Welcome Guest ( Log In | Register )

 

On magnets and weights in slot cars

by Andrew Rowland 

Premise:
That ‘modern’ slot cars are sold with magnets in the base and that these magnets affect the performance of the car.

Problem:
First I should explain that I am a ‘collector’ of F1 slot cars, particularly but not exclusively those made by SCALEXTRIC. Second I am particularly interested in both original and ‘reproduction’ cars, these last often called ‘vintage or classic’ from the 1950’s and 1960’s.

This study is directed specifically at ‘classic’ F1 models marketed by Scalextric (SX) in the last few years, although it may be that some or all of the results would equally (and possibly more easily) be applied to Saloon type cars too.

My belief is that the magnets inserted by the factory in these cars cause undesirable results in several ways:

a) they remove almost all of the hand eye coordination required with traditional models
b) they remove therefore almost all of the ‘feeling’ and skill which is a big part of my attraction for this hobby
c) the cars move so rapidly that one cannot actually see their beauty or their ‘position’ on the track
d) any idea of replicating the ‘sliding’ behaviour of the original cars and consciously controlling cornering is removed
e) since the car is moving so fast any crash occurs at such high velocity that the car risks extreme damage (especially considering the extreme fragility of the new models (see more on this below)
f) since different companies have different types, sizes, positions and strengths of magnet it is very difficult to race for example a CARTRIX Gordini against a SCALEXTRIC Vanwall, whereas in fact they should be contemporary cars
g) The performance is so related to the magnet it is almost impossible to make any two cars have similar performance in real terms making ‘competition’ difficult

So the first thing I did was simply remove the magnets, but sadly that didn’t have the desired affect. These cars (I speak now exclusively about the SX ones) were clearly NEVER tried or tested or indeed intended to be used without the magnets. Which is a great pity since it really doesn’t need much work or study to either reduce dramatically the strength of the magnet so that the cars still have most of the above desirable characteristics or, even more simply, to make them heavier so they perform much like the original cars.

Take for example the CARTRIX cars, their magnets are subtle and make a much reduced degree of difference, allowing ‘tuning’, not total change to performance.

More importantly still CARTRIX magnets are easily removed and replaced without causing any potential damage to the car, something that it is very, very difficult to achieve with the SX models which are so complex and fragile that after I had taken out the magnet (which necessitated taking out the motor and therefore in turn the rear axle assembly) doing this only once had caused stress fractures to appear in the axle mounting clips meaning I am now loathe to ever take the model apart again since I risk breaking it.

Whilst I appreciate these models are ‘scale’ rather than full ‘racing’ and that they are sold primarily for their fine detail and not their strength, it still seems to me incorrect to sell something as a ‘functioning’ electrical toy with screws holding it together (and not simply glued) that cannot actually be taken apart without terminal damage being done to it. These new cars seem to have been made with a very brittle plastic and the forms are far thinner than in the past and these factors don’t seem to have any logical reason that I can see.

Anyway this study is of another type, so to continue……

Study Title:
What I set out to check was whether weights could be used to ‘replace’ the magnets in new ‘classic’ SX cars in order to overcome the above ‘problems’?

More specifically I was interested in whether the performance change brought about by weights was in some way ‘predictable or tuneable’ in order that different models could have ‘similar’ performance in order that they could compete against one another.

As a study I have chosen 7 cars. These are split into 3 groups for the purposes of the test:

1. 1955/6

i. Mercedes W196 (CARTRIX)
ii. Gordini T32 (CARTRIX)
iii. Vanwall (SCALEXTRIC) (Goodwood sport version)
iv. Maserati 250F (SCALEXTRIC) (Goodwood sport version)

2. 1976

i. McLaren M23 (SCALEXTRIC) (year of legends twin pack)
ii. Ferrari 312 B2 (SCALEXTRIC) (year of legends twin pack)

3. 1968

Lotus 49T (TECNITOYS / SCALEXTRIC) made up from blister packs released in Spain

Group 1.
This is the subject of the real study since I wish to race these 4 cars together on a large digital track (that of Graham Lane of Mini Mille Miglia fame). Since each car has such utterly different performance I want them to be competitive together.

