X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from willowsprings.uwyo.edu ([129.72.10.31] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTPS id 3593217 for flyrotary@lancaironline.net; Wed, 22 Apr 2009 15:07:02 -0400 Received-SPF: none receiver=logan.com; client-ip=129.72.10.31; envelope-from=SBoese@uwyo.edu Received: from ponyexpress-ht2.uwyo.edu (ponyexpress-ht2.uwyo.edu [10.84.60.209]) by willowsprings.uwyo.edu (8.14.2/8.14.2) with ESMTP id n3MJ6Ix7022188 for ; Wed, 22 Apr 2009 13:06:20 -0600 (MDT) (envelope-from SBoese@uwyo.edu) Received: from Boesexps (172.26.4.5) by uwmail.uwyo.edu (10.84.60.199) with Microsoft SMTP Server id 8.1.358.0; Wed, 22 Apr 2009 13:06:19 -0600 From: sboese To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: fuel senders Date: Wed, 22 Apr 2009 13:06:05 -0600 Message-ID: <46B2E0848E2E427D9048E8E2DEAA6A03@gg.uwyo.edu> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0044_01C9C34B.18996780" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 ------=_NextPart_000_0044_01C9C34B.18996780 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable In my experience, the capacitive fuel level system calibrated to read = full with auto fuel with no ethanol will read about three-fourths full when = the tanks are full of AvGas. So although there is a difference between the conductivity of those two fuels, the difference is not that extreme. = The capacitance difference between either type of fuel and ethanol is HUGE, however. Although I have avoided using fuel with ethanol, I would = expect that the capacitive system would make a good ethanol detection system = and be of little value as a fuel level indicator since the indication would be = of having much more fuel than is actually there. Unless the capacitive = system is recalibrated for the particular mix of fuel containing ethanol at the time or referenced to a cell containing fuel of the same composition, = the level indications should probably be treated with a great deal of skepticism. =20 It would be valuable to get feedback from someone who has had firsthand experience with the effect of fuels containing ethanol on capacitive = sender calibration. I certainly would like to be shown to be wrong about this. =20 Wishing I wouldn't have had a choice. =20 Steve Boese =20 =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. Hughes Sent: Wednesday, April 22, 2009 11:39 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: fuel senders =20 100LL and auto fuel have different capacitance. Not sure about different blends of auto fuel. Bobby =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of n3773@comcast.net Sent: Wednesday, April 22, 2009 10:35 AM To: Rotary motors in aircraft Subject: [FlyRotary] fuel senders i wanted to comment that in the 12 years i have been flying my -6a i've noticed many people installing capacitance fuel senders. i didn't have = a choice 15 years ago. meanwhile i have read so many posts from people = having troubles with them. i have the old float/resistor type, as does my = hangar mate. we both have over 1000+ hrs on our planes and have had no = problems. we installed them, connnected the wire to the guage, done. the last = quarter tank seems to go a bit faster than the first, same as my truck. the = only fuel level problem i've had was from installing low-fuel level switches which melted, despite specs that said they were for fuel usage, and = almost popped out of the tank. but, that ocurred early on, and i realize that = i watch the fuel level like a hawk when flying. kevin [gadgets are = fun when they work right. debugging isn't. try fixing intermittent auto pilot/gps glitches for instance] ------=_NextPart_000_0044_01C9C34B.18996780 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

In my experience, the capacitive = fuel level system calibrated to read full with auto fuel with no ethanol will = read about three-fourths full when the tanks are full of AvGas.  So = although there is a difference between the conductivity of those two fuels, the = difference is not that extreme.  The capacitance difference between either type = of fuel and ethanol is HUGE, however.  Although I have avoided using fuel = with ethanol, I would expect that the capacitive system would make a good = ethanol detection system and be of little value as a fuel level indicator since = the indication would be of having much more fuel than is actually = there.  Unless the capacitive system is recalibrated for the particular mix of fuel = containing ethanol at the time or referenced to a cell containing fuel of the same composition, the level indications should probably be treated with a = great deal of skepticism.

 

It would be valuable to get = feedback from someone who has had firsthand experience with the effect of fuels = containing ethanol on capacitive sender calibration.  I certainly would like = to be shown to be wrong about this.

 

Wishing I wouldn’t have had a = choice…

 

Steve Boese

 

 

-----Original = Message-----
From: Rotary motors in = aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. Hughes
Sent: Wednesday, April = 22, 2009 11:39 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = fuel senders

 

100LL and auto = fuel have different capacitance. Not sure about different blends of auto = fuel. Bobby

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of n3773@comcast.net
Sent: Wednesday, April = 22, 2009 10:35 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] fuel = senders

i wanted to comment that in the 12 years i have been flying my -6a i've = noticed many people installing capacitance fuel senders.  i didn't have a = choice 15 years ago.  meanwhile i have read so many posts from people = having troubles with them.  i have the old float/resistor type, as does my = hangar mate.  we both have over 1000+ hrs on our planes and have had no = problems.  we installed them, connnected the wire to the guage, done. =  the last quarter tank seems to go a bit faster than the first, same as my truck.  the only fuel level problem i've had was from installing low-fuel = level switches which melted, despite specs that said they were for fuel usage, = and almost popped out of the tank.  but, that ocurred early on, and i = realize that i watch the fuel level like a hawk when flying.     kevin  [gadgets are fun when they work right.  debugging isn't. =  try fixing intermittent auto pilot/gps glitches for = instance]

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