NSR Mosler friction system

3390 Views 31 Replies 18 Participants Last post by tamar.nelwan, Jan 24, 2012

JamieG

Discussion Starter · Jan 4, 2012

Last week I had a competition at my place with a friend and as usual we eventually compete with the NSR Moslers.
Usually I can beat his timing but when we raced with the Moslers he beated me and destroyed my previous record.
When he offer me to test his Moslers I took down the record half second!
We both thought we were just in our best mood.
The day after I tested it again and went down even more but I felt the motor was spinning at full revs as soon as I exit the curves without any spinning of the wheels.
Yes, the gear was loose! So I tighten it and tested the car. No way I could get near the new record! So the answer was plain, with the right friction in the gear the car could exit the curves with earlier full throttle and benefitting full torque as soon the grip between the shaft and gear was restored and that happens without wheel spinning.
I tested 1000 laps with different cars and when setting the right torque to the hex screws it works a wonder and it last for a long time!
The setting works perfectly with the Moslers with Ultragrip tyres. The cars are literally glued to the track.
I have a PWM controller but I cannot get anywhere near the benefit of this mechanical friction.

Is the above something anyone has already tested?
Is it allowed to run like this in the clubs?

Settings
Three lane track 60ft
Voltage 11V
Truspeed PWM controller
NSR Mosler AW with medium suspension springs
King 21 Evo
Ultragrip tyres
Air wheels NSR

Lap timing
Old record: 5,447s
New record: 4,986s

In conclusion, this is off course an empirical and rough system but you get fantastic results. Has anyone produced a real friction system with decent results?

Cheers,
JamieG

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JamieG

Discussion Starter · #8 · Jan 5, 2012 (Edited by Moderator)

As explained I have a PWM controller from TruSpeed which is similar to the slot.it one in terms of controls.
I do not consider myself an expert with my PWM but the effect you can reach is not comparable.
With a PWM you limit/smooth the acceleration while with a mechanical friction system you increase the revs of the motor much faster and when the gear get the grip, the motor is in the point of the curve of max torque.
The result is to have a bullet car exiting the curves with the motor screaming.

One thing you have to make sure is to have the drive train locked sideways if You do not want teeth grinding!

About posting it. Yeah I'm not a good business guy, but WTH someone will remember me in case this will be used

After all isn't this the place to post ideas and see our favorite producers will take good care of them and make it available to anyone?

Graham, good to see you in full swing. Last time I was in the forum you gave a "arrivederci" to the slot hobby. Yes it is sometime I'm not active here since I've been busy with other stuff (job and model engineering stuff).

Cheers,
JamieG

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JamieG

Discussion Starter · #9 · Jan 5, 2012

Ricko, that is also my experience but if tighten the screw with enough torque but still permitting the excessive torque to be taken in the gear you will see the result.
I recommend first oiling the bushes so in the AW the gear seat will also be lubricated.
Then I measure the correct torque keeping the the Allen key (std NSR version= long arm around 12cm) in the screw head and I rotate by hand the tyres making sure the drive is tight enough but still allow the slippery.
I find NSR ultra grip give beat result because the torque necessary to have friction is quite high. With less grippy tyres I'm not sure it will work.

Cheers,
JamieG

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JamieG

Discussion Starter · #11 · Jan 5, 2012

I agree with you that torque is from zero rpm up at a given Voltage. The decrease of torque happen when Voltage is stabilised and rpm are at the max.
The effect of controlled slip is that only when the torque starts to decrease then the gear regain full traction. At that moment you have high Voltage and high torque with the result of a bullet car.

The idea is there, now it is to find a solution to this. I've tested for few thousand laps with the Moslers and it has not deteriorate much but off course it is maybe not a 100% reliable solution. A proper friction system would do it. It is just to find it.
Cheers,
JamieG

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JamieG

Discussion Starter · #13 · Jan 5, 2012 (Edited by Moderator)

25 or 30A now I do not remember but I "guess" there is no drop there.

EDIT
DC regulated power supply 25A
Rapid PS 1525S

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JamieG

Discussion Starter · #14 · Jan 5, 2012

One detail I must point out is that controlled slip works good for twisty sections. In a club track without a twisted section maybe there will not be any benefit.
Please let me know if some of you get the same results as me.
P.S. I just file down the record with a Mosler SW to 4,971s running consistently between 5,050s to 5,200s for many hundreds of laps since the last three days without touching anything. I believe this is thanks to the quality of the hard steel employed by NSR axels.

Cheers,
JamieG

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JamieG

Discussion Starter · #17 · Jan 5, 2012

NSR King 21 Evo, the standard motor.

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JamieG

Discussion Starter · #18 · Jan 5, 2012

QUOTE (Julian_Boolean @ 5 Jan 2012, 15:49) <{POST_SNAPBACK}>It all sounds a bit Daf 33 to me, and I bet the axles look nice afterwards.

I'm not sure I understand your French but the axles are not that bad

As I said, this is rough / improper / vulgar (put it as you like) but it works at least with the torque I apply to the Allen screw. The slip is limited to few revs just at the exit of the tight bends.
A better engineered solution will avoid any damage compared to long term use of the actual set-up.
I just find it and thought to share it to see if anyone has found it before but it doesn't look like.
So I'll keep experimenting and maybe throw away a couple of axles. I think it is worth trying even if it is a "Daf 33", you never know without trying

Cheers,
JamieG

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JamieG

Discussion Starter · #20 · Jan 5, 2012

John,
it seems you got the point

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JamieG

Discussion Starter · #24 · Jan 6, 2012 (Edited by Moderator)

I feel it must be disc cups on both sides to withstand for long time. Friction discs and gears should be located on a hollow shaft with one side threaded to have a nut to register the clamping force.
Materials to be used are a question mark. I do not believe it can be anything easily subject to wear, i.e. no Aluminium or plastic, maybe Teflon.
I'm thinking spring steel for the disc cups, steel for gear and bronze for the hollow shaft and nut register.
Another issue regards he space but I am confident it can be engineered correctly.

Just for information, I found some Italian guys made friction systems some 10 years ago but when they tried to industrialize it they realize the component would have been too expensive (100,000Lire... Not £

approx 50€).

Rickxxx
Maybe you are right, I haven't found the right gear ratio even if I tried different ones. Even though I experience that having a friction give real benefits. I'm eager to know if anyone had the possibility to experience it or if it is just a Daf33 as someone mention before.
Cheers,
JamieG

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JamieG

Discussion Starter · #31 · Jan 16, 2012

Hi guys, I've been out of reach last week so I missed few posts.
I reduced the acceleration all the way down and increasing it step by step and still it cannot replicate the same effect as the "friction". I played with the different settings of the acceleration curve of the fantastic Steeve's PWM controller but still I cannot beat the 4,9... s result.

The gear ratio I have in the Mosler 1009 AW with "friction system" is the following:
- pinion 7114 AW 14 tooth
- crown 6531 AW 31 tooth
I haven't yet tried a different ratio. I'll try changing the crown (I'll see what I have available in my toolbox).

You can see here my 60 feet track. There are a couple of tight curves and there the friction enters into function. Limited effect is off course reached in all curves or when accelerating from zero speed. The torque to the grub screw is quite consistent, there is no easy slip on it.

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