X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-pd0-f179.google.com ([209.85.192.179] verified) by logan.com (CommuniGate Pro SMTP 6.0.10) with ESMTPS id 7253556 for flyrotary@lancaironline.net; Tue, 04 Nov 2014 11:01:08 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.192.179; envelope-from=ceengland7@gmail.com Received: by mail-pd0-f179.google.com with SMTP id g10so13963908pdj.10 for ; Tue, 04 Nov 2014 08:00:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type; bh=nIk9q1HXTVsHLGA4M7ckz40ABwE28nt+QhthGGU0XWA=; b=glgXGHWj76mJr8loSoExwafr1cmCAg9Dfp7lkQT+/Kym97KIEDnDLvEJ32UfzEPcih JmA6wGDTKEbWJ+LT5fqKOu7y5v0ezPEK5QkzTPlbHzxwT39GCurL8e/QlU9Gb+Iz818G JHFXb++0GGGakrxmXKDxKbbMg5neLoqh0iIQdu7GXCs5r2f87OfNW+zBSuBQeQGdx/ds etFw6VjKSFj8H/dZ8TQ1bbTRODA7CpHThTT5y/3ZqsXhWINxHirtaJi+r85XCPUfiQJ0 Ed9eQqDPgJXc1WKIhIRm8wfKBfGNy7kqpTlLpDc0W5QzbQkRHluJRvXZh3E1s1ndYPW7 ZQ6A== X-Received: by 10.70.64.231 with SMTP id r7mr51131868pds.42.1415116834947; Tue, 04 Nov 2014 08:00:34 -0800 (PST) Return-Path: Received: from ?IPv6:2602:306:25fb:99:44fe:a0e0:8dd0:4d4e? ([2602:306:25fb:99:44fe:a0e0:8dd0:4d4e]) by mx.google.com with ESMTPSA id np11sm722483pdb.78.2014.11.04.08.00.32 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 04 Nov 2014 08:00:34 -0800 (PST) Message-ID: <5458F8A4.6050408@gmail.com> Date: Tue, 04 Nov 2014 10:02:44 -0600 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: SPAM-LOW: [FlyRotary] Re: Fw: Rotary Engine & Fuel Valves References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------030209060702020607030500" This is a multi-part message in MIME format. --------------030209060702020607030500 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit I agree with Bill. I'm not aware of any certified low wing a/c with a 'both' position on their fuel selector, and all the homebuilt kit makers that I'm aware of specifically say to never operate the plane with a fuel selector on 'both'. Unporting can happen at any time. If it happens close to the ground, you can run out of time even if the pump will self-prime. Charlie On 11/4/2014 9:35 AM, William Schertz wrote: > A cautionary note with this system. An early builder of the KIS-2place > low wing plane substituted a Cessna L-R-Both_off valve for the L-R-off > valve supplied with the kit. He did this because he felt it would be > safer for his less experienced son who would not have to remember to > switch tanks. During the test flight portion of flying off the hours, > he discovered that while on both, one tank ran dry – he switched to > the tank with fuel and found that it would not feed and he made a > engine out crosswind landing on the nearest runway, ran off the runway > and damaged the wing, had to rebuild it. > Apparently the pump lost its prime and would not feed from the full tank. > Bill Schertz > *From:* Al Wick > *Sent:* Tuesday, November 04, 2014 8:16 AM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: SPAM-LOW: [FlyRotary] Re: Fw: Rotary Engine > & Fuel Valves > What an excellent analysis. Assume failures others have had will > happen to you, design accordingly. > -Al Wick > > -------- Original message -------- > From: Thomas Mann > Date:11/04/2014 6:12 AM (GMT-08:00) > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: SPAM-LOW: [FlyRotary] Re: Fw: Rotary Engine & > Fuel Valves > If you are going to use a common feed system, the best way to do it is > via a Left/Right/Both/Off type selector valve. > With that system if you are running on “Both” and you have an uneven > feed, it’s easy to resolve, just switch to the fullest tank. > More important is the missing fuel cap scenario. Most aircraft have a > vent tube that is situated is such a manner that it works like a > little ram air scoop to force air into the vent system. > Most pilots think that when you loose a fuel tank cap, the fuel is > sucked out ….. not so. What happens is the fuel tank without the cap > fails to pressurize the way the fuel tank with the cap does. As such > (in a “T” or common feed system) the higher pressure tank begins to > push the fuel into the lower pressure tank. Of course with no fuel > cap, the low pressure tank overfills an the excess fuel goes overboard. > Once the last of the fuel passes the common junction, you have fuel > starvation and one full tank of fuel that you cannot access. In a > system with the described selector valve, selecting between individual > tanks would make this a non-event. If you were running on “Both” you > could empty the high pressure side but once it started sputtering you > could be back in business by switching to the full tank (with no cap) > and would still be able to access that fuel. > Just something to consider. I just picked up n airplane this past > spring that had a common sump system. The first thing I did was > convert it to the system I described above. The owner said it didn’t > feed from the wing tanks evenly and he would have to land sometimes to > let the fuel settle out to an even level then press on. This selector > valve setup allows you to correct the issue in the air. > T Mann > Sent from Windows Mail --------------030209060702020607030500 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit
I agree with Bill.