(Three of the four have been chipped but the Maserati 250FI have found impossible to locate the chip inside without damaging the driver, something which I am currently loathe to do. I would be interested to hear from anyone who had indeed managed this, to understand how it might be done. In fact I also have the tinplate version and this I have managed to chip so I may end up using that to complete the set of four.)

(Sticklers for authenticity will tell me that actually the Mercedes 196 never raced the Vanwall 56/57 but since I’m English, I live in Italy and have German friends I like the international nature of these four cars on the track and it is only 1 year…...)

Group 2.
Lovely cars but with the magnets they go way too fast, and without they go slower than the 1950’s cars from Group 1.!

Group 3.
I’m awaiting the Eagle Weslake for some racing but in the meantime NEED this car to have some sort of driveability. Without the magnet its just about the worst car I’ve ever ‘driven’, sliding all over the place and being almost completely uncontrollable.

This seems to be mainly due to the tyres and the extreme lightness of the model.

Notes / Assumptions:

Tyres
It is my opinion (and I’m surely not the first to notice!), that the single most important thing affecting performance of these cars is the tyres.

So pitting the CARTRIX against the SCALECTRIX in Group 1. is already hard since the SCALEXTRIX cars obviously have scaled tyres while the CARTRIX R’n’D dept. obviously decided that the performance needed to be enhanced and so gave their cars tyres that are slightly wider (and softer).

More than just width or diameter however the fundamental thing is the compound, the material or the softness. I’m not an expert on this so I cannot say whether the two companies tyres are indeed a different material, however what I do know is that despite the two SX cars being of exactly the same wheelbase, track and almost the same weight and also given they are both Goodwood revival cars of the same limited edition I would expect them to have the same tyre compounds.

Actually I was quite a long way into my study before I realised that the tyres on the Maserati were much harder than those on the Vanwall and that is what had always made them so different to drive. This really pissed me off frankly! It meant however hard I worked on my results for this study I will never be able to race those cars together since their performance is so different. In fact the Maserati, without the magnet is almost as undriveable as the Lotus 49!

I actually ended up using only the soft tyres (originally from the Vanwall) and changing them between the two cars for the study, but is it only me that thinks it is totally ridiculous that two cars have two different tyres?

Build quality / fragility of the models
I just want to note, in case anyone useful is reading this, that the construction quality of SX cars is dreadful. Apart form the fact that they virtually break the first time you take them apart and their tyres are not consistent, when I took apart the Ferrari 312 T2 I found that the magnet was actually broken despite it being in place. It was definitely not broken by my using it (I did about 5 laps to check the speed with magnet before taking it apart) so it must have been broken either in manufacture or transit which is simply ridiculous.

Track type / length affecting the relative performance of each car
Obviously my track is pretty short having only about 35 pieces and the relative performance of each car type would differ with different track types. For example, a very simple track of large curves and long straights would reduce the importance of cornering inertia as a percentage of the time needed for a lap compared to a very windy track devoid of straights.

All I can say on this is my track is what one might call ‘average’ with some R2 curves and one ‘long’ straight, so I suggest my findings are a good base for others to follow in most cases.

Variation between models / real cars
Obviously two cars are never the same, either slot cars or the real ones they emulate so it is never necessary that two cars racing together have exactly the same performance. However, for any kind of interesting race to take place if the cars are totally mismatched then the same car will always win. Perhaps my sense of ‘fair-play’ will not be shared by everyone but I prefer that the cars are almost equal so that the driver makes the difference.

Having said that I nearly always lose but again as someone once it’s the competition that is important not the winning.

Car Weights and speeds
Just as a ‘control’ I note that without magnets the original C62 Ferrari 156 (sharknose) on my track does a lap of 3.6 seconds (round pin guide type), while the ‘new’ one (without magnet) does only 4.4 seconds. The C62 weighs in at 90gr, while the new one only weighs 51gr.

This gives some idea of how the much lighter newer cars despite all the modern guides, motors etc. don’t actually necessarily make for better performance.

Track changes
Between Group 1. and Group 2./3. I changed the track very slightly so the times are not comparable between groups.

Timing
Timing is only to 1/10th of a second since I am using a 1990’s ‘pole position’ oral timer. It would be clearly advantageous to have a more precise method of timing to aid precision in calculation.

Lap times
Lap times were not averaged over many laps. I took each car and did about 10 laps only in order not to attune to any one car and therefore keep a parity of result. Obviously therefore the results are comparative but not ‘absolute’.

