AeroElectric-List Digest Archive

Wed 06/07/06


Total Messages Posted: 6



Today's Message Index:
----------------------
 
     1. 04:52 AM - Re: princeton capactive fuel probe  (Jim Butcher)
     2. 07:05 PM - epanelbuilder.com difficulties (Fiveonepw@aol.com)
     3. 07:59 PM - Re: Re: princeton capactive fuel probe (Richard E. Tasker)
     4. 08:16 PM - Re: -- Baluns  (Noel Loveys)
     5. 08:16 PM - Re: princeton capactive fuel probe (Noel Loveys)
     6. 08:31 PM - Re: epanelbuilder.com difficulties (John Schroeder)
 
 
 


Message 1


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    Time: 04:52:10 AM PST US
    From: "Jim Butcher" <europa@triton.net>
    Subject: Re: princeton capactive fuel probe
    --> AeroElectric-List message posted by: "Jim Butcher" <europa@triton.net> We fitted a Princeton capactive probe in our Europa. We are using premiun auto gas. What we have learned is that ethanol changes the dielectric value a lot which results in gross errors (inaccurate readings). The amount of ethanol added by the gasoline distributors seems to vary depending on season of the year (we are in Michigan). Other Europa owners have noted that aviation gas (100 LL) and auto fuel have different dielectric values which results in about a 5% error in reading. What some have done instead of using a capactive probe, is to fit a gage pressure sensor at the bottom of the tank (or in a line coming from the bottom) and measure the weight of fuel which is more constant and isn't affected by the addition of ethanol. See Level Master at www.msiusa.com or http://catalog.sensing.honeywell.com and look for 26PCAFB6G for examples of sensors. Jim & Heather Butcher Europa XS N241BW


    Message 2


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    Time: 07:05:59 PM PST US
    From: Fiveonepw@aol.com
    Subject: epanelbuilder.com difficulties
    Howdy all- Has anyone had any success using this website: http://www.epanelbuilder.com/ I've registered, downloaded the required Macromedia app, supposedly started a project, couldn't get any instruments to show in the library (after struggling for 15 minutes to get a panel template to show) and then couldn't open that project next time I tried, and generally run into more problems than any app (out of hundreds- this stuff is NOT new to me!) I've ever tried to use before. Then tried to get assistance, been issued "tickets" (what ever happened to customer support via e-mail, fer chrissake!!) and am genuinely frustrated and annoyed after over 3 hours for 2 days of trying to accomplish anything. Must not be holding my left foot in the correct position or the moon is out of phase. Anyone else with horror/success stories with this? Suggestions for alternatives welcome- maybe I'll just go back to AutoCAD and my previous excellent panel cutting service.... Mark Phillips N51PW do not archive


    Message 3


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    Time: 07:59:13 PM PST US
    From: "Richard E. Tasker" <retasker@optonline.net>
    Subject: Re: princeton capactive fuel probe
    --> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net> I would highly NOT recommend the MSI part. The pressure fitting is made of PVC! Not a good thing to expose to gasoline unless you want a large hole in the bottom of your gas tank (where the sensor was)! The Honeywell part might work, but the gasoline would definitely affect some of the internal materials - causing inaccuracies if you are lucky or failure if you are not. While the idea is a good one, I would not install either of these parts on my airplane! Dick Tasker Jim Butcher wrote: <snip> >Other Europa owners have noted that aviation gas (100 LL) and auto fuel have >different dielectric values which results in about a 5% error in reading. >What some have done instead of using a capactive probe, is to fit a gage >pressure sensor at the bottom of the tank (or in a line coming from the >bottom) and measure the weight of fuel which is more constant and isn't >affected by the addition of ethanol. See Level Master at www.msiusa.com or >http://catalog.sensing.honeywell.com and look for 26PCAFB6G for examples of >sensors. > >Jim & Heather Butcher >Europa XS N241BW > > > > > > > > > -- Please Note: No trees were destroyed in the sending of this message. We do concede, however, that a significant number of electrons may have been temporarily inconvenienced. --


