David Bruce Trikes prototype FWD Recumbent Tricycle!

Prototype 1

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Continued from DB History page... After moving to Cocoa Beach, I was doing other things and the FWD Recumbent Tricycle had to take a back seat. I kept drawing and thinking of ideas. I had inquired at local machine shops and their prices were just so ridiculous! So, in 2005 I bought my own metal lathe/mill combo and started to learn how to machine parts up. I had a house then so the garage became the shop. These pictures below show some of the early design and concept.

In between November 2007 and June 2009 I was working 60 plus hours a week so I had very few hours during the week to make stuff. I kept plugging away on the inboard brake design despite nagging doubts with the power transfer to the left wheel and limited cog size to a "24". In June of 2009 I got layed off from work, so then I had plenty of time to do stuff! The frame was together and I was using the driveway slope to test the steering geometry. These pictures below show some of the early design and concepts with some testing setups. Almost everything had to be made!

From July 2009 to November 2009 I spent a lot of time reworking the shock mounts and redid my suspension arms, including a set with adjustable castor to fine tune the steering geometry...which was a major pain! I had done a lot of research on the angles for the big three: King Pin, Castor and Camber. But in the end I had excessive castor and king pin angles which made turning extremely difficult. So, I ended up redoing a lot of stuff! I went with less castor, fine tuned the king pin angle and increased the steering arms for more leverage. In November 2009 I rigged up the trike for a test ride, using only the right shaft to drive the wheel. After that "event" I realized I couldn't rush things to test ride! I realized the inboard brakes were not going to work with a single chain. In addition, I failed to come up with a working "power coupler" to the left wheel. Which meant a big decision: either abandon the whole thing, or re-configure the trike for outboard brakes with a center differential...meaning remake just about everything in the center power block. I spent much of December 2009 deciding. I'm not a quitter, so I decided to start over! First thing was to make a differential that would work with my design. The diff would have to fit inside a housing and be small in diameter. Commercially available diffs are too big and are designed to hang between "dropouts" or dual frame supports. A long time ago I had a differential design made, and made my new prototype diff in a similar way, however I added thrust bearings and redid the power block:

From February 2010 to August 2010 what little time I had, as I started working again was spent on new tooling. I decided to spend money on the aluminum framing material to make a decent workstand and frame jig. I spent some money on a digital angle indicator and tried to make very precise jigs and fittings. I also spent time on making the steel frame and other parts to get the trike ready for a "real" test ride. The use of steel tubing for the frame meant I could braze it myself.

In September 2010 I decided to make a new rear frame and had the trike powder coated and chromed. I kept fiddling with the "Y" handlebar setup and shifter arrangement and right before the Trike Rally settled on a conventional Bar End shifter set up. The sway bar was made and fitted the night before the Rally to improve the cornering at speed. The new trike layout will be similar with aluminum front and rear frame pieces with a determination to reduce weight and simplify things where ever possible. But, at the same time add a safety and reliability factor for stronger riders.

Some pictures from December 2011, over a year since our first ride! We've learned a lot as each ride is treated like a test ride! Nothing has broken! During the past month I've modified the prototype for the new aluminum front and rear frame sections. These are identical to the frame pieces planned for the 4 FWD pre-production trikes. So I'll get some real world testing.

The Trike is made up of 3 main sections: The Power Block, Front Frame and Rear Frame. These are bolted onto the Power Block with the aluminum Suspension arms. Once on, the front frame has no need to come off except for a total disassembly. The Rear Frame attaches with three 8mm bolts for easy transport in small vehicles. Remember, Front Wheel Drive has no chain to the rear wheel, no shifter cables and no rear brake cable ( unless added as a option.)

Wheelbase is approx 41 inches and Front Track is 28.5 inches. The wheels are the 451mm rim sized 20 x 1.125 tires. Primo Comets are currently being used. The prototype weight is 39 pounds without water, tools or travel storage bags mounted after the new modifications.

Shock travel is approx 1 inch and road clearance is 2 inches.

New Aluminum Front Boom with accessory post.

Rear Aluminum Frame configuration.

DBT4 Emblem without chrome or detailing. Serial Number will be stamped here.

Bolt on Rear Dropout, with threaded holes for accessory mounts.

Rear seat support adjustable clamp (prototype testing part).