EDM 900 with Monroy Tanks

[201er]

19 minutes ago, PTK said:

Actually Mike, if I may humbly correct you, it has to do with the volumes in each tank and the size of the conduit from aux to main.

The dihedral enables the aux to gravity feed the main. The rate at which this happens has to do with volumes in each tank and varies accordingly.

Right. But it all depends on how much higher the outboard fuel is than the inboard fuel.

[glenv6]

On ‎2‎/‎24‎/‎2016 at 2:49 PM, 201er said:

Fuel flow and time end up being the best way to measure fuel with Monroy tanks. And the fact that you've got so much of it that you probably won't use it all by the time you get anywhere you want to go.

I have flown my 201 between Texas and California, and Texas and New York many times in the last year, so I really have this technique down.  My seat of the pants calcs are normally good to within 1-2 gallons.  I hate to let a feature go to waste on a unit like the EDM900.  I have visions of the 900 interface to the 430W showing current fuel stats for each leg. Oh well, looks like I have to continue to wing it.

[StevenL757]

On February 24, 2016 at 3:26 PM, glenv6 said:

I haven't received a quote yet, I am expecting to see it any day now....

Including installation and calibration for CIES digital transmitters, plan 4 days.  Their website also has fuel sender pricing listed now for various aircraft types including Mooneys.

From their home page, choose menu items "Applications" --> "Aircraft" --> "Aircraft Kit Pricing"

[StevenL757]

23 hours ago, carusoam said:

Them funky digital sensors have an interesting level of flexibility with them.  Setting them up may require adding a gallon at a time for ultimate accuracy.  The website has good reading of how it works.

As for the analog wing mounted gauges.  They are independent of the fuel instrumentation on the panel.  They are calibrated for accuracy on level ground.  Nobody is going to give them up without a fight.

Some Mooneys use one float sensor per tank, like my C had.  The O has two sensors per tank to capture the uphill nature of the 100+ gallon tank.

Correct to all three.  Spending time on proper calibration is critical to the accuracy, given they are accurate to within about 1%.  The wing gauges are indeed independent, and are only accurate on the ground, not in flight.

[glenv6]

8 hours ago, StevenL757 said:

Correct to all three.  Spending time on proper calibration is critical to the accuracy, given they are accurate to within about 1%.  The wing gauges are indeed independent, and are only accurate on the ground, not in flight.

I believe you on the accuracy of the wing gauges, but in practice I haven't found there to be much difference between the wing gauge readings on the ground vs in the air....  On another note, calibrating the 900 is going to drive my guy nuts.  I can't wait!  LOL.

[glenv6]

Hi List - I am filling out the JPI order form and have a couple of questions I hope you can help with....

First, are the fuel gauges switched?  I think the answer is an obvious "YES" (they go on and off with the master switch), but wanted to be sure I am reading the question correctly.

Next, how many fuel level sending units are there?  My Mooney is an '82 M20J, which I believe has 2 sending units per tank, but the question says senders in series count at 1, so, are the 2 senders in each tank (if there are 2 senders in each tank) in series?

Thanks in advance for your help!!!

[DonMuncy]

Those with 2 senders are connected in series. So your fuel level for that tank is the average between the two senders.

[BobAustin]

I  have a JPI 850 and can set in 92 gal with all 4 tanks (85 201/Missile/Monroy) prior to my usual 650 mile trip.  I use about 60 gal leaving 32 gal or so... which I note the 32 gal remaining on the JPI 850 and verify with the expected 16 gal/side reading on the main gauges.

Has worked for dozens of trips.

[glenv6]

3 hours ago, DonMuncy said:

Those with 2 senders are connected in series. So your fuel level for that tank is the average between the two senders.

Okay, thank you!....  Now I just look in one main and saw only one sender, so I'm not really sure how many senders I have.  Any idea if an '82 M20J should have two senders/side?  Is the number of senders different by model?

[DonMuncy]

I'm almost certain all the newer planes (at least all from J's forward, and probably long before that) have two per tank.

[carusoam]

See if this makes sense...

Summation of what I learned here.

(1) Modern Mooneys have two analog floats per tank.

