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nigel_graham(at)m-tecque.
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 Posted: Mon Oct 29, 2012 2:02 am Post subject: Vapour lock? Why? |
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On 31/07/2012 22:27, klinefelter.kevin(at)gmail.com (klinefelter.kevin(at)gmail.com) wrote:
.....I was chatting with Rob Seaton ( of Rotech in canada). He said he learned how too small a fuel line and/or tortured routing can cause "cavitation" at the pumps. So maybe your fuel filter(s), on the suction side of the pump,are causing cavitation in the pump(s). Maybe due to the size (restriction of flow) of the filter, even if they are clean.
........ Snip
Kevin, I think Rob Seaton may be on the money with this one.
A year or so back, I experienced a dead cut while flying a friend's 914 powered Europa on a hot day. Nifty application of fuel pump restored the noise, but once safely back on the ground, I checked the filters (all clean). This aircraft was fitted with Europa specified Purolator glass shrouded filters that allow you to see the fuel flowing. At low RPM, the filter appeared full, but as power was increased, the filter began to fill with what I thought was air. My first action was to check the pipework and security of connections - but everything seemed fine - it was definitely not drawing in air from anywhere. I then concluded that I had experienced vapour lock and left it at that.
Curiosity got the better of me and I started researching cavitation and stumbled upon this very stilted, but interesting presentation on Youtube. Take a look at the first minute from 00.20 - in particular, the glass venturi. This was exactly what I saw in the Purolator filters.
http://www.youtube.com/watch?v=K_w3gcvA87I
My conclusion is that the Purolator filter has the correct mesh size to trap contaminants, but the filter capacity is too small and creates a pressure drop in the fuel line.
Nigel
[quote][b]
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grahamsingleton(at)btinte
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| Posted: Mon Oct 29, 2012 2:29 am Post subject: Vapour lock? Why? |
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Nigel
another problem with those filters is that sometimes they look clean but aren't because the contamination is translucent when wet with fuel; so, more restriction.
You're right, they are too small. quite high fuel flow with a 914.
Graham
From: "nigel_graham(at)m-tecque.co.uk" <nigel_graham(at)m-tecque.co.uk>
To: europa-list(at)matronics.com
Sent: Monday, 29 October 2012, 10:01
Subject: Re: Vapour lock? Why?
On 31/07/2012 22:27, klinefelter.kevin(at)gmail.com (klinefelter.kevin(at)gmail.com) wrote:
.....I was chatting with Rob Seaton ( of Rotech in canada). He said he learned how too small a fuel line and/or tortured routing can cause "cavitation" at the pumps. So maybe your fuel filter(s), on the suction side of the pump,are causing cavitation in the pump(s). Maybe due to the size (restriction of flow) of the filter, even if they are clean.
........ Snip
Kevin, I think Rob Seaton may be on the money with this one.
A year or so back, I experienced a dead cut while flying a friend's 914 powered Europa on a hot day. Nifty application of fuel pump restored the noise, but once safely back on the ground, I checked the filters (all clean). This aircraft was fitted with Europa specified Purolator glass shrouded filters that allow you to see the fuel flowing. At low RPM, the filter appeared full, but as power was increased, the filter began to fill with what I thought was air. My first action was to check the pipework and security of connections - but everything seemed fine - it was definitely not drawing in air from anywhere. I then concluded that I had experienced vapour lock and left it at that.
Curiosity got the better of me and I started researching cavitation and stumbled upon this very stilted, but interesting presentation on Youtube. Take a look at the first minute from 00.20 - in particular, the glass venturi. This was exactly what I saw in the Purolator filters.
http://www.youtube.com/watch?v=K_w3gcvA87I
My conclusion is that the Purolator filter has the correct mesh size to trap contaminants, but the filter capacity is too small and creates a pressure drop in the fuel line.
Nigel
[quote]http://www.matro====================
[b]
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wdaniell.longport(at)gmai
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| Posted: Mon Oct 29, 2012 3:32 am Post subject: Vapour lock? Why? |
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I plumbed those in – following the book – but I see they are probably not the ideal.
So what’s the most common solution?
Will
From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of GRAHAM SINGLETON
Sent: 29 October 2012 05:29
To: europa-list(at)matronics.com
Subject: Re: Vapour lock? Why?
Nigel
another problem with those filters is that sometimes they look clean but aren't because the contamination is translucent when wet with fuel; so, more restriction.
