Aircraft Fuel Injection for Ultima
Discussion
Some viewers of my buildsite saw a photo of the aerobatic plane that I built, and have asked me via email if I thought that a similar fuel injection system would work on an auto. At first, I thought that would not work well, but, thinking about it, it might be possible and work reasonably well. Here's what it looks like
http://home.comcast.net/~rosenracing6/wsb/html/view.cgi-photo.html--SiteID-2444685.html
http://home.comcast.net/~rosenracing6/wsb/html/view.cgi-photo.html--SiteID-2444694.html
The aircraft system is a pure mechanical one, using a fuel servo that meters fuel to a fuel distributor known as a "spider". Each cylinder has it's own injector which is mounted in the cylinder head just ahead of the intake valve. As long as there is fuel pressure in the spider, fuel is being sprayed into the intake passage. Each injector is supplied by a small stainless steel piece of tubing from the spider.
The servo determines how much fuel to send to the spider by 1. measuring the amount of air entering the servo. There are 4 small tubes at the entrance of the servo that project into the airstream. If there is no air moving into the servo, it shuts off the fuel (as in the time in my Mooney when the tubes iced up due to a faulty ram air plenum that was supposed to be closed. The result was the engine shut dowm. Fortunately after I descended 10,000 feet (no choice), and got into air that was above freezing, the engine re-lit).
2.Throttle position and mixture setting also determine how much fuel is being fed to the spider.
Aircraft need a method of leaning out the mixture as the aircraft climbs since the air is less dense with altitude. This is a simple choke type of cable operated from the cockpit. Mixture is determined by either sound of the engine, or an exhaust temp. gauge.
This feature could be an advantage in a car if changing altitude, or trying to stretch out a fuel supply. Modern race cars do this to extend their range at times.
The main disadvantage I see is that since an aircraft engine is usually running at a constant rpm between 2500-2700, so there is no provision for an accelerator pump.
Fuel pressure is maintained by a mechanical pump (30-40 lbs.)and starting is accomplished with an electric prime pump. This pump will also feed the engine if the mechanical pump fails.
Shut down of the engine is by pulling out the mixture control to shut the fuel off to the engine. Turning off the engine by spark shut-off will flood the engine.
The engine in the One Design is 360 cu. in. Six cylinder engines are usually 540 cu. in., so there is no problem with the servo handling an auto engine.
Servos that are serviced and signed off for legal aircraft use are expensive, but one that is not should be well under $1000. Nozzles come in all different orfice sizes. As a matter of fact, if you look closely at the baffles on the engine, you'll see a small plaque mounted, that tells what size nozzle belongs in that cylinder, since each cylinder has been combustion measured. That's another story for another time!!
If this system would work, it might not do as well as a modern EFI, but I think it would be better than a carb.
Regards
Jack
http://home.comcast.net/~rosenracing6/wsb/html/view.cgi-photo.html--SiteID-2444685.html
http://home.comcast.net/~rosenracing6/wsb/html/view.cgi-photo.html--SiteID-2444694.html
The aircraft system is a pure mechanical one, using a fuel servo that meters fuel to a fuel distributor known as a "spider". Each cylinder has it's own injector which is mounted in the cylinder head just ahead of the intake valve. As long as there is fuel pressure in the spider, fuel is being sprayed into the intake passage. Each injector is supplied by a small stainless steel piece of tubing from the spider.
The servo determines how much fuel to send to the spider by 1. measuring the amount of air entering the servo. There are 4 small tubes at the entrance of the servo that project into the airstream. If there is no air moving into the servo, it shuts off the fuel (as in the time in my Mooney when the tubes iced up due to a faulty ram air plenum that was supposed to be closed. The result was the engine shut dowm. Fortunately after I descended 10,000 feet (no choice), and got into air that was above freezing, the engine re-lit).
2.Throttle position and mixture setting also determine how much fuel is being fed to the spider.
Aircraft need a method of leaning out the mixture as the aircraft climbs since the air is less dense with altitude. This is a simple choke type of cable operated from the cockpit. Mixture is determined by either sound of the engine, or an exhaust temp. gauge.
This feature could be an advantage in a car if changing altitude, or trying to stretch out a fuel supply. Modern race cars do this to extend their range at times.
The main disadvantage I see is that since an aircraft engine is usually running at a constant rpm between 2500-2700, so there is no provision for an accelerator pump.
Fuel pressure is maintained by a mechanical pump (30-40 lbs.)and starting is accomplished with an electric prime pump. This pump will also feed the engine if the mechanical pump fails.
Shut down of the engine is by pulling out the mixture control to shut the fuel off to the engine. Turning off the engine by spark shut-off will flood the engine.
The engine in the One Design is 360 cu. in. Six cylinder engines are usually 540 cu. in., so there is no problem with the servo handling an auto engine.
Servos that are serviced and signed off for legal aircraft use are expensive, but one that is not should be well under $1000. Nozzles come in all different orfice sizes. As a matter of fact, if you look closely at the baffles on the engine, you'll see a small plaque mounted, that tells what size nozzle belongs in that cylinder, since each cylinder has been combustion measured. That's another story for another time!!
If this system would work, it might not do as well as a modern EFI, but I think it would be better than a carb.
Regards
Jack
How about this:
www.mass-floefi.com/reviews.html
Cheap and easy. No programming. Made for a car.
Cool plane Jack!
www.mass-floefi.com/reviews.html
Cheap and easy. No programming. Made for a car.
Cool plane Jack!
k wright said:
How about this:
www.mass-floefi.com/reviews.html
Cheap and easy. No programming. Made for a car.
Cool plane Jack!
Ken
This is the system that Chris Richards (Mass Flow) and I have been discussing for a retro-fit on our CanAm. All the parts have arrived so we'll be trying the conversion in the near future. One option is to go with his complete SB conversion, or keep the Edelbrock intake manifold, injectors and fuel rails. We're going to start with the latter. If I'm not satisfied with the results, we'll convert back to the 3500 system.
We'll keep you informed of the results. This will be of interest to Edelbrock 3500 system users who are not happy with the operating performance on their Ultimas.
As for the plane, it's the next thing to having your own F-15. I can't out-speed an F15, but I can out-manuever him!!
Jack
USCANAM said:
The aircraft system is a pure mechanical one, using a fuel servo that meters fuel to a fuel distributor known as a "spider". Each cylinder has it's own injector which is mounted in the cylinder head just ahead of the intake valve.
That description sounds very, very much like the Bosch K-Jet mechanical fuel injection used a few decades back on many, many cars.
Bye, Arno.
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