Light hybrid car transmission

Ultra-Light Hybrid

How far can a hybrid car be pared down to make the lightest, cheapest and simplest runabout?

Well, for a start the batteries should only be enough for the ‘key local services’ trip of under 25 miles; under 5kW.hrs then and under £1,000. And that immediately starts the benign circle of lightness where many components spiral down in weight and cost.

tiny car engine

cheap and light engine


The engine – This modified Honda GX270 engine can be picked up with one hand but still delivers 12hp, just like Fiat 500s and 2CVs of old. The engine connects to one end of a short power shaft via a lockable centrifugal clutch so the electric motor on the other end can start it.

The electric motor: Eg. The 7Kg Magnax motor is the size of a soup bowl and produces a peak boost power of 113hp. Our small batteries will considerably reduce this but even so the power will be adequate, especially if supercaps are used for acceleration. The motor also provides regenerative braking and two reverse gears.



hybrid car transmission

2 speed gearbox and differential unit

The transmission: From the power shaft two selectable gears drive the differential unit and the drive shafts. N.B. The gears can be replaced with chains and sprockets for a quick DIY version – just side plates without the cast housing.

Why two speeds? Some electric cars just have a single speed direct drive but having a low gear for hill starts and town pottering and a high gear for relaxed cruising is a necessary nod to the limitations of the petrol engine. A simple programmable logic controller matches gearchanges perfectly and more besides.

A cam driven pump on the drive shaft circulates transmission oil to cool the electric motor and the finned case dissipates heat from the returning oil without the need for a radiator.

With regenerative braking there is less cooling needed on the brake discs so they are moved inboard and neatly integrated onto the side plates. The petrol engine and the electric motor have to be spaced off to allow the brake discs to fit beneath them. The effects of this position change to inboard brakes are so profound that brakes are dealt with in more detail later.

The unit is completed by supporting the steering rack and some suspension as well. Super light vehicles need less unsprung weight; this solution is much better than in-wheel motors and brakes.

This tiny integrated unit is all there is to the powertrain. No wonder Silicon Valley, Dyson et al feel they can join the automotive fray – they can. When contracted out a package like this covers most of the engineering work leaving the new entrants to focus on their metier – control and electronic interfaces. Will car buyers want inexpensive light hybrids that run almost free and barely need a service? Maybe, but it’s the new breed of car makers that will first be attracted to this package.

Solar panels – Our low voltage batteries would be compatible with on-car solar panels. Between 200 – 400W trickling in all day is worth something like another 10 miles in the bank which is a huge increase on the standard range. This is only viable on light and low powered cars but makes for good marketing USP.

charging post for electric car

self docking car charger

Auto connect charging – Low voltage and low power enables safe charging like this. Drive up against the spring loaded prongs and the electronics check connections and allocate polarity. A vertical slatted grill on the car completes the connections but still allows air flow. No special accuracy is needed from the driver with last contact automatically controlled; just drive into your car port and press the ‘dock and charge’ button to let the car creep up and connect. An air blast dryer might be needed for wet days – hello Dyson.


complex panels made easy

Aluminium panels – Complex light panels can be made with a CNC machined ply and aluminium sandwich. Internal plugs with star washers feed heavy loads into the structure. Suitable for complex bulkheads, doors and in particular for battery boxes. Edges are peened over and ply machined away to leave hidden internal struts. Early Lotus F1 cars used a similar idea for bulkheads.



tube and mount for torsional rigidity

light but rigid bulkhead connectors

Light aluminium tubes between bulkheads give useful channels and torsional rigidity to the vehicle. The cast aluminium brackets have a slight internal taper at the ends. Tubes are glued then expanded a few thou with a pressed-in taper ring. For production it would be quicker and cheaper to swage (whack em with a hammer) the ends of the tubes.




The day that cars were required to do an emergency stop with no help from our leg muscles was the day hydraulic brakes became redundant. Instead of using ever more complex interfaces with electronics the hydraulics should have been entirely binned.

With inboard brakes it is easier to go all electric with no particular size restraints. For example a 120mm diameter stepper motor driving an internal ball screw could easily push a brake pad onto a floating brake disc. With each twist caliper’ mounted on a pivot, a load sensor can enable braking power to be calculated making these brakes particularly suited to autonomy. Actually, even calipers might be redundant; something more like a clutch assembly allows spring assistance (and a power free parking brake) and less power from the actuator. In other words the brakes are already on by default -like a clutch – and the actuator starts by forcing them off. Either way, all the usual features – EBS, ABS, yaw control, hill descent, handbrake, pad wear check, regen prioritising, LSD – are all easily accommodated.