(2) Standard tanks and extended tanks have one fuel filler/cap.  (Some Ks have two)

(3) When the tank is filled to the top of the fill hole, gravity provides for one level top surface/air interface.

(4) closer to the wing root, fuel will be at the wing's top skin.

(5) closer to the wing tip, fuel will have an air interface where the dihedral brings the wing skin up hill.

(6) no matter how much you fill the tank, the vent doesn't leak fuel like a small dihedral C152.

(7) The tank extension drains proportionally to the rest of the tank.  The top surface falls at the same rate throughout the tank during level coordinated flight.

(8) having two analog floats (wired in series) is an electronic average and an approximation of what is in the tank.

(9) there are limitations to the accuracy as the inner float is going to bump into the wing skin.

(10) another limitation is that the outer float bottoms out first.

(11) the overall shape of the tank is nearly a parallelogram box shape with curved top and bottom surfaces. This is important to the non-digital fuel level system.  The aft wall of the tank may not be parallel to the front wall. The bottom skin is probably not flat and with the AOA it won't be parallel to the gravity produced top surface of the fuel.

(12) when installed properly, fuel flows between the original tank and it's extension.

(13) The advantage of the fully digital fuel level system is that it handles specific geometric variations of the 'nearly parallelogram box’.  When the fuel level sensors are calibrated, the two digital sensors can associate the level they measure with the exact volume that has been put in the tank.  It is not perfect as the volume will change slightly with a change of temperature.

(14) the modern floats also have a better range than the older ones.  They go closer to the top skin when full and closer to the bottom skin when going empty.

(15) To get real useable information from the digital floats, you would want to read the fuel volume from a digital screen that can read individual gallons.  I'm sure they will give values in tenths of gallons, but that probably gets lost in the significant figures discussion.

16) The wing mounted gauges may be accurate, but they are calibrated in five gallon increments.

17) The panel mounted analog gauges are similar in terms of needle display in front of a few lines. Missing both precision and accuracy.

18) digital sensors with digital displays can be more accurate and more precise and add value to the Mooney's imperfect geometry tanks.

19) modern sensors and displays cost money, no two pilots will perceive the value of these systems the same.

20) For comparison...My M20C had one analog float per tank and no FF gauge and no wing mounted fuel level display. A well calibrated stick made for a good method of partial filling the tank. The vent is a bottom mounted overflow tube in the middle of the tank(?).

21) Also, Don't forget the annunciator panel's low level indicators will not operate unless the test light has been pressed.  Some annunciators are calibrated with such a low level, they don't give enough warning to do very much about the warning... Check your POH for details....

These are the observations of a PP.  Expect that some mistakes have been made in this writing.  Let me know if you find any...

Check with your suppliers of tanks, floats and displays to determine what is best for your situation.

Best regards,

-a-

[glenv6]

11 hours ago, carusoam said:

See if this makes sense...

Summation of what I learned here.

(1) Modern Mooneys have two analog floats per tank.

(2) Standard tanks and extended tanks have one fuel filler/cap.  (Some Ks have two)

(3) When the tank is filled to the top of the fill hole, gravity provides for one level top surface/air interface.

(4) closer to the wing root, fuel will be at the wing's top skin.

(5) closer to the wing tip, fuel will have an air interface where the dihedral brings the wing skin up hill.

(6) no matter how much you fill the tank, the vent doesn't leak fuel like a small dihedral C152.

(7) The tank extension drains proportionally to the rest of the tank.  The top surface falls at the same rate throughout the tank during level coordinated flight.

(8) having two analog floats (wired in series) is an electronic average and an approximation of what is in the tank.

(9) there are limitations to the accuracy as the inner float is going to bump into the wing skin.

(10) another limitation is that the outer float bottoms out first.

(11) the overall shape of the tank is nearly a parallelogram box shape with curved top and bottom surfaces. This is important to the non-digital fuel level system.  The aft wall of the tank may not be parallel to the front wall. The bottom skin is probably not flat and with the AOA it won't be parallel to the gravity produced top surface of the fuel.

(12) when installed properly, fuel flows between the original tank and it's extension.

