although distribution across rotor depends on flight condition). This also provides a nice explanation of how Bernoulli's theorem (which explains lift) fits in with Newton's theorem (which explains downwash). It would also allow rotorheads to understand better debates about things like the pressure bubble myth (or upwash from ground plane reflected helicopter image).
In the flight controls and rotor heads section you could include an explanation about how the rotor is its own flying machine, with the pilot actually having very good control over pitch and roll rates (with pitch links correcting for aero-gyroscopic lead angles etc). But that the rotor has a servo effect on the aircraft pitch and roll rates by generating a lateral force above the fuselage CG, with the associated delay in response. This can then lead into explaining why hingless designs offer a faster manouvreing response over teetering (along with dynamic rollover, reduced g pushovers etc).
Hope this what you are after,
Mart
The advanced aerodynamics section could benefit from a discussion about total pressure, dynamic pressure and static pressure. There is no controversy about a rotor acting as a pump to increase average total pressure from above to below (and of course it stays the same for a given weight, although distribution across rotor depends on flight condition). This also provides a nice explanation of how Bernoulli's theorem (which explains lift) fits in with Newton's theorem (which explains downwash). It would also allow rotorheads to understand better debates about things like the pressure bubble myth (or upwash from ground plane reflected helicopter image).
In the flight controls and rotor heads section you could include an explanation about how the rotor is its own flying machine, with the pilot actually having very good control over pitch and roll rates (with pitch links correcting for aero-gyroscopic lead angles etc). But that the rotor has a servo effect on the aircraft pitch and roll rates by generating a lateral force above the fuselage CG, with the associated delay in response. This can then lead into explaining why hingless designs offer a faster manouvreing response over teetering (along with dynamic rollover, reduced g pushovers etc).
Hope this what you are after,
Mart
Inherent Sideslip etc
Shawn, the MH-60k has been running around with an electronic slip indicator for two decades.There were some interesting discussions with the IBM folks in getting it to function correctly.
Also, when you get around to the inherent sideslip discussion, don't miss those machines that had lateral shaft tilt built in ( CH-54 and SH-2 for instance ), and the "wonderful" effects that feature had on inherent sideslip in all of the non-hover flight conditions.
Thanks,
John Dixson
Also, when you get around to the inherent sideslip discussion, don't miss those machines that had lateral shaft tilt built in ( CH-54 and SH-2 for instance ), and the "wonderful" effects that feature had on inherent sideslip in all of the non-hover flight conditions.
Thanks,
John Dixson
