Scratchbuilding in 1/43., A discussion thread. Options

[beardy56]

I haven't done any scratchbuilding for about 40 years and that was in 1/24th & 1/32nd scales. Now I'm going to have a go in 1/43rd scale.

This is the body I'm going to use.





This is the full kit





One advantage is the the kits chassis screws on to the body.
I don't have a chassis to fit at the moment, I have got a couple of cars , I think they art Artin, coming soon but I think they will be to short. So it looks like I will be cutting extending and gluing to make a chassis fit


Lloyd when you have some spare I could be interested in a Mk1 Cortina & 105E anglia shell.

[300SLR]

What about listing these motors ? <<the ones with magnetic down-force>>

As it seems the tracks used in this proxy are made of wood with copper tape, magnetic down-force is irrelevant to these races.
It may be off topic for this thread, but it is interesting to those running on track where magnets do work.

Slot car motors usually have some stray magnetic field.
It would be a big job to measure and list how much field each standard motor has.
It would certainly be interesting if anybody was prepared to produce a comprehensive list.

Some motors are deliberately built with a lot of stray magnetic field to provide a magnet traction. This is a way of getting round "no traction magnet" rules. This is most common in 1/32 racing, the "high down-force" motors are often S can or " long can size (about 15mm high by 20mm wide) which are a bit big for 1/43.

Where the rules say no traction magnet but don't say anything about what motors can be used, there is nothing to stop an entrant modifying a motor to produce more magnetic down-force. That would be a straight forward enough job for racers experienced in motor building. A good question is how much advantage that would give, I guess the only way to find out is to try it. Of course all this depends on what is arguably a loop hole in some sets of rules, it is easy enough for organisers to produce rules that don't have this loop hole.

[Tsooko]

Peter's track is copper tape and latex paint, hence magnets have no effect My track is Braided but not magna braid, Here's a hint: I have coated the track surface with four coats of Magnetic paint and two coats of chalkboard paint, so there is a slight and smoothly subtle magnetic pull.
If your motor has good magnets in it you can perhaps gain a small advantage but I don't think it will amount to much. I am going to say in the spirit of fairness and this first ( sort of ) proxy, added magnets not be allowed. Let's see what you can do to increase traction with the build and design of the chassis. Or tires.
You could even cast your own tires. No Silicones please.

Lloyd. WE just didn't want to discourage entries by limiting the Chassis material too much
Mas, I forgot all about aluminium! A good material to build with, for sure.

I am new to building chassis and have been studying what has worked in the past and what not. I think that a little chassis theory should be considered starting with how forces act on a moving, hopefully fast moving, car. If anybody has anything to add, please do so.

First let's move the car down a straight.
Upon acceleration the weight of the car transfers to the rear and the front end gets light as in a wheel standing drag cars. The weight is taken up by the tires and that adds to the traction. Too much traction and the guide comes out of the slot. Too little and you got a tire spinning slug.
At the end of the straight you de-accelerate and the weight transfers to the front, making the back end light.

Then we add in torque. As the motor spins, there is an equal and opposite force. This will cause the car to lift on the left side of a clockwise spinning motor looking from the back of the car towards the front, reducing traction to that rear tire. Again I point to drag cars. Sometimes this will be so pronounced that the car will go off course.The heavy wheel getting the most traction and the light wheel getting the least causing the car to torque around the axle. I call this a secondary force, which, in slot cars can probably be ignored until you are into very high perfomace machines.
Except when you are negotiating corners.

Corners: The forces on a car in a corner can be summed up in one word: Inertia!
Inertia is the resistance to change in direction, be that in forward, backward or side to side.
Let's examine what happens to a car in a corner and divide the corner into three sections.
Section one. If there is no change in speed, the car wants to go straight and will deslot when the forward speed is beyond the ability of the guide to hold the car in the slot. Gravity plays a part here, so does traction. As the car decreases speed ( brakes ) the weight transfers to the front increasing the weight on the guide helping it to stay in the slot. One other force comes into play here and that is centrifugal force. The opposite force that pulls on the car in a corner. Left hand corner, right hand force, Right hand corner, left hand force. So not only does the weight transfer to the front it also transfers to the side opposite the direction of the corner, with the most weight transferred to the front tire on the outside of the corner.
Second section. This is where we are off the brake and the car is coasting. The front to back weight transfer is neutral and centrifugal force has weight transferred to the outside tires. Weight to the tires adds traction and grip. As long as we have slowed enough the guide will stay in the slot and the car will follow it around
Third section. This is where we accelerate, transferring weight to the rear of the car with centrifugal force still transferring weight to the outside tires, the most weight being on the outside rear. Here also is where the motor torque comes into play somewhat. Remember that? The torque will also transfers weight to one side of the car making it easier to go in one direction than the other.
Managing these weight transfers is what we are aiming for. 1 to 1 cars do this with springs, shocks, torsion bars, traction bars and other magical mechanical devices.
We don't have those tools at our disposal and must do this another way. So how?
In a word: FLEX.
WE can build in Flex into our chassis allowing the chassis to twist and bend absorbing and redirecting the forces acting on our slot cars keeping rear tires flat, the guide in the slot, traction to a maximum and power to the road.

