Truck engines: Diesel vs. Turbine

Hello all, I was curious, what does everybody think would be a better engine for a medium-duty truck, A diesel or a turbine? The turbine can use anything flammable for fuel and can't be stalled!

 

The turbine would also not meet emissions or fuel economy standards any more. Automotive gas turbines were "the next big thing" in the fifties and early sixties and none saw successful production. Ford did build about a hundred of the Model 707 or 710 engine and bought them all back and destroyed them because of hot starts, hung starts and so forth.

Early gas turbines were pretty omnivorous but as turbine temps have gone up they were increasingly fussy.

There were some good books written at the time you can still find. The cost of turbine engines was very high also, although modern CNC soft tooling has made fabrication a little cheaper. The final nail in the coffin was emissions.

 

Use a turbine to heat the water. Waaaaay easier than wood to start in the morning

 

Perhaps not for a new truck, but retrofitting into an old one would not be an issue.

 

look up the cost to run and maintain a turbine powered small aircraft, and you will get an idea what you are getting into, turbines of any sort are not cheap or easy to keep up, they also require you know what you are doing when you operate them, someone was running one in the hot rod power tour a few years ago, later model truck with an allison under the hood, he said everyone thought it was just a sound effect until he opened the hood, if you have deep pockets, you cant beat the cool factor though

 

The "official" HAMB answer: FLATHEAD.

 

Ha ha - At least that fits what the HAMB is all about ~ and it sure as hell isn't Turbines or Diesel's in an old Dodge pickup

 

There were experiments in the 50's and 60's, but none ever went to full production.

American LaFrance made 4 firetrucks with turbines. Note the stack behind the cab.

 

people have been playing around with turbine powered cars for a long time, it's actually traditional, even Harley Earl had a few concepts powered by them

 

not traditional? http://en.wikipedia.org/wiki/General_Motors_Firebird

 

we run a small turbine at work in the power plant , its shaft spins a 2 megawatt generator , and the exhaust heats a 2 stage steam boiler to 200 psi the engine is about the size of a small back yard cement mixer drum , the exhaust temperature is 1300 degrees and wide open or cut back it burns 4 gallons of #2 diesel a minute , the bearings need oil coolers and its more than id want to have to work on , go with a nice diesel engine with a turbo a lot less headaches and less likely to have a dangerous hi rpm failure with hot shrapnel flying about

 

I worked at Garrett aerospace back in the 70's and they installed one of there industrial turbines in a white semi truck. They used to drive it loaded from Phx. To flagstaff to gather data points. That thing kicked everybody's ass, the only way you could tell it was a turbine was it had two hood scoops and twin square exhaust stacks. Remember turbines have to run at a constant speed (around 100k rpm's) but everything else has to run at normal rpm's.

 

Just because something was done once does NOT make it fit the HAMB. I have always been under the impression that this place is about Hot Rods and Customs done in a style of the early days by regular guys. Not some one off experimental thing that was done by a factory to show it's engineering prowess, even they acknowledged these were just design exercises. That doesn't make it "traditional"

 

How about a highboy 32 Ford roadster with gas turbine power - in 1962?

http://www.lennybabe.net/roadster/Turbine.htm

Some history:

He bought the car from Preston Tucker's son in Ypsilanti Michigan in 1949 or 50 and built it as a fenderless roadster with a 41 Ford flathead, suitably hopped up. Changed the flathead for a 303 Olds V8 as soon as they became available. Ran 134.12 at Bonneville in 1954. Traditional enough so far?

As a Boeing employee he heard of a used gas turbine engine going cheap and decided to put it in his hot rod. This would have been in 1960 or 61, the car was back on the road in its 4th version in 1962, and is basically the same today.

 

Turbines make sense for steady state operation and steady load operation neither of which works well in a truck.

There is some work being done on variable power turbines now primarily to power a generator for a turbine-electric drive.

 

Traditional? Hall-Scott...

