Tuesday, September 2, 2014

New Front Boom

Have been working on this since last year.  After a few false started we ended up with this.  I have the parts in the mould( the orange thing) for alignment purposes.

So far it seems to be stiffer than the aluminium boom it replaces.  The limitation for stiffness is the stiffness of the shell as the boom has to be attached to it.  Having the rather large "I" beam in the front of the wheel wells should really stiffen up the front end.  The really good part about this is we are saving around a pound.  The bad part is that it will cost more.

A close up of how you adjust the bottom bracket. There are to be four bolts that hold it in place.  One may get away with only using two saving a bit of weight.  Adjusting by two holes will most likely require changing the chain length as every two holes is two links.  The holes are spaced 1/2" apart.  Before coming up with this boom I tried wrapping a foam core with carbon.  That really got out of hand quickly as it ended up being a mess and went in the garbage.  Then I tried making the same thing in a mould but that got quite messy too.  The precision required to do it properly would require a CNC machined mould and a separate mould for the core.  I could infuse a top hat section in the mould and then fill it with foam.  This would take quite a while making it far too expensive.  After some calculations I determined that the carbon/foam one would only be 20g lighter than the wood core and carbon one.  I rather like using a bit of wood as it is nature's carbon fiber and can rival carbon when combined with composites and epoxy.  So what we have ended up with is a chunk of an expensive ski as the boom.     

I have had the bottom bracket shell in my GT creaking some.  After tightening the clamps a few times I finally took one out to see what was going on.  It would go away for some time after each tightening but would be there again after riding some tough hills. Here is a the first attempt at making a replacement and the used clamp.  Upon looking closely at the clamp it has started to bow on the vertical sides.  It was only applying pressure at the top and bottom corners.   I was using a torque wrench to get the bolts evenly tight and getting worried about snapping the clamp.  The first attempt at an improvement, while it works it wasn't easy to install as it has too many loose parts.

This is about version eight.  Only two parts with some flex in the corner.  I can't see why it shouldn't be an improvement unless the hose clamp isn't up to the job.  There are much stronger hose clamps than the ones I am trying out if these fail.

What it looks like installed on the boom.

Saturday, August 2, 2014

Up on two wheels/back on two wheels

I discovered that it is possible to get the Milan GT up on two wheels and recover.  It just kind of happened on a downhill section with an S curve.  I brake a bit before the corner and then just let it run but this time there was a car coming around the corner.  I was close to the center of the road trying to stay away from the crown of the road as it is going the wrong way.  When I saw the car I moved more into my lane and the inside wheel lifted.  I had a quick look around to where I might end up if it rolled and slid but with a small steering correction, all was good.  Where I would end up was in the trees beside the road after sliding on grass.  The velo would have been a mess.   How the rider would have fared isn't too nice to dwell on(probably OK but very pissed off).  Now that I have lifted a wheel on the road you can tell quite easily when you are getting close.  One can feel the inside wheel becoming unweighted so you know when it is time to back off.  I will take this corner a bit more slowly in the future as I must have been close to lifting a wheel before as the left wheel started to feel light.

Back on two wheels of a different sort.  There is more riding to do on the island off road than on, so I now have a new bike.  Never had a bike I could ride much off road before so it is a new experience.  I do need to learn some new skills as the last time I rode an upright bike for more than five minutes was over twenty years ago.   Already fell over twice as a result of a bit of overconfidence riding some easy trails.  More practice required.  The front shock is an entirely composite unit, seems to work quite well and is quite light.  Maybe the basic idea can be adapted to work in a velomobile.   I built a composite rear suspension in the Aurora which works great but is hard to adapt to a tadpole configuration.   Putting both ideas together and building a prototype to try it out may happen once I have some spare time.
Building the pattern(plug) to create removeable foot(heel)covers for the Milan SL.  I laid up some material to mimic the thickness of the foot hole covers and now need to make it all smooth and shiny.  If you remove the foot(heel) bumps from the SL you increase the ground clearance considerably.  I had to tie some kayaks on a new car the other day and ground clearance for the car was about the same as the SL with the heel bumps removed.  Considering that the wheel base of the car was longer the SL may have more clearance.  I noticed that on the front bumper of the car there is a rudder strip that hides the scrapes under the car's front. With the heel cutouts you also get reverse back without opening the door and using your hand on the ground.  This works for me but for shorter folks this may not be an option.  You also get more ventilation with air coming in the foot holes. 

Wednesday, June 25, 2014

Monocoque or Hybrid??

Here is a photo of the structural reinforcing bits that go into the Milan SL.

