Black Arrow - Black Bull - Printable Version

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Black Arrow - Black Bull - Nonfractal - 15th-Jan-21

Black Arrow - Black Bull

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Given that Black Arrow is not a homologated manufacturer at my home club, what possessed me to engage in this notoriously difficult kit build?

"What do you want for Christmas dad?"

Hmm....
Which kit is going to challenge me during CoViD lockdown-2?
Which kit would be a useful weapon at other clubs and venues? Maybe wood tracks?
Which kit has presented BIG problems for other builder/racers?

Black Arrow are not typically available from UK suppliers.
SlotCarUnion supplied the kit

The car is a 1/32 scale representation of a Laborghini Murcielago.

[attachment=11522]

The kit arrives in a cardboard box, no crystal display case or instructions included.
In the box are several zip lock bags containing all of the parts.
The component count is above 60 of which about 40 constitute the body components. A simple build this is not.
Very small parts are part of this build. There are even front and rear tow hoops which are indeed very small.

Job 1. Find the build instructions and lay the components out.
PDF available from black arrow's website for the build of the body only.
Split the components into "chassis" and "body" and began construction.

I immediately hit a known issue with the motor mount.
(Noted by an experienced builder, Alexis "in Greece" Gaitanis on another forum)
The sioux motor will not fit into the mount without bending the lower motor connector through 90 degrees.
I entertained the idea of drilling the motor mount but this is would have left its strength dangerously compromised.
A tip here is to use needle nose pliers to hold the connector in place while it is being bent. With pliers in place, no stress is put on the connector and a good 1mm radius can be achieved. The motor mount is chamfered at the point where the connector exists the motor end can so its not too hard to get this fitment right.

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The motor mount is untypical in that the motor can move and be locked into position to optimise the gear mesh.
It might even be possible to use slightly differently sized crowns and pinions in this mount.

Suspension on a factory fit kit!
The blackbull is supplied with a 4 point suspension and black arrow Red springs.
For all other manufacturers , suspension is a post factory upgrade option.
The motor mount 4-point is not rectangular (not like a slot.IT mount) but is arranged as a front centre pivot, a rear centre pivot and a pair of outer pivots, left and right.

[attachment=11525]

Apart from the motor issue, the chassis build was a pleasure.
Everything fitted. The guide is the best precision fit i have ever seen yet it swivels cleanly and self centres perfectly.
The factory fit braids look really good. No need to retrofit my usual NSR 0.2mm race braid

Building the body would only be a pleasure for a masochist.
I had made a decision to build the kit as per factory spec. No upgrades, no lightweight interior, no lexan crystalwork replacements etc so I diligently followed the PDF instructions.
Slavishly following the instructions left me with a roll cage in the (inevitable) small collection of small pieces left over.
The roll cage is not shown in the instructions. Pulling the interior out to to fit the roll cage invites refit problems.

[attachment=11526]

The most challenging part of the build came from the small parts, especially the small photo etched grille work.
None of the etchwork fitted properly. The rear centre grille is shown as a complex 3d shape (in the instructions) but the actual item is dead flat. The instructions state "use flat plate to adapt photo etched parts" but there is no way to achieve this so the grille was installed as a flat piece.

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The decalwork was somewhat problematic with some of the decals fracturing while being wetted for fitting.
The wind screen black surround decal fractured and had to be cut into a single sun strip.
The lightning strike decals are very skinny and required a lot of care to stop them breaking during fitment.
The "black arrow" decal for the rear wing is white which will not work on the white wing.
I painted the window wiper black because I found the white plastic didn't look right.
The car would look better if the white parts were all cast in black.

The wheel trims fitted without fettling.
The mirrors fitted easily.
The front winglets were difficult to fit (2 each side) because they are so small.

Crystalwork fitted well apart from the rear motor view triple hexagon window (supplied as 3 separate parts, not the single unit shown in the instructions) and required glue because the fitting pegs did not align to the windows.

[attachment=11528]

On the rolling Road, the black bull pulls 8.4 metres per second at 12v, higher than factory fitted kits from other manufacturers.
The gearing is quite long for a factory fitted car.
Crown 30 teeth, 16 mm diameter
Pinion 13 teeth, 7.5 mm diameter
Wheel diameter in factory fitted tyres. 20mm
Ratio 2.3
Rollout is 27mm per rev.

