Given all those advantages, it'd be pretty easy to design a 20 or even 30+ mpg RV without downsizing, or magic.... But I suppose most folks will put it down to some sort of conspiracy theory.
I'm not denying that railroads are an inherently efficient mode of bulk transportation. But they clearly demonstrate that large electric powered vehicles are eminently feasible. Rolling resistance is a relatively small power drain at the highway speeds we consider necessary. Freight railroads move along at a good clip too and while a long train of cars does gain efficiency from "drafting" the aerodynamics of trains are poor. Running the prime mover at the most efficient speed for the power needed is an advantage and ultimately who says it has to be an IC engine? Fuel cells are gradually becoming mainstream and might one day power an electric vehicle without the charging issues associated with batteries.
To top it all off the first generation View/Navion could turn in 16 mpg with a power train that was right off the shelf. The long haul trucking industry may devote a lot of effort to fuel economy but do light trucks, the underpinnings of class C RVs, get the same? I don't think so, I don't think anything is pushing Detroit to work the same magic for this market segment as they did for passenger cars. The government is giving them a free pass. Tellingly the View powertrain comes from Europe where there is some pressure to do better and the results show it. Even if you were to argue that the Europeans have pushed current technology to the limit I think most of us would be quite happy with 16 mpg.
I don't think we need to imagine a conspiracy here unless it is the conspiracy of mediocrity. GM looked at Diesel electric power in the 50s and proved that it was uneconomic? Back when Diesel fuel cost a fraction of the price of gasoline instead of 130%? What does that prove? It proves that 1950's technology was insufficient to the task when the price of fuel was almost negligible. We don't have those fuel prices or that technology any more.
This fall will mark the 400th anniversary of what is normally accepted as the invention of the telescope. The lenses needed to build a workable telescope had been available for over 300 years by then in the form of the eyeglass industry and isolated individuals during that time span have left writings describing the use of telescopes. Yet the telescope as a work-a-day tool remained unknown until 1608. Just because something is not commonly being done does not mean it is impossible. Here was a case where human industry remained locked into a single thinking pattern for hundreds of years even though the available technology was sufficient to enable new applications. If a 5 cylinder View could get 16 mpg with totally standard components then the only slightly larger MH that I want could probably get 20 mpg with some serious effort.
Everybody keeps touting the View/Navion gas mileage.
I've been in plenty of these at dealers and shows. They just plain do not have the room or convenience of my 10-11 mpg wide body American-van based small Class C ... so we would never buy a View/Navion type RV if there's any way around it gas-budget-wise or otherwise. They better get better gas mileage for what you give up to own one. Plus they cost way more new than what we paid new, so we can buy plenty of the extra gas we'll need, as and if we need to, instead of being locked into the high View/Navion sunken cost purchase price. We all know better gas mileage is possible with more cramping in our RVs ... Europe and Australia prove it and will continue to do so.
The challenge to the vehicle design engineers - and what I took the jist of this forum thread to be - is how can US and certain other RV'ers in the world not give up room-based-comfort while at the same time get better gas mileage to boot?
Even with modern IC engines, a lot of the energy in gasoline is still wasted. I'm no railroad engine designer, but it appears that their constant speed IC engine plus torque conversion electric motor is basically very similar, other than for battery energy manipulation and computerized control, to the approach Toyota uses in their Prius. It's time Detroit delivered more power to the ground for our precious gasoline dollar - in RV trucks and everywhere else.
I understand that a new crop of 2009 consumer grade diesel powered vehicles will finally begin to offer that here in the US. It's about time ... too bad it took fuel price to do it - the Earth could have used the relief a long time ago.
pnichols wrote: Everybody keeps touting the View/Navion gas mileage.
I've been in plenty of these at dealers and shows. They just plain do not have the room or convenience of my 10-11 mpg wide body American-van based small Class C ... so we would never buy a View/Navion type RV if there's any way around it gas-budget-wise or otherwise. They better get better gas mileage for what you give up to own one. Plus they cost way more new than what we paid new, so we can buy plenty of the extra gas we'll need, as and if we need to, instead of being locked into the high View/Navion sunken cost purchase price. We all know better gas mileage is possible with more cramping in our RVs ... Europe and Australia prove it and will continue to do so.
The View/Navion show what is possible to achieve by, in the main I think, accepting a smaller, Diesel engine. Yes, they also have a somewhat smaller frontal area but they are certainly not in any sense of the word aerodynamically efficient so perhaps a less powerful class C of traditional size with some aerodynamic enhancements could achieve the same fuel efficiency. That is why I mentioned the View. I understand that they are too small for some and too limited in CCC for many as they stand. But some of the naysayers will more readily accept that the View demonstrates an achievable goal than a big EMD locomotive.
I don't know why they are so expensive. I don't know why any of the Diesel MH options are so expensive for that matter. I drive a Diesel powered VW Passat and the list price was $300 more than the list price of the base turbocharged 4 cylinder gasoline engine in that model. Both were thousands of dollars less than the V6 gasoline engine upgrade but then the latter was bundled with a bunch of other options and the package price doesn't fairly reflect the price of the V6 by itself. Power and torque wise the VW Diesel I drive is the equal of the original I5 View engine. I suspect that it is the Mercedes-Benz nameplate (even though only implied in this case) that carries the price premium, not the little Diesel engine. Or maybe the chassis is not all that more expensive and the MH makers just choose to build premium priced products on them because their uniqueness in the market will support that.
