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Peter Brock Volvo 850 and PCB Chassis

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wixwacing
Marshal!!!
Posts: 1871
Joined: Thu Jul 10, 2008 9:22 am

Peter Brock Volvo 850 and PCB Chassis

Post by wixwacing »

Simple PCB chassis for the SCX 850 Volvo

Having been brought up on a diet of four cylinder cars in motor sport it is no surprise that I still retain an amount of affection for those heroes who propel themselves around tortuous circuits at breakneck speed, tachos maxing out and three abreast into the corners in 4 cylinder cars producing way more power than their makers ever expected, all in the interest of motor sport.

One of the most famous series has been the BTCC or TOCA touring cars. Anyone who has played the Codemasters V8 Supercars will see a plethora of cars and circuits that have been entertaining the TV watching motor sport public.

In TOCA there are legends that have been created, French ace Alan Menu in the uncatchable Renault Laguna, Frank Beila in the once banned Audi A4 and Scandinavian maestro Rickard Rydell in the Flying Volvo. Several other teams Like Ford, Nissan, Peugeot, Vauxhall and Honda also contested the series with lesser success. Some drivers have gone on to greater things and others have returned home with lesser achievements.

In the absence of a concerted effort in the ‘90’s to get a coherent touring car class running here, the Australian legacy was the importation of the previous seasons cars from Europe. Although still entertaining, but with only half a field, they lacked the spark of their previous incarnation. Some famous names took up the challenge but the writing was already on the wall. With the likes of Dick Johnson in the Mondeo and Peter Brock in the Volvo, the series limped on until V8’s came of age and Avesco eventually stole the show.

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I still have my little pieces of Euro Tourers at home but although most of them are not very competitive the odd one shines out. The Ninco Audi A4 is one, The Ninco Alfa 155 is another and my comp car was a much coddled Ninco Opel Calibra. Most of the Scalex and SCX offerings aren’t in the same paddock when it comes to those!

While being in between projects an SCX Rydell Volvo on the shelf caught my eye. The car was ly the red Peter Brock version but a chance purchase of a Rydell body on ebay allowed me to add to my TOCA stable. The 05 body lay languishing for several months until this moment when I was determined to restore it to better than its former glory. I had by now built quite a few PCB chassis and was ready to give this a go.

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The PCB was measured and cut to fit the entire underside of the Volvo, the wheel spacing was transferred from the body and cut out, then the position of the drive train and axles were marked on the copper top side. Axles were mounted into vertical tubes which were cross bored and fitted with 3/32 id brass axle tubes. These weren’t fixed yet. The guide position was marked and a short brass tube was mounted vertically to hold it. The motor position was marked and cut. Finally the chassis was fitted flush to the bottom of the body.

The chassis was mounted on two single mounts. These are PCB mounting posts from Dick Smith. They come with brass screws and threads each end and being made of Bakelite cut easily with the Dremel. I decided to mount one front and back for a reason. These were epoxied in place after I loosely fitted wheels and tyres to help with positioning.

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The Axles are cut from 3/32 music (piano) wire from the local radio control shop. I use this exclusively now as it is only a couple of dollars for a metre length. Also it is good quality high tensile steel and has more resilience than some commercial axles! The crown wheel is a Scalex 27z from Scalexworld and the wheels and tyres are Cartrix from a local supplier. The guide is the trusty spring loaded Ninco guide with push in lead wire eyelets. I used the tried and tested “Wixle” at the front end.

To get the body close to the track the wheels and axles were assembled in the chassis/body and the vertical posts were adjusted up ‘til I achieved a good low stance. Only the front spoiler stopped me going any lower! Happy with all the placings it was time to fix everything. I use a 40W soldering iron as it has instant heat to the touch and when soldering metal such as brass it doesn’t lose that heat and render a ‘dry’ joint. On thing though is not to take too long to solder a joint. Two seconds max or you find other things in the area coming unstuck or in the case of PCB you are at risk of detaching the copper from the resin board! If you fluff a joint, cool it and try again or move on to somewhere else.

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Well, chassis finished, time for testing. I only have a small figure eight Scaley classic track at home now so all initial testing is done on this. I always build a car so the tyres and other bits just touch surrounding parts. The reason for this is I get as close a fit as possible. Once the chassis is running then all the touching places can be sanded or Dremeled to give the minimum clearance. Tyres often lose radius when trued so this gives a clearance anyway.

The motor is an SCX RX81 (old rally motor) with the front shaft cut off (this was used to make a replacement prop shaft on a Carrera Aston Martin, but that’s another story). I chose this because the car will be used on home circuits of about 20 metres lap length and the motor has plenty of zip out of bends. The motor had the usual check out as described in Rob’s articles, and com truing and winding lacquering was also carried out. Tyres are trued, gear is bedded in with Tamiya fine paste front and rear axles lubed and off we go.

Initially, the car was a little bit skittish in the corners. A few laps were run and the outer edges of the rear tyres were radiused. More testing and the car settled down to a good corner entry speed and a clean exit. Still a bit shakey in the bends so next I countersunk the two chassis fixing screws and holes. I left the chassis screws a turn loose to help with body movement. Back on the track and the final adjustment had transformed its handling.

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Next was to test in on a bigger circuit. This was to be the 21 metre two lane board track of a good friend. As mentioned else where, in most cases, if you get a car to run well on wood it becomes a dream on plastic. This was no exception. From the very start the car was responsive and quick. The RX81 motor allows you to leave breaking ‘til the very last and once in the corner you can power out with impunity raising your straight line speed for the start of the straight. It is totally predictable and a pleasure to drive. Its overall performance puts it marginally below an NC2 and slightly better than a standard Scaley ‘S’ can on this type of track. We don’t have lap counters installed yet. That will come shortly. So until then I can only make comparative judgements.

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Body,			      left over
Motor, 			       left over
PCB                                            approx $2.00  I bought a large square 
                           200x200 from Smith’s at a sale price of $9.00  
Axles                                         50c.
Brass tube                                  50c.
Gear                                          $3.00
Guide                                         $3.00
Wheels and Tyres                       $8.00 I think?
I am very pleased with this exercise and the car has become one of my favourites, first out of the box on track nights. If only the rest of the Touring car range were as good as this, but then I’d have no challenges!
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When I'm not racing slotcars,
I'm out in the back yard, burning food!!

When I win, it's because of my talent, not my car or my controller!
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