The completed model (in factory trim) weighs in at 79g.

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Was this car "Designed for a job" ?
This model is unique and contradictory in many respects.
The main contradiction is that this kit does not know whether it is a shelf queen display car or a "race it like you stole it" car.
There are sooooo many small and fragile components.
The rear wing supports will certainly not survive impact, making those on the Racer Sideways Huracan look very sturdy in comparison.

[attachment=11529]

The Sioux motor is listed as zero downforce leading to the conclusion that this car was designed for a series where flux leakage is forbidden.

So, my best guess is that this car was designed to race in a Spanish "no downforce" formula, possibly against sports cars like the NSR Mosler (fitted with Spanish King motors?)
On paper, the black arrow would be a match for a Mosler of this specification.

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Did I get this car for "a job" ? Yes.
LSC Wood Green club has separate classes for "Sports Car" and "GT".
Sportscar class is dominated by powerful "spec A" angle winder motors.
GT is dominated by powerful long can "spec A" inline motors because use of angle winders is restricted to "spec B" motors of 23k rpm and 280 gcm.
By fluke maybe, the Sioux motor (22krpm 280gcm) comes closer to the max spec-B permitted than any other motor I've found.

The GT lap record at LSC ( London Wood Green ) is held by the late John Secchi with an anglewinder black arrow ferrari GT italia so that is a formula I feel that I have to pursue.

I will write more on this model once we are all back up and racing.

Tool Tips
Tweezers are very useful for the small parts in this build.
1.5mm Allen Key (hex driver) is required.

In summary
As a racer, the car is yet to be tested but shows lots of promise.
For the home toy market, this car should be avoided because the build is too complex.
For shelf queen builders, a nice addition to your collection (if you have the time and patience to build the car to a high standard).

The build did take a lot of time but I enjoyed the challenge.
I'm hopeful that this car will be able to hold its own against other GT class cars at LSC but if it doesn't, upgrades will be coming to move it from GT class to SportsCar class. Lightweight interior, NSR King30 motor probably.
I can see the black bull needing new wing supports after its first impact so rubberised wing and supports will also be on the shopping list or fabrication list depending on availability.

Comments welcome :)
Alan

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RE: Black Arrow - Black Bull - JasonB - 15th-Jan-21

Blimey.

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RE: Black Arrow - Black Bull - BAracer - 15th-Jan-21

Less than a month since Christmas Day, so not too long a build! 

Just a few queries...

I looked at the Black Arrow website and see they offer body kits and lexan interiors, so how about building a new lightweight, robust, race ready body, rather than spoil your efforts on the 'show' body...how hard do you think you would be able to race that 'show' body?!

The diamond pod layout seems simple but inspired, is it unique to BA? 

How does the adjustable motor positioning work? How rigid is the motor held once you get your optimum set up?

Does suspension 'harm' a car raced on wood?

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RE: Black Arrow - Black Bull - KensRedZed - 15th-Jan-21

Very cool looking car, and suspension detail.

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RE: Black Arrow - Black Bull - Nonfractal - 16th-Jan-21

(15th-Jan-21, 07:44 PM)BourneAgainRacer Wrote:  I looked at the Black Arrow website and see they offer body kits and lexan interiors, so how about building a new lightweight, robust, race ready body, rather than spoil your efforts on the 'show' body...how hard do you think you would be able to race that 'show' body?!

The diamond pod layout seems simple but inspired, is it unique to BA? 

How does the adjustable motor positioning work? How rigid is the motor held once you get your optimum set up?
Does suspension 'harm' a car raced on wood?

Racing limited edition coollector versions and show bodies is how I roll 
I don't have shelf queens. Maybe just some "ladies in waiting" ( waiting to see the track during lockdown )  

Lightweight interior and crystalwork will probably be fitted at the time that the body is repainted after some hard racing.

The sliding motor is enabled by elongated motor screw slots. Low tech but effective.

