As a side note, ifmar rules for electric buggy world championships put fwd cars in the same class with 4wds, not 2wds. Even though fwds are 2wd...

I know :( They should change that though, it's an old and outdated rule (not just from the IFMAR) and was put into life to make sure drivers didn't buy a RWD and built a FWD and use one that best suited the track. They however could easily have solved this by stating people should choose their chassis for a whole season, or in case of the FWDs before the track was anounced.

Is that different from being able to choose if your rwd car is mid or rear motored depending on the track?

Recently there have been released some chassis' that allow mid motor and rear motor options on the same car, and I think in the long haul, more brands may follow (despite what I'm stating below).

Plus, I read here on oOple (first page of this topic) that the IFMAR only runs on 'natural' surfaces - so I guess mid motor cars are not a popular choice for IFMAR races anyway - no astroturf, no carpet and no other high grip surfaces a mid motor chassis has the edge over a rear motor chassis.

Time for another update :)

http://i65.photobucket.com/albums/h2...creenshot8.jpg
http://i65.photobucket.com/albums/h2...creenshot9.jpg
http://i65.photobucket.com/albums/h2...reenshot10.jpg

First off, the body choice:
DEX410 body and Bugle 410 undertray, but hopefully in the long term a custom (extra) front cab body based off the chassis dimensions/curvature of the DEX410.

The second thing, the steering:
The TLR22 steering has arrived, I really like how simple and beefy it is. I measured it and though I can't make the front assembly as compact as I hoped, it does seem to get me the right geometry.

And some progress on the chassis plates:
I made a start on the design of the chassis plates. There is an upper chassis plate, to which two braces mount that reinforce the shock tower. The steering also mounts to this chassis plate. Then lastly, at the rear ends of this upper chassis plate, there will be two posts. These two posts are to reinforce the structure and the battery plate will also mount to these points. The battery plate will run over the battery to a rear upper plate. By changing the battery plate's amount of material or the material itself I can hopefully adjust flex in the chassis if needed.

As I think it's necessary to have an adjustable wheelbase on this car, I am considering to split the lower chassis plate in two pieces as well. Either that, or I need to make many mounting holes at the back for the bulkhead.

And last but not least, a bit of re-designing:
The feature is not yet visible on the pictures, but I've added it to a newer version: The rear suspension blocks of the front end will not be mounted straight to the lower suspension plate to prevent potential damage to some expensive custom parts (front suspension arms, lower chassis plate). The two blocks will be mounted to a small plate, which is then mounted to the lower chassis plate. By deliberately making it the weakest link in the construction I can prevent the expensive parts from breaking (as 'regularly' as they usually would).

I'm currently working on the rear suspension and I got a question to ask you guys.

For the rear I'm using the front suspension arms and, hubs and uprights of the TRF201. I'll use the turnbuckles that normally are for the steering to set up the rear toe angle.

I could use the front suspension as intended, but it puts the turnbuckles of the steering exposed to impacts on the rear of the car. I'd like to turn the uprights around to get the turnbuckles in front of the axles. However, this also puts the rear axle in front of it's steering/pivoting point.

Normally this would cause bad handling, but I was wondering if this also applies when the rear wheels don't steer (apart from perhaps a tiny bit of bump steer)? :confused:

http://i65.photobucket.com/albums/h2...reenshot11.jpg
Here's a picture of what I mean...

Any slop in the ball joints and that will cause some bad rear end wobbling and it's pretty much impossible to eliminate all slop. Much better to have the axles trailing.
Could grab a sheet of Kydex and make a decent rear bumper?

Thanks for the advice :) It's a pity I can't make it like I had it in mind then: I was hoping I could put the shock tower in front of the shocks, so the plate would be just in front of the rear suspension arms. (a lot like the RB5's front end, but then on the rear of my car). You'd end up with the weight slightly less to the back, and a very low construction between the suspension arms itself (and to be honest, I'd do that just to make it look cool :lol: ). I can still do this, but I need to make a second, smaller plate for the toe turnbuckles if I do that.

A bumper may indeed be a good idea. I can also go for the option of constructing the rear end in a way that the shock tower will absorb most of the forces when it's hit on the rear end: A bit like the front end of the B44 and the Yokomo YZ-10 (which by the way looks very good as well imo)...

I don't know if it is available for the 201, but AE sells inline steering hubs that you could use to get the toe-in turnbuckles inboard.

Really cool project BTW, makes me want to build one :thumbsup::drool:

Thanks for the compliments and info :) There's no such part for the TRF201, but it does inspire me to make it myself :lol:

Awesome looking project so far! I'm really interested to see how it turns out.

Will you be running this on astro or dirt?

I've found that on dirt wheelspin / forward traction is the main challenge to overcome. I can't wait to see how your design runs - we certainly could use more FF buggies running to test and refine designs.

I modded a FF-03 into a buggy and it had a battery layout similar to yours but on the dirt where I run the car really struggled for forward traction.

