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crazy_1993 posted a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThe Enforcer is back and better than ever before! Support on CUUSOO! Introduction The Enforcer is a fully motorised remote control Technic off road vehicle. The vehicle has a police theme and is loosely based on the Hummer H2 but many subtle changes have been made to obey copyright restrictions. Here are some examples of the inspiration for my design: The Enforcer was originally an entry for the ‘You Design It, We Make It’ competition but ended up coming in second place to rm88’s ‘Boss’ crawler. However I do not think that it is the end of the road for the Enforcer. The Enforcer Recharged is a massive overhaul of the original Enforcer. Firstly, as this is CUUSOO, the original 9398 chassis could not be used anymore, so the chassis has undergone a massive redesign to adapt it specially to the Enforcer’s needs. The winch has now been motorised and all lights are now power functions. The battery box has now been changed to a 8878 rechargeable battery box which reduces weight massively (by about 160g) and is more convenient. There is now no need to remove the battery box so this allowed major part optimisations to be made. The result is this, The Enforcer Recharged: Note: LDD does not contain certain power functions elements so in some images the following elements will be represented as shown: Chassis The Enforcer now uses a redesigned chassis and not the 9398 chassis.: The new chassis does not have 4 wheel steering like the 9398 as I did not think that it was needed on a model of this theme. The 88004 servo motor for steering is now located in the front suspension module. The chassis is powered by one central 8882 extra large motor transmitting power to all wheels through the power joint system, unlike the 9398 which had one 88003 large motor for drive above each axle. Below is a diagram of the drive-train and gearing: I have now changed the design of the drivetrain to prevent breakages of the gears in and driving the centre differential. The older style non-bevelled differential is now used and the gearing converts the torque from the XL motor to RPM before reaching the centre differential. Further gear reduction has been added after the two axle differentials to maintain an overall gear ratio of 1 : 6.72. The gearing results in 0.44 times the original torque on the centre differential. That's 40.2 mNm with an RPM of 495. I am just finishing the casing for the new rear axle module. I am also thinking of working on an alternate setup which is the 9398 chassis with the battery box changed for the rechargeable version so that the bodywork can still be directly attached. Here are some comparisons between the 9398 crawler chassis and the Enforcer chassis to show how the gear ratios were decided. These stats have yet to be updated for the new drivetrain: Because the extra large motor does not deliver quite as much total power as the two large motors, two gear configurations are available for speed focused or torque focused performance. This is shown in the drivetrain diagram above the table. Although the 8878 rechargeable battery box only outputs 7.2V which is less than the 9V from the 8881 AA battery box, this voltage is more consistent because the voltage from a Lithium polymer battery remains constant until the charge is depleted, whereas the voltage from AA batteries drops significantly throughout use. Note that unlike the 9398 chassis, the front and rear differentials need to be facing in opposite directions as shown, otherwise the wheels will not rotate in the same direction: On the Enforcer chassis, the space above the rear axle in the rear suspension module is occupied by an 8878 rechargeable battery box which is much lighter and more convenient than the regular 8881 battery box. More importantly, this means that the battery box does not need to be removed to change the batteries, it can just be plugged into the charger without being removed. This allowed the bodywork to be built directly on to the chassis, saving parts. Another main feature of the chassis is the dual shock absorbers above each wheel. This is to help prevent the easy rolling behaviour which is common in Technic off-road vehicles with a heavier bodywork and to scale the suspension stiffness more appropriately to the weight of the model. Softer suspension such as using only one shock absorber per wheel results in the bodywork leaning away from the chassis on lateral inclines, causing premature tipping so the new design helps prevent this: Care had to be taken to allow each shock absorber joint to rotate on two axes to allow the front and rear axles to move freely with the suspension. The main image shows the shock absorbers functioning. Different Forms The model with the most features has a very high part count so I have decided to make multiple versions of the model simplified to various degrees for different and slightly more practical part counts. The features of each version are shown below: Features on all models All models feature 4 opening doors, an opening tailgate and an opening bonnet. The doors feature compound hinges to allow the doors to fit into their frames properly. Each door also has a rotary handle to secure the door shut with: The tailgate has a sliding handle which locks it in place when closed: All models also feature power functions headlights and taillights which can be switched on or off while driving: All models except the Enforcer Rapid Response have a rear roof section which can be removed for an alternate form. Charging can be done easily by opening the rear door: The Enforcer Elite The Enforcer Elite features power functions flashing police lights. The flashing is performed by a mechanism containing a medium motor and 2 control switches: The same motor is also linked to a piston engine in the bonnet: The gear ratios mean that the piston engine will run at 127rpm and the light flashing system will be driven at 26.4rpm which will result in the police lights performing one on/off cycle every 1.14 seconds. The Enforcer Elite contains a front mounted winch powered by a medium motor which is shown on the left in the above diagram. The gear ratio for this winch is the same as the gear ratio for the winch on the Unimog U400 (1 : 24 gear ratio, 15.8rpm winch speed, 40mNm torque). The winch would also contains a clutch gear to avoid damage in the event of a string jam or when the winch is fully reeled in. This is replaced by one of the white 24 teeth gears in the render as LDD does not contain the clutch gear. The Enforcer Elite will be controlled with 2 8885 IR controllers. The power functions wiring layout needed to make the functions run correctly is shown below along with the physical locations of the PF elements: The Enforcer Standard Issue The Enforcer Standard Issue shares largely the same bodywork as the Elite version but does not contain the winch, flashing police lights or piston engine to reduce the part count and number of power functions elements required. The bonnet has been modified to accommodate the removal of the piston engine. The power functions lights are now turned on and off by a control switch in the boot which can be accessed by removing the rear roof section. The switch can be secured on with the red push bolt. The power functions wiring and layout for this model are shown below: The Enforcer Rapid Response The Enforcer Rapid Response shares the same functions as the Enforcer Standard Issue but has the entire roof removed for a whole new look and a lighter and faster feel along with a further reduced part count. Possible Stickers The Enforcer has potential for a great sticker set to emphasize the police theme. Below is an example of a possible sticker set: SUPPORT NOW ON CUUSOO!!! Thank you for taking your time to read this, all support is greatly appreciated!