It was like Christmas morning when the Fed-Ex truck pulled up to deliver my review samples of the new AFX Mega-G. After hearing all the hype, the reports from iHobby and the infinite postings at Slot Car Illustrated and other hobby sites, I couldn’t help but to keep myself guarded in case there was a let down. So I opened the box….
Wow! The first impression left me with one word….Wow! I could even say it backwards….Wow! I was feeling the rush and couldn’t wait to open the packaging and get this awesome looking car on the track and turning laps. But the writer thankfully took over and I remembered that I needed to take pictures of the packaging for this article. So let’s get started, the anticipation is killing me!
Packaging
The cars come wrapped in a clam shell package we have all become familiar with. The AFX logo emblazoned on the front with the menacing “MEGA-G” logo that just screams you are going to go fast with this car. The car is nicely secured to a plastic insert and my samples had one wire that held it all in place. Kudos for that! I know that items have to be secured in the packages in this day and age, but I dread my kids’ birthdays and Christmas gifts every year. Not because I feel older, but having to perform the surgical extraction of 2 dozen wires and straps wrapped around the items they just received. But back to the Mega Gs. The cars were flawless and showed no signs of package wear or breakage. It’s show time now, let’s get the package open, the cars out and see what they can do.
Body and Appearance
I received two of the Champ Car designs. They share the same body with very elaborate paint schemes. From here on I will refer to them as the “white car” and the “green car” to describe the processes and test results.
The Mega-G has to be one of the most unique chassis designs in dimension I have seen in quite some time. Because of the narrow proportions, the body artists were able to present a beautiful scale design that captures the intricate lines of the open wheel car. From the ground effects to the wing structure, the detail is incredible. The chassis and body also act together to enhance the appearance. The lower front portion of the chassis is molded to show off a pair of lower “A” arms around the front axle. The details of the sculpture, vented areas and wing struts are extremely fine and crisp. The paint is equally remarkable. The multiple passes of color in the build up process must be a chore to accomplish, but the results are eye popping. Even the smallest details, down to the drivers lap belt buckles are clearly visible. My only complaint, and it’s minor, is the driver’s head/helmet. It looks like a full face unit, but the transition from the helmet to driver’s suit is blended in and appears to be one solid piece. But I can live with that! The extreme detail on the rest of the car makes up for that and far more.
They look like they are moving 200 MPH just sitting on the track.
The body appears to be made of a lightweight ABS based plastic. It is very rigid and very strong. Both of the samples took some serious slams into retaining walls during the testing phase and neither lost a single wing or part. The body weighs in at a mere 3.6 grams, almost a full gram lighter than the tyco March body pictured elsewhere in this article.
The bodies mount to the chassis with a tab and slot design similar to the original G+ F-1 cars of the 70’s and 80’s. The tab is located on the body and the slot on the chassis. The detail of the body design even goes under the car! The ground effects area wraps under the body and back up to the mounting tabs. The mounts and wheelbase are unique to this design, so none of the existing bodies will interchange, but AFX has said that will not be the case with the next version of this chassis using a standard wheelbase length. There is no wasted space between the body and chassis. The body lines also incorporate a pocket for the crown gear so the stance is even lower and more realistic.
The bodies fit tightly with no slop in the mounting points and are easily removed for maintenance access.
Observations and Opinion:
The bodies are clean, light and well made. The fit and finish are extremely nice. The detail is beyond excellent. Parts that are normally fragile, like the front and rear wings, are strategically attached keeping the appearance of the 1:1 car, but are quite strong and resist easy breakage. The body has extremely close tolerance in its clearance on the track surface and makes it look even lower and faster.
All of the logos and paint lines on my samples were simply perfect.
Chassis
The chassis is made from a nylon based plastic and holds it’s shape well, even after an impact. Once again there was no wasted space in the design. Once stripped of all the component parts, the bare chassis looks like fine lace in how it is structured. By design there are no gaps or extra space between the component pieces which add to the support of the chassis as a whole. The chassis measures 2-3/16th inches long and 11/16ths inches wide and only sits 1/2 inch high. The assembled chassis weighs in at 13.1 grams. The highest point in the assembled chassis is the armature. This car has an incredibly low center of gravity. There are even specific cut-outs in the chassis for the crown gear, to reduce the overhang in the rear of the chassis. The body mounts are recesses that tabs on the body snap in to. In stock form the chassis has 0.10 inch clearance above the track rails. The guide pin clip is also reduced to its minimal requirement and holds the pin nice and tight. The guide pin location is slightly farther back than most designs due to the forward front axle location and should aid in handling on tight radius corners. The front axles have one fixed, closed loop position creating a wheelbase of 1.7 inches. The items I will identify as the front and rear bulkheads are more akin to spacers and retainers than actual bulkheads if compared to other traditional designs like the Tyco X-2. The “bulkheads” do not contain any mount points for brush tubes or armature bushings. These units on the Mega-G act as motor magnet retainers and the rear has the additional duty of holding the traction magnets to a fixed height. The actual bulkhead assembly is molded into the main chassis. Brush tubes and armature bushings are held in these molded slots.
