Developmental Process

Critical criteria we wanted this vehicle to meet include:
  • a full, three-wheel suspension system for pleasurable handling and noise reduction (there is nothing worse than a VM that sounds like a wheelie bin!)
  • smooth streamlining - with a coefficient-of-drag (Cd) figure less than 0.12
  • total vehicle weight of less than 70 lbs (including either SRAM DualDrive or Rohloff SPEEDHUB)
  • quick-adjust for different leg lengths (must be just as easy as for a car)
  • a large X-seam range of 36" to 53" (using vertical wall measurements)
  • optional 'head inside' or 'head outside' fairing design
  • adjustable vents for riding in any conditions
  • large luggage capacity
  • reversing capability
  • wheels isolated from rider (to minimize muck and noise inside the vehicle)
  • mid-sized opening hatch (small enough to avoid risk of the wind catching it as it is opened, yet large enough to make for an easy entrance)
  • a wide gear range with disc brakes

We didn't feel we could satisfy these criteria with mere add-on's to existing products. It was time to look past previous achievements and make a dedicated velomobile (VM). In 2005 we started work on what we called the Quad, our full-suspension four-wheel disc-brake version of the velomobile. The Quad and its prior versions managed to get rid of the single main frame underneath the rider in favor of two side rails with the seat dropped down to the same level.

In 2006 colleague Michael Rogan realized some of his design ideas coming together while playing with his son's toy collection?and he and Paul Sims got straight into turning the concept into a full-size reality. The result? A space frame in which the frame resembles more of a box that the rider gets into, rather than sits on. Ian immediately saw the merits of it and declared the VM, alongside Anura, top priority for the company's R&D efforts.

The first full project utilizing this space-frame design also tested one of the aero shapes of the NACA (National Advisory Committee for Aeronautics). Although our tests revealed the NACA shape to be deficient in crosswinds, that name stuck and all space frames from that time onwards were referred to as NACA's in the Greenspeed factory. Needless to say we went back to the tear-drop design. The three-wheeler proved very close to the Quad in stability?and for much less weight, so we stuck with it.

Our next three versions of the NACA refined seating and steering mechanisms, saw a few braces added or lost. The final prototype inherits the full suspension, which has been thoroughly tested on the Quad and various other trikes from the MR Components workshop. Only minor refinements are required before the model is released in 2009.

This last prototype has a naked weight of 39.6 lbs, which we found impressive, considering the rigidity of the frame and the fact that this included the full suspension, Shimano 105-level components and a SRAM DualDrive. The weight with the fiberglass fairing on worked out at just shy of 80 lbs.

Toy VM

Michael Rogan's original space frame in the flesh. Sometimes having something concrete in your hands is far better for relating to ideas. At Greenspeed we are not afraid to go 'old school' to test our ideas. Both Ken and Barbie seemed impressed with the test ride.


Many fairing alterations and designs were cut on the Quad. Here it is with our version of economical wind-tunnel testing (taped on pieces of blue wool). Here we are, going for broke with every conceivable idea crammed into the one fairing. The Quad was finally retired from racing-- the fairing had apparently been ?cut and shut? one too many times and its other parts used for future projects.

'Flat Naca'

The first test of the space frame sees it circling the racing circuit wrapped up in corex. This particular exercise we dubbed ?flat naca?, a slang term for pushing a machine to go its fastest possible. The frame has undergone a few different body shapes since then.

Mini Naca

This third version of the space frame sports the quick-release mechanism at the top of the seat, as was originally tested on one of our joint effects with Barry Cox in the CTD racer. We later went on to use pins at the front of the seat but adapted the sliding mechanism in place of the upper quick release.

BUT what about the ride?