I write this in frustration at the lack of affordable electric runabouts – likes and comments are welcome.



Amazing AirBnb driveable house

It’s a house Jim but not as we know it

Planners usually allow you to build a pod within the curtilage of your house. This one follows the rules but it comes on wheels. So what’s the point of that? Well for a start there are no foundations to worry about, just a bit of hardstanding will do. Then there is the ability to drive it; an all electric 4×4 chassis enables you to go for a trundle, down to the pond to watch the sunset for example. Steering is done from the front or from outside.

With the front wheels turned to full lock the whole house can rotate to track the sun, making full use of the 4.8kW photovoltaic array. So yes, it’s all off grid and only needs to dock occasionally to empty some tanks and to refill others.

Design – To make it all really feasible the design is based on off the shelf parts. So the house part is a modified 20′ shipping container supplied from a specialist constructor. The chassis part is from a 110″ Landrover with all the steering, gearbox and axles – a simple electric motor to drive it (cheap 240V, nothing fancy). Wheels are small and fat from a lawn tractor.

The solar panels are offset to make a canopy over the front porch.

Is it worth all the bother? Absolutely, for rental to eco enthusiasts this is a thrilling bit of kit. Imagine their delight when their pod comes round the corner to pick them up and take them to some lovely spot – all filmed from various points to give them a memento of an amazing experience. You can charge a lot more for that than if you were just offering a shed (I think they call them shepherd’s huts these days)….. is this a self powered off-grid shepherd’s hut then?

If you want to use this on your piece of land you might put a 3-point hitch on the back and call it a tractor – great to sit in a comfy chair while you mow the lawn!

N.B. With proper PV panel dimensions this is a preliminary sketch to see what it might look like.

Part of the drama is the house slowly turning to face the sun 🌻 a few times a day.

12 panels, 4.8kW makes another 14% through tracking the sun so it’s effectively a 5.5Kw array. Makes a useful UPS with it’s batteries. This machine will easily run your heat pump so it’s going to solve your heating problem too – at least an extra £1,000 in your pocket every year from that. Once hooked up to your main house the power can flow either way so the mini-split heater in the driveable house will always be useable, even after prolonged dark winter days.

So, £3,000 worth of electricity, £1,000 heating savings and over £1,000 a week on Airbnb + sales of the book and the experience video. Compare this with a buy to let house and with a build cost of circa £50,000 it doesn’t seem so mad after all. You could get your money back in 2 years and then live off this thing.
Guests are filmed as the house arrives, they get in and drive away to the viewing spot where there is a facilities block along with power and TV hook-up.
There’s a nice design for the hook-up to the facilities block. Ask me for details when you build this.


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Fan car – Ring record threat

There’s a good reason why fan cars have been banned in motorsport. Cars sucked to the ground will always produce astonishing cornering accelerating and braking performance but any disruption to the skirt contact with the ground – such as running over a kerb – is likely to see a very rapid accident under way. Of course, a car that literally scrapes along the ground can only be used on very smooth race tracks and would be impractical for the road. The engineers at Original Twist don’t entirely agree and think a new approach is called for. Here is the Original Twist fan car design. The usual idea is that flexible skirts on the car scrape along the ground to maintain a seal, the air pressure inside the skirt is reduced with a fan and the pressure differential forces the car down. The Original Twist idea deviates by separating the skirt from the car; an independent suction pad is held under the car and with its lightness and agility this pad is free to track the road contours even if the car is in more vigorous motion.

The suction pad is circular in order to keep the air bleeding edges to a minimum. A 60” diameter area with a 1 psi pressure drop will produce 2,800lbs of downforce; about the weight of a car then.

The suction pad is not directly attached to the car. Instead it rides on 4 small wheels like a circular go-kart which is towed under the car.

Fan car suction ring

Fan car suction ring

The skirt edge is held very slightly off the ground so there is no horrible scraping noise as you move along. The skirt is different too and employs hovercraft principles in reverse. Apart from the main extraction fan air is blown out of slots round the edge against the air that is trying to get in and that makes an inertial barrier. The blowing can be done with an extra fan in the nose of the car for example. The extractor fan probably won’t double up as the blower because the pressure/flow characteristics are different but it would be worth investigating. A concertina bellows connects the skirt edge to the underside of the car floor and the seal is complete. The skirt/kart is pressed lightly to the ground by the trailing links that locate it and although the relatively heavy car might be jumping and jiggling the skirt will tend to remain flat on the ground and unlikely to reveal a sudden and potentially deadly pressure change.

