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frans(at)privatepilots.nl
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 Posted: Fri Oct 05, 2012 7:36 am Post subject: Fwd: Europa cooling |
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Hi everyone,
I got numerous requests for pictures, so I assume this is of "general
interest".
I still plan to write an article about this, but so far I didn't find
the time.
So, for all of you who are through waiting, here some low quality
pictures to get some idea of what I have done.
I'm reluctant to show these pictures, these pictures were taken when the
work was still in progress, to discuss these things in a private group.
Since then the cowling has been cleaned up, received a new finish and
paint. For the final pictures I will also choose a more appealing
background and clean up the tools. 
On some of the pictures you still see two small holes where the original
cowling vents once were. These holes proved to be unnecessary and have
been eliminated in the final version.
The two ram air inlets and radiator inlet are the only air entries in
the cowling. The air exiting the radiator also takes the heat of the
exhaust, turbo and silencer with it. No further cowling cooling was
necessary.
The two lower ram air inlets:
The starboard inlet is for the engine air and via a butterfly valve to
the intercooler.
The port inlet is for cylinder cooling air.
A few pictures show the cowl flap wide open. Due to the length of the
cowl flap the angle is still moderate and it looks like it is only a
little bit open.
Also some pictures with the exhaust augmenter.
And of course the interior of the cowling, to see how I have set up the
intercooler and cylinder cooling.
Frans
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graeme bird
Joined: 15 Jul 2010
Posts: 434
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| Posted: Fri Oct 05, 2012 8:34 am Post subject: Re: Fwd: Europa cooling |
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nice pics, what diameter prop have you got there? I have two good wide woodcomp blades. I was told at 1625 they would not be effective on anything.
| | - 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
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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frans(at)privatepilots.nl
Guest
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| Posted: Fri Oct 05, 2012 8:51 am Post subject: Fwd: Europa cooling |
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On 10/05/2012 06:36 PM, graeme bird wrote:
| Quote: | nice pics, what diameter prop have you got there? I have two good
wide woodcomp blades. I was told at 1625 they would not be effective
on anything.
|
I have the largest diameter available (I don't remember how much that
is). In fact, I had to extent the nose wheel shaft to keep enough
clearance margin on a rough strip with a flat tire. The prop performs
very well though. With two blades vs three there is a bit more vibration
but there is one less prop leading edge plowing through the air,
reducing some prop drag.
Frans
| | - 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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N6ZY
Joined: 08 Aug 2011
Posts: 31
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| Posted: Fri Oct 05, 2012 9:57 am Post subject: Fwd: Europa cooling |
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Frans,
Thanks for posting the photos. That is an impressive scheme that you created, especially as it obviously works. As a matter of interest, what difference do you see in aircraft performance? Your cooling drag must be well down on the standard scheme.
Jerry
On Oct 5, 2012, at 12:27 PM, Frans Veldman wrote:
| Quote: | Hi everyone,
I got numerous requests for pictures, so I assume this is of "general
interest".
I still plan to write an article about this, but so far I didn't find
the time.
So, for all of you who are through waiting, here some low quality
pictures to get some idea of what I have done.
I'm reluctant to show these pictures, these pictures were taken when the
work was still in progress, to discuss these things in a private group.
Since then the cowling has been cleaned up, received a new finish and
paint. For the final pictures I will also choose a more appealing
background and clean up the tools.
On some of the pictures you still see two small holes where the original
cowling vents once were. These holes proved to be unnecessary and have
been eliminated in the final version.
The two ram air inlets and radiator inlet are the only air entries in
the cowling. The air exiting the radiator also takes the heat of the
exhaust, turbo and silencer with it. No further cowling cooling was
necessary.
The two lower ram air inlets:
The starboard inlet is for the engine air and via a butterfly valve to
the intercooler.
The port inlet is for cylinder cooling air.
A few pictures show the cowl flap wide open. Due to the length of the
cowl flap the angle is still moderate and it looks like it is only a
little bit open.
Also some pictures with the exhaust augmenter.
And of course the interior of the cowling, to see how I have set up the
intercooler and cylinder cooling.
