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VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE

 
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cakeykev(at)gmail.com
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PostPosted: Tue Sep 12, 2017 6:35 am    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Been through the same cabin ventilation issues tried negative pressure but carbon monoxide in cockpit and a blast of air from my fuel selector location in the tunnel.

I now have 3d printed deflectors on inside of air vents to direct air to blow over body/face and an extra air vent on top of the cockpit also 3d printed with a closable moveable vent inside to direct the air where required. It works well but did take me 7 versions to get right.

Tested in SW France this summer.

Kevin Challis
G ODJG
Quote:
On 12 Sep 2017, at 15:02, willydewey <willydewey(at)gmail.com> wrote:



I recently returned from a summer trip to Germany and Austria in G-IANI
wonderful trip but temperatures at 2000 ft rose in the cockpit to 44 deg C
and CO2 from the exhaust bothered me most of the time..
When on the ground the 914 was a problem to start probably by fuel being evaporated in the carbs and consequential vapour lock
I have the Standard NACA vents (broken but open) but these didnt work at all well. Ian gave me a Mecaplex vent which unfortunalty doesnt match the curve of the screen and maybe it would if fitted foul the locking handle.
During the winter months I would like to redress the situation and would be grateful for advice, in screen vents for example. Is it feasible to block or restrict the entrance where the flap drive enters the fuselage? If this is possible the CO2 problem might improve
Any help or tips much appreciated.
I do have the vapour return line installed back to the tank as required by the LAA and was recently checked and a logbook entry made.
Once started from cold the 914 ran faultlessly even in those high temperatures Both cylinder head and oil temperatures were within limits.

--------
Give a wise man knowledge and he will be yet wiser




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dpark748(at)me.com
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PostPosted: Tue Sep 12, 2017 6:56 am    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Simple and very effective available from ac spruce.


Dave Park G-LDVO
Quote:
On 12 Sep 2017, at 15:33, Kevin Challis <cakeykev(at)gmail.com> wrote:



Been through the same cabin ventilation issues tried negative pressure but carbon monoxide in cockpit and a blast of air from my fuel selector location in the tunnel.

I now have 3d printed deflectors on inside of air vents to direct air to blow over body/face and an extra air vent on top of the cockpit also 3d printed with a closable moveable vent inside to direct the air where required. It works well but did take me 7 versions to get right.

Tested in SW France this summer.

Kevin Challis
G ODJG


> On 12 Sep 2017, at 15:02, willydewey <willydewey(at)gmail.com> wrote:
>
>
>
> I recently returned from a summer trip to Germany and Austria in G-IANI
> wonderful trip but temperatures at 2000 ft rose in the cockpit to 44 deg C
> and CO2 from the exhaust bothered me most of the time..
> When on the ground the 914 was a problem to start probably by fuel being evaporated in the carbs and consequential vapour lock
> I have the Standard NACA vents (broken but open) but these didnt work at all well. Ian gave me a Mecaplex vent which unfortunalty doesnt match the curve of the screen and maybe it would if fitted foul the locking handle.
> During the winter months I would like to redress the situation and would be grateful for advice, in screen vents for example. Is it feasible to block or restrict the entrance where the flap drive enters the fuselage? If this is possible the CO2 problem might improve
> Any help or tips much appreciated.
> I do have the vapour return line installed back to the tank as required by the LAA and was recently checked and a logbook entry made.
> Once started from cold the 914 ran faultlessly even in those high temperatures Both cylinder head and oil temperatures were within limits.
>
> --------
> Give a wise man knowledge and he will be yet wiser
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=472829#472829
>
>
>
>
>
>
>
>
>

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rlborger(at)mac.com
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PostPosted: Tue Sep 12, 2017 4:53 pm    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Will,
I’d have to recommend the Ultimate Ventilator available through Aircraft Spruce. ( http://www.europaowners.org/main.php?g2_itemId=63921 & http://www.aircraftspruce.com/catalog/appages/ultimatevent.php?clickkey=29703 ) I have them installed on my Europa and they do an excellent job of getting air into the cockpit. They aren’t cheap, but I guess this is a case of getting what you pay for.

Just my 2¢, YMMV.

