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Wheel-knuckle designed in SolveSpace

February 15, 2025 — BarryK

Continuing learning, constructing various trike parts, this time the wheel-knuckle. Earlier posts:

Had a go at modeling the wheel-knuckle, but hit a problem, as extrusions are at 90 degrees to the work-surface; there is no mechanism to specify an arbitrary angle. I need extrusions to be 80 degrees, just off being a right-angle.

I came across explanation how it could be done, that I didn't understand. So I did it the only way that I could understand, by creating little wedges. This is the end result:

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Intention is it will be all-aluminium, though the wheel-axle could be steel for extra strength. The image is the right-hand-side knuckle. When assembled, the wheel-axle and steering-linkage-arm will both be horizontal, so that the central knuckle shaft will be 10 degrees off-vertical, leaning both backward and inward.

This is an artistic model; in reality those ledges won't be there. The knuckle is the most difficult part of the trike to construct. In my current trike, the knuckle is made mostly of steel, details provided in links here:

https://bkhome.org/nomad/solar-powered-recumbent-trike.html

Actually, have it pretty well sorted out how the knuckle in the above image can be constructed. The axle will just slide into a hole right through the central post, then welded in place.

Anyway, lots of fun, but have to stop. SolveSpace file here.

Here is another YouTube playlist:

"SolveSpace - 3D Stuff"
https://www.youtube.com/playlist?list=PLluslK6uBf4sUY_SgOZhBTb_5Vs-XMHZ6

Great that there are so many videos.

EDIT 2025-02-15:
A "Skew" checkbox has been added to extrusions, November 26, 2024:

https://github.com/solvespace/solvespace/commit/f4cfb60ab5c8dbacd5aea3c4cd33b7e72422dcfb

This enables an extrusion to be any angle, not just perpendicular.   

Tags: light

Universal ball joint created in SolveSpace

February 14, 2025 — BarryK

I'm learning how to create 3D components in SolveSpace, earlier posts:

...actually, after stdying more tutorials, that extrusion limitation is not a limitation; bevels can be created on the extruded corners.

I spent most of today learning how to create a ball-joint. I want a 3D component to represent a flexible joint; ball-joint or heim-joint. It doesn't have to look exactly like the actual physical joint, just close enough to convey what it is. Movement must be in three dimensions, not flexible only in 2D.

Finally got there, this is what it looks like:

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The SolveSpace file is here.

The trickiest thing was to get it to be flexible in three dimensions, not just flex in 2D. The trick was, need to start with menu "New Group -> Sketch in 3D" and create two lines, joined at one end. After that, can use the "lathe" feature to extrude tubes around each of the lines, and a sphere in the middle.

It works! I made the arms approximately matching the 10mm ball-joint that I already own, described in this blog post in March 2024:

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Quite a lot of fun constructing these components; putting them together into a complete trike may be a challenge, and will certainly test just how good SolveSpace is.

There are a couple of nice SolveSpace tutorial-series on YouTube:

"SOLVESPACE introduction"
https://www.youtube.com/playlist?list=PLrNBWyhqEoKESBQIh1dyZpdGR-tyUh-3_

"SolveSpace - Beginners"
https://www.youtube.com/playlist?list=PLGAjLwYQPgaBafzQTLA84IkTOptOdIsUX

What's next...       

Tags: light

3D bottom swing-arm for custom recumbent trike

February 13, 2025 — BarryK

I posted about exploring various 3D CAD apps, script-based then came back to SolveSpace:

...designed the top swing-arm for my custom trike.

If you look at my custom trike project, the swing-arms, also known as A-arms or wishbones, are welded steel and ball-joints:

"Solar-powered recumbent trike"
https://bkhome.org/nomad/solar-powered-recumbent-trike.html

I'm planning to put stiffer springs on the front suspension, and reduce the wheels from 20 inch to 16 inch.

But also there is this germ of an idea to create plans so anyone can build a similar trike, from scratch. Plan for it to be mostly aluminium, including the swing-arms.

Working toward that, want to model the entire trike in 3D.

Haven't taken my trike on any journeys yet, just ridden around locally. Have learnt a lot about the handling, which is why want the stiffer springs -- they are on order. Going around corners, I can see that stability would be improved if the trike can lean into the corner, so would like to implement that on the next build. Either that, or make it a quad.

Can't go off touring on the trike anyway, as having an eye operation soon, followed sometime after by a train journey.

This evening designed the bottom swing-arm in SolveSpace:

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...notice something a bit odd; there are two brackets to which the shock absorber will bolt, a choice of two positions, but you cannot see right through one of the holes. SolveSpace is having some kind of logic problem there. It doesn't surprise me, the complicated mathematics that SolveSpace has to analyze.

The bottom-arm SolveSpace file is here.

Posting this in the "light" category, as it could be the start of an entirely new traveling-light custom-trike project.       

Tags: light

Basket for trike luggage rack

January 10, 2025 — BarryK

Continuing the custom trike project, here is the previous post:

Have now built a "basket" to go on the luggage-rack. It has to be fairly narrow, due to the panniers either side -- although they are below the luggage-rack, they open and expand upward.

