Pierburg elect fuel boost pump.

[Guest Maj Millard]

Thought I'd get fancy recently, and fitted a new Pierburg fuel-boost pump to the Lightwing, to back up the mechanical engine pump, (912uls). The Pierburg is a nice small german rotary pump ,and comes in different max pressure ratings. I chose the low pressure one, which goes to 4.9 psi max or so, so as not to overpressurize the floats in the carbs.

 

Ran it in-line for about 5 hours, before removing it due to a few funny little occurences in flight, and it actually stopped on me a couple of times taxying out to take off, which gets your undivided attention !. Didn't seem to matter if you had the boost on or not, it would stop, especially if hot.

 

Anyway, the old Lightwing runs just fine gravity feed, as it always had. Since I've had this $140.00 pump sitting around, I decided to solicit Wals opinion at BFs, with the following questions :

 

(editored for simplicity) Wal, The Lightwing factory 912uls has no elect fuel pump fitted, (it's optional). I wish to fit a Pierburg elect fuel-boost pump into the system (low pressure pump) for back-up to the engine pump.

 

Do I need to also fit the fuel distribution block with the jetted bled-off banjo, back to the fuel tank, to eliminate over pressureizing the carbs ???.

 

Currently only have a simple 'T' fitting between the engine pump and carbs.

 

The Slepcev Storch 912uls set up has the block with bleed-off, and a 'Facet' type ticker pump as back up, what's your view on pumps ?.....

 

Wals' reply : (Love Wal, and I listen to his every word !) In regards to fitting an elect fuel pump, yes I do recommend one, however it should be the correct one for the application. The Pierburg pump is OK, IF you fit a check valve, as when the pierburg pump is switched off, normally the vanes stop in a position that restricts the fuel flow. The Facet type pumps normally do not need check valves. We normally make up a four-way barb, which replaces your existing 'T' piece so as to have a return line back to the tank fitted with a restrictor, this is not there to eliminate over pressurizing of the carbs, but to bleed off any air bubbles caused by fuel vaporization............end.

 

Please note: I have posted this for information sharing, and in the interest of SAFETY, without Wals permission....THANKS WAL.....please don't bother Wal on my behalf for more info. Thanks...........................................................................................

 

 

[Seal]

So why choose that type of fuel pump in the first place? Did it just happen to be the one lying around gathering dust on the shelf?

 

 

[Guest Maj Millard]

There are a lot of trikes where I fly with 912s, and they all use them. Plus one of the latest Gyros has two fitted, one for each tank. The mechanical fuel pump on 912s is a Peirburg also. The elect Peirburg is listed as a part in the 912 parts catolog from Rotax. A real Facet will cost you now $110.00, a friend bought one today. The new Peirburg cost $140.00 plus extra for an inline check valve, cost unknown. I saw the pierburg as possibly being a step up in fuel pump tecnology, being a rotary pump, so I thought I would investigate. It's nice that they come with different max pressure ratings. Nothing ventured, nothing gained. The Peirburg website is worth a look, those pumps are standard equipment on Mercedes, BMWs, Porches etc etc. I'm not done with it yet........................................................