Last weekend I got the suspension reinstalled onto the chassis and installed the pedals.
All that is left to do is install the brake lines and the electrical system. I don’t think this will take more than a day, but next week is finals week and I feel I must repress my desire to just finish it.
I also worked on the cluster. I managed to get a promising circuit together for the backlight controller. All that is left to do on that circuit is to solve for the capacitor and resistor values that will give me a 20% to 100% duty cycle between 18kHz and 22kHz frequency range (As required by the datasheet). I haven’t developed a circuit board yet as I still need to make one more circuit. The engine computer powers the sparks plugs. I haven’t placed an oscilloscope on it yet, but I imagine it is using a square wave to charge the plug and then discharge it, but due to the plug being a giant transformer it is probably going to have voltage spikes as well. I need to develop a circuit that can take this signal and feed it into the computer for the tachometer.
Now that I have all the systems on the trike worked out, it is time to tear it apart, touch up all the metal, fully weld everything, paint it, and do final assembly.
First, I want to cover some of the items I left out before.
The seat was designed to hold a driver and a passenger between the 38 inch width frame. Originally, this vehicle was designed to be a single person vehicle, but I decided to make it a two person vehicle after the chassis was completed. It is possible for two average-sized persons to fit in this seat despite it being a tight squeeze. The seat is made from 0.25″ plywood with angle aluminum holding the corners together. The wood was bolted to the aluminum. The plywood was then covered in 2″ foam. A steel box was developed and bolted into the center. This steel box was designed to hold the lap portion of the seat belt for both the driver and passenger. It bolts directly to the vehicle chassis independent of the wooden frame. My mom then did an amazing job making a cover for it out of pleather (vinyl leather substitute). Thanks mom!
I really wanted to go all out on the wiring. My idea was to run nothing but can-bus and power to all the modules. This would require making microcontrollers for all the modules (engine, headlights, taillights, cluster), but I’m under a time constraint to get this vehicle done by the end of the semester and present the project as an undergraduate study. Some items had to be scaled back. For the time being, this wiring harness is a simple logic of relays and a turn signal module.
After all the welding, I took a circular wire brush in a drill and took off some of the larger bits of rust. The rest of the rust was treated with PUR15. This leaves a zinc coating on the metal. That is why the chassis has a white appearance. I also filled in the seams with paintable seam sealer.
This was followed up with a primer. It started raining right after I got it painted. I had to shove it in the garage before I could get a picture.
Finally, I sprayed it with satin black. I did this using Rustoleum Oil-based paint thinned with acetone before being put into a spray gun. I don’t know for sure, but I assume this paint is similar to what Rustoleum puts in their rattle cans. The idea being even once this project is done, I may want to add some stuff to the chassis. It would be nice to grind of a small area of paint, weld on my new item, and rattle can the small area. Plus this paint can be had at the hardware store for <$10 a quart. I don’t know how well this paint will hold up to the sun or abrasion from normal use, but I will report back on this.
After all this, I’ve began final assembly as well as making sure all the small brackets are painted. I did this with rattle cans. For final assembly, I made sure everything is secured, welded properly, torqued properly, and do an inspection before attaching to the chassis. This is a slow process and so far I haven’t noticed anything wrong. It would be very incontinent to have to grind paint off and reweld something, but this is a small price to pay compared to having a part fail while going 70mph. In most modern vehicles 70mph doesn’t seem like much, but this is 102.7ft/sec!!! Not only is this a safety concern, but to lose two years of work to a simple mistake would be devastating.
This brings everything up-to-date with what I have done as of today (April 17, 2018), I am currently working on building the cluster. Here is a teaser of the cluster.
The cluster three boards seen here are the Raspberry Pi model B+, an HDMI-LCD Controller, and a buck converter (regulator). This is all designed to be mounted inside of the water proof box. There is also a GPS module. The idea is that the GPS module will provide speed over serial communication that can then be displayed on the screen. It is a quick and cheap solution (Other than the box, I already owned all the parts.) to make a speedometer. A speedometer is legally required for the vehicle to be road legal. The LCD screen is rated for 690nits. This is bright enough to be visible in direct sunlight. This is also too bright for night time visibility. My current project for this is to build a custom circuit board to control the brightness of the backlight based on the ambient lighting around. I would also like for the computer to have control over the backlight so that it can be turned on and off via software. This is my “quick and dirty” solution to hiding the on-screen display that shows up when the LCD is first turned on and the boot process of the computer.
