Lu Zuckerman
30th Dec 2000, 22:23
To: LAMEs and A&Ps that work on Robinson Helicopters
In making this post I will make several assumptions;
1) In order to be able to work on the Robinson Helicopters you attended a factory school or, you attended a Robinson sponsored school that was operated by a Robinson distributor.
2) You were taught flight theory as well as how to rig the helicopter.
3) If you were taught in the USA you were told about gyroscopic precession and if you were taught in the UK or OZ you learned it in a different way. (Unless the subject was taught by a Robinson representative).
Although there are variants of the above assumptions it can be assumed that they are correct. If that were the case, I would like to pose these questions.
1) In learning about gyroscopic precession or the same phenomenon as taught in the UK or Oz did they use the Robinson system as a demonstration or, did they use a Bell system as a means of explaining the subject?
The reason I ask this is because there are at least two websites that are the home pages of two Robinson dealers and flight schools. These websites have a very good explanation of how a helicopter flies. They have excellent pictures of Robinson helicopters and the major elements of those helicopters. They show pictures of Bell and Robinson rotorheads and they then go into the subject of gyroscopic precession.
Although the preceding text on the website(s) dealt with a Robinson rotorhead they explained gyroscopic precession by using a Bell system as an example. The two systems are different.
2) In teaching the rigging process how did they explain the differences in the positioning of the Robinson blades as opposed to those of a Bell helicopter and, how did they rectify what they taught about gyroscopic precession as related to the positioning of the blades?
I assume they taught that the precession phase angle was 90 degrees and yet the Robinson blades are disposed 18-degrees from the respective axes during the rigging process. What did they tell you about where the blade disc would dip if the cyclic was pushed forward from the rigged neutral position?
To get a better understanding of what I am asking, log onto the following websites and download the diagrams.
http://205467.homestead.com/diagrams.html
http://pprune.homestead.com/files/rigging.jpg
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The Cat
In making this post I will make several assumptions;
1) In order to be able to work on the Robinson Helicopters you attended a factory school or, you attended a Robinson sponsored school that was operated by a Robinson distributor.
2) You were taught flight theory as well as how to rig the helicopter.
3) If you were taught in the USA you were told about gyroscopic precession and if you were taught in the UK or OZ you learned it in a different way. (Unless the subject was taught by a Robinson representative).
Although there are variants of the above assumptions it can be assumed that they are correct. If that were the case, I would like to pose these questions.
1) In learning about gyroscopic precession or the same phenomenon as taught in the UK or Oz did they use the Robinson system as a demonstration or, did they use a Bell system as a means of explaining the subject?
The reason I ask this is because there are at least two websites that are the home pages of two Robinson dealers and flight schools. These websites have a very good explanation of how a helicopter flies. They have excellent pictures of Robinson helicopters and the major elements of those helicopters. They show pictures of Bell and Robinson rotorheads and they then go into the subject of gyroscopic precession.
Although the preceding text on the website(s) dealt with a Robinson rotorhead they explained gyroscopic precession by using a Bell system as an example. The two systems are different.
2) In teaching the rigging process how did they explain the differences in the positioning of the Robinson blades as opposed to those of a Bell helicopter and, how did they rectify what they taught about gyroscopic precession as related to the positioning of the blades?
I assume they taught that the precession phase angle was 90 degrees and yet the Robinson blades are disposed 18-degrees from the respective axes during the rigging process. What did they tell you about where the blade disc would dip if the cyclic was pushed forward from the rigged neutral position?
To get a better understanding of what I am asking, log onto the following websites and download the diagrams.
http://205467.homestead.com/diagrams.html
http://pprune.homestead.com/files/rigging.jpg
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------------------
The Cat