A good chassis is one that transfers weight to where it is needed most.

'nuff for now

Ted

[300SLR]

Hi Ted
That's a good explanation.
What you say about motor torque applies to inline motors - which seems to be the norm in 1/43
It works differently if the motor is mounted a different way, sidewinder for example.

What works in 1/32 has got to be a good starting point for developing quicker 1/43 cars, but I doubt its more than a starting point. (Quick 1/24 chassis have similarities to 1/32, but the detail is developed to work best at that size.) In racing, making a car really quick rather than just going fairly well is the important bit and that has mainly come from practical development / trial an error rather than theoretical analysis. A lot has been written in earlier threads about the theory of how slot cars work. Some very eloquent and well reasoned, and some of it complete rubbish. The best of it explains why a slot car works, but even the best of it says very little about the differance between a car that goes fairly well and one that is really quick.

[Lloyd.L]

It is all very well having a car that is really quick in the hands of it's builder, but for proxy racing, a well mannered car that will lap consistantly in the hands of any driver will have the advantage on longer stints. So it also depends on how many laps each car is to be timed over.

[300SLR]

It is all very well having a car that is really quick in the hands of it's builder, but for proxy racing, a well mannered car that will lap consistantly in the hands of any driver will have the advantage on longer stints. So it also depends on how many laps each car is to be timed over.

Good point - cars that are easy to drive quickly consistently are an advantage whoever is driving them, all the more so in proxy events.

Making cars easy to drive quickly and consistently depends on practical development / trial an error rather than theoretical analysis. In fact theoretical analysis is even less help in making cars easy to drive quickly than it is in making them quick.
I think experience in making a 1/32 car easy to drive quickly is likely to be helpful in developing 1/43 cars.

[masmojo]

It is all very well having a car that is really quick in the hands of it's builder, but for proxy racing, a well mannered car that will lap consistantly in the hands of any driver will have the advantage on longer stints. So it also depends on how many laps each car is to be timed over.

Very true Lloyd, I know if you took the three cars I submitted in the last scratchbuild proxy, I could move them all around the track at about the same rate, BUT they all had a different character and it took a few laps to figure out what worked best with each car. Probably my fastest car in the last SB proxy did the worst because it was more challenging to drive and the Host did not know how to get the best out of it; That's the way the cookie crumbles and I knew it going in. This is especially true when magnuts are removed from the equasion. Short wheelbase cars don't like being drifted so it's hard on the brakes into the turns and back on the throttle quick. Both of the tracks on the bill so far are tight and twisty, so a longer wheelbase car is going to need to be very tossable and very forgiving! Still it will be a challenge because Ted's Chalkboard paint is going to have WAY more grip then Peters smooth laytex!

Regarding the magnetic attraction of the motors surely there will be some, it's unavoidable, but a couple things to consider when exploiting it. Larger motor for the most part will have more, but not necessarily, second, Clearence, with a scratch build it's hard to get the motor low enough to do any good whilst also leaving enough room under the car for the guide AND if the bottom of the car is high enough to fit the guide the magnet will start to move out of it's effective range. maybe you can manipulate the mounting of the guide with a swing arm or something?

I really find it a bit amusing and encouraging that you guys are taking this so seriously this time around!

[Lloyd.L]

I'm not so scientific Mas, build it, run it on the track, tweak it. If it goes well, send it, if it doesnt, build something else.

It is interesting to see the experienced recers from other scales looking for the widest and lowest with the hottest motors. Maybe we will get to the stage of 1/43 Thingies, but for now I prefer to build interesting scale model cars and send them to proxys for a bit of fun. My 2 cars for this proxy are certainly not ultimate racers, it will be interesting to see how they get on!

Regards, Lloyd

[300SLR]

Not sure the hottest motor is a good idea.
Experience in 1/32 is that an overpowered car is slower and much more difficult to drive than one with a more appropriate amount of horsepower.
It would be surprising if that doesn't apply to 1/43, and the appropriate amount of horsepower will be less than 1/32.

[masmojo]

I'm not so scientific Mas, build it, run it on the track, tweak it. If it goes well, send it, if it doesnt, build something else.

It is interesting to see the experienced recers from other scales looking for the widest and lowest with the hottest motors. Maybe we will get to the stage of 1/43 Thingies, but for now I prefer to build interesting scale model cars and send them to proxys for a bit of fun. My 2 cars for this proxy are certainly not ultimate racers, it will be interesting to see how they get on!

