Getting a good fit

After a full day making aluminium tinsel on the milling machine I now have a full set of female molds that make a good job of casting the elastomers. Surprisingly quick if you have access to a 1.25" drill and a micrometer boring head. Actually took longer to halve the stock and square it with the facemill.


Using an old pressure cooker for a vacuum degassing chamber helped keep the bubbles to a minimum. I might try running pressure on a set to see what works best.

Next update: leading link front for the barrow race buggy.

Bring a friend to the dunes

Three BF classics found a new home but first needed a little fitting out to fit in.
New kinked downtube:

Nice new fork:

My use of 15mm stubs were limited to this axle so with modification from flange fit to tube fit also goes to a new home:

Rubberly

Kenda's are fitted to the rear and the front needs a little modification to fit such fat wheels as these.


Then I realised how many wheels I have... have tested over the years. Here's an idea...

Running in

I've spent over a week working late winter nights to get it running for the midwinter BBBB event. You know you've been rushed as you do your final assembly and first sit in the buggy on the beach.

Springboard axle was a surprising success. Running over washboard ruts on the beach I soon realised that I was hearing the wheels on the ruts and not feeling them. Normally hard turns would break traction early in these conditions. With no axle tramp and reduced wheel bounce I had a hard time sliding this buggy.

Footrest came out nice but very heavy. I'll build another lighter set. However the weight balance was spot on the few times I got to break the wheels loose in a slide. Do need to trim the mudflap though.



Things to finish:
Shorten the stirrups
Trim the mudflap
Replace the velcro on the seatbelt quick release
Finish the GPS mount on the goose neck
Replace the elastomers with an unpigmented set
Clean up all the final details

The new axle is complete including the frame to mount it. I like the way the angle work and complete the stubby back end of the seatframe. The finish is not bad for an atmospheric layup either.

Layup consists of:
2x layers of blue cotton
2x layers of 6oz glass
4x layers of 9oz chopstrand glass

The reason for for the chopstrand mat is to provide the strength in flex to absorb bounds without reflex as rebound would break traction




Here are some shots of the stub-axle mounts. The big washer is just a spacer that sits on the machined bearing journal to allow me to snug everything appropriately.



I plan to do one for the race buggy on the vacuum table next. I'll cast some sidewalls to protect the wood from moisture too. The flex worked out well and I just have minimal sag with my weight in the buggy. Jumping on the back axle with the wheels on proved that it was both strong and did not bottom out on the ground which is a good sign.

Carbon illness

Another buggier wanting to get into freestyling. This builder has patternmaking skills in a composite boat building workshop though need the metal parts for the divinycell core carbon frame.

His frame consists of a semi-teardrop shape profile and the headset is a mating fit over it.


To keep weight down we considered 20mm thickwall tube for the stubs and front axle. You can also see the head set abgle had to be adjust to get the right lead angle on the fork since the down tube section of the carbon frame was to shallow.

Chasing the rainbow

Managed to find a replacement pressure cooker for the one I used to use for degassing resins and fillers. However still have not resolved the curing issues when adding pigments and I'm still chasing down a source for powder acrylic pigment.

The brown elastomers are the natural unpigmented colour. The grey ones are just dirty from living on the workbench for a few weeks. These were donated to Peter Lynn's Craig Hanson as test samples.



Soon as time permits I'll hook up the vacuum chamber and mill some new molds to improve ease of demolding.

Straight to plan B

Seeing as my buggy still has no rear end I've decided to go straight to finishing a springboard axle.


I wanted to make a composite anti-sway bar for the leading link so it seemed like a good time to dive in and finish that too. While it's curing I started making the stub axles and frame to hold it.

Damp and squishy

The original idea for a rear damper was to build an elastomer torsion suspension unit. The concept consists of two sections of square tubing, one inside the other, with an elastomer filling the corners providing resistance to torsion:


The original prototype worked well with only 30° of preload required for my weight. After several hours of work on the 'production' model I was disappointed to learn that the rubber inserts I used were too soft and getting 60° of travel for preload.


This won't be suitable and I'll have to consider finding an alternative rubber or filling them with urethane in future.

Cast off

Wayne Carkeeks' leading link fork design requires the use of 60 shore hardness elastomer donuts to support two short swingarms holding the front axle. These can be had from Mackay Rubber at about NZ$75 a unit which works out to NZ$150 per fork. I found a source for the 2 part casting urethane with a similar hardness. At around $100 for 1.5kg of urethane I can cast about 10 sets. Leaving me needing some time on the machinery to make some molds.



