Friday, December 31, 2010

Brrrrr!!!

Ended up riding 45 km yesterday.  Mostly doing a couple of errands and going for dinner at a friends.  None of the rides were very long but I got cold feet anyway.  I had thought that it wasn't quite cold enough to put the over boots on so the first couple of trips were OK as my feet only got a bit chilled.  I had a lightweight toque on under my helmet and was happy and warm at -5C.  On the last ride home at night in must have been a bit cooler as half way home I put the over boots  and some lightweight gloves on.  My hands warmed up quite nicely but the over boots just only slowed the cooling of my feet.  I ride in road shoes with a thin foam insole I added to block up the vent hole in the bottom of the shoe.  This amount of foam isn't enough so I will be adding as much thickness as I can.  I have some 5mm foam that I will try to fit in the shoes.  If this doesn't work I can always resort to riding in warmer shoes and not clip in. 

Managed to end up riding 6,000 km in the velomobile this year.  This is a considerably lower number than what I had thought I would end up at for the year.  At the beginning of August it looked like I would end with about 10,000 but that never happened. 

Tuesday, December 28, 2010

Rear Derailleur Sheild

This is still a bit of a work in progress but it is now 90% done.  Just another modification and I will be happy with it.  
 
The numbers on the part should help in adding the little flange to the part so the cover sticks out over the chain mid way along the swing arm. The chain is pretty much covered by the swing arm here anyway but adding the flange will make it a bit more so.  Once this is done the only bit of the chain exposed will be from the lower jockey wheel to the chain tube.  I am still thinking about how to cover this but its a bit difficult to do if you leave the rear wheel well open at the bottom so its easy to change the rear wheel.  If we were using a 26" rear wheel the derailleur would be much higher off the ground and this would be simplier to do. 

Sunday, December 26, 2010

The New Steering Arm

We have been working of the new steering arm for the Borealis for a while.  It will allow us to implement the central steering using the existing bearings on the trike.  The way we had done this previously was to use much smaller bearings and a sleeve that clamped around them which also stuck up far enough so the mast pivot could also be fastened.  Here is a picture of the first batch being made.  The mast pivot and the steering arm are now one part.  A much more elegant solution.
Along with the steering arm we have developed a carbon fiber mast and handlebar.  The first one should be assembled in a couple of days.  Once its together I'll post a couple of pictures. 

Monday, December 20, 2010

Heat Forming Foam

Did some more experimenting on closing off the wheel wells.  At first I tried just using a flat sheet of foam, bending it, making slots for the handle bar and tie rod to go through and holding it in place with Velcro.  The slots for the tie rod and handle bar are smaller in area than the holes normally found in velomobiles for the tie rods to pass through.  Should be quite effective in keeping the water out.  While this worked well it didn't look much better than the cloth covers we have been using.  I ended up with a pucker in the back corner under the shifter.  So I tried heating the foam and holding it in the wheel well of the Sprint plug.   This got rid of the pucker and shows lots of promise as a good solution.  The foam  shaped quite easily but you would need matched moulds to do it properly.   Luckily the shape is fairly simple so it might be possible to do this.   Some fabric glued to the foam would spruce up its appearance.   These covers would be similar to the cockpit covers on the Quest and Mango velomobiles.   The next step will be to make a mould  to help shape the foam.

Saturday, December 18, 2010

Riding in the Rain

Rode home in the dark today while it was raining.  It was a very pleasant time all things considered.  It wasn't raining very hard and I arrived at home without any water spots on my glasses .  I have been experimenting with the size of the wheel well opening to allow clearance for the handlebar and your hand with the original under the seat steering setup.  I bolted in a part off the mould that closed this area in completely and then slowly removed material until I have the minimum sized opening.  The reduction in the opening is about 50%.  I closed off part the the remaining area with some thin foam that flexes out of the way when your hand or the handlebar intrudes on it.  I also removed the fender as with a good cover over the remaining opening it should not longer be necessary.  Not having completely closed off the remaining area some spray still made it inside  but about half way home the potential solution suddenly presented itself.  I had been thinking of a cloth cover but that looked like it would be complex to make the pattern for.  It would need some stiffeners or battens added to the fabric to keep it from getting too close to the wheel.  An overly complex solution to a simple problem.  I will try the new idea out with some scrap foam we get when we order foam blanks for our kayak seats.  The scrap is the skins cut off the foam buns to get it to the thickness we use.  It is sent along with the foam to protect but I suspect it is mostly packed with it so the supplier doesn't have the throw it out.  We use it  to pack our kayaks for shipment.  Now it has a new use. 

