Boat tail project based on a single wheel trailer...

[BamZipPow]

Originally Posted by Angel And The Wolf

Unless I use a worn U-Joint, there should be no lash. A pickup U-Joint handles a lot more torque than this light trailer would ever subject it to. I'll have to get around to building the trailer to find out. As I see your's, your linkage allows only up and down motion , but not side to side. If your trailer wheel is on a swivel, you essentially have an extended tail with a support wheel, and freedom of motion only up and down, so the trailer swings out as the car goes through turns, but does not bend around turns?

Correct, my trailer hitch (with adjustable air shocks) only allows the trailer to pitch up and down (x only) with no roll or yaw motion (y or z). Yes, my rear wheel is a swivel wheel with an adjustable air bag spring and soon to have a shock absorber. The maximum extended length of the trailer is close to 7' long. I have to hug the inside of the turn tight in order not to take out anything to the outside of my turn. No, my trailer doesn't bend around turns. I just make sure my rear wheel (pivot point) is close to the apogee of the turn before I make the turn. I can back up without ever worrying about the trailer trying to jackknife.

[BamZipPow]

Originally Posted by Angel And The Wolf

Since my rear wheel is not on a swivel, the trailer should back as easily as a two wheel trailer. I plan to st the trailer wheel so that it tracks as closely as possibly to the center of the differential in turns. I don't know that measurement, yet. Whether to measure from the front axle to the middle of the U-Joint, and then put the trailer wheel axle that far behind the middle of the U-Joint in the measurement, or not. Would take some trial and error.

You can look at how some motorcycles tow a single wheel trailer (non-swiveling wheel). I'm not sure how well they can back up with their trailer setups.

[BamZipPow]

Originally Posted by Angel And The Wolf

Thank you for the details. Mine only exists in drawings. If I ever build it, I'll let you know how/if it works.

You can always build a model to see how well things work out and go from there. A quick skeleton frame from a single 2x4 and a wheel could help flesh out some ideas.

Where abouts are you in Texas? I can always swing by with my setup so it may give you some ideas.

[BamZipPow]

Originally Posted by freebeard

If I had pursued this further, I would have gone toward a Vespa motor scooter front axle, with it's side-arm brake and suspension.

I wasn't sure whether the offset between the horizontal and vertical axis is important to your design or not. I leaned toward an horizontal hinge at the bumper and another hinge at the axle. If it was to fold up, the wheel would be on a 4-bar linkage.

Another possibility might be two vertical hinges, with [a] control arm[s] to control the side-to-side excursions. I'm not sure how that one would back up, it might want to jack-knife.

I'm still not sure the Vespa front fork setup will work in a reverse setup. The shock/springs are designed to compress and absorb the impact from the front. I don't see how well the springs will compress when the force is from the rear.


I would believe that the suspension would have to be more like the trailing rear suspension.

[BamZipPow]

Originally Posted by Angel And The Wolf

True. Thanks for the suggestion.

I'm in Abilene, but I think I grasp the concept. You know, my aim is not more cargo space, but continuing the slipstream down to a license plate sized drag surface, with minimal brake along the sides.

I think in order fer yer setup to work, you'll need to find the center of the rear of the tow vehicle and that's where yer pivot point will need to be in order to not have rotational issues with the rest of the boat tail. I know it be interesting to see how it progresses as you gain more insight and start to build.

[Piotrsko]

Since that looks amazingly like my old tailwheel on the 50 pacer, might I suggest a simple clean and re lube pivot area first? Second add a wee bit of extra pivot nut tightness? I had the wobblies when it was dirty, none when clean.

[BamZipPow]

Originally Posted by Piotrsko

Since that looks amazingly like my old tailwheel on the 50 pacer, might I suggest a simple clean and re lube pivot area first? Second add a wee bit of extra pivot nut tightness? I had the wobblies when it was dirty, none when clean.

Thanks fer the suggestion!

I don't have any flutter issues (that I know of) but thought I'd pass on the information about how to control the flutter if someone else were to produce a boat tail based on a single wheel trailer.

[freebeard]

I was assuming the same direction of travel, maybe a little less caster.


http://ecomodder.com/forum/showthread.php/boat-tail-project-based-single-wheel-trailer-26997-25.html#post559982

Angel And The Wolf — If you're modelling at scale, there are good suggestions at AutoSpeed: AutoSpeed - Zero Cost Modelling of Space-Frames

I've reposted this a dozen time but maybe you haven't seen it. This is a collapsible boat tail for a VW Type II:



It features a rigid floor for the underbody flow and a fabric and fiberglass rod upper. If this had a turn-table like BZPs Dark Aero and a segmented upper structure, then you'd have what you want.

I watched him struggle with a single attachment point at the bumper. You want a wide-based hinge line; and then a high-tailed pant over the single wheel that has a license plate and 3rd brake light on the tip.

[BamZipPow]

Originally Posted by Angel And The Wolf

I will be using the hitch bar that U-Haul installed for me. The measurement I'm not sure of is how far back to put the wheel so that it tracks exactly between the tracks left by the car's wheels. I'd like the wheelbase of the front and rear axles, and the wheel base of the rear axle to the trailer wheel axle to be the same, for looks, but with the actual location of the U-Joint some feet behind the rear axle point, I'm not sure how that would track. Yes, a two by four with adjustable wheel mount bracket.

From my experiences with Dark Aero...

Don't fergit about the Texas lighting requirements.
TRANSPORTATION CODE CHAPTER 547. VEHICLE EQUIPMENT

I'm not sure if you'll have to register yer tail as a trailer or not but that's about $60 a year based on my registration cost fer Dark Aero.

The nose of yer tail will need an inverted cone shaped opening to allow fer articulation of yer attachment point. You will probably need to build an elevated "Z" attachment point coming off of yer hitch receiver...kinda like a bike rack mount so the U-joint attachment can be at a neutral starting point. You will need gussets to keep the torsional forces from bending or breaking yer elevated mount off.

The longer the wheel is from yer attachment point, the smoother the ride will be as short wheel bases ride more harsh than long wheel bases. You might want to think about some sort of suspension as the wheel will transmit every road bump to yer tow vehicle.

Since yer tail will be rather lightweight, it may have a tendency to git moved around quite readily by passing traffic or wind gusts.

[freebeard]

Keep in mind the cross-section of the Prius is squircular, closer to a rectangle than a circle.

When you conceptualize it as a conic or spherical interface, it does allow for longitudinal rotation but unless your U-joint swivels there're only two degrees of freedom. Rather than a ball-and-socket connection you could use flaps on the top and sides, similar to the flaps on vectored-thrust turbojets. Or big truck's Trailer Tail™.

In another thread I posted this concept truck:



It uses a combination of rigid, hinged panels and stretchable infill.