I'm not aware of any certified low wing a/c with a 'both' position on their fuel selector, and all the homebuilt kit makers that I'm aware of specifically say to never operate the plane with a fuel selector on 'both'. Unporting can happen at any time. If it happens close to the ground, you can run out of time even if the pump will self-prime.

Charlie

On 11/4/2014 9:35 AM, William Schertz wrote:
A cautionary note with this system. An early builder of the KIS-2place low wing plane substituted a Cessna L-R-Both_off valve for the L-R-off valve supplied with the kit. He did this because he felt it would be safer for his less experienced son who would not have to remember to switch tanks. During the test flight portion of flying off the hours, he discovered that while on both, one tank ran dry – he switched to the tank with fuel and found that it would not feed and he made a engine out crosswind landing on the nearest runway, ran off the runway and damaged the wing, had to rebuild it.
 
Apparently the pump lost its prime and would not feed from the full tank.
Bill Schertz
 
From: Al Wick
Sent: Tuesday, November 04, 2014 8:16 AM
Subject: [FlyRotary] Re: SPAM-LOW: [FlyRotary] Re: Fw: Rotary Engine & Fuel Valves
 
What an excellent analysis. Assume failures others have had will happen to you, design accordingly.
 
 
-Al Wick

-------- Original message --------
From: Thomas Mann
Date:11/04/2014 6:12 AM (GMT-08:00)
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: SPAM-LOW: [FlyRotary] Re: Fw: Rotary Engine & Fuel Valves
 
If you are going to use a common feed system, the best way to do it is via a Left/Right/Both/Off type selector valve.
With that system if you are running on “Both” and you have an uneven feed, it’s easy to resolve, just switch to the fullest tank.
 
More important is the missing fuel cap scenario. Most aircraft have a vent tube that is situated is such a manner that it works like a little ram air scoop to force air into the vent system.
 
Most pilots think that when you loose a fuel tank cap, the fuel is sucked out ….. not so. What happens is the fuel tank without the cap fails to pressurize the way the fuel tank with the cap does. As such (in a “T” or common feed system) the higher pressure tank begins to push the fuel into the lower pressure tank. Of course with no fuel cap, the low pressure tank overfills an the excess fuel goes overboard.
 
Once the last of the fuel passes the common junction, you have fuel starvation and one full tank of fuel that you cannot access. In a system with the described selector valve, selecting between individual tanks would make this a non-event. If you were running on “Both” you could empty the high pressure side but once it started sputtering you could be back in business by switching to the full tank (with no cap) and would still be able to access that fuel.
 
Just something to consider. I just picked up n airplane this past spring that had a common sump system. The first thing I did was convert it to the system I described above. The owner said it didn’t feed from the wing tanks evenly and he would have to land sometimes to let the fuel settle out to an even level then press on. This selector valve setup allows you to correct the issue in the air.
 
T Mann
 
Sent from Windows Mail
 
 

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