With an electrically driven fan the downforce on the car can be tightly regulated and as aero downforce comes with speed the fan speed can be decreased accordingly until eventually there is no need for it and the whole underkart can even be retracted. The retraction feature makes the fan car suitable for the road; a fan car that can cope with humps and farm tracks and then pop round the Nürburgring in 5 minutes has got to rewrite the book somewhat.

While all this is alluringly simple there is one complication. Cornering with 8 wheels instead of four is going to be out of this world but the kart wheels will need to be steered unless they are on castors. A supermarket trolley under the car won’t add much dynamically but a steered go kart, pushed down very slightly by the trailing arms, will make a major contribution to the cornering forces.

The potential for electric sports cars has been examined in

but the main point is that all the performance extremes of current supercars, in terms of acceleration, cornering and braking , can be exceeded by a factor of two or more. That means forces on your body, and head, of over 2g. It’s like doing press ups with someone sitting on your back so you’d need to be immensely strong to try the brakes without a full harness seat belt on. Cornering and braking at the same time would see you clawing your way out of the passenger footwell.

Formula One drivers experience forces like this but now a moderately priced sports car will be able to deliver the same. Headline figures of 0-60 in 1.5 seconds and 120mph in around 3 or 4 seconds will reset the performance bar in a shocking way. A 5 minute ring time is technically possible – just a question of who and when?

Note: Suck is a concept for when the force of atmospheric pressure – or other – acts against an object with lowered pressure on the opposite side. Really there is no such thing as a sucking force; when you ‘suck’ on a straw it is atmospheric pressure pushing your drink into your mouth.

With any fan car it is the weight of the atmosphere above the car which is pushing it down.

Atmospheric pressure is 14.7 psi at sea level so this sets the theoretical upper limits of our skirt with a total vacuum on one side. That would be about 18 tons in this case so the 1 psi pressure drop that equals the weight of the car is not too much to aim for and might easily be exceeded.

Solar tracking car charger garage

Sun tracker garage

Sun tracker garage

A garage with office space above is a common theme.  The Original Twist version goes a few steps further with up to 8kWp of solar panels which constantly face the sun as the whole garage slowly rotates. Photovoltaic arrays perform some 20% better if they track the sun so the 20 panels perform as well as 24 static ones. 4 extra panels would cost £1,000 so tracking is worthwhile banking well over 1,000 kW.hrs a year extra.

A conventional array would have problems with the varying inputs across the panels but here each panel has its own micro-inverter which also enhances reliability and the performance reporting via wi-fi is fabulous. Check out the Enphase web site for panels with built in micro-inverters.

The rotation does more than just sun tracking though.  With garage doors on both sides your car will be turned round and ready to be driven away again; a bonus feature where space is at a premium.

The height required by the PV panels gives room for a live/work space above. The space could be used as an office or even as an AirBnB pod with the added attraction of an ever changing view. Now the garage could not only power your house and charge your car but it could generate extra income in addition to the FITS return.

To get into the vibe lets have a look at a day in the life of the Original Twist rotary garage.  The car inside is a plug in E.V.  It can autonomously park itself in the garage and automatically connect up to recharge the batteries.  The garage rotates to track the sun, of course, but it also turns the car round ready to collect you from your front door all heated and fueled up.  A simple car that fuels itself automatically and completely free of charge is certainly compelling.  What future for smelly old petrol?

Everything we have talked about is available right now so this is only made futuristic by the novel assembly of concepts.  It’s certainly not too early to consider building your next garage on a turntable.

Vehicle to Home car chargers will be the next big thing. That fully charged EV in the garage will be powering your heat pump after the sun goes down. What started off as a car charging concept is morphing into a complete home energy solution.

