The OSU Turbojet Project

Turbo-Charged 2.0

osuturbojet — Sun, 23 Aug 2009 18:09:41 +0000

So the turbocharger finally arrived, after waiting several days for the person to ship it. Anyway, I measured the inducer and exhaust, and came up with roughly 1.75″ for both. The compressor outlet is about 2″. It’s in good condition, with no end play and slight side play in the shaft, and all of the blades appear to be in good condition. Looks like it will work out for us.

Turbo-charged

osuturbojet — Sat, 15 Aug 2009 14:10:43 +0000

So, after looking aroung online for a couple of weeks now, I finally stumbled accross a turbocharger that both meets our needs and would be cheap enough for two college students to buy. Unfortunately, I was outbid at the last second. That’s ebay for you.

Luckily, I happened to discover another turbo the next day, in better condition, and still at a reasonable price. Even better, this one had a “buy it now” option, which the seller informed everyone that he would throw in some oil and coolant lines if purchased by those means. I was already leaning towards buying it outright anyway (seeing how the last auction worked out for me), and this tipped the scale fully, you might say.

Long story short, Mike and I are now the owners of a Garrett GT-25 turbocharger, which should be arriving sometime this next week. Pictures will be coming soon after. Let the madness begin!

Lots of Info

osuturbojet — Mon, 27 Jul 2009 08:51:38 +0000

So, since Mike is interning somewhere around Pittsburgh and I’m hanging out in Columbus, the project is going to be slow to get started. For now, we’re basically doing a bunch of research, hoping to get some ideas and/or tips so that maybe, just maybe, we can get this thing to work on the first try.

I guess I should mention what we’re actually going to build. We’re making a turbojet engine, in a sort-of unconventional manner. Acting as the compressor and turbine will be a turbocharger from a vehicle. At this point, we’re looking at purchasing one from a junkyard. The rest of the engine, including the combustion chamber, nozzle, etc. will be fabricated.

In doing some research, I discovered that although these engines are small, they can be quite powerful if built properly. Some of the nicer ones I’ve seen produced upwards of 60 pounds of thrust running with propane as the fuel. The typical rpm range for the turbine at full throttle seems to be between 50 and 75 thousand. Although this speed is well within the mechanical limits of most turbochargers, precautions must be taken to ensure the turbine blades do not melt or break…..things breaking at 75 thousand rpm is definately not going to end well.

I was originally thinking about using an intercooler between the compressor and combustion chamber to reduce the air temperature, but I think we might wait to see how much the compression actually affects it before spending the money on one.

Because we are aerospace engineers and, well, guys, we think afterburners are sweet. So sweet, in fact, that we will be attempting to incorporate one into our turbojet design. I’m not sure if this is entirely accurate, but I read somewhere that the effect of an afterburner on thrust output is roughly proportional to the ratio of exhaust temperatures across the afterburner. More plainly, if the afterburner causes your exhust temperature to double, the thrust output should roughly be doubled. Again…..sweet.

I’ll finish off this post with a 3D model I was working on of our design. It includes an intercooler, although I mentioned that we might not use one. Also, I’d like to point out that none of the parts are actual sizes. They are close to what we would be using, but all I was really making the model for was to visually get an idea as to what the final product might look like.

3D Model