You're right, they are too small. quite high fuel flow with a 914.
Graham
From: "nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)" <nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Monday, 29 October 2012, 10:01
Subject: Re: Vapour lock? Why?
On 31/07/2012 22:27, klinefelter.kevin(at)gmail.com (klinefelter.kevin(at)gmail.com) wrote:
.....I was chatting with Rob Seaton ( of Rotech in canada). He said he learned how too small a fuel line and/or tortured routing can cause "cavitation" at the pumps. So maybe your fuel filter(s), on the suction side of the pump,are causing cavitation in the pump(s). Maybe due to the size (restriction of flow) of the filter, even if they are clean.
........ Snip
Kevin, I think Rob Seaton may be on the money with this one.
A year or so back, I experienced a dead cut while flying a friend's 914 powered Europa on a hot day. Nifty application of fuel pump restored the noise, but once safely back on the ground, I checked the filters (all clean). This aircraft was fitted with Europa specified Purolator glass shrouded filters that allow you to see the fuel flowing. At low RPM, the filter appeared full, but as power was increased, the filter began to fill with what I thought was air. My first action was to check the pipework and security of connections - but everything seemed fine - it was definitely not drawing in air from anywhere. I then concluded that I had experienced vapour lock and left it at that.
Curiosity got the better of me and I started researching cavitation and stumbled upon this very stilted, but interesting presentation on Youtube. Take a look at the first minute from 00.20 - in particular, the glass venturi. This was exactly what I saw in the Purolator filters.
http://www.youtube.com/watch?v=K_w3gcvA87I
My conclusion is that the Purolator filter has the correct mesh size to trap contaminants, but the filter capacity is too small and creates a pressure drop in the fuel line.
Nigel
0123456789012
[quote][b]
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grahamsingleton(at)btinte
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| Posted: Mon Oct 29, 2012 4:43 am Post subject: Vapour lock? Why? |
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Best one is an Andair, not cheap though. The old Mini gascolator is too small for a 914, GAS375 would be the one
Graham
From: William Daniell <wdaniell.longport(at)gmail.com>
To: europa-list(at)matronics.com
Sent: Monday, 29 October 2012, 11:31
Subject: RE: Vapour lock? Why?
I plumbed those in – following the book – but I see they are probably not the ideal.
So what’s the most common solution?
Will
From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of GRAHAM SINGLETON
Sent: 29 October 2012 05:29
To: europa-list(at)matronics.com
Subject: Re: Europa-List: Vapour lock? Why?
Nigel
another problem with those filters is that sometimes they look clean but aren't because the contamination is translucent when wet with fuel; so, more restriction.
You're right, they are too small. quite high fuel flow with a 914.
Graham
From: "nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)" <nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Monday, 29 October 2012, 10:01
Subject: Re: Vapour lock? Why?
On 31/07/2012 22:27, klinefelter.kevin(at)gmail.com (klinefelter.kevin(at)gmail.com) wrote:
.....I was chatting with Rob Seaton ( of Rotech in canada). He said he learned how too small a fuel line and/or tortured routing can cause "cavitation" at the pumps. So maybe your fuel filter(s), on the suction side of the pump,are causing cavitation in the pump(s). Maybe due to the size (restriction of flow) of the filter, even if they are clean.
........ Snip
Kevin, I think Rob Seaton may be on the money with this one.
A year or so back, I experienced a dead cut while flying a friend's 914 powered Europa on a hot day. Nifty application of fuel pump restored the noise, but once safely back on the ground, I checked the filters (all clean). This aircraft was fitted with Europa specified Purolator glass shrouded filters that allow you to see the fuel flowing. At low RPM, the filter appeared full, but as power was increased, the filter began to fill with what I thought was air. My first action was to check the pipework and security of connections - but everything seemed fine - it was definitely not drawing in air from anywhere. I then concluded that I had experienced vapour lock and left it at that.
Curiosity got the better of me and I started researching cavitation and stumbled upon this very stilted, but interesting presentation on Youtube. Take a look at the first minute from 00.20 - in particular, the glass venturi. This was exactly what I saw in the Purolator filters.
http://www.youtube.com/watch?v=K_w3gcvA87I
My conclusion is that the Purolator filter has the correct mesh size to trap contaminants, but the filter capacity is too small and creates a pressure drop in the fuel line.