The Study:
First I weighed the cars without magnets (I termed this ‘dry weight’) and then I weighed them with the magnet ‘acting’ (magnetic weight) in order to understand the increase in weight caused by the magnet. (See method below). I also ‘raced’ them around my test track in order that I had speeds for both dry and magnetic weights.

As a control I also raced a few original SX cars to try to understand what sort of lap time might be ‘fun’ and reasonable as a target. Obviously this ‘desired speed’ is in some way subjective but actually there are several things dictating that speed:

a) It has to be ‘between’ the fastest dry car and the slowest magnetic.
b) Since the study is meant to overcome points a) to f) above it is quite simple to decide what the speed might be.
c) If one also wishes to race original cars against new, the lap times of the original might be used as a guide, plus presumably one should assume that performance should have increased over the years so if a lap time of say 3.4 is gained from a mid 1970’s Grand Prix car with slicks etc. the cars I’m trying should be somewhat slower than that.

I originally decided my desired lap time would be 3.9seconds, although later this was changed to 4s as I realised that 3.9s was not achievable by some of the cars. Below the tabulated times are therefore quoted at 4.0s while some of the early results regarding the Vanwall were based on achieving the 3.9s lap.

Using a simple spreadsheet I worked out the ratios of weights (dry to magnetic) and the lap times (again dry to magnetic) and assuming a directly proportional relationship between weight and time this allowed me to calculate the weight of the car at any lap time I chose.

Of course (as was immediately pointed out to Graham when he aired my idea on the Forum) this is very simplistic, given that, it doesn’t allow for inertia. In fact, as I will explain below there are other things it doesn’t consider too, which are also fundamental to a car’s lap time.

Initial Data Collection:

Car Dry weight Magnetic Weight Dry lap time Magnetic Lap time
  (gr) (gr) (s) (s)
Group 1.        
Maserati 250F 56 110 5.4*** 3.0***
Vanwall 56/57 61 110 4.5 2.8
Mercedes W196 50 65 3.9**** 3.3
Gordini T32 53 68 4.0 3.3
         
Group 2.        
Ferrari 312 T2 61 204** 4.6 2.2
McLaren M23 60 188** 4.4 2.2
         
Group 3.        
Lotus 49T 49 110* 4.6 2.7

* predicted by reference to other models since to take it apart and insert the magnet would almost certainly have caused terminal damage to the axle mountings.

** in practice I assumed an average of 196gr for these two models since one had a broken magnet and was probably showing a spurious reading. This might have been a wrong assumption since the Ferrari may have been intended to have a more powerful magnetism to overcome its reduced rear end track width.

*** these times were taken with the infamous ‘hard’ tyres and since I was not going to take the risk of dismantling the motor again to put the magnet back I had to ‘extrapolate’ the results for calculation use.

**** it should be noted that this lap time is BELOW the desired result of 4s. This has been ignored for the purposes of the study so that this car is assumed to perform at the desired 4s and left as is. If it is seen that this car is too consistently quick I may add weight to the nose to reduce rear end traction.

Adjusted Data Used for calculation:

Car Dry weight Magnetic Weight Dry lap time Magnetic Lap time
  (gr) (gr) (s) (s)
Group 1.        
Maserati 250F 56 110 4.8 2.8
Vanwall 56/57 61 110 4.5 2.8
Mercedes W196 50 65 4.0 3.3
Gordini T32 53 68 4.0 3.3
         
Group 2.        
Ferrari 312 T2 61 196 4.6 2.2
McLaren M23 60 196 4.4 2.2
         
Group 3.        
Lotus 49T 49 110 4.6 2.7

The consequent final weight predictions for a 4s lap time, together with the amount therefore required to add are thus:

Car Dry lap time Required Weight Weight to add
  (s) (gr) (gr)
Group 1.      
Maserati 250F 4 85 29
Vanwall 56/57 4 71 10
Mercedes W196 4 50 0
Gordini T32 4 53 0
       
Group 2.      
Ferrari 312 T2 4* 95 34
McLaren M23 4* 85 25
       
Group 3.      
Lotus 49T 4* 60 11

* one should recall this 4s represents a better performance in real terms than Group 1. since the track had by now been lengthened by around 4% and a ‘chicane’ curve added meaning that these cars would need to be better for the same lap time than Group 1.

