h a l f b a k e r yIncidentally, why isn't "spacecraft" another word for "interior design"?
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A turboprop engine is simply a gas turbine which is connected to the propellor shaft of an aircraft. As the engine runs, rather than using the turbine's natural thrust to power the aircraft, the propellor is turned at high velocities and efficiencies.
Simple: Find a small turboprop engine, similar
to that used in the Embrauer EMB-120. Heavily modify a minivan (most other cars would be too unstable and/or small to take a turbine like this) by lowering the center of gravity, increasing tyre width, and setting the driver's seat roughly in the middle of the car.
Replace the entire front end with the turboprop; the transmission runs straight through the center from the back; the car is rear-wheel drive. The fuel tank (full of JP-4) is in the rear.
Now you have a 3,000 horsepower car, without having to have a V-20 engine or half a dozen turbochargers. And no annoying rocket flames, as with the rocket trucks you see now and then.
Bonus: It makes a great noise like the Batmobile when you turn it on.
EMBRAER EMB-120
http://www.aerospac...ojects/embraer_120/
Manufacturer's webpage - engine model and specs [FloridaManatee, Oct 05 2004, last modified Oct 17 2004]
Pratt & Whitney PW100 series
http://www.pwc.ca/e...3_0_1/3_0_1_3_1.asp
Turboprop manufacturer's model specs [FloridaManatee, Oct 05 2004, last modified Oct 17 2004]
How Stuff Works - G/Ts
http://travel.howst...ks.com/turbine2.htm
Use of G/Ts in the M1A1 [FloridaManatee, Oct 05 2004, last modified Oct 17 2004]
Global Security - AGT1500
http://www.globalse...ground/m1-specs.htm
AGT1500 detailed specifications [FloridaManatee, Oct 05 2004, last modified Oct 17 2004]
Armour Reference Series - M1A1 Abrams Engine Compartment
http://ipmslondon.t...earticles/id16.html
Lots of pics and info [FloridaManatee, Oct 05 2004, last modified Oct 17 2004]
Global Security - M1A1 Ops & Support
http://www.globalse...ms/ground/m1-os.htm
Details of the PROSE Program and engine replacement [FloridaManatee, Oct 05 2004, last modified Oct 17 2004]
G2Mil Warfare Research Portal
http://www.g2mil.com/abramsdiesel.htm
Excellent articls on why the M1A3 Abrams should be diesel powered [FloridaManatee, Oct 05 2004, last modified Oct 17 2004]
Chrysler Turbine Car
http://www.museumof...ort.org/roads-4.htm
22 Mar 02 | Been there. Done that. [bristolz, Oct 05 2004, last modified Oct 17 2004]
Chrysler Turbine Car II
http://www.geocitie...age/7870/mopar1.htm
[bristolz, Oct 05 2004, last modified Oct 17 2004]
Rover turbine cars
http://www.ecars.co...er/GasTurbines.html
Not a new idea. [8th of 7, Oct 05 2004, last modified Oct 17 2004]
A turbine pleasure boat
http://www.turbineboat.com/
The emphasis on "pleasure," I'd imagine, is mostly for the boys. [bristolz, Oct 05 2004, last modified Oct 17 2004]
68 Tyrbine Indy Contender
http://www.ultimate...car.php&carnum=2036
Pratt and Whitney in F1/Indy [Giblet, Jul 13 2005]
[link]
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According to Embraer the manufacturer of the EMB-120, "The turboprop engines, Pratt & Whitney PW118 or 118A, each provide 1,800 standard horsepower" (link) |
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Pratt & Whitney Canada concurr with the rating, but these engines are optimised for aircraft use only. Therefore: |
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(1) They are designed with light weight, long TBO and fuel economy in mind, at the expense of all other considerations, including to a large extent, initial cost (compared to a reciprocating engine) |
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(2) Ther are designed for gradual increases and decreases in thrust, not urban driving. You'll void your warranty big time. |
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(3) They are designed to produce high power output, not necessarily high torque, especially from low revs. You'll probably have trouble pulling away from the lights. |
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(4) They are designed to produce thrust, not drive gears. You'll have to find some pretty specialised reduction gears. |
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(5) They are optimised for high altitude flying. Obviously, they'll still work at sea level, or the EMB 120 would never take off, but your fuel economy 'll be awful. |
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All that is nit-picking. Although it puts out 300BHP less than the PW118, the M1A1 Abrams tank uses the AGT-1500 gas turbine to great effect. Assuming you use such an engine, your only remaining problems will be: |
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(1) Weight. The AGT-1500 weighs in at 8,500 lbs, so you're going to need a more than special shocks fitted to your minivan chassis. It'll have to build like a ... a tank. |
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(2) Cost. One gazzillion dollars (I suspect this'll be the killer) |
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(3) Heat. The AGT-1500 exhaust measures 1,000F and that means troops cannot ride on, or walk near the M1A1. |
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(4) Fuel. Jet Fuel is hard to come by outside airports and you'll not be getting far on 0.6 miles per gallon. |
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BUT, all is not lost... the army, resourceful as they are, are strongly considering new engines for their M1A3 upgrade program, such as: |
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(1) Perkins CV12 engine rated at 1500bhp as selected for the US Army's Crusader field artillery system |
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(2) Detroit Diesel 1500bhp which powers Israeli Merkava tanks |
