Schumacher to Re Release the Cat XL!

[oldenoughtoknowbetter]

Originally Posted by isobarik

LOTs of parts in the front end so is a bit fiddly.

All of the holes line up etc but when one side is on the plastic side parts arent even vertical and throws the front casing out then the other side is about 4mm out. when looking at it front on the plastic side parts are at a really strange angle. Jesus. Ive built dozens and dozens of cars over the years but im done with this one!!

[oldenoughtoknowbetter]

Im done with it. first person to make a decent offer gets it. Im sticking to predators!!!!

[tahustvedt]

I ordered one now. Can't wait to struggle with step 19.

[oldenoughtoknowbetter]

probably just how i tried to build it. decided sell it now though lol

[bluewormx]

Never give up! you just spent 4 hours. Leave it a few days, and try again. You will get it once you are rested and relaxed.

Bare in mind th actual clamping is done by the top plate and the chassis. The transmission needs to be able to sit in the cutouts on top and bottom.

Any imperfection in the tranny case or the chassis plates will not allow this. Try bolting it up without the 4 guides to make sure it sits in the correct place, and to better help you understand where everything goes.

Then try one side. Remove the two right hand bolts.

place the lower guide first and insert the rearmost bolt half way in, then insert the top guide, it will be a tight fit perhaps loosening the other two bolts half a tuen will give you enough wiggle room.
Once you have inserted the top guide push the rest of the bolt in and put the washer and nut on, snug down and put in the forward most bolt.

Tighten both down and loosen of half a turn.

Now do the same with the left had side.

It may seem hard but take comfort in that the original car had 8 screws plus thick washers under the bumper wich made it way fiddlier

[isobarik]

Originally Posted by bluewormx

Never give up! you just spent 4 hours. Leave it a few days, and try again. You will get it once you are rested and relaxed.

Bare in mind th actual clamping is done by the top plate and the chassis. The transmission needs to be able to sit in the cutouts on top and bottom.

Any imperfection in the tranny case or the chassis plates will not allow this. Try bolting it up without the 4 guides to make sure it sits in the correct place, and to better help you understand where everything goes.

Then try one side. Remove the two right hand bolts.

place the lower guide first and insert the rearmost bolt half way in, then insert the top guide, it will be a tight fit perhaps loosening the other two bolts half a tuen will give you enough wiggle room.
Once you have inserted the top guide push the rest of the bolt in and put the washer and nut on, snug down and put in the forward most bolt.

Tighten both down and loosen of half a turn.

Now do the same with the left had side.

It may seem hard but take comfort in that the original car had 8 screws plus thick washers under the bumper wich made it way fiddlier

i bought an cheap of an auction site in sweden i drilled it out and took four bolts in stead down side is it looks so nice when you have flush screws on top and not an nut.

mvh isobarik

[THancock]

I'm doing something wrong...

I'm running the car with a 19x1 brushed motor (Atlas) on grass with the original tyres, yet I am suffering with two persistent problems:

1. The front belt slips (load clicking noise) unless I am very gentle with the application of throttle. I cannot move the front gearbox any further forward physically (and the belt has little slack), nor tension the rear belts any more without binding the transmission.

2. The spur gear diff melts around the balls.

I've built tons of ball diffs in the past and used the same run in procedure with the Cat. The diff action was lovely and smooth and there was no slip (rotating by hand). But as soon as it is under load from the motor, after a couple of minutes, I can feel the slip in the transmission and sure enough, the spur diff is hot as hell and if I'm too late in stopping, a sticky plastic mess.

Any advice on what others are doing would be appreciated.

- Tim.

[Peakey]

Originally Posted by THancock

I'm doing something wrong...

I'm running the car with a 19x1 brushed motor (Atlas) on grass with the original tyres, yet I am suffering with two persistent problems:

1. The front belt slips (load clicking noise) unless I am very gentle with the application of throttle. I cannot move the front gearbox any further forward physically (and the belt has little slack), nor tension the rear belts any more without binding the transmission.

2. The spur gear diff melts around the balls.

I've built tons of ball diffs in the past and used the same run in procedure with the Cat. The diff action was lovely and smooth and there was no slip (rotating by hand). But as soon as it is under load from the motor, after a couple of minutes, I can feel the slip in the transmission and sure enough, the spur diff is hot as hell and if I'm too late in stopping, a sticky plastic mess.

Any advice on what others are doing would be appreciated.

- Tim.

The thing with the cat is the diff is in the layshaft not the rear drum like your use to. If you hold the spur gear and the rear wheel the same side then turn the opposite wheel you'll thigten the diff as it sounds like it's running a little loose.

