To: WhoNeedsRunways
You have just proved my main point regarding the design of the rotor head and you have proved an unstated point about how Robinson relates to their operators.
In my report I state that the pitch links on the Robinson helicopters lead the blades by approximately 72 degrees and that when you want to fly forward you have to offset the cyclic by approximately 18 degrees to the right. The opposite would be true if you wanted to fly backwards only this time you would offset the cyclic approximately 18 degrees to the left. In your statement you indicated that Tim Tucker in his testing for recovery from Zero G would pull the cyclic straight back with a TAD of left cyclic. How much is a tad relative to the degrees in the compass? Could it be approximately 18 degrees? In his testing, he undoubtedly found that to pull straight back on the cyclic would introduce a right roll component, which the POH tells you to avoid at any cost.
Here is the unstated point. If Tim Tucker did discover this fact then, why-oh-
why didn’t he provide this instruction to the operators of Robinson Helicopters? The instructions in the un numbered last page of section 4 of the POH were in fact created to cover the collective asses of the FAA and Robinson. If it is proved that a pilot violated these instructions then it could be easily proved in court that it was pilot error. If the pilot follows the instructions for recovery from Zero G he can exacerbate the right roll created by the high mounted tail rotor and in the process kill himself. Robinson in my opinion will not include in the instructions to apply a tad left cyclic because they would have to explain why which would lead to them telling you and the others that they have a design problem in their rotorhead.
If you or anyone reading this post are attending the Tim Tucker training program please ask him about the points I have raised in this forum. Remember one thing, this man is a pilot and not a God and he represents the thinking of Robinson Helicopters. You as Pilots and mechanics have every right in this world to challenge him. If one of you is planning on attending and you don’t have a copy of the report please send me an email and I will send it to you. Also include your fax number and I will send a diagram that fully explains the problems with the Robinson rotorhead. If you request both and there is more than one request I will send the report to all but the faxed diagram will go to the first person requesting it.
Regarding the differences between theory and practice, the THEORY regarding gyroscopic precession and its’ relationship with rotor head design is not theory but has been reduced to engineering practice ever since the VS 300 took flight. In two blade rotor systems like Bell the pitch link leads the blade by 90 degrees. On some other helicopters the swash plate command leads the desired reaction by 45 degrees and the pitch link leads by 45 degrees which totals 90 degrees which is the phase angle of the blades. On the Robinson the blade phase angle is 90 degrees but the pitch link leads the blades by approximately 72 degrees and, the swash plate movement leads by 90 degrees which requires the pilot to adjust his cyclic by just a tad to compensate for the 18 degree difference.
To: Outside Loop:
First of all I have already had a request for the report by a member of ATSB. The ATSB like the NTSB in the States can do little even if they know a design to be defective. They can only wait for an accident to occur. The NTSB has had the report since 1996 and they could do little. However, last month there was an accident involving a highly experienced pilot with a lot of hours in a lot of helicopters including. flying in a Robinson Aerobatics team and conducting flight instruction in an R22. This man lost his main rotor while conducting flight instruction with a zero hour pilot. It is not known who was flying. In any case, the NTSB was instructed by the Chairman of the NTSB to reopen the investigation as a result of the accident, which occurred in California.
Regarding how the Robinson helicopters are employed in Australia I have seen examples on Canadian and US television. In every case, I hold my breath waiting for the helicopter to come falling out of the sky. It appears that you and your comrades are violating every instruction in the POH that restricts you from flying under the stated conditions. When something happens as a result of your collective actions Robinson can easily claim that it was pilot error even though the accident would have been caused by the design of the rotorhead.
According to NTSB records there were two R22 rotor loss accidents in New Zealand and two R22 rotor loss accidents in Australia. The report did not address the R44. I would assume that the causes for the accidents were listed as pilot error. For sure, Robinson would not state that the design of the rotorhead and the confusing rigging procedure were a contributing factor.
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The Cat