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(3) Lower rated engines such as the 1050bph engine now used by the Army's M88A2 tank retrievers |
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The upgrade program is expected to "improve reliability by 30%. Some of these engines could achieve a 4-5 fold improvement in reliability, a 35% reduction in fuel consumption, a 42% reduction in the number of parts, and a 15-20% improvement in vehicle mobility. Life cycle engine O&S costs are projected to drop from 16 billion dollars over 30 years with the current engine to 3 billion dollars with the new engine." |
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Buy yourself a diesel minivan, Mac. |
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PS - nice fantasy, though (+) |
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[Rods], a turboprop is a G/T with a bigass prop on the front. Why in the heck do y'all want to put a air prop on a minivan or boat? |
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Ohhh, I see you live in the Everglades. OK, now imagine an airboat with an 8,500lb engine on top. Imagine yourself strapped into your seat, watching the silouette of a gator swimming at the surface twelve feet above. |
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Yes, there are turbine boats. There are a couple of offshore racer types occasionally seen on the waters near where I live with turbines in them and, of course, then there's the unlimited hydroplanes which are nearly all powered by turbines these days. |
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8,500lbs? I think a 420shp Allison weighs about 160lbs, they're pretty little. |
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Rover built a technology demonstrator gas-turbine car in the middle of the last century. It's in the Science Museum in London. It worked OK; its one real limitation was a total absence of acceleration. I think the powerplant was a Garret AirResearch Unit. |
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OK, so it's not practical, you'd run outta fuel real quick, you'd void your warranty, you'd have to modify your car (lots)... |
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There is one of the Rover Engines (gas Turbines) in a lab at Coventry University, from what i remember of the testing we did with it and lectures about it the problem is gas turbines have a fixed ioptimal performance band, anywhere outside of it and performance fuel economy etc fall right off. |
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use this engine
www.starrotor.com/Engine.htm |
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I think I've seen lots of turbine -related stuff on here before, but I'll add my penny's worth. |
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Always fancied the idea of anything turbine-powered to be honest because they make such a great noise... especially at high power levels (screeeeeeeeeeeeeeaaaaam) and when powering up/shutting down. |
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Anyway, I reckon the way to do it would be a micro-turbine (example: search for Capstone turbines) generating power used by a beefy electric motor at each wheel, so you get controllable AWD and regenerative braking to boot! The biggest problem may be heat cycling: if you power a turbine up and down it's EGT (exhaust gas temp) fluctuates and can end up cracking blades, exhaust ducting etc. Use batteries or fuel cells to provide the acceleration. |
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Not as much fun to look at as a camper van with a BFO plane engine on it though... |
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One of those links may discuss this--the right way to drive a turbine car is with the RPMs up and the clutch slipping. Nobody did that, so they got a bad rep for being sluggish. Do it right, and the fuel and clutch burn up fast, but so do the tires. |
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A turboprop engine doesn't produce much thrust. It produces torque at an output shaft, typically to drive a prop. They've got a great power-to-weight ratio and good efficiency when used at the proper conditions. These conditions usually involve long periods at a constant power setting. |
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Turbines don't naturally run better at a high or low altitude. That's simply a function of the design. If you're going to fly high, design your engine to run well there. |
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Turbine engines don't necessarily have low torque, either. That's just a function of the torque turbine arrangement. With the use of variable turbine nozzle blades, torque curves can be modified on the fly. |
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The "long periods at constant power" is the killer when it comes to automotive applications. Turbines run at very high temperatures. Constant throttling produces very destructive thermal stress on the material. Turbines are also not very efficient when they're running off-design. |
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There are "hybrid" trucks that use a turbine to run a generator, which charges batteries, which run an electric drive train. These are very efficient. A turbine in a similar automotive application may just work, if an efficient turbine can be made compact and cheap enough. |
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Now that I've said all that, a soccer-mom minivan powered by an 1800-hp turbine would certainly be fun, if nothing else. |
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I'm imagining that Mom wouldn't quite know what to do about a hot start, though. |
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