Blue skies & tailwinds,Bob BorgerEuropa XS Tri, Rotax 914, Airmaster C/S Prop (75 hrs).Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP3705 Lynchburg Dr.Corinth, TX 76208-5331Cel: 817-992-1117rlborger(at)mac.com (rlborger(at)mac.com)

On Sep 12, 2017, at 9:02 AM, willydewey <willydewey(at)gmail.com (willydewey(at)gmail.com)> wrote:
--> Europa-List message posted by: "willydewey" <willydewey(at)gmail.com (willydewey(at)gmail.com)>I recently returned from a summer trip to Germany and Austria in G-IANIwonderful trip but temperatures at 2000 ft rose in the cockpit to 44 deg Cand CO2 from the exhaust bothered me most of the time..When on the ground the 914 was a problem to start probably by fuel being evaporated in the carbs and consequential vapour lockI have the Standard NACA vents (broken but open) but these didnt work at all well. Ian gave me a Mecaplex vent which unfortunalty doesnt match the curve of the screen and maybe it would if fitted foul the locking handle.During the winter months I would like to redress the situation and would be grateful for advice, in screen vents for example. Is it feasible to block or restrict the entrance where the flap drive enters the fuselage? If this is possible the CO2 problem might improveAny help or tips much appreciated.I do have the vapour return line installed back to the tank as required by the LAA and was recently checked and a logbook entry made.Once started from cold the 914 ran faultlessly even in those high temperatures Both cylinder head and oil temperatures were within limits.--------Give a wise man knowledge and he will be yet wiser


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ploucandco



Joined: 16 Sep 2007
Posts: 69

PostPosted: Wed Sep 13, 2017 12:36 am    Post subject: Re: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

For measuring CO levels, I purchased beg of this year this one
https://sensorcon.com/collections/carbon-monoxide-meters/products/portable-carbon-monoxide-detector-meter?variant=4193480964
less than US100 with aircraft2017 as discount tag when entered at purchase.

I understood that the firewall of my plane was far from being hermetic and also got much CO entering via the naca on the port side. After closing everything with transparent tape (naca) or alu tape (firewall), now I get 5-7 ppm in flight, about the same as on the gound without engine running.
When engine is running on the ground/taxi, I can get 30+ ppm as the exhaust gaz is entering via the monowheel tunnel.

So placement of any air intake device on the port side is crucial. I saw some who have air intake from the top cockpit. That seems the smartest approach to avoid CO ingress.

Concerning the startup issue on a hot 914, just disable both fuel pump before startup. This avoids flooding the carbs. Start your engine, run it at +-2500rpm and wait till that it start to die from lack of fuel. Enable your main fuel pump and you are ready to go.


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willydewey



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PostPosted: Wed Sep 13, 2017 4:56 am    Post subject: Re: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Thanks Kevin for the trouble in replying.....much appreciated
I have spent a while on different mouldings fixed to NACA vents without much sucess regretfully.. I will persue more experimentation and perhaps the vents suggested by the next contributer.. As they say every little helps

Thanks once again

Bill


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willydewey



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PostPosted: Thu Sep 14, 2017 7:48 am    Post subject: Re: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Thanks Guys for your inputs regarding ventilation. Food for thought indeed.
i will mull over your replies but I favour(favor) high level vents placed well up from the exhaust outlet. Not sure which ones yet.
Pete Jeffers has suggested that fumes may be getting in through the vent pipe that was put in from the baggage wall to somewhere near the tail Another invesigation I Guess.
Thanks all for your help and interest
Bill Dewey


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PostPosted: Thu Sep 14, 2017 9:01 am    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Bill, Have you thought of getting yourself a domestic carbon monoxide monitor which comes with a readout of CO concentration + indication of how serious/lethal that concentration is. Sell for around £30 in UK. After being exposed to near lethal levels when a plane I was test flying shed its exhaust stub, I feel every plane should have one! But it also let memove it around in my plane and find put where the fumes were coming from which for me was from the slots in the exhaust stub where it is clamped onto the silencer - fixed with fire cement.
Regards, David Joyce, GXSDJ


On 2017-09-14 16:48, willydewey wrote:
Quote:
Quote:
--> Europa-List message posted by: "willydewey" <willydewey(at)gmail.com (willydewey(at)gmail.com)>

