Idea for simple leaning Delta Trike

I've been toying with the idea of a leaning delta for a while. I don't want it to flop over at a stop, and while some of the mechanisms I've seen for locking upright are simple, avoiding them all together would be nice.

I found a pair used full suspension bikes that I can pick up cheap, and my thought is to put a hub motor in the swingarm of each and mount the swingarms side by side as close together as possible sharing a common axle at the pivot point. Then leaning, at least up to 30-40° for turns would be accomplished via compression of the suspension on the inside of the turn and extension of the one on the outside.

I realize it won't be the most efficient in terms of weight, but I love the simplicity. The only issue I see is that some weight shift may be necessary to ride upright on a cambered road surface. Anyone see any other problems?

John

John, I think that might work. I had the same thought a few days ago, looking at a Vespa style scooter with a hub motor. I actually got three of them over the last 1 1/2 years just for the motors and controllers, which I used to build the pusher trailer for my delta trike. I don't have any use for such a rig, and I've promised the only frame I have left to another member, but just attaching two swingarms via an extra long axle and then using one shock/spring on each swingarm should allow just what you are talking about. Think I'll set it up while I still have the frame here just to see what it feels like, probably just in a stationary position.

Edit: Next morning: Oops, this would not work without a "left to right" pivot point at the rear. I.e., if you leaned to the right the left wheel would have to raise, without a pivot point. Then you are right back to the problem of how strong the springs need to be to keep the bike upright, but still allow you to lean.

The solution I like the best is to have one hand lever control the steering, and the other to deal with the tilt - such as used on the Tripendo...

http://www.tripendo.com/EDEFAULT.htm


[youtube]NKW9umqbI4k[/youtube]
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michaelplogue said:

The solution I like the best is to have one hand lever control the steering, and the other to deal with the tilt - such as used on the Tripendo...

Click to expand...

I can see how that could be fairly simple on a delta, and work well once you get used to it, but if I go to 1 hand stick steering then I'd want that same stick to control lean too. ie free up a hand for a relaxed ride, not force 2 handed attention at all times.

John

something like this maybe?



he even modifiesd a motorcycle with this idea.

rick

Rick,

Thanks for that pic. That leaning motorcycle drawing is like what Bram Smit came up with as shown here http://www.fastfwd.nl/index.php?id=36. I was thinking to go really simple to put something on the road, but the leaning motorcycle drawing gives me some ideas that are pretty simple.

John

in case you are interested here is a complete PDF copy of his patent. he includes several drawings of various arrangements for the links and shock.

rick

You may be interested in this John: http://endless-sphere.com/forums/viewtopic.php?f=12&t=2863&p=40651&hilit=shredder#p40651

I'd also suggest doing a search for posts by member Stevil_Knevil. He built something similar to what you describe, but used a pneumatic damping system to link the two swingarms.

I've thought a bit about building a tilting tadpole trike, but not got much further than thinking yet. Mine was a purely motorised design, as your feet would be used to provide tilt control via a pair of pedals - so to prevent the trike from flopping over you would have to apply equal pressure to both pedals. The idea was to make the system as intuitive as possible.

There is a Yahoo discussion group dedicated to tilting vehicles that is 7 years old. I recommend joining and reading it.

I will say that I looked seriously at a tilting tadpole design a couple of years ago. There is at least one excellent design that is simple and has only one flaw that is relatively easily remedied. If you are interested, let me know and I'll post the patent PDF. There are some relatively amazing videos of this design in action, as well, on YouTube.

wanders said:

There is a Yahoo discussion group dedicated to tilting vehicles that is 7 years old. I recommend joining and reading it.

I will say that I looked seriously at a tilting tadpole design a couple of years ago. There is at least one excellent design that is simple and has only one flaw that is relatively easily remedied. If you are interested, let me know and I'll post the patent PDF. There are some relatively amazing videos of this design in action, as well, on YouTube.

Click to expand...

Yes please post the patent PDF for the tadpole tilter. i also very interested. i have also looked at and thought of building one. i've been a member of the tilting group for a while now. but only as a lurker - not a poster.

rick

I'd love to build a tadpole tilter, mebbe out of a cheap dozen year old 150hp sportbike..

Rick Wianecki's Leaning Tadpole Trike Project (w/drawings and construction snapshots.)

http://www.recumbents.com/WISIL/wianecki/leaning_trike.htm

Wayne SooHoo's Aileron Trike (tadpole)

http://www.maxmatic.com/soohoo.htm

Stevil Knevil's Ilean used a pair of air cylinders that were cross connected by a tube. This allows air to pass from one side to the other. Apparently they were made from used Cadillac air shocks that were drained of oil. It gave a very smooth ride and handled very nicely in corners. By applying the brakes to both rear wheels, it would stand up by itself. No kickstand needed.


A leaning tadpole would be really cool.

Thanks guys,

I've seen most of those trikes before. It took a while for locking rear brakes locking the lean on Stevil's delta to soak in but I got it. I don't get the tadpole fixations though. I don't want go-kart type low, I like simple, full suspension is mandatory, and I see long wheelbase as more benefit than detriment. So what if I occasionally need to lift the front wheel in tight quarters. I do that already with my 115lb ebike, even lifting the whole thing on occasion.

