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Ben_Chiu Certificates/Ratings/Crew Stations: 5. "RE: Adverse yaw and roll coupling" 11-18-02, 17:43z  Greetings Dave: > The same forces that do create adverse yam likely do exist on the > rudder as well. However, the vertical stab(rudder) is not as long as the > wing, so the moment arm cannot exert the same force on the plane as the > longer moment arm wing/aileron can. If you extended the vertical fin to > a length similar to the wing, applying rudder would likely cause a pitch > up. OK, I'll buy that. (But I'd also counter that the length of the fuselage length should provide an "arm" to work with and the surface area of the rudder is comparable to that of the ailerons--at least in the aircraft that I fly day-to-day--and these factors should offset what you're saying.) > The Luscombe I got my first 14 hours on (1946 8A) has an "impressive" > amount of adverse yaw; a great tool to learn about it whereas our C150H > has very little (I like to fly the Luscombe every so often to prevent > lazy feet). Very interesting. I have a friend, Jonathan Baron (Producer of the Air Warrior series of games), flies a Luscombe and he only has one leg! > In my RC model experience, I've seen that roll coupling on the models is > tied also into the airfoil shape and dihedral of the wing. "Flat bottom" > wings tend to roll more than symetrical with rudder. My sons RC trainer > can be almost rolled with the rudder (large wingspan, clark "Y" airfoil > etc) where as my RC Extra rolls very little with rudder (symetrical > airfoil etc). Ah, yes. Very interesting! My thoughts were that airfoil shapes would make a difference (a vertical stabilizer is usually symmetrical, and they can be offset in singles to counter left-turning tendencies). > So my two cents are the forces are there, but not in an amount you can > percieve. > > Now to really muck up the discussion; I have had several RC models that > would either pitch up (or down) violently with full rudder applications. > In reseraching this, it has to do with the placement of the horizontal > stab, but that gets into another complicated subject!!!! Yes! That's what I was thinking as well. Would a T-tail have as much roll coupling? It's been a number of years since I've flown a T-tail, so I haven't been able to test this. Thanks, Dave! Ben -= VPC OffLine Reader 2.1 =- Registered to: Ben Chiu -OLR.PL v1.80- Remove | Alert Edit | Reply | Reply With Quote | Top

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Subject      Author      Message Date     ID      Adverse yaw and roll coupling    Ben_Chiu       11-16-02              RE: Adverse yaw and roll coupling    Tarmack       11-18-02       1            RE: Adverse yaw and roll coupling    Ben_Chiu       11-18-02       4                 RE: Adverse yaw and roll coupling    djpacro       11-19-02       9                      RE: Adverse yaw and roll coupling    Ben_Chiu       11-19-02       14                 RE: Adverse yaw and roll coupling    Mike_Greenwood       11-19-02       10                      RE: Adverse yaw and roll coupling    DHamblin       11-19-02       12                      RE: Adverse yaw and roll coupling    DHamblin       11-19-02       13                           RE: Adverse yaw and roll coupling    Ben_Chiu       11-19-02       16                      RE: Adverse yaw and roll coupling    Ben_Chiu       11-19-02       15                           RE: Adverse yaw and roll coupling    djpacro       11-25-02       21                                RE: Adverse yaw and roll coupling    Ben_Chiu       11-25-02       22         RE: Adverse yaw and roll coupling    DHamblin       11-18-02       2            RE: Adverse yaw and roll coupling    Ben_Chiu       11-18-02       5                 RE: Adverse yaw and roll coupling    DHamblin       11-18-02       7                      RE: Adverse yaw and roll coupling    Mike_Greenwood       11-19-02       11                           RE: Adverse yaw and roll coupling    AlanParkinson       11-22-02       19                                RE: Adverse yaw and roll coupling    Mike_Greenwood       11-23-02       20                      RE: Adverse yaw and roll coupling    Ben_Chiu       11-19-02       17         RE: Adverse yaw and roll coupling    IFLYExtra300S       11-18-02       3            RE: Adverse yaw and roll coupling    Ben_Chiu       11-18-02       6                 RE: Adverse yaw and roll coupling    Tarmack       11-18-02       8                      RE: Adverse yaw and roll coupling    Ben_Chiu       11-19-02       18                 RE: Adverse yaw and roll coupling    ghmorris       12-01-02       23                      RE: Adverse yaw and roll coupling    ghmorris       12-01-02       24                      RE: Adverse yaw and roll coupling    Ben_Chiu       12-01-02       25                           RE: Adverse yaw and roll coupling    ghmorris       12-02-02       26                                RE: Adverse yaw and roll coupling    Ben_Chiu       12-02-02       27                                     RE: Adverse yaw and roll coupling    ghmorris       12-02-02       28

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