Keep everyone up to date with how your project is coming along.
I'm about 70% of the way through building my aircraft. It is time to turn my attention to the fun stuff.
I know I could just slap the mechanical fuel system on and go fly, but experimenting is why I'm building this thing.
For the next 3 months, I'll be working on all the firewall forward stuff for the project, with hopes of hanging the engine before the end of the year.
A little about the engine: It's an air cooled horizontally opposed 360 cu in 4 cylinder, producing 200 hp at about 2700 RPM. Each cylinder has 2 spark plugs. The engine itself is professionally built - all parts are standard Lycoming parts, "zero time" - per standard Lycoming procedures.
A little about my approach:
I plan to run dual management systems. This consists of dual ECUs (microsquirt), 8 coils (4 controlled by each ECU during normal operation), 4 injectors (2 controlled by each ECU during normal operation), dual fuel pumps (either pump can run both systems, both pumps on at takeoff), dual battery / alternator power system, dual crank sensors, etc...
In event of ECU failure, the other ECU will take over the other 2 fuel injectors, and continue to operate on 4 coils.
My overarching design goals are:
1. any single failure cannot stop engine from running. There will be exceptions to that, which I will note as I go along.
2. system operation should be fairly straight forward and conventional for general aviation aircraft.
3. if possible, I'd like to build a setup where a single failure will be self recoverable (ie. engine will run with near full power, and a fault light indicates failure - as opposed to requiring pilot to take action)
I welcome your feedback as I share the design - hopefully you will catch things I had not thought of. Some aspects of the wiring will be different than traditional EFI circuits - for example, injector power can't just go to a single fuse (fuse blows, engine out).
What I'm doing has been done before - in fact i can buy a turnkey system for about $6k (one ECU). I'm doing this because... I want to.
Starting off, mounting injectors. Lycoming has an intake port for mechanical injectors, which are basically a feed tube with a nozzle and a pipe fitting.
I fabricated this injector housing. Have not test fired it yet. Fuel will get here from a central block with a dead run at the end. This approach has been tried without any ill effects with hot start after heat soak, so I'll go with. Bolts in this pic are 0.2" too long as I was playing with housing clearances.
Eventually all the parts will be anodized or plated before putting in use (need to research what works with 10% ethanol)
This shot shows where injector will be injecting (background, behind the valve)
Interesting proyect, what type of induction system ? its a plenum and throttle bodie or individual throttles bodies ?
Can you share a picture of the complete engine.