Frans
<20110523_003.jpg><20110523_005.jpg><20110523_007.jpg><20110523_008.jpg><20110523_009.jpg><20110523_010.jpg><20110523_011.jpg><20110523_015.jpg>
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frans(at)privatepilots.nl
Guest
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| Posted: Fri Oct 05, 2012 11:06 am Post subject: Fwd: Europa cooling |
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On 10/05/2012 07:56 PM, Jeremy Fisher wrote:
| Quote: | Thanks for posting the photos. That is an impressive scheme that you
created, especially as it obviously works. As a matter of interest,
what difference do you see in aircraft performance? Your cooling
drag must be well down on the standard scheme.
|
I think it is, but of course it is hard to measure and judge. We also
have an efficient prop and Fred Klein's wing root fairings. On the other
hand the aircraft is a tri-gear, hi-top, and quite heavy. We never flew
with the stock cooling configuration, or without the wing root fairings,
etc.
We usually cruise with 27" to 28" of manifold pressure, and see an IAS
of about 130 knots at MTOW. At 100% we see a speed of 157 knots.
Usually at FL95 or so we see cruise speeds of 140-160 knots.
Measuring speeds drive me nuts. The aircraft seems to stick to a certain
speed, but pull up, dive down, and after the dive the aircraft maintains
a much higher speed than before the dive. I have heard this from more
people. Anyone who knows the cause? And then it looks like more weight
in the back is beneficial, but only to a certain point. I'm still at a
loss about how to get the best speeds.
Frans
| | - 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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N6ZY
Joined: 08 Aug 2011
Posts: 31
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| Posted: Fri Oct 05, 2012 6:07 pm Post subject: Fwd: Europa cooling |
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Frans,
I will probably regret this, but I will make some guesses as to why climbing and then diving causes the speed to increase.
It sounds to me as though you are seeing the airflow boundary layer detaching early somewhere on the airframe at lower speed. Then when you accelerate after climbing then diving the flow is staying attached. I cannot think of anything else that would explain what you are describing. Early airflow separation can cause a considerable increase in drag.
There may be another clue when you say that when you move the CG back, the speed increases to a point. By doing this, you are decreasing longitudinal static stability, but also reducing the download on the tailplane (or horizontal stab), causing a reduction in drag. Once the tailplane is aligned with the airflow, you have minimum drag from it. Move the CG back further the effect will taper off.
So it just could be that the airflow is detaching early on the lower surface of the tailplane in level flight at your initial cruising speed, increasing drag. By climbing, then accelerating in a dive, you may be allowing the airflow to stay attached later on the tailplane, reducing the drag. Then the reduced drag would allow you to maintain the increased speed. That is only a guess, and I have not flown a Europa so am free to speak through ignorance! You can check if I am right by carefully measuring the fore and aft position of the stick before you start the climb, then again once it is back in level flight after the dive. If it is slightly further forward after the dive, then this would confirm my guess.
If this does turn out to be the case, you might be able to delay the airflow separating by using small vortex generators on the bottom of the tailplane. An example for a different reason can be seen on the Zenith STOL aircraft (to allow earlier rotation on take off). You can see this at http://www.zenithair.com/stolch701/pic09/vg701elevator.jpg .
Now you can all tell me that I am wrong, and why!! Not many GA aircraft use an all-moving tail, and this may just be a side effect of that.
Jerry
On Oct 5, 2012, at 3:57 PM, Frans Veldman wrote:
| Quote: |
On 10/05/2012 07:56 PM, Jeremy Fisher wrote:
> Thanks for posting the photos. That is an impressive scheme that you
> created, especially as it obviously works. As a matter of interest,
> what difference do you see in aircraft performance? Your cooling
> drag must be well down on the standard scheme.
I think it is, but of course it is hard to measure and judge. We also
have an efficient prop and Fred Klein's wing root fairings. On the other
hand the aircraft is a tri-gear, hi-top, and quite heavy. We never flew
with the stock cooling configuration, or without the wing root fairings,
etc.
We usually cruise with 27" to 28" of manifold pressure, and see an IAS
of about 130 knots at MTOW. At 100% we see a speed of 157 knots.
Usually at FL95 or so we see cruise speeds of 140-160 knots.
