Aussie_Paul
A reforming stirrer!!!!!
- Joined
- Oct 30, 2003
- Messages
- 4,441
- Location
- Ballarat Australia
- Aircraft
- None at the moment.
- Total Flight Time
- Since 1982 Gyro 5000+ mostly instructing, and approx. 200 fixed wing in the late 1960s.
We have been having some great discussions on Norm’s forum, re calculation of the CoM or VCoG.<br><br>As an older but not so bolder gyro pilot, I have a test that I perform to see how far out the thrust line and VCoM are. This is certainly not for someone who has not been flying for a lot of years and fully understands the CLT principles.<br><br>I take a machine out for a test flight and fly it at the trim speed, and if needed I adjust the trim speed until it is representative of the particular gyro type, lets say 50 mph. At this point I prefer the machine not to be stab equipped.<br><br>I let the stick go and slowly add full power. If the nose goes down and the machine increases speed, then the thrust line is above the VCoG. If the nose goes up and speed decreases then the thrust line is below the VCoG.<br><br>If the nose goes up slightly, the speed remains constant, and the aircraft climbs then we are talking CLT.<br><br>I then add the h/stab and set it so the response is still the same. The h/stab will then help to iron out the up and down bumps nicely. Also the faster the machine goes the more the parasitic drag of the everything hanging below the thrust line will be forcing the nose down. As this happens the h/stab begins to have a negative AoA and so opposes the nose down pitching moment of the parasitic drag.<br><br>The problem with this system is that you have to have a lot of experience to perform these tests safely. As the developer of Firebird, I am fortunate to have gained this experience over the years in sorting out the Raf stability problems, both pitch and yaw.<br><br>So far my experience has been proven by the CoM pic method. This expertise did not happen over night, but is the fruit of slowly working through these items with the help of Chuck B and others.<br><br>I hope that this report makes sense and is beneficial to others.<br><br>Aussie Paul.<br>