From the last update, the two halves were bonded together.  Two layers of narrow carbon strips were laid at the joint line.  The bond between the two halves was also fortified by epoxy at the balsa blocks.  The main frame was then sanded and holes drilled for the various penetrations.  In the first PIC starting from left to right, the first is for the bottom bracket, then the support for the front wheel drive idler, then the front seat support.  The remaining two are for attaching the two frame halves together.  Also see detail of the penetrations.  In the critical areas, the carbon build-up is approximately .110-.120 inches.  The nominal thickness throughout is .075 inches.  The carbon density appears well permeated and compact which means that I removed most of the excess resin.  This main frame is far stiffer than my present BC.

The first PIC shows the carbon tubes which was purchased from Maclean Quality Composites.  The larger tube is 1.622 inches OD and the others are 1.400 and 1.300.  All are heavy wall of approximately .062 inches.  These will be used for the penetrations in way of the balsa blocks.  I have developed a way to insure epoxy saturation when inserting the tubes through the balsa.  I coat the balsa with thickened epoxy and a lighter coat on the tube using a stiff small epoxy brush.   The hole is just slightly larger than the tube.  Then I use a screwing action on the tube, at  the same time forcing more epoxy (by the brush bristles) longitudinally around it and in the direction of insertion.  When the tube is fully through the hole, you can see complete saturation on the other end.  The next two PICS show examples of this method.  The first is the tube in the headset area to be used for the front wheel drive idler, and the second PIC shows the tube through the rear wheel stays.  The last PIC shows the main frame on my fixture with the tubes installed and the frame given a light coat of clear.  The green tape just prevents paint from coating the opening of the tube because close fitting items will be installed.  More on this later!

Now I must start building the rear stays.  Shown in the first two PICS is the BC on the fixture.  Critical dimensions are taken so that they can be transferred to the new frame.  This will insure an exact copy of geometry.  Also see a PIC of the Rotor Cranks.  The left pedal is in the dead spot and the right one is advanced past the corresponding dead zone.

Shown here is the new X-Port main frame in the fixture and a rough plywood piece to mock up a single rear stay.  From this mockup a set of identical rear stays will be copied.

These PICS show the same setup, but the seat has been placed on the bike to show what the complete assembly will look like.  Note that the seat is, at this time, not at the correct angle.  It is only for visual purposed. 

Shown here was my original intent for a portion of the rear stays.  I made a sandwich core, what I call the spine, of carbon and Nomex.  The carbon is two unidirectional layers (90 degrees to each other) of .016 inch material.  Therefore each side is approximately .030 inch.  My original thinking was for the core to be Nomex.  I changed my mind with the Nomex because I liked the bonding chacteristics of balsa with cross tubes.  So I decided to use the carbon with ¼ inch balsa as the core.  To this spine I must add the rear dropouts, as well as the front section which will be attached to the main frame.  The latter is very important because that is where the frame will come apart for transportation.

Shown here is the plywood pattern with some of my choices for construction.  The large plate on the left is a piece of .110 X 8 X 116 inch. This was purchased from Aerospace Composite Products.  It is a high pressure cross pattern multi layer corelite construction.  Extremely light and super stiff, and a price tag to match! This will be used for the rear dropouts as well as the connection to the main frame.  I attempted to copy this in the piece shown on the right, built up to the same thickness.  Not only was mine heavier (by a bunch) but was not as stiff.  It has to do with their construction process.  I am confident the home builder cannot match the bonding pressure that is used in this process.  Needless to say I did not use my piece.  Next is the sheet of 90 degrees carbon previously mentioned?  This is shown lying on the table.

The first PIC shows the rear dropouts doubled up.  The second shows the result after many hours of drilling (not an easy task with this material) and sanding.  The resulting weight of the rear dropouts is now about 30 grams (for both) or just over an ounce. 

This is the beginning of the rear stay spine construction.    On the right is the pattern.  On the left is one side and in the middle is the other.  On the left one you can see the dropout on top, the corelite material towards the bottom, the balsa material in the center, and the 90 degree carbon is obviously behind the assembly and tying all together.  The middle one is the same but you can see the thin carbon and the balsa is hidden.

The first PIC shows the spine after the remaining side has been covered with the .030 inch 90 degree carbon cover.  Some sanding of surface and edges has been done at this time.  The second PIC shows lightning holes drilled in each spine.  Some major cross tubes will be bonded (shown clearer later) through and care was taken not to drill the spine in that area.

These 3 PICS show the rear stays after they have been covered with a layer of balsa.  A ¼ inch thick piece was put on the outboard side and a 3/32 piece on the inboard.  It was then sanded, shaped and hit with a primer to show surface imperfections.  The surface must be smooth here because two layers of carbon cloth will be wrapped around the assembly. 

