DIY Turboshaft Kart build for the University of Kansas

[Feathers]

Not that this needs any explanation, but



It runs! We didn't get anywhere near full throttle, and it's scary. These were the first drives, I'll post video of later testing and full throttle runs.

Cheers,

Feathers

[racket]

Hi Feathers

Thats such a nice build :-)

You'll be pleasantly surprised once you give her full power .

Looking forward to seeing more

Cheers
John

[Johansson]

Awesome Feathers! The cart will fly down the road when you crack the throttle up fully.👍🏻

[Deleted]

Wonderful...... real nice work :-)

[Feathers]

The team have buttoned up a few more items and have been flirting with with full throttle.

That said, full throttle is a conservative 60krpm max N1, and the NGVs are still flowing much more than we calculated optimal for the power stage.

That junior chassis sure looks silly with college students driving That's what we intended all along...



The FADEC runs a constant slew limit on throttle input, which has to be fairly conservative to avoid a flameout. Consequently, at high throttle values where the high slew isn't necessary, it causes the throttle to "stick" for about a half a second. We'll fix this by implementing a slew rate curve that follows throttle.

It truly is terrifying because this turbine seems to be on it's way to a sweet spot as the kart accelerates. So not only does it keep accelerating, but acceleration increases as the kart speeds up.

The team will surely have more updates as time goes on. I just can't wait till I'm driving it again!

Cheers,

- Feathers

[racket]

Hi Feathers

Yep , they start off a tad slow then the power builds quickly as we start to convert the freepower's high starting torque into horsepower when the "distance" component from blade speed increases, its horsepower that produces acceleration , torque doesn't do anything much unless the turb wheel is spinnng ................my 2 shaft kart started to produce a strong "push in the back" once up to ~50 mph-80 kph , turbine engines have a nice F A T power curve .............you need a bit longer length of tarmac to let her loose :-)

Cheers
John

[monty]

Somebody with a heavy foot needs to drive that thing on a loooooonnnnnnnggggg piece of asphalt somewhere....

Install a FOD screen first though..

Monty

[Deleted]

wonderful get it on a long road now and let it rip

[Feathers]

Unfortunately no letting her rip yet the power turbine has not been properly balanced and it needs clean bearings installed (these are a bit "crunchy" from 4 years of assembly and disassembly in machine shops).

The team have been adjusting the throttle slew rate code which keeps jittery fingers on the throttle from flaming out the engine. They've got it pretty well dialed in at this point. They have also been programming a useful interface for the steering wheel I designed for the kart years ago, it has an integrated OLED (self-illuminating pixels for visibility) display, and some SUPER bright "neopixel" RGB LEDs arranged in an "arc" above the display. The RGB LEDs aren't working now, but should be a very, very clear indication of whatever we want them to indicate.

The member advising on the steering wheel display spends his days programming avionics for Garmin, so as you'd expect it is professional and aircraft-esque:



And here's the steering wheel as-designed:



Finally, here's a video of the new display in action. Camera is tilted down so the team can watch afterward for slew/display performance. They'll have some regular forward-facing video soon:



Cheers!

- Feathers

[Feathers]

Can't believe it's been so long and I haven't posted this yet! Full video below:



Still a work in progress. Unfortunately the group that built her is beginning to dissolve. I might borrow it for a while to perform some needed upgrades.

At work, I have access to a >$1M DMLS 3D printer which we use for Inconel and stainless steel parts. The hot components of the engine are a little tired, as they're all 304 or 316 and have been running yellow-hot for cumulatively many, many hours now. Once I've got it back, I'd like to tear down and rebuild the hot section with a 3D printed Inconel 718 evaporator assembly and combustion liner. Those should last longer than anything else on the chassis.

Looking forward to playing around with this thing some more.

Cheers,

- Feathers

[racket]

Hi Feathers

Nice to hear the kart is still active and that you're getting on with your career :-)

Did you end up with any performance figures ??

Cheers
John

[dieselguy86]

It's awesome to be able to watch something like this "happen". Sure gives me some inspiration to get my bike engine built. Speaking of, what would be the chance you could 3d print a turbine wheel or if inco? Only 105mm diameter, already modeled, and I've pla 3d printed a few prototypes. Just thought I'd ask. My other option is sending to a specialty foundry that can cast from my model, but a printed one would be cool.

[turboron]

Feathers, my experience of a few years ago, is that 3d printed stationary nozzles/vanes were being used in prototypes. I believe that GE reported they had built a axial turbine rotor with 3d printed blades. A Google may show you the state of the art.

Thanks, Ron

[mecarloschavez]

hello guys such a cool build any guess on the HP rate?