You see them so often you tend to forget about them. Look at the tow rating on that thing! Railroads claim they will tow a ton 400 miles on a gallon of fuel. Your ten ton MH would need 10 gallons of fuel for that distance or 40 mpg. Of course part of that efficiency comes from the low friction of steel wheels on steel rails but surely not all of it.
Ken
Part of the propaganda regarding the high efficiency of the railroad is that it can haul such huge weights. Those engines are not efficient, or at least one wouldn't think that burning about 150-200 gallons of diesel per hour per engine was very efficient. In that hour, the train would go about 60-100 miles, depending on several variables, but at best, they are getting about 1/2 MPG. The "Spin" is that they can carry a huge amount of cargo, so they advertise as moving a ton 400 miles, when it's actually more like 800 tons, going 4oo miles on 800 gallons of fuel.....But who wants to read about that.
Of course, they could also say that they could put about 50 RVs on the train, and move them, which would be much cheaper than if we drove those 50 vehicles (at 8 mpg) the same distance....and that is their point!
I work on these (16-Cylinder, Supercharged, 1950 HP, EMD) engines, on a tugboat, and they are the same as those used in many of the freight train engines. We use about 200 gals/hour with a full load push, but are moving over 4,000,000 gallons of gas at a speed of about 10 mph. Not really efficient, but effective for moving huge amounts of product.
Just trying to put some of this into perspective.
Bill, Claudia, and the Paps
DH Bill / DW Claudia / DD Jenn / DS Chris The Paps! Sophie, Abby, Brandy, Kahlie and Annie
2000 Winnebago "Minnie" 31C, Ford V-10
Purchased April Fools Day, 2008 The Pets
Solar powered feed system for the coal to feed my steam turbine running a gen/set to power the electric twin axel variable speed belt drive system-need twin axels to support the 6 ton coal hopper, makes me think of the movie-Wild Wild West
I work on these (16-Cylinder, Supercharged, 1950 HP, EMD) engines, on a tugboat, and they are the same as those used in many of the freight train engines. We use about 200 gals/hour with a full load push,
Actually 1950 HP is a bit small for a railroad locomotive these days. But if you use 200 gal/hr to generate 1950 HP then you would use 3.1 gal/hr to generate 30 HP at the same efficiency. This is the HP CAT says is needed to run a passenger car at 70 mph. At 70 mph my VW Passat TDI gets 38 mpg and so it is burning 1.8 gal/hr. So the railway locomotive engine, or one similar to it, is actually less efficient than my VW Diesel but perhaps not so much different if you had the gal/hr numbers for both at the same percentage of full HP. Either way 200 gal/hr is not inordinate when you consider the HP being generated and nobody is suggesting that MH's would be more fuel efficient if only they had 2000 HP engines. Quite the opposite really.
I work on these (16-Cylinder, Supercharged, 1950 HP, EMD) engines, on a tugboat, and they are the same as those used in many of the freight train engines. We use about 200 gals/hour with a full load push,
Actually 1950 HP is a bit small for a railroad locomotive these days. But if you use 200 gal/hr to generate 1950 HP then you would use 3.1 gal/hr to generate 30 HP at the same efficiency. This is the HP CAT says is needed to run a passenger car at 70 mph. At 70 mph my VW Passat TDI gets 38 mpg and so it is burning 1.8 gal/hr. So the railway locomotive engine, or one similar to it, is actually less efficient than my VW Diesel but perhaps not so much different if you had the gal/hr numbers for both at the same percentage of full HP. Either way 200 gal/hr is not inordinate when you consider the HP being generated and nobody is suggesting that MH's would be more fuel efficient if only they had 2000 HP engines. Quite the opposite really.
Ken
My point exactly. The manufacturers have pretty much got these engines and RVs set for the best combination of power and efficiency that they can get with todays equipment. Things will probably improve in the future, but for now, we're stuck with what we have. We have the chance to save some fuel with solar panels and such, to reduce the need for our generators, but as far as operation of the RV drive train, we're petty much stuck!
As for the trains, yes, they have more powerful engines. Usually turbocharged, where mine just have supercharges, but they are similar engines (EMD 16-645-E6).... also, some trains have 2-engines in a single locomotive, to get the extra power....and of course, there are often 4-5 locomotives on a single train, depending on the number of cars they are moving.
davemittan wrote: I've occasionally lurked on a British motorhome forum - their motorhomes are usually on a Fiat, Peugeot or other chassis with diesel engines that are 2.5L or less. They are saying they're getting over 20 mpg. But their rigs are tiny by our standards, and it sounds like they're really grunting going up hills.
They cope with their conditions and what they have.....
Correct. They have serious performance issues they trade for fuel economy. If you get caught behind an RV in Europe (my experience is in the UK) you are in a world of hurt. The real fun ones are the "caravans" (camper trailer) towed behind their cars which invariably are grossly underpowered for the task at hand. The RVs are very light compared to ours to....no big tanks, cassette toilets, etc.
You can get an idea of "caravans" here if you are a Top Gear fan (or want to be): http://youtube.com/watch?v=0GZRmzuiig8
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But I suppose most folks will put it down to some sort of conspiracy theory..jpg)
