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Another look at tilting tadpole trike designs

February 25, 2025 — BarryK

I have started a new project, to build a full-suspension leaning tadpole trike, from scratch. Previous post:

I have been looking at leaning-trike designs over the last couple of years, and had intended to implement it in the current trike build. But, decided it is too complicated, and ended up with a non-leaning trike. Here is the tilting mechanism that I considered, late in 2023:

The problem back then, was could not figure out how to connect the tilt mechanism to the steering arms. Have come a long way since then, and now have a design that is simple and looks like it will work. However, taking a bit of a retrospective look, at what others have done and posted on YouTube...

1: Tilting by balance

Most of these are DIY projects. A few guys have built trikes that rely on balance, like you balance on a bicycle. The entire trike, from the rider back to rear wheel, is free to rotate and relies on the rider shifting weight to keep upright. The two front wheels do not rotate, they stay vertical on the ground. In the last couple of blog posts, posted links to "Graham Makes Stuff" YouTube videos; in Part-6, he attempted a leaning mechanism, and went for the balance method. He used a disk brake and caliper, like this:

img1

There is a lever on top that locks the disk, so no tilting. Once underway, the rider releases the lever, then relies on balance, just like a bicycle. However, Graham's experience was that it was very difficult to stop the trike from just falling over.

On a bicycle, the rider is high, making it easy to balance; not so on a recumbent trike. There are a few of these type of designs, including this one, in the "Metal Machine Shop" channel:

https://www.youtube.com/watch?v=NkPyv3-LZmU

...he also experienced balance problems, and has proposed a "MK2" with higher seating. That will help, but is it enough?

2: Tilting hard-linked to the turning arms

What I mean by this, is that the lean is directly linked to how much the rider turns the steering arms. So, turn the steering arms to go left or right in a wide arc, the trike will lean a little bit. Turn to go around a sharp corner, the trike will lean into the corner a lot.

An example of this is the AR3 trike:

https://www.youtube.com/watch?v=t1sUOtY4fYs

img2

Reports from tests are that directly linking leaning to turning radius is not so good. For example, you might turn the steering to negotiate a very sharp turn, at very low speed, and the trike will lean way over into the corner; potentially causing the trike to topple, especially if the back wheel has luggage above it, causing a rather high centre of gravity -- that back wheel can drag the entire trike over.

The AR3 has another problem, that you can see from the photo; despite being tilting, the width has to be wide, as the entire front assembly pivots. This trike actually got to production, but was not a success.

3: Independent turn and tilt control

There have been a few of these type, DIY projects. The one that I am most familiar with, was made by Martin, who lives in Western Australia. That was his "EATSRHPV" trike, about 9 years ago:

https://www.youtube.com/watch?v=FItR3n-oRd8

img3

...He has posted a series of videos showing construction, and it does seem a bit complicated, but it does work. The steering arms are swiveled horizontally to turn, or moved left and right to tilt. So, independently controlled.

There are some others posted on YouTube that look like this independent control, though construction details and mechanism close-ups are not shown.

Of these, Number-3 is clearly superior.

I have worked out a design for the proposed new trike, that is the same principle as number-3, with the steering arms independently controlling steering and tilting. It is also a very simple design. The plans have already been drawn up on the computer. I keep looking at the plans, wondering if I have missed anything obvious. But, seems OK; full-suspension with correct camber/toe/Ackermann, as well as tilting. Well, we shall see, have parts on order.

EDIT 2025-02-26:
I forgot to mention, there was a Number-2 type that was manufactured in 2014 and was in production, for awhile. It was the "Wild Wave", made by Stein Trikes. Here is a video:

https://www.youtube.com/watch?v=zFv9jWgSOOc

There isn't much information about it, but looking at that video, it seems like Number-2, turning and tilting locked together.

I cannot find any reasons why Stein Trikes discontinued it. Google's "Generative AI" does give reasons, but they are just guesses.       

Tags: light

Fix resize partition in NVME drive

February 24, 2025 — BarryK

I posted about buying a NVME SSD (Crucial E100 480GB), in a USB3 caddy, early February:

The purpose of this purchase was for testing TRIM support.

