SOLO flight rules

Hi Cam...
You are absolutely correct. In the case of that particular Enstrom, the
engine lost power and the clutch didn't disengage. So, the airflow upward
through the rotor which should have been retaining the rotor's autorotation
R.P.M..was expended trying to turn the engine due to the NOT disengaged
clutch. The situation was bad anyway because they didn't have much
altitude- maybe a couple of hunderd feet.

Cheers Bob, Presuming they use a sprag type clutch, I'd imagine it would
have to be very badly worn to lock up in the driving state. Of the different
types (sprag) I've seen, they seem inherently bullet proof buy there design.
I'd love to see a fataly damaged one just to see how they wear.

Cam.....

On most helicopters that I have been in, testing the split (sprag
clutch) is part of the power on preflight. It seems kind of odd that
such a catastophic clutch failure would occur without warning in the
preflight. Perhaps they skipped that step.

Dennis H.

"Cam" wrote:

Cheers Bob, Presuming they use a sprag type clutch, I'd imagine it would
have to be very badly worn to lock up in the driving state. Of the different
types (sprag) I've seen, they seem inherently bullet proof buy there design.
I'd love to see a fataly damaged one just to see how they wear.

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

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."

To find out what an H-1B is and how Congress is using
them to put Americans out of work, visit the following
web site and click on the "Exporting America" CNN news
video: http://zazona.com/ShameH1B/MediaClips.htm

"Sprag clutch" might have been more understandable. Presumably we are
talking about a simultaneous sprag and engine failure. A locked sprag
alone won't down a helicopter.

The scorpion's main clutch engagement is mechanical rather than
electrical. Should the sprag and engine fail simultaneously, the main
engine clutch can be disengaged in less than one second. I don't know
if this would be soon enough, but the 2 minutes that electric clutches
take is most likely too long.

Getting back to the scorpion. It would seem that nobody here has any
concrete facts regarding any serious safety flaws other than the short
landing gear. We (I) have discussed several items that could be
designed better, but nothing was a serious safety issue. The older
scorpion design is apparently high maintenance, but still safe.

Dennis H.


"Bob" wrote:

When a "clutch" (freewheeling unit) locks up, your rotor stops turning.

Bob



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

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."

To find out what an H-1B is and how Congress is using
them to put Americans out of work, visit the following
web site and click on the "Exporting America" CNN news
video: http://zazona.com/ShameH1B/MediaClips.htm

Not true in many (most) turbines.

Bart

wrote:
On most helicopters that I have been in, testing the split (sprag
clutch) is part of the power on preflight. It seems kind of odd that
such a catastophic clutch failure would occur without warning in the
preflight. Perhaps they skipped that step.

Dennis H.

"Cam" wrote:


Cheers Bob, Presuming they use a sprag type clutch, I'd imagine it would
have to be very badly worn to lock up in the driving state. Of the different
types (sprag) I've seen, they seem inherently bullet proof buy there design.
I'd love to see a fataly damaged one just to see how they wear.


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

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."

To find out what an H-1B is and how Congress is using
them to put Americans out of work, visit the following
web site and click on the "Exporting America" CNN news
video: http://zazona.com/ShameH1B/MediaClips.htm

"Cam" wrote in message
...
Cheers Bob, Presuming they use a sprag type clutch, I'd imagine it
would
have to be very badly worn to lock up in the driving state. Of the
different
types (sprag) I've seen, they seem inherently bullet proof buy there
design.
I'd love to see a fataly damaged one just to see how they wear.

Cam.....

I did a little research and found the NTSB report. Docket number NYC87MA024.
It says the sprag clutch was under lubricated, was damaged internally, and
had some incorrect parts fitted ( specifically short pawls ) and that it had
"rolled over" in the opposite direction. I assume this means that the
freewheel direction had reversed. There is also available an audio of the
crash. Jane Dornacker was on air at the time. In the background, it seems
the engine can be heard overspeeding, certainly revving freely with no load
on it. Perhaps the engine didn't fail, the sprag clutch just let go ( hence
engine sounds in the audio ) and in the panic he pulled pitch. The report
says they were only at about 75 feet.

Mark

"Mark" wrote:

on it. Perhaps the engine didn't fail, the sprag clutch just let go ( hence
engine sounds in the audio ) and in the panic he pulled pitch. The report
says they were only at about 75 feet.

That would make sense. By the time he realized that the running
engine wasn't driving the rotors, it was too late.

Dennis H.

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

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."

To find out what an H-1B is and how Congress is using
them to put Americans out of work, visit the following
web site and click on the "Exporting America" CNN news
video: http://zazona.com/ShameH1B/MediaClips.htm

"Bart" wrote in message
...
Not true in many (most) turbines.

wrote:
On most helicopters that I have been in, testing the split (sprag
clutch) is part of the power on preflight. It seems kind of odd that
such a catastophic clutch failure would occur without warning in the
preflight. Perhaps they skipped that step.

I remember part of the Bell Jetranger preflight was to turn the blades by
hand to 90/270, and you were supposed to turn them counter clockwise (the
direction of normal rotation), I can't remember the reason why that
particular direction was specified. Maybe so as to not spin the power
turbine (and engine RGB) without proper lubrication, maybe it was to check
for sprag clutch disengagement, maybe both reasons.

As for testing the _engagement_ of the clutch on preflight, my first thought
is that it is impractical. Even on a small ship like the Scorpion, the main
rotor may normally experience several hundred pounds-feet of torque...

For another data point, I can say that checking the freewheeling unit(s) is
not a part of the H-60 preflight, the navalized version anyway.

On a related anecdote, when one of my friends was a student pilot, he had a
hard landing when the sprag clutch failed to reengage following a practice
power recovery autorotation. It freewheeled just fine though, and it
engaged fine up until before the auto. That is the only time I ever heard
of such a thing happening.

Actually, the preflight maneuver was to spin them clockwise 360 degs.
The reason you did that was to check for coke-ing of the turbine.
Older C20-s had a problem with this, and by spinning the blades
backwards you would also be spinning the turbine and you can hear
and feel it. I've never heard of the opposite rotation being done,
but im sure someone else will come up with a reason that it was.
btw: spinning the turbine is still part of the postflight of the
MD500, I was told that its because of the crazy engine angle.

The reason for the 90 / 270 thing was to ensure that they were not
still tied to the tailboom. One of the funniest/scary stories I heard
was that during a maintenance run-up the pilot checked for the 90/270
blades, fired up the turbine, and then noticed (too late) that the
mechanic had secured the blades to one of those large rolling toolboxes.
The box rolled around and did some serious damage before the pilot
could stop it. No one was hurt that I know of though.

Bart

Jim Carriere wrote:
I remember part of the Bell Jetranger preflight was to turn the blades by
hand to 90/270, and you were supposed to turn them counter clockwise (the
direction of normal rotation), I can't remember the reason why that
particular direction was specified. Maybe so as to not spin the power
turbine (and engine RGB) without proper lubrication, maybe it was to check
for sprag clutch disengagement, maybe both reasons.

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)

"A RECESSION is when you know somebody who is out of work.
A DEPRESSION is when YOU are out of work.
A RECOVERY is when all the H-1B's are out of work."

To find out what an H-1B is and how Congress is using
them to put Americans out of work, visit the following
web site and click on the "Exporting America" CNN news
video: http://zazona.com/ShameH1B/MediaClips.htm