new rjr 16d arm

[delboy]

Hi Monty
there has been much talk elsewhere on the board concerning the new larger diameter RJR 16D arm. Have you tried them yet, and if so, would be interested to know your comments.

[Monty @ B.O.W.]

Del,
I've balanced a few (seem normal enough there) but I haven't run any. They won't be legal in my region until January 1, so I'm not feeling pressured. I also haven't seen any go fast yet, but this is understandable since they will definitely be using different setup parameters from those we have been accustomed to.

At this time, I'm skeptical as to how good they can get. In theory, larger motors can produce more total power. On the other hand, slower turning motors don't cool as well, and the car will often not handle as well due to lack of gyroscopic action. Time will tell. I'm plenty willing to switch, if I HAVE to....

[Robert Root]

Monty

As you said TIME WILL TELL

I am surprised that you gave am opinion being you have not tested them yet.
This armature is so different in design your basic assumptions do not apply.
We ran a 14 tooth pinion on these arms. on a 200 foot track and they ran cooler than the standard arm. with a 8 to 10 tooth pinion.
There is a better balance of torque to rpm and they have better brakes. Racers that have tried them said they have to back down there brake control. These arms. stop like wing cars and you do not have to roll into the corners. Theory means nothing to a racer its who gets around the track the fastest.

RJR

[Tom Marsteller]

Axle,

My fastest motors at CFR were not the ones with the strongest magnets. They were about 10% softer than my strongest magnets. (gaussed about 932 in the can vs. 1082 for my strongest magnets.)

Before Rick and Scott rewired the King, My fastest GTP used SMQ magnets which were about the softest I have ever used. The track voltage at that time was 12.7 volts. After it was rewired and the additional power sources added the track was about 13.9 volts and I had to use stronger magnets.

Too soft a magnet usually produces a hotter running temperature motor with less brakes.

Too strong a magnet usually produces a motor that just does not seem to unwind (rev).

Finding the proper balance of magnet strength, armature timing and gear ratio for the track you are racing will optimize your cars performance.

Where the new RJR 16-D armatures might really shine will be in the new Kelly setup which I am guessing will not contain the magnetic field as well as the Rotor and the Twister setups.

Jay Kisling tried the new RJR arm at Pit Stop's Dash for Cash. During Fridays practice, Jay was in the 4.6's using a JK Scorpion 3 and was also using either a 13 or 14 (64 pitch) tooth pinion.

The arms metered good but not lower than anything else (around .064 ohms).

They way I see it for now is that this new armature is another option on how to build up a motor for a given track.

On My home track with 14.1 volts the RJR was faster. It had a more tractable (driveable) powerband.

I remember watching Ron Hershman come to a race with about 50 motors once and tried them all. He found the fastest for that race and used them. He said that on some tracks they were dogs.

I think the most misleading situation that happens when using the new RJR arms is how much less current they draw during break in.

Finding the proper combination for a given race voltage is the key. Some tracks are tricky as they have a "surface voltage" and a race voltage.

See you soon and good luck at Dan's for the ISRA warmup.

Tom......

[RocketRod]

Brakes also change with the magnet strength. So you have to find the balance for your driving style.

[loosenuts77]

I don't know how much this helps but,

i threw a new rjr super arm in an old rotor set up and it ran pretty quick. the car is a gtp with a bmw body. a good time on this track is a 4.6. With this car i ran a 4.4 my first try.my only problem was brakes. i had my controller settings almost all the way off and the car still had full brakes. i had it geared at a 10-40, but i think im going to change it to a 11-40. The track is a 185' custom track in town(rebel raceway) i think once i can get the breaks under contrill i will be able to get a 4.2 out of it.

so, I like the new rjr arm. and it didnt run as hot as my parma or proslot supers. However, being new to rjr, i didnt realise the arm was hemi wound. it pulled 4 amps a long time, lol.