The wheel well is in velomobiles with enclosed front wheels.  The other ribs are sort of borrowed from boat building where stringer systems are quite common.  They are made from two layers of carbon with some extra reinforcing and then secondarily bonded into the shell.  I have thought of infusing the parts with foam ribs but by the time you add in the weight of the foam you are at about the same weight as the bagged parts and secondary bonding(hollow ribs).  I have a bit more freedom in shaping the ribs with my present method.  The long S shaped rib could be shorter but the added 70 g or so is a worthwhile addition in stiffening the panel. 

I finally brought my Garmin along on one of the Wednesday night rides.  The ride ended up being about 50 km long with about 700 meters of climbing with an average speed of 26 kph.  I am faster when there are other riders along it seems.  Riding by myself doing the same sort of ride would be 3-4 kph slower. The first and last 5 km are slower than the average as I ride to the start and then back home again.  One interesting thing I noted was that the velo climbs better than an upright bike if the grade is low enough.  I'll keep track of at what sort of grade and speed at which this happens.  If it gets too steep like about 5% or more the extra weight of the velomobile really shows up.   One of these weeks we will do the Wednesday night ride out of Campbell River.  I am looking forward to the flatter terrain and smoother payment.   

Friday, June 13, 2014

Miscellaneous Musings

First off a new rear cover for the rear wheel openings in the SL.  It took a while(three tries) to get it right. Delayed a couple of times by other stuff that needed doing but now we just need to sand and polish the modified part of the mould.

Hiding the tent away inside the GT or even the SL.  It fits very nicely in the turtledeck.  I stuffed the tent in separate from the fly but with a a bit more practice getting it all in would be pretty easy.  The poles and pegs fit up there too. What would work even better would be a new more compact tent.  New ones can be about half the volume.  Our tent is a good sized two person unit of an older vintage.

Tank vs central U-joint steering.  After having installed a few tank steering units in the GT and SL I can completely understand why, from a manufacturing perspective, central U-joint is the preferred system.  I have been trying to train myself to be good with either one but I just like the tank one better.  About 10-15 kph faster with the tank steering before things get uncomfortable.  I'll keep working on getting better with the central U-joint one.  The training process with the central U-joint has improved my steering with the other system.  Now I have to be more careful as it is too tempting to just let it run.  There are a few spots on the downhills here where you really should check your speed.   The rough road here encourages that anyway but you can still overdo it for the conditions.  I would much rather build new velos than fix built ones!!!  The one negative on the tank steering is that the levers take up some storage space.  In the picture you can see that it isn't all that much.  About a water bottle's worth of space but still with room for a bag beside the levers. What would be really handy is a foam shelf for small items just beside the levers.  It could be stuck on with Velcro so you can fine tune its location.

For the good, fast crowd, one could add a clear fairing to the back the the mirror fairing to clean up the aerodynamics around the mirrors.  A camera in the tail and screen would be even more aerodynamic but I really like the simplicity of mirrors even if they slow you down a bit.  I use them a lot and feel very uncomfortable without them.  Even having just one doesn't seem enough.  I would put having a mirror on each side onto the list of essential safety equipment.

Saturday, May 31, 2014

Best Ride Ever?

Well maybe not quite but certainly right up there.  There is a Wednesday night ride on the island here.  I have been taking part most weeks using the Milan SL, Milan GT  or my high racer.  Lately it has been the high racer but this week it was the Milan GT.  It ended up being a great choice for this ride for some not so obvious reasons.  The folks on the ride have been threatening to go north for some weeks now.  Going north is the most hilly and twisty paved road on the island and definitely the most velomobile unfriendly ride.  First one out onto the road decides where we will ride.  This week there was lots of milling around before someone finally turned left or right.  We turned right and then right again after the store so we were heading north.  The first kilometer was OK just some rolling terrain where I was out front but this wouldn't last much longer.   I was already braking a bit on some of the turns as I didn't know this section too well.  Several times the faster folks almost caught up but the terrain was just in my favor.  Then it started to go uphill and everyone passed me.  I almost caught up again but was reluctant to just let it run as the road was fairly twisty.  Time to just enjoy the ride and slowly pedal up the hills.  The sun was shining thorough the trees and it was a lovely evening.  Riding up wasn't so bad just take your time and look around.  I had only driven this section before and you don't see much at car speeds.  All the different greens at this time of year are remarkable if you only take the time and look.  After climbing the first big hill there is a very steep descent which had me on the brakes most of the time.  I was thinking that maybe I should just turn around and head back rather than have to climb back up this and more.   I kept going and met the group just after they left the turn around spot.  On the way back there were a couple of spots where it was impressively steep where forward speed was very low.  The group waited just before the last big descent and we all took off.  I was near the front and let the three or four fast guys go first.  I was on the brakes quite a bit.  Most impressed with how the GT handled the curves.  I could stay with upright bikes on the corners until I chickened out and braked.  No issues with braking at speed with tank steering as I had practiced at bit previously.  It was a good thing to have the tank steering as I was applying quite a bit of force at times.  So much braking that the next morning my hands were a bit stiff.  At the end there was a straight bit down and then up to a stop sign.  I couldn't resist finally shifting up to the big ring for the first time on the ride and going for it.  Short but quite fun to zoom by folks in their tuck like they were standing still.  Had to brake hard for the stop sign.