Having a single front pivot is common (NSR, Thunderslot, Avant, scaleauto and others) but a single centre rear pivot I've not seen before. 
Having body mount points along the centre line (with set screw body balancers) is increasing in popularity. 
Even NSR is starting to design cars this way. Maybe centre line motor mount points will also grow in popularity. 
Many believe that suspension is only good for soaking up bumps on bad plastic tracks but for me that is not the whole story. 
Suspension enables and controls weight transfer during cornering and has an impact on handling irrespective of the smoothness (or not) of the track.

Alan

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RE: Black Arrow - Black Bull - chrisguyw - 16th-Jan-21

(16th-Jan-21, 07:17 AM)Nonfractal Wrote:  Having a single front pivot is common (NSR, Thunderslot, Avant, scaleauto and others) but a single centre rear pivot I've not seen before. 

Even NSR is starting to design cars this way. Maybe centre line motor mount points will also grow in popularity. 


Alan

FYI, All of the MRSlotcar motor pods have been designed with  single, centrally located  pod lugs (front and rear)  since the brands inception 10 years ago..........roll stiffness is controlled by the lugs on either side of the pod.



A central pivot method like this allows the pod to "rotate" torsionally along the central axis of the chassis which from a chassis dynamics perspective, is preferable to the "tilting" movement that is the result of pods with more than one front/rear pod lug, and , lugs that are not located on the chassis centerline.

The central pivot point on the MRSlotcar pod/chassis, mimics the similarly designed "flexi-board"/ center hinge chassis designs that have been the favoured chassis design in high end slot car racing for over 40years.

Will we see more manufacturers adopting this design ??.......from a pure performance perspective we should, however, considering this would create added cost, and also would render some of the existing products as less attractive to the consumer, I suspect it will take some time.......... remember that several elements of the current "plastic" cars (Gear design, Motor pods, etc.) were designed from an manufacturing, and, ease of use from the consumer perspective,...not,....from a pure performance perspective.

Cheers
Chris Walker

While some may well have seen the MRSlotcar chassis, some obviously have not.
(There are different pods to accept, FK180/FC130/FF050 motors, in inline,side, and anglewinder configurations.)

This one has a "Neo" magnet FF050 installed.

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RE: Black Arrow - Black Bull - BAracer - 16th-Jan-21

Hidden in plain sight! 

I have seen that photo before but never noticed the single fixing at the rear...

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RE: Black Arrow - Black Bull - Savage GT - 20th-Jan-21

Thanks for the review nonfractual 
I hate dealing with etched parts, they often seem to be problematic little beggars on plastic kits
Could I ask what are the dimensions to the outside tyre widths, and guide pivot centre to rear axle ?
Is the Sioux motor a more linear and drivable motor than the Apache ?

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RE: Black Arrow - Black Bull - Nonfractal - 20th-Jan-21

Can't get to my tools right now but I can give you some comparisons.

The guide pivot to rear axle measurement is approximately 5mm  longer than the mosler.
The body is approximately 65mm at the rear but the wheels could be drawn in significantly if needed to meet classification rules.

The car cannot be raced until uk lockdown is eased.

I have never seen an apache motor. 
Alan W

[attachment=11643]

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RE: Black Arrow - Black Bull - Nonfractal - 19th-Jun-21

First test 
LSC London 
Tuesday 15th June 2021

GT class at LSC
Type "b" motors as described above.

Scalextric sport track, urethane tyres 

This class of racing is packed full of long can inline cars from NSR and Slot.it

Testing of the black bull went very well. 
The car was smooth and stable.
I'd go as far as to say that this ie the best "first test" of a car I've ever done.

Did I choose to race the black bull in the night? 
In short, no
My car for the night was an NSR ASV , lightweight components, nsr king 30 motor inline.

The sheer power of the king motor completely outperformed  the black arrow sioux.
Not surprising that this class is dominated by powerful inline motors.

So, what next for the black bull? 
Can't use it at nascot wood. Black arrow is not an endorsed manufacturer


Time to get the thinking cap on.
Do I dare try this fragile beast as a proxy car? 
Would this work as an oxigen digital car ?
Should I optimise this car for wood racing? 

Next test, wood track. Milton Keynes Racewars venue on Monday...
I'll post the testing feedback early next week.

Alan

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