Second Thoughts on New Velo

I haven't done any more on the new velo just yet.  Some more thinking about how to proceed though.  Rather than build a one off velomobile from the plug I may just use the plug to create stations for a cedar strip velomobile.    The big advantage of using strips is that they tend to fair thenselves quite nicely.  This means you can get away with relatively few stations.   You would at a minimum need staions at the front and back of the front wheels, shoulders and the front and back ends.  One thing that would disappear is the two bumps for the knees and feet becoming just one ong bump.  It is tempting to just smooth out the front in one easy round shape but this makes the velo more suspectable to side winds.  The bumps actually help in cross winds by breaking up the airflow so you do not get pushed around as much.  It still happens but at higher speeds.

The primary reason to try this is out of curiosity to see what can be done. Cedar strip construction can be lighter than a fiberglass construction.  In some circumstances you can rival the performance of carbon fiber construction.  After all wood is a composite material that has been under development for millions of years.  Adding just a little glass and epoxy to both sides of the wood core adds some amazing properties with vey little weight gain.   I suspect that you could eliminate most of the wheel well structure commonly found in velomobiles and mount the front suspension struts to the shell.  You would still have to stiffen the shell in some areas to do this.   If it works out as well as I think it can I would consider offering plans or at least station patterns. 

This may well be a case to too many projects and not enough time.  What is most likely to happen is that I will work on the plug a bit more, stablize it with a layer of glass on the outside and then set it aside until I have time to come back to it. 

More on new velo

Here are a couple of pictures of the frame patterns I made of the first side to use as guides to make the other side the same.

When you take them off and transfer them to the other side you discovery that the sides are quite different.  It is quite easy to make the first side but matching the second side is always a lot more work.

Here is a bit more progress on the other side.  The front is starting to take shape.  It's hard to tell from the picture but there is a slight peak down the center of the nose that defines the shape quite nicely.  The bumps for the feet and the knees will cause lots of grief.  Getting them similar on both sides will be more work that the whole back end.  Anyway the usual thing has happened, I like the second side a bit better than the first.  This is particularly true in the shoulder area.  The area where it is the least defined is the door opening where I still have to figure how it will be done.  I am leaning towards having a fixed size opening without a door, just a foam lid like the Quest etc.  For access to the front chain ring I am considering a removeable hatch that is bolted in place.  You do need good access when assembling the velo but after that's done you rarely need to service this area. This will be particularly important if there are no footholes.   I don't like the head bump yet.  It ended up being a bit out of line as I just shaped it by eye without doing any measuring.  I will most likey cut it off and stick it back on measuring carefully this time. 

Just in case you are wondering why the second side is a different colour its because I ran out of the blue gelcoat which was custom colour match for a repair we did.  So I switched to a green we have and rarely use. 



Rear suspension and rear wheel size

There has been lots of discussion of rear suspension in velomobiles of late.  This has got me thinking about how I should setup the new velo with rear suspension.  For what I observed while riding the first few days of ROAM some improvement here is warranted.  This is especially true when crossing rumble strips here in North America.  I guess they don't have these cycling unfriendly things in Europe.  If they do they are probably a better design and  much less of the hazard. 

The first time I crossed a rumble strip was on the 200 km brevet.  I was approaching a bridge on the highway riding on the shoulder which was reasonable wide and clear of debris.  As the road neared a bridge it narrowed forcing me to cross the rumble strip.  As it was downhill I was moving at a good clip and just as I was going to cross traffic was approaching quickly.  I slowed a bit to ease in behind a car and  crossed without incident.  The rumble strip make a horrible noise as the front wheels crossed and the rear suspension worked well when it crossed.  I was more worried about merging with traffic than the rumble strip.   After this I didn't worry about crossing rumble strips until I read about trouble other folks were having with them.  On the second or third day of ROAM I saw Bram momentary loose control when he ran onto the rumble strip avoiding debris on the shoulder.  This was a particularly bad stretch for bits of wire and tire chunks on the shoulder which had me keeping my figures crossed that I didn't get a flat.  Anyway Bram regained control but he just touched the guard rail putting a mark on the side of his Mango.  There were a couple of other problems like this.  The heavier and more experienced riders didn't have any issues.  The velomobiles with two sided swing arms didn't seem to have trouble.  Now there are a couple of folks working on a better rear suspension strut.  From early reports the new suspension works well in improving handling.