Nigel
0123456789012
3
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peterz(at)zutrasoft.com
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| Posted: Mon Oct 29, 2012 4:58 am Post subject: Vapour lock? Why? |
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a second alternative: http://www.stevesaircraft.com/gascolator.php
not cheap either tho.
Cheers,
Pete
On Mon, Oct 29, 2012 at 8:40 AM, GRAHAM SINGLETON <grahamsingleton(at)btinternet.com (grahamsingleton(at)btinternet.com)> wrote:
[quote]Best one is an Andair, not cheap though. The old Mini gascolator is too small for a 914, GAS375 would be the one
Graham
From: William Daniell <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Monday, 29 October 2012, 11:31
Subject: RE: Vapour lock? Why?
I plumbed those in – following the book – but I see they are probably not the ideal.
So what’s the most common solution?
Will
From: owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: 29 October 2012 05:29
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: Vapour lock? Why?
Nigel
another problem with those filters is that sometimes they look clean but aren't because the contamination is translucent when wet with fuel; so, more restriction.
You're right, they are too small. quite high fuel flow with a 914.
Graham
From: "nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)" <nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Monday, 29 October 2012, 10:01
Subject: Re: Vapour lock? Why?
On 31/07/2012 22:27, klinefelter.kevin(at)gmail.com (klinefelter.kevin(at)gmail.com) wrote:
.....I was chatting with Rob Seaton ( of Rotech in canada). He said he learned how too small a fuel line and/or tortured routing can cause "cavitation" at the pumps. So maybe your fuel filter(s), on the suction side of the pump,are causing cavitation in the pump(s). Maybe due to the size (restriction of flow) of the filter, even if they are clean.
........ Snip
Kevin, I think Rob Seaton may be on the money with this one.
A year or so back, I experienced a dead cut while flying a friend's 914 powered Europa on a hot day. Nifty application of fuel pump restored the noise, but once safely back on the ground, I checked the filters (all clean). This aircraft was fitted with Europa specified Purolator glass shrouded filters that allow you to see the fuel flowing. At low RPM, the filter appeared full, but as power was increased, the filter began to fill with what I thought was air. My first action was to check the pipework and security of connections - but everything seemed fine - it was definitely not drawing in air from anywhere. I then concluded that I had experienced vapour lock and left it at that.
Curiosity got the better of me and I started researching cavitation and stumbled upon this very stilted, but interesting presentation on Youtube. Take a look at the first minute from 00.20 - in particular, the glass venturi. This was exactly what I saw in the Purolator filters.
http://www.youtube.com/watch?v=K_w3gcvA87I
My conclusion is that the Purolator filter has the correct mesh size to trap contaminants, but the filter capacity is too small and creates a pressure drop in the fuel line.
Nigel
012 34567 8901 2
3
4
[b]
| | - 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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ptag.dev(at)talktalk.net
Guest
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| Posted: Mon Oct 29, 2012 5:20 am Post subject: Vapour lock? Why? |
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I use two Mini Andair Gascolators one on each fuel line for my 914 and one was satisfactory when I had the early gas guzzling Jabiru 3300 and was the butt of all fuel dispensing  pump sites.
Regards to all.
Bob Harrison G-PTAG
From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of GRAHAM SINGLETON
Sent: 29 October 2012 12:40
To: europa-list(at)matronics.com
Subject: Re: Vapour lock? Why?
Best one is an Andair, not cheap though. The old Mini gascolator is too small for a 914, GAS375 would be the one
Graham
From: William Daniell <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Monday, 29 October 2012, 11:31
Subject: RE: Vapour lock? Why?
I plumbed those in – following the book – but I see they are probably not the ideal.
So what’s the most common solution?
Will
From: owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: 29 October 2012 05:29
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: Vapour lock? Why?
Nigel
another problem with those filters is that sometimes they look clean but aren't because the contamination is translucent when wet with fuel; so, more restriction.
You're right, they are too small. quite high fuel flow with a 914.
Graham
From: "nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)" <nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Monday, 29 October 2012, 10:01
Subject: Re: Vapour lock? Why?
On 31/07/2012 22:27, klinefelter.kevin(at)gmail.com (klinefelter.kevin(at)gmail.com) wrote:
.....I was chatting with Rob Seaton ( of Rotech in canada). He said he learned how too small a fuel line and/or tortured routing can cause "cavitation" at the pumps. So maybe your fuel filter(s), on the suction side of the pump,are causing cavitation in the pump(s). Maybe due to the size (restriction of flow) of the filter, even if they are clean.