…. and check out the LIST OF POSTS for more like this

Electric sports car 2020

EV Chassis

EV Chassis

Chuck a car out of the back of a Hercules and gravity will accelerate it to 60mph in under 3 seconds. Back on the ground it is no coincidence that a few supercars also accelerate this fast. They have enough power to give a push on the ground equal to their own weight; a similar scenario to the car falling out of the sky. Friction limitations of normal road tyres level the playing field for all these powerful cars but in the next 5 years there will be cheaper sports cars and hatchbacks that can perform better, and they will be electric. The 2016 Pikes Peak race was won convincingly by an electric car powered by six Yasa electric motors. Four of the motors used in the racer will do fine for an example of how our future car should perform. Allocating one to each wheel of a 3,000lb car means that it has to transmit 750lbs of shove on the road to push 750lbs weight to match the supercars. With a reduction gear of 2.8 the Yasa 400 motor has enough torque to do this and yet still not run out of revs before 190mph. For brief periods the maximum combined power of the motors is 880bhp so that should be erm, adequate if twice the power of a Porsche Turbo can be called adequate. In practice the acceleration should be better than anything on the road today because with each wheel finely controlled to prevent wheelspin the grip will be as good as it gets.
Individual wheel control will also transform road holding and handling. Imagine cornering with the outside wheels getting extra power and revs to augment the steering; worries about oversteer and understeer will be things of the past. In the same way that your satnav spookily shows the road ahead the on board computer can calculate the best power allocation to all the wheels to enable a safe trajectory through the bends and at speeds not really experienced in any car yet.

Pretty exciting stuff, but there’s more to come.

Of course if we could add enough downforce to effectively double the weight of the car (but not the mass) then it could go twice as well. 0-60 in 3 seconds becomes 0-120 in 3 seconds and back to a stop a neck wrenching 3 seconds after that. Cornering speed would depend more on courage and neck muscles than mechanical limitations. Sounds like fantasy land but actually it would be pretty easy to do this. Under the car a fan powered sucker pad, like an inside out hovercraft skirt, can easily develop sufficient downforce. The pad doesn’t actually touch the ground as small rubber wheels keep it a few thou clear. Obviously one wouldn’t drive around with the pad deployed all the time. It would be for track days or for seeing off the odd supercar at the lights.

Time for some maths.

A 60″ diameter pad has 2,827 square inches.  If the inside was a perfect vacuum the pad would hug the ground with over 18 tons (atmospheric pressure 14.7 psi). There would be heaps of torn up tarmac behind the car along with the odd flicked up manhole cover. Fortunately we just need a vacuum of a smidge over 1 psi to equal the weight of the car.  As I say – easy.

Regenerative electric braking relieves the mechanical brakes somewhat so with reduced cooling requirements the discs and calipers can be mounted inboard on the motor plates which in turn can also double as suspension mounts. The reduced unsprung weight will give superlative handling.

These power and suspension units can be deployed over a wide range of vehicles so, as I said, there is nothing particularly expensive here, in fact, quite the reverse. Anyone about to buy a £2m hypercar might like to pause for thought; the new era regular sports cars will soon leave it for dust.

For a more technical look at the suction pad look here

… and checkout the LIST OF POSTS before you go

Modern canal boat

click to enlarge

click to enlarge

Introducing the Original Twist canal going house boat; in the style of a narrow boat only bigger, better and absolutely modern. As a living unit it presents an economical lifestyle choice. For around £160,000 you get very low cost housing and maybe some change left over for a holiday house, long ski breaks and other good things. A comparable land based house or flat would be twice the price because of the cost of land, a boat on the other hand effectively rents the river via the canal licence and avoids council tax. This one avoids energy bills too which is a good start.

A house boat might be small but as well as reduced outgoings there are some great advantages. You are never stuck anywhere you don’t like; if you need a change you can just cruise to somewhere else, maybe near a cosy riverside pub. River life can be like an aquatic pub crawl but without the driving. You’ll make more friends among the friendly and hospitable canal community too, especially with the most interesting boat on the water.
There is more scope for travel than just the English waters as you can get a tow across the channel to use the huge French network extending all the way down to the South of France where winters are not so harsh. Otherwise the house boat is an attractive proposition for a house swap so the whole world is your lobster.
It’s a tough life being retired!

The Original Twist Eco-house boat is all about, modernity, comfort and enough economy to make a modest pension go far. Many traditional boat ideas have been updated to achieve this.

