I'd say we'd need a push truck with gearing and torque to hit 150 max speed by the 1/2 mile mark.
The benefit of pushing to 150 by the 1/2 is the removal of any need for brakes or parachutes on the car since the resulting crash will slide/tumble to a stop around the one.
This also has the added benefit of allowing the safety equipment to be pre-staged there since the final location of the accident debris is pretty much a given.
Have you ever driven a pushee at 150 mph. A bit on the difficult scale.
DW
So all you need is a push truck that will go 150 while push starting your liner in 1/2 mile? On salt? Sounds like you need to start a new build diary. This is going to be a pretty fast pickup.
Hi All...
Good points with valid concerns, thanks for the thought provoking comments. I agree that conventionally pushing a design like this to high speed is troublesome to say the least. But there's not much about this design effort that's conventional is there? So let me comment for a bit about why I think this current design is desirable over previous versions and then address the push vehicle.
Let's consider existing conditions that must be overcome for successful results. Based on what I've read from you traction is the #1 limiting factor for record speeds. Aerodynamic is #2, stability #3 (due in large part to limited traction), and available hp last. Please tell me if that's wrong, needs reordering or additional items...
#1: Traction is not a problem here because of low torque and 1:1 gearing. I've eliminated the active aero flap for V.5.8 because of the change in torque characteristics over the previous 100% torque electric motor drive. When the IC engines light up at 2200 rpm the power curve up to max rpm should be progressively strong depending on port and ignition timing, total weight, and applied power adders. Based on IO's input I recognized that weight will be an extremely important issue in how the car performs given the new IC direct drive powertrain.
So, I research to find the best way to affordably apply Carbon Fiber (CF) into the chassis build. 2" x .085 wall high modulus CF square tubing, bonded 3D printed titanium connectors, and bolted/bonded 1/2" multi-directional layered CF plate can be applied to form a super strong/stiff light weight space frame truss chassis. I'll probably use the same construction technique for the drivers tub instead of the molded design as currently shown. It's easier to build and cost less overall.
#2: Aerodynamically I think the current design at 4 sq.ft FA and low Cd shape is competitive compared to others I've been able to study.
#3: Stability wise moving away from rear wheel drive to forward drive should greatly help deal with yaw problems that plague more conventional designs, especially since the current plan is to use the DF chassis layout. The reported stability of the Salt Shark FWD car convinced me forward drive is the way to go if enough traction can be found to eliminate rear drive wheels. We may even reduced the number of drive wheels from 6 back to two using a stacked inline rotor configuration with a forward steering differential and no transmission. We could then experiment with different diff gearing to help tune the power curve given that rotary IC engine(s) are good to 10,000 rpm max. That would also eliminate the mechanically disconnected IC powerplants as seen in V.5.8.
#4: Push Vehicle. Pushing this design from the rear would effectively amount to rear steering from 0 to 150 mph. I assume everyone agrees that's the wrong approach to take. However, given a safe alternative I would argue that push starting to somewhere in that speed range to take advantage of the direct drive platform for potential max speed is very desirable. So here's one alternative that I believe could be safely applied.
If one were to pull this design from the front rather than push from the rear it would be inherently stable up to and beyond LSR applied power. Knowing that we can't use a tow vehicle to start we need a new design push truck that accomplished the same result from the rear. A conventional pick up truck isn't the best approach IMO. We need a custrom built, horse shoe shaped vehicle that surrounds the LSR car from the rear leaving the front open for the LSR to pull away under its own power at the right rpm.
Each leg of the push "shoe" running either side of the LSR would make a "push" connection to the LSR through forward mounted booms that connect with the LSR at nose contact points on each side that effectively "push" the LSR forward up to speed. Either upon push shoe braking or LSR power, or both, the LSR would pull way and make its run. The push shoe would then steer off track conventionally and head to the other end.
Effectively, the push shoe truck could also act as a powered exoskeleton trailer that lifts the LSR off the track for maneuvering around the pits and turn around at the end of the track after each run. Run a sprung dually real axle mated to a turbo diesel or even better a high torque electric motor geared to max out at the 1/2 mile marker. Use sprung wheels at the nose of each shoe leg for steering with the shoe driver sitting wherever best serves his purpose and control of the vehicle. Use of a light space frame with roll cage protection for the shoe driver should produce total weight of the two vehicles less than a big dually pick up truck alone. It should be narrow enough to trailer to the race for use. Your thoughts please. Thanks... Terry.