25th-Jan-21, 08:23 AM
DeSlots, DeSlots, DeSlots... 
When your car comes out of the slot , you lose time , risk damage to the car and (more often than not) lose the race.
In high level racing, a faultless set of laps without DeSlotting is the first minimum requirement to put yourself in a position of being able to win an event.
For me, its only a "good race night" if I have no unforced offs.
Just one "off" during the event can ruin your overall finishing position.
We can separate DeSlots into
A. Caused by Driver
B. Caused by Car
In this discussion, I'm going to focus primarily on B.
1. Start Line Power DeSlot.
The worst start to a race you can have.
Most common with angle winder motor configurations.
The car lifts the front clean out of the slot when you hit the power.
Added to the DeSlot is the location of the start line which is, more often than not, on a straight which is not covered by a marshal.
Even if the start line is covered by a marshal, they are often not paying attention to the start line as the rest of the field rushes away.
Contributory Causes:
High torque motor
Short Gear ratio
Suspension front/centre pivot(s) too tight and unable to absorb the initial power shock
One of the rear wheels is loose on the axle
Tyres moving on the rim
Too much rear end grip
Front of the car is too light
Braids too springy
High centre of gravity
Rear tyres not the same diameter because of tyre wear.
Fixes:
Change the gearing for more top end speed and less brutal start line acceleration.
Loosen your front suspension pivot so that it can absorb the shock as the motor climbs up the crown gear.
Add a small amount of silicone paste to the front motor mount spring simulate a damper.
Glue and true your tyres to the same diameter.
Crank back the attack curve on your electronic controller.
As a last resort you might want to add chassis weight close to the guide.
As a very last resort on the night, focus on not instantly snapping the throttle open at the start. Feed it in slowly.
2. Rollover on corner entry.
Causes:
Centre of Gravity is too high
Rear track too narrow
Too much Rear traction
Tyres too square edged
Fixes:
Lower your CofG :
- lightweight interiors,
- lightweight crystalwork.
- offset motor mount
- smaller rear wheels and tyres
Lower the rear wing height.
Round off the shoulders on both sides of the tyre
Increase your axial polar moment : Add chassis weight, (low and wide) as a last resort.
Loosen the front axle top set screws allowing the front axle some vertical movement.
Fit Zero-Grip front tyres or glaze your fronts with nail polish, superglue or epoxy resin.
3. Understeer on corner entry
The car goes straight on instead of traversing the corner.
Causes:
Front wheels anchored too low so the outer front wheel levers the guide blade out of the slot on corner entry.
Front tyres too grippy and too low.
Chassis twisted
Guide is not free to turn
Front body screw too tight
Guide is too loose a fit and is slopping about.
High speed Brake failure
Fixes:
Use the set screws to lift the front axle slightly or fit thinner tyres.
Flatten your chassis using a steel flat plate , magnets and hot water
If your guide is too shallow, slight variations on track surface combined with high cornering forces may trigger an understeer DeSlot.
You might want to experiment with Deeper blades.
Use softer braids. Lift and shape them slightly so that they can absorb the rail imperfections to mitigate the situation where contact might be lost leading to brake failure at high speeds.
Ensure your guide is free to move and self centres. Different manufacturers make differing guide shaft sizes so don't assume compatibility.
4. "Snap - roll" on corner exit .
This kind of DeSlot can be spectacular. The car pirhouetting vertically as the outside rear wheel induces lift and spin.
Causes:
Too much rear end grip
Loose suspension
Body attached too tight to the chassis
Rear tyres hit the wheel arch under extreme cornering
CofG too high
Guide is too loose a fit and is slopping about.
Motor torque too much for the car
Fixes:
Don't dope your tyres with oils and chemicals if it is not needed.
Harder rear tyres
Harder rear suspension springs
Allow the body shell to float on the chassis, longer body screws. Fettle the chassis to body contact surfaces.
Smaller rear wheels, skinnier tyres, fettle the wheel arches or narrow the rear track to bring the tyres inside the wheel arches (risks bringing on under steer de-slot behaviour)
Lower CofG (see above)
If your guide is very loose, the car may stutter mid corner because the inner braid loses contact.
As you open the throttle to compensate for the power loss , the guide sits flat again, contact is remade and the car is suddenly subjected to more voltage than it can handle.
5. Oversteer out of a corner?
The car slides the back end out wide until the blade has no more more movement remaining and twists the car out of the slot.
This is probably not a car problem.
Leave it later (out of the corner) before you open the throttle fully. As in Karting, Fast-Slotting is not achieved by "drifting"
Try to keep the back end grounded.
6. Straight line full speed "What the .... just happened?" de-slots
Heading down the straight and the car just jumps out? Ok some tracks are rough but:
- Is there anything trapped under your braids?