Regards, Lloyd

I am with you Peter, my feeling exactly! Better to have a car that's fun to drive then crazy fast and no fun to drive, the race will be over fairly quickly, but hopefully you will be driving whatever you build for many years!

Not sure the hottest motor is a good idea.
Experience in 1/32 is that an overpowered car is slower and much more difficult to drive than one with a more appropriate amount of horsepower.
It would be surprising if that doesn't apply to 1/43, and the appropriate amount of horsepower will be less than 1/32.

It very much does apply probably more so! Concerning your Ford GT, I have built one of those already, I think you should look for a Compact SCX chassis! It fits well, i don't remember if I had to cut it at all, but I am guessing I did.

Keep in mind that a Compact or GO! or ARtin chassis is not eligible for the proxy race! Might try sheet styrene, It's a good material for building 1/43 chassis and easy to work with!

[masmojo]

I thought I would post this list; It's a list I compiled several years ago and it is incomplete and may have a few boo-boo's, but it might give some Idea of whats available out there!

I should emphasize that his is just styrene static Model kits!
If you add Resin Kits and convertable toy cars from folks like Norev, the sky is the limit

Academy
2010 Mustang GT
Lamborgini Super Leggera
Lamborgini Reventon
Ford GT

AMT/ Matchbox
67? Corvette
69' Corvette
36 Ford Coupe
69 Chevelle
48 Ford Coupe
69 Mustang Fastback
57 Chevy Belaire
1969 Ford Torino
69' AMC AMX
Jaguar XKE/ E-type
67' Plymouth Baracuda
69' Camaro SS 396
68' Pontiac Firebird
67" Mustang Fastback
Pontiac GTO
Volkswagan Beatle
Ford GT40
Mercury Cougar
68 Ford Thuderbird
69 Mustang 2+2


Bandai
Nissan 300 ZX (prepainted in several different liveries)
Lexus 430 (prepainted in several different liveries)
Nissan Skyline Vintage (year?)
Nissan skyline Modern (year?)

Entex (actually a little larger 1/39 and made out of a very thin and fragile styrene)
Lamborghini - Jota
Lamborghini - Silhoette
Ferrari 512BB
Porsche 935
Lancia Stratos

Heller
Benetton F1
BMW 630CS
Mercedes Benz 450SL
Volkswagon K-70
Citroen 2CV
Citroen Traction Avant 15CV
Citroen DS 19
Porsche 962
Jaguar XJR9
Peugeot 905
Leyland Princess 2000
Lotus F-1
Land Rover
02' Subaru Impreza WRC
01 Ford Focus WRC
00' Subaru Impreza WRC
Renault R5 turbo
03' Peugeot 206 WRC
04' Peugeot 307 WRC
Peugeot 403
03' Citoen Xsara WRC
Mercedes C9
Citroen ZX Rally
Renault R20
Lancia Esso (Integral ?)
Williams F1
Peugeot 205 Turbo Paris-Dakar
Renault 4CV
No 180 Citroen CX2000
No 181 Range Rover
No 183 Jaguar XJS
No 184 Austin Mini Spe'cial
No 185 Leyland Rover 3500
Porsche 928
Alfa Romeo Alfa-Sud
Renault 30TS
Peugeot 203

Gunze
Peugeot 203
Jaguar XJS

Monogram
(Ultimates)
Shelby Cobra
Corvette convertible (67?)

Nitto
(Old kits long out of production)
Chapparal
Toyota 2000GT
Lotus Europa
(and a couple more that I could not make out on the sides of the boxes)

Rosso
Acura NSX
And a couple more I do not remember at this time.

An enterprising person can scrounge up all of these up easily in just a few months, I have all but the AMT Cougar.

I spent years hunting for 1/32 model kits to convert and never really found 1/3 of this amount and when I did 60% of the time they really weren't 1/32 scale (some were not even close)

Hope this helps some people who may have been on the fence before!

[Slotracing Al]

Better to have a car that's fun to drive then crazy fast and no fun to drive, the race will be over fairly quickly, but hopefully you will be driving whatever you build for many years!

How are the proxy competition points awarded?
Something like points for concorse and points for the laps covered in the racing? No points for being fun to drive?

Looks like one of the main aims is to build a car that looks as good as possible.
Looks like the other main aim is to build a car that most drivers can easily drive to the maximum number of laps.

Fun to drive but slow is probably easier to achieve, but how much use is that if the other cars do more laps?

[pfuetze]

Al, in the proxy races i participated, the normal scoring was done for the average lap time. 30 timed laps, the 5 slowest lap got skipped, the other 25 laps divided by 25. lowest time was winner. maybe done on 2 lanes and also averaged.
so you got to build a fast car that would be quite easy to drive for the host, but still fast.
Peter

[Datto]

So no printed chassis.. I'm out

[pfuetze]

where did you read that, Marc?
so also this thread: http://www.slotforum.com/forums/index.php?showtopic=62323