F1technical.net

flynfrog wrote:Ill add in the Boeing kenworth

The video is not telling you that the turbine powered truck probably used 50-100% more fuel. Those were at least the data I found in a comparison of the turbine powered Abrams tank versus the turbodiesel powered Leopard2.

AFAIK this lack of energy efficiency is not curable for turbines that are used in land vehicles. So they will always be an exotic experiment for high performance cars but not useful for standard ground transportation.

WhiteBlue wrote:
The video is not telling you that the turbine powered truck probably used 50-100% more fuel. Those were at least the data I found in a comparison of the turbine powered Abrams tank versus the turbodiesel powered Leopard2.

I think everyone in this thread knows that a turbine built in the 50s and probably designed in the 40s gets terrible efficiencies. One of the main selling points of those trucks was that they could burn any fuel. Fuel was cheap back then.

AFAIK this lack of energy efficiency is not curable for turbines that are used in land vehicles. So they will always be an exotic experiment for high performance cars but not useful for standard ground transportation.

So all development should cease because you said so? Cars should only have L4 Diesel cycles?


As pointed out earlier couping a very small turbine to an electric drivetrain would allow you to keep the turbine in its most efficient area. There is also recovery stages that could be added. Is it going to make it in the real world who knows but its cool to see something different now and then it makes more sense than a plug in car right now.

flynfrog wrote:As pointed out earlier couping a very small turbine to an electric drivetrain would allow you to keep the turbine in its most efficient area. There is also recovery stages that could be added. Is it going to make it in the real world who knows but its cool to see something different now and then it makes more sense than a plug in car right now.

very small turbines are inherently inefficient due to the high leakage around the blade tips ?
(though small diameter has a disproportionate benefit to structural weight ?)
and active control of tip clearance seems unlikely in a car 'range extender' application

autogyro wrote:There is something most people do not realise and that is the two thirds of total fuel used climbing to altitude.

Again almost complete rubbish.
A 747 burns about 10 tonnes to get into the cruise and with the average leg being 7 hours or so and the fuel burn on that leg being between 70 - 80 tonnes, the climb burn is maybe 15% at worst.

I remember the Chrysler turbine car very well. It overheated and broke down in front of our house in south Phoenix and it being before cell phones were a dream they had to borrow our phone to have the crew come and pick them up.

Tommy Cookers wrote:

flynfrog wrote:As pointed out earlier couping a very small turbine to an electric drivetrain would allow you to keep the turbine in its most efficient area. There is also recovery stages that could be added. Is it going to make it in the real world who knows but its cool to see something different now and then it makes more sense than a plug in car right now.

very small turbines are inherently inefficient due to the high leakage around the blade tips ?
(though small diameter has a disproportionate benefit to structural weight ?)
and active control of tip clearance seems unlikely in a car 'range extender' application

Blade clearance is part of the tolerance issue I posted in an earlier post. We build some engines with a flame spray ablative seal on the stators so that when the turbine went though its break-in cycle it would in effect clearance the stator to the tips to minimize the gap.

piast9 wrote:Nice thread. I didn't realize that the turboshaft engines in the cars were actually running apart from few prototypes of trucks and racing cars. The sound of the Howmet TX at the Spa is amazing and the turbine changes rpms faster than I was expected.

The Howmet TX used a freeshaft engine equipped with power turbine bypass valves. In a freeshaft engine the gas generator shaft is independent from the power turbine, a design used in most helicopter type engines. Since a turboshaft engine have a rather poor throttle response, it was equipped with the power turbine bypass valves. When the driver release the throttles the bypass valves opens allowing the gas generator to keep running at high speed, while torque output from the power turbine drops. When the driver goes back on the throttles the bypass valves are closed, increasing the torque from the power turbine.

Since the Howmet TX only had a single speed reduction gear, power turbine speed increase with car speed.

flynfrog wrote:As pointed out earlier couping a very small turbine to an electric drivetrain would allow you to keep the turbine in its most efficient area. There is also recovery stages that could be added. Is it going to make it in the real world who knows but its cool to see something different now and then it makes more sense than a plug in car right now.

This type of drivetrain was tested by Volvo in the nineties, and they actually made three prototypes; a car and later a bus and a truck. The car used a 50 kW turbine engine designated VT 40 and truck and bus used a slightly more powerful version designated VT 100. The turbine engine used a single stage radial compressor and a single stage radial turbine, a directly driven high speed permanent magnet alternator and a recuperator to reuse waste heat. The conversion efficiency to electricity was about 25-30% and it was used as a part of a series hybrid drive.