[THancock]

Thanks Peakey. I'm still a little confused, sorry

I understand the integrator part and that bit appears to be okay, but with regards to the layshaft diff, which bit is acting as the diff? The inner layshaft balls and rings or the spur gear balls and rings or both?

I was using the nut on the layshaft by the spur to tighten the diff action - is that wrong and I should just use the approach you described?

[tahustvedt]

Very odd to have the diff in the layshaft. The torque there is lower than at the rear axle, but the radius is equally smaller, with fewer balls to absorb the torque. I look forward to building it though. I have a 13,5T brushless that I want to use, but maybe I'll steal the 17,5T from my Ultima Pro instead. I think the recommendation of no hotter than 17,5T seems a bit conservative. My Procat has a 13,5T motor which it handles without slipping.

EDIT:
Actually, studying the build manual, the rear diff load seems to be shared by the rear axle, the spur gear AND the layshaft. There are ball bearing diffs all over the place.

[daz75]

Sounds like a degree in car building is needed for this that's me out

[isobarik]

Front diff
Rear diff / integrator
Layshaft diff

Tightening the rear diff makes IT drive the front
More atleast so you have 50/50 drive

Med vänlig hälsning, isobarik

[tahustvedt]

Originally Posted by daz75

Sounds like a degree in car building is needed for this that's me out

It's a lot simpler with the upgraded drive train kit. Download and read the manual for more info: http://www.racing-cars.com/pp/Car_Sh...LS_Masami.html

[tahustvedt]

This 1989 video is a treat for us CAT fans. Schumacher's set up tips for the Cat XLS.

https://youtu.be/qz_3mnRPF24

[Danf1275]

Originally Posted by isobarik

Tightening the rear diff makes IT drive the front
More atleast so you have 50/50 drive

Integrator tension controls front drive - rear diff only controls back axle. Not hugely experienced with original drivetrains, but I try to run integrator on my originals as loose as possible, without excess slip, to reduce drag on rear diff action.

[tahustvedt]

I can imagine the rear axle diff feel is tighter with a layshaft diff than with a normal rear ball diff, because of the gear ratio between the rear axles and the layshaft.

[tahustvedt]

Mine arrived today. Took 5,5 hours to build it. There were two issues. One was that the bag for step 16 included a wheel hub instead of the diff hub. The wheel hub is longer. One picture shows the longer one next to a normal diff hub. Luckily I had a spare one from the old days. Anyone else encounter this? Also, the front diff bolt was shattered in the end. I wonder what happened there. Probably hardened while rolling the threads. I contacted Schumacher about these things in case it's not an isolated incidence.

I did not install the rear gearbox housing early on as the instructions call for. The shorty battery mounts interfer with some screws on the gearbox housing, so I left it hanging loose until the front side plate scrws were in place.

Step 19 was not a problem. I just inserted one screw at a time, fitting it through the parts.

Step 22 is installing the rear A-arm pivot blocks. The instructions say you should insert screws into holes that are already occupied by shorter screws. This can be confusing to builders who aren't sure how it's supposed to go together. The shorter screws have to be removed first if they were installed according to the instructions.

Will probably paint it tonight or tomorrow. I'm not sure if I should go for box art or a flaming variation of it.

[tahustvedt]

I didn't have any red paint, so I made a fiery inferno look with some black, orange and yellow. I wish they included the same decals that the original had, but I guess HPI must have objected. Maybe we should bug HPI into reproducing the Blue label motor... with decals.

Now comes the most difficult part of any build; having the patience to leave the freshly painted body alone to dry so that the soft paint doesn't scrape off when trying to put it on the chassis.

[tahustvedt]

I'm happy with how it turned out. Now I just need to wait for the motor and ESC.

[tahustvedt]

17.5T SKYRC Cheetah sensored motor and ESC with 26T pinion
2S 4200 mAh Gen ACE shorty lipo

The ESC barely fit between the steering servo and the battery post. I think they should have moved the battery posts backwards about 2 mm. I have a smaller ESC on order. This is just temporary. I cannibalized the ESC from my BSR BZ-222.

The car handles this kind of track surface superbly, which is no surprise as it's close to how many tracks were in the 80's. The tires are perfect for grass, moss and exposed soil.

Something was chirping. Probably the rear diff (layshaft) so I took it easy on the launch. The rear diff is very stiff due to being situated in the layshaft, but still chirps, unless it's the front diff that chirps. Will find out soon.