The auto racing season is underway. The 40th Advanced Auto Parts Clash (originally the Busch Clash) ran at Daytona this afternoon (congrats Brad Keselowski on the win) and as I type this the semifinal rounds of the NHRA Winternationals are live on the
tube flat screen. I have never been a drag racer, but they are fun to watch. As an engineering problem the physics are fascinating. The ultimate goal in drag racing is to reach the finish line immediately after the light turns green on the start line either 1320 or 1000 feet away, driven by the wheels in most classes. The chemical and physical bonds between the tires and the track, the thermodynamics inside the engine as fuel is turned into power, and the mechanical transmission of that power to those bonds at the tires, that to me is fun.
SCCA Solo racing is drag racing with left and right turns, so there is some overlap in application to my kind of auto racing in terms of execution but almost nothing in engineering. Drag racing has no lateral acceleration as long as everything runs right as shown when Brittany Force wrecked in the first round of Top Fuel. The word is there will be a report from the hospital at 0800 Pacific on her condition. I sincerely hope she will be OK. For a sport so embedded with fossil fuel use and abuse, there are a surprising number of bicycles in use in the pits and elsewhere in drag racing, so some of Them are really Us.
Brain shutdown thoughts have been on the fact I haven’t included the mounts for the rear springs and swing arms in my plans for the Sprint-T frame. They have a specific place they have to be because the swing arms have a fixed length and connect to something that has to be in a certain place, and they have to be braced in at least two directions so the rear axle doesn’t move around and steer the car from the back independently of what is input at the front. Which is the reason why I didn’t design in roll steer for the rear suspension, because roll steer becomes rear bump steer when you’re just driving down a bumpy road. The slight performance advantage possible racing is more than offset by the possibility of losing control racing or driving on the street. So, the swing arms are level at normal ride height, preventing roll steer or rear bump steer.
And the cat is trying to sit on the laptop so I guess I’m finished.
I was just outside Lebanon TN where we got 2:30 (+/-) of totality. It was really neat to watch the shadows dance from the light cast by the corona. And I could see Sirius and Venus during the eclipse. At least I assume that “star” in line with the sun was Sirius, might have been something else.
Also I got some kind of stomach bug on the bus trip to Nashvegas and got to make several trips to the toilet working up to the eclipse, or maybe something I’m allergic to messed me up. Anyway I had diarrhea (sp?) most of the time I was in TN. Fun times.
I had lots of time to think about the TGS2 while I was not stuck on the toilet. One of the things I was thinking about was that the transmission would probably stick out the left side of the body where it tucked under to meet the frame because it is closer to 40″ wide there and the frame is 34″ wide. I could do two things to “fix” that. Easiest would be just go ahead and cut the bottom of the body for clearance and live with the tranny sticking out the side of the body in front of the rear suspension. The other thing I could do is raise the body to clear the transmission and any part of the engine that might stick out. Then make a cover to hide all the bits not hidden inside the body. I have also been thinking about moving the bucket back forward and making an extended pickup bed to cover the engine and bits, and the fuel cell. That’s easier to make fit around the bits but looks funny. But does it look more strange than the cockpit in front of the body or less?
I also had time to look up tuning for running strictly on e85 ignoring the possibility of using premium unleaded gasoline. One thing I would need to do is raise the compression ratio to about 14:1 to take advantage of the high research octane number, and remove any sharp edges on the top of the piston or combustion chamber in the head and polish the combustion chamber to prevent pre-ignition. Doing this will get me part-throttle fuel economy similar to the stock engine on gas with about 40% more power at full throttle. That means highway mileage similar to the minivan I took the engine from and better in-town mileage (because the TGS2 is about 1300 +/- pounds compared to 3900 +/- for the minivan). So I’m looking at 25 +/- MPG highway and well over 16 around town. And a 32 gallon fuel cell to go with that for long stretches between e85 stations out west, over 800 miles if needed
I did some sketches of what the front fenders would look like with the headlights faired into them… Can I just say ugly with a capital UGH!? I’m debating if the reduced drag is worth the damage to the esthetics. Since the top speed is going to be limited by the gearing in the transmission anyway, and I wouldn’t be able to see the difference in fuel mileage fairing in the headlights is strictly a matter of appearances. Now if I could track down some headlight buckets for mounting the 5 3/4” headlights I had originally planned on using since they are OK here in TX when used as single (per side) headlights as long as I use the motorcycle versions. They have under the maximum high beam light output but well above the minimum, so everything is copacetic on that front. I will be able to see where I’m driving at night without blinding oncoming drivers. And the smaller headlights also look better when faired into the fenders.
And right now I need to have a lie down because my back is still having painful spasms and I’m sweating like pigs can’t because of it.
I’m dealing with two problems today. One is my sleep schedule is all bolluxed. The other related is it only cools off in here around Midnight. And by “cool off” I mean near 80°F. As I type this it’s 0130 and 84° in my office. I have a fan blowing on me so it’s not too bad as long as I remember to hydrate and drink cool liquids, no coffee. Another thing I can do is take my sleep medicine so that I can get to sleep by 0300 and be up by 1100.
I knew the junk mail would eventually send me another card I could use for the TGS2. It came (what is now) yesterday. I should be able to take a picture of the finished floor by Saturday since I already know how to do the front cutouts, and have a very good idea of how I want to do the rear cutouts. I still don’t know how I want to do the rear fenders, but I do know that if I get them right I will get less drag and more downforce especially compared to running no fenders. I guess I can make temp fenders out of HDPE and do A-B-A testing until I settle on a final design and make that one out of more durable materials.
The bushings are still not installed in the spindles. I spent hours beating on them to try to get them in the spindles, but there is one that doesn’t want to go into the spindle, and all but one will need to be drilled for grease holes where the zerks go in the spindles because the factory grease hole didn’t line up because I installed the bushing wrong or because I’m discovering why these spindles were in the Garage Sale section of the web site. Take your pick. I can tell you that 2 bushings would never line up because they were too short or the hole in the spindle too long, but they would line up if they were installed from the side where there is no room to install them. And that says to me that there was a machining step left out somewhere. Ah well, it is what it is and I have to find a way around that.
OK I have been sitting here sweating like pigs don’t (that’s why they roll in the mud) and I need to take my sleeping pills and go to bed.