I am thinking on doing it quite differently.  At present velomobiles have a strut goes from the swing arm up to a brace that goes from one side of the velo to the other.  This  stiffens the shell by linking the sides together and  attaches to the head bump.  I don't have this setup in the Borealis where the trike has the rear suspension built into the frame.  The suspension strut  (elastomer) is only about 10-15 cm above the floor of the velomobile.  I do have  "L" shaped bulkhead that extends up the sides to stiffen the shell.   Rather than use exactly this I am thinking of something that is more like the rear suspension on the Scorpion trike.  It uses a  common bike shock that is very adjustable for the rider's weight.  One advantage of doing it this way is you can build a very stiff floor to attach all this to. Combining this with the seat mount bonded to the floor on which you could stand anywhere and the potential for some weight saving  make this approach worth trying.

There may end up being two versions one with a 20" rear wheel and another with a 26".  I like the concept of only carrying one size of tube and tire especially for touring.  Beside with the smaller wheel there is more storage space.  All things being equal the  smaller size may weigh less.   I suspect that a majority of riders would prefer the larger wheel for its perceived advantages.

A bit more on the new Velo



Did a bit more on the new velo while waiting for some electrical work to be done in the new shop.  At first I though it was looking quite big until I lifted it off the sawhorses I had it sitting on and put it on the ground.  Once at ground level it was looking smaller than most velomobiles.   The amount of ground clearance at the front is actually larger than it looks as the shop floor slopes up to meet the doorway.   At the present size of the front with the bottom bracket at its present height there in no need for footholes or bumps to have heel clearance.  My shoe size is 44.   This way you can leave the bottom flat and very clean aerodynamically.   The bump behind the head is still too large and the shoulder width may be a bit excessive.  I will build the other side to match and then take a shape off the outside.  Once I have this layup done I can cut it into some parts so it will come off the pattern.  Then reassemble it and sit inside it to check out all the clearances.  

Yet more musing on new velomobile

I did a bit more on my mock up to figure out the smallest size I could make it to fit me.

Here you can see the seat angle which is now pretty much about normal for a velomobile.  Well maybe a bit less that normal.   My shoulders just fit under the curved wood strip which is about as low as you can make shell.  I will need to add bumps for my knees and feet.  The nose still needs lots of improvement  which will happen as it develops.  I thought of making a CAD model with the measurements from the mock up but decided against it.  I prefer working with the actual shape as you can see and feel the shape develop and make changes.  Sometimes the shape just doesn't look right so I like to let it sit and just contemplate how to make it right.  A comfortable chair can be a valuable design tool at this stage.  I will build the basic shape and then use some pour foam to further refine shape.  The not so fun part of doing it this way is that making the second side match the first is quite tedious and seems to take forever.  This is where the CAD and CNC model has an advantage.  You just mirror the first side and the CNC machining has them come out exactly the same.  Even when doing this I am always tempted to further refine the shape as the computer model never seems to be exactly what you intended.    Most of the material in the mock up so far is left overs from converting the barn into a workshop. 



A top view where you can see how much the wheels cant in.  It looks pretty skinny so far.  The challenge will be in making the wheel wells so there is an acceptably turning radius and just enough room so I just clear them without touching.  Some careful shaping of the wheel well around where the wheels go when turned should get the clearance I am looking for.  They will end up looking a bit different from what found in current velomobiles.  There is also the possibility of being able to build the velo with different amounts of ground clearance using the same mould.   Not entirely sure if this will work but it is worth a try.  With this idea in mind I have decreased ground clearance to 8-9 cm. 

More musing on new velomobile

I built a quick mockup of the new concept.  One thing that became obvious sitting on it and observing the space required for pedaling is that the derailleur post and front derailleur stick up into your sight line with the seat very reclined.

 In the picture you can sort of see the recline of the seat.  It's about what the ultra marathon riders are using for their seats and about the angle I need to be at to sort of fit in the WAW.  I'll also try it with the seat in a more upright position.   If you have bumps for your knees and feet vision to the front and sides can be quite good as most the shell would now be a few inches lower than normal.  One big disadvantage of this approch is that you may need a couple of sizes of tops for different sized folks.  I am not too worried about this as I am making it to fit me.  Making a different top would make sense if there was enough demand.
The sawhorses with the foam clamped to them were to check shoulder width.  It's now 51.5 cm which just fits me but I will make in a couple of cm wider so I don't touch all the time.   Right now my base pattern is a bit too short in the front to get a nice nose shape.  I may have to extend it 10-15 cm.  If I do this I will shorten the tail by the same amount so the total length stays at 280 cm.  Even with this change the back end will be very aerodynamic.  There may have to be a bit of a bump for my shoulders.   Maximum width on the base is 71 cm with a track width of 78 cm.  Next step will be to mock up the wheels and imagine what the shape may end up being. 

