Paul Jones Coroplast Full fairing on his Rotator Recumbent Bicycle HPV Bike
Rotator Pursuit Coroplast fairing
By Paul Jones
About 4 months after buying my first recumbent, a Rotator Pursuit, a natural progression caused me to search for more speed. The following describes the building process that led me to a full fairing. 

I am not qualified (in my opinion) to write an interesting article about building, but I had a difficult time finding information on attempts to fair a Pursuit, and felt an obligation to others going through the same thing. 

I had been riding with a tail box for a couple months, made of 4mm Coroplast attached to the seat frame with zip ties. The grain of Coroplast is vertical on the sides. I used Warren's method published on his WISIL site to radius the top and bottom folds using a heat gun. The bottom piece comes up to around 6" from the top, and is joined to the top piece with zip ties and Coroplast backing strip. To strengthen the shape, there is a shelf running the length of the tail box, sloping down slightly to the rear and attached to the sides with zip ties. Great place to store long items like pumps and Camelbacks. I made the tail box 32" long at the top, satisfying the formula of twice as long as wide for good aerodynamics, and the same height as my shoulders. The bottom is cut out for the wheel, but is above the drive train.

Wanting to build a full fairing, I ordered 2 sheets of 2mm Coroplast from a supply house in Sacramento called Lairds Plastic, paid $14 a 4x8 sheet. Too much in my mind, but they were the only place that didn't require a full pallet minimum order. 

2/08/2001
My first move was to build a frame to mount the fairing to. I used aluminum channel from my local hardware store, a couple 4' pieces. The pair are 
on either side of the seat, running parallel with the frame tube. One end is bolted to the seat, using the 2 lower threaded holes in the seat frame. Make sure the seat is centered to the frame, otherwise your fairing rails will be off center too. The front of these fairing rails are mounted to PVC pipe that attach to the head tube using a tee (sawed to allow hose clamps attachment to head tube) and a PVC cross (see picture). You can see the elbows on either side of the cross attached to the frame rails with rivets. The forward end of the cross is piped to the curved horizontal aluminum flat bar (3/4 x 1/8) that forms the shape of the nose. 
Attach radiused hoops of aluminum flat bar (3/4 x 1/8), at strategic points along the top and bottom, to the fairing rails (use rivets). I put one near the upper end point of the fairing...a couple inches from the point the handlebars would interfere in a tight turn, and another above the head tube. Radius them by eyesight, it will be pretty close...whatever looks good to you. Attach similar hoops to the underside. I put one directly under the mid drive, because it is the lowest point of the bike outside the protection of 
the wheels (have it in the lowest position), the other below the crankset. 

To provide a sturdy mount for the upper part of the fairing, I used 1-1/2" PVC tee cut in half and hose-clamped to the main frame tube. The top of 
the tee is bushed down to a 1" riser, extending to a 1" tee. Rivet a piece of 1" x 1/8" flat bar to the top of the tee, bend both sides upward about 45 
degrees so your knees will clear when peddling. Attach the ends (bent again to match the shape of the hoop) to the upper hoop (mentioned earlier) 
with rivets. The height of this piece is important...you should be able to look over the hoop and see an acceptably close distance from the front of your bike.

The framework is pretty much complete. Now comes the fun part...attaching the Coroplast.

Start with the lower section...the belly pan. Take a 4' x 8' piece of 2mm Coroplast (more flexible than 4mm). The bends will be made across the grain. This direction will provide the necessary stiffness and won't be prematurely bending at places you hadn't planned. Mark the halfway point on both of the 8' sides and mark every 2" for 8" on either side. You end up with 9 marks to guide by during the bending process. Clamp to a narrow board, stood on end, and use a heat gun to make it pliable enough to bend. 
This takes time to experiment...use scrap pieces and take your time. Too much heat and it distorts the surface, too much pressure to bend cold and the color changes.

The top is bent using the same method.

The top of the nose is formed by slicing the top at 3 - 4" intervals and cutting to allow strips to meet at front horizontal flat bar. The front wheel fairing is attached to the fork, and turns with the steering (of course). This was tough to accomplish...and required an elaborate (for my limited skills) framework of 3/4 x 1/8 flat bar, bolted to the fork with rubber-coated cable clamps. It had no vertical stability, so I attached the framework to the front fender (rivets again) to solve that. I could 
have left the entire thing frame-mounted, but wanted to narrow the opening for the 
front wheel....similar to Steve Delaire's Super Seven and Cargo Carrier design, just a lot more crude.

It is important to test ride at certain milestones of building to ensure you don't have to rework anything...like your feet hitting PVC parts or the 
rails being too narrow for your liking. 

By all means, don't get in a hurry...and accept all failures that come along as learning experiences. If you think you have a wonderful idea, wait a couple days to put it into practice, and during that time re-examine it several times.

I must have gone through 200 zip ties putting this thing together. Yes, it is ugly with 2 colors. Yes, it has mistakes. But it is so much fun that I don't care. 

2/10/2003
These pictures are my '00 Rotator Pursuit with 4mm Coroplast fairing. I'm not quite finished with this revision, but wanted to take some shots while I had access to a digital camera. The body is shaped with a heat gun, attached via PVC to the Pursuit. Nosepiece is a fiberglass scrap. The lower tail and door openings need to be completed yet. Thanks to each of you for sharing information...truly a community atmosphere. Maybe these pictures will help someone with their project. 

Click on the pictures for a larger view

I wanted to build another Coroplast fairing to include a more-aero nose and a canopy. Last January I came across a fiberglass nose and polycarbonate canopy, and they took up their space in the garage until November. I used 3 sheets of 4x8, 4mm red Coroplast for this project. The upper front was first to be shaped with a heat gun and mounted using PVC pipe to the main frame tube and head tube with hose clamps. The nose was mounted to this upper piece using scrap pieces of Coroplast, spacing them about 3" apart, zip tying the scrap pieces to the backside of both the nose and upper fairing. You can fine-tune the transition with varying thickness shims of scrap pieces, to provide a smooth mating surface instead of a noticeable step. 
The next step was the belly pan, shaped with a heat gun and mounted to small aluminum channel on both sides. The channels are mounted to the seat and another PVC section mounted to the head tube. I lowered the front PVC section by using 45's on either side, in turn lowering the elevation of the aluminum channel, allowing easier entry and stiffening up the front of the belly pan.

The seat width wasn't enough to clear my shoulders, so I added a 1/2" PVC support frame for the rear fairing and mounted it to the threaded holes on the sides of the seat frame (thanks to Steve Delaire's design). The shoulder area is wider than the hip area. Tail section was 2 pieces...starting with the upper, zip tying to the PVC frame and incorporating a shelf / stiffener running from the top of the seat-back to the rear of the tail. The canopy was last to be installed, requiring trimming to allow swinging of the tiller.

The lower tail was recently added (not in photos) and it cleans up the lines. Also added were doors, hinged at the front with half-cut Coroplast backing strips and attached to the rear using Velcro and bungee straps. There is a gap of about 5 inches on either side between the top of the door and the canopy.

I've been working on the motor lately...even with my developing legs, it has plenty of yee-haw. Just keep it in the garage on days when the trees are bending over, but on days when they're just swaying it can be a lot of fun.

Take a chance...build one that is in your head. You won't regret it.

Paul Jones
Northern CA

 

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