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davidjoyce(at)doctors.org
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 Posted: Sun May 11, 2014 2:43 am Post subject: Europa Crash in Lübeck/Germany |
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Graham, Sorry to be butting in on your debate with Tim,
and I see where you are coming from now, but can I just
add that the SmartASS is g compensated so it gives exactly
the same 'margin over stall' information as an AOA device
(and at a fraction of the price). It might appear that I
am pushing this as if I had some commercial tie up, which
is not the case. I am evangelical about it because we have
now had (subject to confirmation in this latest case) 6
Europas lost to stall/spin accidents, an appalling
statistic for a plane that flies so beautifully and is
slippery enough not to lose speed rapidly. There have of
course been countless crashes of other types also, but in
our relatively small and tight knit Europa community it is
truly sobering and we should all be asking ourselves are
we confident of not becoming number 7.
Regards, David Joyce, G-XSDJ
On Sun, 11 May 2014 11:22:00 +0100 (BST)
GRAHAM SINGLETON <grahamsingleton(at)btinternet.com> wrote:
| Quote: | Tim
maybe we are mixing things a bit. ASI will measure
instantly changes in airspeed.
When AoA changes aircraft speed will not change
instantly but will take several seconds.
The force causing change of airspeed is increase or
decrease in drag, usually quite a small force.
During take off acceleration is caused by engine thrust
and ASI will record speed of course, as soon
as the aircraft is flying AoA should quickly settle at
best climb.
Stall occurs at the same AoA whatever airspeed or total
weight is. (I'm thinking aloud here)
In fact best climb, cruise or glide speeds are also at
fixed AoAs. They are not at fixed airspeeds but
change as all up weight changes.
AoA is much the best primary flight control instrument.
That's why fast jets use it.
A pity AoA meters aren't mass produced like ASIs are!
best regards
Graham
________________________________
From: houlihan <houlihan(at)blueyonder.co.uk>
To: europa-list(at)matronics.com
Sent: Sunday, 11 May 2014, 8:34
Subject: Re: Re:
Re: Re: Europa Crash in
Lübeck/Germany
Hi Graham.
We may be talking apples against pears here BUT if what
you say is true then on takeoff I would be at 100'
thinking about retracting the undercarriage before the
ASI has moved from zero.
I agree it takes time to accelerate or decelerate a
600kg mass but the pressure measurement showing movement
relative to the local air mass will be indicated within a
small fraction of a second even using our normal
mechanical manometers that are calibrated in airspeed and
could be even quicker using electronic pressure sensors
close to the pitot head.
True an AOA or alpha system would be helpful but I just
want to be warned if through lack of attention or being
distracted I allow my speed to decay , these lack of
attention or distraction events usually build up slowly
without it being noticed and I would guess rarely happens
over one or two seconds.
best regards
Tim
On 10 May 2014 22:28, GRAHAM SINGLETON
<grahamsingleton(at)btinternet.com> wrote:
Tim
>don't think so , the ASI won't move (or shouldn't!) until
>the aircraft has accelerated, or worse slowed down and
>that takes many seconds.
>When it says "stall speed!" you.ve already stalled. Not a
>lot of use.
>Graham
>________________________________
> From: houlihan <houlihan(at)blueyonder.co.uk>
>To: europa-list(at)matronics.com
>Sent: Saturday, 10 May 2014, 14:31
>Subject: Re: Re:
>Europa Crash in Lübeck/Germany
>
>Hi Graham.
>I think you may have put the decimal point in the wrong
>place. I appreciate what you are suggesting but 20
>seconds ?
>I bet the real figure is much less than a second.
>Mind you how would you measure the lag , my ASI seems to
>move at the speed of light at times.
>Tim
>
>On 10 May 2014 13:19, GRAHAM SINGLETON
><grahamsingleton(at)btinternet.com> wrote:
>
>Or an AoA meter as primary attitude/speed instrument. The
>ASI is always 20 seconds too late.
>>Very sad, I met Manfred while he was building. A very
>>nice man and a nice Europa.
>>Graham
>>
>>
>>
>>
>>
>>
>>________________________________
>> From: David Joyce <davidjoyce(at)doctors.org.uk>
>>To: europa-list(at)matronics.com
>>Sent: Saturday, 10 May 2014, 12:36
>>Subject: Re: Europa Crash in Lübeck/Germany
>>
>>
>>
>><davidjoyce(at)doctors.org.uk>
>>
>>
>>I strongly suspect that this another case where a
>>SmartASS or the equivalent might have saved them both.