The first molds were solid blocks of aluminium(square mold on the right) milled out to the dimensions with caps and relief holes for overcast. The elastomers proved just hard enough to demold that this was not suitable though the first set came out very nice. For the next molds I went three part and made 4 in total so I can cast a set at a time. I used blue acrylic tint for the first set as used for colouring epoxy which worked well. Though the second set I used a grey tint provided by the supplier. These did not cure nicely and will need to be redone. I'll stick with acrylic tints I know too.

Leading link fork... hot off the welders bench

In staying with the through-tube design I decided to mix it up a little. Since I'm casting my own elastomers I don't mind integrating the stubs in my design. Smaller cheaper fasteners and less loose parts.

To give you an idea of size, fork is over 300mm or 1' wide and that is a 20mm bolt and 32mm through tubes. I've made another set of rocker arms for the axle mount. The first set did not finish as nice. I will use them on the race buggy leading link fork.

Next to weld on some bolt tabs for footpegs and stirrups.

Just need braces

Differs from the original plan a little but the look now suits the rest of the build. Killed a 32mm TCT holesaw making the yokes for the forks and waiting on a delivery for a replacement. The only way to make big tidy holes in stainless quickly. Once I have the forks welded I can judge the seating position add the final bracing and start on the rest. Still a lot of cleanup to do but you get the idea:

Just struggled some big tyres onto the 11" asymmetrical rims. May just make it in time for the 4-5July buggy bash at Raglan.

Goose loose on the Moose

In order to match the size and add a bit of weight in the front I went with a Protask style gooseneck. Still have to clean a pickle it a bit after adding some tabs for the mudflap.


Original idea was to make a 'cubbyhole' recess to hold the GPS but it shielded the unit too much. Built a second with slightly less recess and have a block of PVC to make a holder out of using some acrylic for the face.


My visit to the recyclers proved fruitful and I could have spent a few hundred dollars on material. Got the flatbar I needed and stuck to my $40 limit. Today I did a little work on the seat frame and welded some gussets on the bolt tabs for the rear damper. Still pondering a yoke profile though I'm sorted on a way to match the rest of the design.

Evolutionary progress

1998 - Bit more padding and bigger wheels
This was the year PL introduced the midi wheel. The first shipment was sold before I'd even heard of them. In the mean time I found these 15" midi's which was a great upgrade from the 12" barrows. Decided to build a new frame, adding lenght and width. By this time I had also sourced a better sewing machine for building foils which came in handy for making buggy seats, foot straps and padding.


2002 - Bigfoots, higher rails and goosenecks
Finally scored a set of PL Bigfoot classics and built a buggy to suit them. First use of a gooseneck downtube. The picture shows the PL fork that has since been replaced and the 1" tube siderails has also been braced to cope with riding dunes.


2003 - The dark side prior to the hiatus
After failing to teach my wife to buggy I built her this small landyacht and while she still does not grasp basic sailing it's near impossible not to have fun with it.


Finally built a race buggy using 1.25" tubing, 25mm stub axles and a gooseneck downtube. By this time there was less than a handfull of buggiers in Auckland and no regular following.

New found inspiration.

13 years after taking up kiting I found my passion for buggying has waned a little. The freedom of the sea and watersports has always been more attractive. However buggying has always satisfied a more technical aspect for me. While I used to build a kitesurf board now and then it never involved the joy of machining and welding up a steel buggy frame.

Now I finally find myself with a TIG welder, lathe, mill and more importantly, enough room to work. So when a group of locals set off to challenge 100kph speeds it ignited a spark. To celebrate my new found passion I set off designing something new to build a buggy the way I want to build it.

Criteria:
Bigfoot wheels - choice of Duro's on 7" or 11" assymetric hubs
Leading link front fork
Chunky gooseneck downtube - parallel rectangular box section
Spaceframe seat/box frame - 1" tube with bracing and gooseneck socket, no flange clamps
Duratorq style dampener - multiposition end flanges allow some adjustment
Double tube axle with 25mm solid stub axles

Alternative to duratorq:
Springboard laminated back axle

Additional:
Built in GPS holder on gooseneck
Checkerplate alloy skidpan

Where it began.

1997 - Fabricating my first kitebuggy with little more than a hacksaw, handfiles, drill and a MMAW welder.


The 12" wheels were too small. The frame was too light. The steering was just a little better than a decade old shopping trolley.
But it was my first!