kb58
Dork
10/4/14 12:23 a.m.
You know the turbine-powered cop cars in the movie "THX1138?" While awesome, they were obviously fake. And then, good lord, I see that such a thing really exists... Combining the early IMSA look with a turbine is truly an "11" in my book.
http://www.ascottcollection.com/#!howmet-tx-gb/c1uzv
Play the video with the sound turned up!
https://www.youtube.com/watch?feature=player_embedded&v=x24c-7pJZeM
In French, but has an awesome startup (jump to 1:40)
https://www.youtube.com/watch?v=JV4mYoEeGjY
Was expecting Singer 911. This is far and away much better!
Wasn't there a crapcan racing team who got their hands on a small (~300hp) helicopter turboshaft engine and were going to stick it in a fiero or something crazy like that?
Also reminds me of this guy, who solved his turbo lag issue, with a turbine https://www.youtube.com/watch?v=6EMleegZQLw
In reply to Kenny_McCormic: That is badass! Give me some earplugs, please.
You'll notice that it wasn't the fastest thing on the track by far. I saw a Porsche 917 (I think) go flying by it with ease.
How are turbine driven cars actually driven? Like, what's the coupling to the drive wheels? I would think the insane types of rpm that a turbine runs at would make it difficult to gear the primary shaft down to being a reasonable setup to get rotational power from.
JG Pasterjak wrote:
How are turbine driven cars actually driven? Like, what's the coupling to the drive wheels? I would think the insane types of rpm that a turbine runs at would make it difficult to gear the primary shaft down to being a reasonable setup to get rotational power from.
Dunno myself, but look at competition pulling tractors for the answer. They work very well.
I will say all turbine engines from aircraft have a pto so they can drive all the gee-gaws, from generators to pumps.
I actually saw the Howmet turbine car race once, at Donnybrook Speedway (Brainerd International Raceway today) back in 1968. The turbine sound was weird, compared to all the other cars on the track, but it was pretty fast.
That is incredible...
warning, slight thread detour... So why are turbines not used in racing?
Will
SuperDork
10/4/14 8:45 a.m.
In reply to JG Pasterjak:
Same way a turboprop drives the propeller?
There's an additional fan behind the turbine. It goes: Compressor fan, fuel injector, turbine to capture expanding combustion gases and drive compressor fan, fan to capture the exhaust gases and turn that into useable power for propellers, wheels, etc.
In reply to JG Pasterjak:
The Howmet TXs are driven by turboshaft (helicopter) engines. Wiki says the power made it to the wheels via reduction gearing off the shaft.
http://en.wikipedia.org/wiki/Howmet_TX#Turbine
I found more pictures here, including some slightly more detailed looks at the drivetrain:
http://www.avonaero.com/Howmet%20turbine.htm
And a little bit of how a turboshaft works:
http://helicopterflight.net/engine_fig_.htm
http://www.defencejobs.gov.au/navy/aviation/aircraft.aspx (scroll down for animation)
noddaz wrote:
That is incredible...
warning, slight thread detour... So why are turbines not used in racing?
They were at Indianapolis briefly, then banned:
http://www.autopuzzles.com/Indy1967.htm
Poor throttle response. Might work for Indy, probably a bad choice for a road course.
I saw this car in person a couple of years ago. Must have seen it on the track as well, but it didn't make as much of an impression as the 917s and the Columbo V12s.
jstein77 wrote:
You'll notice that it wasn't the fastest thing on the track by far. I saw a Porsche 917 (I think) go flying by it with ease.
The 917's were a later generation and made upwards of 1000hp. The Howmet was rated at 350hp and only had a single speed gearbox. When they raced against the 908 they were about a second per lap behind.
As to the throttle response, they used a Wastegate system to allow the turbine to react more quickly to driver input. A gearbox with more gears would certainly help acceleration out of the corners as that was what hampered them at Le Mans, they weren't fast enough on the straight which hurt their lap times. A multiple-speed gearbox was planned for 69, but Howmet pulled their sponsorship and the program died on the vine.
WSC 917s and Can-Am 917s were not the same, of course. The Le Mans cars made about half the power of the famous 917/30 in race trim, and more like a third in qualifying trim. Still, there was a step change in performance around that time and the Howmet wasn't in the same league.
RossD
PowerDork
10/4/14 10:07 p.m.
A jet engined car would be a good match for a CVT unit.
Turbines don't react well to throttle type action typical in cars. React slow to input and coast when the throttle is released. Too quickly and bad thing happen. They are better at running at a steady rpm. What would work would be some type of variable gearbox that output could be varied by throttle with a constant input.
I think the turbine powered tanks use the turbine engine to power a variable pump that controls output. I'm a turbine engine helicopter guy so not that sure about the turbine engine tank operations, just what I've been told. There are ships that also use similar setups. Turbines powering pumps that drive the system.
In reply to wlkelley3:
Turbo electric hybrid using a bigass capacitor bank? Hold speed on the straights with the 300HP or so the turbine makes, come out of the corner with a lot more than that built up from slowing down and trickle charging on the straight.
kb58
Dork
10/5/14 5:08 p.m.
Efficient, slow, or fast, I'm pretty sure it would have the biggest crowd around it at Cars and Coffee. The combination of the sound and shape is what does it for me.
This shows the basic principle of the Allison turboshaft engine. Replace the propeller with a rear differential and drive your car. This system can have significant lag.
There also are constant speed turboprops that spin at a very narrow rpm range. These respond to power changes by increasing or decreasing the propeller blade angle to maintain set rpm. These have fantastic throttle response, but would be harder to use in a car.
Opti
Reader
10/6/14 12:56 p.m.
About ten years ago I read Jay Leno has a bike with a helicopter turbine engine. Supposed to spin 85000 rpm, not 8500. Never heard anything else about it though
06HHR
Reader
10/6/14 1:04 p.m.
In reply to Opti: That would be this thing MTT Y2K It was in a movie about something or other called Torque too.. Neat piece of kit
So; Beefy CVT on 10:1 reduction drive w/AWD would make this terrifying?