Yesterday, decided to test writing the EasyOS .img file to it, to test that it will boot OK. I didn't expect any problem, as I have other SSDs in USB caddies and they boot OK -- but, they are SATA drives.

The 'easy-6.6.3-amd64.img' file has two partitions, a 7MiB fat12 esp boot partition, and a 921MiB ext4 partition. The latter is the working-partition, and at first bootup, the 'init' script in the initrd resizes that to fill the drive. The resizing failed.

I don't fully understand, but the gist of the problem is that the MBR and partition-table in the .img file think in terms of 512 byte sector size, whereas the drive has 4096 bytes sector size. This is not normally a problem, but now it has become a problem. I don't know if this problem is with all NVME drives, or just this one. The SSD is plugged in now, as /dev/sdc (after fixing, and successfully resizing, the second partition):

# fdisk -u -l /dev/sdc
Disk /dev/sdc: 447.13 GiB, 480103981056 bytes, 937703088 sectors
Disk model: 0SSD8           
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 33553920 bytes
Disklabel type: dos
Disk identifier: 0xd0a7c76b

Device     Boot Start       End   Sectors   Size Id Type
/dev/sdc1  *     2048     16383     14336     7M ef EFI (FAT-12/16/32)
/dev/sdc2       16384 937703087 937686704 447.1G 83 Linux

The 'init' script in the initrd tries to resize the second partition, where WKG_PARTNUM=2 and Wstart=16384:

 echo -e "d\n${WKG_PARTNUM}\nn\np\n${WKG_PARTNUM}\n${Wstart}\n\nw" | fdisk -u /dev/${WKG_DRV} > /dev/null 2>&1

However, fdisk reports an error, that "16384" is invalid; it wants a bigger number for starting sector (I think, from memory, 65536, which totally mystifies me). However, I found that forcing sector size to be 512 bytes, works:

 echo -e "d\n${WKG_PARTNUM}\nn\np\n${WKG_PARTNUM}\n${Wstart}\n\nN\nw" | fdisk -u -b 512 /dev/${WKG_DRV} > /part2resize.log 2>&1

The partition then does resize and it seems to be working OK.

I don't want to change the .img file to have a GPT, as want it to work on very old computers. This hack fix seems OK.

Here is the github commit:

https://github.com/bkauler/woofq/commit/b92f389fb6eb1e423cfd56d591afcc703d571467

Got a list of things to fix in Easy already; will work through them gradually, in between my much greater interest right now, the new trike project.   

Tags: easy

Planning a recumbent trike built from scratch

February 21, 2025 — BarryK

I posted a few days ago about this proposed new project:

My current custom trike started out as a standard trike that I modified, with front suspension, solar panel, etc. Great, but having got hands-on experience with that, have learnt so much, and now contemplating a new project incorporating everything learnt.

Why not build the trike entirely from scratch? let the imagination run wild! That might seem very ambitious, but I reckon it is doable with basic handyman tools. There are DIY trike plans on the Internet, and YouTube videos of guys showing how they made their trike, but I want a complete rethink.

In the previous post, I put a link to YouTube video playlist "Graham Makes Stuff", parts 1 to 4. Just about everybody who builds something like this, finds that it doesn't  end, they keep thinking of improvements, and they make many changes. Graham is no exception. The year following building the trike, he made a series of modifications, including adding front suspension. See his later videos:

"DIY Trike build part 5. Riding, testing, things I've changed"
https://www.youtube.com/watch?v=Mm20VcANAkw

"DIY no weld trike part 6. More changes, tweaks and improvements"
https://www.youtube.com/watch?v=OhFYDE0yG8M

While I think of it, Ben, the owner of Trisled, an Australian trike manufacturer, the only Australian trike manufacturer, built this for his dad, a one-off:

https://trisled.com.au/solar-mobility-quad/

img1

...very simple mounting of the solar panel. A curved frame and attached with cable-ties. Something to consider.

