Turbofan Jet Engine

My love for turbines continue, I'm building this model (still a lot of parts to print yet). Also, experimenting with rattle-can painting of PLA, seems to take quite well:

http://www.thingiverse.com/thing:114468



Next year I will do the much needed overhaul on my baby:

..........My Bergen Intrepid Turbine with Wren MW-54H Engine

 

Thanks! ....the parts-fit is superb!

 

Inter-stage/bearing alignment using R/C heli mainshaft .....
still have to go buy a 10 x 220mm shaft. All the big stuff printed very easily, now on to all the little compressor turbine wheels.

 

Here it is, no ordinary business-card holder:

 

.........and here's the spool-up!

 

Holy hell that's awesome. What are you using I drive it?

 

LOL!
Shop-air at 100psig .....had the N2 stage all the way up to 20k RPM and it ran well, but I felt I was pushing my luck! ....will keep the demos to around 10k as that seems like a reasonable speed for it.

 

Is there like a clutch or something?

 

Nope! .....just the air-jets against the turbine wheels ....and when you tweak the jet angles and the flows just right, it starts and runs sequentially (N2 then N1) just like the real deal .......you gotta understand, I just love all things Turbine! ...hahahaha!

 

Wife thinks I have too much time on my hands!

 

I think you might...

Then again not many people have a 3d printed turbine engine that actually spools up like a real one.

Mind if I share that video on the google+ 3d printing group?

 

Go right ahead! ...people need to realize the full potential of what we can do with this printing technology!

 

Awesome!! Now, mount that puppy!

 

Been asked this a few times, so here's a good explanation of the startup process by K. Aainsqatsi and found on Wikipedia:

Turbofan basics
Refer to the image below (Credit: K. Aainsqatsi, Wikipedia):

​

The portions of the engine referred to below are:

• The N1 fan, N1 shaft and N1 turbine which are displayed in green and labelled "Fan/Low-pressure compressor", "Low pressure shaft" and "Low pressure turbine". These units are connected and move as one piece.
• The N2 compressor, N2 shaft and N2 turbine, displayed in purple and labelled "High pressure compressor", "High Pressure shaft" and "High pressure turbine". These are connected and move as one, but independently of the N1 shaft. Un-pictured is an accessory drive that is geared to the N2 shaft to drive engine accessories.
• The hot section, pictured yellow and labelled "Combustion chamber". This is home to a constantly burning fire in a jet engine.

Engine Start
The process of the engine starting follows this basic formula

• Through the opening of bleed air valves, bleed air is sent to an air turbine starter. These devices typically use the high pressure bleed air to spin and engage a centrifugal clutch connected to the engines accessory drive. This in turn causes the N2 shaft within the engine to spin.
  
  
• With the N2 shaft spinning, the N2 compressor and the N2 turbines are spinning. This begins to force air through the engine from front to back.
  
  
• With the accessory shaft and N2 shafts spinning, accessories should start working and this can be verified by oil pressure indications on the EICAS.
  
  
• With increased N2 rotation, ignition will be turned on. These igniters are located in the hot section of the engine and produce small sparks. There should be an indication on the EICAS that the ignition is active.
  
  
• With further increase in N2 rotation, fuel flow will be introduced. This will be verified on the EICAS. Once fuel flow is noted, it is important that the next stop happen fairly soon.
  
  
• Light off! The fuel is lit by the ignition and now the fire burning in the hot section supplied by air from the compressor is producing thrust across the N2 and N1 turbines.
  
  
• As the engine is producing thrust across on the N1 turbine, the N1 shaft is spinning the N1 fan and the EICAS will note this increase in N1 rotation. N1 and N2 rotation speeds increase.
  
  
• Above a N2 threshold, bleed air valves supplying the the air turbine starter will close and the starter disengage. The igniters will turn off at some N2 threshold.
  
  
• The engine will settle into a stable idle thrust setting.