Thanks Guys for your inputs regarding ventilation. Food for thought indeed.
i will mull over your replies but I favour(favor) high level vents placed well up from the exhaust outlet. Not sure which ones yet.
Pete Jeffers has suggested that fumes may be getting in through the vent pipe that was put in from the baggage wall to somewhere near the tail Another invesigation I Guess.
Thanks all for your help and interest
Bill Dewey

--------
Give a wise man knowledge and he will be yet wiser


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clivesutton



Joined: 23 Jan 2013
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PostPosted: Thu Sep 14, 2017 11:58 pm    Post subject: Re: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

If i may chip in on this:

I have two of the Ultimate Ventilators - each fitted in the side quarter section of the windscreen. Though ridiculously expensive, they work well when you need a blast of cold air - and their design helps to be able to direct that air blast.

I have a Fireangel CO monitor mounted on the firewall part of the parcel shelf facing the P2 seat (that i fitted with an 'off' switch to try and improve battery life). It's interesting to note how the CO levels vary on a flight:

a) The levels are <20 with the vents closed and engine running on the ground
b) CO levels go up to around 40-50 on max power/climb-out, but reduce with cruise throttle settings to around 25-35. I should probably do an extended max engine speed on the ground test to see if/how the movement of the whole airframe affects the levels. I'm confident that my structure/firewall is well-sealed.
c) CO levels go down if the vents are opened in flight - though i have not checked yet if they are letting in some of the engine-bay air from the shark gill vents in the upper cowling as they scoop the slipstream air that flows past it or if there is any variation side to side.

I would suggest there is another consideration - the exhaust stub fit into the silencer 'sockets. Speaking with Chris Piper of CKT, they make two kinds of stub end, one simply swaged from straight pipe (for pusher engines) and another that is a more precision part welded to the end of the pipe (for tractor configurations). The latter would reduce the exhaust leak due to its better fit. The joints are always moving of course - hence the recommendation to use Moly?*%? grease between the socket in the silencer and the pipe stub 'ball' joint.

Ii's also interesting to see the variation in what different countries consider to be hazardous concentrations of CO. 1-70 effects are apparently uncertain whilst in the US the limits are half that. Perhaps one of our medical colleagues would like to comment?

The learning continues . . .


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PostPosted: Fri Sep 15, 2017 12:39 am    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Clive, Replying to your suggestion that perhaps one of our medical friends will comment on the significance of lower levels of carbon monoxide exposure, my answer would be that anyone who has taken the trouble to read Wikipedia on the subject is likely to know as much or more than the majority of doctors who are not working in toxicology! I would say that no carbon monoxide is best to aim for but moderate levels only put you in the same state as a smoker ( I guess without the cancer risks), but you will have worked that out for yourself!
Regards, David Joyce, GXSDJ


On 2017-09-15 08:58, clivesutton wrote:
Quote:
Quote:
--> Europa-List message posted by: "clivesutton" <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)>

If i may chip in on this:

I have two of the Ultimate Ventilators - each fitted in the side quarter section of the windscreen. Though ridiculously expensive, they work well when you need a blast of cold air - and their design helps to be able to direct that air blast.

I have a Fireangel CO monitor mounted on the firewall part of the parcel shelf facing the P2 seat (that i fitted with an 'off' switch to try and improve battery life). It's interesting to note how the CO levels vary on a flight:

a) The levels are


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h&jeuropa



Joined: 07 Nov 2006
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PostPosted: Fri Sep 15, 2017 5:50 am    Post subject: Re: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Remi Guerner shows his solution to this problem in Europa Flyer Issue 84, page 17. It's simple and Remi says it works well.