Monday, May 5, 2014

Topless Milan SL

While out for a quick spin my neighbour mentioned that I was riding topless.  At first I didn't think much of the comment but the next day after quite a few more short spins I got a chuckle out of it.   My short spins were rather short as I would only go to the nearest intersection where I could turn around.  I got rather good at using the crown of the road to roll backwards to make multi-point turns.

The reason for riding without the door on was that I was adjusting the the rear suspension and fine tuning the fit of the swing arm in the rear fender.  After a few attempts it is finally just right.  I may still adjust the length of the rear struts to slightly lower the back end of the SL.  The back end now a bit lower than before and we have gained a tiny bit of clearance at the front.

In the many times I had the rear wheel in and out and the velo upside down I took a good look and at the bottom.  The only bit that was scratched up was the scuff pads on the footbumps.  It seems that when the footbumps touch it slightly lifts the front of the shell as the front suspension allows this to happen.  One does still need to be aware of dips with slopes that go up just after the dip.  Mostly one can deal with these by taking them at an angle.   So far I haven't found the low ground clearance to be a real problem.  It's bit noisy at times scraping the protective skid pads but otherwise very manageable.  Yet another misconception that didn't come true.  The other two for the SL were getting me to fit for leg length and width between the wheel wells.  The distance between the wheel wells varies from 14.75 to 15.5" depending on where you measure but I still have clearance.  When I first mocked up the space it seemed awfully tight but it seems to work well for me.  The reason it works is that the narrowerest dimension is where your knees are and the widest where your calves or thighs would touch.  The more I learn about the design of the Milan the more impressed I am with the thoroughness of the designers.
 The scuff pads after riding for a while.  From looking at them they should last a long while.  The tape is so I can fill the little voids in the join line.  The gel coat fills will be sanded smooth once they are hard.  I'll also scrape off the silicone that has squeezed out from glueing the scuff pads on.

Thursday, April 24, 2014

Some news about the Milan SL

I have come up with a different way to hold the door in place on the SL.  I am using some shock cord to latch it at the front and back.  The previous method had a hinge at the front that seemed to rattle some at times.  It was also hard to remove and replace if you wanted to remove the door to work inside the velomobile.

The shock cord at the back edge hooks around a plastic hook bolted the the door.

The same idea at the front but I will be changing it slightly so its easier to reach.  This was the second attempt so the final result will be neater.

The additional advantage of being able to prop the front edge open for ventilation or for use as an air brake for long descents. You would most likely had to have it open more for much braking effect.  It just a rocket going down hill. 

I went for a ride this evening checking out the local time trial course.  I did ride a time trial on it yesterday so had another go at a slightly slower pace to figure out where to optimize my effort.  On yesterday's ride I got it slightly wrong in not attacking a slight grade enough and lost some speed. Even though I had ridden this section quite a few times I didn't realize how much it could hold you up if you had your effort wrong.  I guess this is the difference between racing and just riding.  The slower ride was about 30 seconds longer than the actual time trial.  During the time trial I had a few folks in front of me to catch so the rabbit effect was in full force.  I did the course in 9:47 with an average speed of 44.27 kph. The course is a bit hilly and not much in the way of rolling hills that favor a velo.   Right now I have a rather low high gear in the SL mostly so I also have a very low gear for climbing the hills here.  A bit higher gearing would have helped some but the engine needs to be more fit to make a real difference.  It wasn't too big of a surprise to set a new course record considering the aerodynamic advantage of the SL.

I am getting using to the tiller setup in the SL.  I was a bit shocked to see a max speed over 83 kph as I braked  some to keep my speed down.  I will continue to ride the SL and then switch back to the GT once I have changed out the rear fender.  The new three layer fender with carbon and Bio-Mid is much less noisy than the glass and Kevlar one.  They both ended up weighing about the same but the carbon/Bio-Mid one  is much nicer and will even go into the glass versions of the Milan.  One does get spoiled easily.  

An Xseam of 45" or more means you will not fit in the SL.  With very short cranks and an extended BB position it may be possible to fit slightly taller but I would recommend a trial fit.