Grants Turbine Kart

[GrantB]

I really wanted to put my Tiernay into something that i could ride and all of the turbine karts on here didn't help. A few weeks ago i was looking at the FIA distance records and looked at the Turbine category. The farthest distance they have in the books is 1 mile and since im pretty sure i could get a turbine contraption to go farther than that i knew i had to get moving.

I bought this kart a few years back but never really did anything with it so it just leaned up against the wall in the shop.

Right now the plan is to use a Harley Davidson transmission and clutch near my right shoulder. Still have to figure out if this will actually work or not.







So far just made some sleeves that will slide into the kart and allow me to weld a little sub frame on the back for the engine. There will be tabs with turnbuckles also to hold them in place along with supports on top of the engine to ahead of the axle to help combat chassis flex.

This kart went 110mph at daytona with a 15hp engine. This thing should make atleast 80hp from what i gather so it might be a little overpowered

[Johansson]

Sweet build!

[racket]

Hi Grant

What horsepower do you have ??

What ouput shaft rpm ??

Why not a centrif clutch www.noramclutch.com/centrifugal-clutch/ and a direct drive without gear ratios .

Cheers
John

[GrantB]

The turbine is listed as 80hp which is more than i really need and a max operating speed of 12,000rpm.

I looked for a while for a higher hp/torque centrifugal clutch and once you get above 20hp it seems like the become industrial sized and really big and expensive. They also lock up at 1-2k rpm's which can be changed but i don't think enough or safely operated up to 12k rpm's. Jack shafts can be used to get the rpm's down but then i'd probably have to run another jeck shaft to bring rpm's back up. Its probably the best way to go but im a glutton for punishment and i like the idea of being able to test it out on smaller tracks/roads at lower speeds.

I also worked at a karting center for 2.5 years and got really good at rebuilding and tweaking clutch baskets and steels on the honda 270 engines and would rather not use one but could build a custom one if need be. (this would probably be the best in the long run) But whats more fun than a turbine go kart? Shifting a turbine go kart!

[Johansson]

I think you might have some problems with a gearbox, with the gas turbine at full throttle and a gear change coming up you would over-rev the freepower the instant you press down the clutch. Some kind of brake on the output shaft could be used during gear change but that way changing gears would take forever.

What about a variator from a snowmobile? Lightweight, cheap and built to handle way more power than 80hp.

[racket]

Hi Grant

Is the engine a single shaft or a two shaft with a freepower turbine wheel , gensets are generally only one shaft engines which makes things a bit difficult for powering a vehicle as theres virtually no power below 50% rpm .

Could you point me to the Link you used for the specs

Cheers
John

[GrantB]

The gearbox im looking at has dog rings that can be shifted without the clutch. I'd like to use the clutch to get rolling in 1st then let off the throttle pull into the next gear, all the way up to the top gear. Downshifting will pretty much be pushing in the clutch and putting the trans into the appropriate gear or neutral. With a syncro trans i think you would be correct assuming i didn't de throttle first. Im planning to use an arduino to control the fuel injection so i'd probably also have a hard fuel cut at maybe 12k rpm's or something lower to prevent an over run.

The Tiernay Turbine tt10 is rated at 80hp @12k rpm in the service manual that i will try to host later on. Here is a link (not sure why i had to translate it) with the same numbers.

translate.google.com/translate?sl=es&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fesp.ebay.com%2FviewItem%3Fitem%3D160846309201%26v%3Dgbh&act=url

I have read that you can add a second set of injectors for roughly twice the hp. Im not sure how true this is since i have seen so few of these online. Im sure you can figure out how much power it can roughly make based off of the dimensions.

Let me also say im really new to turbines so half of what i want to do or say is probably incorrect and this will be a learning experiment for my gas turbine assist project that John has been really nice to help me with.

[ernie wrenn]

GrantB

Don't worry... ask any questions you need, that is what we are here for. We have ALL cooked parts and found out a better way. Now I ask first and then burn the parts..

Ernie

[Richard OConnell]

I would recommend a turbine brake connected directly to the clutch by a mechanical means. If your cutoff used a solenoid, the noid could hang and render itself useless. There is also the possibility of getting fuel on your overspeed control and causing it to malfunction.

I foresee your problem with potential overspeed being your most difficult challange to overcome. Whatever your solution is, it will require regular inspection.

Good Luck!

EDIT: Haha, just thought how cool it would be if someone came up with a centrifugal brake design, though it would take a tremendous amount of precision to build.

[GrantB]

Woulden't a centrifugal clutch with the output locked solid act as a centrifugal brake?

If i use an electric fuel pump and a PWM signal won't that be a pretty good fail safe?

My head will be inches away from the plane of rotation so i better add in a scatter shield to be safe.

[Richard OConnell]

maybe. what kind of clutch exactly and how will it react to those kinds of rpms? Hope you wont be considering adding a clutch after a gear reduction :/

I think a pump cutoff would be an excellent backup plan, but i really dont like trusting sensors to deal with variables that can change on such short notice.

[GrantB]

I haven't seen a suitable clutch besides the HD auto clutch. And most in that torque range engage are a relatively low rpm.

The pump will be controlled via pulse width modulation. If anything fails it will most likely just turn off although a manual shut off valve is probably a good idea but more so for other reasons.

How about running 2 solenoids in a line controlled by to 2 simple rpm based micro controllers getting their signal from 2 different sensors? Would this react fast enough?

I have a friend from Rolls Royce that pointed out my idea of a snorkel pulling air from above the kart can be somewhat easily modified to separate larger particles. I figure anything can help and i can even have the scavenge re join with the exhaust to help mitigate and air flow restrictions caused by the shape.
www.triz-journal.com/archives/1999/02/a/index.htm

[racket]

Hi Grant

Have determined if the engine is a single shaft or a two shaft engine yet??

Does the output shaft turn if you turn the compressor wheel??

Or a different way of doing it which might be easier , if you spin the turbine wheel does both the comp and output shaft spin ??

If it does then its a single shaft .

If when you spin the turbine wheel only the output shaft spins and the comp remains stationary then its a 2 shaft engine with completely different torque characteristics and completely different gearing requirements .

A single shaft engine will only have ~10% of its power and ~20% of its max torque at 50% of its rpm range .

A 2 shaft engine will have 200% of its 100% rpm torque at nil rpm ( yep , twice the torque) and will have 20% of its power at 10% of its rpm , by 50% rpm it'll have ~75-80% of max power .

They are completely different animals, and if you want to have success with your build then you'll need to have the correct "gearing" .

Another thing you might need to consider is the engine itself , I wouldn't count on it having 80 hp if it was from a 10Kw genset , to achieve the low power output with half decent fuel burn rates the NGV is rather restrictive , they did the same thing with the Solar T62 engines .

With unknows like these its imperative to have the correct data before construction otherwise you'll be doing a lot of retrofit work .

Cheers
John

[GrantB]

It's a single shaft engine. Might be worth the price to sell this one and find a comprable twin shaft engine that I could run as a direct drive. Anyone know of a small sub 100hp free power turbine?

[racket]

Hi Grant

Theres the JFS 2 shaft engine , but they have their limitations and "peculiarities" to contend with.

Your single shaft engine isn't impossible to use , it just needs the correct setup .

Cheers
John