Rotax 916IS Fuel Pump

Why would you not use the one Rotax supplies?  There are a large number running in the USA currently on 916 now with them, no problems that I have heard of.  

Cheers

When you say, "...theirs requires 20A per pump," I presume you mean that each pump is protected by a 20A fuse.  It's very unlikely that Edge's pumps draw 20A each, as that would represent more than double the available generating capacity of the "A" electrical system.

Wire should be chosen to provide the necessary current at an acceptable voltage drop and wire temperature rise, then a fuse should be chosen to protect the wire.  Fuse values don't necessarily match the maximum current demand of the device at the end of the wire.  Many aviation suppliers over-specify wire gauge and fuse ratings; Edge wouldn't be the first.

The pumps are stamped with “20 AMP Fuse Required”. They use an IT Automotive / Walbro high output pump. I’m not sure if they can draw that or not. The specs imply they can. I really like the setup since it’s simple manifold design with few fittings to leak, really nice. The Rotax pump / system design has a ton of fittings and requires replacement at 150 hours currently. It’s a Bosch pump. I’d love to see what others have. The Rotax isn’t a given since they’ve stated that it’s up to the airframe manufacturer and isn’t included with the engine like it is on the 915. 

Hi Jason

I am not sure where you found the statement that there is a 150 hour replacement, I can't find that anywhere.  In the SI pac on the pumps it shows the continued airworthiness and you check for leaks is all it says at annual and 200 hour.  

Given that the pumps are a separate part from the engine the guidance is in the SI-PAC-026 , copy attached.  This allows the OEM to place the pumps where they need to be without constraints of the stainless fire box.  These pumps are not required to be in a stainless box like the others supplied with the 912 and 915 iS engines.  (they pass the fire test without the box)  The SI shows that there are multiple solutions to configuration dependent on the needs of the builder.  The use of standard aviation fittings also solves issues of conformity for any certified users.  

Cheers

There’s a Rotax letter NTO-916 is the title that states the 150 limit. They say they may increase as they gain more data.