Still thinking about making the TGS2 lighter and simpler to build and I had a minor revelation. If I lower the 3″ tube until it is on the axle centerline that will reduce the bending moment enough to not need any bracing other than what is provided by the double-shear spring mounts (that’s a plate on either side of the coilover heim with the mounting bolt going through both plates) welded to the top. That unloads the top radius rod on the 4 link allowing for higher loads from restraining the brake rotation etc.
Someone asked me IRL how I know there is going to be so much weight in the back of the car. That one is simple: The engine and trans combined weigh 620 pounds with the CG about 10″ in front of the rear axle centerline on a car with a 100″ wheelbase that will weigh about 1600 pounds. I’ll let you do the math yourself, after I set the equation up for you. The arm for the drivetrain is 90″ and the weight is 620. The arm for the rest of the car is going to be 40″ if we are incredibly lucky, probably real close to 50″ split the difference and call it 45″ and the weight is 980. Moment is weight times arm. Add the moments together and divide by weight. That is the total arm of the car, between 63 and 65.5 and since we used the front axle as zero datum and we have a 100″ wheelbase that makes the rear percentage equal to the momentarm, I.E. between 63 and 65.5 percent. I learned this one when I was taught weights and balances for flying. Yes, I used to be a pilot before the wreck. Sioux this one was for you 😀 Math IRL for your students. Oh and the reason I don’t know the exact arm for the rest of the car is there are a bunch of parts I don’t know the exact weight for nor where they will go on the car when it’s finished. So I had to use a SWAG for the arm of the car without engine.
Excuse me I zoned out for a moment listening to an old piece from the ’70s on YTM; Mike Oldfield’s “Tubular Bells (Pt.I)”. They had just gotten to a part of the piece I call “The Procession of the Instruments” that starts about 17:00 into the piece, and continues to the end of Side One of the LP. This was one of my first experiences listening to polyrhythmic music, which my mind finds very relaxing. Anyway, Mike says the name of the instrument and they bring it up in the right channel then mix it over to the center front then over to the left and back but still up enough to hear if you focus on the sound. I didn’t know this at the time but polyrhythmic music has a calming effect on people with ADHD and PTSD. At the time there wasn’t any such thing as PTSD by that name, it was “Shell Shock” and didn’t happen to kids (that they knew), but I had been diagnosed with “something” tied to my high IQ, that we now know as ADHD. Anywho, when I listen to polyrhythmic music I zone a bit and get real calm.
Back to the car, I’m really feeling torn between totally enclosing the roof and windows and saving weight. Putting a roof and windows on it will make the car look more complete, but will need A/C in the summer. Or I could figure out some other way to keep dew and rain off the instruments and save about 50 pounds, most of it off the back of the car, by leaving the A/C in the donor vehicle and cooling the car by leaving the windows off. That would save even more weight but lower the gas mileage on the Interstate a bit. Basically all I really need is something to cover the cluster and seat when I’m not driving. I could make a snap-on cover like old hot rods and sports cars used in the ’40s and ’50s, called a tonneau. These days a tonneau is basically the thing that goes over the pickup bed when it’s empty, but back then it kept the interior clean and dry when the roof was down or if there wasn’t any roof at all. I bet I could make something with the HDPE sheet and some Velcroâ„¢ and get the same effect and roll it up inside the car when I was driving.
And I think I have meandered across the screen enough for today.
Witch on a Bicycle 