GR-1 Turbojet Project 3/7/04

Posted on March 7, 2004

       I have been busy testing the GR-1 and would like to post my test results. I set up the engine on rollers so I could measure the static thrust and hooked up my frequency counter for RPM measurements. I based my measurements relative to my combustor or “boost” pressure staring at 1 PSI moving up to 15 PSI of boost. I do not have a flow meter for fuel yet so I will have to do that research at a later date.

       The barometric pressure was 30.25 inches and the temperature was 71 degrees Fahr. The propane tanks were producing an average of 65 PSI of pressure. The oil pressure was at 42 PSI and steady at full operating temperature. The chart below shows four columns; #1 PSI “boost” or combustor pressure, #2 RPM of the turbine, #3 pounds of static thrust and #4 the exhaust gas temperature in degrees Fahrenheit.

     PSI Boost            RPM              lbs. Thrust        EGT Fahr.

1

40500

1

980

2

47000

1.75

975

3

51500

3

970

4

56500

4

965

5

64000

5

965

6

72000

6

965

7

78100

7.25

970

8

81200

8.25

980

9

83400

9

990

10

85400

10.5

1000

11

88200

12

1005

12

92000

13.25

1010

13

99700

15

1015

14

112900

16.5

1015

15

126000

18

1020

RPM of turbine

PSI “boost” or combustor pressure

Pounds of static thrust

PSI “boost” or combustor pressure

EGT Degrees in Fahr.

PSI “boost” or combustor pressure

       It appears that the GR-1’s combustor is a decent success as that the highest exhaust temperature was 1020 deg. Fahr. (548 deg. C).  The turbine spooled up to 126,000 RPM at 15 PSI combustor pressure and did not overheat. I feel that the turbine is running at about 80% of it’s full potential and I am not going to push it much farther. The exhaust nozzle seems to be at the right diameter as the target RPM is met with the target combustor pressure of 15 PSI. The GR-1 is running very reliable and stable so not much needs to be done to the engine as it stands.
       The next step in the GR series is to start researching the “free-shaft” turbine project so I can harness the power of the exhaust gas to turn a drive shaft. The free-shaft turbine will be a little harder to design as I will need a gearbox that can handle high RPM. I will also need some type of turbine wheel system to harness the exhaust gas. I look forward to getting into this project in the near future.

Until next time,

Don Giandomenico

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