Here are some additional views of the details and dimensions of the AFX Mega-G chassis. Incredibly narrow, this chassis will become an ideal platform for many themes in motor sports that were unreachable with previous designs. The top image shows just low you can go and still make a performance oriented chassis. Notice the notch in the rear of the chassis to accommodate the crown gear. AFX squeezed as much performance as they could in a very tight operational space.
Magnets
Motor Magnets
The motor magnets are polymer units. They are concave on the armature facing side with a flat edge facing the chassis. The top and bottom are tabbed and slide into position in slots in the chassis with the “bulkheads” keeping them in place. The magnets slip in after the armature is in place and the bulkheads snap in to retain them in position. It is a bit tricky to do the first time but is very easy to work with. The air gap to the armature is .020 inches. There are no additional shims or flux collectors on the stock unit. Next we will measure the strength of the magnets. I will be using the formula B=1000*(V0-V1)/k, where B= Gauss, V0 is the calibrated measure (supplied by the manufacturer) for the Hall device sensor (magnetic sensor), V1 is the measured value read from the magnet and k is the sensitivity (supplied by the manufacturer) of the Hall Device (magnetic sensor). In simple terms, the Hall device restricts or increases voltage when a magnet is near it. By measuring the voltage change you can use the formula to determine the gauss strength. I built my own device for about $20.00. It is fairly accurate and gives excellent comparative numbers. This is how I determined the strength of the motor and traction magnets. I will use this same method in future reviews so you can compare the strengths from the same testing process, apple to apples so to speak. The Mega-G motor magnets measured 0.06 voltage decrease on the North Pole of the magnets and a .4.74 voltage increase on the South Pole. This translates to an approximate 1000 Gauss strength.
Traction Magnets
There are 2 traction magnets and they are made from neodymium. They are located in the typical area of the chassis just in front of the rear wheel location. They are located exactly 1/2 over the track rail, running the length of the magnet itself. These units are press fit into the slots from the top of the chassis. They are held in place with the main chassis and rear bulkhead. The air gap to the track rail (using Tomy/AFX track) was .020 inches. The chassis has a molded frame around the traction magnets that is close to 0.10 inches thick adding to the space between the traction magnets and the rails. These magnets were very strong and compared well to after-market units. Using the same method as the motor magnets, the traction magnets measured at 450 gauss on both the North and South Poles. The extra spacing did not prove to be of any issue to the performance.
Axles/Rims/Tires
Axles
The front axle is a solid unit made from steel. There is no independent rotation of the front wheels, this is a single bar axle. The front axle is .047 inches in diameter and 1 1/4th inches long with rims and tires.
The rear axle is a solid unit made from steel. They have the cross cut, diamond pattern on the ends to help retain the rims. The crown gear and pinion retainer are pushed onto a spline section, slightly off-center on the axle. Due to the location of the spline section, the rear axle will only fit into the chassis (remember the notch for the crown gear?) one way. The rear axle is .059 inches in diameter and 1 1/4th inches long with tires and rims. This gives you a full 1/16th of an inch to work with and still fall under most rule sets. The car in stock form easily passes through a tech block.
Both axles were true and straight, even after removing the rims. The axle holes pass through the entire rim, so a standard rim remover or press would work fine with these parts.
Rims/Hubs
The front rims are 7-spoke units, either chromed or black plastic on the samples I received. They are press on type and do not rotate independently. The front rims are .275 inch in diameter. The rear rims are also 7 spoke units, either chrome or black plastic. They are the press on type. The rear rims are also .275 in diameter. All rims were true and round, no flat spots or odd shapes. The rear rims did have a mold mark, but did not cause any distortion of the tires and would be easily removed. The possibility of the rear rims stripping from the knurls on the axle is a concern. Both rims are flanged on the inside for tire retention/position.
Tires
The front tires are a fairly stiff/hard rubber compound. The tire’s outside diameter is .375 inches. The tires were true and had no flat spots or flashing. The rear tires are a bit softer than the front. The rear tire’s diameter is .455 inches. The tires were true and had no flat spots or flashing.
