Interesting article on prototype tractors over the years. What I find puzzling is this description of one tractor engine
I don’t know a heck of a lot about turbines, but AFAIK the only turbine which has ever had that kind of horsepower to weight ratio is the one designed by Tesla. The other reason I find it interesting is that Tucker was working on a similar design for his cars when he got shut down. (Convential turbine, however, not a Tesla version.)
I’m not sure what your specific question is, but that power/weight ratio is nothing compared to some modern aircraft turboshaft engines.
See, I’ve always read that turbines don’t scale down very well, and that once you get below a certain size, they’re worthless. IIRC, the turbine Chrysler used in their car back in the Sixties, didn’t have as good a horsepower ratio as that tractor linked in the article. So I’m wondering what they might have done to get better power out of it.
What does hp/weight ratio matter for a tractor anyways? These things are supposed to be heavy, to the point of filling the tires with fluid and hanging ballast on the rims or off the front of the frame. What matters for a tractor is durability under load and fuel efficiency.
Not for a simple lawn mower, which is what that appears to be.
An 80hp lawnmower? :dubious:
There are some tiny tiny turbine engines out there. It’s not that they are worthless, it’s just that as you get into smaller applications there’s usually something else better suited for the job. And cheaper. Much cheaper.
Just judging from the external view of that engine (and that ain’t much), it would appear to be fairly standard with a single entry centrifugal compressor combined with a radial inflow turbine on the same disk, just like a lot of the other small Solar turbines floating around. It looks a lot like the “modern” T-62, instead of an older T-41 style engine which wouldn’t have as good of a power/weight ratio. It’s very close to what you would get if you built a turbine engine using an automotive turbocharger. The power/weight ratio listed on that page is not out of line with engines of similar design.
Not to mention the Shuttle high-pressure fuel turbine, which has a power-to-weight ratio of about 100 hp/lb.
The two turbines are different machines!
The “Strange Turbine” is powered by a liquid fuel of some kind. It is similar to an aircraft turbine that takes in air to burn fuel to drive the exit blades producing power.
The Tesla Turbine consists of a number of flat rotating discs, closely spaced between fixed or stationary disc. It is driven by a flow of steam. The output shaft can be connected to a generator or pump.
Tesla’s turbine can be driven by things other than steam. Tesla himself said that his turbine would perform better if it was driven by combustion gases instead of steam.
Adding all the parts necessary to make it a standalone turboshaft engine would drive the weight way up. The power/weight ratio would not be so remarkable then.
Que? Everything I’ve seen on the turbines shows that the gas powered version require less material than a steam version. I can’t find a good pic of one of the web, but if you look here you can get some idea of what a gas powered one would look like.
That sounds correct, but that wasn’t what I was trying to say.
You have to be careful to not confuse a “turbine” with a “turbine engine”. A turbine engine contains a turbine, and sometimes the whole engine is called a turbine. Just like how you might call your car engine a piston engine; it contains pistons, but it is not a piston itself.
The turbine engine in your tractor is a complete turbine engine. Not only does it contain a turbine, it also has all the parts to generate the gas that drives the turbine such as an inlet, compressor, diffuser, combustor, fuel system, etc.
The Tesla turbine is just the turbine itself. It’s a device that converts the kinetic energy of a fluid into mechanical power.
So, comparing the two in terms of power/weight isn’t really valid unless you figure in the weight of all the parts used to create the fluid energy for the Tesla turbine. Like I said, once you add all that in (either gas or steam), the power/weight ratio will come down. The part that sucks is that even when you add all that stuff on and make it a complete engine, some jerk like me (and a lot of other people) will come along and call the whole mess a “turbine”.
Ah, that makes sense. The problem with the Tesla trubine is that there haven’t been any serious studies of them, since Tesla was piddling around with them, and back then he was hampered by inadequate materials (one of the turbines was made out of nickel, which promptly stretched out of useful shape when it was used), and in the years since, all you’ve had are folks who’ve either made them totally wrong, or just dismissed them out of hand.