I took a break from the rear stays construction to modify the front seat attachment.  At the heart of this design is for the seat to be apart of the frame strength.  I will go into more detail later.  This necessitates that the attachment points be as rigid as possible.  In the first PIC is shown a stock Optima front seat mount in aluminum.  Being the anal weight weenie that I am I drilled and milled off material from the top.  I did this to save weight primarily.  The unit will be bonded to the seat so excess aluminum was is not necessary.  The final mount is shown in the second PIC.

Getting back to the rear stays.  They are both covered with 2 layers of cloth and sanded.  The first PIC shows them individually and the second on the main frame.  Work is not finished yet, however!

Shown is the front seat bracket attached to the main frame.

This is the final step in the individual rear stay construction before assembly.  Holes are drilled for the following reasons.  The two holes on the right are for the connecting pins which attach main and rear frame.  The third hole (from the right) is for a major cross tube connecting stays. The fourth hole is for lightning and the last is for the major cross tube.  The brakes as well as the rear seat mount will be connected here.

The connection point of the rear to the main must be rock solid in order for this design to work.  That means that there must be metal to metal connection and on a flat surface so that the rear and front is not allowed to rotate or move.  I made inserts for the main frame and the rear.  This is shown in the first PIC.  The second shows a little more detail and the two pieces for the front seat mount.  I choose to make that from an epoxy/filler compound because I wanted to lighten up and this was adequate for the purpose.  Whenever I have excess epoxy left over from an application I pour it into a cup, put in some filler and perhaps a pigment (which is shown in the last PIC) and allowed to cure.  I then machine that down for bushings or whatever when ever I don’t want the weight of aluminum.  The result is rock hard, light and bonds extremely well to carbon.

The unit is tied together!  The rear dropout distance is set at 100 mm for a standard front wheel.  Again remember this is a FWD so the front is installed on the rear.  The main cross tubes are bonded in place and the metal inserts are bonded on the inside of the connecting arms. 

I must now present my design objective that will make the unit work as an integrated unit……or so I truly hope!  My design goal is to be as stiff a frame as my VK-2, built by Velokraft.  Kamil’s design works the way it does because of not only the front stiffness (boom) but also the rear.  He achieves this by integrating the inherent torsional strength of the seat into the frame.  While my BC has adequate boom stiffness, the rear is lacking.  This design copies from Kamil’s in that the front is as deep and wide (the balsa blocks also add a great deal) but the rear seat will be a strength member as well.  Looking at the first PIC I have rigidly attached a carbon clad balsa block and bonded it to the rear frame stays which are tied together by the 1.622 X .061 inch carbon tube.  There is a quote somewhere in the Bible that says “What God has but together, let no man put asunder.”  I don’t even think God can put this asunder!  I put aluminum pins through the block and threaded it for 6 mm bolts, which I use to attach the seat.  I then strengthened the underside of the seat to help transfer torsion to the seat channels on both sides.  The front bracket is also shown and was reinforced in the same manner.  I will keep all appraised as to the successful results of my theory……or lack thereof (successful results)!

The two parts are joined here!  These PICS show form fit and function without the seat installed.

Now for weight!  My goal was to get as close to Kamil’s VK-2 weight as possible, which was 2500 grams (5.51 pounds).  The weight at this time is 2850 grams (6.28 pounds).  I overbuilt the front main frame, and I have no regrets.  This bike will be much stiffer than my BC, and time will tell if it compares to the VK-2.  As a relative comparison, it was a long time ago but I recall the weight of the original aluminum Optima Baron with seat (it had very heavy stainless steel seat mounts) was in the vicinity of 11 pounds.  The weight of the M5 CLR, frame only with integrated seat was approximately 9 ½ pounds.  The weight of my BC was at least 8 ½ pounds and the main reason I lost control is because I had it professionally painted at a body shop.  The present bike will not be painted.  I have put a few very light clear coats, and I may add another coat, but that is it.  The finish, while showing a few pinholes is good enough for show purposes.  I am sure the final weight when I add the pins to attach front and rear half will front seat bolt will be close to 6 ½ pounds, which is about 18 % greater than the VK -2, but I am still on target to get a final all up weight of low 20 pound range barring FWD stuff getting out of control.

A few last PICS of the frame parts!  Shown in the first 3 are of the individual main frame halves.  The last 2 are meant to show a possible storage configuration.  I have a few cases that I have researched, but it is premature to show them at this point.  I will choose as small a case as can house the components.  Keep in mind that an option I have is to take the seat off.  There are only 2 bolts and removal is not a problem.  At this point, I plan on leaving it on.  Removal of the fork is absolutely out of the question.  I have a few neat ideas planned for the handlebar assembly.  This, my fork choice and a whole lot more in my next update.