In PN races over in Europe, there has been many rumors about MR-03. In Aug 09 first picture appeared on Mini-ZRacer forum.
A better picture came several days latter:
8/5/09
Evaluation of the MR-03 base on what we can see in the picture above:
From working on parts for MR02 as well as working on layout for a new chassis, where the A-arms came from, I am impressed with the MR02. It was definitely designed by someone who knows what they are doing. Things were done for a reason on the MR02. It is a very competitive chassis that has not been outdated by other aftermarket chassis. We will have to see how well this MR03 compares to MR02. The MR02 is a tough game to beat.
As mentioned on the Mini-Zracer forum, the battery is brought in further towards the center of the chassis. The two main drivers that prevents the battery from moving towards the center line for lower polar moment of inertia is the T-plate and servo motor. Both of them currently sits between the batteries. The current T-Plate on MR-02/015 has two screws lined up laterally in the chassis. The new T-Plate must be more of an "I" plate with mounting screws lined up longitudinally. That would allow the battery to move inward. Second obstacle to moving the battery inward is the steering servo motor. On the MR02, the steering motor is already standing on its side between the battery as narrow as it can be, so there is no room for battery to move in. Unless Kyosho use a smaller motor, it would have to move it forward. Between the front wheels, you can see two bumps that might be the new location for the motor. My guess is the motor is facing reverse with the motor pinion facing aft on the left side of the chassis. Then the servo gears will be on the right hand side of the chassis. That brings the drive back to the front to operate the tie rod in front of the chassis. The convenient place to put the tie rod would be forward of the front axel instead of aft of the front axel as in MR02. From the picture, it almost looks like the post on the knuckle for the tie rod is in front of the front wheel. However, placing the tie rod in front of the axel would make packaging for Ackerman steering more difficult. Ackerman steering usually have the tie rod aft of the front axel, and the width of the tie rod is shorter than the distance between the king pins. The slot on the tie rod might be shaped in such a way to facilitate some degree of ackerman steering, or MR03 may be using parallel steering. Given the typical large slip angle of the front wheels, ackerman steering may not be necessary. Only testing will tell. If Kyosho puts the tie rod aft of the front axel, there would be more ackerman steering, but then the servo motor would have to be lifted up higher in the chassis. Compromise would be a higher CG.
The top cover of the car looks to be now split in the middle. This would be good as it allows the servo gears to be cleaned out without disassembly of the rear suspension set-up. There are 3 wires coming out of the circuit board that could be either the servo or the gyro. Educated gusess would say it is for a gyro like on the 1/43 scale Dnano. Servo wires would make less sense since servo is build into the chassis and cannot be separated. The quick release for the front top cover would make it easier to install the gyro.
The motor pod in the back of the car seems to be exactly like the current MR02, but the biggest news is the A-arms in the front. You cannot tell whether is a double a-arm or a single a-arm on top with a fixed bottom like on the Radio Shack X-Mods. It does appear that there would be some camber gain in the suspension travel. That would be good as the X-Mods has no camber gain what so ever. The a-arms also acts like a rocker arm to compress the spring. The spring is placed in the empty space in the top front of the chassis. The problem with putting the spring in front of the chassis is that some car bodies may not fit. Most notable is the Porsche 962. Seems like the lever arm to compress the spring is longer than the a-arms, so the spring would have to be weaker. Is hard to tell the detail on how the spring interface with the lever arms. There would need to be an intermediate piece so as the rocker arm changes angle, the spring would not bend.
Porsche 962
The front center section of the 962 is lower than the fenders. The front slopes down quickly. The empty space in the front of the current MR02 chassis accomodate the 962. It remains to be seen whether MR03 can still use the 962 body, or if is like the AWD where some bodies do not fit. The new Sauber Mercedes body that is made for the MR03 has much more generous space in front for the springs.
We don't know yet if this is going to be the final version of the MR03 chassis or when the release date will be. Given that pictures have been leaked, it might be soon.
8/10/2009
As predicted, the T-plate is now an I-plate. There is another picture that shows the servo with a smaller size motor that allows it to be placed in the middle of the chassis. Is still inconclusive whether the lower arms move or if they are stationary. Seems like is stationary since there is no pivot for the bottom a-arm. Unless pivot is on the top side of the bottom cover plate, but that is unlikely. However, if it has a stationary a-arm like the X-mods, the the king pin should be protruding from the bottom of the chassis. But you cannot see any protrution from the bottom. There might be some other arrangement. The bottom cover is held on by 4 screws. Looks like two of them in the front is right where a pivot for the lower a-arm wants to be. It would be difficult go get a pivot in there and still be strong enough. That would argue for a static arm on the bottom. Tie rod is behind the axel. This will have good ackerman steering effect. End of tie-rod looks like is a "U" shape instead of fully capturing the steering pin. But is probably just lighting on the photograph. From this angle, tie rod does look pretty close to the knuckle. Another spy picture shows a smaller servo motor being used. That is the key. By the arrangement, servo motor looks to be still between the battery. Therefore, only the light weight plastic gears will be raised up to accomodate the tie rod. That is good since it keeps the CG low. So far this looks like a good chassis that have the potential to be better than the MR02.
10/23/2009
This is the official release date for the MR03.
Per reflexracing.net site, the MR03 has 94.41: instead of 29.34:1 ratio for the MR03. That is a huge difference. The servo motor for the MR03 is much smaller than the MR02 motor. However, the MR03 motor is a coreless design. This means the wires do not wrap around an iron core. There is no detent to the motor. You can spin it freely with the hand. Coreless motor spins faster and have lower inertia that the cored motor. However, this motor would have to spin 3 times faster to match MR02 steering speed. The MR02 steering speed is just about as fast as anyone can humanly turn the steering wheel.
Test with the MR03 and MR02 side by side shows the MR03 to be actually slower than the MR02. It is smoother and more accurate however. This could be due to the fact that per reflexracing's site, MR03 has 87 steps increment than 59 steps for the servo. Therefore, the MR03 turns in increment of about .7 degrees instead of every 1 degree.
One thing to note on the MR03 is that the kingpin on it was highly polished, and the knuckle bore was nicely fiinshed as well. Therefore, when new, there is no stiction for the suspension. Reports from user is that as parts wear and get dirty, there is stiction on the suspension.