Beech Baron Digital Fuel Sender Retrofit Part 6

Beech Baron 58 Fuel Level Senders

CIES Baron 58 Fuel Quantity Senders

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We have some results back on the Baron 58 Senders.    There was a slight glitch as the middle left sender somehow got caught on the initial calibration.  But that was rectified easily   

The result was a fairly simple curve with no major discontinuities - Nice Job.

Even better we got a good result in the air.  

We got the middle float unstuck on the left side, it was helpful that with a frequency output graph that you could pinpoint the problem remotely like that.

After it was free, we mirrored the calibration numbers on the right side with the offset we had from the first reading and They  seem very accurate,  within a gallon of the totalizer on the JPI 960.

Tank calibration curve

We put lots of work on this aircraft... we did air conditioner, new engines, props, & avionics.    The owner has flown in it,  but we are still tweaking and breaking in the new engines for him.   

So a gallon or so off of the totalizer on a 150 gallon aircraft -  Not bad at all. 

Legacy Beechcraft Senders

All dimensions for these new senders  were captured from a legacy set of Beech Baron 58 Fuel Level senders.  As the CiES design constraints are different from the legacy senders - there are a few little tricks to getting the right geometry in the tank 

For this short flight fuel level is in green and fuel flow in blue.  You can see the effects of pitch change on fuel level on takeoff and landing. But you can also see the steady drop in fuel level over time.


This was our first multiple sender summing aircraft and we are very happy with the result. 

We were looking forward to this system in the aircraft as it represents a chance for us to utilize the capability of summing multiple senders to achieve a single digital fuel tank output.  

Every day we see that we can meet or exceed  the 0.75% most stringent TSO quality standard.  In the case of the Baron - that would be 0.66% accuracy for fuel quantity. 

Beech Baron Digital Fuel Level Sender Retrofit - Part 3

Beech Baron 58 Fuel Level Senders

We have now digitized the Baron 58 Senders.  For the Baron 58 we have gone ahead with part production for top mount senders and only needed to establish the arm lengths to complete this design.   As we produce the arms in house - this gave us the shortest time to achieving a TSO Baron Fuel Sender for our customer.

All dimensions for these new senders  were captured from a legacy set of Beech Baron Fuel Level senders.  As our design constraints are different from the legacy senders - there is a little bit to getting the right geometry in the tank 

We are looking forward to this system in the aircraft as it represents a chance for us to utilize our capability of summing multiple senders to achieve a single fuel tank output 

One of the interesting items that came up in investigation is that every legacy Outboardd bottom mount Beechcraft Baron 58 Fuel Sender has a seemingly factory grind mark on the housing and screw  - Clearance ?

Stay tuned for further updates and pictures.

Cessna Cardinal 177 - Owner Reviews

Any change, even a change for the better, is always accompanied by drawbacks and discomforts." Arnold Bennett

As expected with a new system there will be a learning curve with both the installer and the aircraft owner / pilot.  It is inevitable and AOPA E Brief provided us with the proper quote last week.  It fit our feeling so well lat week, we utilized this as a alternative heading.

So far this week all issues accounted for and happy installs going on in the field.

At present we have Greg Ridder and Dennis Del Grasso with flying Cessna 177's that have the CiES Fuel Level senders installed.  The PIREPS are good to great, both of them noting a big improvement in fuel level indication.  This may be more true of a combination of new indication and of new sending units.  

While we are pretty new with the JPI EZtrends software - we can see a definite pattern to empty with the ever-present oscillations in the fuel tank.  If you look closely at the data as the tank empties the peak to peak get larger as there is more room to slosh.   

Dennis Del Grasso: 

Very sorry to hear of all these issues.  All I can relate is that when I got into the idea of going with CIES, Scott was only making the frequency based senders.  Fuel level indication was one of the primary reasons I went with JPI (actually, ALL of the engine gauges were__)

Anyway, when I bought my JPI in FEB 2014, I told JPI the type senders I was going to install - the box came configured for it.  When I finally got them plugged in and went thru the Cal process, they have worked swimmingly well!

Mostly for Scott, but if any else would like to see it, attached is the export from my two most recent flights.  (Widen the "B" column to see Date/Time) Starting on 7/20 (outside of Phila), the tanks were filled at 25 Gal each.  Flight home about 2.5.  Went up again on 8/9  without adding any fuel and the CSV file shows the fuel remaining at the end.  Aligns pretty closely with total USED between the two flights at 25.8 (meaning 24.2 remaining according to the FuelFlow sensor and computer) while the tank gauges show 23.2 remaining.  Within a gallon!  I'll take that ANY day.

Greg Ridder :

Last Wednesday Brian installed the new right sender and since then all seems to be working well.  We have not done a new calibration since the old calibration appears to be fairly accurate.  Today I will return your old sender to you.  I will be interested in hearing what happened to the V Out circuitry since the frequency response was never affected.  BTW, I did not swap out the old resistors in the connectors - still could if you think it is advisable. I was trying not to change the calibration if possible.

I’ve made few observations since the new sender was installed.  When I got the plane back with a nearly empty right tank (gauge read 4.6 gallons), I added precisely 15 gallons at the pump and the gauge read 19+ gallons. Granted, the plane was not in flight attitude, but it was hopeful that the gauge change reconciled with the gallons added.

I have also filled each of the tanks to the 22 gallon hole in the filler with the gauge results of 26 (left) and 24 (right) on the ramp and in flight.  After flying for 1.5 hours at 7.2 gal/hour via the flow meter (estimating 10.8 gal used - I was throttled back and past lean 25°) I dipped the tanks and got a crude estimate of 15 (left) and 17 (right) - indicating 12 gal used - with gauge readings of 20.6 and 18.8 respectively - indicating 10.6 gal used. Certainly the fuel level changes match up pretty well with the gas pump and flow meter and full reads “Full”. 

Watching the chart data on the gauge shown right indicates the precision of the senders and gauge are pretty noise free and clearly shows slight sloshing of fuel in the tanks during abrupt attitude changes.  

What we don’t know yet is the absolute accuracy of an “empty” tank. Our next step is to drain each tank completely and add 2 gallons of unusable fuel.  If the numbers are close to zero (± 3 gallons?) we will placard it. If not, we will redo the calibration.  

In the discussion of precision and accuracy, I’m not sure how accurate to expect any fuel system to be if changing the plane’s attitude will change fuel level measurements.  

We are pretty conservative on keeping reserve fuel and this system already appears to be MUCH better than the old steam gauges.  Hopefully, more experience with it will bring more enlightenment.  Anyway, you now have a happy customer!  Hope the rest of the installs are going well.

Thanks again for your great customer support,

We are most proud of the customer support component, because without it we would never overcome the drawbacks and discomforts.