10/8/2007 Project Idea:
As a final machine design project here at SUNY Canton my roommate and I have decided to begin the construction of a jet engine. The Engine will be based on a turbo like many other DIY Jet engines, but ours will be special in that it is a direct through air design similar to commercial engines. It will most likely run off propane and as for what we'll actually do with it, we have yet to come up with a good/safe idea.
10/24/2007 Early Concept:
Some preliminary 3d models of the jet engine.
11/12/2007 New Turbo:
We just won the turbo we'll be taking the fans out of last night from an eBay auction. We should see it in the mail this Wednesday!
12/6/2007 Fans Extracted:
After two weeks, two drill bits, and a lot of bloodied fingers the parts we're actually going to use from turbo have been freed from their old rusty tomb. A little sandblasting and they're actually presentable.
1/29/2008 4 Lathes 2 people:
Work has finally started on the jet! Time for machining was far greater than expected. The tool steel must not get hot for fear of hardening, so the cutting depths have been greatly reduced. The mind numbing boredom we experienced the first two days caused us to begin work on other parts. Between the two of us we are now operating 4 lathes with 4 individual parts, simultaneously.
1/32/2008 First part completed!
the first piece is now done. This part is the front of the compressor area. The hole in the center is where the compressor fan sits. Eventually this part will probably become the fuel inlet plate as well.
2/11/2008 Combustion chamber in progress:
This part is where the expanding propane will contained and directed. This part our first time using a boring tool at any substantial depth. Because the tool stuck out so far from the tool post, an awful screeching sound filled the lab for hours straight. All thats left is the whole for the spark plug and the 4 through holes.
2/24/2008 Total Frustration:
Work on the exhaust has been incredibly slow. The through hole through the center of the part has a 7 1/2 degree taper. Meaning a boring bar must be used to open the ID through the whole length. The part is 5 inches long so the boring bar is sitting almost 6 inches from the tool post. Resulting in an intense squealing sound at anything above a 5 thousandths cut.
After struggling with the shear amount of time it takes to actually open a hole to 2 inches at a 5 thou cut, we finally decided to throw the part up on the mill and remove as much material as possible with a 1 1/4" end mill.
3/1/2008 "Hard Piece":
Rightly dubbed "the hard piece" due to its complexity, part 003 is nearing completion. This piece holds the spindle with both the compressor and turbine fans in place between two bearings. The slots surrounding the bearing pockets are to let the air pass into the combustion area of the jet. The taper of the parts rear is specifically designed to force the expanding gases toward the exhaust end, spinning the turbine.
3/5/2008 Exhaust Completed:
After even more ID boring the exhausts OD can be turned...Finally.
3/10/2008 Bearings And Fans Installed:
The Hard Piece is now completely finished. After review of the system as a whole , we became concerned with the temperatures the bearings might undergo. An oil cooling system has been added, which keeps a constant flow of oil moving through the bearing housing. Better pictures of this will come later on.
The bearings are not nearly as smooth as we would have hoped. This may be due to the bearing holes not being perfectly aligned, or the bearings not being worn in. This issue of starting the engine has become a concern.
3/20/2008 Fuel Inlet:
A fuel nozzle has now been installed in the fuel inlet plate. It consists of a hole on top for our fuel fitting and a threaded cross hole for for the nozzle itself.
3/21/2008 Oil Cooling System:
As stated previously, the temperatures that will be sustained by the bearings have us worried. So, as an excuse to buy some 10 dollar made in china bearings (instead of 200 dollar ceramic ball bearings), an oil cooling/lubrication system was implemented.
4/3/2008 Jet Engine Nearing Completion:
The jet engine is now almost complete and assembled. The Spark Plug hole has been drilled, and the nose of the jet is now complete. Threaded rod threads into the nose and all other sections slide over the rod. The assembly is held together by 4 nuts. The joining faces on each section have been ground as to ensure a seal. Work has also begun on jet engine base. Another group, in charge of the instrumentation, and mounting, has constructed a stainless steel box on which our jet engine will sit. The inside of the box will contain our ignition system and oil cooling system.
4/10/2008 Ignition System:
Quick and dirty ignition system. An arduino is used to generate a square wave which is being fed to a mosfet driving a jet ski ignition coil.
4/21/2008 Jet Engine Test Stand:
With time running out at the end of the year, we passed the stand and instrumentation onto another group, for their final project. So for everything not previously documented in these pictures, credit goes to them.
5/4/2008 Jet Engine Testing!:
Some initial testing how now been done, both with and without the oil cooling system running. We have run into some issues with the friction in the bearings, but are still hopeful this can be overcome with more fuel.