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The Mac Pinches Thirties Championship

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Its with great pleasure John and I announce the 2020 Thirties proxy series. Read on to find out about the rules, timescales and races.




In remembrance of Mac Pinches we have re-named the Thirties Proxy ‘The Mac Pinches Thirties Championship’. This has the approval of Mac's daughter Tina.


The 2020 proxy is run to the following rules and whilst they are similar to those of the 2019 event, there are some differences so please read carefully.


Entry Notification


Entrants should notify John Warren and David Mitcham of their intention to enter as soon as possible with an indication of the number of cars and the make of car - particularly if they intend entering a Mercedes or Auto Union - see Choice of Car below.


Car Receipt Date


All cars must be with the first round organiser by 1 May 2020. The postal address will be notified to entrants in due course.


Entry Fees


An entry fee of £30 for one car and £15 for a second car will be required payable by 28 February 2020. The fee will be used to cover postage costs between venues, international shipment, for the return of cars to entrants and to cover the cost of prizes and trophies.


Car Identification and Packaging


Each car must have the name of the entrant marked on the chassis. Cars should be sent in strong, reusable packaging and a return label must be included.


Number of Cars


The number of cars will be limited to 30. Once that number has been reached a reserve list will be opened.


Choice of Car


The eligible cars for the proxy are Grand Prix, Indianapolis, Brooklands and Voiturette cars that competed or were built, but not necessarily raced, in the years 1930 to 1940. Record cars and streamliners are not allowed.


In order to encourage variety and to avoid a grid full of Auto Unions and Mercedes the number of cars of those marques will be limited to three of each. Any entrant wishing to enter an Auto Union or Mercedes must notify John Warren and David Mitcham as soon as possible and the 6 places will be allocated on a first come first served basis.


An entrant may enter up to two cars.




Body dimensions must be 1/32 scale + or – 1mm.


All body shells must be of hard plastic, glass fibre, resin, wood, metal or similar material. Vacuum formed bodies are not permitted.


All cars must be finished in a style sympathetic to the period being represented and carry at least two racing numbers. Duplicate numbers will be allowed but note that duplicates will have letter suffixes added by the organisers so that each car can be uniquely identified.


All cars must have a suitably decorated and period correct, 3 dimensional, representation of a driver consisting of at least a head, shoulders, arms, hands and the upper part of a steering wheel.


All cars must have clear windscreens fitted where they appear on the prototype.

Vacuum formed windscreens etc. are permitted.


The body must be solidly fitted to the chassis in such a way as to truly represent the prototype car, it must not appear to be lowered.


Body float or rock is acceptable.


Fixings to the chassis should not be visible above or to the sides of the body.


All body fixings must be secure and not become loose or drop off during racing.


The chassis, motor and all running gear must not be visible from above or through the cockpit opening and engine bay unless that which can be seen represents parts of the real car. Suspension components and exhaust systems for example.




Any material list here can be used to construct a chassis…brass, wire, plastic, nylon, wood, steel, PCB board, 3D printed.




The wheelbase measurement must be set at 1:32nd scale, plus or minus 1mm


Maximum Width


The maximum width of a car must not exceed the following:


GP, Indianapolis and Brooklands cars: 53mm: Voiturette 50mm. The measurement is tyre bulge to tyre bulge across the front or rear axle depending on which is the widest.




Can be brass, oilite or ballrace.


Ground Clearance


From the bottom of the chassis, including ballast and screw haeads, to track surface at any point:


Grand Prix, Indianapolis, Brooklands Car: 4mm Minimum


Voiturettte Car: 3mm Minimum


Guide Choice


The slot guide must not protrude beyond the front-most point of the car when in the straight ahead position and viewed from above. Black in colour only. One guide per car.




Voiturette - up to 20K rpm commercially available FF or FC type motors.


GP, Indianapolis and Brooklands - open choice of commercially available motor.

Rewinds and any other motor modifications are not allowed.


Motor Alignment - In-Line only.




Any wheel and tyre combination but must give a true representation of the original (i.e. no low profile or inappropriately narrow tyres). Appropriate period style 3D inserts must be fitted.




Tyres must be rubber or urethane and no treatment to the front or rear tyres is allowed including hard coating the front tyres. Tyre dimensions are as follows.


Front Tyres - Overall diameter and width of wheels and tyre must be:


GP cars Min Diameter 21.5mm with a max width of 6mm.


Voiturettes Min Diameter 21.5mm with a max width of 6mm.


Minimum contact patch and minimum width 4.5mm


Rear Tyres - Overall diameter of wheels and tyre must be:


GP cars minimum diameter 23.0mm with a maximum width of 7mm.


Voiturettes minimum diameter 22.0mm with a maximum width of 7mm.


Contact patch 5.5mm.


Tyre widths are measured bulge to bulge not contact patch.


Other Components


Glue & True tyres - yes


Axles - Free Choice


Gears - Free Choice


Magnet - No


Ballast - Free Choice


Race Format


Cars will take part in official practice to determine 'grid positions'. Using the same lane, each car must complete 5 laps. The best lap time from the 5 laps will count as official practice lap time/grid position.


