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peterz(at)zutrasoft.com
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 Posted: Sun May 11, 2014 3:27 am Post subject: Europa-List: Re: Europa-List: Re: Europa-List: Re: Europa-L |
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grahamsingleton(at)btinte
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| Posted: Sun May 11, 2014 6:17 am Post subject: Europa-List: Re: Europa-List: Re: Europa-List: Re: Europa-L |
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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: Europa-List: Re: Re: Re: Europa Crash in Lübeck/Germany
--> Europa-List message posted by: "David Joyce" <davidjoyce(at)doctors.org.uk (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 (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 (houlihan(at)blueyonder.co.uk)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com) Sent: Sunday, 11 May 2014, 8:34
Subject: Re: Re: Europa-List: 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 (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 (houlihan(at)blueyonder.co.uk)>
> To: europa-list(at)matronics.com (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 (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 (davidjoyce(at)doctors.org.uk)>
>> To: europa-list(at)matronics.com (europa-list(at)matronics.com) Sent: Saturday, 10 May 2014, 12:36
>> Subject: Re: Europa Crash in Lübeck/Germany
>>
>>
>> --> Europa-List message posted by: "David Joyce" <davidjoyce(at)doctors.org.uk (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.========================
==================== --> http://www.matronics.com/Navigator?Europa-List
_sp; - MATRONICS = -->
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grahamsingleton(at)btinte
Guest
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| Posted: Sun May 11, 2014 6:19 am Post subject: Europa-List: Re: Europa-List: Re: Europa-List: Re: Europa-L |
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I also respect Mark Burton's work although I did fail to persuade him to use AoA..
Graham
From: David Joyce <davidjoyce(at)doctors.org.uk>
To: europa-list(at)matronics.com
Sent: Sunday, 11 May 2014, 11:42
Subject: Re: Europa-List: Re: Re: Re: Re: Europa-List: Re: Europa Crash in Lübeck/Germany
--> Europa-List message posted by: "David Joyce" <davidjoyce(at)doctors.org.uk (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 (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 (houlihan(at)blueyonder.co.uk)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com) Sent: Sunday, 11 May 2014, 8:34
Subject: Re: Re: Re: Europa-List: 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 (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 (houlihan(at)blueyonder.co.uk)>
> To: europa-list(at)matronics.com (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 (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 (davidjoyce(at)doctors.org.uk)>
>> To: europa-list(at)matronics.com (europa-list(at)matronics.com) Sent: Saturday, 10 May 2014, 12:36
>> Subject: Re: Europa Crash in Lübeck/Germany
>>
>>
>> --> Europa-List message posted by: "David Joyce" <davidjoyce(at)doctors.org.uk (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.========================
=============== Use the Matronics List Features Navigator to //www.matronics.com/Navigator?Europa-List" target="_blank">http://www.mat; ronics.com/contribution" target="_blank">http://www.matronics.com/contrib===============
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