Dear Frans
[quote:f042f8651c]You first state that the lack of an end-stop in the Woodcomp
propellor was the cause. Later on, you blame diodes and relays of inferior
quality.
[/quote:f042f8651c]
Sorry, no. The fine pitch endstop is formed by two microswitches, parelled by
one
diode. Never mentioned a relay.
[quote:f042f8651c]These are two different things. Anyway, as someone else
pointed
out already, the accident implies more or less that the propellor control
motor got somehow engaged. A missing end stop was nothing more than a
contributing
factor, not the real cause.[/quote:f042f8651c]
Of course the pitch motor got engaged, not by mistake, but because the pilot, me
reduced throttle. The not-working endstop was the first failing part. A burned
out motor the second part. What real cause do you want?
[quote:f042f8651c]Since you had the reverse pitch
option, there could not be a mechanical end stop anyway. [/quote:f042f8651c]
Irrelevant: Not any Woodcomp SR 3000 has a mechanical stop.
Read my lips: Normal, reverse, feathering: No mechanical endstops.
[quote:f042f8651c]But even without the end stop, the prop would have functioned
correctly, IF the prop pitch motor got not erroneously engaged during the
flight.
The big question therefor remains: what caused the prop motor to start cranking
the prop to superfine?[/quote:f042f8651c]
Iv've tried to explain that, let's try again, real slow now, for the technically
handicapped amongst us.
Say you fly at 100 knots, and the controller has adjusted the rpm, as you have
demanded, to 5000 rpm.
Now, if you reduce throttle slightly the controller reduces the pitch to
maintain
the 5000 rpm that you asked for. Right?
It will keep reducing the pitch at any further reducing of throttle, to keep up
the RPM. The controller has no idea how fine it turns the blades.
Only the endswitch will prevent the blades from turning into superfine or even
further.
Nothing strange about that, and nothing to worry about,
IF THE ENDSTOPS ARE WORKING!
[quote:f042f8651c]Some of us are intrigued by a message from you, written the
19th
of may 2007, in which you wrote:
"For reason of simplicity, exactly in a high stress situation (most of
my landings will be :-) ) managed to do away with the change-mode
switch. The 3-pole reverse-unreverse switch now operates a relay, that
changes the mode. This latched and warning labeled switch is IMHO
security enough against accidental operation. [/quote:f042f8651c]
Some of us? Intrigued?
I fail to see where this connects to this thread other then do distract from the
facts.
[quote:f042f8651c]Could it be that your safety bypass, consisting of the
addition
of a
relay, played a role in this accident? Was this the malfunctioning relay
you are referring to? If this single additional relay would fail, could
it all by itself unintentionally power up the pitch control
motor?[/quote:f042f8651c]
Safety bypass? Please!
If "my" relay would fail, it would either blow the CB immediatly, leaving the
pitch
unchanged, or simply leave the pitch motor without power, again leaving the
pitch unchanged. The actual switching was done by a 4 pole 3 way switch. That
switch could only do what it was supposed to do. I've shown the circuit to
experts, and i have had the actual wiring checked by my inspector. His comment
was "Better standard of wiring then seen sofar on experimentals"
You are classifying a pretty fail-safe setup as a safety bypass, without even
knowing
the details.
[quote:f042f8651c]I hope you understand that I'm confused by your claim that it
was just a missing mechanical end stop that was the main cause of the accident.
[/quote:f042f8651c]
You really can't read. Never said that. I doubt very much if this is caused by
confusion or else. You seem to be constructing things. It's a pity.
And believe me, wish you all the luck you will need.
Regards,
Jos Okhuijsen
Visit - www.EuropaOwners.org
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