Morning Light

The earth hurtles around the sun and on that journey it tilts. At the moment it is tilting in our favour making the days longer, the weather warmer and more light for our morning bike rides. In fact we are almost in shock at how different the bike rides look after months of darkness. It has even put us off riding, with the light showing roads that do not meet the expectations of our imagination. The legend of the hills ride that has grown out of many cold and dark days of riding, sweating, heavy breathing and burning legs. Maybe we need to start at 5am, maybe we just wait till daylight savings plunges us back into the dark ages.

Today we opted for mountain bikes (MTB's) up the hills. Alex had his road bike in for a service so I decided to, in sympathy, ride my MTB as well. Well half an MTB, I had slicks on. We thought that it would open up the field a little bit and bring us all onto a more level playing field. Well they don't call them mountain bikes for no reason and with the heightened expectations put up against us Alex and I took the early mountain points.

As we rolled into the sprint, every one held their cards close to their chest. We were in a square configuration, the 2 MTB's out front and the 2 roadies out back. There was some chit chat going on trying to hide the tension that was building up as every rider analysed their chances of taking out the sprint. I moved forward on the inside and Alex's tractor like hum started to move a little bit behind, I could see that he was not going to be too interested. Next thing, whoosh, Joel comes through between us and is off. I was anticipating this so I was quickly on his back wheel. Not sure who ended up winning but I was sure happy to have reacted that quickly to Joel's attack.

The final hill saw me with an early break due to a traffic light up Burgandy. I knew that the advantage was unfair so I took it easy waiting to be caught. Finally Alex got to me and went past, I pushed on the pedals to catch him. I looked up and for the first time in a while I saw my shadow, further up the hill, his shadow looking at my shadow looming. I tried to take advantage of the situation. I sat between Alex and the sun, in this way making my shadow merge into his and not give away my position. I pulled back a little, the idea was to change gears and power up and over Alex. Clunck, k-chunk, a bad gear change from me. Alex jumped out of his seat as if he saw a snake to another Cod d' Burgandy victory.

Discussion

Discussions turned to high performance power assisted bikes and compressed air horns on bikes with the compressed air being generated through some sort of pump whilst slowing the bike down a hill.

The idea of the performance power assisted bike is to be able to easily maintain a reasonable average on a road bike over a reasonable distance for commuting situations. For example, commuting along a flat road like Nepean Highway from Frankston (40km) may be a big ask to do on a daily basis even for a competent rider hovering around 33 km/h average. Add power assist that could bring the average up to 45 or 50 even 60km/h and it looks like an interesting thought. It seems that most of the power assist bikes are aimed at people who do not want to pedal at all and still travel at 25km/h. At the moment I can't seem to find a good discussion on the merits of this on the web. I would say it may be an easy calculation, good cyclist averaging 33 km/h on flat course gets a boost from 300W motor and some added weight for motor and batteries...

Ahh there was this, well it is not a power assisted racing bike but it shore did well in a race, up a volcano in Hawaii, Haleakala volcano, Maui. Read the story here http://www.solarnavigator.net/electric_cycles.htm. Then there is always the possibility in participating in the race, next year http://cycletothesun.net/

As for the siren, again there must be a simple equeation which binds the following constants together. It is just a question of filling in the gaps:

1. Horn to sound louder then a shout - ??? dB
2. Horn to sound for a reasonable duration between downhill recharges - 15 seconds
3. Compression required for air horn - ??? psi
4. Volume of compressed air to satisfy point 2 - ??? ml
5. Energy required to compress air for point 3 and 4 - ??? Watts
6. Is it reasonable to assume the energy for point 5 can be generated by a bike rider?

and then the equation to find the energy required (point 5) and compare this to point 6 to see if it is reasonable to produce whilst riding or rolling downhill.

[Power] W = [Compression] psi x [Volume] ml x [some other important factor]

Now an average rider can produce 200W or so, so the question is, is that enough to bring enough air to the correct pressure to sound a horn. Hmm will have to ride on that thought for a while more.

• Here is a pedal powered air compressor http://www.instructables.com/id/E5BEKH7O2SEP286E6D/, this one is a 2 horse power unit so not exactly portable. The idea makes it feasible. Just get a small electric compressor like used in cars for pumping up tires, modify it and feed it to a reservoir cylinder. Then attach an air horn to that cylinder.
• Here is an interesting patent, child playground to convert their play into electricity, using compressed air, http://www.freepatentsonline.com/7005757.html.
• Ok and here is someone who has almost done the same thing, well almost, but he has powered a coffee machine and a 12v chain saw http://www.los-gatos.ca.us/davidbu/pedgen.html http://www.los-gatos.ca.us/davidbu/pedgen/stats.html