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Boe-Track

Planes with Wings
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Flight is awesome. There is no rolling friction with flight, just air friction.

The only problem with flight, is that you are so high in the air, you can’t touch the ground and push yourself forward. And so you are stuck with pushing air backwards, to make yourself go forward with a propeller or jet engine.

So what if you could combine the advantages of a train and a plane? What if you could use wings to reduce rolling friction between the train and the tracks, between the bearings, and gears of the train? You have wings, but you stay on the ground so you can push against a solid surface (the earth), instead of trying to push against air.

I think the best way to explain my idea is a thought experiment. Let us say you load a train and a plane with 250 tons of cargo in Las Angeles. Then you have the train drive its cargo to New York. The plane flies its cargo to New York. Which method will use the least amount of gas? I don’t care. What I’m interested in is the return flight.

You load the train and the plane with 250 tons of cargo again. Then you put Evil Kanevial Jr in the cockpit of the plane, and tell him he is not allowed to turn on the engine, but he is allowed to move the Ailerons to keep the plane from crashing. Then you tie a cable from the train to the plane. You pull the plane (with 250 tons of cargo) in the train (with 250) tons of cargo back to Las Angeles.

My question is this: which trip took the most amount of gas. If I am right, the return flight would have taken less gas, because it combines the advantages of lift, with the advantage of pushing against the ground to move yourself forward, in a train, instead of having to push against air, in a plane, to move yourself forward.

My idea is to save Evil Kanevial a lot of stress, and design a train with wings, recreating, in essence, the thought experiment explained in the trip from New York back to Las Angeles. However, when planes fly near the ground, or near the water, the lift is improved, because the air is compressed against the ground or water, producing even more lift.

My idea would have the wings producing more than 250 tons of lift (the weight of the plane and the cargo), so the track, gears, and bearings only see 250 tons of weight.

myclob, Jun 28 2009

Maglev http://en.wikipedia.org/wiki/Maglev_train
[swimswim, Jun 28 2009]

Ground effect train http://en.wikipedia...Ground_effect_train
Baked it seems [Twizz, Jun 29 2009]

Working prototype http://www.ifs.toho...rain_outline-e.html
Baked as a bean. [Twizz, Jun 30 2009]

Laur monorail airplane http://upload.wikim...f/Laur_monorail.jpg
"Is it practical? Maybe and maybe not." [jutta, Jan 14 2014]

[link]






       So, the question is, how much energy is expended in overcoming rolling resistance? My guess is that it amounts to less than 2% of the total energy expended by a heavily-laden train over a long distance. And advance on that?
MaxwellBuchanan, Jun 28 2009
  

       Would this be cheaper than a maglev train? Using the cost-benefit analysis of which you spake.
swimswim, Jun 28 2009
  

       Won't work. Period. The energy required to lift the weight will be greater than any energy saved in friction reduction, because wings are inefficient producers of lift - turbulence and drag as a side-effect. The mass of the train is unchanged, even if it were carried on a wing, so no energy savings on acceleration either.
sstvp, Jun 28 2009
  

       re: "The mass of the train is unchanged, even if it were carried on a wing, so no energy savings on acceleration either."   

       No one said the mass would somehow be changed. Gravity pulls the train down putting stress in the gears, on the track, in the wheels, and in the bearings. The wings would produce lift. Gravity pulling down. The lift pulling up. The same mass, but the train track would feel less weight, because the lift, lifts a portion of the weight upward.   

       re: "Won't work. Period. The energy required to lift the weight will be greater than any energy saved in friction reduction, because wings are inefficient producers of lift - turbulence and drag as a side-effect"   

       Its my idea, and I only give it a 2% chance of working, but I think you are a little strong when you say: "Won't work. Period." I think I would like to see some calculations from someone before we say that we are SURE. Lets just agree that it probably won't work, but I think it would be cool if it did.   

       This is my argument: If wings are "inefficient producers of lift", who do we fly planes?   

       Wings are efficient producers of lift. And lift is so cool, because it overcomes the problems of rolling friction. Wings are such great producers of lift, and do such a great job of overcoming rolling friction, that we put up with crappy forward thrust producers on plans, like propellers and jet engines.   

       Propellers and jet engines are crappy producers of forward thrust, or else we would use them on trains. Wings are excellent producers of lift, or else we would all just drive trains everywhere. If we can use planes to overcome 1/2 of the rolling friction, by putting wings on trains, we could have the best of both worlds: reduced rolling friction (that is proportional to the weight being carried), and great forward thrust production from standard train mechanisms.   