Jim Butcher


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PostPosted: Fri Sep 15, 2017 10:14 am    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

These indicators have three levels but not parts per million? And rely on you seeing it before you nod off to sleep!
[img]cid:9C123957-69FB-4D8B-9D16-D54427D56091[/img]
Dave Park


On 15 Sep 2017, at 09:37, davidjoyce(at)doctors.org.uk (davidjoyce(at)doctors.org.uk) wrote:
Quote:

Clive, Replying to your suggestion that perhaps one of our medical friends will comment on the significance of lower levels of carbon monoxide exposure, my answer would be that anyone who has taken the trouble to read Wikipedia on the subject is likely to know as much or more than the majority of doctors who are not working in toxicology! I would say that no carbon monoxide is best to aim for but moderate levels only put you in the same state as a smoker ( I guess without the cancer risks), but you will have worked that out for yourself!
Regards, David Joyce, GXSDJ


On 2017-09-15 08:58, clivesutton wrote:
Quote:
Quote:
--> Europa-List message posted by: "clivesutton" <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)>

If i may chip in on this:

I have two of the Ultimate Ventilators - each fitted in the side quarter section of the windscreen. Though ridiculously expensive, they work well when you need a blast of cold air - and their design helps to be able to direct that air blast.

I have a Fireangel CO monitor mounted on the firewall part of the parcel shelf facing the P2 seat (that i fitted with an 'off' switch to try and improve battery life). It's interesting to note how the CO levels vary on a flight:

a) The levels are


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.com
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Fred Klein



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PostPosted: Fri Sep 15, 2017 11:34 am    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Quote:
On Sep 14, 2017, at 11:38 AM, Brian Davies <brian.davies44(at)gmail.com (brian.davies44(at)gmail.com)> wrote:
I had a CO problem about a year ago and carried out some investigation. The big clue, found by using a CO meter, was that the CO doubled when the flaps were down. I talked to Andy Draper who said the exhaust gases could enter via the flap slots and travel forwards through the tunnel and into the cockpit via the various control slots. I resisted cleaning my aircraft for a period and traced exhaust stains along the fuselage that travelled to the (Trigear) leg/fuse join and up to the flap slot.

These enhanced wing root fairings cover the flap slot…
Also…one of the reasons my bird has yet to fly...

[img]cid:9FD605E2-0485-440D-9B19-C2BFBCE7C839(at)Home[/img]
[img]cid:E0075722-EE68-4CC8-B4B2-6D6CA1E9B9E3(at)Home[/img]

[img]cid:7D5F68EB-C1AD-431C-959A-F7E2B326662E(at)Home[/img]

[img]cid:DFD3498F-3DBE-4BD0-8FFD-C35F517207B5(at)Home[/img]


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PostPosted: Sat Sep 16, 2017 1:41 am    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

I use a household carbon monoxide detector and it works great. Detects low levels over a period of time rather than just high levels. You can here it with headsets on.

Kevin Challis

On 15 Sep 2017, at 19:12, david park <dpark748(at)me.com (dpark748(at)me.com)> wrote:
Quote:
These indicators have three levels but not parts per million? And rely on you seeing it before you nod off to sleep!
<image1.gif>
Dave Park


On 15 Sep 2017, at 09:37, davidjoyce(at)doctors.org.uk (davidjoyce(at)doctors.org.uk) wrote:
Quote:

Clive, Replying to your suggestion that perhaps one of our medical friends will comment on the significance of lower levels of carbon monoxide exposure, my answer would be that anyone who has taken the trouble to read Wikipedia on the subject is likely to know as much or more than the majority of doctors who are not working in toxicology! I would say that no carbon monoxide is best to aim for but moderate levels only put you in the same state as a smoker ( I guess without the cancer risks), but you will have worked that out for yourself!
Regards, David Joyce, GXSDJ


On 2017-09-15 08:58, clivesutton wrote:
Quote:
Quote:
--> Europa-List message posted by: "clivesutton" <clive.maf(at)googlemail.com (clive.maf(at)googlemail.com)>

If i may chip in on this:

I have two of the Ultimate Ventilators - each fitted in the side quarter section of the windscreen. Though ridiculously expensive, they work well when you need a blast of cold air - and their design helps to be able to direct that air blast.

I have a Fireangel CO monitor mounted on the firewall part of the parcel shelf facing the P2 seat (that i fitted with an 'off' switch to try and improve battery life). It's interesting to note how the CO levels vary on a flight:

a) The levels are


Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=472897#472897
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ics.com
.com
.matronics.com/contribution





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PostPosted: Sat Sep 16, 2017 5:19 am    Post subject: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE Reply with quote

Fred and others,

Finding exhaust intrusion into the cockpit is not intuitive. Your very nice wing gap seal is the key to many of the exhaust intrusion problems.

