Back in Time - XLS For Vintage Racing

[DerbyDan]

This is great... watching everyone's builds ready for the revival meeting... can't wait to see them in action

Seems everyone is going to be running something of unknown quantity.... I managed to hook the electrics up in my two Losis - the XX is running my old LRP ESC that I ran in my original XX along with an old brushed mod motor, neither of which haven't been used for many years

[Groomi]

Time is running out and progress has been slow, although the car is practically complete (albeit a more basic spec than originally intended). I haven't had chance to take many photos recently, however here is an interesting one for you:


I mentioned previously that I wasn't confident about the grub screw fixing for the Wasp slipper, much preferring the pin arrangement used for the standard MMS layshaft adapter (Left), so I bought some 20mm M3 stainless steel grubscrews (Middle) and my mates Dad turned them down to form a grubscrew which also acts as a pin through the layshaft (Right). It fits perfectly and is a weight off my mind.

[Peakey]

How did you get on with the roll bars as I'm after a couple of pairs if you fancy knocking up some

[Groomi]

How did you get on with the roll bars as I'm after a couple of pairs if you fancy knocking up some

Would love to, but time is something I don't have at the moment.

The front one worked perfectly, although was a bit tricky to make the tight bends and keep equal lengths both sides. I used Loctite 640 to fix the balls to wire rather than solder - worked perfectly and saved getting the soldering iron out.

I didn't use a rear roll bar in the end. The Procat one doesn't fit because the rear suspension is different and the SWB and XL one doesn't fit because the top suspension mounts are lower than the top of the transmission casing. I did make one up which mounted on the lower GRP brace, but didn't try it in the end. Must do that sometime.

PS: While we're rekindling this thread, what do you guys do to stop the front suspension arms just popping off the balls? I had a torrid time with this issue.

[Peakey]

There's a small screw that should lock it I'm to the ball

[Peakey]

Just found this looking for something else might help abit

http://www.retromodelisme.com/scan_pages/229/cat-schumacher-page-5.html

[isobarik]

Rear transmission assembled with high torque short belts and an unused Bando long belt and mounted to chassis.

where did you get those rearbelts from ???

mvh isobarik

[Groomi]

They were on the car when I bought it in the early 90s. Still have plenty of life in them and coped easily with a 14quad motor.

[Peakey]

Rear transmission assembled with high torque short belts and an unused Bando long belt and mounted to chassis.

where did you get those rearbelts from ???

mvh isobarik

I've just got some from Nigel (npdp72) on oople he also sells them on eBay there not orange but are the newest equivalent to the standard Schumacher belts.

[isobarik]

Rear transmission assembled with high torque short belts and an unused Bando long belt and mounted to chassis.

where did you get those rearbelts from ???

mvh isobarik

I've just got some from Nigel (npdp72) on oople he also sells them on eBay there not orange but are the newest equivalent to the standard Schumacher belts.

thanks but i was looking for some orange rear belts....

mvh isobarik

[isobarik]

They were on the car when I bought it in the early 90s. Still have plenty of life in them and coped easily with a 14quad motor.

are there any markings on them ??? number or ???

mvh isobarik

[Groomi]

Hello All, I can't believe I haven't updated this thread for so long!

OK, well I've been back through and fixed all the picture links so it's easier to refresh your memories of where I'd got to - which was ofcourse, having got the car into some kind of state of completion just prior to the 2014 IconicRC Revival. Well, to be honest the car was a disaster:

The first two heats were wasted as the car cut-out due to high temperatures, this was eventually traced to the 11 triple motor not working properly. I replaced with the Top Missile 14quad motor I used to race BITD and that side of things ran faultlessly...

Well, I started heat three late due to having connected the motor the wrong way around! The car was actually quite quick although the suspension was waaaay too soft and too much droop. The race was cut short however when I clipped the track barrier and ripped the ball joints off on the front end (marshalls had already put them back on a few times), and it pulled the driveshaft out.

Having fixed it all for heat 4 I was going really well despite having realised I'd forgotten to fix the handout transponder to the wing so it wouldn't count anyway, then I did the same thing with the ball joints again.

IIRC the final was much the same story.

I was not alone in finding the old CAT ball joints not up to the job, several others suffered similar fates. But alas, when I got home the XLS was put on a shelf in my office and I tried to forget about it...

[Groomi]

So that brings us up to late July 2015 with the 2015 IconicRC Revival just days away. I'd been rushing to get a Bosscat Works built and was almost finished, so needed to turn my attention to reviving the XLS. Despite having no time available, I was determined to solve the ball joint problems and put in a better showing this year.

To recap, the ethos of my XLS is that it is packed full of period mods. I don't want to resort to modern technology to make it faster, I just want to see what a fully hopped up XLS goes like.

In the absence of any original NIP ball studs, ball cups and wishbones being available on Ebay, I decided on one concession to the ethos, which is to have modern ball joints. I feel that this probably doesn't give much of a performance advantage over the originals when they were new, but will enable me to actually race the thing properly. An uncomfortably compromise, but unfortunately necessary. So with that decision made, I set about finishing the modified front end which I didn't run last year.

