ouch... at least its minor damage. How that happend to the shaft iscrazy!!!

overdriven, could you please explain a little furthur about the belt driven touring cars and how their performance differs to shaft vehicles

As the shaft spins it creates force(centrifugal?) to one side of the vehicle and it slides. Atleast that's what I read on drift forums.

I got this fixed up this morning and am pleased to see that there was no major damage. When it happened I was expecting to see broken bulkheads, etc. But just arms and driveshafts. I recently put 4mm screws through the chassis into the bulkheads - I think this made a difference (the 3mm screws I had there had bent slightly from a relatively minor impact previously). With a wreck with something this heavy at high speeds, something has to give. So I'll stick with plastic arms and let them be my weak point - they're cheap and I already have a bunch of extras (no Al arms for me!).

To my understanding it's not centrifugal force that causes shaft driven cars to drift or wander. It has more to do with the torque being transmited through the shafts under acceleration and how it acts on the chassis. The effect is more gyroscopic than anything.

Either way, it's created by the motor trying to accelerate the car through the drivetrain. If you've ever powered up an electric motor while not attached to anything and watched the whole thing spin around, that's kind of what's happening here. Now picture that force in a typical shaft vehicle and you can see that force wants to push the vehicle to the side.

During acceleration, a powerful motor may already have the tires on the edge of traction. This makes it easier for this gyroscopic effect to Break traction and push the car to the side. Touring cars have a relatively small tire contact patch for their size and weight. They are also sensitive as far as handling goes, so brushless motors almost forced these cars to belt drive. Brian's creation weighs alot but is just so powerful and on grass so he's seeing the effect also. I've seen it on my 1520 powered erevo on 6s as well.

I'm not sure if belt drive creates any gyroscopic effect of it's own. But the layout of the motor shaft and pulley shafts means any forces would be directed to the front or rear not to the sides.

I read the entire thr3ead and didn't find the answer.

Hey brian015- you are running 23mm hexes in a 24mm hex wheel. Did you do anything about the size difference or are you just letting her buck? I want to run those wheels/tires on my LST. Thanks! -Harold

Yes - 23mm hexes in 24mm wheel hex.

Don't make me admit what I'm doing! :cry:

I'm using a very high-tech solution called folded over aluminum foil wrapped around the hexes to fill up the space. It's worked fine. When it has fallen out, they run without a problem, too - I didn't see any damage to the wheel hexes. If I get around to buying some aluminum tape, I'll use that and it will probably stay in better.

-brian

How is the custom front shaft holding up Brian015

No problems whatsoever - I'm very pleased so far. So I haven't needed any of the green loctite yet. :smile:

-brian

.5mm slop on each side really shouldn't be a problem with such a large hex.:yes: I'm just glad to hear someone else is doing it before I take the plunge!

Here's some aluminum tape if you can't find any anywhere else: http://www.davesmotors.com/s.nl?c=88...0mm%20x%202.5M

My suggestion for the tape would be to drive through a new residential construction area and ask any HVAC (heating ventilation air conditioning) guy for a little, they'll probably give you a roll! (that's how I put racing stripes on my '84 crx- uber cool!)

Thanks for the info Harold.

I got tired of cleaning out all the dry grass that was accumulating inside my truck - around and under the center driveshafts, with so much piled up in front of the rear shock tower, it looked like I had a bird's nest in there after every run. So I made some simple side body panels from .03" lexan:

http://i779.photobucket.com/albums/y..._4513Small.jpg


It also serves as protection for my components. I didn't realize it until I painted these yesterday, but I had the black parts on the truck unpainted when i had my accident the other day - and you can see the dent a couple inches behind the front body clip, a dent which otherwise would have been in one of my batteries!

I'm only putting these on the sides, so I'll still have good airflow down the center of the chassis and air cooling should still be good. When I tested these out briefly last night they worked great - no junk inside!

I finally got a chance to get a video of this on 8s. Here it is:

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/YJr4-wKNuhs&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/YJr4-wKNuhs&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

Looks like it floated over that jump. Nice car!

Thanks - I've been jumping this some more and really like how it handles. The one breakage I had came after I cartwheeled after a jump - the large inner bearing on one of the axles blew apart.

I know I'm stressing the axle bearings with the wheel extensions and heavier 5b wheels/tires (and heavier truck when it cartwheels). So I'm waiting on a part but I'm planning to add a bearing to each axle inside the carrier to bear some of the stress. I'll post pics when I get it done.

The other potential weak spot that I want to try to reinforce is where the bulkheads connect to the chassis. I bent 3mm screws there so now have 4mm screws. But with them going into plastic I just think it's a matter of time before they fail too with the added weight of this truck. So I bought some 70mm m4 bolts that I'll put through the bottom of the chassis, up through the bulkheads and bolt them to an aluminum top plate that I'll make. This will eliminate the weak spot of the screws into the plastic bulkheads and should be much stronger.

I have no desire to put $ into aluminum bulkheads, so this is my alternate fix.

Edit... I thought i had commented on your vid already... Your extended truck is jumping very nicely... Horrible when the tumble though isnt it... :) Are you going to be investing in the new castle ESC when its comes available???


i know what you mean about destroying bearings in the axles... One of mine fell apart the other day and i couldnt get the outer rim of the bearing out of the carrier! Was so annoying... how would you add another bearing without shortening the drive shaft and extending the axle? Really interested if you can come up with a fix... I was going to do a big boca bearing upgrade, but considering the stress put on the axles i would prefer to change the axle/hub bearings with cheap ones as they wont last long....

You bulkhead issue, i have realised due to the extra length of the chassis, a lot more stress is put on bearings, and more movement is found in the bulk heads. I have carried out you idea but it only last so long. Some GH Bulks are my next upgrade. Expensive, yes... keep my diffs protected and bearings free from stress, yes... I think its a necessary upgrade now... smething i have been trying to avoid in adding weight and cost.

I'm happy with the mechanical brakes on this, so I don't think I'll need the HV truck esc.

I'm planning on putting an extra bearing inside each LST2 carrier where there is now empty space - in between the two current bearings. For the front spindles it looks like only very minor shimming to get a snug fit. For the rear carriers I'm waiting on some thin-walled aluminum tubing to use between the bearing and carrier for a solid fit.