Fuel System

07-06-2015, 08:21 PM

tthunne | Fuel System

Has anyone installed a fuel system per the Airflow Performance schematic for the Seawind?

Tom Thunnell

07-11-2015, 10:59 AM

Larry Brunzlick | Air Flow Performance Fuel Pumps

I have the Dual Pump Package #8 Inlets. Part number 3090061 from Air Flow Performance. No problems with it and each pump delivers 40+ PSI. I have a separate switch for each pump. I only run one pump at a time. I could not find the Schematic that you refer to on their website. As I recall It came with the two pumps and pressure relief all plumbed together and wiring ready to be hooked up. The unit is fed from my fuel selector and feeds directly to my engine in series with the engine driven pump.

Larry Brunzlick

07-11-2015, 05:15 PM

tthunne | Fuel System

Larry:

I attended one of the classes AirFlow puts on and they provided us with 14 diagrams for suggested systems for various homebuilts, one of which was the Seawind. They said a number of Seawind builders had installed the system they described with no problems.

They didn't want to seem to critical but really didn't understand the complexity of the original Seawind system.

It's fuel system schematic #11 in appendix A of their manual and it is the dual pump pkg. #8.

It has fuel from the selector to the header, out from the header to their fuel filter then to the pump package and out to the engine driven fuel pump. The relief valve line plumbs back to the header which is vented. They recommend the purge valve line be run back to either the header or a fuel tank to guarantee no vapor or hot fuel is recirculated. You can run the pumps however you choose, one or both continuously, one continuously and the second at high altitude or any other combination.

Thanks for your response, TLT

07-11-2015, 09:54 PM

tthunne | Fuel System

Larry:

I neglected to mention that I have the complete Airflow Performance FI system.

Many builders use the only the Airflow pumps and may not have a purge system which allows the circulation of cool fuel through the system to eliminate the hot start problem,

TLT

07-12-2015, 06:09 AM

Mike

I agree with airflow. I replaced the original fuel system 8 years ago and haven't looked back! NO problems. I also run one pump all the time.

07-12-2015, 04:37 PM

tthunne | Fuel System

Mike:

That's good to hear, the fuel system, as you are well aware, has been a bone of contention since the advent of the Seawind. And any mention of it has been considered as opening a can of worms!

07-23-2015, 06:54 AM

Mike

Na..... same old can of worms... Some of us are getting to be pro's at this conversation...!

P.S. - I will be installing the package on the Seawind I am rebuilding now.

08-11-2015, 11:44 PM

Larry Brunzlick

I too have the complete Airflow Performance FI system. My purge line feeds back to the left main tank. It sounds like my system is the same as yours minus the header tank(s). Where the fuel line to the engine connects to the Airflow induction/throttle, there is another micro porous metal filter. Be aware that this filter will probable get clogged no mater how clean you think your wings were when you closed them. The good thing is, it is not catastrophic. You will notice a gradual decline in the peak fuel flow with mixture full rich at takeoff. An ultrasonic jewelry cleaner works great for getting the particles out.

Larry

08-12-2015, 08:47 PM

tthunne | Fuel System

Larry:

Good tip ! I was wondering how to clean that thing and never thought of that device.

08-14-2015, 07:29 AM

Mike

Quote:

Originally Posted by Larry Brunzlick View Post

Larry

Hummmmmm, there is a lot to be said here, however this is the short version.

You should have a filter before the airflow package as per recommendations via airflow. There is also a small filter in the engine itself (I think that is the one you are talking about) which should not get clogged if there is a filter before it, however I have seen debris on that engine filter. Each year at annual you should clean all filters. In a new Seawind I would check every few hours.

We could possible consider this as one of the causes of one accident.

08-14-2015, 08:38 PM

Larry Brunzlick

I do have a filter before the Airflow dual pump package and it is very fine but apparently not fine enough because the filter at the engine still got clogged. High EGT temps were the first things I noticed because I did not always look at the fuel flow rate at full power after take off. I do now. The problem should diminish over time with repeated cleanings. An A&P in Traverse City, MI clued me in to use of an ultrasonic cleaner when we aborted our trip to the 2013 ISPA flyin.

Larry

08-15-2015, 09:26 PM

tthune | Fuel System

Mike:

Even though Airflow doesn't recommend it I have a high performance 75 micron filter that can be used on the suction side of fuel pumps in line before the Airflow Pkg. According to the Mfg'r essentially no pressure drop or vaporization at our fuel use rate.

08-28-2015, 07:18 PM

tthunne | Fuel System

The certified Seawind will have no header tank nor any check valves. Does anyone know anything more regarding the certified system ?

08-30-2015, 06:25 AM

Mike

No but I would need to see the configuration of the fuel system before comment.

I don't really agree with no header tanks

08-30-2015, 08:06 PM

tthunne | Fuel System

I had a number of conversations with Paul Marshal while he was still active with Seawind before his unfortunate illness.

The discussions focused on how to improve the kit Seawind. He said if he were to build one he would first use only aircraft components, no automobile parts such as the fuel pumps, without question no slider and no header tank and check valves. This is when he indicated that the certified version would not have them and he thought this validated his opinion. He said they were investigating introducing solid baffles near the wing roots such that there would be formed essentially 3 gallon sumps at each wing root. The baffles would be equipped with a free swinging, hinged metal flap covering a substantial opening. The "flaps" would hinge on the wing root side of the baffle to prevent fuel from sloshing away from the fuel outlet. The seal would be such that it could leak slightly but still maintain plenty of fuel in the right place in an uncoordinated turn or turbulence etc. He was going to check further but then everything was interrupted because of his illness and I never did hear what other design elements went into the certified fuel system.

11-20-2016, 09:41 PM

tthunne | Airflow Performance

I had some recent discussions with AP over another issue and we did however discuss additional fuel filters.

AP's filter in their package is designed and sized for their pump protection and not for providing clean fuel to the engine. I emailed my pump and filter setup so we were sure we were on the same page regarding what we were discussing.

He noticed my inline filter before his pump and filter setup and strongly suggested that I remove it and place it between AP's package and the engine driven pump. Notwithstanding the fact that my filter was sized for a max flow of 250 gallons/hr with little pressure drop and none at 40 to 50 gpm he still strongly urged its move.

They changed the rotation of my purge valve for me at no charge and quickly.