It isnt a matter of keeping people in the dark but of arriving at the
correct conclusion. IMHO it is far better to say nothing than to arrive at a
flawed judgement.
And as for this being a British phenomenon what sparked off Tony Blairs war
on Iraq. The assumption that they had WMD with little or no evidence to back
it up. OK, sorry for getting political.
It is to be commended that the PFA have responded so quickly to this
situation and I doubt very much if the answer is as clear cut as people may
wish. At the moment their priority is to prevent a recurrence of this tragic
accident even if it means barking up a few wrong trees. When they have had
the opportunity to fully consider the evidence I am sure we will be amongst
the first to hear.
Purely on the speculation that one of the tailplanes may have moved outboard
and disengaged the drive pins it is a possibility. However I think it highly
unlikely that the disengaged tailplane could have "turned square" as has
been suggested. If you consider the area of tailplane foreward of the torque
tube as compared with the area behind, air pressure would keep the tailplane
in line with the aircraft. I suspect that once disengaged from the drive
pins the unrestrained tailplane would start to oscillate and then flutter.
What effect this disengagement would have on the remaining tailplane is hard
to predict. True there would now be an imbalance in the tailplane assembly
but any force exerted by the mass balance arm could be counteracted by force
applied to the control column. Have you never sat in the plane withouthe
tailplanes connected and moved the stick back and forth. It is heavy but not
impossible to move.
As for it being unlikely that flutter would occur at 90kts my understanding
is that flutter can happen at any speed. What speed does it take to cause
flags to flutter in the wind 10-20knots (even less).
I believe that if there had been a straightford and simple explanation, we
would have heard by now. It is in nobodys interests to keep us in the dark.
----- Original Message -----
From: "Jos Okhuijsen" <josok-e@ukolo.fi>
Sent: Saturday, June 23, 2007 2:13 PM
Subject: Re: Europa-List: Wikipedia's entry on flutter
>
> Hi William H.
>
>> We still can't avoid the question: why did this happen WHEN it did? Mark
>> makes a good point about slop, in any case, slop would normally built up
>> slowly. David's information about speed seems to rule that out as a
>> trigger event. Just a thought, but if one of the stabs became
>> disengaged, for any reason (sideways movement, loss of TP14D pin -
>> secured by a single small split pin) from the TP12/13 drive flange,
>> presumably the other stab would instantly be countering all of the mass
>> in the TP19 weights, thereby creating a sudden and huge mass imbalance -
>> enough to cause catastrophic flutter?
>
> Somebody from the UK told me once: We are like mushrooms. We are kept in
> the dark, and once in a while we are allowed to see the light, and
> somebody throws shit at us. In this case i get the same feeling.
>
> Talking to Graham last night, we decided that at 90 knots there is very
> little chance of flutter. But the load on the tailplane is minimal at that
> speed. Now, if TP6 was loose, this was the time for the tail plane to move
> out wards, disengage from the TP 12 pins and turn square to the direction
> of flight, and so destroy itself, shake a wing loose and destroy the
> plane. Not necessarily in that order. But as said,we are kept in the dark
> and so on, so this is just another speculation.
>
> Regards,
>
> Jos Okhuijsen
>
> http://www.europaowners.org/kit600
>
>
>
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