Comments on latest version:
Is power curve compatible with wheel speed and power needed for both acceleration and top end? Wankels notorious for gutless low end. If it won?t accelerate from 50 mph, probably won?t get to 500.
Good luck push-starting 7 independent and rotationally uncoordinated IC engines.
With 5 axles, wheel load distribution is all over the place and variable. Tail wheel detracts from power wheel traction.
Very wobbly chassis in lateral and torsional motion at two-rotor location.
Steering so close to main power wheels gives little leverage or fine control. Steering will be fighting the tail wheel as well as trying to side-slip the power wheels.
Assuming there is a CV joint of some sort in the steering upright member. Otherwise kinematically incompatible with suspension movement. In any case, suspension movement induces lateral movement of the contact patch. Probably unsettling for driver.
Rear aero yaw ?control? a bad idea. Also induces roll.
Braking capability appears to be far in excess of what can be put to the ground through one alloy wheel.
Hi IO,
Thanks for all the identified issues...exactly what I'm looking for from the forum. I'll address my thinking on these items as follows:
For clarification, the 7 rotors are combined in the following groupings: (1) three rotor engine; (1) two rotor engine; and (2) one rotor engines for a total of 4 powerplants driving 6 wheels. The 7th trailing wheel is not powered.
Power curve: The 23.5 diameter aluminum wheels turn 8582 rpm @ 600 mph (7152 rpm @ 500 mph). Consequently the direct drive engines turn the same rpm as the wheels for all speeds. Since salt traction is at a premium, running a low torque powertrain with a lot of contact patch would seem idea if power increases significantly with rpm up to the distance limit. I would imagine the ideal power curve would allow max rpm to hit at the max distance. The power curve question you posed IO depends on mass, drag, and traction between 0 mph and whatever rpm is achievable by the 5 mile marker.
I'd say we'd need a push truck with gearing and torque to hit 150 max speed by the 1/2 mile mark. That's 2145 rpm on the engines where I believe the power curve would begin to kick in relative to vehicle mass. Dropping total weight down between 3000 to 3500 lbs would go a long way toward a desirable acceleration rate. BTW... what's the push distance limit?
Push starting: I personally don't see a problem push starting the 4 engines. With zero slippage, all 6 wheels in contact with the track surface will be turning the same rpm when the ignition is lit. The 3 and 2 rotor engines will each use a common crank/axle so those rotors will be rotational indexed to fire in the proper sequence. The 2 single rotor engines will run independently but throttle matched to the 2 and 3 rotor engines. Only when wheel slippage occurs will we see a disparity between engine rpm(s) but common ramp settings across the throttle bodies should compensate to bring that back in line within some acceptable range. At this time I have no idea what that would be.
Wheel load distribution: The two steering wheels are sprung so the 3 fixed axles will be most affected by load distribution. On a perfectly flat surface loads would be balanced relative to Cg for all wheels I believe. From appearances I think the Cg will be close to the axle centerline of the 3 rotor engine. Depending on chassis flex effective load on the trailing wheel will be a non-issue traction wise to the forward power wheels.
Wobbly chassis: I agree with your comment here. I've included a drawing showing added reinforcements to that section of the chassis.
Steering: I think there's an advantage here from the two inline steering wheels. The angular distance between the lead steering wheels and the fixed wheels offers a slight benefit over a single steering wheel or a pair of side spaced wheels. I've also been told its beneficial to slow the steering way down on these cars over what we might otherwise think it should be, so effectively we're getting that here with this arrangement.
I see your point about the steering wheels fighting the trailing wheel with the fix wheels in between. We could use a center swivel for the trailing wheel much like the tail wheel of a tail dragger airplane. It would then be easy enough to add sprung suspension for that trailing wheel.
CV Joint: Yes indeed there are CV joints drawn within the steering spindles. The upper and lower arms that center the spindle hinge in alignment to one another such that there is no camber change throughout the suspension movement. Because the spindle center is aligned with the center of the wheel there is zero scrub angle as well.
Rear Aero Yaw control: I remember posing this question a while back, thanks for responding. I have no such controls draw into this design.
Braking Capability: Yes, I recognized that too so I'd say this is a redundancy rather than a necessity.
Thanks IO... Terry.