Small turbine engines are due to their size not very efficient. To keep production costs reasonable there is also less room for expensive heat resistant materials and complicated designs like turbine blades with internal cooling, which also hurt efficiency.

Just ran across this a powdered coal fired Eldorado.

The General plays with fans.

Whole article here
http://www.thetruthaboutcars.com/2010/1 ... r-program/




I would hate to think what happened when that powdered coal tank got ruptured in a crash.


They apparently had an EV1 with a APU

As the Chevy Volt is just now coming to market, it’s interesting to note the performance specs for the EV1 Series Hybrid concept of 1998:

“The driver simply flips a switch that disables the APU so this experimental car can be driven in the zero-emissions mode for up to 40 miles. The 6.5-gallon fuel capacity provides more than 350 miles of continuous highway range, better than most cars on the road today.”

Macs Garage had a cool video of the Big Red

http://www.macsmotorcitygarage.com/2016 ... more-49487

Bonus picture of the kenworth turbine

I have never seen the Plymouth turbine before either.

Jay Leno's Chrysler turbine car (similar or same car as the first post) was on the James May's Cars of the People programme at the weekend. The programme will be on iPlayer if you missed it, or possibly other ways of seeing it online

The comments regarding aircraft turbine engines are inefficient at cruise have little ground.

At altitude, as the air density drops, the maximum thrust of the engines also drop, so they actually operate at %85-90 N1 at cruise. When an aircraft has an engine failure at altitude, the first thing it does is to DESCEND, as it simply does not have enough power to stay in the air when that high. So yes, jet engines are most efficient at full thrust, and they operate pretty close to that at cruise.

Twin engine fighter jets typically shut down one engine when loitering, as they have enough power to sustain a high (>30000 feet) altitude with one engine operating at military power.
[/offtopic]

I think turbine engines will have some use for ground vehicles sooner or later, because by design, they have the potential of operating at a higher efficiency than reciprocating engines. Theoretical maximum for diesel engines is ~%55 and ~%65 for turbine engines, the key differentiator being the compression ratio. It is currently impossible to efficiently scale down turbine engines currently, but I believe that hurdle will soon be overcome.

Lastly, there is one ground vehicle application of a turbine engine that I'd like to mention:



68 tons, 1500 hp, top speed ~85 kph (although governed to 75 kph). Rather thirsty though...

Jay's garage. 24 minute episode on the Chrysler turbine.


Book source from Steve Lehto, an attorney and Jalopnik contributor.
http://www.amazon.com/Chryslers-Turbine ... 4680656713

livinglikethathuh wrote:The comments regarding aircraft turbine engines are inefficient at cruise have little ground.

At altitude, as the air density drops, the maximum thrust of the engines also drop, so they actually operate at %85-90 N1 at cruise. When an aircraft has an engine failure at altitude, the first thing it does is to DESCEND, as it simply does not have enough power to stay in the air when that high. So yes, jet engines are most efficient at full thrust, and they operate pretty close to that at cruise.

Twin engine fighter jets typically shut down one engine when loitering, as they have enough power to sustain a high (>30000 feet) altitude with one engine operating at military power.
[/offtopic]

I think turbine engines will have some use for ground vehicles sooner or later, because by design, they have the potential of operating at a higher efficiency than reciprocating engines. Theoretical maximum for diesel engines is ~%55 and ~%65 for turbine engines, the key differentiator being the compression ratio. It is currently impossible to efficiently scale down turbine engines currently, but I believe that hurdle will soon be overcome.

Lastly, there is one ground vehicle application of a turbine engine that I'd like to mention:

http://images.tapatalk-cdn.com/16/02/11 ... 5530b2.jpg

68 tons, 1500 hp, top speed ~85 kph (although governed to 75 kph). Rather thirsty though...

Yeah, for sure - that "rather thirsty" Chrysler gas-turbine M1 tank serves as fairly signal evidence of the inherent limitations..

Here is a NASA proposal that shows the potential for a high efficiency 2T diesel ICE helicopter mill to better the gas-turbine..

http://www.ntrs.nasa.gov/archive/nasa/c ... 001160.pdf

That car was on James May's Cars of the People last week btw