doug72 Posted September 2, 2017 Posted September 2, 2017 (edited) The “Boydell Stomper” My “Wacky Wheels” vehicle is based on old technology that used a type of wheel invented by Boydell in 1846 which preceded caterpillar tracks in an attempt to allow heavy traction engines and artillery guns to cross soft ground and by the weirdest tank ever built, the experimental Russian Tsar Tank built in 1914 which was a complete failure !! Wheels now built:- Each wheel has a series of “feet” that spread the load. Each “foot” has a degree of movement allowing two feet to be in contact with the ground at at any one time, providing an endless track for the wheel to roll along. Can also climb shallow steps. My MOC will use a tricycle arrangement with two large diameter using “Boydell” wheels at the front with a smaller 3rd. wheel at the rear for steering. The two Boydell wheels will be chain driven by an XL motor via a differential. Steering will by servo motor moving the rear castor wheel as per the Tsar tank. Tried a subtractor unit for drive & steering but it was too weak and slow. The 3rd function will probably be a powered winch to help pull vehicle up steep slopes if required or by using shear legs be able to lift objects such as other “Wacky Wheels”. Next step is to build the frame to house motors etc. plus a drivers control cabin. Edited October 8, 2017 by Doug72 added content / removed image file info. Quote
MangaNOID Posted September 2, 2017 Posted September 2, 2017 That's not just wacky but also dam interesting! Quote
BrickbyBrickTechnic Posted September 2, 2017 Posted September 2, 2017 Interesting concept! Could you make the pictures bigger? They are tiny right now. Quote
doug72 Posted September 2, 2017 Author Posted September 2, 2017 (edited) 2 hours ago, BrickbyBrickTechnic said: Interesting concept! Could you make the pictures bigger? They are tiny right now. Here are bigger images: Edited September 2, 2017 by Doug72 Quote
Leonardo da Bricki Posted September 2, 2017 Posted September 2, 2017 Cool concept, I like the direction this is going! Quote
mocbuild101 Posted September 3, 2017 Posted September 3, 2017 Cool! But something I find funny is: Wheel in 1846 = ingenious solution Wheel in 2017 = crazy and wacky Lego wheel I bet Boydell never thought his idea would be used 171(!) years later! Quote
doug72 Posted September 3, 2017 Author Posted September 3, 2017 (edited) 11 hours ago, mocbuild101 said: Cool! But something I find funny is: Wheel in 1846 = ingenious solution Wheel in 2017 = crazy and wacky Lego wheel I bet Boydell never thought his idea would be used 171(!) years later! There were several other types of “walking wheels” developed in the late 19th and early 20th centuries. The pedrail wheel is a type of wheel developed in the early 20th century for all-terrain locomotion. They consist of a series of "feet" (pedes in Latin) connected to pivots on a wheel. As the wheel turns, the feet come into contact with the ground, and rotate so they remain flat to the ground as the wheel moves over them. Pedrail wheels may be simple systems with the feet connected to a rigid wheel, but more complex systems including various built-in suspension systems were designed to improve performance on uneven ground. L Difficult but not impossible to build using Lego. I chose the Boydell wheel as had enough parts to build it plus it used up un-used parts I obtained for my Bucket Chain Excavator, i.e chains & old style sprocket wheels. Currently developing a heavy duty differential as the standard Lego diffs are not strong enough and prone to the 12T single bevel gears failing under heavy load. Edited September 3, 2017 by Doug72 Quote
LEGO Train 12 Volts Posted September 3, 2017 Posted September 3, 2017 Very original idea ...I like this project! Quote
doug72 Posted September 4, 2017 Author Posted September 4, 2017 (edited) Progress : Heavy Duty Differential Ver. 1 Built using knob gears within a 5 x 7 frame and driven by a 60Z turntable. The other end of 5 x 7 frame supported by a 56Z turntable. The axle outputs have can have either 15T (blue) or 9T (Red) sprocket wheels to drive via chains the 21T (yellow) sprockets on the Boydell Wheels. Differential is driven by an M motor via double bevel gears to give 5:1 reduction. To prevent M motor fouling the Z60 turntable a 20T double bevel gear is used as an idler gear. i.e. 12 - 20 - 60 Result: too much friction in diff. and knob gears flexing occasionally causing one wheel to stall. Poor axle support causing Boydell wheels to bow outwards. Heavy Duty Differential Ver. 2 56Z turntable eliminated, support for knob gears improved along with improved axle support for drive outputs. Axle support for Boydell Wheels improved. L motor used for higher speed output with same 5:1 reduction and same chain drive to both wheels. Result : Improved and steadier rotation with much less friction and less bowing of wheels. I hope to keep the chain drive but will test wheel rotation without it. 21T yellow sprocket gears are used as they have a good arrangment of pin holes to allow wheel spokes to be at 90. degs. Edited September 5, 2017 by Doug72 Quote