........ Snip
Kevin, I think Rob Seaton may be on the money with this one.
A year or so back, I experienced a dead cut while flying a friend's 914 powered Europa on a hot day. Nifty application of fuel pump restored the noise, but once safely back on the ground, I checked the filters (all clean). This aircraft was fitted with Europa specified Purolator glass shrouded filters that allow you to see the fuel flowing. At low RPM, the filter appeared full, but as power was increased, the filter began to fill with what I thought was air. My first action was to check the pipework and security of connections - but everything seemed fine - it was definitely not drawing in air from anywhere. I then concluded that I had experienced vapour lock and left it at that.
Curiosity got the better of me and I started researching cavitation and stumbled upon this very stilted, but interesting presentation on Youtube. Take a look at the first minute from 00.20 - in particular, the glass venturi. This was exactly what I saw in the Purolator filters.
http://www.youtube.com/watch?v=K_w3gcvA87I
My conclusion is that the Purolator filter has the correct mesh size to trap contaminants, but the filter capacity is too small and creates a pressure drop in the fuel line.
Nigel
http://www.matro====================
0123456789012345
[quote][b]
| | - 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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wdaniell.longport(at)gmai
Guest
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| Posted: Mon Oct 29, 2012 6:09 am Post subject: Vapour lock? Why? |
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Mmm yes thanks. It would seem to me that the two fuel lines offer an opportunity to insert redundancy in the fuel filters.
Will
From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Bob Harrison
Sent: 29 October 2012 08:20
To: europa-list(at)matronics.com
Subject: RE: Vapour lock? Why?
I use two Mini Andair Gascolators one on each fuel line for my 914 and one was satisfactory when I had the early gas guzzling Jabiru 3300 and was the butt of all fuel dispensing pump sites.
Regards to all.
Bob Harrison G-PTAG
From: owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com] ([email][mailto:owner-europa-list-server(at)matronics.com][/email]) On Behalf Of GRAHAM SINGLETON
Sent: 29 October 2012 12:40
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: Vapour lock? Why?
Best one is an Andair, not cheap though. The old Mini gascolator is too small for a 914, GAS375 would be the one
Graham
From: William Daniell <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Monday, 29 October 2012, 11:31
Subject: RE: Vapour lock? Why?
I plumbed those in – following the book – but I see they are probably not the ideal.
So what’s the most common solution?
Will
From: owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: 29 October 2012 05:29
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: Vapour lock? Why?
Nigel
another problem with those filters is that sometimes they look clean but aren't because the contamination is translucent when wet with fuel; so, more restriction.
You're right, they are too small. quite high fuel flow with a 914.
Graham
From: "nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)" <nigel_graham(at)m-tecque.co.uk (nigel_graham(at)m-tecque.co.uk)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Monday, 29 October 2012, 10:01
Subject: Re: Vapour lock? Why?
On 31/07/2012 22:27, klinefelter.kevin(at)gmail.com (klinefelter.kevin(at)gmail.com) wrote:
.....I was chatting with Rob Seaton ( of Rotech in canada). He said he learned how too small a fuel line and/or tortured routing can cause "cavitation" at the pumps. So maybe your fuel filter(s), on the suction side of the pump,are causing cavitation in the pump(s). Maybe due to the size (restriction of flow) of the filter, even if they are clean.
........ Snip
Kevin, I think Rob Seaton may be on the money with this one.
A year or so back, I experienced a dead cut while flying a friend's 914 powered Europa on a hot day. Nifty application of fuel pump restored the noise, but once safely back on the ground, I checked the filters (all clean). This aircraft was fitted with Europa specified Purolator glass shrouded filters that allow you to see the fuel flowing. At low RPM, the filter appeared full, but as power was increased, the filter began to fill with what I thought was air. My first action was to check the pipework and security of connections - but everything seemed fine - it was definitely not drawing in air from anywhere. I then concluded that I had experienced vapour lock and left it at that.