Method

I simply took some roofing lead of 1.5mm thickness and cut it up with cutters to the desired shape. Where necessary to achieve more precise shaping I used a scalpel but any craft knife would work adequately.

For the Lotus 49 I also used other tools (see below).

Group 1. test Results

Vanwall:
I began with the Vanwall (since 10gr seemed pretty easy to add and since I love it and wanted to see it perform.

Since the car is chipped it wasn’t easy to fit weight in, however I managed to try different solutions all the way up to 99gr (an addition of 38gr!).

Assumptions:
My general ‘A’ level physics suggested to me that for the weight to act on the rear tyres it should be set ‘behind’ the half distance between the axles (otherwise it would act partly also on the front tyres which I didn’t think would be advantageous), and in fact as close to the rear axle as possible.

Further I thought that putting the weight behind the rear axle was going to make the rear want to rotate out since it would create a larger ‘moment’ in respect of the pivot point of the car (the guide).

Thirdly it is generally acknowledged that the weight should be as low as possible to help prevent the car ‘toppling’, through raising the centre of gravity.

Several solutions were tried and the results were:

Overall car weight (gr) Lap times (s) Position of extra weight
77 4.1 only side weights (16gr)
81 4.1 additional weight around driver
83 3.9 side and 6gr low in rear
88 4.0 side and 11gr low in rear
89 4.1 side and 12gr high in rear
99 4.1 extra 10gr in driver’s lap
99 4.1 extra 10gr by engine in front half

Obviously I have listed them here in order of weight in order that a pattern emerges although in reality the tests were done rather more randomly than that until the best result was achieved.

Conclusions to Vanwall test:
Several things became immediately obvious:

a) My assumptions about optimum weight position listed above were correct; i. weight should be centred on the rear axle if possible, ii. weight should be as low as possible, iii. weight should not be too far back or high in the tail as it causes the tail to swing out and, iv. weight in the front half of the distance between the axles does not improve performance.
b) There is quite a small limit as to how much the overall performance can actually be improved. The best solution only gained 0.6s a lap on performance. The magnetic lap time was still 1.1s quicker than the best weighted lap time. This meant that my desired lap time really had to be in quite a narrow window and I became worried that it might be impossible to bring the other cars ‘in line’ with the performance of one another.
c) This also revealed that the magnet really is an optimum way to improve lap times in these ‘scale’ models of 1950’s cars if that is what one wishes to do. What I mean is that SX and other manufacturers have a real problem to make these models driveable. I’m not fully back tracking here since the magnet (at east not those that are fitted) is still not in my opinion the answer, but simply it is also evident that simply increasing the weight is not either.
d) The inertia problem of cornering was predicted by others as stated above. Actually however as the models got heavier (excluding those that were top or tail heavy), although I acknowledge that this affected hugely the lap times, it didn’t in my opinion adversely affect performance. What I mean by this is that taken at a scientific level this is a factor but since I want something driveable and with ‘feeling’ the sliding characteristics on the corners and the need to slow down not felt with the magnet was actually great and just what I’d been looking for.
e) What I hadn’t predicted (but is now obvious to me) is that increasing the weight dramatically reduces the braking affect before corners in a way that the magnet doesn’t. The magnet, acting only as a vertical force actually aids breaking, through friction while adding weight increases massively the momentum of the car on the track and means that one has to stop accelerating way before the curve. In fact that is why as the weight increases the lap times begin to retard rather than keep getting quicker. It was found that the motor was plenty powerful enough to ‘pull’ the extra weight but that the car couldn’t be stopped!
f) There is therefore a sort of ‘bell shaped’ curve of performance against weight whereby adding weight is not useful. Detailed tuning around the best time achieved could have taken place but since the 3.9s had been achieved this was deemed unnecessary. Also since I was only working to 1/10th more detailed tuning was unlikely to give really trustworthy results.

Obviously point e) could at least partially be overcome through the use of a tuneable controller of the ‘Slot.it’ type whereby the braking could be set to maximum however this is beyond the scope of my simple study.

Overall it became immediately clear that my initial calculations were nothing more than a starting point, so from the point of view of the initial supposition that weights could be used in a predictable way to ‘simulate’ the magnet it was clear that the experiment was not a success, however from the point of view of driveability the car really had been transformed.