Unlike a go-anywhere narrow boat ours is 10 feet wide and 55 feet long – we’ll forgo visits to a few stretches of narrow canal in exchange for a lot more room and the garage – yes that’s right, a garage.
The shell of the boat is normal steel but without the enclosing steel roof parts. The front saloon and the rear transom are full height steel as is the central bulkhead that separates them. The two open parts between the steel constructions are connected at roof level by tubular trellised ladder frames which run the length of the boat interrupted only by the central bulkhead. The open parts of the boat are then covered by 2 insulated wooden rooms made of plywood and foam panels (SIPS).which are factory prefabricated – complete with windows, pipes, wires etc. This makes the boat lighter, cheaper and better insulated.

The two central living spaces house the kitchen a bedroom and shower room, all with heated floors. Each has a large pop-up roof (just like on a camper van) to give a more spacious feel while being flattened whenever a low bridge is encountered. These roofs carry the solar panels and can tilt sideways in either direction to catch the sun – the simple mechanism to switch hinge points is activated by the flick of a switch – an air cylinder shoves a cradle from side to side.
The steel and glass front saloon is very light and airy with a door giving access to the front deck. Standard fan-coil units are turned on end to make a pair of powerful demisters for the huge windscreen and to heat the room too.
A flat sun deck on the roof of the saloon makes a great place to watch the world go by and as we shall see later the boat can be steered from up there too.
The steel rear transom accommodates the propeller shaft, engine mounts, rudder mechanism, a niche for the air source heat pump.  A tail hoist mounted across the back (like on delivery trucks) supports a light vehicle such as a Polaris RAZR side by side.  After adjusting the height the ramps are dropped and locked onto a nearby bank so one can drive off in style and comfort. What is life without wheels?  Because the hoist can be folded up, the length of the whole boat can be shortened to navigate some of the tighter locks. An awning can be extended over the vehicle and there we have it; the first house boat with a garage.

The real point about eco-technomologicalness is to get along as cheaply as possible without damaging the planet. The 20 solar panels on the top produce a nominal 8kWp; a lot more than most domestic arrays and enough for the small air source heat pump and to charge the batteries for the electric hybrid drive system. The hybrid drive is almost identical to that on the Original Twist hybrid 3-wheeler found on this site; here with a Lynch motor and a Kohler water cooled diesel. The usual benefits of a hybrid drive are there; the batteries give a few hours silent cruising and the diesel can take over indefinitely. The batteries are mostly solar charged or sometimes diesel engine charged with the Lynch motor doubling as a generator. Many moorings supply electricity so the batteries can be charged on cloudy days. With the air source heat pump the heating will run cheaply and conveniently off connected electricity or the batteries.  So there are 3 sources of heating power; the PV panels, outside electricity and engine cooling . Most boat engines are cooled by river water but here a second coil in the heat bank uses the 60% of wasted heat to make hot water. There is no connection to the river or the gunk that blocks up the filters (boat owners nod knowingly here).
Heating is supplied by the little 2kW heat pump which delivers about 6kW. N.B. River water is not used as the heat source. See ‘Air source heat pumps in Southern Europe’ also on this web site. here
Notable omissions are a wood stove and any gas as there is no need for either. Cooking is all electric.

Control of all the lights, heating, entertainment and even the steering is done by i-pad and Z-Wave meshed radio modules which are cheap, reliable home automation items. Narrow boats are usually driven from the back, a bit like a bus driver standing on the rear bumper. We can sit at the front in the saloon and steer from there or from anywhere else within range of the wi-fi; perhaps the sun deck even from the nearby pub! The Z-Wave controller allows for plenty of home automation tweaks like lighting control, security and leak detection, all from anywhere in the world. Theoretically the boat can be driven from anywhere there is an internet connection.
Actuators to move things like the roof panels and the rudder are operated by compressed air which is cleaner and easier to maintain than hydraulics. An i-pad and Z-Wave relays makes child’s play of these things; even a simple dimmer switch allows proportional control of the rudder.  The motorised satellite dish also needs to fold into a recess in the centre section when a bridge is encountered.

Neat extras
To make the kitchen a great place for eating while admiring the view the picture window on one side tilts up and out and a table is pushed outwards to make use of the outside space. Once parked up an extending awning over a drop down side deck, complete with an extending Barbie unit, makes an outside cooking area.

Central dust extraction – The centre section houses a fixed dust extractor plumbed to outlets around the boat to make cleaning much easier.

With a boat like this life will certainly be rich and varied.

ECO-HIPPY – One who is sufficiently off-grid to live almost cost free.

