---------------------------------------------------------- Stratus-List Digest Archive --- Total Messages Posted Tue 10/05/04: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:35 PM - Re: Stratus EA-81 Cooling (Andrew SanClemente) 2. 02:59 PM - Re: Stratus EA-81 Cooling (Hinde, Frank George (Corvallis)) ________________________________ Message 1 _____________________________________ Time: 02:35:55 PM PST US From: Andrew SanClemente Subject: RE: Stratus-List: Stratus EA-81 Cooling --> Stratus-List message posted by: Andrew SanClemente Frank, no embarrassment, I did plumb as you described - but that was also how the factory told me to do it. The first question I asked them when they described how to put the pumps was "won't that pump sucking the fuel cause vapour-lock if the wing pump fails?". They said it wouldn't and if I remember correctly he said they had theirs plumbed that way at the time. This didn't necessarily convince me but with the wing tank pump pushing I didn't worry too much. For me to have fuel starvation the following needs to happen : 1. One wing tank pump fails =09- switch tanks and pumps 2. Other wing tank pump fails - allow firewall pump to continue pumping 3. Firewall pump either fails or vapour-locks within minutes of 2 since flight will be terminated after 1 or 2. 4. I allow the flight to continue long enough for this to all transpire. I tend to doubt that a two pumps will fail within a few minutes and the third will immediately cause vapour-lock before I could get down. If I am being naive feel free to say so, rather have my feelings hurt than kill myself.Feel free to let me know your thoughts and recommendations, again, free exchange of ideas and knowledge is a good thing and I won't be upset if you say I'm being a moron - just do it nicely ;) Thanks! Andy On Mon, 4 Oct 2004 11:43:24 -0700, Hinde, Frank George (Corvallis) wrote: >--> Stratus-List message posted by: "Hinde, Frank George >(Corvallis)" > >Andy, > >If you have don what I think you have, then I do not like your fuel >system design. > >This is what I THINK you did... > >You put a single pump that draws from both tanks using a selector >valve >perhaps? You have a second pump on the firewall that is plumbed in >series with the wing tanks. > >I say I think you did this because series plumbing of two pumps is >the >only way your pressure will double like that. > >Is this the case?...If so I think you should replumb your system as >you >are asking for vapour lock....with deadly consequences...Admittedly >the >the wing tank pump will have to fail for this to happen but its not >ideal by any stretch. > >Let me know what you did and we can talk some more. > >I will post this to the group, not to embarrass you, just simply to >get >the word out. > >Frank > > Frank, no embarrassment, I did plumb as you described - but that was also how the factory told me to do it. The first question I asked them when they described how to put the pumps was won't that pump sucking the fuel cause vapour-lock if the wing pump fails?. They said it wouldn't and if I remember correctly he said they had theirs plumbed that way at the time. This didn't necessarily convince me but with the wing tank pump pushing I didn't worry too much. For me to have fuel starvation the following needs to happen : 1. One wing tank pump fails - switch tanks and pumps 2. Other wing tank pump fails - allow firewall pump to continue pumping 3. Firewall pump either fails or vapour-locks within minutes of 2 since flight will be terminated after 1 or 2. 4. I allow the flight to continue long enough for this to all transpire. I tend to doubt that a two pumps will fail within a few minutes and the third will immediately cause vapour-lock before I could get down. If I am being naive feel free to say so, rather have my feelings hurt than kill myself.Feel free to let me know your thoughts and recommendations, again, free exchange of ideas and knowledge is a good thing and I won't be upset if you say I'm being a moron - just do it nicely ;) Thanks! Andy On Mon, 4 Oct 2004 11:43:24 -0700, Hinde, Frank George (Corvallis) wrote: --=A0Stratus-List message posted by: Hinde, Frank George (Corvallis) frank.hinde@hp.com Andy, If you have don what I think you have, then I do not like your fuel system design. This is what I THINK you did... You put a single pump that draws from both tanks using a selector valve perhaps? You have a second pump on the firewall that is plumbed in series with the wing tanks. I say I think you did this because series plumbing of two pumps is the only way your pressure will double like that. Is this the case?...If so I think you should replumb your system as you are asking for vapour lock....with deadly consequences...Admittedly the the wing tank pump will have to fail for this to happen but its not ideal by any stretch. Let me know what you did and we can talk some more. I will post this to the group, not to embarrass you, just simply to get the word out. Frank ________________________________ Message 2 _____________________________________ Time: 02:59:35 PM PST US Subject: RE: Stratus-List: Stratus EA-81 Cooling From: "Hinde, Frank George (Corvallis)" --> Stratus-List message posted by: "Hinde, Frank George (Corvallis)" Actually for some reason I thought you only had wing tanks...probably been so long since I been flying with wing tanks only that I complety forgot about the header tank. Secondly I had assumed from your description that you only had two pumps...One on the firewall and one for both wing tanks. If you have a