       Do a though experiment. Imagine a train pulling a 747 by a long cable from Las Angeles to New York. The train and 747 both carry the same cargo, lets say they each carry 250 tons (the pilot does not turn the jet engine on, but moves the wings to keep the plane from crashing). I believe the gas used by the train pulling the 747 would be less than if the plane flew itself, and the train drove itself. If so, than that proves my idea is a good one. Because you could use the same mass of the plane and train, but have a bigger train with wings, throw away the extra parts, have the same thing as a train pulling a 747...
myclob, Jun 29 2009
  

       Minor problem. 747 efficient cruising speed, mach .8 or ~850 kph. Take off speed of the same 747 ~290 kph. Best high speed train to date ~220kph.

Admittedly the absolute minimum needed for a loaded 747 to take off appears to be down around 188 kph, but only under ideal conditions. As such, you are going to have a hard time getting this train to provide enough lift.

Oh, and as to why we fly things, its because its fast, not because its efficient. A train, on flat ground, at a constant speed, is by far the most fuel efficient transport mechanism ever devised (with the possible exception of a bicycle under the same conditions).
MechE, Jun 29 2009
  

       I'm gonna take the existence of WIG's to postulate that lift-drag isn't as much as hull-drag, but as previously noted, trains are pretty awesome in efficiency department.   

       //I think I would like to see some calculations from someone before we say that we are SURE//
okay.
FlyingToaster, Jun 29 2009
  

       I do this every time. I have a throw away idea, but when people start talking about it I really start defending it...   

       re: "You'd lose traction and power with this, due to the lift."   

       Trains have plenty of traction. They could loose 99% of their weight and still have enough "traction". When the train is going slow, and wants to speed up or slow down, there would be no lift. Even at 60 miles per hour, the train would not have "traction" problems. Even if it did, just rotate your Ailerons and you have all the traction you want.   

       re: "Minor problem. 747 efficient cruising speed, mach .8 or ~850 kph. Take off speed of the same 747 ~290 kph. Best high speed train to date ~220kph" I'm not saying we use the exact same wings as a 747. I have not done the calculation. I do not have a wind tunnel. But you have identified the whole question. If a wing can produce very much lift at 60 miles per hour.
myclob, Jun 29 2009
  

       //Best high speed train to date ~220kph//
I've clocked a Eurostar at over 300.
coprocephalous, Jun 29 2009
  

       Is this making anyone else want to parasail?   

       //Is this making anyone else want to parasail?//
Above/behind a train with an overhead 25kV pickup? No thanks.
coprocephalous, Jun 29 2009
  

       See link - I was sure I'd seen this somewhere before. I'd guess it would ideally run on a concave track (like a drainage channel) so as to gain lateral location as well as support. Traction would not require the weight of the vehicle if it used pairs of wheels clamped to a central rail. Clamping force could also be adjusted according to the tractive force required. Tunnels should present no problem, so long as the train is properly designed.
Twizz, Jun 29 2009
  

       What if there were a long rope connecting New York and Los Angeles with a mile or two of slack in it? Then the aeroplane could take off and fly as usual, but with the rope continuously passing through a pulley on the aeroplane. Then the power of the engines could be used to pull the aeroplane along the rope, which must be a more efficient use of power than pushing air out of the way, surely?

(Yes, I realise I'm ignoring the massive weight of the rope, the unfeasible strength of rope needed, and the plight of millions of midwesterners who'll have this huge rope dropping on their heads every day)
hippo, Jun 29 2009
  

       //I'm gonna take the existence of WIG's to postulate that lift-drag isn't as much as hull-drag, but as previously noted, trains are pretty awesome in efficiency department.//   

       Actually, at the point of least total drag, form drag and induced drag are about the same. (Wikipedia: Drag). As Rolling friction is negligible compared to aerodynamic friction (form drag) in trains, and the wings would add induced drag to the amount of form drag, the idea is bad.
loonquawl, Jun 29 2009
  

       //Above/behind a train with an overhead 25kV pickup? No thanks.//   

       as long as you aren't grounded...   

