RedBullFiXX

iTrader: (34)

Mini Lipo, as in 1S fits perfect in the 104
And would be an awesome platform for old school Cigar F1 style cars.

jhberger

iTrader: (1)

With a chassis that narrow, you could throw some skinny tires on and have a pretty fair Formula Ford replica. Talk about entry-level racing!

daleburr

My approach to F1 design. It has independent roll and pitch springing and damping.

Weight distribution is optimised for outdoor racing where rear traction out of the corners is vital; I generally run 4 cells in the rear slots which gives me about 62% rear WD. Weight is perfectly balanced left-to-right without any lead or tweak adjustment needed.

I chose a t-bar design as I'm convinced that a link design isn't the right approach for a car with wings mounted on opposite sides of the pivot.

It uses standard F103 wheels and tyres which I thought was important for the scale appearance (plus most tracks ban the use of GT wheels).

The car currently has the lap record at my local circuit, and is getting pretty close to GT10/WGT pace.

akura2

very cool... the Mini Lipo they are talking about on the Exotek site is a 7.4V Mini Lipo (1800mah) so you're getting the smaller size, lighter weight, narrow bodies... but you still retain the high voltage for the speed...

and with silver can or 21.5, an 1800 is all you need for a full race

What turn motor are you running? and how is your weight distribution? How does it handle with rubber tires and which ones are you using?

InZane

iTrader: (2)

Very nice car!

I'd like to hear some more about your theories on T-bar cars vs link cars. To me the motorpod is pivoting around the rear pivot ball of the T-bar very much the same way the pod in link car does - what's the difference as you see it?

The rear looks quite wide - is it 200mm?

daleburr

The difference is that the T-bar acts as a spring in both directions; when you hit a bump, it prevents the chassis grounding, and when the wings press down at high speeds, the T-bar will prevent the pivoting (at least to some extent, dependant upon the downforce and T-bar thickness). I run the thickest t-bar available, and don't use the front grub-screws so it has no effect under roll.

InZane

iTrader: (2)

I'm not saying you are wrong - I'm just curious.

Isn't the center shock&spring pretty much doing the same thing as the T-bar - restricting droop (pivoting down/rear) and preventing grounding?
And isn't no grub screws pretty much the same thing as no side springs?

...edit ...
I noticed your sideshocks have springs - clever! The problem with T-bars are that they change their flex characteristics with age - link cars are more consistent IMHO.
... end edit ...

InspGadgt

That depends on the design of the T-plate and how it is mounted to the pod. The older style T-plate did flex around the rear pivot point so that is true for the most part. But the newer style symmetrical T-plates, when not using the center screw, twist around the arms of the T so the pivot point is further back. When you add in the center screw it will move the flex point more forward.

Sydewynder

When you say newer t-bars are you referring to the f104 but not using the oring pivot? Would this give you a softer side to side roll?

This sounds like the mini z rear ends.

InZane

iTrader: (2)

I'd say that I'm quite familiar with both T-bar and link cars and how they work - I raced my first T-bar car more than 25 years ago .. I think it was a Delta 1:12. I've made a fair deal of A-mains on Swedish national level with AE RC12s, Schumachers and Corallys as well.



My first link car was one of the first to be produced (as far as I know) - the Composite Craft/TRC Lynx II (the 1:12 is a mid 80's T-bar Corally).

This is still one of the best handling cars I've ever run in my career, I won ten straight races with this car in 89 - and it had a rear wing mounted on the motor pod.
I own both a F1-09 (link car) and a F104 (T(H)-bar car) and the F1-09 outperforms my F104 whatever surface.

RC chassis design is one of my greatest interests and I'm always eager to hear other drivers points of view when it comes to setup tips and chassis theories.

I'd like to know a bit more from daleburr about what particular benefits T-bar cars have compared to link cars when it comes to chassis with the wing mounted on the motor pod.

Sydewynder

The way the rear wing is mounted it will always cause chassis "jacking" whether it's pivot (link) or T bar. The only way you can get rid of this is to have a wing mount that's at or in front of the rear axle. For the best use of downforce it should be at the axle axis (not in front) so it pushes down directly on the rear wheels and not compressing the pod/chassis down.

Sydewynder

@daleburr

Is your T bar mounted on 2 pivot balls?

daleburr

Yes the t-bar is off an RC12, so it uses the plastic pivot sockets with metal pivot balls inside. It's the symetrical type so I have the option of removing the centre of the 3 screws at the back, although so far have chosen to leave this in as I think it will be stronger in a crash.

Regarding the jacking and rear wing position, I agree 100%. Since those photos were taken I've fitted a different pod that has allowed me to get the rear wing much closer to the axle. It's still behind it (if I put the wing over the axle its way too high), but is about 20mm further forwards than before. This has made a huge difference to the high-speed grip and stability.

daleburr

If you remove all the droop from the link car then that's certainly true, you will prevent all of the downforce/pivoting effect. And on a smooth indoor track that might work pretty well. But on a bumpy outdoor circuit I normally end up with a few mm of droop, so the shock doesn't limit the pivoting at all.

Comparing the F109 as a link car to the F104 as a t-bar car isn't really fair; the F104 is 20mm narrower, has 10mm narrower tyres and has a very crude t-bar setup, so really the F109 should thrash it. That said, Andy Webb at my local track is actually faster than all the F109s with his F104 (which is very impressive for such a narrow car, I don't know how he manages it!!!).

A fairer comparison is to compare my t-bar car to the F109, since both are 200mm and use the same tyres. Unfortunately I don't have an F109, so no fair comparison has yet been done. I'm about half a lap quicker than the closest F109 is the only comparison I can give.

I have been considering designing a link-car for next year, as NiMhs are getting harder to find, so maybe then I'll have a fair comparison! If I do decide to do this, I'll still try to find some way of limiting the jacking, such as a shock absorber that provides 2-way springing.

I'm still a newbie to pan cars really; most of my experience is with TCs and real F1s, and I'm loving the freedom you have with the design of these cars, and with how fun (and difficult) they are to drive

Sydewynder

Is the initial roll of the T bar loose on the pivotballs then it twists? If so, how does the car handle with just the side springs' resistance then with the T bar forces added?