Rick Wianecki builds the frank-n-liner recumbent hpv streamliner bicycle
Rick Wianecki builds 
the Frank-n-liner

By Rick Wianecki

 1-Design and mold     2-Fairing     3-Subframe     4-Tub    5-Drivetrain    6-Attach Top   7-Bodywork  8-PreRace
Subframe Construction
6/16/06
Before I can start fabricating the front sub-frame I need to make several of the parts that will be bonded into to it.

I will be using a custom Phil Wood bottom bracket
The bottom bracket requires a narrow shell to hold the bearings. I used a 1 ½” heavy walled tube and machined the ends to accept the bearings leaving a 0.10” wide lip on the middle to prevent the bearings from sliding one way or the other. The total width of the shell is 1”.
 I want to be able to adjust the position the bottom bracket. I will make a sliding assembly that will allow the position of the bottom bracket to change 5”. First I made 2 sliders that the bottom bracket shell will be attached to. I used 1”x .058 tubes with 6mm binder bolts. Here is the setup before it was brazed.
Here is the slider after it is brazed and before a slot is cut between the centers of the binder bolts.
Next I tack brazed the bottom bracket shell to the sliders making sure the sliders were parallel to each other.
Then I slid 7/8” tubes through the sliders and attached them to some pieces of 1” square tubes. It took some time to get everything aligned so the bottom bracket shell would slide easily. I also machined a 2” piece of steel to be a tight fit inside the bottom bracket shell so it remained round when the final brazing was done.
Here the bottom bracket assembly is placed on the full size pattern for the front sub frame.
Next it was time to make a carbon head tube. An aluminum mandrel was turned on my lathe and wrapped with plastic wrap. A 30” x 7 ½” strip of 10 oz. carbon cloth was cut and placed on a piece of plastic sheeting.
Once the carbon cloth was thoroughly wetted with epoxy, it was carefully wound on the mandrel starting at one end.
I tried to keep the cloth centered on and wound tightly to the mandrel. The epoxy makes it hard to keep a firm grip. I changed my gloves several time doing this.
Once all the cloth is wound on the mandrel, I wound a shrink-wrap tape over the wetted carbon to compress it and remove excess epoxy.
Tape was wrapped starting on one end and overlapped 50% in a spiral pattern.
A piece of duct tap was used to hold the end from unwrapping. A heat gun was used to shrink the tape and squeeze any excess resin. The assembly was placed on sheet of plastic to cure overnight.
The ends of the carbon head tube were cut off exposing a section of the mandrel. This end was chucked in the lathe. Several cuts with the lathe were done to true up the ends and shave off some of the excess carbon to make the head tube round. A shop vac is used to catch the carbon shavings as the piece is cut. 
Now it is time to make the sub frame that will hold the bottom bracket and the head tube. A full sized pattern is laid on a piece if 1” urethane foam. The foam will be cut to the shape of the pattern and covered in several layers of carbon.
6/19/06
To make the front sub frame I cut some ½” and 1” thick urethane foam to the desired shape and then cover with several layers of carbon fiber. I cut the 1” foam to the shape of the full-size pattern and then cut several pieces of ½” foam that will be glued to the 1” foam to increase the thickness of the sub frame at the head tube area and along the bottom at the front. The ½” foam is shaped with some sandpaper to feather the sides.  
The pieces of 1/2” foam are glued on one side of the 1” foam and the hole is cut for the bottom bracket assembly 
The next step is to lightly spray glue several layers of 10oz carbon cloth to the foam. The foam is covered with carbon on 3 sides. The carbon cloth is placed at a 45 deg. orientation.
Once the carbon is glued to the foam, peel ply and breather fabrics are cut to the correct size. These pieces are set aside and will be used after the epoxy is applied. 
I am going to vacuum bad these parts so I need to make the bag. Garrie Hill lent me his heat sealer and it took some time to figure it out and get it to work, but eventually I was able to create a vacuum tight bag.
The bag will be hooked up to a small vacuum pump that I have. 
Once I had everything ready I brushed on a coat of epoxy over the carbon and foam. I then placed the peel ply trying to get it as smooth as possible. Then covered everything with the breather. The pieces were placed on a plastic covered piece of MDF, placed in the bag, and left to cure overnight. 
The next day I removed the pieces from the bag and removed the breather and peel ply. The sides were sanded to remove excess carbon. 
Now I glued the other pieces of ½” foam to the non-carboned side of the sub frame.
This side of the sub frame is covered with carbon cloth on 3 sides. 
The pieces were covered with epoxy, peel ply, and breather and placed in the bag. This time the piece of MDF was not used. Care needs to be taken to remove as many wrinkles from the fabrics as possible. The pieces were left to cure overnight.
Here are the final pieces of the sub frame. The head tube needs to be bonded in and the steering support will be attached once the sub frame is attached to the tub. 
This is a view looking at the front of the sub frame that shows the thickened sections. The center section needs to be 1” thick to provide clearance for the chain ring. 
Next I will make the mounting brackets for the rear wheel and then apply carbon to the inside of the Tub on the Tub Fabrication page  
   

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