Made it from some 25x25x1.4 mm angle that already had, and some scrap masonite for sides and bottom. First photo:

img1

Pretty simple. The side panels are laminated so have water protection. End and bottom panels are raw masonite, so coated them with Bondcrete to weatherseal. Another photo:

img2

If rain protection is required, could make a fabric cover.

Hmmm, wondering when the trike will be ready for a first short tour. Keep thinking of more things to do. Soon...   

Tags: light

Planning to pack panniers in custom trike

January 03, 2025 — BarryK

The custom solar-assisted tadpole trike project continues, now planning to outfit the trike for a first tour. The previous blog post:

Awhile back, purchased four panniers, Rockbros AS-002. Rockbros has a website in Australia, selling these:

https://www.rockbros.com.au/products/rock-bros-rockbros-waterproof-bicycle-rear-seat-trunk-bag-multifunctional-road-mountain-bike-package-pack-pannier

They can also be purchased off eBay, Amazon and Aliexpress. Example of the latter:

https://www.aliexpress.com/item/1005007887951403.html

Want to learn a lesson from previous experience camping in my car; everything got thrown into the back of the car, ad hoc. Then while camping, would want one particular item, and not know where it is, so would hunt through all the gear. This time, want to be highly organised, everything neatly packed in separate containers and logically stored in the panniers.

So, went shopping for clear plastic containers that would fit inside the panniers and could be stacked. At first, the plastic containers that I found were too large to fit inside the panniers. But found one in Bunnings that is a nice fit, then later discovered some in BigW. Bought this from BigW:

https://www.bigw.com.au/product/brilliant-basics-clip-lock-food-container-4-5l/p/248435

...also a couple of others from BigW, but not quite sure which ones from looking at the website. The main requirement was lid dimensions about 18x25 cm so as to fit into the pannier.

Started to pack the containers and allocate to which pannier, in a hopefully very logical fashion:

img1

On the left, throw-over tent, tent to sleep in, sleeping bag, mattress, ground sheet. They will mostly go into the basket that I am building to sit on top of the luggage-rack. That is not very big, so some of those items are going to have to into the panniers.

Leftmost pannier; two 4-litre water bottles, container on top for food. If need to carry more water, bought these:

https://www.aliexpress.com/item/1005007175786335.html

img2

...great, they store very flat, and when filled hold 5 litres each and can be hung anywhere. That gives a total water capacity of 23 litres.

Second-left pannier has tools. These are general tools, as well as trike maintenance parts. Also various tent parts, such as pegs and rope. Those two left-most panniers are the heaviest and will be mounted on opposite sides, low-down.

Moving right, the next pannier has toiletries in lowest container, others are food and cooking gear. The pannier on the right is set aside for electrical and electronic stuff. Quite a collection, including mains battery charger, AC inverter, MPPT controller. Hoping ultimately to be able to slide a small laptop into the pannier also.

It is going to be a tight squeeze, might have to compromise.     

Tags: light

Install auxiliary solar panel in custom trike

January 02, 2025 — BarryK

Continuing the solar-assisted custom recumbent tadpole trike project, I am now at the stage of outfitting it for a proposed first tour. The previous blog post in this project, introducing the auxiliary solar panel:

The challenge was to find somewhere to put it on the trike. The folded panel is 340x525 mm, which is just right, and the reason why I chose this particular panel. Pop-riveted some angle for it to sit on:

img1

...however, had to remove the head-rest, which solved one problem but introduced another. If I had the forethought that an auxiliary solar panel had to be accommodated, back when designing the trike framework, could have placed those vertical black poles supporting the overhead solar panel back a bit. But, have to live with the current situation and remove the head-rest.

The auxiliary panel fits nicely:

img2

There are constraints above and below. Below, there are panniers that require sufficient room to open and put stuff in and out. And above, there will be a relocated head-rest; also the eye-height must be above the auxiliary panel for looking backwards.

There is aluminium tube just behind the auxiliary panel, to which the head-rest will now be attached; however, the diameter is too small. Needed to manufacture a "pipe-shim", and it just so happens that I have a very short piece of aluminium tube with ID that matches; just need to bulk it out to the required OD. Manufactured the shim with epoxy resin:

img3
 img4

...two concentric rings, tipped-in epoxy resin, afterward cut it down the middle with a hacksaw. Note that I used "Utility" brand epoxy from Bunnings, as it is very slow setting. Also considerably cheaper than the other brands. Needs to be mixed thoroughly beforehand, and sets very hard. This Utility product does have a downside; it leaks after usage:

img9

...24 hours after usage, a puddle is forming. Lots of complaints about this on the Bunnings website. I haven't tried storing it flipped with nozzles at bottom.

Anyway, here are the two pieces of the shim:

img5

...why not make the shim entirely out of epoxy? My reasoning at the time is the aluminium inner makes it easier to grip in the vice, for sawing in half. Yes, that went well.

