Spitfire 26 Preview
I normally would not post a preview of a future product that is still in the development stage. However, I believe that potential customers can provide us with their ideas and suggestions before I start releasing these plans for sale. Therefore, if you have any comments concerning this design, I would like to hear from you. Please forward comments to Rickey Horwitz at firstname.lastname@example.org
The New Spitfire 26" frame accommodates both RS and ST configurations
In preserving a competitive edge, I have been hard at work designing my next generation of Spitfire trike. After much research and market analysis I have arrived at a new specification of product that I believe will continue my success of providing high performance recumbent trikes. Without further ado I introduce my next iteration of trike; the new Spitfire MkII 26. The narrow track Spitfire 26" now accommodates both RS and ST configurations. Consequently, the ST and RS designation now only represent the type of steering (either OSS or USS) and component groups. The major change with this design is the adaptation of a 26" rear wheel and a fixed seat position. Both of these key features represent a substantial cost savings. In addition to these features the changes are as follows:
26" rear wheel provides a higher gear inch range and gives a slightly smoother ride. The popularity of the 26" tire ensures that our customers can choose a wide variety of tires to suite their needs.
New Steering Knuckle Design that is lighter, more reliable and stiffer.
The new ST direct steering Knuckle is shown above
Provisions for Direct Knuckle Steering. This type of steering allows us to produce an Under-Seat Steering (USS) that is light as our Over Seat Steering tiller RS.
Universal disc brake caliper mounts, allows a wide variety of disc brake options.
Update (01/27/10) Seat is an integral part of the frame, making it stiffer, lighter and more reliable. The forward incline adds better support and prevents the rider's bottom from creeping forward. Back of seat will remain identical as original Spitfire.
Improved rear stays and drop outs, ensure better alignment and less horizontal flex. The new ovalized shaped rear stay tubes are contoured for a cleaner look and added stiffness.
Update (01/27/10) Frame system is simplified using a single gusset system. With the seat as an integral part of the frame, I can now eliminate the rear gusset and provides needed stiffness to the rear stays. My new sheet metal gusset provides vertical and yaw stiffening making the frame less complicated and adds more aesthetic quality to the trike. An aft sheet metal gusset will be used to retain vertical and yaw stiffness to the trikes rear section.
7005 series aluminum frame and seat. Although 6061-T6 has a slight weight to strength ratio, the need for heat treatment produced too many defects for us to economically control. This new frame will have better alignment quality than other Spitfires.
Ready For A Full 3D View?
Update (01/2710) In the following weeks I will be updating these 3D models to reflect most recent changes
For a full 3D interactive view of the ST Spitfire click here (Requires E-drawings 2004 or later)
For a full 3D interactive view of the RS Spitfire click here (Requires E-drawings 2004 or later)
Specification: (subject to change often)
|Total Length (depending on boom extension)||~83 inches|
|Total Width||31.7 inches|
|Wheel Track||29.5 inches|
|Ground Clearance||3.5 to 4.0 inches|
|Turning Circle||18.5 feet|
|Weight (depending on component selection)||28 to 31.5 lbs|
|Frame weight (painted) no steering hardware or seat sling||8.3 lbs|
|Complete Frame Set Weight (minus components/wheels)||~13.0 lbs|
|Crank Height (measured from center of BB to ground)||~18”, increases .44” for every inch extended|
|Seat Bottom Height||6.5 inches|
|Seat Width||17.2 inches|
|Seat Angle|| 34°
|Max. Weight||270 Lbs|
|Min X-seam||35 inches|
|Max X-seam||47 inches|
|Steering Configuration||OSS Steering Tiller|
|Center Point Angle||19°|
|Scrub Radius||~-.27 inches from tire contact patch|
A fully modeled image of our new ST (with optional upright seat)
Frame Design Features
Since the basic frame geometry of the RS24 proved to be a solid performer, only subtle changes were made to adapt a 26" rear wheel. Impressed by the results, I adapted the frame for both RS and ST models. To top it off, a few new enhancements were added that make this solid design even better.
Updated (01/27/10) One of the recognizable changes is the newly designed main and aft gussets. These contoured sheet metal parts replaces the tube gussets used on the RS24. The new gussets are lighter and less obtrusive. Another difference is the reduced main tube length. The shorter main tube makes the RS26 slightly shorter than the RS24 (with the boom removed), allowing easy shipment. In addition, it accommodates riders with shorter legs. The seat is now a fully integral part of the frame. This provides extra strength and stiffness to the rear end. Last, the sheet-metal bulkheads have been replaced with a machined aluminum billet that adds extra strength and provides a better fit and finish to the frame.
Changes to the seat assembly is a give and take. The seat angle is now fixed at 34 degrees and is no longer adjustable. The frame is also available with a 40◦ angle seat. As consolation, a generous incline to the forward tubes of the seat is provided so that the riders' bottom does not slide forward.
The steering system is similar to the RS24. I have made some enhancements that have both simplified and added more features to our existing system. Notably, I have added an angle adjustment to our club tiller handle. The new U-Joint now uses a Delrin Spider Block. This precludes the use of expensive pressed bronze bushings. The steering knuckles have been simplified to use a 20mm threaded wheel axle that does not require a costly 12 mm titanium axle. The steering arms are now now solid .75" x .5" billet aluminum that use a modular designed caliper adapter. This new design allows me to use a wide variety of disc brake systems.
The 3D model shows a complex knuckle system. Machining cost could make this too expensive to machine. Consequently, this part may be casted with limited machining.
The accommodations for standard accessories are built into the design of this trike. Therefore, accessories such as Fenders, Mirrors, Computer and water bottle mountings have all been carefully implemented. TBA - a few drawings that show how these accommodations are implemented.
Currently, I am currently considering offering both RS and ST26 as plans. However, the level of component groups should consist between the Shimano 105/Deore components or upgraded to Shimano's Dura-Ace/XTR or equivalent.
You want more information? Please email me, Rickey Horwitz at email@example.com.