D-180: calculation of fuel left in both tanks using one FF transducer
- Thread starter kerstens
- Start date
jakej
Well-Known Member
Fuel level gauges are used normally to determine quantity in tank/s, Fuel Flow is computing fuel used (plus other calculations) in total.
Any particular reason to do it differently to what is universally done ?
Any particular reason to do it differently to what is universally done ?
jakej
Well-Known Member
There may be a solution,
What aircraft type is it ?
Pm me if you wish.
What aircraft type is it ?
Pm me if you wish.
FWIW: I have one FF transducer on a low wing airplane and have set the DYNON fuel flow to tell me to change tanks after every 5 gallons. During the pre-flight I measure and write down on my kneeboard how much fuel I have in each tank. Then when the DYNON alarms goes off in flight I switch tanks and subtract 5 gallons from that tank's amount on my kneeboard. When I fuel up, it is amazing how accurate the remaining amount is in each tank compared to my kneeboard. After 6 yrs and over 700hrs of flying using this procedure I am confident the in-flight amount I have on my knee-board is very accurate.
YMMV
YMMV
It is an FK14B ultralight.
jakej
Well-Known Member
As Galin says, YMMV. Your situation may be different.
As you most likely have a Rotax fitted does your FK have a fuel return line ? To where, both tanks or just one ?
What make/type of fuel level sensor is currently used ?
Where is it installed ? Easily accessible or would you need to remove the wings ?
IMO a fuel level system, doesn’t matter if it’s a sight gauge or float or capacitance system, is a bit of insurance regardless of whether regulations require it or not or high wing or low wing.
If the fuel cap comes off a high or low wing aircraft you’ll never know how much fuel you lost with just a FF sensor, when you do notice it happening. I’ve seen fuel streaming overboard in a couple of aircraft, one guy lost approx 20 litres in only a few minutes by the time he got on the ground again.
HTH.
Yep it is a ROTAX912S. No fuel return line. Both fuel level sensors are dead. Need to cut open the carbon fibre wing near the root to replace them. A very costly affair. So to replace the fuel level senders is not an option for me. Therefore the question whether with the aid of one FF sender I could have the same readings as offered by the fuel level senders.
jakej
Well-Known Member
I understand your pain however if you are not impacting on the top or bottom surfaces of the wings then I don't see a huge cost, its just a pita 
I have done this type of work before on my own composite aircraft & others.
I'd still be interested to know -
What make/type of fuel level sensor is currently used ?
Where is it installed ? Easily accessible or would you need to remove the wings ?
I have done this type of work before on my own composite aircraft & others.I'd still be interested to know -
What make/type of fuel level sensor is currently used ?
Where is it installed ? Easily accessible or would you need to remove the wings ?
Hi jakej,
The wings can be easily removed. However in the root of the wings the de-rigging system is placed. Therefore difficult acces to the tanks. Result is that only acces from the top or bottom of the wing is feasible.
The fuel level senders are installed near the root of the wings. I do not know their type.
The wings can be easily removed. However in the root of the wings the de-rigging system is placed. Therefore difficult acces to the tanks. Result is that only acces from the top or bottom of the wing is feasible.
The fuel level senders are installed near the root of the wings. I do not know their type.
jakej
Well-Known Member
I've been trying to reach out to the FK dealer here but no luck so far, is it possible to get a picture of the wing root area ? I'm guessing the fuel level sensor is in that area.
"The fuel level gauges in my tanks are dead! Prone to failure!" Is this a known problem ? Did yours ever work ?
"The fuel level gauges in my tanks are dead! Prone to failure!" Is this a known problem ? Did yours ever work ?
Affirm, they were working. The fuel level sender are of a resistive type. They are prone to failure like de VDO restive senders. Peter Funk has confirmed that the fuel level senders are near the root of the wings. They are protected by sloshing walls.
jakej
Well-Known Member
Please pm me his contact details- I have an idea I want to discuss with him using capacitance fuel level senders.
At a technical level, there isn't a way to have fuel flow measure/compute individual tank quantities. It's always total fuel on board.
jakej
Well-Known Member
Give me a few days & I’ll report back.
Hi jakej,
If a capacitive fuel level sender could be retrofitted it would be a very nice way to solve the problem of failed resistive fuel level senders. The wire problem should be solved as well as that the disk of ca 70 mm diameter 20 mm high should be covered by teardrop bubble.
If a capacitive fuel level sender could be retrofitted it would be a very nice way to solve the problem of failed resistive fuel level senders. The wire problem should be solved as well as that the disk of ca 70 mm diameter 20 mm high should be covered by teardrop bubble.
jakej
Well-Known Member
kerstens,
I have been in contact with Peter however, as this is more about your airframe, rather than Dynon 'issues', I will pm you with some information.
I have been in contact with Peter however, as this is more about your airframe, rather than Dynon 'issues', I will pm you with some information.