       What would be easier, pulling a kite all rolled up on a skateboard behind you, or pulling the kite unfurled in the air behind you? Especially at high speeds.
swimswim, Jun 29 2009
  

       sp. - Evil Canaveral   

       // Trains have plenty of traction. They could loose 99% of their weight and still have enough "traction". // False statement. The amount of pulling power that a locomotive can apply to a train is, at best, about 1/4th the weight of the locomotive (that being the coefficient of static friction of steel on steel). That figure can drop to 1/10th in wet, icy, or cold (even with no water, the steel gets harder & less adhesion) conditions.
lurch, Jun 29 2009
  

       My mistake, I found a bad source for train speeds. It's possible you could get a train above lift speed, but still not up to a real cruising speed.

  

       Finding the right of way without bridges and overhangs to do that in the US is improbable at best. It might be possible in sections of the midwest, but the rockies would be difficult, and the east coast corridor would be impossible without a lot of political will, as it would require truly massive uses of eminent domain and construction money. (There's a reason we don't have anything faster than the Accela there already, the right of way just isn't available)
MechE, Jun 29 2009
  

       wikipedia: "The A-10 has superior maneuverability at low speeds and altitude, thanks to large wing area, high wing aspect ratio, and large ailerons. The large high aspect ratio wing also allows for short takeoffs and landings, permitting operations from rugged, forward airfields near front lines. The aircraft can loiter for extended periods of time and operate under 1,000 feet (300 m) ceilings with 1.5-mile (2.4 km) visibility. It typically flies at a relatively slow speed of 345 mph"   

       We would have different wings than the wort-hog, designed for 60 miles per hour.
myclob, Jun 29 2009
  

       Hmm, no one has mentioned tunnels which would cause big problems...   

       In any case, as others have mentioned aerodynamic drag is much higher than rolling friction especially a train's steel on steel rolling friction when you have given up the planes slight advantage of flying high in thinner air.   

       So if you were crazy enough to do this there would be an advantage over flying but much less efficient than a train alone.
MisterQED, Jun 30 2009
  

       And all the things that make a warthog capable of flying at low speeds also make it an inefficient flyer and a fuel hog. Low speed, low altitude flight is inefficient, although you might recover some of that through ground effect.
MechE, Jun 30 2009
  

       From what I find, the A-10 is very efficient... but that is not my point... my point is that we can make similar decisions to those they made for the A-10. "thanks to large wing area, high wing aspect ratio, and large ailerons" the A-10 is able to get lots of lift at low speeds. That is my point. You can make deign decisions that maximize low speed lift. There is nothing to argue, I'm not saying it is a good idea. I am not saying it will work. I'm just saying if it does work, it will be the result of maximizing lift at low speeds.
myclob, Jun 30 2009
  

       //I'm not saying it is a good idea. I am not saying it will work.//[marked-for-tagline]
FlyingToaster, Jun 30 2009
  

       Will the series of exercise videos be available first?   

       Tae-Boe Track.
normzone, Jun 30 2009
  

       //the wort-hog//
A beer-drinking pig?
coprocephalous, Jun 30 2009
  

       no. anyone who thinks that this is a good idea is completely uninformed as to the nature of friction and the energy consumed to produce flight.
WcW, Jun 30 2009
  

       The original idea mentions ground effect, which is more effecient than proper flight and has sufficient potential that prototypes have been buit and tested (see link).   

       Anyone who thinks this is unworkable is completely uninformed as to the nature of ground effect. ;-)
Twizz, Jun 30 2009
  

       to reiterate : at point of lowest total drag, airplanes have 50/50 form and lift drag. trains have just form drag, with rolling 'drag' negligible. if trains fly, the lift drag will be as big as form drag -> bad idea.   

       ground effect leads to max 3x reduction in induced drag, so no joy there.   

       adding: the lower the velocities, the higher the lift drag, part of the explanation why the 'warthog' is a fuel guzzler.
loonquawl, Jun 30 2009
  

       The Japanese and French prototype ground effect trains (linked to from the Wikipedia article) are both pushed by propellors rather than wheels, so they don't quite make this idea baked.   

       A similar concept has been used with barges, where the propulsion comes from a person, animal, or vehicle on a towpath (pushing against the ground) rather than a propellor or oars on the barge (pushing against the water).
spidermother, Jun 30 2009
  

       I also doubt that they were freight trains. There is a factor of scale and weight here. Bullet and "ground effect" trains can work because their density is relatively low. If they were carrying ore the amount of heat generated by the pressure required to keep them off the ground would completely defeat the system.
WcW, Jun 30 2009
  
      
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