schraubedrin Posted September 4, 2017 Posted September 4, 2017 11 minutes ago, Doug72 said: How did you fix those Axle and Pin Connector Angled #2 ? Are they still removable from the frame? Quote
Boulderer Posted September 4, 2017 Posted September 4, 2017 Just now, schraubedrin said: How did you fix those Axle and Pin Connector Angled #2 ? Are they still removable from the frame? I was just about to ask the same question. Quote
doug72 Posted September 4, 2017 Author Posted September 4, 2017 Just now, schraubedrin said: How did you fix those Axle and Pin Connector Angled #2 ? Are they still removable from the frame? Wondered who would be the first to spot that. They are fixed using 2L red axles and yes they can be removed quite easilly. 3L axles could be used if they don't foul other parts. Quote
Boulderer Posted September 4, 2017 Posted September 4, 2017 6 minutes ago, Doug72 said: They are fixed using 2L red axles and yes they can be removed quite easilly. How do you remove them? Quote
doug72 Posted September 4, 2017 Author Posted September 4, 2017 (edited) 3 minutes ago, Boulderer said: How do you remove them? By using a sharp needle point you can prise them out far enough to grip with needle nose pliers. Edited September 4, 2017 by Doug72 Quote
Boulderer Posted September 4, 2017 Posted September 4, 2017 (edited) Metal on plastic ... ouch!! I know we have illegal building techniques but, do we have any illegal disassembly techniques? Edited September 4, 2017 by Boulderer typo corrected Quote
doug72 Posted September 4, 2017 Author Posted September 4, 2017 (edited) No 2L axles were harmed during removal. A 2L axle with stop would be useful. Edited September 4, 2017 by Doug72 Quote
Davidz90 Posted September 4, 2017 Posted September 4, 2017 Great idea! Choosing the right size for third wheel is interesting problem - as far as I remember, excessive ground pressure on it was one of the major problems of this "tank". Quote
doug72 Posted September 4, 2017 Author Posted September 4, 2017 1 hour ago, Davidz90 said: Great idea! Choosing the right size for third wheel is interesting problem - as far as I remember, excessive ground pressure on it was one of the major problems of this "tank". The huge wheels were intended to cross significant obstacles. However, due to miscalculations of the weight, the rear wheel was prone to getting stuck in soft ground and ditches, and the front wheels were sometimes insufficient to pull it out. This led to a fiasco of tests before the high commission in August 1915. The tank remained in the location where it was tested, some 60 kilometres from Moscow until 1923 when it was finally taken apart for scrap. Quote
doug72 Posted September 5, 2017 Author Posted September 5, 2017 (edited) 22 hours ago, Davidz90 said: Great idea! Choosing the right size for third wheel is interesting problem - as far as I remember, excessive ground pressure on it was one of the major problems of this "tank". Should be no problem as don't intend to use it over a swamp or soft ground as the Tsar Tank did. Progress : I have decided to dispense with the chain drive & sprockets as they were causing too much friction making wheel rotation jerky. The support for the wheel axles was also causing them to lean outwards. Wheels are now directly driven by the differential unit. Wheels centres now re-built using a 3739 wheel hub which allows for six spokes to be attached. The wheel hub also has much less friction where it contacts the side frames and at the same time stops wheels leaning outwards. Wheel rotation now much improved and tire destructor devices added to wheel centres to combat other vehicles !! Next step is to build the steering unit using 1 of 2 possible solutions. 1/. Servo motor driving a gear or crank arm or 2/. Linear actuator moving a tiller arm. The rear steering unit probably use either a single wheel or 2 wheels close together. A dummy Vee 8 engine will be used driven somehow from drive uint. Edited September 5, 2017 by Doug72 Quote
Seasider Posted September 5, 2017 Posted September 5, 2017 I'm starting to think mine is going to be too tame when I see things like this. But then I'm determined to get mine built now I have the idea in my head! Quote
Kelkschiz Posted September 5, 2017 Posted September 5, 2017 I think you are not the only one building this. Saw some very similar images on Sariel's facebook. I am pretty amazed. Never knew about this experimental tank before. Great idea for a MOC! Quote
doug72 Posted September 5, 2017 Author Posted September 5, 2017 9 minutes ago, Jim said: This is exactly what we are looking for! Thanks Jim, makes a welcome change from four wheel super cars ! Quote
Jim Posted September 5, 2017 Posted September 5, 2017 Just now, Doug72 said: Thanks Jim, makes a welcome change from four wheel super cars ! Exactly! Quote
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