If you could make your trailer have the same frontal area profile as your tow vehicle, and if you could make it tow extremely close to the tow vehicle (with a gap of only a couple of inches), it would cause very little drag.
You could not do this with an ordinary tongue. The secret would be to have the tongue go from the top of the trailer, across the top of the tow vehicle and attach on the roof. If the tow vehicle was a pickup with a camper shell, it would attach at the back of the cab of the pickup. There would have to be sufficient clearance to keep the tongue from hitting the roof of the tow vehicle at the back. For aerodaynamics sake you would want the tongue to be as small in cross section as possible.
It would only work with a small utility trailer. Another advantage would be that it would make the vehicle/trailer combination shorter. If the trailer was very short (say less than 6 feet) it might enable the whole rig to park in a standard size parking place.-- RunVentura, Oct 17 2006 I like the concept, it would work better if you could use 2 tounges though. Place them on the farthest corners of the VEHICHLE (not trailer) and put the ball on the trailer. Every time you turn the tounge opposite of the direction you turn is pushed out. This would also have to be programmed for the legnth of the axil from the vehichle, but I imagine a computer would have to control this anyway. As an added bonus it would be easier to back up as well.-- RXAaron, Oct 17 2006 [21 Quest], I don't see how moving the trailer hitch vertically affects the yaw behaviour (steering) of the trailer. The axis about which the trailer pivots is not changed whether the hitch is at ground level or way up in the air. As long as your pivot and hitch are stiff to reduce the ability of the combination to pitch, you'll have no problems on that front.
[RV], you've just invented a minature articulated lorry.-- david_scothern, Oct 17 2006 This is called a Gooseneck trailer, some places, although those only get the ball/pivot/hitch into the bed of the pickup truck.
The proposed design would allow the trailer to pivot around to the front of the vehicle, which would make backing the trailer a lot easier.-- baconbrain, Oct 25 2006 random, halfbakery