In a subjective sense:

a) the car in the 83gr form felt more ‘solid’ on the track
b) it ‘drove’ itself forward having enough weight to make it ‘run’ through the corner but not so much that it didn’t brake or that it flew off
c) it had good traction at the rear making it very responsive to acceleration and allowing one to ‘learn’ its performance characteristics in order that one could ‘race’ it through a series of curves / straights

It was seen that this performance window really ‘popped’ for me at 83gr, although one should consider that this is always a 1950’s car of very narrow track with 3mm wide tyres so it should be borne in mind that this car will never handle like a modern F1 with wide slicks.

Drivers used to another kind of car might still take a while to adapt to this kind of driving.

One final point to consider is that the original Vanwall C 55 (round pin) will do a very similar lap time with its old RX motor, pinion and drive cog but with new tyres, which in my view shows how fabulous those old cars were and how all the advances in technology haven’t actually got us forward very far!!! (Here it should however also be considered that the original car was actually about 1/30th scale not 1/32nd making the track, length, tyre width etc. rather larger and therefore the car is consequently easier to drive.)

Maserati 250F:
Through a similar weighting exercise I managed to reduce the lap time from 5.4s to 4.5s by adding almost exactly that predicted in the calculation.

For the record this was 17gr on the flanks, 4gr behind the driver and 8gr in the rear, making a total weight of 84gr against the 85gr prediction.

I was immediately disappointed that the lap time was still some 0.5s above the expected 3.9 / 4.0s.

It was only at that point that I stepped back and questioned why two cars with the same wheelbase, track and almost the same weight had such totally different performance levels. It was then that I noticed that the tyres were quite simply of different colours and on inspection therefore of different compounds.

This upset me quite a lot and after I swapped the tyres over and tried the Maserati with the soft tyres it immediately went 0.4s quicker per lap, lowering the time to about 4.1s.

Conclusions to Maserati Test:
Being a pit fed up (the weights no longer mattered since I would never be able to race the two cars with different tyres) I sadly abandoned further weight experiments with that model but feel that a few more laps would probably have lowered the time to 4.0s and further tuning up or down would have achieved parity with the Vanwall.

The only other thing to note is that the long tail and height of the available space on the Maserati means that extreme car needs to be taken not to put too much weight there to avoid the car being too ‘tail happy’.


Mercedes W196 & Gordini T32:
Since these ‘dry’ had already achieved the projected 3.9s/4.0s lap time no work was required, however it should be noted that these Cartrix cars are made so open internally that adding and fine tuning weight would have been very easy. In fact had it not been for the fact that the Vanwalls optimum performance was achieved at 3.9s it would have been interesting to push these models down to say 3.6s lap times and one day I might indeed attempt this. It would be interesting to hear from anyone who has already tried this.

Group 2. test Results

McLaren M23:
Given the relative ‘smallness’ of the available space in this model I started with this rather than the Ferrari, in order that I could set the lap time benchmark with this and then copy it with the Ferrari.

Thinking back this wasn’t necessarily clever since the Ferrari was quite a lot slower and more difficult to control probably due to its much reduced rear track.

Anyway, I managed to pack in 20 of the predicted 25gr necessary and this brought the lap times down from 4.4s to 4.1s, a big improvement although not sufficient to compete with the original ‘contemporary’ SX models, but at least representing a better lap time than the 1950’s cars.

The slightly modified and extended track was deemed to be about 0.3s longer than the old one such that the original 4.0s lap time was now about 4.3s. Consequently these cars were lapping about 0.3 / 0.4s quicker than the 1950’s ones in Group 1. a minimum when you consider their low centre of gravity and wide tyres (I assume aerodynamics not to have much affect at this tiny scale).

How this was achieved can be seen in the photo and this represents about the maximum achievable without removing the motor (again) to put lead in where the magnet was although I would recommend anyone taking out the magnet to do this at the same time so as not to have to remove the motor twice which is a major hassle and risks destruction of the extremely beautiful but delicate detail.


Ferrari 312 T2:
Having got the 4.1s lap from the McLaren the challenge was to match it with the Ferrari despite its much reduced rear track. (In the original the McLaren was 1.65m wide and the Ferrari only 1.45m!)