From older posts on the subject:
NACA cockpit vents supplied in the kit placed low on the cockpit side, allow a direct inlet of exhaust gas to the pilots side.  Placing the vents on or near the fuselage glue line helps.

Always seal the wing root area well as the stock exhaust will arc up right into the leading edge of the wing and come in through the gap, enter the rigging hole and into the cockpit through the tunnel.

Mono wheel extension causes a draw behind the gear arm and can suck in exhaust into the wheel well. Holes in the wheel well around throttle, brake, gear handle etc. and a cockpit that has high draw out will exacerbate the problem.

Exhaust pipes should be long enough to move the exhaust well clear of the cockpit inlets. (This is where my nice short exhaust stack out of the 914 leaves a easily seen exhaust lead trace on the fuselage, that exhaust trace showed that during climb, exhaust gas goes from the pipe, and arcs directly up and over the wing root during climbs below 100 knots. My NACA cockpit vent is right in line with the exhaust trace. As you know I have my Ultimate Ventilators in my windscreen corners because of it.)

You can’t get quality air flow in the cockpit unless the cockpit is a low pressure. The lowest pressure area is on the top of the canopy. If the cockpit seals are not tight, this will lower the air pressure in the cockpit improving the draw of air into the cockpit and through the wheel well to cockpit holes.

The rear fuselage is generally a lower pressure area. I put vents or stand offs the D panel cover to exhaust air out of the cockpit and improve pressure vent performance. At low speed or high angles of attack the suction of air at the wing root fillet is quite high.

Jabiru exhaust pipes coming right out of the center cowl will, at high angles of attack, inject exhaust into the wheel well with the mono gear down. Pipes must be angled to clear the mono trailer arm for transport anyway so move the Jabiru pipes outboard and exhaust intrusion can be reduced also.

Trigear aircraft built with a sealed wheel well, rarely have an exhaust intrusion problem unless the cockpit vents are in line with the exhaust, or the wing gap seals are leaky.

Pay attention to the hole behind the wing root right where the flap and root come together. Looking into the wing root from behind the wing will show a direct path to the rigging hole and a direct cockpit gas entry. (I’ve never had a problem with this hole if the gap all around the wing fillet is sealed tightly.)

Mono wheels in the retracted position tend to have a large bubble of air causing pressure in the wheel well that makes for a high flow of air through the gear, brake and throttle slots in the wheel well making for a cold cockpit at altitude. Keep the gaps around the main wheel as small as possible. Silicone cowl seal or similar will reduce the gap in these slots and help keep dirt, grass and cold air out of the cockpit. (Exhaust also I guess.)

Just archive searching.

Regards,
Bud Yerly

Sent from Mail for Windows 10

From: Fred Klein (fklein(at)orcasonline.com)
Sent: Friday, September 15, 2017 3:42 PM
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: Re: VENTILATION IN FLIGHT & POSITIVE CABIN PRESSURE


Quote:

On Sep 14, 2017, at 11:38 AM, Brian Davies <brian.davies44(at)gmail.com (brian.davies44(at)gmail.com)> wrote:


I had a CO problem about a year ago and carried out some investigation. The big clue, found by using a CO meter, was that the CO doubled when the flaps were down. I talked to Andy Draper who said the exhaust gases could enter via the flap slots and travel forwards through the tunnel and into the cockpit via the various control slots.  I resisted cleaning my aircraft for a period and traced exhaust stains along the fuselage that travelled to the (Trigear) leg/fuse join and up to the flap slot.



These enhanced wing root fairings cover the flap slot…




Also…one of the reasons my bird has yet to fly...



[img]cid:9FD605E2-0485-440D-9B19-C2BFBCE7C839(at)Home[/img]


[img]cid:9FD605E2-0485-440D-9B19-C2BFBCE7C839(at)Home[/img]



[img]cid:9FD605E2-0485-440D-9B19-C2BFBCE7C839(at)Home[/img]



[img]cid:9FD605E2-0485-440D-9B19-C2BFBCE7C839(at)Home[/img]


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