Wednesday, December 15, 2010

Flevobike roof vs My roof

Here's a picture I have been meaning to take for a while.  It is the Flevobike roof sitting on top of my roof for comparison purposes. 
If you look closely you can see the attachments points bolted onto my velo for  the Flevobike roof.  So as a true comparison the Flevobike roof should move forward  couple of cm.  Until I put the Flevobike roof on top of mine I didn't quite realise how much longer mine was.  The big advantage of the Flevobike roof is that you can take it apart an stow it inside the velomobile.  Mine is more effective in keeping the rain out but you either have it on or its at home. 

It is the rainy season here now and I have my roof on almost all the time.  I much prefer riding without it as you are more connected with what's around you.  With it on it feels more car like.  The advantage of either roof is that with it on you are more anonymous.  Sometimes you just do not want the attention you get and the roof helps with that. 

Friday, December 10, 2010

Steering Arm

To implement the central steering we are making up a new steering arm.  I am having it CNC machined to fit on the existing bearings the Sprint come with.  It is taking some time to get it right.  Here is a picture of  the first prototype partially machined.  The roughing cut on the second side has been done. 

Thursday, December 9, 2010

New for Door for the Sprint
Have decided to add a small bump to the door so taller riders have more knee space.  I would just fit without the modification as its the same height as the Borealis V2.  I am 188 cm tall and have just 2-3mm clearance so added the bump will give me 10 mm or so.  Its not really fair calling it a bump as its the same height as the bumps running to the mirrors.  It does not change your vision to the side and still lets you see the road directly in front quite well.  One disadvantage of this change is that I will need to make a new mould for the wind deflector.   In the picture you can see one side has been done and I am now ready to start on the opposite side.   The first side is always quicker unless you have a hard time deciding on the shape.  Most of the work is in making the other side very similar to the first.  You can see a couple of lines drawn on the shape to help me in placing my profile gauge  when comparing the sides.  The other way we can make the model is to create it in the computer and then mirror it to get the second side.  You then have the model cut in foam on a CNC machine.  I have done this for some of my kayaks but the temptation to changes things a bit once you have the full size 3D model in front of you is sometimes great.   At least in this case yo are starting with two sides that are identical.

We have now built four of the five major moulds required for the new model.  The door is the last major mould.  It should be done next week if all goes well.  There are some other small moulds still needed but those can't be made until we have parts out of the ones we are working on now. 

Friday, December 3, 2010

More on Borealis for Sprint

The back top section mould about half done

The plug now only needs two more layers of mat to finish the layup of the mould.  Mat is randomly oriented glass fibers held together by a binder.  It is available in various weights depending on how much of it you want to use per layer.  We mostly use it for building moulds as there is no weave pattern to it that can print through to the mould surface. Its also the least expensive of the commonly available reinforcement materials.  It builds thickness quickly but isn't very strong for its weight as it is at least 50% resin.  The short glass fibers make it easy to get it to conform to shapes.  

The next step is to build the top front mould.  The pattern for the top front is almost ready for mould release.  Once this mould is done I can use the patterns for the back and front top to build the pattern for the door. 

One of the next posts will be about how my Borealis went on a diet and lost two and half pounds. 

Wednesday, December 1, 2010

More on the New Door

We have just opened the bag and poured the resin in.  We used about 1200 g of resin to make this part.  We could get away using a bit less next time maybe 1000g.  Of this amount not all ends up in the finished part as you need a bit extra to chase some air out of the part.  There is also some soaked up by the peel ply which gets pulled off the part after its hard.  The peel ply leaves a smooth surface and gets rid of bag lines.  Bag lines are those folds or wrinkles in the bag from getting it to conform to the shape of the part.  There also has to be extra to wet out past the  trim edge of the part.

Here we are part way through wetting the part out.  You can see the puddle of resin near the wetout line waiting for the vacuum to draw the resin into the dry fabric.  We use a Teflon squeegee to manipulate the resin by working on top of the bag.  The white plastic part in the bottom of the picture is the squeegee.  It has helped make thousands of parts. 
The bagged part completely wet out.  We now leave the part under vacuum until it has hardened.  The primary advantage of making parts this way is that the process is fairly clean and you are not in contact with the resin other than mixing it up and pouring in under the bag.  You can take your time positioning the material as there is not imposed time limit of the resin hardening on you.  The technical advantage is that the fiber content of the parts is much better than when doing a hand layup.  We get a fiber content of about 60-65% while with a well done hand layup you are about 45-50%.  The high fiber content gets you tougher parts at less weight.  The negative is that it sometimes takes longer to make the part and it costs more due the extra materials involved.