"Why don't we...?"
Revision as of 07:19, 16 August 2015 by Llohman (Created page with "This page is a compilation of ideas that seem good, and often are, but aren't on the car. With each idea is an explanation of why it hasn't been done yet, or why it should be....")
This page is a compilation of ideas that seem good, and often are, but aren't on the car. With each idea is an explanation of why it hasn't been done yet, or why it should be.
- Why don't we have a removable gas tank? We've considered it; it would make refueling faster and make the car more serviceable. In exchange for this, however, we'd need a much more complex mounting system, we'd have to include 2 gas tanks on the cost report, and the whole thing would have to be fully enclosed, adding weight and taking up space. Also, removable tanks have been known to fly off when you flip.
- Why don't we have a duct or intake to cool the CVT? The problems we've had with CVTs overheating were due to a combination of poor tuning (engaging at idle) and an all-fiberglass CVT guard. When we tuned better and included steel in the CVT guard, the CVT stopped overheating, so there was no need to cool it more. This may be reconsidered if we change CVTs or run into more issues with cooling.
- Why don't we mount the gas tank lower? This would improve the car's CG, and it might allow the rear bracing to be smaller. However, this tighter packaging would make the car less serviceable, as the engine, gearbox, CVT and gas tank would be less accessible. It's worth exploring exactly where to draw the line between performance and serviceability.
- Why don't we have a wedge-type frame instead of a rear bracing? This has been considered, most recently for the 2014-15 season. Preliminary analysis indicated that a wedge design would be about as strong as the rear-bracing design, but heavier. Also, we're more familiar with the rear-bracing design and can optimize it instead of starting from scratch.
- Why don't we have longer suspension links? Longer links are generally a good thing, since they give less camber change and toe change for a given amount of bump or droop. The ball joints are mounted somewhat inside the wheel partly to make the links longer. If we wanted longer links, we could either make the track wider or shrink the footbox and rear bracing. However, shrinking the footbox and rear bracing is tough for packaging, and we aim for a track width close to that of most top cars: front 50.5", rear 48".
- Why don't we use trailing arms/multilink/a live axle? We have used trailing arms in the past, switching to H-arms for the 2014-15 season. H-arms were better for serviceability, as accessing the CVT no longer meant removing the shock. There are other reasons that you can ask the suspension people about. Multilink is very complicated and we'd be starting from scratch on a very complex kind of suspension geometry, which generally isn't good. A live axle was used most recently on the 2010 car, but was abandoned in favor of independent suspension for performance and weight reasons.
- Why are our uprights so overbuilt? They're overbuilt because it's a huge problem if one breaks. They're a critical part of the car, they're expensive and time-consuming to make, and they're difficult to analyze and optimize because there are so many forces in all different directions.
- Why don't we have rear steer instead of front steer? We have used rear steer in the past, switching to front steer in the 2015 car. Rear steer protects the tie rods from impact, but it makes packaging in the footbox more difficult and tends to put the driver's feet in awkward positions. The rack cover is also easier to make when the rack is farther forward.
- Why don't we have butterfly steering? This is a goal for future cars. Last time we tried to incorporate it, we failed because a supplier gave us the wrong information. It is harder to package on the upright, since butterfly geometry generally moves the tie rod mounting point closer to the spindle and ball joints. However, it would improve driveability and controllability.
- Why don't we have an adjustable steering column? This has been done in the past. The short answer is that we haven't found a way to make an adjustable column that holds up to the forces that could be put on it. The lack of adjustability hasn't been a big enough problem that we feel the need to fix it.
- Why don't we use the thinnest allowable material for the firewall? This would cut some weight, which is never a bad thing. However, past teams have tried it and reported that such thin material is difficult to work with, and the increase in serviceability is worth the increase in weight.
- Why is our firewall two separate pieces? This is another change implemented on the 2015 car. A one-piece firewall was very difficult to install on the car, especially if its tolerances were tight to avoid gaps that had to be patched later.
- Why don't we remove material from the hubs? We haven't in the past due to a lack of time. This would be good to do, as it removes overall weight and reduces the rotational inertia of things connected to the engine.
- Why don't we web any tabs? Making holes means a slightly higher cost, and the gain in performance hasn't been worth the hit on cost. This may change if we look into other methods of making tabs, i.e. water jetting.
- Why don't we use aluminum for suspension links/tie rods/CVT band/other stuff? Because we haven't figured out how to weld it yet. This is also worth looking into.