First up is the double uprights. Plenty of people have done this before so it's nothing new, but I didn't cut down the outer upright. The advantage of this mod is ofcourse giving an alternative shock mount position which helps to stiffen the front suspension:


Then I set about the troublesome upper wishbones with the integrated ball cup. I had found in a box of bits a pair of modified upper wishbones which had been cut short, drilled and a shock tower mount screwed to each of them, then a short threaded rod inserted in the end an a ball cup onto that. Essentially a cut-and-shut copy of the Wasp upper wishbones. Now the Wasp items didn't come out until the Procat, but there is no reason that someone couldn't have done this mod back in 1987 - infact, if I was the age I am now, but way back then, it's precisely the sort of thing I'd do. So here it is:

[Groomi]

So heading into the 2015 Revival meeting, this was the full spec rundown:

01) Original stick pack XLS chassis.
02) Original XLS bodyset (I got as far as painting the FatCat, but had no time left to fit it).
03) Polished transmission side plates, MMS heat sink, alloy eccentrics and layshaft holders.
04) MMS layshaft and front diff with nylon hex outdrives. Trinity rear diff with alloy outdrives.
05) Wasp orange hi torque rear drivebelts.
06) Wasp slipper with 68dp tufnol spur for authentic whine.
07) Front driveshafts mounted with the outer sleeve on the wheel end, so they can easily be swapped between normal or one-ways.
08) Ball joint and turnbuckle brace fitted between rear of front shock towers, allowing crashback but reducing bending during shock operation.
09) Double uprights to provide additional shock positions.
10) Modified upper front wishbones to provide camber adjustment.
11) Modern ball joints used where possible for reliability.
12) Long screws all the way through the front transmission housing, bolted on top.
13) Front ARB made from piano wire - narrower guage than kit to soften the front end a little.
14) PPB alloy rear shock tower with wire wing mount.
15) New stainless steel 'slothead' screws and nylocs throughout.
16) Kyosho gold shocks, stripped of remnants of annodising and lightly polished.
17) Original chrome 2.1inch wheels with Schumacher full spike tyres in yellow compound.
18) Period 14quad brushed motor.
19) Period HiTec ESC complete with 30amp car fuse.
20) Modern 2.4gh radio gear for reliability.
21) Nimh stick pack.

[Groomi]

So, how did I get on this year?

On track for the practice heat and the car felt pretty good but had way too much steering. So I swapped the front tyres to a pair of 20 odd year old NIP orange compound Schumacher two row studs.


Heat 1: Steering now much, much better which had the bonus of settling down the rear. Reasonable performance but very slow down the straight - infact still accelerating at the end of it, so the gearing was obviously wrong. After the race I changed the pinon from a 28 to a 24 (The spur is 122). Near the end of the race I clipper a barrier and pulled a driveshaft out, but managed to limp to the finish.

Heat 2: The car didn't seem any quicker on the straight, but was much better on acceleration out of the corners, so overall quicker. I found I could drive smoothly and quickly without making many mistakes. I decided that the rear was still a bit too bouncy, so after the race put some 250w oil in the rear shocks (was 200w) which made a slight difference.

Heat 3: Car felt sublime and I drove a perfectly clean race to win easily. Very surprised to find I'd recorded an identical time to heat 2. Sitting in P5 overall, so fairly sure of an A-final start, I decided to take a gamble to try to find a bit of extra pace so after the race I fitted 20 odd year old NIP yellow compound Schumacher stubby spikes to the rear.


Heat 4: I was driving every lap flat out and leading by a country mile. The car felt great, the new tyres were perhaps a touch better than the full spikes and I was driving cleanly and even clearing the table top every lap. The I ran wide on one corner, brushed the barrier and pulled a driveshaft out. Knowing I couldn't improve on my previous times I pulled out. After the race I replaced the ordinary rubber band on the crashback mechanism for a stiffer black rubber belt I had and a shorter backup one for good measure. This stiffened up the crashback mechanism so I hopefully wouldn't have the driveshaft problem again.

So, I lined up 6th on the grid for the A-Final, just behind Dan Ferguson with his XL which had been running great all day.

With an uphill start and most of the other cars running brushless systems, I knew I'd struggle at the start, so I planned to go stay wide and out of the way on turn 1 and then cut in tight to the hairpin at turn 2, knowing that the XLS steering could take me right around the inside. I executed this perfectly and entered the next straight in 4th place. At this point I just didn't have the power to get even a couple of cars length ahead of the cars behind, so as soon as I lifted for the next corner they all piled into the back of me. Dead last I set about trying to catch up only to roll on the next corner. I caught up again and started to pass cars quite easily but then got pushed out again on the same straight and this time waited an age to be marshalled. Dead last again I had to fight to catch up and pass others, eventually finishing 7th and first CAT home.

Looking at my times I did consistent 33sec laps all the way through apart from a 49sec lap when I had the second crash. Gutted about the result, but absolutely in love with my XLS again which proved not only to be a pleasure to drive, but consistent and strong too.