(13) The advantage of the fully digital fuel level system is that it handles specific geometric variations of the 'nearly parallelogram box’.  When the fuel level sensors are calibrated, the two digital sensors can associate the level they measure with the exact volume that has been put in the tank.  It is not perfect as the volume will change slightly with a change of temperature.

(14) the modern floats also have a better range than the older ones.  They go closer to the top skin when full and closer to the bottom skin when going empty.

(15) To get real useable information from the digital floats, you would want to read the fuel volume from a digital screen that can read individual gallons.  I'm sure they will give values in tenths of gallons, but that probably gets lost in the significant figures discussion.

16) The wing mounted gauges may be accurate, but they are calibrated in five gallon increments.

17) The panel mounted analog gauges are similar in terms of needle display in front of a few lines. Missing both precision and accuracy.

18) digital sensors with digital displays can be more accurate and more precise and add value to the Mooney's imperfect geometry tanks.

19) modern sensors and displays cost money, no two pilots will perceive the value of these systems the same.

20) For comparison...My M20C had one analog float per tank and no FF gauge and no wing mounted fuel level display. A well calibrated stick made for a good method of partial filling the tank. The vent is a bottom mounted overflow tube in the middle of the tank(?).

21) Also, Don't forget the annunciator panel's low level indicators will not operate unless the test light has been pressed.  Some annunciators are calibrated with such a low level, they don't give enough warning to do very much about the warning... Check your POH for details....

These are the observations of a PP.  Expect that some mistakes have been made in this writing.  Let me know if you find any...

Check with your suppliers of tanks, floats and displays to determine what is best for your situation.

Best regards,

-a-

Thanks!  Yes, it makes sense and much of it lines up with my experience as well.  As for #1, I will go with that assumption on my airplane.  #16 and 17 - Check.  That's about all I expect from my current gauges.  #21 - Thanks for the reminder on this one.  My annunciators light without having to press the test button.  I know this because my right fuel gauge reads low and once on a long trip - knowing I had more than 10 gallons in the right side - the annunciator illuminated some time after the gauge dropped below 48lbs.

[glenv6]

I finally got my plane back from the shop this weekend.  I had the annual done at the same time as the EDM900 installation so they had the airplane for quite a while.  I also moved from Dallas to NY in that time, so some of that wait was due to my schedule and the weather as I had to go back to Dallas to retrieve the airplane.

The shop did a very nice job on the installation.  JPI calibrated it for 64 and 93 gallons, settings which I can choose before startup.  The fuel indicators on the JPI read full until the the point where the analog wing gauges read about 28-30 gallons.  Then the indicators on the JPI drop to indicate more or less the same, as verified by the fuel used calibration on the fuel flow meter.  My original analog gauges were disconnected and covered because they were skewing the resistance in the circuit between the liquidometers and the EDM900.  Fine with me, one less distraction.

I got close to 10 hrs of flight time getting the Mooney home from Dallas on Sunday, and half of that was in fairly hard IFR.  Having all of the engine indicators within close scan of the six pack was really nice.  I am very happy with the EDM900 so far.

My FlightAware Tracks

http://flightaware.com/live/flight/N1157Z/history/20160522/1145Z/T31/KDVK

http://flightaware.com/live/flight/N1157Z/history/20160522/1750Z/KDVK/KHPN

 

[carusoam]

Glen,

What did you use to dodge the storm cells?

Thanks for posting the FA tracks.

Best regards,

-a-

[bradp]

IIRC flight aware pulls the radar from about the half way point in the track log.  It does look like there are some definitive dodges in there.  

[glenv6]

I used three things to pick my way through the worst weather.  1 - I have ForeFlight and a Stratus for ADS-B weather.  2 - The controllers were especially helpful in suggesting a waypoint north of the line of heavy crap (technical meteorological terminology) forming in front of me.  3 - I used my own eyes to steer around rain shafts when able.

I had been watching this weather for days before the trip.  By the time the day arrived I pretty much knew I would be facing IMC with scattered showers and the chance of convective weather popping up.  I was prepared to deviate or land and delay as necessary.  