>>David Joyce, G-XSDJ
>>
>>
>>
>>arget="_blank">http://www.matronics.com/Navigator?Europa-List
>>tp://forums.matronics.com
>>_blank">http://www.matronics.com/contribution
>
>http://www.matronics.com/con================
>arget="_blank">http://www.matronics.com/Navigator?Europa-List
tp://forums.matronics.com
_blank">http://www.========================
=======================
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davidjoyce(at)doctors.org
Guest
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| Posted: Sun May 11, 2014 7:10 am Post subject: Europa Crash in Lübeck/Germany |
|
|
Graham, You should probably be contacting Mark Burton for
a definitive answer to that, but my understanding is that
the mark 2 SmartASS and the upcoming mk 3 (as opposed to
the mk 1) have solid state accelerometers built in and
they modify the speed slow & speed very slow messages in
realtion to the increased g effect on stall speed so that
if you are set for 60 as your approach speed if you pull a
60 degree bank whilst maintaining 60kt she will get
agitated
and tell you 'speed slow' or probably 'very slow'. You are
of
course increasing the AOA to achieve that bank angle and
the signal would go from probably yellow to red and the
associated audible warnings on the new Bendix King AOA
system would show comparable change.
I accept that inaccurate profiling might
change
the stall speed and behaviour and favour a wing drop, but
nevertheless I feel strongly that the underlying critical
factor in the sort of disasters we are talking about is
allowing the speed to decay dramatically whilst heavily
distracted in a highly stressed situation. A slightly
inaccurate Classic wing might stall at say 42kts whilst my
beautiful XS wing stalls at 38 but neither of us should be
anywhere near these speeds unless moments from touch down!
In serious emergencies such as EFATOs even the most
experienced & qualified pilots can be distracted enough to
totally ignore speed control, so we all need a system that
points out in unignorable fashion that our speed is
getting dangerously slow, when we are looking out of the
window desperately trying to identify a place we might
land without killing ourselves. Student pilots are
significantly
more likely to die from stall/spin accidents with an
instructor
on board than flying solo. My (& I suspect most)
stall warner does not fit that bill. It is in the head
rest and advancing deafness and super new head sets mean
it is only just audible, and on top of that I am
used to ignoring it for much of the take off and landing
runs. Regards, David
On Sun, 11 May 2014 15:14:08 +0100 (BST)
GRAHAM SINGLETON <grahamsingleton(at)btinternet.com> wrote:
| Quote: | David
always respect your remarks so no apology needed. I need
to scratch my bald patch to understand the G compensation
aspect.
One of the things that disturbs me somewhat is that
several of these accidents were with Classics
Don's excellent airfoil section is very critical to
inaccuracy around the leading edge and I noticed that
sanding the LE with templates generated from computer
printouts made a big difference to the way the wing
stalled. A single stroke
in the wrong place with a flat abrasive sander can
destroy the LE profile.
regartds
Graham
________________________________
From: David Joyce <davidjoyce(at)doctors.org.uk>
To: europa-list(at)matronics.com Sent: Sunday, 11 May 2014,
11:42
Subject: Re: Re: Re:
Re: Re: Re:
Europa Crash in Lübeck/Germany
<davidjoyce(at)doctors.org.uk>
Graham, Sorry to be butting in on your debate with Tim,
and I see where you are coming from now, but can I just
add that the SmartASS is g compensated so it gives exactly
the same 'margin over stall' information as an AOA device
(and at a fraction of the price). It might appear that I
am pushing this as if I had some commercial tie up, which
is not the case. I am evangelical about it because we have
now had (subject to confirmation in this latest case) 6
Europas lost to stall/spin accidents, an appalling
statistic for a plane that flies so beautifully and is
slippery enough not to lose speed rapidly. There have of
course been countless crashes of other types also, but in
our relatively small and tight knit Europa community it is
truly sobering and we should all be asking ourselves are
we confident of not becoming number 7.
Regards, David Joyce, G-XSDJ
On Sun, 11 May 2014 11:22:00 +0100 (BST)
GRAHAM SINGLETON <grahamsingleton(at)btinternet.com> wrote:
> Tim
> maybe we are mixing things a bit. ASI will measure
>instantly changes in airspeed. When AoA changes aircraft
>speed will not change instantly but will take several
>seconds.
> The force causing change of airspeed is increase or
>decrease in drag, usually quite a small force.
> During take off acceleration is caused by engine thrust
>and ASI will record speed of course, as soon as the
>aircraft is flying AoA should quickly settle at best
>climb.
> Stall occurs at the same AoA whatever airspeed or total
>weight is. (I'm thinking aloud here)
> In fact best climb, cruise or glide speeds are also at
>fixed AoAs. They are not at fixed airspeeds but
> change as all up weight changes.
> AoA is much the best primary flight control instrument.
