Recumbent Tadpole Trike: Posts on Velomobilforum p.2

First post to the Velomobilforum is about a potential tilting mechanism for the trike that a friend of mine and I imagined while chatting at work. See below.

Hello everyone, first as can be seen I do not speak German. So introductions, my name is Ceeann and my forum name is ceeone. I am 56 ,female, and married. I seem to be in a minority for self builders but I have wanted to build a trike for some time and I have become enthused with the idea of building the spaceframe trike along the lines of the n55. From what I can tell this is THE forum for builders of the n55 type trike. As I have been absorbing the design for the n55 and looking at all the upgrades and modification all of the members here have been posting I have had a brain storm or two myself.

First I would like to repost a build picture that Trikelike posted on 20.01.2017

I really liked this design for the cross member of the trike due to the inherent stability this equilateral trapezoid should show for framework. After seeing the implementation for zero point steering I started loving it. But when I showed this picture to my friend Kristopher Marek the first thing he asked was if the trike tilted. I looked at the picture and saw what he meant. So here is the big idea and why I really love this geometry!

If one where to put bearings at the 4 corners of this frame where the horizontal tubes meet the dual side tubes the entire structure will pivot. Now bolt the bottom cross tube into the spine of the trike but leave the top unattached. This will allow the wheels to tilt depending on where the structure is rotated. So there is a tilting trike! The rest is fairly straight forward.

Since the trike should only tilt while in curves the frame can be stablized with a brake anchored to the spine of the trike and applied to the trapezoid frame. No doubt some sort of modified disk brake would work the best. Attach this brake to a handle with a lock and it is ready to lean through a curve at speed.

I really wanted to share this brain storm with all of you and get your input.

Ceeann (aka ceeone)

and now with google translate.

The other part is at
https://www.velomobilforum.de/forum/index.php?threads/eigenbau-xyz-spaceframe-vehicle.33109/page-24



Next are the replies.

Hello Ceeann,

Zitat von Ceeone: ↑

Hello everyone, first as can be seen I do not speak German.

that is not the slightest amount of a problem for most of us, welcome to this forum! 

Zitat von Ceeone: ↑

If one where to put bearings at the 4 corners of this frame where the horizontal tubes meet the dual side tubes the entire structure will pivot. Now bolt the bottom cross tube into the spine of the trike but leave the top unattached. This will allow the wheels to tilt depending on where the structure is rotated. So there is a tilting trike! The rest is fairly straight forward.

A good idea, indeed. There might be one problem with the type of stabilization: If you only attach the main frame to the lower tube then the whole system might start to wobble or get progressively more unstable as the wheels are not fixed but steerable. This might even lead to infliction of effects to the steering itself, no matter if you drive straight forward or around a corner/curve. The low point of hanger gravity (during to the fixed lower tube) could help a bit but not that much to stabilize the whole system completely in every situation of use.

To stabilize this there is more needed than just a brake fixing the whole tiltable front wheel axle: I would suggest that there is a direct possibility to adjust the position over the steering rod/tiller/handlebars, whatever. This way you can stabilize and tilt it over the muscle power itself and keep it upwards even in an array of quickly following steering or driving actions.

The brake for fixation is still a good idea which makes it ways easier to stand up/sit down and park the trike.

Best regards
Wolf

 

And a second reply

 

 
Hi Ceeone,

Zitat von Ceeone: ↑

Since the trike should only tilt while in curves the frame can be stabilized with a brake anchored to the spine of the trike and applied to the trapezoid frame. No doubt some sort of modified disk brake would work the best. Attach this brake to a handle with a lock and it is ready to lean through a curve at speed.

Just an spontaneous thought ... upon releasing the tilting brake at high speed, there might a some kind of sudden transition that could upset control. For example, you might have a slight steering deflection already because the road leading to a curve is not entirely straight, then you release the tilting brake in anticipation of the curve, and due to the already existing centrifugal force, you suddenly and unintentionally lean to the outside of the turn.

On standard tilting trikes, the brake is only used to prevent "capsizing" when stationary, or in some cases at low speeds mainly for convenience, avoiding the balancing otherwise necessary. (At least, that's what I read. I have not ridden a tilting trike, though I have to admit I once "capsized" a non-tilting one ;-)

Zitat von Ceeone: ↑

I seem to be in a minority for self builders

Coincidentally, the recumbent bike in my avatar picture is the design of a female builder, Juliane Neuss, who has come up with quite a number of innovative ideas, some of which made it into small series (like my folding recumbent conversion), or even into mass production (thought that's an upright bike, not a recumbent).

Regards,

Hein

 

At this point I replied from work in a very hurried post before work... see page 3.

 

P.s. The crash I experienced for this blogger page may well have been due to my using the last version of internet explorer (NOT apologies to Microsoft internet explorer). I switched to Firefox and I have experienced no new issues... oops as I tried to save and post this it would not work. After reading up a little this is due to the add blockers in this Firefox edition that I added on the browser. Little did I know... they are now disabled for Blogger and hopefully now things will work. Nope! It turns out that blogger is not a wysiwyg kind of text editor. In order to drop in a picture one can not just drop them in with text from a word processor. One has to insert an image from the tools bar... fyi!

 

Ceeann ttfn