Thoughts on a new fast velomobile

The most sales of velombiles seem to be to folks who want to ride fast. This is not suprising as early adopters would mostly be serious cyclists and one of the primary reasons for considering a velomobile would be to go faster. What I am thinking of is something along the lines of a Milan/WAW/Evo K. It would have to have very good speed potential and still carry just enough gear to go touring. 

As for overall size it would similiar to the WAW.  With a shorter nose and a  longer pointer tail.  I would also have a bit more room for my feet, knees and shoulders. I am 6'2" and have size ten and half feet so I don't quite fit the WAW.  I could modify the WAW by putting in bumps for my knees and shoulders but it just seems wrong to do this to such a nice machine. Better that it eventually goes to some one who fits it properly. It should be possible to have a smaller frontal area than the Quest and still have enough room for gear.  From the bit I have ridden the WAW there is quite a bit to be said for its great cornering ability.  This comes about by its wider stance and front wheels that are canted in quite a bit.  Having you sit right on the floor helps too. 


It is very tempting to go with open wheel wells to decrease the turning raduis and make servicing the front wheels, brakes and suspension simplier.  Open wheel wells can be quite efficient provided that the wheels are nicely faired into the body with very little space around the tires.  The Evo K seems to verify that open wheel wells can be quite quick.  The best way to get this result may be to build the shell without the wheel wells and then glue them in afterwards.  Once the wheels are installed cut the opening to just fit around the tire. You could even adjust the size of the opening with an add on flat panel if you used bigger tires in winter and then switched to faster ones for summer time riding.  The big advantage is in how I would fabricate the bottom half as it is quite a simple part to vaccum bag or infuse without having to work around the wheel wells. Making the wheel well as a separate unit would also simplify making this part.  The risk of not having successful parts would be reduced. When you are vaccuum bagging or infusing you either get very good parts or junk you have to throw away.  What happens if you loose vaccuum at a critical point is  the part expands about 30% and fills with air.


My preference is for a head out velo but design it so a racing hood could be added for speed freaks.  I prefer the slightly bigger head opening so you can see inside the velo when riding with the roof on. The size I have on the Borealis seems about right.  This with a small foam cover for use in the most inclement conditions might be the best all round compromise.  The head  opening should be just large enough so you can crawl out of it if necessary. The size of the door section  should be large enough to make getting in and out easy.  Rather than go with a hinged door one that just lifts on and off is worth trying.  If it could just snap in place that may be ideal.  It should also sit on a substantial foam gasket so it doesn't rattle.  If it was just long enough so it could be made in different sizes depending on the height needed to clear your knees  you would have the option of customising the size of the velomobile a bit.  If you did the same with the section where your feet are with a removeable cover you would would gain easy access to the front derailleur, headlight and a bit more usefull storage space in front of the wheel wells.

Suspension on all three wheels.  While I would like to develop my concept for a carbon/basalt fiber spring front suspension it will most likey have the standard front suspension as found in other velos.  The time and effort to develop this is hard to justify when velomobiel.nl makes a very good unit.  Rear suspension should be an air shock  so the rider can personalize it to suit them.  The rear swing arm is best if not single sided so you have the option of using a Rohloff or rear hub motor.  Structurally  the double sided swing arm should be easier to implement.  If the rear swing arm can be pulled out of the bottom of the shell so changing the rear tire would be the same as on a normal trike.  One would have a removeable cover over this opening to clean up the air flow and keep everything clean. 

Ground clearance of around 10 to 12 cm.   Some cars are in this range for ground clearnace.  This will make it a very practical vehicle as it will handle most roads with ease.  Just the occassional speed bump that causes cars problems too may be an issue. 

Reverse gear would still be with at least one foot hole open. The mould would have  bumps for both feet so you then have the option of adding reverse or not.

Seat could be made easily removeable to make gear storage and cleaning the velombile easier.  If you can take the seat with you it would make the velmobile unrideable. 


This would be a monocoque structure with all the bike parts fitted to it.  There would be no separate frame except for the rear swing arm and a carbon front boom assembly.  Constuction would be out of kevlar and carbon fiber with some honeycomb or foam cores where necessary.  To get the most performance out of these materials the parts would be vacuum bagged or infused.  We have been looking into an epoxy resin system that seems safer to use than previous offerings.  It has very high elongation which would help to build a very tough shell.  There is a epoxy clear cost option that could add a very minimum of weight or even a paint that can be sprayed in the mould that would be lots lighter than gel coat.  In a few months there is an epoxy gelcoat coming from this manufacturer that can be bent into a one inch radius without cracking.  With any of these options spider cracks common in gel coat would no longer occur.   Target weight of less than 25 kg.  Cost is unknown at this point but it would be very competitve. Chances of this happening soon are quite low.