This wasn’t actually that difficult and necessitated 25gr of the 34gr prediction to get down to 4.0s.


Group two Conclusions:
In general then I would say that my predictions were more accurate for these two cars of Group 2. than for any other group and this might be because they have the most simply balanced (meaning modern) design. What I mean is that with the 1950’s cars and the Lotus 49 there are probably other forces which come into play more easily such as tyre width and compound, car width etc., while these cars are relatively well balanced from the outset and simply need a little weight to get the rear wheels to grip.

My only final comment on these is that they still handle like dogs! They sound dreadful (all rattling along, probably due to the front wheels being located separately) and slide all over the place.

Again, I suggest that the tyres are simply not up to the job without the magnet pulling them down hard onto the track.

Finally I noticed last time I took off the top body part that the motor ‘airbox’ has a large empty space in it which sits pretty close to the rear axle (at least as close as much of the weight which I have added until now), so think it might be a good idea to fill that up with lead.

It wouldn’t be impossible to match this increase in the Ferrari as there are still untapped cavities inside there, so it might be possible to get those times down and the handling up.

If anyone wants to try and let me know I’d be happy to hear about it………

Group 3. test results:

Lotus 49T
Obviously to call this a group is an exaggeration however it was intended by the time I wrote this to add the Eagle Weslake but since it hasn’t arrived yet this is a group of 1!

Actually I should also say that I had (and still have) the intention to weight the Ferrari 156 Sharknose and the Cooper T53 but that their dimensions and the difficulty therefore of adding weights has put me off a little, however the challenge of the Lotus 49T was simply too much, especially after the gauntlet was laid down by the initial response to Graham’s posting on the Forum.

Following the experiments with the other 4 cars above I had become somewhat adept at ‘knowing’ what was required so less experimentation was going to be required here. That said this model offers ‘special’ problems due to the fact that the monocoque really has been made just big enough to accommodate the motor and driver (just like Colin Chapman designed the real thing!).

Initially I played with taping weights to the underside of the body since there is about 1.5mm of space all the way along (except where the magnet housing and the gearbox poke down). This was actually a good starting point as it enabled me to test various weight quantities and distributions rapidly, something impossible with the other models since they have to be reassembled every time to test them.

Again several solutions were tried between 6 and 17 gr. It should also be remembered that the initial weight addition prediction required was 11gr.

Solution 1
First a weight of 6gr was placed under the ‘engine’ which was shaped to go along the side of the gearbox. This was a start but gave nothing like the desired traction with those wide treaded tyres.

Solution 2
Next a weight of another 6gr (total now 12gr) was added in front of this but since this added weight principally to the front tyres while it did create more stability in the car generally it did not actually achieve obviously better lap times.

Solution 3
In this solution I remade the first weight with a hole cut in it to sit around the magnet holder, thus making the
rear half weight as big as possible and this now weighed 8gr.

Again this did not provide good driveability or significantly better lap times (I didn’t even record them at this stage).

Now we really had a problem since there really isn’t anywhere in that car to put any more weight. I was already unhappy with the one underneath although I guessed you wouldn’t really ever see it with the car in motion.

Solution 4
Thinking out of the box about this specific car I had the thought that this was a car that existed in many versions. So I collected together about 10 photos that I have of this car in its different iterations and came to the conclusion that I could fabricate in lead a ‘wing’ standing tall above the car on stanchions (of soldered brass rod) and fix them to the car at the rear to make the Mexico 1968 version of the car.

(Now I know that this is officially the Lotus 49T (‘T’ for Tasman), not the European GP car but as I understand it apart from the fact that the engine had a capacity of 2.5l rather than 3l they were essentially the same car.)

That decided I cut a crude shape of wing and tapped it to the top of the gearbox to see how that would perform.

Extraordinarily it was a vast improvement. Still pretty slippery but absolutely what was needed.

The two weights brought the car up to 67gr some 18 above the original and 7gr above the prediction but this seemed to work well. With this set up I achieved a 4.4s lap pretty quickly and this was very ‘repeatable’ making for a good predictable ‘race able’ car. The quickest lap achieved was 4.3s.

Given the original lap time was 4.6s, plus the fact that (as we saw above) a probable lap difference from old to new track configurations represents about 0.3s this would equate to an old lap time of 4.0s, making this car at least comparable to the Group 1. cars and a total of 0.6s a lap quicker than ‘dry’.

