Cycling: Why Tunnels are Better than Bridges

September 11, 2014 by kris de decker Filed Under: Bicycles, Bikes, Pedal power, Random, Roads, Travel
  • Tunnels offer faster journeys than bridges due to less climbing. Steeper gradients can be used than with a bridge because cyclists going into a tunnel first ride downhill and pick up speed which can be used to climb back out of the tunnel.
  • Tunnels have a smaller height difference than bridges. Only need clearance for the height of a cyclist, not for trucks or trains plus electric lines.
  • Tunnels take up less space than a bridge because inclines are shorter.
  • Tunnels are easier to fit into an existing landscape.
  • Tunnels offer protection from wind and rain.
  • A possible disadvantage is low social safety. It is important that cyclists can see out of a tunnel before they enter it. There should be no turns within the tunnel, no-where for a potential mugger to hide. Obviously tunnels should also be well lit.

why tunnels are better than bridges

Picture: All crossings in Assen [The Netherlands] can be used without slowing down. This is one of the many cycle and pedestrian crossings of a major road. Four metre wide cycle-path, separate pedestrian path, gentle inclines, well lit and we can see right through for good social safety. Built in the 1970s, well maintained: last resurfaced 2012.

Quoted from a blogpost at “A view from the cyclepath”, which discusses Dutch standards for cycling tunnels and bridges.

Eight-Wheeler Cargo Cycle

April 28, 2014 by kris de decker Filed Under: Bicycles, Bikes, Cargo, Cargo cycles, Pedal power, Quadricycles, Random, Recumbent tricycles, Travel

8wheeler cargo bikeThink you need a car or a van to move large and heavy stuff around? Think again. This eight-wheeler cargo cycle features a 10 m2 bamboo loading platform and a 450 kg loading capacity. The chassis is based on that of a concrete mixer. The vehicle has four-wheel steering and independent wheel suspension. With two drivers it achieves an average speed of 10 – 15 km/h, which could be further increased by the use of electric motors.

The cargo cycle was designed and built by Berliner Nico Jungel. Find more pictures and videos at his website. The vehicle was spotted at the International Cargo Bike Festival in Nijmegen, the Netherlands. See all pictures of the event (including more images of the 8-wheeler). Previously: Cargo cyclists replace truck drivers on European city streets.

Foot Powered Sieve and Bandsaw

October 9, 2013 by kris de decker Filed Under: Human power, Pedal power, Pedal powered machines, Sawing machines

The Archanes Project, a natural building collective from Greece, shows two interesting designs for foot-powered machines: a sieve and a bandsaw. 

“When George Chiletzakis told us that he wants to make a bandsaw, that will operate without electric power, at the beginning we all laughed. It seemed that this gave him bigger strength and inspiration to show us that he who laughs last, laughs best.”

Bike-Powered Treehouse Elevator

September 20, 2013 by kris de decker Filed Under: Pedal power, Pedal powered machines, Random

bike-powered-treehouse-elevator

Ethan Schlussler of Sandpoint, Idaho, built this clever bicycle-powered treehouse elevator to make it easier to reach his nearly 30-foot-high treehouse. “I got tired of climbing a ladder six and a half million times a day, so I made a bicycle powered elevator to solve this problem,” he writes. See and read more at Make. More pedal powered machines.

Ride Your Bike Faster or With Less Effort Using a Partial Fairing

April 3, 2013 by kris de decker Filed Under: Bicycles, Bikes, Pedal power, Random

The rolling friction of the tyres is the main resistance acting on a bicycle at speeds below 10 km/h (6 mph). At higher speeds, air resistance becomes far more important. It accounts for more than 80 percent of the total force acting to slow the vehicle at a speed of 35 km/h (22 mph). At this speed, it would take a power output of 345 watts just to overcome air drag when riding an upright commuting bike (on a level road in calm conditions). Riding a velomobile (a recumbent cycle with a fairing) can lower air resistance dramatically, reducing power to overcome drag to about 30 watts at a speed of 35 km/h.

bicycle with partial fairingHowever, velomobiles are expensive. A much cheaper option is the use of a partial fairing. These wind screens, made of shatter resistant polycarbonate plastic, are mounted at the handlebars. A partial fairing is placed so that the rider is able to see over it, not through it. Apart from reducing air resistance, it is also an effective shield against bugs, rain, cold air, and road debris.

Partial fairings are available for different types of upright bicycles, and for recumbents. They weigh between 600 grams and 1.5 kg, depending on the model, including mounts. These accessoiries, which can often be seen on motorcycles, are relatively unknown to cyclists, mainly because they are outlawed in conventional bicycle racing.

When used in combination with a road bike in touring position (with the hands on the handlebar), a partial fairing brings the power required to overcome air resistance at 35 km/h down to 157 watts. This compares to 220 watts for an unfaired road bike in touring position, and to 176 watts for an unfaired road bike in (a much less comfortable) crouched position and wearing tight clothing. A partial fairing on a road bike thus offers a similar advantage to that of an unfaired recumbent (148 watts). With a headwind, the advantage of improved aerodynamics becomes even larger. One disadvantage of fairings is their sensitivity for crosswinds gusts. It takes some practice to get used to them.

The numbers above were taken from “Bicycling Science” (third edition), by David Gordon Wilson, pp 188. The result for the partial fairing concerns an older model, so it might be an underestimation. Picture: a small partial fairing by Zzipper.

The Culticycle: a Pedal-Powered Tractor

February 13, 2013 by kris de decker Filed Under: Farming, Pedal power, Pedal powered machines, Random

the culticycle

“The Culticycle is a pedal powered tractor that can cultivate, seed, spray, or pull gear for most low horsepower tasks. Small tractors do many jobs very well and very fast, but also consume fuel, compact soil, cost a lot, and cause physical damage to the operator -– mainly spine and joint problems. Many of their jobs could be done, slower but better, by human pedal power.

This prototype consists of:

  • the front ends of 2 bikes welded together at 42” on center;
  • a lawn tractor differential mounted in a unistrut rectangle for a rear end , with 3/4″ round axles and 20” ATV tires;
  • a bike frame welded above the rear end with motorcycle sprocket and chain driving the differential (a springloaded idler tensions the chain);
  • a belly mount lift to hold cultivators, seeders, etc.;
  • a bike handlebar, separate from the bike frame and joined to the front end, steering the front wheels.

The materials are rebar, unistrut, landscape rake tines, and parts from bikes, an ATV, and a lawn tractor. It attempts to show that human pedal power can do some jobs of small tractors, albeit in twice the time, and that the design can be simple enough that no extra weight is needed for traction. The effort required is similar to climbing a 10 degree slope on a seventies Schwinn 3 speed. This prototype was built for testing: a more easily buildable version is in the works.”

Found at Farmhack. This is begging for an open modular approach. Thanks to Tim Cooke.

Read more: Slow Farming Tools.