Measuring speeds drive me nuts. The aircraft seems to stick to a certain
speed, but pull up, dive down, and after the dive the aircraft maintains
a much higher speed than before the dive. I have heard this from more
people. Anyone who knows the cause? And then it looks like more weight
in the back is beneficial, but only to a certain point. I'm still at a
loss about how to get the best speeds.
Frans
|
| | - 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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grahamsingleton(at)btinte
Guest
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| Posted: Sat Oct 06, 2012 12:55 am Post subject: Fwd: Europa cooling |
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Jeremy
It's a well known phenomenon called "putting the aircraft on the step". I think it's explained by the reduced power required when the aircraft slows down
compared to that required to accelerate to cruise speed.
When "on the step" the slightest clumsyness with the controls will cause a loss of a good 5 knots (with a monowheel) Noticed this when handing over to the right hand seat man
who kept the stick moving continouously, " that's how I was taught to fly!"
Graham
From: Jeremy Fisher <jffisher(at)gmail.com>
To: europa-list(at)matronics.com
Sent: Saturday, 6 October 2012, 3:06
Subject: Re: Europa-List: Fwd: Europa cooling
--> Europa-List message posted by: Jeremy Fisher <jffisher(at)gmail.com (jffisher(at)gmail.com)>
Frans,
I will probably regret this, but I will make some guesses as to why climbing and then diving causes the speed to increase.
It sounds to me as though you are seeing the airflow boundary layer detaching early somewhere on the airframe at lower speed. Then when you accelerate after climbing then diving the flow is staying attached. I cannot think of anything else that would explain what you are describing. Early airflow separation can cause a considerable increase in drag.
There may be another clue when you say that when you move the CG back, the speed increases to a point. By doing this, you are decreasing longitudinal static stability, but also reducing the download on the tailplane (or horizontal stab), causing a reduction in drag. Once the tailplane is aligned with the airflow, you have minimum drag from it. Move the CG back further the effect will taper off.
So it just could be that the airflow is detaching early on the lower surface of the tailplane in level flight at your initial cruising speed, increasing drag. By climbing, then accelerating in a dive, you may be allowing the airflow to stay attached later on the tailplane, reducing the drag. Then the reduced drag would allow you to maintain the increased speed. That is only a guess, and I have not flown a Europa so am free to speak through ignorance! You can check if I am right by carefully measuring the fore and aft position of the stick before you start the climb, then again once it is back in level flight after the dive. If it is slightly further forward after the dive, then this would confirm my guess.
If this does turn out to be the case, you might be able to delay the airflow separating by using small vortex generators on the bottom of the tailplane. An example for a different reason can be seen on the Zenith STOL aircraft (to allow earlier rotation on take off). You can see this at http://www.zenithair.com/stolch701/pic09/vg701elevator.jpg .
Now you can all tell me that I am wrong, and why!! Not many GA aircraft use an all-moving tail, and this may just be a side effect of that.
Jerry
On Oct 5, 2012, at 3:57 PM, Frans Veldman wrote:
| Quote: | --> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 10/05/2012 07:56 PM, Jeremy Fisher wrote:
> Thanks for posting the photos. That is an impressive scheme that you
> created, especially as it obviously works. As a matter of interest,
> what difference do you see in aircraft performance? Your cooling
> drag must be well down on the standard scheme.
I think it is, but of course it is hard to measure and judge. We also
have an efficient prop and Fred Klein's wing root fairings. On the other
hand the aircraft is a tri-gear, hi-top, and quite heavy. We never flew
with the stock cooling configuration, or without the wing root fairings,
etc.
We usually cruise with 27" to 28" of manifold pressure, and see an IAS
of about 130 knots at MTOW. At 100% we see a speed of 157 knots.
Usually at FL95 or so we see cruise speeds of 140-160 knots.
Measuring speeds drive me nuts. The aircraft seems to stick to a certain
speed, but pull up, dive down, and after the dive the aircraft maintains
a much higher speed than before the dive. I have heard this from more
people. Anyone who knows the cause? And then it looks like more weight
in the back is beneficial, but only to a certain point. I'm still at a
loss about how to get the best speeds.
Frans
nbsp; --> http://forums.matronics  tronics.com/contribution" target="_blank">http://www.matronics.com/contri================
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