14 replies to this topic

[NDW]

Hey guys,

I've gotten another one of those baggies, filled with beautifully manufactured parts, precisely as how I drew them

On the left, the parts needed to make the 'DTSW version' of my Kimmy chassis. That German ruleset prescribes a maximum width of baseplate, being 70mm. My Kimmy is much wider then that, so I've narrowed the plate and replaced them for carbon 'arms' to skirt the rules a little, as it literally says: 'Nothing heavier then aluminium may be wider then 70mm'. So, with the arms, the chassis stays exactly the same as the original one and the additional weight that is needed, can be placed on top of the carbon arms.



Here's the DTSW chassis put together.



This is the latest trend in the German SLP series, so for a change, I'm copying something..



I'm curious to how it'll go, I'm after better results in the SLP next season!



Next is a funny project. I know of course many slot cars had steering fronts already, but I wanted to design, build and race one of my own and hope it'll perform as good as a normal lay-out would, cause just imagine going sideways... and seeing the fronts wheels steering out?









More to follow soon and check out more at my page:

My Picasa

[GearBear]

Nice job on the steering linkage! Looks really nice.

One of these days I'm going to have to get one of these cars to play with. They are just too nice!

[gascarnut]

Next is a funny project. I know of course many slotcars had steering fronts already, but I wanted to design, build and race one of my own and hope it'll perform as good as a normal lay-out would, cause just imagine going sideways.. and seeing the fronts wheels steering out?

Nice parts, nothing looks as good as nicely machined carbon fiber and aluminum (except maybe for carbon fibre and aluminium).

But (isn't there always a "but"):

The way that the steering geometry is set up, you have what could be called "reverse Ackerman" geometry. The outside wheel is turning through a greater angle than the inside wheel, and it should be the other way round. You need to work out a way to pivot the steering plate on or near the inner of the three mounting holes for the axle block, so that the imaginary line from the steering link attachment point that goes through the pivot point will intersect the centerline of the car at or about the rear axle. The way the plates are right now the intersection of the left and right side lines are way out in front of the car somewhere.

Of course, since the tires are coated and have no grip, the effect on the car is going to be minimal anyway, and my guess is that the slop and play that will be needed to make it all move smoothly will detract from the support the front wheels give to the guide.

But it looks like a fun thing to try, let us know how it works, I would like to be wrong!

[Foamy]

This is correct. Make the tie rod connecting the steering blocks behind the steering blocks. I would guess 3 or 4 mm narrower than the kingpin pivot. Connect the guide to one side steering block, left or right makes no difference. That "should" get rid of the anti-Ackerman.

This is reminding me of my 1/12 R/C scratch building daze days.

[Alchemist]

All I want to say is "awesome", Nick! Keep the pictures coming please!

I always appreciate "engineering exercises"!!

Ernie

[gascarnut]

This is reminding me of my 1/12 R/C scratch building daze days.

Just what I have been thinking as I watch these developments and others!

It's all just half-scale to what we were doing in 1/12 R/C.

The next thing on that pivoting rear section will be three tiny shock/coil units, or a friction damper set-up.

But, please keep going - I LOVE to see the thought processes and the exquisite machining that comes out of them. The parts are just so pretty...

[NDW]

Hey guys,

Thanks for the replies.

First, I know about the Ackermann concept. But, because I simply suck at math when trying to calculate angles and degrees, I thought I'd not make myself any harder then what it already was. In this layout, both front wheels steer under the same angle as the guide does, if we leave out the play in the parts. Simply when I turn the guide any amount in my drawing program, the front wheels both turn the exact same amount, hence the arches at both ends of the steering bar instead of just a hole.

I've added this rubber band, which eliminates all the play in the parts. And indeed as mentioned above, the front wheels are coated and I think that to a certain extent, it doesn't really matter what you do with them.



But don't forget, this one was just for fun, not directly intended to be perfect at the first dip in the water.

I did make sure however that this assembly fits my normal chassis without modifications so the idea is that I can take any of my existing cars, and simply swap the front ends to see how the steering fronts influence the handling.

On the left is the steering fronts assembly, on the right the dismounted normal layout.





And here's the DTSW version of my Kimmy, finished and small improvements will be made after this first sample before it goes into production.



Again here, many of the parts simply fit this chassis, the normal Kimmy, the steering fronts and some even fit a standard SLP2. I like compatibility.

[gascarnut]

Nick,

Thanks for the extra photos - it's always cool to see these developments.

Will you bring this chassis to the PanAm race in Chicago? I would like to see it from close-up.

Thanks!

[Bob Campbell]

The way that the steering gemometry is set up, you have what could be called "reverse Ackerman" geometry. The outside wheel is turning through a greater angle than the inside wheel, and it should be the other way round.

Hey Dennis,

The reverse ackerman might not be a big deal. Most Porsche cars are designed like this. The theory is that with a bigger slip angle due to higher loading of the outside tire there has to be more angle to generate the same turning force as the inside wheel.

Check out "Tune to Win" by Carrol Smith. This book will explain better than I can.

Bob C.

[tonyp]

I love these they are so cool. I should ask Debbie to get me one for Christmas....

[Tex]

Hey, Tony, ask her to get me one too.

[tonyp]

Even if she buys me one you know who is actually paying for it.

[NDW]

Hey guys,

Yes, I'll be bringing as many of my toys as I can carry.

Some to show, some to sell should anyone be interested.



Also this Formula Le Mans car will be looking for a new owner.





I'm curious to see what I'll be racing in Chicago, as I'm so lucky to get cars built for me as I would have absolutely no idea what to do anyway.

[Cheater]

The reverse Ackerman might not be a big deal. Most Porsche cars are designed like this.

My Sunbeam Tiger also has reverse Ackerman steering, due to the fact that the steering rack could only be placed ahead of the front axle centerline when they stuffed the Ford V8 in place of the anemic Sunbeam four cylinder.

Every time it is driven on concrete in a parking garage, one of the tires "screams" at you...

[Springbok Racer]

Nick,

Just two points: the ausFORCE Aston that you are taking to Chicago is not for sale AND you must please put the FLM car (the one that is fore sale) in the box when you send the ausFORCE cars back to their home downunder.

Cheers

Jan