More on this topic in LIST OF POSTS

Jumping motorised skateboard

Fast, light and jumpy

Fast, light and jumpy

Many versions of minimalist personal transport exist or have been proposed ranging from motorised skateboards to some excellent rubber tracked machines. To home in the best solution lets pose a question. Say you are a soldier about to leap out of a Hercules to a DZ 10km from your final destination. What would you like to strap on your back to make the mission go well, apart from lots of guns and ammo, hot coffee and a pocket full of Werther’s Originals? Most of the world is populated so there are likely to be some rudimentary roads and a few fields to cross so a folding electric bicycle would be a good start but could we get any better, smaller and lighter? Well there’s a problem; as a vehicle reduces in size from something one sits in to something one stands on the forces of acceleration or braking are trying to spin the rider about his centre of gravity and these can only be mitigated by lowering the C of G or lengthening the wheel base – think dragster – so that the forces are countered by trying to lift the load. This is pushing us towards something akin to a skateboard. Ah! Now there’s a twisty idea. A skateboard with a powered single enlarged rear wheel like the tail of a miniature motorbike. To counteract the back flip that acceleration would cause, the rear wheel pushes down to tip the rider upwards and forwards; a handy feature too when a small jump is required. Motorbike rear ends tend to squat under acceleration so the drive would incorporate an intermediate gear to reverse the torque and additional push would come from the dynamic electric shock absorber. Now a sharp twist of the throttle will result in an upward push from behind as well as a surge forwards.
The front end has 2 rugged 8” wheels that tilt and steer like the latest 3-wheel scooters but with a telescopic steering column that is good for the standing position or sitting when the seat is used.
The 15km range is every bit as good as an electric skate board and this can be extended a few times by a tiny 30cc petrol generator, about the size of the smallest chain saw, that can be clipped on just behind the front wheels.
So there you have it. A long distance 3-wheeler that you can wear like a rucksack, sit on, that can jump logs and ditches and needs minimal skill to ride. Now where’s my parachute?

Tyres: The springy rear end allows for solid rubber tyres all round. The ideal profile would be like an inverted ‘T’ with a raised rim around the circumference to give a smooth and economical ride and the side pieces with robust tread that only comes into play when the tyre sinks in mud or snow.

Honda GX200 in the Original Twist 3-wheeler

A 270cc engine in a car! Surely we jest?

Honda GX270 - even smaller without the tank

Honda GX270 – even smaller without the tank

Well first let’s see what the engine is required to do. Remember the car is a light, range extended plug-in electric car with everything minimalised to save weight. Even the electric range is cut back to 25 miles to halve the usual battery pack; half the weight and half the cost. In normal use the car would do the school run or a shopping trip on battery power alone but with no range anxiety thanks to petrol back up. Most electric cars boast longer range but for the majority of journeys they have carried around a heavy stack of surplus batteries. It follows that for most of our short journeys we are also lugging round the petrol engine so weight is going to be a major consideration.
The main use for the petrol engine might come from a weekend run in the country with some fast roads thrown in. With the 20-40bhp electric motor for brisk acceleration and overtaking the 12bhp petrol motor is really just for cruising at up to 50mph. Bear in mind that the engine is charging the batteries when the car is stationary, at the lights say, so the available, combined power when on the move is higher than one might imagine.
The Honda GX engine range actually gives us the choice to go for a bit more power but with weight penalties. Thanks to the go-kart scene they can all be tuned for more revs and more power. The rev limiter is always removed and a stronger flywheel added.
The GX200 only weighs 35lbs and can produce a useful 9bhp. The Loncin Chinese clone version only costs around £250 and makes a good starting point.
Next up is the GX270. Weighing in at 55lbs this might turn out to be the sweet spot between power and weight. With the usual modifications and the bigger carburettor from the GX390 this engine will give a good 12bhp.
The GX390 is good for up to 20 bhp but weighs a back straining 69lbs. Only testing will tell if that is departing too much from the light and minimalist idea but it would certainly be good for breaking the speed limit on the motorway. One should bear in mind that the engine and the electric motor are mounted just ahead of the rear wheel and the aim is to keep the overall weight distribution just slightly front heavy.
The engine mounting plate on the Original Twist hybrid 3-wheeler will be pre-drilled to mount all 3 engines so the choice is there. We can also consider the Briggs and Stratton racing engine with all the right bits built in at the factory – it’s called the ‘Animal’.
No doubt some inveterate tinkerers will have a spare engine for tuning experiments and, who knows, in time there might even be a racing series.
It is the intention that the engine will be pretty much clipped on and able to be changed in a couple of minutes so concepts like service exchange engines, rented engines etc are feasible. With that in mind the little 35lb GX200 that fits in a shopping bag looks attractive.