Wrapped a couple of layers of wide electric tape around the aluminium tube, to give the shim something to grip onto, then mounted the head-rest:

img7

The auxiliary solar panel fits nicely:

img8

...there is also enough room in front of the solar panel for the extension cable. I've got a 5.5 metre length that fits in there nicely also. Using "6mm auto" cable, described in blog posts in 2020:

Tomorrow, intend to build a box to sit on the rear luggage rack. It has to be narrow, so that the panniers either side can be fully loaded.    

Tags: light

Testing auxiliary solar panel with custom trike

December 30, 2024 — BarryK

Briliant blue sky this morning, 10.15am, December 30, mid-summer here in Perth, Western Australia. As mentioned in the previous blog post, the intention when at a camp-site is to keep the trike under shade (if available), with the throw-over tent. There will be a cable to small solar panel in the sun to keep the battery topped-up. Previous post:

The problem, though, is where to mount an extra solar panel on the trike? Found a place where a folding panel could fit, then looked around for one that will be within those dimensions. So, selected a panel based on restricted size, not capacity. But, it turned out remarkably well. This is what I purchased, for AU$169:

https://www.ebay.com.au/itm/294677489161

img1

Ha ha, what a joke; it is advertised as "300W". I was amused in one of the comments, someone complained that they bought it because they expected 300W or near. Naive! You have to know that many vendors tell lies, and estimate power output from surface area of the panel. The vendor also claimed "grade-A monocrystalline", which I also doubted, but after testing the panel; yes, high-efficiency cells.

To connect the auxiliary solar panel, an MPPT controller is required (I threw away the PWM controller that came with the solar panel). Instead of unplugging one that is used for the main solar panel, used the extra one that I had purchased, this one:

https://www.aliexpress.com/item/1005007612832046.html

...it was AU$48 when I purchased it, now gone up a bit; but the AU Dollar has fallen compared with US Dollar. The reason I purchased this was due to curiosity, after having purchased the Lensun MPPT controller:

...the MPPT controller direct from China was less than half the price. Today, finally tested it, and it works great. I attached Anderson connectors:

img2

Plugged into the "48V" lithium battery:

img3

Good result; 86W, more than I expected!

Also useful while touring and stopped for awhile, can get out the auxiliary solar panel and have two panels charging the battery, while eating lunch or whatever.

EDIT:
Found another alternative to the Lensun MPPT controller. This is a brand-name product, with English printed on the controller (and the User Manual is probably in English also). Also cheaper, AU$48 postage-free:

https://www.aliexpress.com/item/1005008269117932.html

Looking around on Aliexpress, also discovered there is another variant with a maximum input voltage of 65V (the above is 50V).    

Tags: light

Throw-over tent for custom trike

December 29, 2024 — BarryK

Continuing the custom recumbent trike project, here are recent posts:

Currently planning the details for going touring with the trike.

It is envisaged at a campsite, the trike will be parked in the shade, and I will use a small folding solar panel to keep the battery topped up -- more on that in a future blog post. While at a campsite, or for whenever there is rain, I constructed a throw-over tent. I have left-over 10D ripstop silnylon fabric from the tent-making days in 2021, and one long piece of orange fabric:

img1

This tent is contructed entirely by glueing, no sewing. Sewing 10D silnylon is a nightmare; so incredibly stretchy and slippery.

I described the glueing technique back in 2021, for example here:

"TreeHugger 1P tarp weighs only 178g"
https://bkhome.org/light/treehugger-1p-tarp-weighs-only-178g.html

Proceeded to add sides and tie-outs:

img2

...photo taken in my loungeroom. At a campsite, the area required for pegging is large but that is not usually a problem. Pulling it out with pegs is important for a couple of reasons. One, so that wind will tend to flow over. Two, to give some room inside.

The 10D silnylon is translucent, so put an extra layer on top to cut down light getting through to the solar cells. 10D is very thin, a tent specialist fabric. I bought most of it in 2021 off Aliexpress, but that vendor is no longer in business. Searched Aliexpress, could not find silicone both-sides ripstop nylon fabric -- the closest is silicone one side, PU the other.

Silnylon is very special. It is silicone impregnated, right through, not just a coating on the sides. It bonds extremely well to silicone sealant. PU does not. It looks like tent manufacturers are not using silnylon anymore; the main reason, if I recall rightly, is that is stretches when wet.

Back in 2021, I did buy some pure 10D silnylon from a company in Europe, and I just now checked; yes, they still have it:

https://www.adventurexpert.com/product/10d-silnylon-fabric/

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For anyone thinking of building a tent, 10D is a bit fragile; I would recommend go for fabric a bit stronger, say 20D. Unless you need the lightest possible weight and small size.

I manufactured the tie-outs the same way as the mark-3 tent in 2021:

And used 30x5 (30mm OD, 20mm ID) silicone o-rings, from Aliexpress:

https://www.aliexpress.com/item/1005001460667252.html

The tent might need some further construction, but for now ok to use on the first tour.    

Tags: light