The time has come to start mounting the equipment into the frame. After getting all of the mounting locations worked out, I painted the frame and engine parts in preparation for final assembly. Mounting the parts should be easy now with only the task of plumbing the hydraulics and wiring the electrical system. I started off with the oil tank/heat exchanger that mounts just below the turbine oil drain.
The oil pump, oil cooler and filter were next on the list and all were fastened in place. I used transmission oil cooler hose to connect the lubrication system together. Hose clamps keep all of the lines in place.
The order in which the hydraulic system is plumbed is as follows: Oil tank > oil cooler > oil pump > oil filter > turbo > oil tank. I run the suction line from the top oil cooler fitting to the oil pump as to help clear out any air accumulation in the cooler. Air bubbles will consolidate in the cooler tubes forcing the oil to trickle down the tubes instead of filling them completely. This condition will not allow the oil cooler to work efficiently. Feeding the oil pump from the top oil cooler fitting will naturally pull any accumulating oil bubbles out of the cooler.
The lubrication system is now in place. Notice that the oil pump has a cooling fan to blow cool air through the oil cooler
The combustor is assembled and mounted into the frame.
The ignition system is mounted and the DC motor that drives the points is mounted into a aluminum box. The wires are loomed up to the control panel.
I installed the gauges which indicate oil pressure, line fuel pressure and combustor/compressor pressure. I plumbed these gauges with 1/4” nylon tubing which was very clean and fairly economical. I put the throttle valve together which features a check valve as to not allow any pressure from going into the propane tank. I also used a quick disconnect fitting to hook the propane tank to the engine. I welded a set screw mechanism to the throttle valve so the idle speed can be set. This should help in starting the engine.
Note the throttle valve on the left and on the frame on the right.
I am now ready to mount the turbocharger onto the combustor. It is starting to look good now with all of it’s tubing and hoses run.
I decided to add an “inducer ring” to burn of the vented oil vapor from the oil tank (as seen below). The ring is just a short piece of 2-1/2” EMT that is attached to the intake of the turbocharger with a silicone hose coupler. The ring has a hose barb installed into the side of it which is attached to the oil tank vent line. The suction of the inducer will create negative pressure in the oil system and lower the oil loss from the seals in the turbo. Running the vent line into the engine’s inducer will also help keep the vent line from “smoking” when the engine is running.
Note the blue silicone hose that attaches the inducer ring to the inducer of the turbo. The hose on the side is attached to the oil tank vent barb. I also installed the battery into the frame.
The control panel was designed to shut down the engine if the emergency stop button is pressed or the hydraulic system looses pressure. In the event that either one happens, the fuel solenoid closes and kills the engine. The oil pressure sensor is set so that if the oil pressure drops below 25 PSI, a relay will close and latch which closes the fuel solenoid. Only by resetting the fuel circuit can you get the fuel to flow again. An alarm sounds when the E-Stop or pressure sensor is tripped notifying the operator. The pyrometer is also put into the control panel to help in starting the engine. After testing the operation of the control circuits, I installed the rest of the equipment to complete the engine.
The finished control panel looks good! I labeled the gauges and switches for a final touch.
All of the tubing and wiring is in place and the ignition system is working great.
I filled up the oil system with 5W-30 Synthetic motor oil. The synthetic oil should be a good match for this system. I had to run the pump a few times to get the trapped air out of the oil cooler and filter.
I can barely handle the anticipation of running the completed engine as I bolt on the tail pipe. The finished product is looking good and even if it doesn’t perform as expected, it will still be fun to look at :0)
I messed around with the oil pump to set the pressure at 50 PSI to keep the bearings happy. I then pre-tested the leaf blower used to spool up the turbine (turbo) and it seemed to have the power needed. I was now ready to start the turbine. After checking the systems out I started the oil pump and verified my oil pressure. The control panel indicated a green light on the oil so I fired up the leaf blower and spooled up the engine.
I turned on the fuel circuit and then the ignition circuit to hear a pop inside of the combustor. Well, it was more of a small boom as I felt it on my pant legs. The turbine did not spool up, instead there was a fire ball out of the tailpipe and my pyrometer was pegged at 1600 degrees. I shut down the fuel and cooled off the turbine for a minute. I guessed that there was so much fuel that it could not be contained in the combustor and traveled into the exhaust nozzle. I wanted to try again with less fuel so I turned down the idle screw to just a small hiss of propane. I ran up the leaf blower and lit the combustor with a poof. The temperature was remaining at 600 deg. Fahr. and it was not spooling up any faster so I cracked the throttle a bit more. The turbine started to whine higher and higher as I pulled the blower away from the inducer. The exhaust temperature was running about 1200 deg. and falling as the turbine spooled up. It was running!!!!!!!!!!!!! I was fairly amazed at this contraption taking life onto itself. I just had to throttle her up so I eased the valve open and she started to sing. The noise was deafening as the combustor pressure leaped up to 12 PSI and the roar of rushing wind was awesome. I ran the engine for a few minutes and shut her down to repair a few oil leaks in the hydraulic system. I fired up the turbine again to take note of my pressures and temperature. The exhaust gas temperature was running about 950 deg. Fahr. and even got a little bit cooler at higher RPM. The combustor was a success and the turbine ran like a top every time. I am now working on a better fuel supply as the 5 gallon LP gas tank cannot evaporate the fuel fast enough to feed the turbine. I need more fuel pressure or to convert the turbine to diesel fuel so I can get some real thrust out of this baby. As of now I am only getting about 18 pounds of thrust with this exhaust nozzle but I hope to get more with some modifications.
This is a shot of the GR-1 running at the RC model field with a smoke oil injector in the tailpipe. We made some cool clouds of smoke.
I am really happy that I got the engine running with minimal setback. I have achieved two of my three goals with the last one still to be designed and built. I intend to experiment with a “free-shaft” turbine system later on so I can make the engine self-sufficient by adding a turbine generator. For now I plan on doing more testing on the engine’s current configuration. I plan on documenting the thrust, temperature and pressures in later posts. I also plan to post the GR-1 Combustor Formula that I am working on for other enthusiasts. I am not done with this project so check back later for more developments.
