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-   -   Fuel pump head pressure? (https://www.rcuniverse.com/forum/rc-jets-120/11683702-fuel-pump-head-pressure.html)

900LX_driver 10-15-2020 10:00 AM

Fuel pump head pressure?
 
Hey everyone,

Sorry if this is the wrong forum for this question, mods feel free to move it if it is. I am new to turbine aircraft, so I’m just now getting everything together for the fueling, etc. I have the HSD steel fuel can, which runs either a 2S or 3S lipo; I was advised to stick with the 2S to avoid generating static from too much pressure going into the (model’s) tank.

My question is: Is there a rule of thumb you guys use to determine adequate fuel pressure coming from the fuel can? I know the HSD has a variable speed pump, I just haven’t had a chance to use it yet and I think the electric gauge it has only measures battery voltage.

Anyways, if you guys have any recommendations for this, I would surely appreciate it.

- Steven

Dansy 10-15-2020 10:35 AM


Originally Posted by 900LX_driver (Post 12638471)
Hey everyone,

Sorry if this is the wrong forum for this question, mods feel free to move it if it is. I am new to turbine aircraft, so Iím just now getting everything together for the fueling, etc. I have the HSD steel fuel can, which runs either a 2S or 3S lipo; I was advised to stick with the 2S to avoid generating static from too much pressure going into the (modelís) tank.

My question is: Is there a rule of thumb you guys use to determine adequate fuel pressure coming from the fuel can? I know the HSD has a variable speed pump, I just havenít had a chance to use it yet and I think the electric gauge it has only measures battery voltage.

Anyways, if you guys have any recommendations for this, I would surely appreciate it.

- Steven

Personally I donít fuel my jets very fast, I always install a 4mm on the refueling side....and slow the pump down on a 2s (jersey system), I also used only high flow vents....the only concern is to not crack or burst your fuel tank with too much pressure....even fueling slow with 4mm, once full with the Taxi tank installed it always that a couple minutes before the pressure stabilize....

If itís a plastic fuel tank be twice more careful....

ww2birds 10-15-2020 12:30 PM

Good advice from Dansy. Be careful with fast fueling rates. 5psi is a lot .. it is easy to fracture hard-walled tanks (e.g. fiberglass, or especialyl kevlar).

The thing to remember is that the problem typically comes from the vent lines .. when they have air in them, they can support a high filling rate. Once the tank fills (or the first tank fills and it starts on the second "in-series" tanks) there is liquid in the vent lines and the pressure can build VERY fast. This can occur with series-connected tanks in the jet, or with the overflow tank. A variable speed pump is great and if you can baby sit it, you can go fast when the vents have air in them, and then slow down.

I've done a lot of work building fueling stations so have instrumented all this on the bench...

Dave

patf 10-16-2020 04:26 AM

I added one of these to my old jersey modeler to provide the control we need. You can fine ones with digital displays if you want more info.

https://smile.amazon.com/Controller-...d-0c3639671b2d



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