Fuel tank capacity VS display level

[astaib]

Hi all,

What are the capacity of each of the tanks in our planes?

My version isn't the long range version so I have 20 gallons in each wing, but as there are 2 interconnected tanks in each wing I'm asking what are the capacity of each of the of the 2 interconnected tanks.

My display on the VM1000 system is only showing the fuel level from 0 to 15 gallons:
-is it because the sender is only measuring the fuel level in the biggest tank of each wing?
-is it because the sender is too short?

My question behind is: Will I be able to display the fuel level from 0 to 20 gallons with a new engine data manager (i.e: the EI CGR-30 that I'm about to buy)?
In this case, do I have to buy the IE senders at the same lengh as today (66'') or longer ones?

Thank you for your knowledges.

Arnaud.

[danno2000]

Hi all,

My display on the VM1000 system is only showing the fuel level from 0 to 15 gallons:
-is it because the sender is only measuring the fuel level in the biggest tank of each wing?
-is it because the sender is too short?

My understanding based on the fuel system diagram in section 7.10 of the AFM is that because the sensor only extends outboard to the top of the interconnection point, the wing geometry is such that the outboard sub-tank is slightly higher and will empty partially before the inboard sub-tank level that the sensor is reading begins to drop.

So if your new sensors use the same configuration, I'd expect them to have the same limitation. And based solely on the diagram, I'm not sure how you'd get a sender out to the far edge of the outboard sub-tank.

The diagram I'm talking about is page 7-31 of this file (it's a different page in my AFM but the information is substantially identical): https://ramaviation.com/wp-content/uplo ... ressed.pdf

Hope this helps and highly invite others to tell me I'm wrong if I am.

cheers,
dan

[DBMX]

Hi all,

What are the capacity of each of the tanks in our planes?

My version isn't the long range version so I have 20 gallons in each wing, but as there are 2 interconnected tanks in each wing I'm asking what are the capacity of each of the of the 2 interconnected tanks.

My display on the VM1000 system is only showing the fuel level from 0 to 15 gallons:
-is it because the sender is only measuring the fuel level in the biggest tank of each wing?
-is it because the sender is too short?

My question behind is: Will I be able to display the fuel level from 0 to 20 gallons with a new engine data manager (i.e: the EI CGR-30 that I'm about to buy)?
In this case, do I have to buy the IE senders at the same lengh as today (66'') or longer ones?

Thank you for your knowledges.

Arnaud.

Capture d’écran 2024-09-30 083707.jpg

Hello, the capacity for the DA40-180 is 40 Usable gallons (20 usable per wing as you know). Im not sure how much fuel the Inboard chamber holds individually compared to the outboard fuel chamber. The 66" probe is standard and does show up to the 20 gallons the tanks hold. My only guess would be the VM1000 has some weird limitation, I have never personally worked on that type of gauge. The DA40's I work on have G1000 systems in them and the 66" fuel probe reads 20 Gallons correctly. Basically, I don't think the sender is too short and 66" should work. Im curious, when you fill up your tanks do you pay for 40 gallons or 30 gallons? Or do they not "top it off" and only put into the tank what you ask them to? Its very bizarre to me your gauge reads 15 gallons max when the tanks can hold 20.

I hope I was some help to you, attached is a picture of what the G1000 displays on RH and LH tanks with the 66" fuel probe.

Best, Drew

[astaib]

Hi all,

What are the capacity of each of the tanks in our planes?

My version isn't the long range version so I have 20 gallons in each wing, but as there are 2 interconnected tanks in each wing I'm asking what are the capacity of each of the of the 2 interconnected tanks.

My display on the VM1000 system is only showing the fuel level from 0 to 15 gallons:
-is it because the sender is only measuring the fuel level in the biggest tank of each wing?
-is it because the sender is too short?

My question behind is: Will I be able to display the fuel level from 0 to 20 gallons with a new engine data manager (i.e: the EI CGR-30 that I'm about to buy)?
In this case, do I have to buy the IE senders at the same lengh as today (66'') or longer ones?

Thank you for your knowledges.

Arnaud.
IMG_5138.jpg
Capture d’écran 2024-09-30 083707.jpg

Hello, the capacity for the DA40-180 is 40 Usable gallons (20 usable per wing as you know). Im not sure how much fuel the Inboard chamber holds individually compared to the outboard fuel chamber. The 66" probe is standard and does show up to the 20 gallons the tanks hold. My only guess would be the VM1000 has some weird limitation, I have never personally worked on that type of gauge. The DA40's I work on have G1000 systems in them and the 66" fuel probe reads 20 Gallons correctly. Basically, I don't think the sender is too short and 66" should work. Im curious, when you fill up your tanks do you pay for 40 gallons or 30 gallons? Or do they not "top it off" and only put into the tank what you ask them to? Its very bizarre to me your gauge reads 15 gallons max when the tanks can hold 20.

I hope I was some help to you, attached is a picture of what the G1000 displays on RH and LH tanks with the 66" fuel probe.