 

The purpose designed automotive turbine engines had regenerators, and variable guide vanes or a PT-to-CT lockup to provide engine braking. They were thus able to operate more efficiently over a wider range than an aeroderivative engine would have been, but they were never highly economical. Idle and part throttle fuel consumption were definitely high.

But no one cared then.

 

This car was written up in the Carroll Smith book on "Automotive Gas Turbines". I must have checked that book out of the library fifty times as a kid.

 

Most of these swaps involve surplus or runout aircraft engines no one wants and are not terribly expensive. People get swindled into paying a lot of money for these things because they assume that engine has to be worth a lot of money. An aircraft engine that is no longer wanted for flight use because no one operates the type anymore, or that engine is a turkey and is run out or otherwise not cost effective to overhaul or hot section is worth scrap....and that really is not very much. High energy metals are expensive as raw materials but they are not precious metals as is gold or platinum. Scrap titanium is worth less than a dollar a pound, Inconel or Waspaloy or Rene 41 a little more or less. A PT-6 engine that is $600K new would be worth about two hundred bucks if you ran it through an SSI Shredder.

Of course more popular engine types may have parts with core value, but those are parted out as soon as they come off the airplane.

Early dash number 331 Garretts, for example, are perfectly rebuildable but no one does because later dash numbers are readily available with time on them for less than a hot section. This is a single shaft engine not suited to car use but the principle is the same.

Most people don't know that the Granatelli STP Indy turbine cars all had junk, unairworthy PT-6s Granatelli more or less conned P&W into giving him. P&W later regretted it because when the car DNFed they felt it reflected badly on them.

 

I guess you would use a turbine with a reduction and then a high-stall speed converter, so you get the most constant RPM while accelerating.

It goes without saying that a 6BT out of a late dodge truck can't be beat in terms of usability & cost. But it also goes without saying that if those were your only motives - you would just buy a late dodge truck.

So, having said all this stuff that goes without saying - go for the turbine !

 

What kind of transmission did they use? A bunch of gear reduction and then some type of regular automotive transmission?

 

You don't need a torque converter, the power turbine acts as one already.

I am not sure exactly what the PT6 Indy cars used. I know they were all four wheel drive and on the 1967 car the transfer case was cracked because the designer was an idiot and refused to put a U-joint or CV joint on it. There were no gears to shift, it was an output to the transfer case and driveshafts to conventional front and rear IRS diffs. I think they were Halibrand quick change but not sure.

Different PT6 or ST6 engine dash numbers have very different power takeoff styles, either a high speed (~15-18K rpm IIRC) output or a geared down drive for a helo transmission or a propeller drive. The propeller drives are probably about 2000 rpm give or take. A google search should prove useful.

On the Chrysler automotive engines, the PT turned a high ratio set of gears and drove the front of a 727 TorqueFlite transmission, which was built into the engine permanently. The transmission fluid was the engine oil and they tapped it off to run the power steering as well. I believe the brakes were power assisted by bleed air. The Chrysler engine's power and gasifier sections were much smaller than a PT-6, the compressor wheel was about the size of a modern tractor trailer turbo's. Therefore they turned a lot faster, 40K rpm was roughly the range as I recall. There was a big external lever like the kickdown lever on an old Ford that worked the movable vanes. I saw one run at a Mopar meet in the nineties. It sounded like a Kirby vacuum cleaner and EGT at idle was such you could, and I did put my feet under the exhaust outlets for a nice warming. The caretaker jazzed the throttle and I moved back pretty quick as it got quite hot-not enough to melt asphalt though.

 

I would add that on later versions of the Chrysler they did use a torque converter after the gear reduction and put a pulley on it with a belt to turn the A/C compressor. Fuel economy went from bad to worse. The first through fourth versions had no good way to turn conventional accessories because taking any power off the CT section and accessory section caused terrible lag and unloading overspeed issues. The last gen engine that might have seen production in 1981 or so, had a tertiary PT for accessory drive that finally solved the issue. I think there were eight separate Marks or versions of the engine over a 25 year period, only one was produced in more than three or four piece quantity.