Advanced FWE plans right here in PDF

[James D]

I know this is a real old thread but what the hell, call it recycling.

Eric I built an advanced FWE to your plans a couple of weeks ago and it runs great, really awesome.
I just wondered if you could give me some pointers on how to get it running on liquid fuels, I was going to try something similar to that shown on the Laird Chinese plans but there are lots of possible variations of placement and pipe size.
Any help would be appreciated.

[Eric]

NICE!

If you have some more pics and a video of that I will make you an entire gallery page on my site!

Eric

[Eric]

Ok here is a diagram showing a simple way to find the best fuel injector spot. Doing so you will also get to play around with water injection!

If you can offset your propane fuel injector to the side a little bit it will help things out.

Basically you take a small metal tube, small hobby coper tubing is good since its easy to bend.

Bend the tip so that it is at 90 degrees, and the tip of the injector would be positioned in the center of the intake, bend down the line so that it goes off to the side that way you have something to hold onto.

Connect a piece of rubber fuel line to the metal injector tube, and make a twisted wire type clamp, tighening it down with a small wrench.

now all you have to do is put the end of the hose in a bottle of water, get the engine fired up, and put the tip of the injector into the intake and move it back and forth.

There are some spots that will pump a ton of water if you let it, and others that will blow a ton of water out the intake, you dont want the injector positioned where it will blow excess fuel out of the intake so find a good spot that pumps well, and does not blow excess water out the front.

Get a few small tubes and try them, Nothing bigger than 3/32 nd. 1/16 should work well.

Depending on the diameter of the tube and how well the water is atomized, you may get a really really high flow rate that can stall the engine. Make sure the rubber fuel line is long enough that you could have it go onto the floor and have a partially clamped down vice grip on it which will limit the flow area. With a little bit of experimenting you can get the flow area limited to a very stable level.

Once you find a good position, and have a reasonable flow rate, try the same setup with some liquid fuel.

This time have the engine running on a low idle and quickly insert the injector to the position you found before, making sure that you dont let it spray the liquid fuel all over the place.

If it quits you are giving it too much fuel, tighten the vice grips down more and try it again until the engine continues to run after you insert the fuel injector.

Since you will actually be injecting fuel now, you can immediately hear the difference when you hit a good spot for injection.

You will be able to hear the engine "lean out" or "get rich" . When it leans out or gets rich it will have reduced thrust, basically the louder the noise the more thrust you are getting. And there are other spots that run really rough because they might be blowing a lot of the fuel out the back.

Once you find a nice stable smooth running spot that doesnt blow any vaporized fuel out the intake, turn down the propane fuel flow slowly.

See if you can get the engine turned off of propane and completely running on liquid fuel. If it quits you might need an area of slightly higher fuel pumping, or to open the vice grips up slightly

Once you get an area that lets the engine run continuously on liquid fuel with good power development (like I said earlier you will be able to hear the difference in power as you move it around, the louder the better, as long as it is a smooth kind of loud and not a rough chaotic kind. )

Once you get a good spot that runs smooth, and that has a decent liquid fuel throttle range (vice grip "needle valve") make a very careful mark where the fuel tube is at the front of the intake so you can measure exactly how far into the intake it is.

Once you have that measurement you can drill and tap a small hole in the side of the intake, tap it for a 1/4 20 thread, or even 10-32 like a dynajet metering jet would do.

To make an injector for the engine just take a piece of brass hexagonal bar stock .25" diameter and machine down the tip and tap it, and put a part on the outside to connect a fuel line to.

Drill it out most of the way with a 1/16" drill, and drill the tip with a .032" hole.

You should probably thread the outside end of the fuel injector, so you can tap the inside of a metal tube that can be used as an extension pipe, which can be bent down to any shape you want in order to get the rubber fuel line far away from the hot engine.

Now you should have a liquid fuel injector that limits the fuel flow to the necessary levels, and that you probably wont need a needle valve to limit the fuel with.

Put it in the engine and fire it up on propane, transition to liquid fuel operation and then shut it down, remove the propane injector, and try starting it up by blowing compressed air right over the very tip of the injector.

You should have a very nice little liquid fuel powered valveless.

Eric

[James D]

Thanks Eric, I've got some 1/16" copper pipe so I'll probably give it a go next week, Should be good fun.

I might also try and take some thrust measurements when I add the water and see how much difference that makes, At the moment its showing just over 2lbs on my cude setup.

Thanks again for taking the time to reply Eric, I will email some pictures and video for your site.

[James D]

A short video clip

[Eric]

That is a really great looking engine.

Once you get a better test stand made up for measuring thrust if you are not getting 2.25 you could probably tweak the intake flare a little bit.

You can get some pretty big gains in thrust with water injection.

Eric

[Mark]

I like the sound of it catching, that near "instant full grease" sound, just the whistling air feed and then bang!
Mark

[larry cottrill]

James -

Nice FWE build, and nice videos of starting & running! Sorry I'm a little late in saying so ...

Good work!

L Cottrill