The odd thing about this car is that unlike the Vanwall / Maserati the weighting made quite a small difference to the lap times despite the huge increase in driveability. This seems odd since one would think that driveability would quite quickly be translatable into control and therefore time saved. I suppose that given sufficient practice this might be the case, once one had adapted sufficiently one’s driving style but under my limited lap regime this didn’t occur.

My personal conclusion is that this car suffers from the repeated tyre compound problem. Once weighted the car was more driveable but still had far more power than traction making wheel spin inevitable under acceleration. Plus the motor sensitivity is just too high so that the slightest squeeze of the trigger creates too much power output (much like the real car at the beginning I believe). Again this must be tuneable with a better controller.

Solution 5
The thing that was not, in my opinion, adequate about Solution 4 was that the weight under the car was still necessary and that the high stanchions required would put the wing very high thus raising dramatically the centre of gravity. (The wing was also going to be hard to fix and easy to grab by my cat – which is not a small consideration in such matters!!).

So I looked again at various Lotus 49 solutions and happened upon a photo of Jochen Rindt at Monaco in 1970. In this form the rear spoiler was quite large, low and situated directly above the rear axle (as was logical in those early days of spoiler design).

So……. I soldered one up out of the lead sheet and with a couple of spacers to keep it level and off the gearbox and a couple of ‘prongs’ to locate it between the radius rods and suspension springs I had a weight of 15gr sitting exactly above the rear axle! (Plus its removable for adjustment / modification or showing the original car off.)

So now my Lotus 49 goes pretty well (despite the tyres) and weighs 64gr and I have to say it looks pretty good too (judge for yourselves) with the wing which obviously I need to paint and refinish to make it look better.

Of course one can easily criticise the crude soldering and the ‘attachment’ is not particularly robust but I’m going to rework the fixing when I have time in the future and try to further ‘finish’ it once I’ve got the undercoat on.


Obviously these cars are ‘perfect’ scale models as sold so my wing does tend to detract from this to some extent being far too ‘bulky’ as regards the section of the lead to be perfectly to scale. I’ve lightly rounded the edges, especially of the aerofoil sections to reduce the look of the bulk but obviously the more one files the lighter it gets and the subject of this study is performance not aesthetics as such so, so what.

Another option I looked at but didn’t execute would be the Monaco 1968 version which had a sort of flat inclined plate fixed over the engine. I don’t think, unless this was more than 1.5mm thick, this would alone provide all the weight necessary, meaning the under gearbox weight would also need to be employed. This would however be easier to model being essentially ‘flat’, if one felt the wing design was too complex and / or not sufficiently ‘beautiful’.

It also occurs to me that there is a business here for anyone who can fabricate a simple mould to cast these things in lead. Experiment might show that a few grams less would offer a more beautiful casting (especially if the side plates could be thinner), and this would be a great compromise.

Now, I understand that most English readers don’t have access (yet) to the Gold Leaf Lotus and obviously the earlier ‘BRG’ version would look unrealistic with wings but if I managed to buy a kit from Spain from Italy, you could have done too! Anyway, it looks like they’re coming eventually so you’ll just have to wait a little longer!

One final detail is that I now have to add the front side wings to ‘complete’ the car and I’m toying with the idea of doing this in lead rather than plastic just to add a few more grams of weight. I’ll do some tests first and let you know. The sad thing about this is that finally I’ll have to modify a car, since until now I’ve managed to do all of the above without once ‘damaging’ the original model.

Well, that’s all I have time for, I’ve got quite hot so I’m going to take my anorak off!

I hope someone out there enjoys what I’ve written and I’d be so happy to hear from anyone who’s done anything similar. If anyone’s got ideas how to further enhance performance on these cars I’d also be interested to hear and if anyone’s managed to chip the Maserati, Cooper T53 or Ferrari 156 I’d be REALLY interested to hear about it.


Keep motoring!
 

AR - November 2009

 

 

   Lo-Fi Version Time is now: 26th October 2014 - 04:20
© SlotForum Copyright Notice - Please Read / © Aviso de copyright SlotForum - Léanlo, por favor / © A proposito del Copyright del contenuto di Slotforum - Per favore leggere attentamente