The suspension was completely redone using a transverse leaf for the spring and two Gabriel air shocks for the shocks. Below is a picture of the leaf spring being fitted into place. This was done to see how the vehicle will sit and to adjust the length of the hangers from the leaf spring.
Finally, the test drive video. The test drive went well, the suspension worked great! There are some carburetor issues that I need to work out as it appears to be running lean.
Its been a while since I’ve updated, but be assured I’ve been working hard to get this vehicle done.
One thing I’ve been working on is the interior. The picture below shows the seat and the dash taking shape. Click on the picture for more information regarding the image.
The front suspension was also adjusted to sit correctly. This unfortunately is a failure. Read more by clicking the photo.
I wanted to make use of the wasted space behind the chassis. I added some angle iron to the back to make a trunk. Read more by clicking the photo.
Finally, I wanted to get the engine running, I began work on the wiring harness. First, I needed to order wire. To do so, I needed to know what gauge. Without knowing the specifications of the engine computer, I chose to measure the GL1200 wiring harness and go with that gauge.
Since the last update, I’ve added the sway bar, steering, and shock towers. I installed the knuckles, differential, and the brakes to sit the trike down on its suspensions to test what it looks like.
I should note that the shocks are air suspension from an 86 Honda Goldwing GL1200. They have springs inside, but the internal air bags are currently not inflated. It is worth noting that the camber on the wheels is off as well. This was on purpose so that they can be shimmed to the correct camber later. At the last second, I decided to modify the shock towers. They were originally designed to be about 4 inches apart across the top. I decided that I wanted the trike to sit as low as possible. At the last second, I changed my design so that the shocks would instead be about an inch apart. This resulted in the trike having a much more aggressive stance, but now the A-Arms are not sitting at a good angle and the bottom knuckles are bottoming out. I need to either lower the shock tower or widen it. The other option is to move the differential lower into the subframe, raise the subframe up and move the upper A-arms up as well. I’m currently leaning toward the second option. Tomorrow I plan on researching the amount of air required for the suspension and see where the suspension sits at that air. I plan on doing something more fun in the mean time while I wait on my decision on how to fix the suspension as well as the results of putting air in the shock.
The steering rack took a little more time than expected. Not only does it require precision, but it is also a rather expensive part to mess up. With a little time, I was able to cut it to the correct size and drill – tap it for the tie-rods. The knuckles are from a VW Jetta MK4 (99-05). The outer tie-rods that connect to the knuckle are also from the Jetta. The next step was to find inner tie-rods that had a small enough bolt to fit into the small steering rack, but also have the same bolt and thread as the Jetta’s outer tie-rod. Thanks to MOOG’s excellent catalog, I was able to find such an inner tie-rod. The inner tie-rods are MOOG EV414 (1998-2001 Honda CR-V)
I placed the sub-frame back onto the chassis to start designing the steering and suspension. I realized I needed to start getting an idea of how the seats were going to be before I could mount the steering wheel. As you can see in the photo, the 2 pieces of wood against the rear firewall are the two seats. The trike was original designed to be a single-seater, but part of the way through, I figured that it would be slightly more practical with two seats. With this design, it is possible to fit two people in the trike, but they better be a pretty good friend because there isn’t a whole lot of room.
Here I have the rear mount installed. The rear mount still need to be triangulated. The differential mount will provide much of the strength.
Here the sub-frame with the new rear mount install. The left control arm is also installed for mock up. It appears the control arm touches the rear mount. I will have to make clearance to fix that, but it also needs clearance so that the control arm can be greased via the grease fitting on the rear.
Though I meet my goals for today, I don’t believe I will have the engine back in tomorrow. I forgot about modifying the steering rack and mounting the steering wheel.
Goals for tomorrow:
I just got the front sub-frame mounted on its front mount. The next step will be the design the rear mount. The idea I currently have is shown by the yellow lines in the picture. Plate steel will attach to the “hockey puck” (shown in red) under the pedal box. The sub-frame is used to mount the steering rack and the front-differential for the electric motor. Since the front differential may need to be serviced, I came up with the sub-frame design to house the differential so that it may be removed. The differential and its large cast iron body will also serve as a structure member for the front suspension. My goal is to have the trike sitting back on its suspension by tomorrow morning and have the engine back in it by tomorrows end.
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