On race day cars will compete in each heat according to their practice times, eg fastest four cars in the first set of heats, 2nd fastest four the in second set of heats etc.


Finishing order for each round, will be determined by distance covered, based on laps within a set amount of time. A minimum of 3.00 minutes racing time per car, per lane is required at each track. Maximum distance covered will be recorded after each heat.


Hosting tracks will be required to accommodate a measured lap distance (dividing lap distance into feet or metres) to determine accurate finishing distance in order to establish distances of cars completing races on the same number of laps.


The fastest lap for each car will be recorded. In the case of two or more cars being tied on the same number of laps and parts of a lap their fastest laps will be used to determine their finishing order. If a tie still results then their respective qualifying lap will be used.


Lane and driver rotations to be to be managed by event host.


Sprint Format


For sprint events each car will take part in official practice as described above and will then complete two rounds of at least 20 laps. The total aggregate time taken to complete them will determine the finishing order of the cars. The practice times will determine the running order of the cars - the fastest car running first and the slowest last in the first set of 20 laps and slowest car from practice will run first in the second set of 20 laps and the fastest last.


In the case of two or more cars being tied on the same aggregate time their fastest laps will be used to determine their finishing order. If a tie still results then their respective qualifying lap will be used.


The fastest lap for each car will be recorded.


General Event Conditions


Hand controller/throttles types at each venue will be left to the discretion of the event host.


Tyres will be cleaned before each race using either water and/or tape but no chemicals, solvents or lighter fluid will be used.


Track voltage will be between 10 and 12 volts at the discretion of the host and will remain equal for all lanes throughout an event.


A running inspection of cars will be made before and after each race. Cars may be cleaned and lubricated. No penalties will be incurred for repairs required to keep the cars in the race. This excludes tyre and motor changes. If a motor should fail during qualifying or during the race it can be replaced after the race has been completed without penalty at the entrants expense. Before repairs to any damage to the body or chassis are made, the track host will discuss with the car owner for repair or return instructions.


Track hosts will provide a report from each round with photographs and the detail of each car’s performance in terms of laps completed on each lane and in total, fastest laps and in the case of sprint event the time to complete the 20 lap segments and aggregate time. The points awarded will also be recorded. The proxy organisers will provide championship points up-dates after each round.




The cars will be scrutineered before the first round as to their compliance with the rules. If a car fails scrutineering the entrant will be contacted and the modification required will be discussed. Where non-compliance with the rules is major, eg the motor is outside the rules, or the tyres are too small or too wide, or the wheelbase is incorrect, 10 points will be deducted from the car’s points score at each round. If non-compliance is minor (ie not potentially performance enhancing) it will be at the discretion of the organisers as to whether the car is allowed to compete as it is or whether modification is required.


Points Scoring


The points scoring for each round will be as follows:




Fastest lap of the race will receive a bonus of 2 points.


In the case of a tie at the end of the proxy a count back system will apply. If two or more cars finish on the same points then the car with the most wins will be declared the winner. If still tied then the most second placings will apply and so on and so on down the finishing order. If after that we still have a tie we will determine which car had faster lap times on the various tracks.




It is anticipated that there will be eight rounds of the proxy, four in the UK between May and August and four in North America between September and November. Details will be announced in due course.


Technical Data


Each entrant will be required to provide technical details of their car, or cars, which will be published on the Formula One Thirty Two Scratchbuild Forum, SFI and Homeracing World. The data required is as follows:


Car Type/make

Car Number

Body maker and material

Chassis construction and material

Gear make and ratio

Guide make

Tyre make and material front and rear

Wheel make front and rear

Motor make and type



Photographs will be taken of all the cars prior to the first round and published on the forums mentioned above.


Each car must have the entrant’s name or initials permanently marked on the bottom of the chassis. This is essential in an event where there are likely to be duplicate car numbers and makes and types of car.


Sending Cars to the Organisers


It would be very helpful if entrants would notify the organisers – John Warren and David Mitcham when they have despatched their car or cars to David for the UK rounds either by PM or a post on the Formula One Thirty Two Scratchbuild Forum, SFI or Homeracing World. Please include a return label with your car.


Concours d’Elegance


The cars will receive votes/points for Concours d'Elegance from the host, drivers and marshal's in attendance at each round. Each car entered will receive points out of 100 based on accuracy, build quality, detail and finish. All the cars will be judged together and there will be one Concours prize. The Concours results will standalone and will not be added to the racing results points.


Best Regards


David Mitcham and John Warren






John Warren

Slot cars are my preferred reality

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If you are allowing new entrants, I'd love to have a crack, someone's got to do the mopping up at the bottom of the table and I'd like to be that somebody.


May I enter 2 cars if I can source a Maserati 6CM body.

Otherwise just one with an Alfa 8C.


Assuming this is on SCI I will post once their website is back up and running.




Found a 6CM body.

So two cars please.

Edited by ZeGas

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Hi Zegas, I will put your entry into the database.

There wont be anything on SCI but you could follow it more closely on SFI(recommended) or HRW(new version) or on One thirty two formula one scratch build forum.

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