- Does an eyelet or soldered wire end protrude below the guide blade surface?
The braid's attack surface should be soft, not hard as an anvil.
- Does the blade and braid combination you are using just dig too deep into the track slot (and bottom out) ? Deep blades added to super skinny race braids can cause problems.
- does your front axle have enough free vertical movement ?
Fixes:
Fettle the the leading lower edge of the guide blade with a modelling knife, creating a wedge.
Use thicker braids or a shallower guide.
Shape the leading edge of the braid.
If the rail surface is genuinely very rough, maybe guide blade springs and/or rally blades are the way to go for your track.
Loosen off the top set screws (or otherwise adjust the axle) to allow front wheels a little more vertical movement so that a bump in the track does not transmit to the chassis.
Reslotting issues:
Remember also that after a DeSlot happens, the marshals have to get the car back in the slot ASAP.
Ensure your guide self centres to make it easier for the marshals to do this otherwise after 3 attempts, they will up-end your car, pull the guide straight and then reslot your car, wasting time !
Arrange your guide's power wires to centre the guide. Many chassis designs allow the wires to be held in place so that self centring can be easily done. Some wires are better at self centring than others. My preference is PSR silicone sheathed braided wires.
Impact DeSlot
A fun afterthought, (maybe not so much fun)
Despite your best car prep and conscious effort to improve driving techniques, other drivers can and will cause offs for you.
Deslotted cars in your lane are a hazard to be avoided if you can.
When racing, look ahead of your car. Digital racers learn this skill because a car-in-your-lane is the norm rather than the exception and planning ahead for overtaking manoevres is a key skill.
There are two schools of thought on stranded cars:
1. The NASCAR method.
Keep the peddle to the metal even if you can't see where the stranded car ended up (lost under a bridge maybe) and trust in dumb luck that you get through. The logic for this in 1:1 racing is that a spinning car ahead of you won't be there when you reach it.
If you're lucky, you are through and lose no time at all. (See " Days of Thunder" or Pixar's "Cars" for movies where this is shown)
If you are unlucky , high speed impact will deslot you and possibly cause a lot damage to both cars.
2. The F1 method.
Avoid contact with others at all costs.
Tip toe through blind sections and come to a complete halt if you can see a car is across your lane.
Your slot car is not as fragile as an f1 car but every contact risks damage.
As always, let us all know how YOU do things.
Discussion is always fruitful.
AlanW
When your car comes out of the slot , you lose time , risk damage to the car and (more often than not) lose the race.
In high level racing, a faultless set of laps without DeSlotting is the first minimum requirement to put yourself in a position of being able to win an event.
For me, its only a "good race night" if I have no unforced offs.
Just one "off" during the event can ruin your overall finishing position.
We can separate DeSlots into
A. Caused by Driver
B. Caused by Car
In this discussion, I'm going to focus primarily on B.
1. Start Line Power DeSlot.
The worst start to a race you can have.
Most common with angle winder motor configurations.
The car lifts the front clean out of the slot when you hit the power.
Added to the DeSlot is the location of the start line which is, more often than not, on a straight which is not covered by a marshal.
Even if the start line is covered by a marshal, they are often not paying attention to the start line as the rest of the field rushes away.
Contributory Causes:
High torque motor
Short Gear ratio
Suspension front/centre pivot(s) too tight and unable to absorb the initial power shock
One of the rear wheels is loose on the axle
Tyres moving on the rim
Too much rear end grip
Front of the car is too light
Braids too springy
High centre of gravity
Rear tyres not the same diameter because of tyre wear.
Fixes:
Change the gearing for more top end speed and less brutal start line acceleration.
Loosen your front suspension pivot so that it can absorb the shock as the motor climbs up the crown gear.
Add a small amount of silicone paste to the front motor mount spring simulate a damper.
Glue and true your tyres to the same diameter.
Crank back the attack curve on your electronic controller.
As a last resort you might want to add chassis weight close to the guide.
As a very last resort on the night, focus on not instantly snapping the throttle open at the start. Feed it in slowly.
2. Rollover on corner entry.
Causes:
Centre of Gravity is too high
Rear track too narrow
Too much Rear traction
Tyres too square edged
Fixes:
Lower your CofG :
- lightweight interiors,
- lightweight crystalwork.
- offset motor mount
- smaller rear wheels and tyres
Lower the rear wing height.
Round off the shoulders on both sides of the tyre
Increase your axial polar moment : Add chassis weight, (low and wide) as a last resort.
Loosen the front axle top set screws allowing the front axle some vertical movement.
Fit Zero-Grip front tyres or glaze your fronts with nail polish, superglue or epoxy resin.
3. Understeer on corner entry
The car goes straight on instead of traversing the corner.