The rear tires have a excellent grip for stock tires. Silicones or some sili-spongies would of course improve the grip considerably. The front tires are wonderfully scaled and match up well to enhance the appearance of the open wheel car. The tire detail is incredible with a clearly stenciled “Bridgestone Potenza” logo on each wheel. Try as I might, I could not rub the lettering off in normal activity or handling of the car. I can see these tires popping up on a whole host of customs projects. Maybe we can see some Firestone’s or Goodyear’s in the future?
Bushings and Bearings
The AFX Mega-G uses brass type bearing on the front and rear of the armature shafts. These appear very smooth and allows for the armature to spin very freely. After removing the rear axle assembly and motor magnets, the armature spins quite freely and for a considerable duration. Very little friction is displayed. The brass bushings are snapped in place in the main chassis . The front and rear axles have no separate bushings or bearings but rely on the chassis material to ride through. These were also very smooth for this type of design.
Gears
The crown gear is a 25 tooth gear, standard pitch (SAE). The material appears to be delrin or similar plastic. It is fairly rigid and the teeth are well defined. It sets well on the rear axle and has a separate retainer/spacer for pinion mesh.
The pinion gear is a 7 tooth gear, standard pitch (SAE). The material appears to be the same as the crown. The pinion also has a spacing nipple that rides along the crown spacer. The gear fits tightly on the armature shaft and shows no sign of slipping.
The gears mesh extremely well. In box stock form, it was very smooth. There is no sign of skipping or slippage. The spacer/retainer holds the pinion in place and shows minimal friction on the pinion gear.
Electrical System
The brush tubes are brass units. They are snap fit into the molded retainers on the chassis. The brush springs are high tension coil units. They appear to be very stout and would be less likely to compress under heat. The wire measures approximately .008 inches and is just shy of .25 inches long.
The brushes are a silver compound and of a medium hardness. They came with the armature facing side shaped to the comm and a nipple to help keep them centered on the brush spring. They are approximately 3/16ths inch long.
Pick Up Shoes and Springs
The pickup shoes are stainless steel and thin. The material is harder than copper and will retain its shape longer. They can be picked up by a magnet, so be careful when you remove these. The tail of the pickups wrap around the brush barrel. The shoes are longer than most traditional units, making up for the extended wheel base of the chassis. The pick up shoes on the samples I received needed absolutely no adjustments. The long flat step rode squarely on the rail, the entire length of the step. Wear patterns show as being evenly applied to the whole shoe, indicating ideal contact area and weigh distribution.
The Pickup springs are coiled units and final production units will be made of phosphorous bronze. The springs ride securely in a molded cup on the underside of the chassis. The suspension is firm but not bouncy.
Armature
The armature is a standard 3-pole arm with 14 laminations. The wire appears to be 37.5 gauge. My two samples measured at 6.0 Ohms per pole (Green Car) and 6.8 Ohms per pole (White Car). After speaking with AFX, they assured me the production tolerances for the armature would be 5.9 to 6.0 Ohms per pole. The laminations are straight in design and my samples appear to be dynamically balanced. Each pole’s laminations, in different areas and amounts, were reduced or lightened. On my static balance jig, both samples came up perfectly balanced no matter which pole I placed in the upright position. Sources at AFX confirmed that no balancing was done, but they are seeing their samples all coming into production pretty well balanced. A nice problem to have! The commutator is copper bonded to phenolic. The timing of the comm. Is 0 degrees, tap dead-center on the White Car and is 2 degrees clockwise on the Green Car. The armature wire is folded securely onto tabs.
Fit and Finish
The overall fit and finish of my two samples were excellent. The pickup shoes needed no adjusting to ride properly on the rail. I’m not too keen on the cross-cut knurls on the rear axle. They will eventually wear the rim/hub down until glue will be required, depending on how often you need or want to remove the rear rims. The gear mesh was very smooth out of the box and all parts were lubricated well. The bodies were extremely well made, light and the paint and finish were excellent.
I could not get over how well designed and how low the bodies on the two samples were. I captured the idea of how low that is in the pictures below. The orange Tyco March body was modified and placed on an Aurora Super Magna-Traction chassis. It is the lowest setting car I own. The AFX Mega-G, straight out of the box is almost as low. I believe it’s only shy a couple of thousandths of an inch to be lower. I also placed an Aurora Williams Saudia car in the shot to give an additional comparison.
Performance Testing
Break-In Period
There are four phases to the break in process:
1.) First, the cars will be run at 6 volts/3 amps, rear axle assembly in place but free-wheeling, no load, for 5 minutes.
2.) After the first run, the cars will disassembled and all parts examined to determine any abnormal wear.
