VT-50 Jr. Dragster (kindof)

[Feathers]

Chris,

I've only measured 1-1.5 volts drop across the controller, I think these larger mosfets will solve my problems

And a PWM solenoid injection system would be a really interesting way to throttle an engine. I might look into it if I get sick of throttle cables and linkage troubles! Has it been done before?

Thanks,

Feathers

[wolfdragon]

I am working on making a fuel injector work for my combustor, as I plan to use gasoline instead of diesel or kerosene, this was a straightforward solution for what to inject with. Still working on the controller but basically the 12v saturated type injectors can be easily driven with a specific chip (designed fir that job) and the chip only needs a PWM controlled pulse input to it.

I will post something as I get the bugs worked out, bug hurdle is finishing my GT and verifying the numbers for fuel consumption.

[racket]

Hi Wolf

Don't use gasolene , kero has better combustion characteristics and is a lot safer to use .

Cheers
John

[wolfdragon]

unfortunately the desired end use pushes me burn to gasoline, I have an off road vehicle that is in serious need of an APU, they need to drink the same fuel

and when I'm done hopefully I will have something to put forth as a do/don't for running gasoline

[racket]

Hi Wolf

Mmmm, in that case its understandable , some of the aero jet fuels are getting closer to gasolene rather than kero so it will work , just have to be more safety minded due to the volatility , it'll be interesting to hear about any potential combustion differences :-)

Cheers
John

[Feathers]

I got my IRFZ44N 50 amp mosfets today!!! Happy!!!

[turborico]

If you're going to use gasoline, make sure you have a good fire suppression system... automatic would be pretty nice.

[wolfdragon]

automatic C02 deluge system, already designed and budgeted for

[Johansson]

Any more progress on the build?

[Feathers]

I know I haven't posted for awhile, but I've done some work on the engine, and its running like you wouldn't believe!

Heres a video:

youtu.be/bMWFkr24tdI

It runs on diesel nicely, and runs nice and cool. Only thing is, if I run it up to 15 lbs boost, the silicone elbow that connects the compressor outlet to the combustor inlet starts to slip off, so almost every time I throttle it up, it comes loose and I need to shut it down. That little annoyance asside, I'd like to share my ambitions for this engine.

Thrust power would be fun, but I think that a turboshaft putting out 130 HP would be a lot MORE fun.

I'm no master machinist, so I don't know that I'd be able to make my own N2 stage, but the stage off of the JFS - 100 seems like it would be perfect, already having reduction gearing and such. I'd just need to make a new splined shaft and a shaft tunnel with a bearing to support lateral load from a chain to a clutch mechanism or some wheels.

Only thing is, I need to be mindful of my spending! I need to speak in terms of hundreds, not thousands, of dollars. I've been looking, and it seems like these power turbine sections go for around 2,500 USD in good, tested, used condition.

I am open to alternatives if procuring a JFS-100 part would be too expensive, but just don't know what to do!

P.S. I don't want to do things RCDon style. While he is basically an engineering genius, I don't have enough time or balls to fabricate my own turbine!

Thanks for all your help so far guys! It's made this project possible.

[Johansson]

Hey Feathers!

I was waiting for an update from you, good job with the engine!

Why not make your own power turbine section? Did you see John´s cart with a large radial power turbine directly coupled to the rear shaft by sprockets and chain? It moved like the devil even though he had to dump some of the exhausts since the PT wheel was too small.

With an axial power turbine wheel made from a 5mm stainless sheet and revs kept at moderate levels you should get some impressive power figures from the engine, a JFS PT section is probably very difficult to source for reasonable sums of money if you don´t find someone that likes your project and has a spare one that he can live without.

Are you going to start fitting the engine to a JR dragster frame now?

[Feathers]

I did see it!

I have a friend with a large engine-style lathe that I could use to cut a new bearing-core for to fit a turbocharger's turbine scroll and hold the turbine wheel... I'd just want to find one large enough to utilize every cubic foot of exhaust gas leaving the engine and make lots of power!

Has anybody made an axial power turbine like you described? I'd love to take a look at it!

I've also been looking at John's setup with the bike.

The only issue is, I'd need to find a reasonable reduction box if I went axial, and I'd need to fabricate the nozzle/stator vanes too. Lots of work. This is why the JFS-100 section is particularly appealing. You've probably already seen it, but the guys at
www.turbinebuilder.com
have already used this type of setup. I would just make it smaller, lighter, and closer to the ground. The engine would be mounted sideways, with the rear axle underneath or behind, and I would build a spot for me up front from square steel tubing, just like I welded up the engine frame.

I've been asking around, and have spoken with Paul Stender on the phone, and gave him my email. He said he might have a unit which had a bent flange, preventing proper fit to an engine, that I would be able to use. I'm waiting to hear back for confirmation and a quote on that little jewel.

So I'm hoping for the best

[racket]

Hi Feathers

Just been checking out the video , nice build :-)

You won't get 130 hp from that gas producer , its flow isn't sufficient , probably 60-80 hp .

Matt at "turbinebuilder" had other issues with the build that restricted its full potential , we did a lot of PM'ing on that build .

The JFS is probably not the best unit to use as its output rpm is relatively low which then requires stepup gearing .

Theres info in the RoTs on DIY Site for a freepower to fit your size gas producer .

A garrett TV94 sized turb stage would be big enough for you if equiped with a 1.70 A/R housing

I used a homemade freepower on my turboprop PJ , www.youtube.com/watch?v=uqMn0A2aUdo it went to >20,000 rpm , I think theres pics of it in my Rackets photo folder on DIY

Cheers
John

[Feathers]

Hey Racket,

Just curious, isn't that garret TV94 what you used as a gas producer for your jetbike? That things a monster! Wish I'd have used it, maybe then I /could/ reach into the hundreds of horsepower
How many HP did you end up getting out of that thing?

At 3000 RPM (around 60K for the power turbine wheel), (at 1:1 with an 18" golf cart tire) Simple algebra says I'd be going 160mph (not gonna happen with 80 hp) so maybe a little under 2:1 sprocket ratio would be necessary for the JFS-100.

As for the radial option, I'd have to track down a tv-94 turbo, and machine a replacement "core" to hold the bearings and mount the unit. Could be simple enough...

What did you end up doing with your turbine bike? I noticed you used a separate gearbox and made a turbine housing for an axial turbine, but past that I wasn't sure. Did you use a nozzle/stator vane setup?

Thanks!

[Feathers]

Some of the parts used for the evap system. Freshly finished with my new belt sander