Archive for the ‘Engineering’ Category

Bike – Getting the recumbent on the road

Monday, November 13th, 2006

photo of the recumbent bikeOn friday I talked to Colin about taking the recumbent out on the road to get a feel for it and make sure it still worked. He rang someone or other who did not sound keen, with distinct muttering of ‘public liability insurance’ audiable.

After a servicing, which consisted of adjusting all the brake pads and tension, fiddling with the derailurs, greasing up the chain guides, replacing a missing bolt in the left crank and putting some air in the tyres she was set for her first run.

Me and John wheeled her over to lakeside, and attempted to stay balanced on the bike. Going in a straight line was not too much of a problem, but turning was difficult as me knees were getting in the way of the above seat stearing.

Shot of me on a recumbent, showing how little clearance there is between the knees and the steering

I managed to get the hang of turning, and both me and John were surprised how fast it was. I was cycling along at a reasonable rate on the recumbent, and he was having to really put his foot down on his upright bike just to keep up. I would guess it is to do with the difference in frontal area. Take a look at this next shot.

comparison of the frontal area of an upright bike with a recumbent bike

All in all, it was a nice bike to ride although there were a few problems with it:

  • Knees got in the way of steering, making turning difficult. It also meant that you had to keep hold of the handlebars when cycling, as if you knock the bars when your knee is on the way past you would end up somewhere you didn’t want to be
  • The aluminium seat bars extended a bit too far forward, making it uncomfortable for me to sit with my legs on the floor. Somone with longer legs might not have that problem.
  • It was impossible to change gear because of the position of the gear levers – right between the legs, a long way from the hands.

Conclusion: I want one (I have added it to my wishlist!)

Bike – I spy a recumbent

Wednesday, November 8th, 2006

recumbent bikes in engineering storageOn Monday 30th October we went to see one of the guys in engineering, and he took us to see a couple of recumbent bikes that had been the subject of previous projects. They turned out to be two blue bikes – one seriously modified, and the other seemed fairly original.

Today we went to get the bike as we now had the relevant hardware to secure it in our newly allotted workspace. After setting up a backdrop and tripod, we took lots of photos of the bike, and of me on the bike with my feet in various positions.

film strip of me on a bike

When all the photos were layered, they made a nice picture showing the area that would need to be enclosed to allow room for feet.

Layered images showing the movement of feet on the bike

Bike – Project Plan

Friday, October 20th, 2006

Today we had the deadline for our project plans. I thought my was fairly good in the end – short and sweet, but it had everything it needed in it. In order for the accreditation of the degrees to work properly, me and John need to have distinct projects, or at least well defined roles within a joint project.

Risk AssessmentTherefore it has been decided for us to work separately up until our final design – then we will bring our ideas back together and build one design, hopefully encompassing good aspects of each design.

Today was also the deadline for the risk assessments for the project to be submitted. I submitted three: vdu safety, workshop hazards and prototype testing issues.

Bike – Preliminary Ideas

Tuesday, October 10th, 2006

Me and John sat down and discussed many of the ideas about bikes that we thought were interesting, some that were less interesting and some that were pretty wacky. Here I have explained a few of them.

a solar powered lightImproved Lights
We discussed making bike lights bigger, brighter, lighter in weight, an integral part of the bike, difficult to steal and easy to charge up. The legality of flashing lights was discussed, as was having two front and rear lights. Experiments could possibly be carried out to see what flashing pattern is most noticeable.

Photo of a bike with lots of locks on itIntegral Lock
These already exist in continental Europe as a bar that locks through the spokes, although we were thinking of a retractable cable.

Front wind shield/Exoskeleton
This could be tapered to improve aerodynamics, while providing protection from the wind and rain. This lends itself to being part of an exoskeleton. Colin Oram showed us drawings of a low, recumbent bike that was surrounded by an external “shell” and said this could be possible. The riding position could be fully or semi-recumbent which would provide more comfort and also aerodynamic benefits, although issues such as transmission and pedal location would need to be addressed. An exoskeleton would cushion the impact in a fall, and would prevent the rider from hitting the road at 20mph, causing skin damage. It could also provide protection from rain and spray. Front and back panniers could also be designed to take most of the initial impact in the event of the bike hitting the road, again protecting the rider.

Folding Handlebars/Moveable Bull Bars
These would make the bike thinner when transporting or storing it, while the moveable bull bars would enable a range of aerodynamic positions to be held. An experiment was carried out a few years ago on performance by a student who used a stationary bike on a turbo trainer, and fans to blow air at it.

Photo of some folding pedalsFolding Pedals
Again these would help to make a bike thinner when transporting it, but they could also be a safety feature in that if a cyclist is leaning over when going round a corner and the pedal hits the ground, it could “fold up”, thereby lessening the chance of the pedal digging into the ground and causing an accident.

Motor Assisted Bike
A motor could be mounted on the bike to provide power when cycling into a strong wind or up a hill.

Alternative to Chain and Derailleur
Gears within the hub could provide benefits to the rider, alternatively a continuously variable transmission could be designed.

concrete blockSolid Tyres
This would put an end to punctures, while still offering a comfortable ride, as foam technology is now very advanced.

Bike Covers
Easy-to-use bike covers would keep the bike (or more specifically, the saddle and handlebars) dry so that the rider would not get wet when getting on his or her bike.

Self-Balancing Bike
A bike that balanced itself without the need to put your foot down while stopped, for example at traffic lights, could be an excellent development, especially for a recumbent bike. Retractable stabilisers could be used for this, and they could help with pulling away as well, because balancing on a bike is most difficult at low speed.

icestormHydration Systems
A bottle with a drinks tube that was attached in position close to the rider’s mouth would make drinking on a bike much easier.

Folding Bike for Easy Transport or Storage
This would help to make it easier to get a bike on and off a train, for example. The handlebars and pedals could fold flat, making the bike very narrow, alternatively, the whole frame could be made to fold up.

Anti-Lock Brakes
On a wet road with wet tyres, or even on a dry day with sharp brakes, particularly with thin tyres, it is very easy to lock wheels and skid, which could be dangerous when approaching a junction. Anti-lock brakes would avoid this problem and enhance safety.

3rd Year Engineering Bike Project – Introduction

Friday, October 6th, 2006

Photos of a road in the Yorkshire DalesAs part of my third year engineering degree at Warwick Unversity I am completing a project to design a “Safe bicycle for British roads”. This will most probably take the form of a recumbent bicycle with an exoskeleton, but at the moment I do not want to rule anything out.

I am working on this with John Lenehan, who is also studying mechanical engineering at the University of Warwick, and at the moment we are unsure how the project will split nicely into two sections. I am sure as the project develops we will work this one out!
Photo of Tom cyclingThis section of my blog is meant to track my progress as I move through the different stages of this project, and provide an easily maintained platform for links to other sites, photos that I have taken and allow other people to voice their opinion by replying to posts.