Good Turbine For Car.

[aquaticharpy]

Would a CVT be more efficient?

Or some transmission that is similar to cvt, where you can pick a speed, but the turbine is always at 100% except for idle and startup?

What do you think?

Thanks
John

[aquaticharpy]

Just found this odd sketch on a manual cvt design blog post. What do you guys think? The efficiency of always having 100% turbine speed with the drivability of a regular car~ sort of.


How do you think this would/could work?

Thanks 
John 

[stoffe64]

Eeehhh?I dont Think it was meant that way.

[aquaticharpy]

And turbines weren't meant for land vehicles. But somehow people got ideas and look where we are now. That's a very simple version of something that could work.

Turbine engines, as we know, are most efficient and like being at full throttle all the time, yet, in a car your engine does a lot of low speed.

So instead of having the engine do the work, we have the transmission change the speed going to the tires.

That, and a big ol' disc break flywheel on the output shaft to grab onto for gear shifting I'm thinking might be decently efficient..

Ideas?

Thanks
~Johm

[aquaticharpy]

The torque of the turbine would come in handy when you do want to try and get fast acceleration as you approach stall speed you'd get torque, thus helping to get you going..

[racket]

Hi John

A CVT transmission could be used with a single shaft engine ...........as I mentioned in an earlier email reply to you .

With an engine running at 100% it'd be similar to a Garrett TPE331 aero engine which is a single shaft turboprop , the variable prop ( CVT trans) does the "power changes" allowing going from idle power setting to full thrust power very quickly without the need to accelerate the rotor , just increase the prop pitch in conjunction with the fuel control supplying more fuel.

Cheers
John

[aquaticharpy]

So you're saying a single shaft engine would be better now..

A CVT would allow a 2 shaft to have work well I'd think with reverse. Just a speed sensor and a big ol disc break for overspeed protection and finding reverse or forwards. And a CVT manual transmission that goes down super low so we can have low or high speed cruising...

Still lost ~John

[aquaticharpy]

Also you havent said a word about CVT before to me in any form... :/

[racket]

Hi John

My comment of 7 October .......The other alternative is a small single shaft APU and mate it to one of those infinately variable transmissions to hopefully provide a reasonable power supply .

A CVT is such a transmission ............Google it !!

I stand by my assessment that you should NOT attempt this build.

Cheers
John

[aquaticharpy]

My apologies.

I guess unless I figure something out~

This dream is dead.

Goodnight
-John

[racket]

John

We've given you all the alternatives available , there are a very limited number/variety of engines out there , hence very few turbine powered vehicles , the option in my last post has more chance of success due to the greater number/type of single shaft engines for sale and the relative easy availability of CVT transmissions in the smaller horsepower range.

You can either take my advice which is given in good faith , or do your own thing and be responsible for the outcome .

Cheers
John

[aquaticharpy]

I have one question:

Would having a free power section like on a Boeing turbine have any advantages over single shaft when linked to a cvt.

Thanks
John

[miuge]

It all seems so simple when you outline it on paper or play with an idea in your mind, but when it's all supposed to realise things will change. As for the first turbine project I'd personally recommend to keep it as simple as you can, forget the transmissions and make it just direct drive from the freepower section. If you need a "neutral gear" add a wastegate between the stages, reverse gear can be done with an electric starter motor on the rear axle like they do on chain drive motorbike engine swaps.

If the transmission is a must for some reason, for me an automatic like a two-speed PG would seem simple. High and low speed, and a reverse in one, quite compact thing with a great variety of options. High stall lockup turbine to keep freepower spinning.

Single shaft with a CVT; Where to find one and how to control it, ATV or a snowmobile?

[aquaticharpy]

I think I'm going to get a Rolls Royce Gem.

Thank you miuge for the words of encouragement~

A wastegate might be hard to implement but I think it's been done before as I replied in a previous post where it was done in the Howett Race Car...

Either that, a torque converter, or a big ol disc break like I've been ranting about..

I'll do some research 


Thank you!!!
~John

[aquaticharpy]

This was also a bit of an interesting read

turbinecar.com/wiggins.htm

Edit: I've found what I think is a solution from a Wikipedia article

"The free-turbine engine was particularly favoured. It did not require a clutch, as the gas generator could be spun up to operating speed without requiring the output shaft to rotate. For the Wessex this was used to give a particularly fast take-off from a cold start. By locking the main rotor (and the power turbine) with the rotor brake, the engine could be spun up to operating speed, then lit, and when the engine core is at the operating speed of 10,500 rpm the brake is released and drive to the rotor smoothly increased as the power turbine gains speed. This was used to bring the rotor to speed from stationary in just 15 seconds and a time from engine start to take-off of only 30 seconds.[2]"

With the Rolls Royce Gem engine I think this would be a valid option for race and drag.

But being a simple direct drive we have the fuel problem again with having the turbine at idle with low speeds..

Could the main rotor be restricted to restrict speed?

This dilemma of fuel efficiency led me to cvts... 


-John