    Message 4


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    Time: 08:16:40 PM PST US
    From: "Noel Loveys" <noelloveys@yahoo.ca>
    Subject: -- Baluns
    --> AeroElectric-List message posted by: "Noel Loveys" <noelloveys@yahoo.ca> Balun.... Balanced to unbalanced.. Coax is unbalanced line the dipole antennas are in fact balanced antennas. The balun is a device which allows you to use an unbalanced line to feed a balanced antenna. Will your dipole work better with a balun ???? The only thing I could say is try it. You won't need a very big or heavy balun because the transmit power on an aircraft is usually pretty low.... On the receive side of things I doubt you will see any difference at all. Don't forget that a horizontal dipole antenna has a directional factor to it. This is the reason that most com radios have vertical antennas. We used 300/F(mhz) to give an answer in metric.... A little easier to remember. Noel > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On > Behalf Of Hopperdhh@aol.com > Sent: Tuesday, June 06, 2006 9:14 AM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: -- Baluns > > > --> AeroElectric-List message posted by: Hopperdhh@aol.com > > > Bob and others on the list, > > It is my understanding that the purpose of the balun is > mainly to prevent > the feed line from distorting the pattern of the antenna. > That is, to keep the > antenna purely horizontal so that it will be less receptive > to reflections > from mountains and large buildings for example. When waves > reflect off of > things they tend to lose the original polarity (horizontal or > vertical). The > balun isolates the antenna from the feed line and makes it > more like a pure > horizontal dipole. > > Having said all of that, I have a dipole attached to the > canopy of my RV-7A > with NO balun (because I didn't have one handy) and it > appears to work just > fine. Perhaps it would work even better with the balun! > > By the way, I experimented with the length using my MFJ-259B Antenna > Analyzer looking for the lowest SWR across the 108 to 118 MHz > nav band. Start with > the antenna long, say cut for 100 MHz and trim to move the > SWR higher in > frequency. The reason it is necessary to experiment here is > that the antenna is > not in the clear, and also it is not running straight. > > The length of an ideal dipole antenna (in feet) is approximately > 468/Freq(MHz) from any of the ARRL Handbooks. > > Hope this helps, > > Dan Hopper K9WEK > > > In a message dated 6/4/2006 3:48:34 P.M. Eastern Daylight Time, > nuckollsr@cox.net writes: > http://n-lemma.com/calcs/dipole/balun.htm > > http://en.wikipedia.org/wiki/Dipole_antenna > > We used to wire our VOR cat-whiskers on the > single engined Cessnas with a balun back in the > 60' but gave it up after a series of experiments > showed no perceivable difference between antennas > with baluns and antennas that simply attached > the center conductor to one leg of the dipole > and coax braid to the other leg. > > Some folks believe in slipping ferrite toroidal > cores over the coax like this figure from the > AeroElectric Connection: > > http://www.aeroelectric.com/Pictures/Antenna/Dipole_Antenna.pdf > > However, subsequent to publishing that figure I've > done some testing in the lab and found that the > ferrite cores offer no observable improvement in > VOR receiver or GS receiver performance by their > use. > > Therefore, it's my recommendation that you forgo > the use of either balun or ferrite cores and simply > attach the legs of your dipole to the center conductor > and shield of the coax. > > Bob . . . > > > > > > > > > > > > > > > >


    Message 5


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    Time: 08:16:40 PM PST US
    From: "Noel Loveys" <noelloveys@yahoo.ca>
    Subject: princeton capactive fuel probe
    --> AeroElectric-List message posted by: "Noel Loveys" <noelloveys@yahoo.ca> Capacitive fuel gauges also require a "wet probe" This is a small probe that is at the bottom of your tank and is always covered with fuel. It actually does tow jobs ... First it allows the fuel gauge to be accurate when the tanks are close to empty and it will do a good job as a water detector. A little water on the wet probe will lower the capacitance to a point where a logic circuit can turn on a "Water in the gas" light. Most tanks will have more than one probe in them. Most transport cat planes will have several in each tank so the fuel quantity will be pretty accurate even when the plane is in a turn, climbing or descending. The probes themselves are not usually uniform in shape or diameter. These odd shapes are another way of correcting the gauges for the shape of the fuel tanks. Sound confusing??? It is a bit. Noel > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On > Behalf Of bakerocb@cox.net > Sent: Tuesday, June 06, 2006 9:38 AM > To: aeroelectric-list@matronics.com; czechsix@juno.com > Subject: AeroElectric-List: princeton capactive fuel probe > > > --> AeroElectric-List message posted by: <bakerocb@cox.net> > > > Responding to an AeroElectric-List message previously posted > by: Mark E > Navratil <czechsix@juno.com> > > 6/6/2006 > > Hello Mark, You wrote: > > <<...... skip...... My only complaint--and it's a minor > one--is that with > the tanks full, the > reading from the senders varies by about a gallon. You can > program the > EIS to show whatever quantity you want when the sender is at the full > level...I measured about 11 gals in my tank when the fuel is > at the top of > the > sender so that's what I programmed into the EIS. But the > actual reading > after > refueling is anywhere from 10.0 to 10.9, and it varies from > day to day. > I didn't expect capacitive probes to wander in their readings > like this. > Anyway, the important part is that they do seem to read > accurately when > near empty.......skip....... --Mark Navratil>> > > I am reluctant to dip my toe into any electrical waters, but my > understanding is that the capacitance probes measure the changing > capacitance between the center rod and the outer tube of the > probe as the > level of fuel changes inside the tube. Fuel and air have different > capacitive characteristics. Through electrical magic the > system displays > this capacitance as fuel quantity. > > But also the density of fuel can change with changing > temperature and this > changing density can change the capacitance characteristics > of the fuel. So > with exactly the same amount of fuel in your tank on two > different occasion > you could read different fuel quantity depending upon the temperature > difference between those two occasions. > > This could explain the variations in your fuel quantity readings. > > OC > > > > > > > > > > > > > >


    Message 6


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    Time: 08:31:03 PM PST US
    Subject: Re: epanelbuilder.com difficulties
    From: "John Schroeder" <jschroeder@perigee.net>
    --> AeroElectric-List message posted by: "John Schroeder" <jschroeder@perigee.net> On Wed, 7 Jun 2006 21:57:38 EDT, <Fiveonepw@aol.com> wrote: > Suggestions for alternatives welcome- maybe I'll just go back to AutoCAD > and my previous excellent panel cutting service.... Mark - Are you pining again to build another panel? If you know AutoCAD like I think you know it, why try something new? :-)) How is it going with the flying? Cheers, John --




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