Bing carb and aux fuel pump/carb heat

[Sonex1517]

I was hoping someone with a Jabiru 3300 using the Bing carb could shoot photos of their fuel setup and aux pump installation. I am also looking for photos of the carb heat install.

If you cannot post them, drop me a PM.

Thanks

[peter anson]

Hi Robbie, I have some of the information you are looking for. My fuel system is:

Fuel tap >> Auxiliary pump >> Through firewall >> Gascolator >> Fuel flow sensor >> Jabiru mechanical pump >> Bing carb

The auxiliary pump is a low pressure electric diaphragm type made by SU. It is a fairly heavy ancient design of a type that was used in many British cars in the 1950s but has been modernized slightly by incorporating some electronics instead of the original set of points. It makes a very satisfying tick, tick, tick sound as it builds up pressure when first turned on but I can't think of any other advantage to it. It is mounted on the cabin side of the firewall but could just as easily be mounted on the engine side. I sometimes turn it off after takeoff but mostly forget.

The above photo shows the air filter box with two inlets and the hot air/cold air valve. The glass fiber filter box is a Jabiru part but the original lid was too bulky to fit in the available space so I made a more compact aluminium lid. It's still a VERY tight squeeze removing the air filter element which is a flat car -type paper element.

Here's another view looking up at the filter box.
Note that these views will disappear on 31st July when Wikispaces shuts down.

Peter

[sonex892.]

Hi Robbie
Here is something very similar to Peters. The airbox is a homemade version of the Jabiru airbox. Its built to jabiru dimensions with the exception of the lid which is custom made to fit . The bit of fibreglass lower left in the shot is a socket for the cowling Naca duct air inlet to engage. This type of airbox it is a very tight fit on the firewall but not impossible.

My aux pump is a Facet located under the airbox. Fuel system. Tank > 3 way valve on fire wall > Aux pump > Gascolator > Mechanical pump > Bing

The Jabiru installation manual has some good info I'm sure will help. https://jabiru.net.au/wp-content/upload ... 7_Inst.pdf

This image will also vanish in a couple of weeks

Steve
Sonex 892

[Sonex1517]

Thanks Peter and Steve!

[racaldwell]

Hi Steve,

Nice picture of the cooling plenum. Is the inside smooth or do you have wedges of something to direct flow to any particular hotter cylinders?

I also have a filter/alt air box that came with a firewall forward kit from Jab USA. Guess I will find out what you did to modify it to make it fit.

I was planning to use the Facet aux pump from Van's.

Rick Caldwell
Xenos 0057 underway

[sonex892.]

Hi Steve,

Nice picture of the cooling plenum. Is the inside smooth or do you have wedges of something to direct flow to any particular hotter cylinders?

I also have a filter/alt air box that came with a firewall forward kit from Jab USA. Guess I will find out what you did to modify it to make it fit.

I was planning to use the Facet aux pump from Van's.

Rick Caldwell
Xenos 0057 underway

Hi Rick
That Plenum is modified from the plenum that came with the motor. It was originally the smaller plenum the type that had the plug wires run externally. I made it the same volume as the aluminium plenum I got tired of repairing. And yes it does have a deflector baffle.

You wont have any trouble fitting the base of the airbox to the firewall the difficult part is making a lid that incorporates the inlet to the carby. Resist the temptation to use scat tube here. I made the lid a 2 piece part. I'll find a photo and add it here later.

For the facet pump just make sure it is a low pressure version. From memory I think the bing requires less than 3psi?
Steve
Sonex 892

[racaldwell]

Hi Steve,

I can somewhat see the fiberglass piece connected to the carb. A picture would be nice. I don't have a clear understanding just yet of why the interferences and mods needed but one of these days I'll get there. I'm just now assembling the forward fuselage so it will be a while before I fit things to the firewall.

Guess I am one of the few people who likes to make parts out of composites. It's just the sanding and finishing of it that I don't like. But the parts under the hood don't need that level of perfection. I made a duct for my oil cooler that is mounted on the firewall of my RV-6. It is now 19 yrs old and looks just like when I made it. A final brush down of neat epoxy to seal any pinholes made the outside slick looking and never touched a piece of sandpaper to it afterwards.

Rick
Xenos 0057

[sonex892.]

Hi Rick.
The mods to the lid are to reduce the turbulence entering the throat of the carb. For the bing to work correctly it needs a nice smooth airflow. I discovered / learnt about this the hard way on my previous aircraft a Jabiru powered Sonerai.

On tight installations Jabiru use what they call a cobra head. It's basically an expansion chamber before the carb throat. The goal was to make the lid into a cobra head. I made the lid in one piece then realised I couldnt remove it to get to the filter. So the easy way out was to make it a 2 piece lid. It isn't that pretty, being a prototype I made it out of polyester. After my previous experience I wasn't expecting it to work straight away, but fortunately it did. I always intended to make a nicer one with epoxy. But 8 years later it works, so I cant be bothered.

[racaldwell]

Thanks, Steve, for clarifying this for me. So you had a large spread of EGT readings before and afterwards all were about even? I am just wondering if I do not get it right, what will be my indications.

Rick
Xenos 0057

[sonex892.]

Thanks, Steve, for clarifying this for me. So you had a large spread of EGT readings before and afterwards all were about even? I am just wondering if I do not get it right, what will be my indications.

Rick
Xenos 0057

Hi Rick
No not the EGT spread. it is the mixture adjustment itself that will be affected by the inlet air. Indications I had with the Sonerai were, it was unable to make much power and black smoke.
Steve
Sonex 892