3.) The cars will be cleaned, re-assembled, adjusted where needed, lubricated and run in for another 5
minutes at 6volts/3amps.
4.) If no issues show, the cars will proceed to the remaining tests. Otherwise, repairs or adjustments will be
made until the cars can complete the remaining tests or be retired from the review.
Observations
Both cars were placed upside down and the power connected to the pickups with clips. The voltage was dialed to 6 volts. The Green Car drew 1.5 amps on start and dropped down to .4 amp. The White Car drew fewer amps at 1.3 on start and settled down to .35 amp.
Both cars ran their 5 minutes break-in session and were completely disassembled. All parts were cleaned and examined for excessive wear or other problems. Neither car showed any issues.
I reassembled both cars, lubricated them and ran them again for 5 minutes at 6 volts/3 amps. No issues came up in the second running. Gear mesh was clean and quiet. Motor brushes were normal in wear patterns and pick up shoes were flush to the rails making full contact across the length of the step in the pick up shoe. There was no arcing or other power issues from the electrical components.
Now the cars are ready for performance tests.
Acceleration Tests
The acceleration test is ran on a 25 foot straight strip, made from Tomy AFX track. The track is painted with Acetone based paint. All rails are level and are set at .015 inch above the plastic surface. Power is available in 2 forms, an AC to DC converter at 19.8 Volts and 3.5 Amps or DC Battery Power, either 12 or 18 Volts at 125 Amps. All acceleration tests will be ran from each power source. The cars will be controlled by a single pole switch to full power. The first 15 feet of track is powered, the last 10 feet is dead section. The dead section can be wired for coast or dynamic braking. There will be sensors placed at the beginning of the strip and at the 15 ft. mark. An electronic timer will engage at the tripping of the first sensor and stopped at the tripping of the 2nd sensor. Times will be measured in .000 thousandths of a second. Five passes for each power option will be made and averaged for each power option. I will set these results in comparison to a box stock Tomy AFX Super G+ (1st Generation) car as the baseline and the last car tested, in this case an Auto World Super III.
| White Car | Green Car | |||
|---|---|---|---|---|
| 19.8 Volts/3.5 Amps | 2.405 Seconds | 19.8 Volts/3.5 Amps | 2.225 Seconds | |
| Battery Power 12 Volts/125 Amps | 2.854 Seconds | Battery Power 12 Volts/125 Amps | 2.988 Seconds | |
| Battery Power 18 Volts/125Amps | 2.387 Seconds | Battery Power 18 Volts/125Amps | 2.129 Seconds |
Braking Tests
The braking test is ran on a 25 foot straight strip, made from Tomy AFX track. The track is painted with Acetone based paint. All rails are level and are set at .015 inch above the plastic surface. Power is available in 2 forms, an AC to DC converter at 19.8 Volts and 3.5 Amps or DC Battery Power, either 12 or 18 Volts at 125 Amps. All acceleration tests will be ran from each power source. The cars will be controlled by a single pole switch to full power. The first 15 feet of track is powered, the last 10 feet is dead section. The dead section can be wired for coast or dynamic braking. There will be sensors placed at the beginning of the dead section and the track marked in inches starting at the dead strip. An electronic timer will engage at the tripping of the first sensor. Times will be measured in .000 thousandths of a second and recorded by sight when the car stops completely. Five passes for each power option will be made and averaged for each power option and for each braking option.
| White Car Coasting Stop | Seconds to Stop | Distance to Stop | Green Car Coasting Stop | Seconds to Stop | Distance to Stop | |
|---|---|---|---|---|---|---|
| 19.8 Volts/3.5 Amps | .070 Seconds | 23.25 Inches | 19.8 Volts/3.5 Amps | .071 Seconds | 24.1″ Inches | |
| Battery Power 12 Volts/125 Amps | .065 Seconds | 21.5 Inches | Battery Power 12 Volts/125 Amps | .066 Seconds | 22.0 Inches | |
| Battery Power 18 Volts/125Amps | .084 Seconds | 26.75 Inches | Battery Power 18 Volts/125Amps | .085 Seconds | 27.1 Inches |
| White Car Dynamic Braking | Seconds to Stop | Distance to Stop | Green Car Dynamic Braking | Seconds to Stop | Distance to Stop | |
|---|---|---|---|---|---|---|
| 19.8 Volts/3.5 Amps | .020 Seconds | 3.1 Inches | 19.8 Volts/3.5 Amps | .022 Seconds | 3.4 Inches | |
| Battery Power 12 Volts/125 Amps | .009 Seconds | 2.9 Inches | Battery Power 12 Volts/125 Amps | .010 Seconds | 2.9 Inches | |
| Battery Power 18 Volts/125Amps | .025 Seconds | 3.5 Inches | Battery Power 18 Volts/125Amps | .024 Seconds | 3.4 Inches |
Cornering Tests
The cornering test is run on a 9 inch radius circle, made from Tomy AFX track. The track is painted with Acetone based paint. All rails are level and are set at .015 inch above the plastic surface. Power is available in 2 forms, an AC to DC converter at 19.8 Volts and 3.5 Amps or DC Battery Power, either 12 or 18 Volts at 125 Amps. All cornering tests will be run from each power source. The cars will be controlled by a measured dial that ranges from 0 to full power and is incrementally marked. Cars will be placed on the inside lane and be accelerated in marked increments until they spin out or de-slot. The power in volts/amps will be recorded at the breaking point. Five passes for each power option will be made and averaged for each power option.