header the problem goes away because there is always positive head over the firewall pump. If you have THREE pumps (one at the outlet of each tank and one on the firewall) and no header tank the problem also goes away...Except that the firewall pump is a third level of protection (and designing to this level is overkill) and the fuel pressure will go too high when two or three pumps are run. Personally I would remove the firewall pump if you don't have the header. The important thing here is to NOT suck on the fuel and have a redundant pump that will also not suck on the fuel.....One pump at the outlet of each tank is fine. Also make sure each pump is fed from a separate electrical source (I have two electrically isolated batteries, one ignition and one pump fed from each battery) Hope that helps Frank -----Original Message----- From: owner-stratus-list-server@matronics.com [mailto:owner-stratus-list-server@matronics.com] On Behalf Of Andrew SanClemente Subject: RE: Stratus-List: Stratus EA-81 Cooling --> Stratus-List message posted by: Andrew SanClemente --> Frank, no embarrassment, I did plumb as you described - but that was also how the factory told me to do it. The first question I asked them when they described how to put the pumps was "won't that pump sucking the fuel cause vapour-lock if the wing pump fails?". They said it wouldn't and if I remember correctly he said they had theirs plumbed that way at the time. This didn't necessarily convince me but with the wing tank pump pushing I didn't worry too much. For me to have fuel starvation the following needs to happen : 1. One wing tank pump fails =09- switch tanks and pumps 2. Other wing tank pump fails - allow firewall pump to continue pumping 3. Firewall pump either fails or vapour-locks within minutes of 2 since flight will be terminated after 1 or 2. 4. I allow the flight to continue long enough for this to all transpire. I tend to doubt that a two pumps will fail within a few minutes and the third will immediately cause vapour-lock before I could get down. If I am being naive feel free to say so, rather have my feelings hurt than kill myself.Feel free to let me know your thoughts and recommendations, again, free exchange of ideas and knowledge is a good thing and I won't be upset if you say I'm being a moron - just do it nicely ;) Thanks! Andy On Mon, 4 Oct 2004 11:43:24 -0700, Hinde, Frank George (Corvallis) wrote: >--> Stratus-List message posted by: "Hinde, Frank George >(Corvallis)" > >Andy, > >If you have don what I think you have, then I do not like your fuel >system design. > >This is what I THINK you did... > >You put a single pump that draws from both tanks using a selector valve >perhaps? You have a second pump on the firewall that is plumbed in >series with the wing tanks. > >I say I think you did this because series plumbing of two pumps is the >only way your pressure will double like that. > >Is this the case?...If so I think you should replumb your system as you >are asking for vapour lock....with deadly consequences...Admittedly >the >the wing tank pump will have to fail for this to happen but its not >ideal by any stretch. > >Let me know what you did and we can talk some more. > >I will post this to the group, not to embarrass you, just simply to get >the word out. > >Frank > > Frank, no embarrassment, I did plumb as you described - but that was also how the factory told me to do it. The first question I asked them when they described how to put the pumps was won't that pump sucking the fuel cause vapour-lock if the wing pump fails?. They said it wouldn't and if I remember correctly he said they had theirs plumbed that way at the time. This didn't necessarily convince me but with the wing tank pump pushing I didn't worry too much. For me to have fuel starvation the following needs to happen : 1. One wing tank pump fails - switch tanks and pumps 2. Other wing tank pump fails - allow firewall pump to continue pumping 3. Firewall pump either fails or vapour-locks within minutes of 2 since flight will be terminated after 1 or 2. 4. I allow the flight to continue long enough for this to all transpire. I tend to doubt that a two pumps will fail within a few minutes and the third will immediately cause vapour-lock before I could get down. If I am being naive feel free to say so, rather have my feelings hurt than kill myself.Feel free to let me know your thoughts and recommendations, again, free exchange of ideas and knowledge is a good thing and I won't be upset if you say I'm being a moron - just do it nicely ;) Thanks! Andy On Mon, 4 Oct 2004 11:43:24 -0700, Hinde, Frank George (Corvallis) wrote: --=A0Stratus-List message posted by: Hinde, Frank George (Corvallis) frank.hinde@hp.com Andy, If you have don what I think you have, then I do not like your fuel system design. This is what I THINK you did... You put a single pump that draws from both tanks using a selector valve perhaps? You have a second pump on the firewall that is plumbed in series with the wing tanks. I say I think you did this because series plumbing of two pumps is the only way your pressure will double like that. Is this the case?...If so I think you should replumb your system as you are asking for vapour lock....with deadly consequences...Admittedly the the wing tank pump will have to fail for this to happen but its not ideal by any stretch. Let me know what you did and we can talk some more. I will post this to the group, not to embarrass you, just simply to get the word out. 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