>That's why fast jets use it.
> A pity AoA meters aren't mass produced like ASIs are!
> best regards
> Graham
>
>
>
>
> ________________________________
> From: houlihan <houlihan(at)blueyonder.co.uk>
> To: europa-list(at)matronics.com Sent: Sunday, 11 May 2014,
>8:34
> Subject: Re: Re:
>Re: Re: Europa Crash in
>Lübeck/Germany
>
>
>
> Hi Graham.
>
> We may be talking apples against pears here BUT if what
>you say is true then on takeoff I would be at 100'
>thinking about retracting the undercarriage before the ASI
>has moved from zero.
>
> I agree it takes time to accelerate or decelerate a 600kg
>mass but the pressure measurement showing movement
>relative to the local air mass will be indicated within a
>small fraction of a second even using our normal
>mechanical manometers that are calibrated in airspeed and
>could be even quicker using electronic pressure sensors
>close to the pitot head.
>
> True an AOA or alpha system would be helpful but I just
>want to be warned if through lack of attention or being
>distracted I allow my speed to decay , these lack of
>attention or distraction events usually build up slowly
>without it being noticed and I would guess rarely happens
>over one or two seconds.
>
> best regards
>
> Tim
>
>
>
> On 10 May 2014 22:28, GRAHAM SINGLETON
><grahamsingleton(at)btinternet.com> wrote:
>
> Tim
>> don't think so , the ASI won't move (or shouldn't!) until
>>the aircraft has accelerated, or worse slowed down and
>>that takes many seconds.
>> When it says "stall speed!" you.ve already stalled. Not a
>>lot of use.
>> Graham
>>
>>
>>
>>
>>
>>
>> ________________________________
>> From: houlihan <houlihan(at)blueyonder.co.uk>
>> To: europa-list(at)matronics.com Sent: Saturday, 10 May
>>2014, 14:31
>> Subject: Re: Re:
>>Europa Crash in Lübeck/Germany
>>
>>
>>
>> Hi Graham.
>>
>>
>> I think you may have put the decimal point in the wrong
>>place. I appreciate what you are suggesting but 20 seconds
>>?
>> I bet the real figure is much less than a second.
>> Mind you how would you measure the lag , my ASI seems to
>>move at the speed of light at times.
>>
>>
>> Tim
>>
>>
>>
>>
>>
>> On 10 May 2014 13:19, GRAHAM SINGLETON
>><grahamsingleton(at)btinternet.com> wrote:
>>
>> Or an AoA meter as primary attitude/speed instrument. The
>>ASI is always 20 seconds too late.
>>> Very sad, I met Manfred while he was building. A very
>>>nice man and a nice Europa.
>>> Graham
>>>
>>>
>>>
>>>
>>>
>>>
>>> ________________________________
>>> From: David Joyce <davidjoyce(at)doctors.org.uk>
>>> To: europa-list(at)matronics.com Sent: Saturday, 10 May
>>>2014, 12:36
>>> Subject: Re: Europa Crash in Lübeck/Germany
>>>
>>>
>>>
>>><davidjoyce(at)doctors.org.uk>
>>>
>>>
>>> I strongly suspect that this another case where a
>>>SmartASS or the equivalent might have saved them both.
>>>David Joyce, G-XSDJ
>>>
>>>
>>>
>>> arget="_blank">http://www.matronics.com/Navigator?Europa-List
>>>tp://forums.matronics.com
>>>_blank">http://www.matronics.com/contribution
>>
>> http://www.matronics.com/con================
>> arget="_blank">http://www.matronics.com/Navigator?Europa-List
> tp://forums.matronics.com
> _blank">http://www.========================
> =======================================
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| | - The Matronics Europa-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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graeme bird
Joined: 15 Jul 2010
Posts: 434
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| Posted: Sun May 11, 2014 7:48 am Post subject: Re: Europa Crash in L�beck/Germany |
|
|
Is it a stall? my first thought was i would probably be putting the wheel away to get some climb about there; what if a flap pin was a bit short or the flap one side moved out board and only one was brought up?
Certainly those first few flights are risky even with the best inspections.
As for saying one wrong sweep when sanding the leading edge will radically affect the stall characteristics, is that true or help our cause? Perhaps a little alarmist - no sane builder is going to put a flat on it.
| | - The Matronics Europa-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Europa-List |
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_________________
Graeme Bird
kit4 (Wagstaff) TBD
Kit3 G-CLXU (Gregory) mono 914 xs Woodcomp
Kit2 G-PATS - (kesterton) Mono Classic 912 warpdrive
Kit 1 G-UMPY - Mono Classic/XS 912S, Woodcomp G(@)gdbmk.co.uk |
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