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fuel pump


sandman

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The black plastic one that was on my mates factory built (Austflight Boonah) drifter years ago was a Ecco brand, I remember because a bought one to put in my aircraft.

 

Similar if not the same as this one http://www.ebay.com.au/itm/12-volt-SU-Type-Diaphram-Electric-Fuel-Pump-1-LPM-3-psi-Ecco-Universal-NZ-Made-/131408801642?hash=item1e98932f6a:g:E08AAOSwLVZV2WxF

 

 

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  • 2 weeks later...

Ayecapt

 

I have only used a camera: but I suppose has the same results.

 

If any one requires a quick reference for the "Repco" there are two valves, the outlet I didn't remove.

 

spacesailor

 

RepcoPump.jpg.cd0300ef321b2e80a9c6d24c15ffcf7f.jpg

 

 

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Hi guys, do you anticipate any problems with flying a Jabiru LSA with fuel pump on all the time? I sometimes leave it on lest I forget to put it on during a steep climb or during a touch and go or if I need to go around. If this a bad habit, then why and what problems am I likely to encounter?

 

 

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I never turn the fuel pump off on my Jabiru which has about 130 hours on the clock. In fact, the manual says it does no harm. (Might wear out prematurely).

 

 

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No, try to get into the habit of turning it off and on as required because you'll possibly start flying other aircraft other than Jabirus. Should be part of the downwind checks. Remember, it's a backup pump in case the engine fuel pump dies.

 

 

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Remember, it's a backup pump in case the engine fuel pump dies.

Exactly. If you don't turn the back up pump off in cruise you will not know if you have had an engine pump failure which could leave you relying on the electric pump only.

 

Note that taxi and up to about 2300rpm (or more) can be achieved with gravity only, so a check at cruise is necessary to know that you actually have a backup pump in working order.

 

A pilot check of the electric pump is achieved in priming but there is no pilot check of the mechanical pump other then at high power settings - the 2000rpm mag check can be achieved with gravity alone.

 

(I am referring to the Jabiru set up ONLY in this case i.e. With high wing tanks & not the J120 set up)

 

 

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In a Jab LSA the fuel tank is at the same level as the engine, behind the seats. If the main engine pump fails during a critical phase and if you do not have your back up pump turned on, will you not lose engine power due to the fuel supply being cut off? Is it not best to leave it on rather than take a risk if the tank is at same level as the engine?

 

 

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Anjum - the electric fuel pump is also there to overcome problems of vapour lock in a system which is not full gravity feed - as in the LSA55.

 

The check sequence recommended to me by a CASA-approved Test pilot is: prior to starting the engine, turn on the electric fuel pump and check the fuel pressure reading ( it should be around 4 psi.) Then, turn OFF the electric pump and start the engine and check the fuel pressure reading for the mechanical pump alone (should be about the same). Then, when you do your run-up and mag. drop check, turn on the electric pump again prior to the run-up as part of your standard procedure, so you don't forget it.

 

 

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LSA? Many LSAs including my J230 ? (I see now LSA55 - I don't know them, I presume the forerunner to the J120?)

 

If you have 2 pumps running all the time how do you know when one fails - except when both fail.

 

Close to the ground (TO & L) is good, but otherwise ................ Anyway up to you just a couple of points you might like to consider.

 

 

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Frank - the LSA55 was the first 'production' model of Jabirus (with variants including the St1 and St3, the SK and SP) , and all with the solid foam wings and fuselage tank arrangement - yes, the forerunners of the J120. I believe the LSA55 model number came from a combination of Light Sport Aircraft and the 95.55 rego. status, though I have to admit that is an assumption on my part.

 

 

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Yes, I always put it back on during the run-up / pre take off check. My concern is that do I need to put it back off once I am at cruising altitude and on leaving the circuit pattern? I am worried that in case I need to do a cruise climb and climb up further due to terrain, while I am cruising, then the engine position being higher than the fuel tank behind the seats during the climb, may lead to fuel starvation to the engine, lest I forget to put the fuel pump on in a Jab LSA-55. Hence I find it safer to leave it on during my entire flight.

 

Also would my battery go flat if I leave it on too long, or is this not a problem as long as the engine is running continuously and probably charging the battery?

 

I always check the fuel pump during the pre-start check to make sure that both pumps are working and taxi witht the electric fuel pump off. I put it on during the pre-take off check.

 

 

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Frank - What you are saying makes a lot of sense. I am getting your point. The electric pump we have is just a back up and the reason we put it on during the take off is to ensure that we have enough back up available should the mechanical pump fail during the initial climb (the most critical phase of any flight). Once we are at cruising altitude, then we just use the in built mechanical pump by putting the electric pump off. And if by one's bad luck the in built mechanical pump fails, then use the electric pump as a back up!

 

And during the normal cruise climb, the in built mechanical pump would deliver enough power for the fuel to be pumped normally to the engine, even if the tank is at a lower level than the engine during the climb. Am I correct in my understanding, and does this set up work even with a Jab LSA-55 which has the fuel tank behind the seats (at the same or lower level than the engine) and no wing tanks?

 

 

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