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Old January 25th 04, 04:51 PM
Kathryn & Stuart Fields
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I suggest you contact B.J. regarding that cable head. I heard him tell one
guy not to fly the cable head. Also the pitch bearings in the Safari are
nearly identical to the R-22 and even with grease did not experience failure
during the first 75 hrs. I flew mine. I have converted the grips to oil and
am using ATF which, I'm led to believe, is the same as the R-22.
Some of the posters believe that only certified ships are safe. At the
present time there has been only one fatality in the Safari and that was not
attributed to the aircraft in any way. I'm sure that Robinson wishes he
could say that R-22. BTW there are more than one Safari with over 1,000
hrs. accumulated.
I previously owned a couple of Scorpions and did not get either into the
air. I sold them to a guy who had an A&P working on them and I don't think
they ever got them in an unchained hover. The last time I saw them try, the
tail rotor drive belts were slipping and he couldn't stop the ship from
trying to rotate. Only the chains stopped him. The other noticeable thing
was the noise. The exhaust noise on the evinrude was painful some distance
away. I don't know a good way to avoid hearing damage even with plugs and a
headset.
Stu Fields
wrote in message
...

The R22 is a fine helicopter. However, there are those that fly jet
rangers that would call the R22 a "Death Trap". You suggested that
the Scorpion is not safe. However, you did not specify 'why' you
don't consider it safe.

I don't mean to sound argumentative, but I need cold, hard facts and
not general rumors that the ship is dangerous. What is specifically
bad about the Scorpion? I realize that there are many unorthodox
things being done, but is that really bad?

Take the cable-in-shaft control head for example. The entire rotor
head tilts on a U-Joint rather than cyclicly changining the pitch as
does a traditional helicopter. You might look at that and wonder why
BJ Shramm did it that way.

Here is the answer. At the time, the patent on elastomeric bearings
was still in effect. BJ could not use them. He elected to use
traditional thrust roller bearings. The problem with using these
bearings is that if they are under a load and are used cyclicly
(rocking back and forth with every revolution), the grease rolls out
of the way after a few minutes of operation and the bearings have to
operate without lubrication. This results in a failure.

To avoid this problem, BJ tilted the entire rotor head rather than
changing the pitch cyclicly. In fact, the pitch on the blades only
changes when the collective is moved and not the cyclic. This results
in the grease being retained for a longer period of time. It still
needs frequent regreasing, but at least you don't need a new set of
bearings after each hour of flight.

But getting back to the main point, I really do want to hear about
specific problems with the Scorpion. I want to correct these problems
as much as possible.

Dennis H.

(Ryan Ferguson) wrote:

Man. Your messages about flight training and your experimental
helicopter just give me cold chills. I'd have to agree with the
others who've suggested that you give this another thought. Do you
have kids? A family? It's not worth it, guy.

Side note. Forget the Scorpion for meeting solo requirements. (You
do realize you need an endorsement for that specific helicopter,
right?) No sane instructor would sign you off to solo that thing.
Lord have mercy.


Dennis Hawkins
n4mwd AT amsat DOT org (humans know what to do)

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