Designing a trike from scratch, no legacy constraints; this is such great fun! Here is a proposed side view:

img2

There are various objectives, one of which is to get the centre-of-gravity very low. The seat is low, also angled so that the pedals will be quite high -- even high enough that there could be a floor-plate to prevent the feet from falling onto the ground.

The yellow colour is the frame, which will be 50x50x3 square aluminium. The reason for it extending high at the back is for attaching the solar-panel frame. Solar-panel, motor, they will be optional; Plan to build the initial trike human-powered only, so as to keep it simple.

The back wheel will have two shock absorbers, each side of the wheel, to keep the length of the trike as small as possible. Though, the forks will be a bit longer than shown in the above diagram, to allow for greater upward deflection of the wheel.

The front wheels have been moved back, a lot more than my current trike, to avoid the wheels hitting the feet when doing a sharp turn. I still want the trike to be narrow, at most 730mm, so as to easily go through doors. The narrow width is another reason why want to get the centre-of-gravity very low; though, it is not so urgent due to optional tilting.

The green-filled construction is a round rod, at the right end a swivel to which the steering arms will be attached. Now this is very interesting; the steering arms will allow turning left or right, but also control tilt. The two functions are independent; swivel the steering arms to turn left or right, like any normal recumbent trike, move the steering arms to the side for tilt either way.

There will be a simple mechanism to disable tilt, but if it is enabled, you can go around a corner with as much tilt as you want. This is much better than some other tilting trike designs that have tilt directly linked to the turning.

I'm waiting for an eye operation, in the public system here, as I don't have private health insurance. The public health services here in Australia are very good. There is a date set for the operation, but there is the possibility of being called in earlier. So not going on any trike tour or train adventure for awhile. While here at home for the next couple of months, great opportunity to have fun with this next trike project.

The wheel-knuckle, looking forward to building that. It is arguably the most difficult part of the project, but I have it worked out, and can even see how to build it without any welding. Waiting on some aluminium to arrive.    

Tags: light

EasyOS Daedalus-series version 6.6.3 released

February 19, 2025 — BarryK

The Scarthgap-series version 6.6.3 was released earlier today:

Here are the highlights of the Daedalus-series since version 6.6.2:

Download:

http://distro.ibiblio.org/easyos/amd64/releases/daedalus/2025/6.6.3/

Feedback is welcome at the forum:

https://forum.puppylinux.com/viewtopic.php?p=143194#p143194

Have fun!   

Tags: easy

Leafpad and SolveSpace compiled in Easy Daedalus

February 19, 2025 — BarryK

I posted about latest Leafpad and SolveSpace compiled in OE for Easy Scarthgap:

Have now compiled them in Easy Daedalus. They will be in the next release.    

Tags: easy

EasyOS Scarthgap-series version 6.6.3 released

February 19, 2025 — BarryK

Highlights since 6.6.2:

Download:

https://distro.ibiblio.org/easyos/amd64/releases/scarthgap/2025/6.6.3/

Feedback is welcome at the forum:

https://forum.puppylinux.com/viewtopic.php?p=143176#p143176

Have fun!    

Tags: easy

latest Leafpad compiled in OE

February 19, 2025 — BarryK

EasyOS has the Leafpad text editor. This is a gtk+2 application and is a dead project. Easy has version 0.8.15, which was released in 2008. It has a bug; the "Find Next" menu item doesn't work.

I checked, there is version 0.8.19, released in 2022. So, have compiled that in OpenEmbedded, and it will be in the next release of Easy Scarthgap. Don't know if it fixes the bug; hope so.

Here is the homepage:

http://tarot.freeshell.org/leafpad/

...it says latest is 0.8.17, which is wrong.

Leafpad is included in Easy as a simpler alternative to Geany. Perhaps should think of finding a replacement.    

Tags: easy

Folder /files fixed in lockdown mode

February 18, 2025 — BarryK

Alfons reported this problem. I confirmed; in lockdown "mode 1", running totally in RAM with all partitions unmounted, /files was a broken symlink. Fixed, see commit:

https://github.com/bkauler/woofq/commit/bb30c5eca6c1538aa5fb00448e8ed6f8d0200c53

Probably getting to time for another release.    

Tags: easy