This weather was fun to fly through.  The air was relatively stable, and the best thing was that the airports below were reporting VFR.  I could not have made the trip VFR even at lower altitudes, but on a hard IMC day like that it was comforting to know I could get low and pop out if I wanted or needed to.

More pictures from that trip....

 

Edited May 25, 2016 by glenv6

[TWinter]

This has been pretty well covered, but here is my .02.

I have an appointment to have the long range tanks installed in October. I told Paul at Weep No More that I had a JPI and was there any issues regarding the increased fuel capacity? He said not a problem. They just reset the unit to accommodate for the updated fuel capacity..Not a big deal. It was not a concern and done on a regular basis when they install long range tanks.

 

-Tom

[bradp]

Are there additional senders in the Monroy tanks or do they drain to and are measured by the main senders?  I'm just curious as to the design.  Especially in the later Model J's that have the GW increase STC seems like a lot of performance enhancing capabilities. 

[TWinter]

36 minutes ago, bradp said:

Are there additional senders in the Monroy tanks or do they drain to and are measured by the main senders?  I'm just curious as to the design.  Especially in the later Model J's that have the GW increase STC seems like a lot of performance enhancing capabilities. 

My understanding is that they flow into the main tank..no additional senders. My plane is a 74E, but I think the process is the same. When I made the appointment he made no mention of additional senders, just reprogramming of the JPI to show a higher capacity/quanity.

 

-Tom

[glenv6]

No additional senders.

[kortopates]

The downside to the Monroy tanks is that it becomes much more challenging to know how much fuel you have in your tanks. You only really know with certainty when you fill either the inboard original tanks only or both inboard and outboard - and then you'll know with the most certainty. With partially full tank it becomes an exercise in estimating the remaining fuel you have in the two tanks separately and going by the JPI remaining fuel once you have it calibrated. But your fuel level sensors will only tell you how much you have in your original tanks. After the inboard drain to about half, only then will the outboard tanks be empty. In fact after filling the inboards only in a few minutes the full inboards will drain into the outboard tanks perhaps making you wonder if you really filled the inboards. So I am always present at the time my plane is fueled. Also the vast majority of times I need to be there just to make sure they also don't fill the outboards so I can still take off if I am not alone! A couple of times when I wasn't there I had to have them offload fuel. Nobody wants to do that!

Sent from my iPhone using Tapatalk

[carusoam]

The upside of the Monroy tanks is, the Monroy guy will answer any questions you come up with....

the two float system handles Mooney wing tanks pretty well.  The far end empties completely before the near end can.

To improve on the system is possible.  

- There are some digital floats that supply really good data to digital indicators that display with detail.  The digital floats can be calibrated at several points in the event your tanks have unique things that make them non-linear volumetrically speaking.

- There are some really good displays for fuel level.  JPI etal....(like your JPI 900.)

- A well calibrated FF with a totalizer is simply my favorite method.  Then JPI + CIES

Best regards,

-a-

[Piloto]

The Monroy tanks are outboard of the main tanks. This causes the mains outboard float sender to fully peg up even when the Monroy tanks are not fully fueled. If you rely on the main tank panel gauges there will be a quantity uncertainty between 100gals to 85 gallons because the gauges will be peg to FULL. Best accurate way to determine fuel onboard is by using a fuel flow totalizer like the Shadin. However on occasions the fuel flow sensor may get stuck for a short time resulting on a indicated higher amount of fuel onboard. When this is observed have the flow sensor flushed with carburetor cleaner. 

José

Edited May 26, 2016 by Piloto

[FloridaMan]

The EDM-900 still uses the factory sending units, which suck. I have the gauges in my wings as well, which are spot-on accurate, as is the fuel totalizer in the EDM-900. On long trips where I take on extra fuel and add incrementally without a fill-up and then filled my tanks, the consumed fuel seems to have less than a gallon of error over 100+ gallons consumed, and that could easily be attributed to venting and marking the "fill up" 64-gallon with the tanks not filled to quite the same level under the cap between fillups. 

In short, don't expect the EDM-900 to be any better than your factory gauges as it is only a change in indication, but the totalizer kicks ass. If you don't have wing gauges, get a set.