Posted June 18, 201113 yr Its that time of year again, to make something big to crawl over stuff. This time I decided to make a massive truck with 8 PP wheels. After trying different designs in LDD I decided to use turntables in order to use planetary gear ratios inside each wheel like this: This way the end torque is high and the total half axle gear ratio is 1:5 allowing the truck to generate lots of torque with no problems of gear slippage or axle bending. To power the truck I used a combination of RC and PF's. The two independent RC motors use two indpendent gearboxes in order to power indpendent left/right side wheel drives. This way the trucks steers better. The PF M motors steer and switch gears, they are controlled by the RC unit. Suspension is a tatra styled design, which allows high ground clearance, robust design and is simple and reliable. The real life test came when it was time to shoot a video for the truck. I managed to find a nice muddy terrain with lots of bumps to try the suspension. Checking sideways stability. The truck never flipped: Going through sticky mud. The truck was ablt to go through mud with no issues. One of the toughest challenges is when going uphill. I managed to go up an uneven slope with no slippage. Another important test is the test of chassis. For best performance it should bend as little as possible. Notice the rear spoiler falled off, the ebnd is not as high as it looks: All in all I am very happy with this truck. Its one of my most capable and relaible big sized 8x8 so far. Specifications: Power: 2 RC motors Gearbox: dual synchronized gearbox Final gear rations: Low 1:50, high 1:16,67 Length: 60 cm Width 23 cm Height (-antenna) 22 cm Weight 3,2 kg Please check the video: Thanks!
June 18, 201113 yr It's unstoppable! The opening shot is great. Could you explain how the gearbox works, specifically how the two M motors are controlled from a single output?
June 18, 201113 yr Author The gearbox uses old ifferentials as 24 tooth gears and 16 tooth gears to get 1:1 and 1:3 gar ratio. Instad of using the usual gearbo handle, I used a 1x3 half beam, to move both gearboxes (left and right one) at once. In order to controll 2 M motors from RC motor i used the RC unit's steering ouput to steer the old 9V switch, which gets power from main motors and uses it to power the steering M motor. The secondary RC unit's output powers the egarbox M motor via PF convertible cable. Thanks for the praise"
June 18, 201113 yr Best Trial Truck ever? Congratulations, zblj! You're a genius All functions work very well, I especially like the suspension. It looks so real! Maybe you can take time to make a more detailed cab. I am sure that the chassis will handle the additional weight with ease And of course we need MANY pics of all the mechanisms of your truck
June 18, 201113 yr Nice work Zblj! I am glad you have returned to Tatra 8 x 8 (the first time I've met you in person you've been hiding behind one of those monsters). How are the technic turntable and planetary gears holding? I understand the in-wheel reduction, however you still have 8t gears. Well, I just made a TT once or twice before and they were quite sensitive. Whenever I see a new and improved model from you I do ask myself a question - can you do even better. And you keep surprising me Great job!
June 19, 201113 yr Author Nice work Zblj! I am glad you have returned to Tatra 8 x 8 (the first time I've met you in person you've been hiding behind one of those monsters). How are the technic turntable and planetary gears holding? I understand the in-wheel reduction, however you still have 8t gears. Well, I just made a TT once or twice before and they were quite sensitive. Whenever I see a new and improved model from you I do ask myself a question - can you do even better. And you keep surprising me Great job! Thanks! The 8 tooth gears are holding good, i checked them after shooting and there was no damage. The fact the load is evenly spread over 4 gears helps them to carry lots of power with no problems. Edited June 19, 201113 yr by Zblj
June 19, 201113 yr Same if i'm not a fan of 8*8 Trial Truck ( i think that 4*4 is much performant because they weight less and undergo under less stress), you did a good job ! I particulary like the planetary gear !
June 19, 201113 yr very good looking truck :) glad to see someone who uses the independent left an right drive like me :)
June 19, 201113 yr @ Zblj: Would you be willing to post the LDD .lxf file of your Planetary Gear assembly, like you did with your other excellent creations (like the Lynx)?
June 19, 201113 yr Yes, once I will be done with the whole truck in LDD Thanks, Jernej! You are by far the best LDD Technic modeler!
June 19, 201113 yr Surprisingly goes very well even with those massive wheels. If I were in your position, I would do the rear in red to go better with the stickers.
June 20, 201113 yr Wow! I really love this model, it will be very nice to see it loading another car when crawling in mud! I specially like the engineering resources to avoid the big PF-RC mocs problems in movility and steering. I just make an entry in my technic blog for this big model, I hope you like it, if not tell me... Tatra blog entry
June 21, 201113 yr Author Wow! I really love this model, it will be very nice to see it loading another car when crawling in mud! I specially like the engineering resources to avoid the big PF-RC mocs problems in movility and steering. I just make an entry in my technic blog for this big model, I hope you like it, if not tell me... Tatra blog entry Tank you very much, I like it!
June 21, 201113 yr Really nice. One day, when I've got plenty of bits, I'll try something like this myself. It's really inspiring to see your work. Keep it up!
August 5, 201113 yr Hello Zblj! I just got my hands on a full set of the Power Puller wheels, and I'm even MORE impressed with the truck you've build. Just now i'm starting to imagine how big it actually is. WOW! I would really appreciate it if you could share the construction of the planetary gear reductuon for the wheels, using a technic studless turntable. I have the feeling that this might be the best possible solution to make a sturdy and powerful mount for those huge wheels. Will be looking forward to your reply! Thanks!
August 7, 201113 yr Hello again! Today I put together the planetary hub. Amazing piece of engineering, very happy with how it works! Can't wait to build a wheel base and connect it to it! I did some modifications though, since i don't have one of the parts. All the parts i changed are in red. Take a look at it and tell me what you think. P.S. Oh, and thanks to Superkalle for the information on how to unloack LDD extended mode! Edited August 7, 201113 yr by le60head
August 7, 201113 yr @ le60head: When one clicks on the link you provided, we see a Bulgarian website asking for a login. The limit for attaching files to your post is 150k (not 3.61k, unless you already used 146k of your 150k allotment). We can't find the .lxf file link, and many people don't understand Bulgarian. Could you post the .lxf file here?
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