Dalinci Ducati FF under construction (LHS, 2020)
Proof that Eric Vloemans isn't just sketching FF designs! This photo was put up on his Dalinci website on 15th December 2020, reproduced here with his kind permission. It shows the front suspension, steering, and handlebar assembly of his Ducati-powered project. Eric explains:
"I’ve chosen the most complicated part of the vehicle to start the assembly process: the front suspension, and steering mechanism. The complexity is due to the many pivoting axes and moving parts. As can be seen on the photos, I’ve re-used quite some parts of the Ducati ST2 donor bike. The suspension and damping in the fork legs have been removed, and the fork legs are shortened to the minimum. A rear monoshock has been placed between the two front links (Hossack-type suspension). An additional link has been mounted on the top bridge, to connect the primary with the secondary steering head through a ‘Middleton link’, with two adjustable connection rods. Handlebar position is adjustable in height and length. Steering angle has been maximised and clearance between handlebar and upper legs has been checked. Tubes, plates and CNC-milled parts for the rear suspension and rear subframe are ordered and under construction.”
Photo: © Eric Vloemans 2020
More here: www.dalinci.be/feet-forward-motorcycle-design/561603_front-suspension-steering-and-handlebar-assembly
Norman Hossack's own Ducati!
Eric Vloemans and others might be interested to see how Norman Hossack himself changed a Ducati to his type of steering back in 2013. There's a lot of information, in both words and pictures, about it on his website, with the heading: The Bike Ducati Should Have Built. The first paragraph reads:
'After 23 years, Norman came out of hiding to make an already lightweight Ducati 800 30 pounds lighter, with the adoption of his HOSSACK suspension. Since racing a Ducati Mach 1 in the 1960s in Rhodesia, Norman a Ducati fan, always dreamed of making this bike.'
Lots more here: https://www.hossack-design.com/copy-of-the-ducati
A novelty!
Interesting to see how the geometric conflict between the suspension and steering systems has been accomodated - "The Middleton link", presumably some sort of rocking member? Not entirely clear from the photos and vapours. Easier for Norman on his Ducati because the steering is directly over the suspension, the rocking 'double wishbone' link is kinda standard in this application. I hope the Middleton link arrangement doesn't introduce too much stiction or free-play. More conventional set-ups, steering double wishbone suspension, just put the primary linkage in the same geometric relationship as the wishbones, and then link that to the secondary steering head (Banana et al). The Hossack system puts the steering system a bit high for the Voyager solution that uses a UJ and a single, torsionally stressed, shaft to connect to the steering yoke (AKA 'Handlebars), although I guess the steering drag links could come off the lower fork yoke to solve that). In later designs I eliminated the UJ and steering shaft and mounted the steering yoke directly on a transverse arm with drag links connecting to the suspension upright of a double wishbone HCS system (in the same geometric relationship). This surprisngly improved steering precision, pointing to the torsional flex in the steering shaft (25mm dia 2mm wall, seamless tube. 250mm long) and of course simplified and lightened the system.
Good to see metal being cut on another FF, even though it's got an air-cooled ICE. The claim that steering and front suspension are the most complicated parts may seem optimistic by the time aerodynamics and cockpit enviroment have been satisfactorily optimised. It only took ten years to get to the MK11 Voyager HCS, but I'm still chasing some cold draughts. Then there's battery packaging...
Good luck with this project.