Unless I'm missing something, about the only real benefit I see for tadpole is that a better teardrop shape is possible for aerodynamics once you go full fairing. I just can't see myself putting in the required years of tinkering to get front suspension and leaning accomplished to nail the tadpole. On the other hand, lean and suspension are straight forward on a delta, and playing around with rake and trail are easy enough. Plus going with dual hub motors on the rear will get me all the power and speed I need for now, since just one gets me up to 50mph with a long enough straight away and up 10° grades without pedaling. 2 of those hubbies plus increasing voltage from 63v nominal up to 74v or 85v, should make for a reasonably fun ride that I can even take on the highway, which with good controllers will still be bulletproof dependable as long as I don't go for drag racing amperage.

John

FWIW, the creator of the Jetrike has pix and pdfs of numerous leaners and their patents (bottom of page):

http://www.jetrike.com/prior-art.html

John in CR said:

I've been toying with the idea of a leaning delta for a while. I don't want it to flop over at a stop, and while some of the mechanisms I've seen for locking upright are simple, avoiding them all together would be nice.

Click to expand...

Henry Thomas's Jetrike is one of the few deltas I've seen that incorporates self-centering tilt, sans the mechanical tilt lock. There is a few limitations in his design however; The geometry is exacting and is ill-tolerant to CoG changes much higher than about 500mm (assuming a seat height of about 250mm (9.8")). This also applies to the CoG's longitudinal position (i.e. forward biased CoG seems to inhibit or reduce the self-centering effects). The excellent open source plans are quite detailed and freely available via download from his web site http://www.jetrike.com/plans.html

John in CR said:

I found a pair used full suspension bikes that I can pick up cheap, and my thought is to put a hub motor in the swingarm of each and mount the swingarms side by side as close together as possible sharing a common axle at the pivot point. Then leaning, at least up to 30-40° for turns would be accomplished via compression of the suspension on the inside of the turn and extension of the one on the outside.

Click to expand...

The individual swing arms should be mechanically linked and properly synchronized. If self-centering (no tilt lock) is desired, then the refined geometry that Henry Thomas has carefully detailed in his plans should be follow to achieve it.

If you want a simpler approach, then Tim Hicks "Black max" tilting delta http://www.fleettrikes.com (the black trike below), or Paul Sims (the red trike pictured below) might be more to your liking. Both of these designs incorporate mechanical tilt locks, IIRC.

Tim Hicks - Black Max


Paul Sims - delta

Thanks Papa,

Fleet Trikes is an info packed site I haven't visited before, and that Black Max is really cool and looks pretty simple with tons of info shared, but I think I want to go with a swing arm approach, because 1. I'm going with a 1200W hub motor in each rear wheel, so any kind of stub axle is out and 2. With swing arms that pivot up and down around a shared axle, simply holding the rear brakes will give me enough lean lock to balance at stop signs and such, though I do realize I'll also need some kind of mechanical lean lock. I want to keep it simple, since I may very well end up back at an enclosed 2 wheeler with retractable "landing gear" similar to what some velo's use.

Regarding the jetrike page, since the maker wants to go back to tadpole, there must be a flaw in the application. Also, it's too exacting and I want to ride higher, so self balancing is out. It may be something to try someday, but not as a first attempt. I want to lean and steer like a 2 wheeler anyway, and I worry about fighting against a self balancing effect.

John

John in CR said:

Thanks Papa,

Fleet Trikes is an info packed site I haven't visited before, and that Black Max is really cool and looks pretty simple with tons of info shared, but I think I want to go with a swing arm approach, because 1. I'm going with a 1200W hub motor in each rear wheel, so any kind of stub axle is out and 2. With swing arms that pivot up and down around a shared axle, simply holding the rear brakes will give me enough lean lock to balance at stop signs and such, though I do realize I'll also need some kind of mechanical lean lock. I want to keep it simple, since I may very well end up back at an enclosed 2 wheeler with retractable "landing gear" similar to what some velo's use.

Regarding the jetrike page, since the maker wants to go back to tadpole, there must be a flaw in the application. Also, it's too exacting and I want to ride higher, so self balancing is out. It may be something to try someday, but not as a first attempt. I want to lean and steer like a 2 wheeler anyway, and I worry about fighting against a self balancing effect.

John

Click to expand...

All 3 of the deltas I listed above are ridden and feel like 2-wheelers.

Re. Henry's Jetrike;

I have validated much of Henry's work and found NO flaws - only the limitations I stated elsewhere which is documented on his site. If flaws did exist, I am confident he would not have released the plans without so stating (as evident by his revisions). IIRC, he too (Henry) expressed concerns about being seated too low, and decided to explore free-to-caster tadpoles. I've had a few one-on-ones with Henry, and there is little doubt he is one sharp cookie.

In sifting through my tilt collection, I happened across the image below. I don't remember where or exactly when I acquired it (seems about a year ago), but will happily pass along any additional info when my foggy memory decides it's time. Note: Judging from the shape of the bell crank and the pivot locations of the synchronizing linkage, it does not appear (from this image, anyway) that this trike has self-centering.

Thanks, that last one looks to be most like the Frankenstein I'll likely end up with as a first try. I think I've got my brain wrapped around how self centering works, so if they still ride like a 2 wheeler, I'll put some planning time in to shoot for neutral or better before any bike cutting or welding. I'll also have the advantage of flexibility in battery placement, so mounting that 30-50lbs below the roll axis in a manner that tilting lifts the battery CG can give me a self centering of the trike alone. Even if it doesn't self center with rider aboard, that will probably still be enough to easily balance at short stops.

John

If the trike is to lean into bends, maybe the seat should be made as high as that of a minivan.