Causes:
Front wheels anchored too low so the outer front wheel levers the guide blade out of the slot on corner entry.
Front tyres too grippy and too low.
Chassis twisted
Guide is not free to turn
Front body screw too tight
Guide is too loose a fit and is slopping about.
High speed Brake failure
Fixes:
Use the set screws to lift the front axle slightly or fit thinner tyres.
Flatten your chassis using a steel flat plate , magnets and hot water
If your guide is too shallow, slight variations on track surface combined with high cornering forces may trigger an understeer DeSlot.
You might want to experiment with Deeper blades.
Use softer braids. Lift and shape them slightly so that they can absorb the rail imperfections to mitigate the situation where contact might be lost leading to brake failure at high speeds.
Ensure your guide is free to move and self centres. Different manufacturers make differing guide shaft sizes so don't assume compatibility.
4. "Snap - roll" on corner exit .
This kind of DeSlot can be spectacular. The car pirhouetting vertically as the outside rear wheel induces lift and spin.
Causes:
Too much rear end grip
Loose suspension
Body attached too tight to the chassis
Rear tyres hit the wheel arch under extreme cornering
CofG too high
Guide is too loose a fit and is slopping about.
Motor torque too much for the car
Fixes:
Don't dope your tyres with oils and chemicals if it is not needed.
Harder rear tyres
Harder rear suspension springs
Allow the body shell to float on the chassis, longer body screws. Fettle the chassis to body contact surfaces.
Smaller rear wheels, skinnier tyres, fettle the wheel arches or narrow the rear track to bring the tyres inside the wheel arches (risks bringing on under steer de-slot behaviour)
Lower CofG (see above)
If your guide is very loose, the car may stutter mid corner because the inner braid loses contact.
As you open the throttle to compensate for the power loss , the guide sits flat again, contact is remade and the car is suddenly subjected to more voltage than it can handle.
5. Oversteer out of a corner?
The car slides the back end out wide until the blade has no more more movement remaining and twists the car out of the slot.
This is probably not a car problem.
Leave it later (out of the corner) before you open the throttle fully. As in Karting, Fast-Slotting is not achieved by "drifting"
Try to keep the back end grounded.
6. Straight line full speed "What the .... just happened?" de-slots
Heading down the straight and the car just jumps out? Ok some tracks are rough but:
- Is there anything trapped under your braids?
- Does an eyelet or soldered wire end protrude below the guide blade surface?
The braid's attack surface should be soft, not hard as an anvil.
- Does the blade and braid combination you are using just dig too deep into the track slot (and bottom out) ? Deep blades added to super skinny race braids can cause problems.
- does your front axle have enough free vertical movement ?
Fixes:
Fettle the the leading lower edge of the guide blade with a modelling knife, creating a wedge.
Use thicker braids or a shallower guide.
Shape the leading edge of the braid.
If the rail surface is genuinely very rough, maybe guide blade springs and/or rally blades are the way to go for your track.
Loosen off the top set screws (or otherwise adjust the axle) to allow front wheels a little more vertical movement so that a bump in the track does not transmit to the chassis.
Reslotting issues:
Remember also that after a DeSlot happens, the marshals have to get the car back in the slot ASAP.
Ensure your guide self centres to make it easier for the marshals to do this otherwise after 3 attempts, they will up-end your car, pull the guide straight and then reslot your car, wasting time !
Arrange your guide's power wires to centre the guide. Many chassis designs allow the wires to be held in place so that self centring can be easily done. Some wires are better at self centring than others. My preference is PSR silicone sheathed braided wires.
Impact DeSlot
A fun afterthought, (maybe not so much fun)
Despite your best car prep and conscious effort to improve driving techniques, other drivers can and will cause offs for you.
Deslotted cars in your lane are a hazard to be avoided if you can.
When racing, look ahead of your car. Digital racers learn this skill because a car-in-your-lane is the norm rather than the exception and planning ahead for overtaking manoevres is a key skill.
There are two schools of thought on stranded cars:
1. The NASCAR method.
Keep the peddle to the metal even if you can't see where the stranded car ended up (lost under a bridge maybe) and trust in dumb luck that you get through. The logic for this in 1:1 racing is that a spinning car ahead of you won't be there when you reach it.
If you're lucky, you are through and lose no time at all. (See " Days of Thunder" or Pixar's "Cars" for movies where this is shown)
If you are unlucky , high speed impact will deslot you and possibly cause a lot damage to both cars.
2. The F1 method.
Avoid contact with others at all costs.
Tip toe through blind sections and come to a complete halt if you can see a car is across your lane.
Your slot car is not as fragile as an f1 car but every contact risks damage.
As always, let us all know how YOU do things.
Discussion is always fruitful.
AlanW
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