As stated in an earlier article I went looking for some information on Aurora armatures only to find that the Front Range HO website could not be found. I had saved that information several years back. It took some time to find it but I did. That said here is some great information on AFX armatures courtesy of Front Range HO. If you are interested in this info then click the read more link.
OHM Range: 6.0 - 7.5
Green Wire with Red Tips
The Tuff Ones also introduced the 14t Cluster Pinion which was carried over to AFX chassis throughout their production run. These arms produced a fairly good mix of top speed and low end torque; and when run on 20V with the proper amperage these can really come alive. The early Tuff Ones arms had copper colored wire with later models having green. To the best of our knowledge, only the green wire version made it into the AFX. Aurora decided to re-introduce the (Copper|Red) color combination on most of the AFX magna-traction (MT) cars throughout their production runs.
Use an ohm meter as your guide, as you don't want to confuse the earlier (Copper|Red) Tuff Ones armatures with the latter, lower performing (Copper|Red) magna-traction arms.
OHM Range: 13.0 - 15.0
Copper Wire with Red Tips
As previously mentioned, don't confuse this arm with the similarly colored but lower better performing Tuff Ones arm.
An unusual version of this armature was available in European A|FX magna-tractions. This version had a printed circuit type commutator that sported a resistor or capacitor on each pole. It was suggested by Jim Sgrignioli of Yellow Jacket Performance that this was due to Europe's power not being as clean as U.S. & Canadian power. Cars equipped with this armature might also be found with a capacitor soldered between the pickup shoes, probably to even out the A.C. voltage ripple and prevent surge damage.
OHM Range: 6.0 - 6.5
Green or copper Wire with Green Tips
Usually available as a separate item through American Line NOS (Copper|Green), this arm, when properly balanced, can attain very high speeds but is best suited for lighter weight cars T chassis due to it's torque profile; cars that have been lightened or use lighter bodies (like Cheetahs, Falcons, Lola's, GT40's or some of the lighter aftermarket resin racing bodies) benefit most from this arm.
If using weighted rear wheels, avoid using ones too heavy if road racing on technical tracks requiring you to dramatically slow down and speed up repeatedly (like a track with many 6" curves). Complete NOS AFX gearplates from American Line containing the Green|Green version are still available and it is widely thought that they contain the genuine Aurora parts.
OHM Range: 14.5 - 15.4
Red Wire with Red Tips
Whether intentional or not, the 4 Green (I think you meant Red?) Devil arms we've inspected all have the communtator plate slightly rotated counter-clockwise by 2-4 degrees (if viewed from bottom) leading to a slightly retarded timing curve, suggesting higher top end. This better than average arm can perform well when matched with either AFX Super II or Johnny Lightning magnets and a 14t cluster pinion.
OHM Range: 7.0 - 7.5
Copper or Green Wire with Blue Tips
Heavier gauge wire was used, so this arm tends to run hot. Stronger magnets and chassis or body colling considerations are a must if used for Enduro Road Racing. this arm can typically be used in heav customs or performance projects using weights or weight pans. apopular application is in HO Drag Racing, since the main characteristic is low end torque.
When road racing, this arm will launch your from a dead stop, but others will soon be pasing you due to its lack of top speed. You might consider it for road racing when on a very technical (lots of turns) track since it can really barrel out of a turn. You should realize that the A|FX specialty chassis this arm was found in came with large diameter wheels, with dragster tires having an O.D. of .500 (half an inch), so even though this arm typically isn't capable of high RPM, the taller tire provided the higher top end speed. If you are going to road race this arm, check our gearing discussion and consider going to a taller gearing profile to compensate for its lack of all-our RPM.
OHM Range: 4.0 - 4.5
Copper Wire with Black Tips
Initially available in the early 1970's on the ill-fated and under-rated AFX Super II car, which also came with a special edition Aurora Black Chassis out-fitted with brush cups, chassis weights and unique armature gear plate, braided shoes and special guide pin straight from the factory.
The armature as Aurora produced it also sported a "double-wire wind", speial advance curve and had a special silver-plated commutator plate; all for $12 - $13 at the time! No longer in available as NOS, they still pop-up used on eBay every once in a while with complete cars going for around $200-$400.
A variant of this armature was used in the XLerator cars. Precision replicas of this armature are available via AG&G Hobby.
The Quadralam, built for the long straights!