 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
Eugene Zimmerman
Joined: 10 Jan 2006
Posts: 392
|
 Posted: Fri May 12, 2006 5:07 pm Post subject: Redundancy.. I am not gonna repeat myself ! but I am gonna |
 |
|
Notice to all Kolb flyers.
Remember this significant date and mark your calendar.
May 12, 2007 First anniversary of the death of the Kolb List.
On May 12, 2006, at 12:59 PM, John Hauck wrote:
[quote]
---
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
 |
Ralph Hoover
Joined: 09 Jan 2006
Posts: 206
Location: Central Ohio
|
| Posted: Fri May 12, 2006 6:19 pm Post subject: Re: Redundancy.. I am not gonna repeat myself ! but I am go |
|
|
Eugene, I believe that the reason John didn't write anything was because it was 1500 and dark as night. He couldn't see his hand in front of his keyboard. I guess we're all taken aback by his utter failure to utter!
Speaking of John, I'll bet he could tell us, as many others could the reason why the only fuel check valve, working in our pressure range, in our fuel mixture (ring-a-ding fuel), that I could only locate ONE check valve and its $ 50.00 EACH!
I mean, after looking at Parker, Swaglock and 24 pages of internet under the description of "Fuel Check Valve", that was the only one and that through Spruce. Is there anything else out there? Oh, there are a few from the automotive racing community but the breakaway pressures are out of our range and there are the go carts but they don't intentionally get off the ground. there are aslo the hobby scale planes and outboard motorboaters, but again their land bound and plastic and differing in pressures. Any help out there? Or did we use up this thread?
Cheap skate Ohio Ralph
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
|
Dave Bigelow
Joined: 29 Jan 2006
Posts: 103
Location: Kamuela, Hawaii
|
| Posted: Sat May 13, 2006 1:49 am Post subject: Re: Redundancy.. I am not gonna repeat myself ! but I am go |
|
|
Ralph,
California Power Systems sells fuel system check valves for about six dollars each.
Another reason for plumbing your redundant fuel system with two pumps in parallel - if one pump shoots craps in a series installation, the remaining pump has to pull fuel throught the dead pump (and check valves). Don't be stubborn about this guys, just because you did it wrong and haven't had a problem yet. That's probably because you haven't had either pump fail yet. This is an issue that has been throughly debated over the years in aviation circles. The designers put them in parallel unless the electric pump at the fuel tank is remotely located at a distance from the engine pump.
Think about it as related to a two stroke powered Kolb. You have a pulse powered engine pump that is rated to lift fuel no more than 39 inches. You have fuel tanks that are at least 30 inches lower than the engine pump. Fail the electric pump in a series installation, and you are asking the engine pump already operating near the design limit to pull fuel through the failed pump and its two internal check valves. You are better off to forget the electric pump entirely than to plumb them in series.
If this logic is lost on you, read the Rotax installation manual. It says to plumb the pumps in parallel.
| | - The Matronics Kolb-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?Kolb-List |
|
_________________
Dave Bigelow
Kamuela, Hawaii
FS2, HKS 700E |
|
| Back to top |
|
|
Ralph Hoover
Joined: 09 Jan 2006
Posts: 206
Location: Central Ohio
|
| Posted: Sat May 13, 2006 7:31 am Post subject: Re: Redundancy.. I am not gonna repeat myself ! but I am go |
|
|
Dave, I went to CPS and was unable to find any check valves. I will call them via land line. Thanks.
As far as another poster stated in so many words: "Why add check valves as they exist in the mechanical pump and the electric pump".
There are pumps that like to suck..and they shall be called "vacuum pumps" and there are pumps that like to blow and they shall be called "pressure pumps". That said, both the mechanical pump and the electric pump are "blow" pumps. Blow pumps blow better than they suck and are best located close to the source of supply, IE. fuel tank. The mechanical pump is located where it is because that's how rotax did it. Personally, I am amazed that the little mechanical Pump does such a great job, considering what is demanded of it. But as anyone knows if they examine the thing it is the opitomy of KISS and would require something very unusual to cause it to fail. Sucking up to 39" of supply is quite a feat.Suck is hard on a blow pump but it will work. However, for the electric pump it would be best located close to the fuel tank. Knowing this means that there will be a length of exposed rubberie line leading from the pumps to the fuel use. It would be wise to locate a check valve close to the use point in redundant pumping systems because if one line developed a leak, or began sucking air it would cause the other pump to pressurize the whole of the loop. Trying to fill a hole in the dike with a finger and still suppling the engine with fuel is asking way too much!
That is where our situation came from, which created this thread. That's why our plane went down with two fuel pumps. They make a giant loop and the fuel from one can, in a parallel system, loop past the point of use and out a area of leak.
If you apply check valves close to the use point, perhaps via manifold, which is what we will use on my instructors Challenger and my Firestar, any leak from any fuel pump will not effect the other pumps feeding the two carbs on the 503. I am the biggest believer of the KISS system but simple must be applied safely. Now with a two inlet, two outlet manifold and two supply lines from two fuel pumps coming together to feed two carbs, it would take redundant fuel pump shutdowns to end the supply.
One poster stated putting a pressure gauge on the system. A manifold with four ports along one side and a port through one end would allow two check valves from two feed supplies and two discharges to two carbs as well as a small pressure 0-6 PSI.
Then the process is simple. Turn on the electric (no squeeze ball) pump, let it pressurize the system. Read the gauge. Full choke three pulls according to Rotax (for the 503 don't know about the others). Engine starts, cut back choke (actually an enricher) and allow warm-up. shut down electric, read gauge. Turn electric pump on again and "Bobs your Uncle"!
If anyone finds fault with this analogy, I will disavow any knowledge of its creator! And, unlike my previous posts, I will use the words "do not archive", rather than state that this thread will self distruct, here in Ohio Ralph!
| | - The Matronics Kolb-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?Kolb-List |
|
|
|
| Back to top |
|
|
Dave Bigelow
Joined: 29 Jan 2006
Posts: 103
Location: Kamuela, Hawaii
|
| Posted: Sat May 13, 2006 6:50 pm Post subject: Re: Redundancy.. I am not gonna repeat myself ! but I am go |
|
|
Ralph,
My CPS catalog is a couple of years old, but the plastic check valve is listed as part number 7234 for $6.95.
I must have missed your first post. Did you have a pump failure in a parallel plumbed system where the check valves in the failed pump also failed?
I have my electric pump mounted next to and level with the bottom of my fuel tanks, so it gets to be a "pressure pump". It would be best if the Mikuni pulse pump could also be mounted at that level, but the pulse line length from the crankcase is limited to 20 inches in length. I hadn't thought of it previously, but you could use a length of copper tubing for most of the run to the fuel tank with a short lenth of the normal flexible tubing at either end (total flex not to exceed 20 inches).
In my previous post, I forgot to add the fuel filter to list of restrictions that the Mikuni must "suck" through with a failed series installation.
| | - The Matronics Kolb-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?Kolb-List |
|
_________________
Dave Bigelow
Kamuela, Hawaii
FS2, HKS 700E |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