Best, Drew

Hi Drew,

Thank you very much for your feedback.
On your picture of the G1000, why is the green arc stopping at approx 17GAL and not to 20? Is it a DA40 whith longe range tanks installed?

I have read some times ago that the display of the VM1000 can be calibrated to show MAX at 15 gal and some other to show MAX at 17 gal (maybe because of long vs normal range tank installation? Or maybe to an evolution that has occured during the DA40 production? I don't know. => Maybe some of you can help ).

I has always seem strange to me not to be able to read the fuel level between 15 and 20 gal, but now I'm used too!
As I will shortly upgrade my VM1000 to a CGR-30P, I was asking myself if the CGR30P will measure from 0 to 15 gal or from 0 to 20 gal.

I don't know what you exactly means by " Im curious, when you fill up your tanks do you pay for 40 gallons or 30 gallons?", but I can confirm that I have 20 gallons in each wing. When I land with low fuel, I'm definitely adding more than 30 gal total.

Enclosed picture of my very nice VM1000 fuel level display showing maxi at 15 gal

Arnaud.

[Rich]

The fuel probes can only measure the level of fuel in the inner chamber, which is partially affected by the fuel level in the outer chamber. Due to the wing dihedral the upper level of the outer chamber is higher than the fuel probe can possibly reach, as the upper corner of the inner chamber limits it. At a point where the fuel level is higher than the highest point of the fuel probe, this additional fuel can not be measured. This happens above 17 gallons.

[Rich]

It's the airplane wing/tank geometry, The G1000 has the same limitation. From the POH 4A.3.1:

Standard Tank (G1000 instrument panel):

When the fuel indicator reads 17 US gal, the correct fuel quantity must be determined with the fuel quantity measuring device. If this measurement is not carried out, the fuel quantity available for flight planning is 17 US gal.

This limitation will exist for any EIS unless one modifies the outer chambers to accommodate additional sensors with special capabilities to measure that additional 3 gallons.

NOTE: The pre-2002 DA40s' limit is 15 gallons, not 17. It's unclear if use of a different probe would change this. There might be a limitation inside the tank that would preclude the installation of a probe that would change this.

[Rich]

BTW, examination of the DA40NG manual leads one to conclude that the inner chamber volume is 14 gallons and the outer is 6. This does not mean that the first 6 gallons draws down the fuel only in the outer tank. It's probably something between 2-3 gallons. Then it draws down from both. At some hard-to-predict level the outer chamber will be fully empty. This is way below 14 gallons and might be somewhere around 7 gallons.

[astaib]

It's the airplane wing/tank geometry, The G1000 has the same limitation. From the POH 4A.3.1:

Standard Tank (G1000 instrument panel):

When the fuel indicator reads 17 US gal, the correct fuel quantity must be determined with the fuel quantity measuring device. If this measurement is not carried out, the fuel quantity available for flight planning is 17 US gal.

This limitation will exist for any EIS unless one modifies the outer chambers to accommodate additional sensors with special capabilities to measure that additional 3 gallons.

NOTE: The pre-2002 DA40s' limit is 15 gallons, not 17. It's unclear if use of a different probe would change this. There might be a limitation inside the tank that would preclude the installation of a probe that would change this.

Thank you very much for this, it is very clear to me now.

I'm only wondering if my pre-2002 DA40 has a tank with a different geometry...
Did you already asked this to Diamond?

As EI have to parameter the CGR 30P before shipping it to my IA, I'm wondering if this can affect the setup...

Arnaud.

[Rich]

Thank you very much for this, it is very clear to me now.

I'm only wondering if my pre-2002 DA40 has a tank with a different geometry...
Did you already asked this to Diamond?

As EI have to parameter the CGR 30P before shipping it to my IA, I'm wondering if this can affect the setup...

Arnaud.

When you say parameter, what exactly is needed? I hadn't thought about the 15 gal vs 17 gal difference but there are several possibilities, including a difference in chamber lengths pre-2002 vs. later. The 15 vs 17 gal might be a factor of overall length or a difference in internal effective measurement area. At the very least (hate to say it) you should probably pull a probe and get its physical dimensions.

Depending on what causes the 15 gal limitations you might wind up with a ~17 gal limit. I haven't looked at EI's installation in detail. Are the probes calibrated after installation as are the VM1000 and the JPI setups or done by EI ahead of time? That would be a considerable complication.

[DBMX]

The long-range tanks were not installed on the aircraft in the picture of the g1000 unit. Extended tanks also add 5 gallons per side (so it would be 50 usable gallons) we have a few DA40s with the long-range tanks installed. How long have you had the VM1000 installed? It seems very unlikely (and I've never seen a fuel tank part number superseded for any DA40-180 of any serial number) that the fuel tank would hold less fuel than other DA40's. It could have been a change of regulations since you've had the VM1000 installed allowing a 17 gal limit with other indicating systems. I would check still if you have the same fuel probe that the IPC says "should" be installed by getting the dimensions of it like Rich previously mentioned. You may be able it get a part number off of it without removing the wing if you're lucky! or at the very least you may not have to pull the probe out.