RC12 L3 Servo Mounting?

[Oliver]

Looking at this months RRCi I saw a photo of Paul Ash's car from the 1st National. From the picture it looked like the servo was mounted flat on the chassis, and not at an angle (as is standard).

I also remeber seeing this tried out a while ago (possibly Spashett/Cyrul at Cleveland a couple of years back with the Trinitys).

Basically, what difference will this make to the car's handelling (in comparison to the "standard" mounting).

Many thanks
Oliver

[Russ]

I have no experience of this personally but I have seen this on an american site:-

1 - It keeps the weight and overall center of gravity as low as possible.
2 - The car is a little lighter not running servo mounts
3 - It's much easier to adjust ackerman by changing the servo horn ball studs sizes. When the servo is mounted on an angle, it is way too complex to understand the ackerman changes.
4 - The flat setup also works well with the mid-size kimbrough servo saver. It is much stronger then the small grey or red mini size.

I hope this helps

[mark barord]

The main advantage from mounting the servo flat on the chassis is that you have a nice flat, perpendicular to the chassis, surface that lets you mount the reciever on it's side behind the servo and this frees up room to mount the transponder on the chassis. I used to run like this but I could never completly get rid of bump steer.
I would go with the normal mounts.

[PDW]

I've run both on a Trinity car. The flat servo does give me a bit more bite to the steering right through the corner, and I prefer it that way. I, too, couldn't get rid of the bump steer; it has been ignored!!

However; this is on a Trinity car and I am not sure what the effect will be on an RC12 - try it and see, as it is completely reversible if you don't like it.

[PUASHP]

Oliver,

As it was on my car that you have noticed the servo mounting position let me explain my reasons.

The servo is actually mounted on some 3mm spacers to raise it clear of the chassis. It is also mounted 7mm further forward than the kit holes in the chassis.

This moves the servo weight lower down and further forward, and saves some weight overall on the car. I run 2 thin washers behind the ball studs to get the correct ackerman, but this is something I played around with until I got the correct feel in the car. Its all about how the car feels mid corner and more ackerman will make it feel smoother throughout the turn.

With such limited suspension movement bump steer is nothing to worry about on a 1/12th car.

Additionally, having broken a few servo cases in heavy shunts, fixing the servo this way is safer I feel and I have yet to break a case even after a major impact.

I hope this is of interst

Cheers


Paul

[Oliver]

Many thanks for all the info.

Definatly something to think about ...

Oliver

[Pro_3_racer]

hey guys

after looking at this thread im thinking of runing my servo like this, as i run a stander servo i could od with the extra space etc, but the only thing is how do you fix the servo to the chassis, as i cna see you can use servo tape but after a bid crash etc wouldnt the servo move etc.

or is this hoe you do it lol

hope you can help

Michael

[PDW]

Michael,

It is possible to turn the Trinity mounts around, so the upright side faces the front. You might be able to do this with your mounts too. Remove the servo and turn the mounts through 180 degrees. Check that the servo is now in a good position relative to the steering arms - not too far back or forward. If you can't replicate the old angle of the arms, you will have to re-drill holes in the bottom of the mounts to move them to the correct position.

Place the servo in a position where the saver clears the chassis and drill two new holes for the screws on the faces of the mounts. Fit the servo with screws and washers as before, and reset the steering links to give whatever toe in/out you need. If you want to pretty it up a bit, remove the parts of the servo mounts that now stick up above the servo - loses about 2 grammes in weight too!! ( ;D LOL)

Don't fix your servo with tape, or glue, or anything other than posts properly screwed to the chassis and the servo - it will end in disaster! HTH :)

[Pro_3_racer]

kool

i will have to give it a go and seeing as it looks a quite a good thing i dont mind drilling hole in the mounts lol

Michael