I just haven't gotten round to it but I've gotten all the parts needed to install a gear diff in my original FF (dubbed YKP locally)... plan is to put really hard oil in there to reduce the loss of any power especially on rutted areas of a dirt track.

Good luck, I'll be following this thread with interest!

Nice to get some info on the FF03 Buggy you made! I saw it on your Blogspot - and I also saw your RB5 (gearbox) based FF buggy which looks absolutely awesome :) Did you manage to keep the last one under 250mm wide at the front? I couldn't find a way to do that with the DB-01 arms, hence I chose for the custom front arms.

As for the terrain and weight distribution... I don't have a track that I usually go to (yet), though my preference goes to a natural surface (dirt, clay). Like I mentioned before, I want a narrow chassis and unfortunately I don't have saddle packs, so I'll need to play with under servo etc. weights if the the front traction is bad. It's good to know about it though, perhaps I can design the car to accept shorty LiPos and/or saddle packs as well in the future without the need for new parts :)

Your going to need more work at the front or rear of original, no kick up no caster and toe out on arms

Could I ask you what you exactly mean? :confused: Do you mean there is no kick up and it needs some, that it has toe-out and must be removed or needs it and doesn't have it yet, etc? :)

Edit 30-12-2011:

http://i65.photobucket.com/albums/h2...reenshot12.jpg

This is a new plan for the chassis layout. That, or with the servo next to the battery. The plan is to build a (partially) custom steering set which allows me to run the steering rack over the battery. Reason for this is the advice I got several times to put the weight further forward, and the TLR22 steering rack may not give me the desired steering geometry (so I need a different system anyway).

The chassis plate as you may noticed is also split between a main plate and rear plate. I want to make the wheelbase adjustable, and with the system I can hopefully also adjust the chassis flex (by using further forward or rearward mounting points between the two plates, or using a diff/slipper spring in the mounting points of the rear plates).

unless your redoing the arm mounts the kick up inboard toe in will now be toe out, your also going to need to run the motor in reverse, not the best way to get good performance from a sensored system.

Thanks for the advice :) I already had the 'toe-out' effect neutralized by using the small DB01 front suspension blocks, which can be mounted any given length apart. I thought it would be good to make the suspension shafts parallel to each other.

As for the motor, I was completely unaware that sensored systems have different performance in the opposite direction! I guess I should take a sensorless system then, it also saves some money that I can put to good use on the chassis!

Mark, what do you mean by 'master'? I'm not familiar with that concept and curious.

o.r.b., maybe you can copy the design of many 4WD's: battery on one side and the electronics on the other. Just keep the battery a little closer to the centerline since you don't have the moter on the electronics side to help balancing the weight.

With steering at the front end the toe in is set at the steering block, nothing to do with the inboard setting. Caster is also set at the outer end.

As for the inboard toe out, from earlier in the thread:
Just because rwd buggies have a lot of front wishbone kick up doesn't mean a fwd buggy should have any, in fact it's probably a good thing to have some pro-squat by having the front wishbones leaning forwards to try and prevent the front end lifting under power.

Update on the steering:

http://i65.photobucket.com/albums/h2...reenshot13.jpg

http://i65.photobucket.com/albums/h2...reenshot14.jpg

http://i65.photobucket.com/albums/h2...reenshot15.jpg

I have replicated the TRF201 steering arms and tried to come up with a compact steering system at the front. I'm still not sure whether it will be the servo or the battery to be fitted between the steering arms, but either way the idea should work well. I hope the maximum deflection/steering lock of the DB01 uprights is enough for a tight cornering car.

The geometry is ok in terms of the Ackermann angle: At the steering lock the angle is slightly bigger than needed for the 'ideal' angle of Mr.Ackermann's theory (in which the two lines coming from the front axles cross at the axis resembling the rear wheels). I read a bigger Ackermann angle would lead to predictable, unagressive steering behaviour: Something that should suit the consistency and smooth driving style needed for driving an FF quickly. However, I also need to keep in mind that a bigger Ackermann angle may reduce the amount of steering I have.

There's a couple of issues I still need to solve:

1. Decrease the massive amount of bump steer when the outside of the suspension arm pivots below the horizontal point. (Above that point the bump steer is minimal)
2. How to build the front end around the steering geometry I developed :lol:

interesting project but.. I'm not sure about traction on slippery surface... imho FWD is good for low-power motors (as in video you've posted, 1/10th buggy with 400-size silver can).. But with stronger motor it will have lot of wheel spin and no acceleration because of weight transfer towards to rear-end of car.. That's why I'm trying opposite project in RC rallying (there're lot of FWDs - based on Tamiyas FF-s or M-s - and no RWDs because there is no base onroad RWD with IRS), because FWDs has poor acceleration and have problems with jumps and hill climbing.. but RWD handling is much better, closer to 4WDs.. I think that buggy wil be very similar = good for high traction - low power, but not for low traction or high power conditions.