GR-1 Turbojet Project 2/10/04

Posted on February 10, 2004

       I have begun to acquire the parts to build an engine with my design in mind. I started looking for turbochargers that were common and cheap to rebuild in case of a “meltdown”. After some research, I chose to employ a T04B90 Roto Master turbocharger that I picked up on eBay as a rebuilt unit. This style of turbocharger has a flange type exhaust and no internal waste-gate to get in the way. I feel that this smaller size turbocharger will keep my overall building/operating costs down opposed to a monster sized truck turbo.

This turbo has a A/R of .60 on the compressor side and an A/R of .96  on the exhaust side.

       Next I found some surplus rotary vane pumps that will work great for my oil system. These “carbonator” pumps will produce 145 PSI of pressure at 3 GPM. They also have a pressure relief valve that will allow me to set my oil pressure at the pump.

These Rotoflow/Procon  pumps retail for about $80 and do not include the drive motor. I was lucky to find three for $10 on eBay. These are well engineered pumps!

       Next I found a surplus 12 volt DC ball bearing electric motor made by Allied Motion. This motor is rated for 1/4 horsepower at 15 amps. I am going to use it to power the oil pump system. This motor runs at about 5400 RPM so a reduction drive system is needed.

I have got a drive system made for the Procon pump. I used a vacuum cleaner drive belt to drive a pulley on the oil pump that I fabricated out of steel tubing. The drive ratio is 1 : 6 turning the pump at around 900 RPM.

       After having completed the oil pump drive unit, I needed to test it on the turbo. I attached the oil pump to the turbo and ran oil through the turbo bearings to see what kind of pressure this pump could produce. Surprisingly the pump can deliver up to 95 PSI of oil pressure without squealing the drive belt. I tried running heated oil to see what difference in pressure it caused and found a 10-15 PSI loss in pressure. Turning up the pressure regulator will still pump 95 PSI of heated oil so the pump is a success! The drive pulley will also have a fan attached to it to blow air through an oil cooler. My hopes are to keep the engine cool by cooling the lube oil.
       I intend to use an oil filter and oil cooler in line with my lubrication system. A pressure switch will sense the oil pressure and if it drops below 25 PSI a fuel cutoff solenoid will shut down the turbine.                                                           

       I have purchased a number of items that will be needed for the construction including: propane tank, battery and battery box, brass fittings, check valve, solenoid valve, rubber hoses and tubing, turbo flanges, pressure gauges, panel switches, oil reservoir, air filter, ignition coil ,EGT pyrometer and steel for the engine frame.

       I will now have to start engineering the combustor for the turbine. With any luck I will have it together and be ready to test it’s burn characteristics.

Till Later, Don Giandomenico

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