More on this topic in LIST OF POSTS

Hybrid 3-wheeler – structural panels

Eco-car structural bulkheads.

light and strong

light and strong


Aircraft grade birch plywood stuck onto an aluminium sheet has been CNC machined away to leave struts for load distribution and pockets for plug inserts. Loads are distributed by the remaining integral struts.



CNC machined panels

A mirror image version will then be glued on top –wood to wood- and the outside aluminium edges peened over to leave a solid looking panel (but largely hollow inside) which will not only look good with complex curves but be very strong and light. Any big holes in the panel will have the edges peened over too. Peening can be largely automated with a CNC guided rotating roller head.
Heavy loads from components bolted to the panel are fed in via plugs inserted into machined pockets so that any through bolts can’t crush the wood structure when tightened. The plugs are fitted in pairs with a larger star washer in between so that the sharp edges crush into the plywood to give even more load transmission.
Being CNC machined, identical complex panels can be produced quickly and with minimal labour cost. It pays dividends to design complexity out of the car and into the panels. Padded leather panels, a headrest for example, can easily be bolted up to the bulkhead as can other trim items.

Front and rear bulkheads in our car will be connected by 3 aluminium tubes. They will be joined to the bulkheads by cast ally brackets where the tube end is expanded and glued by a tapered collar pressed into each end.


The picture here shows how a side panel wraps the tube to make an immensely strong beam affording maximum side impact protection and, of course, a nice wide arm rest as well. The folding is achieved by machining ‘V’ grooves through the plywood leaving the aluminium skin to be a bent hinge line. A more complex shape to the groove can make rounder corners too.
The inspiration for much of this comes from two great car designers. Colin Chapman made racing car bulkheads from opposed metal sheets with peened holes and edges for rigidity. Alec Issigonis with his Morris Minor design used a complex bulkhead to mount suspension, shock absorbers, steering rack, battery box, pedals and more. We shall do the same.
No doubt the car will be strong, stiff and light but there is more to an eco-car than that; it must come at an affordable price and these techniques get us there all in one hit. In fact the car is so simple that anyone with a modest workshop and access to a CNC router could make one. Maybe a good base for a schools project?
Ultra strong and light complex panels like these will have many other uses. Paired frames for a motorcycle and a gyrocopter immediately spring to mind. In higher volume applications the plywood core can be precut with a waterjet cutter and then glued between the precut aluminium sheets.

More on this topic in LIST OF POSTS

Plug-OUT Hybrid car

Plug-in Hybrid? Yes but what about a Plug-OUT Hybrid?

The Original Twist Plug-in Hybrid featured on this site has some useful components in it which can be used for many other purposes:-

12bhp petrol motor
20bhp electric motor battery pack
Power shaft close to the rear luggage rack

We’re looking at such a hugely versatile mobile power house that it’s hard to imagine all the potential uses. I’ll leave that to you but here’s my first selection:-

Domestic UPS
A small inverter connected to the batteries will provide 240V a.c. which can power a house for hours. This feature will augment the battery pack that off-grid P.V. systems will have anyway.

Grid balancing
When electric cars go mainstream the grid will bid for their stored power via smart meters. A parallel hybrid will always be able to sell power when the price is right and still make the next journey.

Electric generator
The batteries can be kept topped up by the 9bhp petrol motor charging via the electric motor on the other end of the power shaft. Extended power cuts won’t be a problem.

Mobile power supply
The vehicle can deliver d.c. and a.c. power wherever it goes. The range of power tools that can be driven is endless and this will empower trades people and farmers alike.

Power shaft
It just takes an extra pulley on the power shaft to provide drive to anything bolted to the rear luggage rack. The picture here shows a compressor but it could be a lathe, a potters’ wheel, a wood chipper, a water pump ….. etc etc.
A rear p.t.o. is also easily arranged for light duty mowing, for example.

No problems with lighting and cooking when you go camping in a Plug-OUT Hybrid.

The Honda GX petrol motor takes just minutes to refit into a go-kart and it’s already modified with racing parts to suit.

If ever there was an automotive Swiss Army Knife this is it.

Swiss Army Knife?

Swiss Army Knife?

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