Curiosity got the better of me and I started researching cavitation and stumbled upon this very stilted, but interesting presentation on Youtube. Take a look at the first minute from 00.20 - in particular, the glass venturi. This was exactly what I saw in the Purolator filters.
http://www.youtube.com/watch?v=K_w3gcvA87I
My conclusion is that the Purolator filter has the correct mesh size to trap contaminants, but the filter capacity is too small and creates a pressure drop in the fuel line.
Nigel
http://www.matro====================
0123456789012345678901234
[quote][b]
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budyerly(at)msn.com
Guest
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| Posted: Mon Oct 29, 2012 12:23 pm Post subject: Vapour lock? Why? |
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<?xml:namespace prefix="v" /><?xml:namespace prefix="o" /><![endif]--> Gents,
I have not had the opportunity to have cavitation or problems with fuel vaporization on my or any of my 914 engine installations.
I have had problems with the pumps pulling air from gascolators in the Europa. I do not install them for a number of reasons, primarily as the tank is lower than the gascolator (so the gascolator doesn't trap water, instead it only can trap large particles (which the tank screen should do), act as a filter), and should the seal be just a bit loose or broken, air is sucked into the fuel lines by the pump and in some cases the pump can not self prime. I have also had loose filters, and other things as below.
The main problems I have seen are:
The fuel fittings or selector valves which are too restrictive (less than 1/4 inch ID for the fuel). Avoid items of cheap quality (normally brass from China).
The Purolator fuel filters are assembled too loose and suck air by the gasket when the pump is engaged.
Note that under high flow rates over 10 GPH the Purolators do cavitate the fuel. Not so under normal operations.
The fuel filter is assembled backwards by the owner.
Gascolators installed of dubious quality/or maintained poorly, with wrench marks and dented cans from excessive force used to install or remove them. Once the seal is broken, one may not see a leak but prime is lost, especially at low fuel tank levels.
Owner uses a unique fuel line installation which goes next to the muffler, then over the top of the engine to the carb on a 912S without any fire sleeve.
Kinked fuel lines in the central tunnel unnoticed during the build.
Auto filters using cheap paper which restrict fuel flow if wet. Test Test Test non aviation filters.
Failure to install fire sleeve, instead they use thermosleeve which holds radiated heat away but has no insulation.
Vaporization also is more common when the lines are routed so as to have a bend forming a high spot in line, in a hot area of the engine compartment. This is a problem in the tail dragger Europa as the highest spot in the fuel system is the top of the engine, so a vapor bubble from heat can form easily when attempting a hot start.
The 914 has a noticeable return flow and the 912S has an orifice that allows modest flow and allows the vapor to bleed if the orifice is near the carbs and not really low in the return line at the tank. The new 912 fuel manifold seems to work well mounted up on the cross over tube in the trigear.
Fuel pumps normally take care of any heat problems in the fuel as cool fuel flows quickly through the system. However if the engine is off, fuel may not flow enough to cool the lines in a 912S that are installed directly in contact with the top of the engine. The vapor then can build up in the high spot on top of the hot engine. With the carb bowls full of fuel, the cool fuel does not flow very fast past the orifice if it installed very low. Hence the need that the orifice on the return is high up to clear the vapor.
Some suggestions are:
If one is concerned about flow, two filters in parallel, properly installed, could solve filter clogging where poor fuel quality is common.
Install 3/8 lines to slow the flow, but this means less room in tight spots and more connector step downs and more parts to buy.
Make sure you are assembling the fuel system in accordance with acceptable methods and standards and or follow the Europa install manual to the letter. After all, it works, but it is the minimum necessary to do the job.
Failure to allow for sufficient cooling air in the cowl over the carbs and fuel lines is a problem also, especially with the 912/912S. The 914 lines are at the rear and if clear of the exhaust and the fuel pump delivers proper flow, all is well.
Stay away from ethanol laced gasoline as it vaporizes very well and kills seals.
Be sure the fuel pump is of the proper size and type recommended as the system is designed for that pump.
Hot start problems in the 914 can be irritating as the intake manifold is quite warm after shutdown, as are the fuel lines and carbs. The vapor in the carbs flows into the intake plenum and manifold and leaves a super rich charge in the plenum which will delay start. Many of us crank the engine with the fuel pump off or selector off until it hits, then turn the pump/selector on to keep it running. At higher altitudes and density altitude conditions, it is much worse.
This is not a cavitation problem but pure vaporization of fuel in the intake of course.
Glad to confuse the issue.
Regards,
Bud Yerly
Tech Support
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