| White Car | Volts to Deslot | Green Car | Volts to Deslot | |
|---|---|---|---|---|
| 19.8 Volts/3.5 Amps | 14.7 Volts | 19.8 Volts/3.5 Amps | 14.4 Volts | |
| Battery Power 12 Volts/125 Amps | 10.7 Volts | Battery Power 12 Volts/125 Amps | 10.9 Volts | |
| Battery Power 18 Volts/125Amps | 13.5 Volts | Battery Power 18 Volts/125Amps | 13.4 Volts |
Overall Conclusions
This new offering from AFX is stupendous! The performance rates this design very high and has unlimited potential as a one of the best efforts put forth in slot racing from the mass market. The low center of gravity, the extended wheel base and tire compound all combine to offer a truly enjoyable experience right out of the box. Both cars accelerated well. The Green Car with the 6.0 armature really performed under the higher amp power source. Both cars coasted a bit further than I expected. I’m accounting that to the extra smooth gearing and armature bushings. Dynamic braking was quick to respond and the quick stopping is witness to the strength of the magnets and the relative closeness to the armature surface. I was somewhat surprised at the handling characteristics. Although the Mega-G’s out performed previous models tested, I was expecting a bit more due to the lower center of gravity and the lightweight bodies. There is still room for fine tuning, so I’m certain this can be adjusted for even better results than I record here. They did perform exceptionally well and although not included in my battery of tests, the Mega-G now holds the 1 minute and 5 minute lap records for box stock on both of my tracks.
The pick up shoes are wonderful. Right out of the box they are ready to run and did not require any fiddling on my part. The springs have just the right amount of firmness to keep the shoes planted on the track rails, but soft enough to not cause any bounce from the front end. I did not see any excessive brush wear, even after 2 hours of run time. The cars performed well on my 54 foot road course and the 44 foot oval. Handling was predictable and after a few laps, I was able to really dive into the tightest of turns without fear of de-slotting or spinning out. The rims and tires are true, round and ran perfectly on both cars. The grip was excellent for a stock tire and the side stencils are incredible.
Things I like to see improve:
- 1.) Adjustable wheelbase. AFX purposely made the wheelbase fixed for the appearance of the Champ Car bodies. They did an outstanding job of this! I would like to see a future chassis that would have 3 or 4 wheelbase positions. According to sources at AFX, the next Mega-G chassis will have the standard wheelbase length.
- 2.) Cleaner rims. Reduce the mold marks left from the parts tree.
- 3.) Love the Bridgestone tires! Maybe Goodyear, Pirelli or Firestone next? Even Toyo for the tuners?
- 4.) White bodies. This would be the customizer’s dream to have a Plain Jane, undecorated body to detail without having to strip or sand. (Every manufacturer, not just AFX needs to do this.)
Things that are right on the money:
Everything! Period. From appearance to performance I could not find anything that would keep me from
buying a stable full of these stallions! The detail from the tires to the tips of the wings are right there and on the money! As these proliferate the racing programs across the HO world, I can see racers and the after-market offerings increasing the already terrific performance, even higher.
AFX really hit a grand slam here. The Mega-G is the whole package. The body and tire detail are a sight to behold in this scale. AFX took what they learned with the Ford GT40 and built a high performance chassis to compliment the beauty of the Champ Car body design. I look forward to seeing what other elements they add to this new concept, with the addition of the standard 1.5 inch wheelbase. The narrow design of the chassis will allow for a range of scale representations of cars we could not create before. Formula-1, historic Indy or those really low slung GT cars are all possibilities now that a platform exists that can house a such low and lean machines. As the heir apparent to the Super G+ throne, the Mega-G will be leaving its mark on tracks everywhere.
Drivers…Start your engines!