Preparing for atmospheric testing

This is my test setup for the combustor. The shop vac at the top of the picture will supply air to the combustor for this test, since the turbo will not be installed. This test allows me to see the results of my hard work, as the burn process will normally be contained entirely within the unit and will not be visible.

The combustor works

With the air supply to the combustor on low and the fuel turned on, I lit the combustor and it worked. Raising the fuel pressure and airflow at the same time made the combustor roar.

Fuel delivery and ignition

The fuel enters the combustor from the side through the braided stainless hose, and the red wires are temporarily attached to the sparkplug used for ignition.

Blast shield

As you can see here, I had to use a shovel as a blast shield to keep the hot gasses away from the hose supplying air to the combustor. Note the duct tape in the photo, which is an essential supply in any shop.

Nice flame from combustor

I turned the lights off to get a better picture of the combustor in action. The flame coming from the combustor made a roaring sound, and would suck a little further up into the combustor with the addition of more air.

Cone of fire

It works! The combustor puts out a lot of heat and noise. The rush of air leaving is much greater with it lit than with just the air supplied by the shop vac. It should work with the turbo installed.

The flame tube

With the flame tube above, the engine wouldn't work and kept flaming out. I closed up the air holes and drilled them out smaller and that seemed to correct the problem, however, it would run hot and the turbine housing would glow red. I made the end of the flame tube flare out and drilled holes in the flares to allow more cooling air to come through. This extra dilution air helps to cool the air entering the turbine scroll and seemed to work somewhat.

Making the flare

To make the flare I cut the end of the flame tube into sections that could be bent out.

Filling in the gaps

After flaring out the pipe, pieces of steel were brazed into place to fill in the gaps at the base of the flame tube.

The new nozzle opening

I found that the original nozzle opening did not work as I had expected. I made a new opening that is simply a hole through which I can inject the propane fuel.

Ignition system

The ignition system I built for the engine is nothing more than a flasher, condenser and ignition coil from a car (the ignition coil is not in this photo). Although simple, it works and provides enough spark to get the engine running.

Another flame tube modification

After more testing, I decided to make additional modifications to the flame tube You can see the much improved flare at the end of the tube.

Cooling air slits

With the new flare in the flame tube, the cooling air is supplied through the slits at the bottom.

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